51
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Zhang X, Sun X, Jiang R, Zeng EY, Sunderland EM, Muir DCG. Response to Comment on "Screening New Persistent and Bioaccumulative Organics in China's Inventory of Industrial Chemicals": A Call for Further Environmental Research on Organosilicons Produced in China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:693-696. [PMID: 34694120 DOI: 10.1021/acs.est.1c05528] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- Xianming Zhang
- Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Xiangfei Sun
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Ruifen Jiang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Eddy Y Zeng
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Elsie M Sunderland
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge Massachusetts 02138, United States
| | - Derek C G Muir
- Environment and Climate Change Canada, Aquatic Contaminants Research Division, 867 Lakeshore Road, Burlington, Ontario Canada L7S 1A1
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52
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Ding Y, Lu H, Mou Q, Peng D, Yu M, Wu Y. A DFT study on the cyclization-degradation mechanism for phenylmethylsiloxanes in thermal vacuum. Polym Degrad Stab 2022. [DOI: 10.1016/j.polymdegradstab.2021.109802] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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53
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Su Y, Hu X, Tang H, Lu K, Li H, Liu S, Xing B, Ji R. Steam disinfection releases micro(nano)plastics from silicone-rubber baby teats as examined by optical photothermal infrared microspectroscopy. NATURE NANOTECHNOLOGY 2022; 17:76-85. [PMID: 34764453 DOI: 10.1038/s41565-021-00998-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 09/06/2021] [Indexed: 05/06/2023]
Abstract
Silicone-rubber baby teats used to bottle-feed infants are frequently disinfected by moist heating. However, infant exposure to small microplastics (<10 μm) potentially released from the heated teats by hydrothermal decomposition has not been studied, owing to the limitations of conventional spectroscopy in visualizing microplastic formation and in characterizing the particles at the submicrometre scale. Here both the surfaces of silicone teats subjected to steam disinfection and the wash waters of the steamed teats were analysed using optical-photothermal infrared microspectroscopy. This new technique revealed submicrometre-resolved steam etching on and chemical modification of the teat surface. Numerous flake- or oil-film-shaped micro(nano)plastics (MNPs) (in the size range of 0.6-332 μm) presented in the wash waters, including cyclic and branched polysiloxanes or polyimides, which were generated by the steam-induced degradation of the base polydimethylsiloxane elastomer and the polyamide resin additive. The results indicated that by the age of one year, a baby could ingest >0.66 million elastomer-derived micro-sized plastics (MPs) (roughly 81% in 1.5-10 μm). Global MP emission from teat disinfection may be as high as 5.2 × 1013 particles per year. Our findings highlight an entry route for surface-active silicone-rubber-derived MNPs into both the human body and the environment. The health and environmental risks of the particles are as yet unknown.
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Affiliation(s)
- Yu Su
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China
| | - Xi Hu
- Quantum Design (Beijing) Co., Ltd, Beijing, China
| | - Hongjie Tang
- Quantum Design (Beijing) Co., Ltd, Beijing, China
| | - Kun Lu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China
| | - Huimin Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China
| | - Sijin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, USA.
| | - Rong Ji
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China.
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54
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Amemori S, Hamamoto R, Mizuno M. Enhancement of association constants of various charge-transfer complexes in siloxane solvents. NEW J CHEM 2022. [DOI: 10.1039/d2nj00214k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The association constants of various charge-transfer complexes were evaluated in n-hexane, octamethyltrisiloxane and PDMS to investigate the solvent effect.
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Affiliation(s)
- Shogo Amemori
- NanoMaterials Research Institute, Kanazawa University, Kanazawa 920-1192, Japan
- Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan
| | - Ryosuke Hamamoto
- School of Chemistry, College of Science and Engineering, Kanazawa University, Kanazawa 920-1192, Japan
| | - Motohiro Mizuno
- NanoMaterials Research Institute, Kanazawa University, Kanazawa 920-1192, Japan
- Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan
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55
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Fouilloux H, Rager MN, Ríos P, Conejero S, Thomas CM. Highly Efficient Synthesis of Poly(silylether)s: Access to Degradable Polymers from Renewable Resources. Angew Chem Int Ed Engl 2021; 61:e202113443. [PMID: 34902211 DOI: 10.1002/anie.202113443] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Indexed: 12/14/2022]
Abstract
The design of new materials with tunable properties and intrinsic recyclability, derived from biomass under mild conditions, stands as a gold standard in polymer chemistry. Reported herein are platinum complexes which catalyze the formation of poly(silylether)s (PSEs) at low catalyst loadings. These polymers are directly obtained from dual-functional biobased building blocks such as 5-hydroxymethylfurfural (HMF) or vanillin, coupled with various dihydrosilanes. Access to different types of copolymer architectures (statistical or alternating) is highlighted by several synthetic strategies. The materials obtained were then characterized as low Tg materials (ranging from -60 to 29 °C), stable upon heating (T-5% up to 301 °C) and resistant towards uncatalyzed methanolysis. Additionally, quantitative chemical recycling of several PSEs could be triggered by acid-catalyzed hydrolysis or methanolysis. These results emphasize the interest of biobased poly(silylether)s as sustainable materials with high recycling potential.
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Affiliation(s)
- Hugo Fouilloux
- PSL University, Chimie ParisTech, CNRS, Institut de Recherche de Chimie Paris, Paris, 75005, France
| | - Marie-Noelle Rager
- PSL University, Chimie ParisTech, CNRS, Institut de Recherche de Chimie Paris, Paris, 75005, France
| | - Pablo Ríos
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica, Centro de Innovación en Química Avanzada (ORFEO-CINCA), CSIC and Universidad de Sevilla, Avda. Américo Vespucio 49, 41092, Sevilla, Spain
| | - Salvador Conejero
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica, Centro de Innovación en Química Avanzada (ORFEO-CINCA), CSIC and Universidad de Sevilla, Avda. Américo Vespucio 49, 41092, Sevilla, Spain
| | - Christophe M Thomas
- PSL University, Chimie ParisTech, CNRS, Institut de Recherche de Chimie Paris, Paris, 75005, France
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56
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Krüger O, Ebner I, Kappenstein O, Roloff A, Luch A, Bruhn T. Towards a better comparability during GMP assessment – Identifying the main parameters that influence the loss of volatile organic compounds from silicone elastomers. Food Packag Shelf Life 2021. [DOI: 10.1016/j.fpsl.2021.100758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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57
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Kong S, Wang R, Feng S, Wang D. Tannic Acid as a Natural Crosslinker for Catalyst-Free Silicone Elastomers From Hydrogen Bonding to Covalent Bonding. Front Chem 2021; 9:778896. [PMID: 34733824 PMCID: PMC8558560 DOI: 10.3389/fchem.2021.778896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 10/04/2021] [Indexed: 11/13/2022] Open
Abstract
The construction of silicone elastomers crosslinked by a natural crosslinker under a catalyst-free method is highly desirable. Herein we present catalyst-free silicone elastomers (SEs) by simply introducing tannic acid (TA) as a natural crosslinker when using poly (aminopropylmethylsiloxane-co-dimethylsiloxane) (PAPMS) as the base polymer. The crosslinked bonding of these SEs can be easily changed from hydrogen bonding to covalent bonding by altering the curing reaction from room temperature to heating condition. The formability and mechanical properties of the SEs can be tuned by altering various factors, including processing technique, the amount of TA and aminopropyl-terminated polydimethylsiloxane, the molecular weight and -NH2 content of PAPMS, and the amount of reinforcing filler. The hydrogen bonding was proved by the reversible crosslinking of the elastomers, which can be gradually dissolved in tetrahydrofuran and re-formed after removing the solvent. The covalent bonding was proved by a model reaction of catechol and n-decylamine and occurred through a combination of hydroxylamine reaction and Michael addition reaction. These elastomers exhibit good thermal stability and excellent hydrophobic property and can bond iron sheets to hold the weight of 500 g, indicating their promising as adhesives. These results reveal that TA as a natural product is a suitable “green” crosslinker for the construction of catalyst-free silicone elastomers by a simple crosslinking strategy. Under this strategy, TA and more natural polyphenols could be certainly utilized as crosslinkers to fabricate more organic elastomers by selecting amine-containing polymers and further explore their extensive applications in adhesives, sealants, insulators, sensors, and so forth.
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Affiliation(s)
- Sen Kong
- National Engineering Research Center for Colloidal Materials and Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, China
| | - Rui Wang
- National Engineering Research Center for Colloidal Materials and Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, China
| | - Shengyu Feng
- National Engineering Research Center for Colloidal Materials and Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, China.,Shandong Key Laboratory of Advanced Organosilicon Materials and Technologies and State Key Laboratory of Fluorinated Functional Membrane Materials, Zibo, China
| | - Dengxu Wang
- National Engineering Research Center for Colloidal Materials and Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, China.,Shandong Key Laboratory of Advanced Organosilicon Materials and Technologies and State Key Laboratory of Fluorinated Functional Membrane Materials, Zibo, China
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58
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Zheng L, Nie X, Wu Y, Wang P. Construction of Si‐Stereogenic Silanes through C−H Activation Approach. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101084] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Long Zheng
- School of Chemistry and Material Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou 310024 China
- State key laboratory of organometallic chemistry Center for excellence in molecular synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences CAS 345 Lingling Road Shanghai 200032 P. R. China
| | - Xiao‐Xue Nie
- State key laboratory of organometallic chemistry Center for excellence in molecular synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences CAS 345 Lingling Road Shanghai 200032 P. R. China
| | - Yichen Wu
- State key laboratory of organometallic chemistry Center for excellence in molecular synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences CAS 345 Lingling Road Shanghai 200032 P. R. China
| | - Peng Wang
- School of Chemistry and Material Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou 310024 China
- State key laboratory of organometallic chemistry Center for excellence in molecular synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences CAS 345 Lingling Road Shanghai 200032 P. R. China
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59
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Brounstein Z, Zhao J, Geller D, Gupta N, Labouriau A. Long-Term Thermal Aging of Modified Sylgard 184 Formulations. Polymers (Basel) 2021; 13:polym13183125. [PMID: 34578026 PMCID: PMC8466950 DOI: 10.3390/polym13183125] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 11/28/2022] Open
Abstract
Primarily used as an encapsulant and soft adhesive, Sylgard 184 is an engineered, high-performance silicone polymer that has applications spanning microfluidics, microelectromechanical systems, mechanobiology, and protecting electronic and non-electronic devices and equipment. Despite its ubiquity, there are improvements to be considered, namely, decreasing its gel point at room temperature, understanding volatile gas products upon aging, and determining how material properties change over its lifespan. In this work, these aspects were investigated by incorporating well-defined compounds (the Ashby–Karstedt catalyst and tetrakis (dimethylsiloxy) silane) into Sylgard 184 to make modified formulations. As a result of these additions, the curing time at room temperature was accelerated, which allowed for Sylgard 184 to be useful within a much shorter time frame. Additionally, long-term thermal accelerated aging was performed on Sylgard 184 and its modifications in order to create predictive lifetime models for its volatile gas generation and material properties.
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Affiliation(s)
- Zachary Brounstein
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA; (Z.B.); (D.G.); (N.G.)
- Department of Nanoscience and Microsystems Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Jianchao Zhao
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Drew Geller
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA; (Z.B.); (D.G.); (N.G.)
| | - Nevin Gupta
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA; (Z.B.); (D.G.); (N.G.)
| | - Andrea Labouriau
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA; (Z.B.); (D.G.); (N.G.)
- Correspondence:
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60
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Wang F, Qiu L, Tian Y. Super Anti-Wetting Colorimetric Starch-Based Film Modified with Poly(dimethylsiloxane) and Micro-/Nano-Starch for Aquatic-Product Freshness Monitoring. Biomacromolecules 2021; 22:3769-3779. [PMID: 34432419 DOI: 10.1021/acs.biomac.1c00588] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Colorimetric starch film containing anthocyanins is extensively used in eco-friendly intelligent food packaging, but its high water wettability limits its practical application in the food industry. Herein, a super anti-wetting colorimetric starch film was prepared by surface modification with a nano-starch/poly(dimethylsiloxane) (PDMS) composite coating. The water sensitivity, optical properties, mechanical properties, surface morphology, and surface chemical composition of this film were systemically investigated by multiple methods. The obtained film exhibited an extremely high water contact angle (152.46°) and low sliding angle (8.15°) owing to the hierarchical micro-/nanostructure formed by nano-starch aggregates combined with the low-surface-energy PDMS covering. The anti-wettability, optical barrier, and mechanical properties of this film were also significantly improved. The self-cleaning and liquid-food-repelling abilities of this film were comprehensively confirmed. Moreover, this super anti-wetting colorimetric starch film can be applied to monitor the freshness of aquatic products without being disabled by water.
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Affiliation(s)
- Fan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China.,School of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China
| | - Lizhong Qiu
- Zhucheng Xingmao Corn Developing Co., Ltd., Weifang 262200, P. R. China
| | - Yaoqi Tian
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China.,School of Food Science and Technology, Jiangnan University, Wuxi 214122, P. R. China.,Zhucheng Xingmao Corn Developing Co., Ltd., Weifang 262200, P. R. China
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61
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González-Hernández P, Pacheco-Fernández I, Bernardo F, Homem V, Pasán J, Ayala JH, Ratola N, Pino V. Headspace solid-phase microextraction based on the metal-organic framework CIM-80(Al) coating to determine volatile methylsiloxanes and musk fragrances in water samples using gas chromatography and mass spectrometry. Talanta 2021; 232:122440. [PMID: 34074425 DOI: 10.1016/j.talanta.2021.122440] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/31/2022]
Abstract
A headspace solid-phase microextraction (HS-SPME) method was developed using the metal-organic framework (MOF) CIM-80(Al) as extraction phase and in combination with gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 6 methylsiloxanes and 7 musk fragrances in different environmental waters. The chromatographic separation was optimized in different GC instruments equipped with different detectors, allowing the correct separation and identification of the compounds. The HS-SPME method was optimized using a Box-Behnken experimental design, while the validation was carried out together with the most suitable commercial fiber (divinylbenzene/polydimethylsiloxane) for comparison purposes. The MOF-based coating was particularly efficient for the determination of volatile methylsiloxanes, showing moderately lower limits of detection (of 0.2 and 0.5 μg L-1versus 0.6 μg L-1 for cyclic methylsiloxanes) and slightly better precision (relative standard deviation values lower than 17% versus 22%) than the commercial coating, while avoiding the cross-contamination issues associated to the polymeric composition of commercial fibers. The method was applied for the analysis of seawater and wastewater samples, allowing the quantification of several analytes and the assessment of matrix effects. The proposed HS-SPME method using the CIM-80(Al) fiber constitutes a more environmentally friendly, simpler, and efficient strategy in comparison with other sample preparation methods using different extraction techniques, while the use of a MOF as fiber sorbent constitutes a potential alternative to exploit the features of SPME for the challenging environmental monitoring of these compounds.
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Affiliation(s)
- Providencia González-Hernández
- Laboratorio de Materiales para Análisis Químico (MAT4LL), Departamento de Química, Unidad Departamental de Química Analítica, Universidad de La Laguna (ULL), Tenerife, 38206, Spain; Laboratory for Process Engineering, Environment, Biotechnology and Energy (LEPABE), Department of Chemical Engineering, University of Porto, Porto, 4200-465, Portugal.
| | - Idaira Pacheco-Fernández
- Laboratorio de Materiales para Análisis Químico (MAT4LL), Departamento de Química, Unidad Departamental de Química Analítica, Universidad de La Laguna (ULL), Tenerife, 38206, Spain.
| | - Fábio Bernardo
- Laboratory for Process Engineering, Environment, Biotechnology and Energy (LEPABE), Department of Chemical Engineering, University of Porto, Porto, 4200-465, Portugal.
| | - Vera Homem
- Laboratory for Process Engineering, Environment, Biotechnology and Energy (LEPABE), Department of Chemical Engineering, University of Porto, Porto, 4200-465, Portugal.
| | - Jorge Pasán
- Laboratorio de Materiales para Análisis Químico (MAT4LL), Departamento de Física, Universidad de La Laguna (ULL), La Laguna, Tenerife, 38206, Spain.
| | - Juan H Ayala
- Laboratorio de Materiales para Análisis Químico (MAT4LL), Departamento de Química, Unidad Departamental de Química Analítica, Universidad de La Laguna (ULL), Tenerife, 38206, Spain.
| | - Nuno Ratola
- Laboratory for Process Engineering, Environment, Biotechnology and Energy (LEPABE), Department of Chemical Engineering, University of Porto, Porto, 4200-465, Portugal.
| | - Verónica Pino
- Laboratorio de Materiales para Análisis Químico (MAT4LL), Departamento de Química, Unidad Departamental de Química Analítica, Universidad de La Laguna (ULL), Tenerife, 38206, Spain; Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias, Universidad de La Laguna (ULL), Tenerife, 38206, Spain.
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62
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Liu Q, Huang W, Liu B, Wang PC, Chen HB. Gamma Radiation Chemistry of Polydimethylsiloxane Foam in Radiation-Thermal Environments: Experiments and Simulations. ACS APPLIED MATERIALS & INTERFACES 2021; 13:41287-41302. [PMID: 34410100 DOI: 10.1021/acsami.1c10765] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The γ radiolysis behavior of polydimethylsiloxane (PDMS) in the radiation-thermal environments (dose rate, 0.2 Gy/s) is studied to pinpoint the basic knowledge of the temperature (20-70 °C) effects. The non-monotonous temperature effects on the formation of gas products, paramagnetic species in silica, and cross-linking density are proposed to correlate with the complex chemical reaction mechanisms. Besides, molecular dynamics simulation and theoretical calculation are first performed simultaneously based on the radical chemistry and intricate material composition, making it easier to comprehend and further harness the radiolysis mechanisms and structure deterioration of PDMS. The γ radiation-induced primary gas products and dominant cross-linking phenomena are reproduced by the molecular dynamics simulations with a reactive force field, and the reaction mechanisms and physicochemical interactions among PDMS chains, gas products, reactive radicals, and silica fillers are thoroughly studied at the atomic scale. The thermochemistry of the barrierless radical coupling reactions and reactions with explicit high-barrier transition states is calculated at the M06-2X theoretical level with the 6-311g(d, p) basis set. The barrierless reactions are all exothermal with the heat release of 321-618 kJ/mol, while the potential barriers for reactions with explicit transition states vary between 37 and 229 kJ/mol. The results show that γ radiation-induced radicals are crucial for the ensuing gas formation and cross-linking reactions, especially for the radical coupling reactions. The radical chemistry involved in the radiolytic PDMS is the key to understand and simulate its radiolysis behavior, according to the experimental and simulated results.
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Affiliation(s)
- Qiang Liu
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621000, China
| | - Wei Huang
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621000, China
| | - Bo Liu
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621000, China
| | - Pu-Cheng Wang
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621000, China
| | - Hong-Bing Chen
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621000, China
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63
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Xiang X, Liu N, Xu L, Cai Y. Review of recent findings on occurrence and fates of siloxanes in environmental compartments. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 224:112631. [PMID: 34416634 DOI: 10.1016/j.ecoenv.2021.112631] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/08/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
In view of their vast global usage in both consumer products and industrial processes, environmental emission and fates of siloxanes have become concerned issue. This review summarized the research progress, especially in the last decade, on production/consumption data, toxicities, analysis methods, environmental distribution, migration and degradation/transformation of both dimethylsiloxanes and modified siloxanes in atmospheric, aquatic and terrestrial compartments from various areas (especially in China). In spite of their fast degradation (hydrolysis and hydroxylation, etc) in various matrices (except sediment), dimethylsiloxane oligomers have been found in various environmental matrices from many countries due to their constant usage and emission. Moreover, recent literatures have paid attention to behaviors of dimethylsiloxanes in industrial areas, e.g., their higher residual levels compared with residential areas and unique transformed products (such as halogenated products) arose from special industrial production scenarios. Meanwhile, although most prior studies focused on dimethylsiloxanes, identification of modified-siloxanes with other functional groups in environment have been beginning to attract the attention of scientists. Furthermore, related literatures indicated that compared with dimethylsiloxanes, both halogenated-dimethylsiloxanes and modified methylsiloxanes (phenylsiloxanes and trifluoropropylsiloxanes) could have stronger persistence due to their weaker volatilization and degradation, especially in terrestrial matrices.
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Affiliation(s)
- Xiaoling Xiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Nannan Liu
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China
| | - Lin Xu
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China.
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China
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64
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Naturally Derived Silicone Surfactants Based on Saccharides and Cysteamine. Molecules 2021; 26:molecules26164802. [PMID: 34443391 PMCID: PMC8399498 DOI: 10.3390/molecules26164802] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/03/2021] [Accepted: 08/05/2021] [Indexed: 11/17/2022] Open
Abstract
Silicone surfactants are widely used in many industries and mostly rely on poly(ethylene glycol) (PEG) as the hydrophile. This can be disadvantageous because commercial PEG examples vary significantly in polydispersity—constraining control over surface activity of the surfactant—and there are environmental concerns associated with PEG. Herein, we report a three-step synthetic method for the preparation of saccharide-silicone surfactants using the natural linker, cysteamine, and saccharide lactones. The Piers–Rubinsztajn plus thiol-ene plus amidation process is attractive for several reasons: if employed in the correct synthetic order, it allows for precise tailoring of both hydrophobe and hydrophile; it permits the ready utilization of natural hydrophiles cysteamine and saccharides in combination with silicones, which have significantly better environmental profiles than PEG; and the products exhibit interesting surface activities.
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Ortiz-Ardila AE, Díez B, Celis C, Jenicek P, Labatut R. Microaerobic conditions in anaerobic sludge promote changes in bacterial composition favouring biodegradation of polymeric siloxanes. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1182-1197. [PMID: 34302159 DOI: 10.1039/d1em00143d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Volatile organic silicon compounds (VOSiC) are harmful pollutants to the biota and ecological dynamics as well as biogas-based energy conversion systems. However, there is a lack of understanding regarding the source of VOSiCs in biogas, especially arising from the biochemical conversion of siloxane polymers such as polydimethylsiloxanes (PDMS). The biodegradation of PDMS was evaluated under anaerobic/microaerobic conditions (PO2 = 0, 1, 3, 5%), using wastewater treatment plant (WWTP) sludge as an inoculum and PDMS as a co-substrate (0, 50, 100, 500 ppm). On average, strictly anaerobic treatments produced significantly less methane than the 3 and 5% microaerated ones, which show the highest PMDS biodegradation at 50 ppm. Thauera sp. and Rhodococcus sp. related phylotypes were identified as the most abundant bacterial groups in microaerated treatments, and siloxane-related molecules were identified as remnants of PDMS catabolism. Our study demonstrates that microaeration promotes changes to the native bacterial community which favour the biological degradation of PDMS. This confirms that the presence of VOSiC (e.g., D4-D6) in biogas is not only due to its direct input in wastewaters, but also to the PDMS microbial catabolism. Microaerobic conditions enhance both PDMS and (subsequent) VOSiC degradation in the liquid phase, increasing the concentrations of D4 and D5 in biogas, and the production of less toxic siloxane-based derivatives in the liquid phase. This study suggests that microaeration of the anaerobic sludge can significantly decrease the concentration of PDMSs in the WWTP effluent. However, for WWTPs to become effective barriers for the emission of these ecotoxic contaminants to the environment, such a strategy needs to be coupled with an efficient biodegradation of VOSiCs from the biogas.
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Affiliation(s)
- A E Ortiz-Ardila
- Department of Hydraulic and Environmental Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.
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66
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Liu N, Sun H, Xu L, Cai Y. Methylsiloxanes in petroleum refinery facility: Their sources, emissions, environmental distributions and occupational exposure. ENVIRONMENT INTERNATIONAL 2021; 152:106471. [PMID: 33676090 DOI: 10.1016/j.envint.2021.106471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 06/12/2023]
Abstract
High concentrations (1.08 ng/g-3.61 mg/g) of methylsiloxanes, including cyclic analogs [octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6)], and linear analogs with 3-14 silicon atoms (L3-L14), have been detected in crude oil, additives and petroleum products from one petroleum refinery facility in China. Overall, the total mass load of Σmethylsiloxanes (1320 kg/day) in crude oil and additives was 1.5 times higher than that in petroleum products (857 kg/day), indicating their potential emissions in this facility, which were further confirmed by the find of their obvious emission through exhaust-gas (89.4 kg/day) and wastewater (4.70 kg/day). Σmethylsiloxanes emission from exhaust-gas discharge outlets of deep catalytic cracking units (60.6 kg/day) took up 68% of their total emission from all gas outlets. Overall, Σmethylsiloxanes in air (17.1-743 μg/m3) and soil samples [311 ng/g dw (dry weight) - 34.2 μg/g dw] from this facility were up to four orders of magnitude greater than those from surrounding areas, and plasma concentrations of Σmethylsiloxanes in current workers from this facility (7.4-609 ng/mL) were up to two orders of magnitude larger than those from reference group (<LOQ-21.2 ng/mL). Furthermore, concentration ratios (0.09-0.58) of total cyclic methylsiloxanes to their hepatic metabolites for workers were 2.3-17 times lower than those (1.32-1.56) for reference group, indicating that refinery workers may be exposed to more unknown methylsiloxane analogs than general population.
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Affiliation(s)
- Nannan Liu
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China
| | - Hongyu Sun
- School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300350, China; Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, Tianjin 300384, China
| | - Lin Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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67
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Dankert F, Hänisch C. Siloxane Coordination Revisited: Si−O Bond Character, Reactivity and Magnificent Molecular Shapes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100275] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Fabian Dankert
- Leibniz-Institut für Katalyse e. V. (LIKAT Rostock) Albert-Einstein-Str. 29a 18059 Rostock Germany
| | - Carsten Hänisch
- Fachbereich Chemie und Wissenschaftliches Zentrum für Materialwissenschaften (WZMW) Philipps-Universität Marburg Hans-Meerwein-Straße 4 35032 Marburg Germany
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68
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Sarai N, Levin BJ, Roberts JM, Katsoulis DE, Arnold FH. Biocatalytic Transformations of Silicon-the Other Group 14 Element. ACS CENTRAL SCIENCE 2021; 7:944-953. [PMID: 34235255 PMCID: PMC8227617 DOI: 10.1021/acscentsci.1c00182] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Indexed: 05/30/2023]
Abstract
Significant inroads have been made using biocatalysts to perform new-to-nature reactions with high selectivity and efficiency. Meanwhile, advances in organosilicon chemistry have led to rich sets of reactions holding great synthetic value. Merging biocatalysis and silicon chemistry could yield new methods for the preparation of valuable organosilicon molecules as well as the degradation and valorization of undesired ones. Despite silicon's importance in the biosphere for its role in plant and diatom construction, it is not known to be incorporated into any primary or secondary metabolites. Enzymes have been found that act on silicon-containing molecules, but only a few are known to act directly on silicon centers. Protein engineering and evolution has and could continue to enable enzymes to catalyze useful organosilicon transformations, complementing and expanding upon current synthetic methods. The role of silicon in biology and the enzymes that act on silicon-containing molecules are reviewed to set the stage for a discussion of where biocatalysis and organosilicon chemistry may intersect.
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Affiliation(s)
- Nicholas
S. Sarai
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Benjamin J. Levin
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - John M. Roberts
- Dow
Inc., Core R&D, 633 Washington Street, Midland, Michigan 48667, United
States
| | - Dimitris E. Katsoulis
- Dow
Silicones Corporation, 2200 West Salzburg Road, Auburn, Michigan 48611, United
States
| | - Frances H. Arnold
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
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69
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Pascual C, Cantera S, Lebrero R. Volatile Siloxanes Emissions: Impact and Sustainable Abatement Perspectives. Trends Biotechnol 2021; 39:1245-1248. [PMID: 34167844 DOI: 10.1016/j.tibtech.2021.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 11/30/2022]
Abstract
Eliminating volatile siloxanes from gas emissions is increasingly important due to their persistent detrimental economic, societal, and environmental impacts. Although physicochemical technologies are currently the only commercially available abatement methods, recently developed biobased technologies are emerging as a more cost-effective and sustainable alternative to promote the removal of volatile siloxanes.
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Affiliation(s)
- Celia Pascual
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain
| | - Sara Cantera
- Laboratory of Microbiology, Wageningen University and Research Center, Campus Helix building 124 (Office 4030) Stippeneng 4, Wageningen 6708, WE, The Netherlands.
| | - Raquel Lebrero
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain; Institute of Sustainable Processes, University of Valladolid, Dr. Mergelina s/n., Valladolid 47011, Spain.
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70
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Bernardo F, González-Hernández P, Ratola N, Pino V, Alves A, Homem V. Using Design of Experiments to Optimize a Screening Analytical Methodology Based on Solid-Phase Microextraction/Gas Chromatography for the Determination of Volatile Methylsiloxanes in Water. Molecules 2021; 26:molecules26113429. [PMID: 34198808 PMCID: PMC8201336 DOI: 10.3390/molecules26113429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/28/2021] [Accepted: 05/31/2021] [Indexed: 11/16/2022] Open
Abstract
Volatile methylsiloxanes (VMSs) constitute a group of compounds used in a great variety of products, particularly personal care products. Due to their massive use, they are continually discharged into wastewater treatment plants and are increasingly being detected in wastewater and in the environment at low concentrations. The aim of this work was to develop and validate a fast and reliable methodology to screen seven VMSs in water samples, by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography with flame ionization detection (GC-FID). The influence of several factors affecting the extraction efficiency was investigated using a design of experiments approach. The main factors were selected (fiber type, sample volume, ionic strength, extraction and desorption time, extraction and desorption temperature) and optimized, employing a central composite design. The optimal conditions were: 65 µm PDMS/Divinylbenzene fiber, 10 mL sample, 19.5% NaCl, 39 min extraction time, 10 min desorption time, and 33 °C and 240 °C as extraction and desorption temperature, respectively. The methodology was successfully validated, showing low detection limits (up to 24 ng/L), good precision (relative standard deviations below 15%), and accuracy ranging from 62% to 104% in wastewater, tap, and river water samples.
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Affiliation(s)
- Fábio Bernardo
- LEPABE—Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (F.B.); (N.R.); (A.A.)
| | - Providencia González-Hernández
- Unidad Departamental de Química Analítica, Universidad de La Laguna (ULL), La Laguna, 38206 Tenerife, Spain; (P.G.-H.); (V.P.)
| | - Nuno Ratola
- LEPABE—Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (F.B.); (N.R.); (A.A.)
| | - Verónica Pino
- Unidad Departamental de Química Analítica, Universidad de La Laguna (ULL), La Laguna, 38206 Tenerife, Spain; (P.G.-H.); (V.P.)
- Institute of Tropical Diseases and Public Health, Universidad de La Laguna (ULL), La Laguna, 38206 Tenerife, Spain
| | - Arminda Alves
- LEPABE—Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (F.B.); (N.R.); (A.A.)
| | - Vera Homem
- LEPABE—Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; (F.B.); (N.R.); (A.A.)
- Correspondence:
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71
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Guo M, Huang Y, Chen Z, Zhang Y, Zhang Y, Zhu M, Zhang J, Feng S. Preparation and Properties of Benzylsulfonyl-Containing Silicone Copolymers via Ring-opening Copolymerization of Macroheterocyclosiloxane and Cyclosiloxane. Chemistry 2021; 27:7897-7907. [PMID: 33783909 DOI: 10.1002/chem.202100309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Indexed: 11/07/2022]
Abstract
Ring-opening copolymerization (ROCP) of benzylsulfonyl macroheterocyclosiloxane (BSM) and five different cyclosiloxanes was systematically investigated. A general approach for the synthesis of benzylsulfonyl-containing silicone copolymers with various substituents, including methyl, vinyl, ethyl, and phenyl, was developed herein. A series of copolymers with variable incorporation (from 6 % to 82 %) of BSM were obtained by modifying the comonomer feed ratio and using KOH as the catalyst in a mixed solvent of dimethylformamide and toluene. The obtained copolymers exhibited various composition-dependent properties and unique viscoelasticity. Notably, the surface and fluorescent characteristics as well as the glass transition temperatures of the copolymers could be tailored by varying the amount of BSM. Unlike typical sulfone-containing polymers, such as poly(olefin sulfone)s, the prepared copolymers displayed excellent thermal and hydrolytic stability. The universal strategy developed in the present study provides a platform for the design of innovative silicone copolymers with adjustable structures and performance.
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Affiliation(s)
- Mengdong Guo
- Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education Department, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250199, P. R. China
| | - Yue Huang
- Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education Department, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250199, P. R. China
| | - Zhongkai Chen
- Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education Department, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250199, P. R. China
| | - Yangping Zhang
- Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education Department, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250199, P. R. China
| | - Ya Zhang
- Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education Department, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250199, P. R. China
| | - Mingquan Zhu
- Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education Department, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250199, P. R. China
| | - Jie Zhang
- Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education Department, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250199, P. R. China
| | - Shengyu Feng
- Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education Department, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250199, P. R. China
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72
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Exposure to Dodecamethylcyclohexasiloxane (D6) Affects the Antioxidant Response and Gene Expression of Procambarus clarkii. SUSTAINABILITY 2021. [DOI: 10.3390/su13063495] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Dodecamethylcyclohexasiloxane (D6) is widely used daily in the chemical industry and exists in the environment; however, its eco-toxicity is not well documented. A hydroponic experiment was performed to investigate the effects of D6 exposure (10–1000 mg L−1) on oxidative stress induction and gene expression changes in crayfish (Procambarus clarkii). The results showed that superoxide dismutase (SOD) activity was enhanced by 20–32% at low D6 exposure (10 mg L−1) in muscle but reduced in gill tissue at high D6 exposure (1000 mg L−1). High D6 (1000 mg L−1) also increased catalase (CAT) and peroxidase (POD) activities in muscle tissue by 14–37% and 14–45%, respectively, and the same trend was observed in the carapace and gill tissue of crayfish. The Malondialdehyde (MDA), ascorbate (AsA), and glutathione (GSH) contents were increased by 16–31%, 19–31%, and 21–28% in the muscle of crayfish under D6 exposure. Additionally, silicon (Si) content increased in three organs (gill, carapace, and muscle) of crayfish. Related genes involved in enzyme and nonenzyme activities were detected, and when crayfish was exposed to D6, genes such as Sod3, Cat3, Pod3, and Gsh3 were up-regulated, while Asa3 and Oxido3 were significantly down-regulated in the muscle. The research results help us to understand the toxicity of D6 in crayfish and provide a basis for further research on the mechanism of D6-induced stress in crayfish and other aquatic organisms.
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73
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Hou X, Zheng Y, Ma X, Liu Y, Ma Z. The Effects of Hydrophobicity and Textural Properties on Hexamethyldisiloxane Adsorption in Reduced Graphene Oxide Aerogels. Molecules 2021; 26:1130. [PMID: 33672689 PMCID: PMC7924388 DOI: 10.3390/molecules26041130] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 02/07/2023] Open
Abstract
To expand the applications of graphene-based materials to biogas purification, a series of reduced graphene oxide aerogels (rGOAs) were prepared from industrial grade graphene oxide using a simple hydrothermal method. The influences of the hydrothermal preparation temperature on the textural properties, hydrophobicity and physisorption behavior of the rGOAs were investigated using a range of physical and spectroscopic techniques. The results showed that the rGOAs had a macro-porous three-dimensional network structure. Raising the hydrothermal treatment temperature reduced the number of oxygen-containing groups, whereas the specific surface area (SBET), micropore volume (Vmicro) and water contact angle values of the rGOAs all increased. The dynamic adsorption properties of the rGOAs towards hexamethyldisiloxane (L2) increased with increasing hydrothermal treatment temperature and the breakthrough adsorption capacity showed a significant linear association with SBET, Vmicro and contact angle. There was a significant negative association between the breakthrough time and inlet concentration of L2, and the relationship could be reliably predicted with a simple empirical formula. L2 adsorption also increased with decreasing bed temperature. Saturated rGOAs were readily regenerated by a brief heat-treatment at 100 °C. This study has demonstrated the potential of novel rGOA for applications using adsorbents to remove siloxanes from biogas.
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Affiliation(s)
- Xifeng Hou
- Hebei Key Laboratory of Inorganic Nano-Materilas, College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, Hebei, China; (X.H.); (Y.Z.)
| | - Yanhui Zheng
- Hebei Key Laboratory of Inorganic Nano-Materilas, College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, Hebei, China; (X.H.); (Y.Z.)
- Shijiazhuang Vocational College of Finance & Economics, Shijiazhuang 050061, Hebei, China
| | - Xiaolong Ma
- School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, Hebei, China;
| | - Yuheng Liu
- College of Pharmaceutical Sciences, Hebei Medical University, Shijiazhuang 050017, Hebei, China;
| | - Zichuan Ma
- Hebei Key Laboratory of Inorganic Nano-Materilas, College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, Hebei, China; (X.H.); (Y.Z.)
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74
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Cheng Z, Qiu X, Shi X, Zhu T. Identification of organosiloxanes in ambient fine particulate matters using an untargeted strategy via gas chromatography and time-of-flight mass spectrometry. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 271:116128. [PMID: 33421844 DOI: 10.1016/j.envpol.2020.116128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
Organosilicons are widely used in consumer products and are ubiquitous in living environments. However, there is little systemic information on this group of pollutants in ambient particles. This study proposes a novel untargeted strategy based mainly on the mass difference of three silicon isotopes to screen organosilicon compounds from 2-year PM2.5 samples of Beijing using gas chromatography and high-resolution time-of-flight mass spectrometry. 61 organosilicons were filtered from 1019 peaks, and 35 ones were identified as organosiloxanes including 17 methylsiloxanes and 18 phenylmethylsiloxanes, of which 6 and 3 species were confirmed using reference standards, respectively. These organosiloxanes could be clustered into three groups: low-silicon-number methylsiloxanes, high-silicon-number methylsiloxanes, and phenylmethylsiloxanes. Low-silicon-number methylsiloxanes showed high abundance in the heating season but low abundance in the non-heating season, whereas high-silicon-number methylsiloxanes showed the opposite seasonal variation. This study provides a promising strategy for screening organosilicon compounds through an untargeted approach and gives insights for further investigation of the sources and health risks of organosiloxanes.
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Affiliation(s)
- Zhen Cheng
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
| | - Xinghua Qiu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China.
| | - Xiaodi Shi
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
| | - Tong Zhu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
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75
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Amemori S, Kikuchi K, Mizuno M. Poly(dimethylsiloxane) and oligo(dimethylsiloxane) solvent effects on aromatic donor-acceptor interactions. Chem Commun (Camb) 2021; 57:1141-1144. [PMID: 33410835 DOI: 10.1039/d0cc06638a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Solvents with a wide range of polarities, including poly(dimethylsiloxane) and oligo(dimethylsiloxane), were used to evaluate aromatic donor-acceptor interactions between pyrene and pyromellitic diimide derivatives. The donor-acceptor interactions were stronger in siloxane solvents than in aliphatic solvents, possibly because of the poor solubility of the aromatics in siloxanes.
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Affiliation(s)
- Shogo Amemori
- NanoMaterials Research Institute, Kanazawa University, Kanazawa 920-1192, Japan.
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76
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Liu YQ, Wrona M, Su QZ, Vera P, Nerín C, Hu CY. Influence of cooking conditions on the migration of silicone oligomers from silicone rubber baking molds to food simulants. Food Chem 2021; 347:128964. [PMID: 33453582 DOI: 10.1016/j.foodchem.2020.128964] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/17/2020] [Accepted: 12/23/2020] [Indexed: 11/30/2022]
Abstract
The stability, surface micromorphology, and volatile organic compounds (VOCs) of silicone rubber baking molds (SRBMs) were tested while using the molds under severe conditions: baking at 175 °C, microwaving at 800 W, and freezing at -18 °C. Moreover, migration tests of SRBMs to food simulants (isooctane, 95% ethanol, and Tenax®) at 70 °C for 2 h (accelerated conditions) were performed. The initial total VOCs concentration was 2.53% higher than that recommended by BfR Recommendations on Food Contact Materials. Therefore, the SRBM samples were considered as badly tempered materials, and 18 different types of silicone oligomers were identified during the migration tests. The following percentage of silicone oligomers with a molecular weight lower than 1000 Da in isooctane, 95% ethanol, and Tenax® were detected: 70.7%, 91.8%, and 97.2%, respectively. It has been proven that previous baking treatments effectively reduced the content of silicone oligomers migrating from SRBMs.
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Affiliation(s)
- Yi-Qi Liu
- Department of Food Science & Engineering, Jinan University, Huangpu West Avenue 601, Guangzhou City 510632, Guangdong, China
| | - Magdalena Wrona
- Department of Analytical Chemistry, Aragon Institute of Engineering Research I3A, CPS-University of Zaragoza, Torres Quevedo Building, María de Luna 3, 50018 Zaragoza, Spain
| | - Qi-Zhi Su
- Department of Analytical Chemistry, Aragon Institute of Engineering Research I3A, CPS-University of Zaragoza, Torres Quevedo Building, María de Luna 3, 50018 Zaragoza, Spain
| | - Paula Vera
- Department of Analytical Chemistry, Aragon Institute of Engineering Research I3A, CPS-University of Zaragoza, Torres Quevedo Building, María de Luna 3, 50018 Zaragoza, Spain
| | - Cristina Nerín
- Department of Analytical Chemistry, Aragon Institute of Engineering Research I3A, CPS-University of Zaragoza, Torres Quevedo Building, María de Luna 3, 50018 Zaragoza, Spain.
| | - Chang-Ying Hu
- Department of Food Science & Engineering, Jinan University, Huangpu West Avenue 601, Guangzhou City 510632, Guangdong, China.
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77
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Brown WL, Day DA, Stark H, Pagonis D, Krechmer JE, Liu X, Price DJ, Katz EF, DeCarlo PF, Masoud CG, Wang DS, Hildebrandt Ruiz L, Arata C, Lunderberg DM, Goldstein AH, Farmer DK, Vance ME, Jimenez JL. Real-time organic aerosol chemical speciation in the indoor environment using extractive electrospray ionization mass spectrometry. INDOOR AIR 2021; 31:141-155. [PMID: 32696534 DOI: 10.1111/ina.12721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/06/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
Understanding the sources and composition of organic aerosol (OA) in indoor environments requires rapid measurements, since many emissions and processes have short timescales. However, real-time molecular-level OA measurements have not been reported indoors. Here, we present quantitative measurements, at a time resolution of five seconds, of molecular ions corresponding to diverse aerosol-phase species, by applying extractive electrospray ionization mass spectrometry (EESI-MS) to indoor air analysis for the first time, as part of the highly instrumented HOMEChem field study. We demonstrate how the complex spectra of EESI-MS are screened in order to extract chemical information and investigate the possibility of interference from gas-phase semivolatile species. During experiments that simulated the Thanksgiving US holiday meal preparation, EESI-MS quantified multiple species, including fatty acids, carbohydrates, siloxanes, and phthalates. Intercomparisons with Aerosol Mass Spectrometer (AMS) and Scanning Mobility Particle Sizer suggest that EESI-MS quantified a large fraction of OA. Comparisons with FIGAERO-CIMS shows similar signal levels and good correlation, with a range of 100 for the relative sensitivities. Comparisons with SV-TAG for phthalates and with SV-TAG and AMS for total siloxanes also show strong correlation. EESI-MS observations can be used with gas-phase measurements to identify co-emitted gas- and aerosol-phase species, and this is demonstrated using complementary gas-phase PTR-MS observations.
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Affiliation(s)
- Wyatt L Brown
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Douglas A Day
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Harald Stark
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
- Aerodyne Research, Inc., Billerica, MA, USA
| | - Demetrios Pagonis
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | | | - Xiaoxi Liu
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Derek J Price
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Erin F Katz
- Department of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, PA, USA
| | - Peter F DeCarlo
- Department of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, PA, USA
| | - Catherine G Masoud
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX, USA
| | - Dongyu S Wang
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX, USA
| | - Lea Hildebrandt Ruiz
- McKetta Department of Chemical Engineering, University of Texas, Austin, TX, USA
| | - Caleb Arata
- Department of Chemistry, University of California, Berkeley, CA, USA
| | | | - Allen H Goldstein
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | - Marina E Vance
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA
| | - Jose L Jimenez
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
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78
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Jakoobi M, Dardun V, Camp C, Thieuleux C. Co 2(CO) 8 as an efficient catalyst for the synthesis of functionalized polymethylhydrosiloxane oils and unconventional cross-linked materials. Catal Sci Technol 2021. [DOI: 10.1039/d1cy00191d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Co2(CO)8 was found to be an effective and structurally simple catalyst for the functionalization of polymethylhydrosiloxane into functional silicone fluids using terminal alkenes and into cross-linked silicone materials using unconventional tethers.
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Affiliation(s)
- Martin Jakoobi
- Laboratory of Catalysis, Polymerization, Processes and Materials
- CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon
- Université de Lyon
- Institut de Chimie de Lyon
- F-69616 Villeurbanne
| | - Vincent Dardun
- Laboratory of Catalysis, Polymerization, Processes and Materials
- CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon
- Université de Lyon
- Institut de Chimie de Lyon
- F-69616 Villeurbanne
| | - Clément Camp
- Laboratory of Catalysis, Polymerization, Processes and Materials
- CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon
- Université de Lyon
- Institut de Chimie de Lyon
- F-69616 Villeurbanne
| | - Chloé Thieuleux
- Laboratory of Catalysis, Polymerization, Processes and Materials
- CP2M UMR 5128 CNRS-UCB Lyon 1-CPE Lyon
- Université de Lyon
- Institut de Chimie de Lyon
- F-69616 Villeurbanne
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79
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A DFT Study on the Cyclization-Mechanism during Process of Thermal Vacuum Degradation for Poly(dimethylsiloxanes). Polym Degrad Stab 2020. [DOI: 10.1016/j.polymdegradstab.2020.109367] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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80
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Improved Production and Biophysical Analysis of Recombinant Silicatein-α. Biomolecules 2020; 10:biom10091209. [PMID: 32825281 PMCID: PMC7565869 DOI: 10.3390/biom10091209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/12/2020] [Accepted: 08/17/2020] [Indexed: 11/16/2022] Open
Abstract
Silicatein-α is a hydrolase found in siliceous sea sponges with a unique ability to condense and hydrolyse silicon–oxygen bonds. The enzyme is thus of interest from the perspective of its unusual enzymology, and for potential applications in the sustainable synthesis of siloxane-containing compounds. However, research into this enzyme has previously been hindered by the tendency of silicatein-α towards aggregation and insolubility. Herein, we report the development of an improved method for the production of a trigger factor-silicatein fusion protein by switching the previous hexahistidine tag for a Strep-II tag, resulting in 244-fold improvement in protein yield compared to previous methods. Light scattering and thermal denaturation analyses show that under the best storage conditions, although oligomerisation is never entirely abolished, these nanoscale aggregates of the Strep-tagged protein exhibit improved colloidal stability and solubility. Enzymatic assays show that the Strep-tagged protein retains catalytic competency, but exhibits lower activity compared to the His6-tagged protein. These results suggest that the hexahistidine tag is capable of non-specific catalysis through their imidazole side chains, highlighting the importance of careful consideration when selecting a purification tag. Overall, the Strep-tagged fusion protein reported here can be produced to a higher yield, exhibits greater stability, and allows the native catalytic properties of this protein to be assessed.
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81
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Bernales Sender FR, Castañeda Vía JA, Tay LY. Influence of different phosphoric acids before application of universal adhesive on the dental enamel. J ESTHET RESTOR DENT 2020; 32:797-805. [PMID: 32812329 DOI: 10.1111/jerd.12636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/12/2020] [Accepted: 07/18/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND There are different etching gels available, which have different composition, different pH, and different viscosity, and there is little information in the literature comparing all these products. OBJECTIVE To evaluate the mean microshear bond strength and morphological characteristics of tooth enamel by evaluating different phosphoric acids combined with a universal adhesive system. MATERIALS AND METHODS Eighty-four enamel samples were used, which were divided according to the acid conditioning: G1: Scotchbond Etchant (3M Oral Care), G2: Ultra-Etch (Ultradent), G3: Eco-Etch (IvoclarVivadent), G4: ETCH-37 with BAC (Bisco), G5: Etching gel (Densell), G6: Condac 37 (FGM), and G7: Scotchbond Universal Adhesive (3M Oral Care) in self-etch mode. For the adhesive procedure, Scotchbond Universal Adhesive was the one used as indicated the manufacturer's instructions, 0.9-mm-diameter resin cylinders were placed. The microshear bond strength test was performed after being stored for 24 hours in water. The morphological characteristics of tooth enamel were analyzed using the Raman confocal microscope alpha300RA. The analysis of variance (ANOVA) test and Tukey post-test were used to analyze the differences between the groups. RESULTS The mean microshear bond strength values obtained for groups 1, 4, 5 were significantly greater than groups 2, 3, 6 and 7 (p < .05). All groups presented demineralization after the application of the etching acid, and few signs of demineralization were evident in group 7. CONCLUSIONS Acid-etching with ETCH-37 with BAC, Etching gel, and Scotchbond Etchant improved the adhesive strength in the enamel using an universal adhesive, and acid-etching with Condac 37, Ultra-Etch, and Eco-Etch provides similar adhesive strength values to self-etch mode of universal adhesive. CLINICAL SIGNIFICANCE All acid etchants should be considered as different. The test confirms that enamel etching prior to the application of a universal adhesive system depends on the selected acid etchand product.
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Affiliation(s)
| | | | - Lidia Yileng Tay
- Facultad de Estomatología, Universidad Peruana Cayetano Heredia, Lima, Peru
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82
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Ren Z, da Silva G. Auto-Oxidation of a Volatile Silicon Compound: A Theoretical Study of the Atmospheric Chemistry of Tetramethylsilane. J Phys Chem A 2020; 124:6544-6551. [DOI: 10.1021/acs.jpca.0c02922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhonghua Ren
- Department of Chemical Engineering, The University of Melbourne, Parkville 3010, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, The University of Melbourne, Parkville 3010, Australia
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83
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Yang Y, Wang Y, Hou X, Lin Y, Yang L, Hou X, Zheng C. Can low-temperature point discharge Be used as atomic emission source for sensitive determination of cyclic volatile methylsiloxanes? Anal Chim Acta 2020; 1124:121-128. [PMID: 32534664 DOI: 10.1016/j.aca.2020.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/17/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Abstract
Despite of increased interest in the application of miniature microplasma atomic spectrometry for environmental analytical chemistry, the amenable element detection range is limited to some metal elements and carbon due to it low power consumption. In this work, the generation of silicon atomic emission (251.6 nm and 288.2 nm) from the organosiloxanes was found possible in a low-temperature, low-power, and compact point discharge. Consequence, a tiny point discharge silicon optical emission spectrometer (μPD-OES) was exploited, and used as a novel GC detector for the determination of various cyclic volatile methyl siloxanes (cVMSs). Under the optimized conditions, the developed system provided limits of detection (LODs) of 0.2 mg L-1, 0.04 mg L-1, 0.03 mg L-1 and 0.02 mg L-1 of Si for hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane, respectively. Meanwhile, relative standard deviations (RSDs) of better than 2.3% were obtained. In contrast to gas chromatography mass spectrometer, GC-μPD-OES significantly simplifies the experimental setup with low power consumption and a miniature configuration. As far as we know, this work reports for the first time that silicon atomic emission can be generated in such low temperature microplasma. The accuracy of this system was validated by determining cVMSs in five daily-used shampoo samples collected from retail store, providing satisfactory recoveries (84%-114%) and excellent agreement with values determined by GC-MS at the 95% confidence level.
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Affiliation(s)
- Yuan Yang
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Yao Wang
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Xiaoling Hou
- Chengdu Environmental Monitoring Center, Chengdu, Sichuan, 610072, China
| | - Yao Lin
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Lu Yang
- National Research Council Canada, Ottawa, Ontario, Canada, K1A 0R6
| | - Xiandeng Hou
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China
| | - Chengbin Zheng
- Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, China.
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84
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Fu Z, Xie HB, Elm J, Guo X, Fu Z, Chen J. Formation of Low-Volatile Products and Unexpected High Formaldehyde Yield from the Atmospheric Oxidation of Methylsiloxanes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7136-7145. [PMID: 32401014 DOI: 10.1021/acs.est.0c01090] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
With stricter regulation of atmospheric volatile organic compounds (VOCs) originating from fossil fuel-based vehicles and industries, the use of volatile chemical products (VCPs) and the transformation mechanism of VCPs have become increasingly important to quantify air quality. Volatile methylsiloxanes (VMS) are an important class of VCPs and high-production chemicals. Using quantum chemical calculations and kinetics modeling, we investigated the reaction mechanism of peroxy radicals of VMS, which are key intermediates in determining the atmospheric chemistry of VMS. L2-RSiCH2O2• and D3-RSiCH2O2• derived from hexamethyldisiloxane and hexamethylcyclotrisiloxane, respectively, were selected as representative model systems. The results indicated that L2-RSiCH2O2• and D3-RSiCH2O2• follow a novel Si-C-O rearrangement-driven autoxidation mechanism, leading to the formation of low volatile silanols and high yield of formaldehyde at low NO/HO2• conditions. At high NO/HO2• conditions, L2-RSiCH2O2• and D3-RSiCH2O2• react with NO/HO2• to form organic nitrate, hydroperoxide, and active alkoxy radicals. The alkoxy radicals further follow a Si-C-O rearrangement step to finally form formate esters. The novel Si-C-O rearrangement mechanism of both peroxy and alkoxy radicals are supported by available experimental studies on the oxidation of VMS. Notably, the high yield of formaldehyde is estimated to significantly contribute to formaldehyde pollution in the indoor environment, especially during indoor cleaning.
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Affiliation(s)
- Zihao Fu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Hong-Bin Xie
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Jonas Elm
- Department of Chemistry and iClimate, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Xirui Guo
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhiqiang Fu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta T6G2R3, Canada
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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85
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Grabitz E, Olsson O, Amsel AK, Rummel B, Mitzel NW, Kümmerer K. Abiotic and biotic degradation of five aromatic organosilicon compounds in aqueous media-Structure degradability relationships. JOURNAL OF HAZARDOUS MATERIALS 2020; 392:122429. [PMID: 32208309 DOI: 10.1016/j.jhazmat.2020.122429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/18/2020] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
Silicones have many applications and are produced in large quantities. Despite their potential toxicity, information on their environmental mineralisation is scarce. Therefore, we investigated a group of five organosilicon compounds (o-MeOC6H4SiMe3 (1), p-MeOC6H4SiMe3 (2), (p-MeOC6H4)2SiMe2 (3), o-Me2NC6H4SiMe3 (4) and p-Me2NC6H4SiMe3 (5)), recently developed to be 'benign by design' based on their readily degradable core structure. Five different degradability tests were performed, one assessing hydrolytic and two analysing biological and photolytic stability, respectively. All substances, except (p-MeOC6H4)2SiMe2 (3), hydrolysed within 24 h to 50% indicating that this is one of the major pathways of their primary elimination. In agreement with previous research, none of the substances was readily biodegradable. In contrast, 100% of p-Me2NC6H4SiMe3 (5) was primarily eliminated by photolytic and hydrolytic processes. The elimination rates of the other substances ranged from 7% to 64%. Irradiation at shorter wavelengths increased both the extent and speed of photodegradation. Eleven transformation products of p-Me2NC6H4SiMe3 (5) were detected, all of which were completely eliminated within 64 min of irradiation with a Hg lamp (200-400 nm). The insertion of an electron-donating group on the benzene ring like in p-Me2NC6H4SiMe3 (5) clearly enhanced photolytic degradability but further research is necessary to achieve truly biodegradable silicones.
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Affiliation(s)
- Elisa Grabitz
- Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Universitätsallee 1, 21335 Lüneburg, Germany.
| | - Oliver Olsson
- Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Universitätsallee 1, 21335 Lüneburg, Germany.
| | - Ann-Kathrin Amsel
- Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Universitätsallee 1, 21335 Lüneburg, Germany.
| | - Britta Rummel
- Lehrstuhl für Anorganische Chemie und Strukturchemie, Universität Bielefeld, Fakultät für Chemie, Universitätsstraße 25, 33615 Bielefeld, Germany.
| | - Norbert W Mitzel
- Lehrstuhl für Anorganische Chemie und Strukturchemie, Universität Bielefeld, Fakultät für Chemie, Universitätsstraße 25, 33615 Bielefeld, Germany.
| | - Klaus Kümmerer
- Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Universitätsallee 1, 21335 Lüneburg, Germany.
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86
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Zhang Y, Oshita K, Kusakabe T, Takaoka M, Kawasaki Y, Minami D, Tanaka T. Simultaneous removal of siloxanes and H 2S from biogas using an aerobic biotrickling filter. JOURNAL OF HAZARDOUS MATERIALS 2020; 391:122187. [PMID: 32062547 DOI: 10.1016/j.jhazmat.2020.122187] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 01/01/2020] [Accepted: 01/24/2020] [Indexed: 06/10/2023]
Abstract
The feasibility of simultaneous removal of siloxane and H2S from biogas was investigated using an aerobic biotrickling filter (BTF). The biodegradation of H2S in the BTF followed a first-order kinetic model and more than 95 % H2S was eliminated within a residence time of 0.3 min. The removal of decamethylcyclopentasiloxane (D5) increased with longer empty bed residence time (EBRT). The partition test and microbial community analysis further reveals that up to 52 % removal of D5 was reached mainly by the chemical-absorption in acid recycling liquid. Finally, D5 was converted into mixtures of dimethylsilanediol (DMSD) and hexamethyldisiloxane (L2) via ring-opening hydrolysis in acid liquid and ring-shrinking polyreaction using CH4 derived from biogas. These operational characteristics demonstrate that the abiotic removal of D5, in addition to biological removal of H2S in an aerobic BTF can significantly decrease the siloxane loading to the downstream siloxane removing units.
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Affiliation(s)
- Yuyao Zhang
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, C-cluster, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Kazuyuki Oshita
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, C-cluster, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto, 615-8540, Japan.
| | - Taketoshi Kusakabe
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, C-cluster, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Masaki Takaoka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, C-cluster, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Yu Kawasaki
- Ebara Jitsugyo Co., Ltd., Ginza, Chuo-ku, Tokyo, Japan
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87
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Liu YQ, Yu WW, Jiang H, Shang GQ, Zeng SF, Wang ZW, Hu CY. Variation of baking oils and baking methods on altering the contents of cyclosiloxane in food simulants and cakes migrated from silicone rubber baking moulds. Food Packag Shelf Life 2020. [DOI: 10.1016/j.fpsl.2020.100505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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88
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Wang N, Tan L, Xie L, Wang Y, Ellis T. Investigation of volatile methyl siloxanes in biogas and the ambient environment in a landfill. J Environ Sci (China) 2020; 91:54-61. [PMID: 32172982 DOI: 10.1016/j.jes.2020.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/06/2020] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
Landfill biogas is a potential alternative for fossil fuel, but the containing impurities, volatile methyl siloxanes (simplified as siloxanes), often cause serious problems in gas turbines when applied to generate electricity. In this research, a collecting and analyzing method based on solvent adsorption and purge and trap-gas chromatography-mass spectrometry was established to determine the siloxanes in biogas from a landfill in Jinan, China, and adjacent ambient samples, such as soil, air, and leachate of the landfill. The results showed that, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) accounted for 63% of total siloxanes; and without considering D4 and D5, the order of detected siloxanes in concentration was found relating to Gibbs free energies of molecules, namely that higher abundant siloxane (except for D4 and D5) usually had lower Gibbs free energy. Additionally, the mass ratio between D4 and octamethyltrisiloxane (L3) in the biogas varied with different garbage age in landfills, possibly revealing the breaking-down of larger siloxane molecules with time. The samples, which were collected from environmental samples adjacent to the landfill, such as soil, water, and air, presented much higher siloxane level than urban or rural area away from landfills. The current H2S scrubber of the landfill biogas could decrease the total siloxanes from 10.7 to 5.75 mg/m3 due to Fe2O3 and a refrigerant drier in a purification system and cyclic siloxanes were more easily removed than linear ones.
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Affiliation(s)
- Ning Wang
- School of Environmental Science and Engineering, Shandong Key Laboratory of Water Pollution Control and Resource Reuse, Shandong University, Jinan, 266237, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP(3)), Shanghai, 200433, China; School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, 250100, China.
| | - Li Tan
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, 250100, China
| | - Lianke Xie
- State Grid Shandong Electric Power Company, Electric Power Science Research Institute, Jinan, 250100, China
| | - Yu Wang
- Beijing Key Laboratory of Water Resources & Environment Engineering, China University of Geosciences (Beijing), Beijing, 100083, China.
| | - Timothy Ellis
- Department of Civil, Construction, and Environmental Engineering, Iowa State University, Iowa, USA
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89
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Wollenburg M, Bajohr J, Marchese AD, Whyte A, Glorius F, Lautens M. Palladium-Catalyzed Disilylation and Digermanylation of Alkene Tethered Aryl Halides: Direct Access to Versatile Silylated and Germanylated Heterocycles. Org Lett 2020; 22:3679-3683. [DOI: 10.1021/acs.orglett.0c01169] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Marco Wollenburg
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
- Department of Chemistry, Davenport Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Jonathan Bajohr
- Department of Chemistry, Davenport Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Austin D. Marchese
- Department of Chemistry, Davenport Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Andrew Whyte
- Department of Chemistry, Davenport Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Frank Glorius
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Mark Lautens
- Department of Chemistry, Davenport Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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90
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Papanastasiou DK, Bernard F, Burkholder JB. Trimethylchlorosilane, (CH
3
)
3
SiCl: OH reaction kinetics and infrared spectrum. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Dimitrios K. Papanastasiou
- Earth System Research LaboratoryChemical Sciences DivisionNational Oceanic and Atmospheric Administration Boulder Colorado
- Cooperative Institute for Research in Environmental SciencesUniversity of Colorado Boulder Colorado
| | - François Bernard
- Earth System Research LaboratoryChemical Sciences DivisionNational Oceanic and Atmospheric Administration Boulder Colorado
- Cooperative Institute for Research in Environmental SciencesUniversity of Colorado Boulder Colorado
| | - James B. Burkholder
- Earth System Research LaboratoryChemical Sciences DivisionNational Oceanic and Atmospheric Administration Boulder Colorado
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91
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Han W, Sun H, Zhang S, Zhao Q, Zhang X, Ma Y, Chen J, Li H. Hydroxyl radical oxidation of cyclic methylsiloxanes D4 ∼ D6 in aqueous phase. CHEMOSPHERE 2020; 242:125200. [PMID: 31683163 DOI: 10.1016/j.chemosphere.2019.125200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/22/2019] [Accepted: 10/22/2019] [Indexed: 06/10/2023]
Abstract
Cyclic methylsiloxanes (CMS) were listed as candidates of substances of very high concerns in 2018 by the REACH. These compounds can enter environmental waters, and potentially cause harmful effects to aquatic organisms and human beings. Until now, reaction mechanisms of these pollutants with hydroxyl radicals (HO) in aqueous phase were unknown. In this study, reaction mechanisms of three typical CMS (D4 ∼ D6) with HO in aqueous phase were investigated by employing both UV/H2O2 experiments and density functional theoretical calculations. Bimolecular reaction rate constants (kHO·) of D4 ∼ D6 with HO were determined as kHO·(D4) = 8kHO·(D5) = 12kHO·(D6) = 6.6 × 108 L mol-1 s-1. Half-lives of HO oxiding D4 ∼ D6 ranged from 12 to 140 days at [HO] = 10-15 mol L-1 in sunlit surface water, and were comparable to (D4, D5) or much shorter (D6) than hydrolytic half-lives. The reactivity to HO decreased with the increasing size of siloxane ring in aqueous phase, in an order totally opposite to that in gaseous phase. Calculation results indicated that HO oxidation of the three CMS proceeded spontaneously through an exothermic H-abstraction process at the first step. Water molecules participated into H-abstraction of CMS and caused energy barrier of D5 higher than that of D4. Thus, H-bonds formed by water molecules were responsible for the reverse reactivity of CMS in aqueous phase. This work provided basic evidences suggesting environmental persistence of CMS in aqueous phase completely different from that in gaseous phase.
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Affiliation(s)
- Wenjing Han
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China; Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Hongyu Sun
- School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China
| | - Siyu Zhang
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China.
| | - Qing Zhao
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Xuejiao Zhang
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Yuqin Ma
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun, 130022, China
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Haibo Li
- School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China
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92
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Headspace gas chromatography for the determination of volatile methylsiloxanes in personal care products. Anal Bioanal Chem 2020; 412:2537-2544. [PMID: 32062831 DOI: 10.1007/s00216-020-02478-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/23/2020] [Accepted: 01/31/2020] [Indexed: 10/25/2022]
Abstract
Most of the reported methods for the analysis of volatile methylsiloxanes focus on their environmental fate or possible health effects, aiming at trace level analysis by using direct injection gas chromatography. However, system contamination as carry over and side reactions at the injector are commonly reported in those cases. In this article, we explore the use of headspace gas chromatography combined with the total vaporization technique as an alternative to avoid such issues for the analysis of linear (L2-L5) and cyclic (D3-D5) volatile methylsiloxanes. The proposed method showed good linearity with R2 values higher than 0.9961 and no significant contribution (α = 0.05) of the intercept. The limit of detection was always below 0.11 μg/vial (0.0025% m/m). Finally, the method was applied to real samples like an adhesive remover, hair oil, shampoo, and cream. After simple sample pretreatment, recoveries higher than 86% were achieved. Graphical abstract.
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93
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King BM, Janechek NJ, Bryngelson N, Adamcakova-Dodd A, Lersch T, Bunker K, Casuccio G, Thorne PS, Stanier CO, Fiegel J. Lung cell exposure to secondary photochemical aerosols generated from OH oxidation of cyclic siloxanes. CHEMOSPHERE 2020; 241:125126. [PMID: 31683444 PMCID: PMC6941482 DOI: 10.1016/j.chemosphere.2019.125126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
To study the fate of cyclic volatile methyl siloxanes (cVMS) undergoing photooxidation in the environment and to assess the acute toxicity of inhaled secondary aerosols from cVMS, we used an oxidative flow reactor (OFR) to produce aerosols from oxidation of decamethylcyclopentasiloxane (D5). The aerosols produced from this process were characterized for size, shape, and chemical composition. We found that the OFR produced aerosols composed of silicon and oxygen, arranged in chain agglomerates, with primary particles of approximately 31 nm in diameter. Lung cells were exposed to the secondary organosilicon aerosols at estimated doses of 54-116 ng/cm2 using a Vitrocell air-liquid interface system, and organic gases and ozone exposure was minimized through a series of denuders. Siloxane aerosols were not found to be highly toxic.
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Affiliation(s)
- Benjamin M King
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Nathan J Janechek
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Nathan Bryngelson
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Andrea Adamcakova-Dodd
- Department of Occupational and Environmental Health, The University of Iowa, 145 N. Riverside Dr., Iowa City, IA, 52242, USA
| | - Traci Lersch
- RJ Lee Group, 350 Hochberg Road, Monroeville, PA, 15146, USA
| | - Kristin Bunker
- RJ Lee Group, 350 Hochberg Road, Monroeville, PA, 15146, USA
| | - Gary Casuccio
- RJ Lee Group, 350 Hochberg Road, Monroeville, PA, 15146, USA
| | - Peter S Thorne
- Department of Occupational and Environmental Health, The University of Iowa, 145 N. Riverside Dr., Iowa City, IA, 52242, USA
| | - Charles O Stanier
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA.
| | - Jennifer Fiegel
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA.
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94
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He S, Chen L, Cui J, Yuan B, Wang H, Wang F, Yu Y, Lee Y, Li T. General Way To Construct Micro- and Mesoporous Metal–Organic Framework-Based Porous Liquids. J Am Chem Soc 2019; 141:19708-19714. [DOI: 10.1021/jacs.9b08458] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Sanfeng He
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Lihan Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jing Cui
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Biao Yuan
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Hongliang Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Fang Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yi Yu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yongjin Lee
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Tao Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
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95
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Sakurai T, Imaizumi Y, Kuroda K, Hayashi TI, Suzuki N. Georeferenced multimedia environmental fate of volatile methylsiloxanes modeled in the populous Tokyo Bay catchment basin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 689:843-853. [PMID: 31280166 DOI: 10.1016/j.scitotenv.2019.06.462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/27/2019] [Accepted: 06/27/2019] [Indexed: 06/09/2023]
Abstract
We investigated the multimedia fate of decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in the densely populated catchment basin of Tokyo Bay, Japan, by using a georeferenced multimedia model. We estimated the daily per person consumption rate of these compounds in Japan according to literature. Emissions to the atmosphere accounted for almost all of the emissions of these compounds to the environment. The majority of these compounds was predicted to be distributed in the atmosphere (about 60%) and sediment (about 40%). The advective flows in and out of the atmosphere over the Tokyo Bay catchment basin dominated the flows of these compounds. The sewerage systems contributed considerably to the transport and fate of D5 and D6 in water. They transported these compounds from households to discharge outlets of sewage treatment plants (STPs), which in turn accounted for approximately one quarter of the emission of these compounds to rivers and to Tokyo Bay. The wastewater treatment plants also effectively removed these compounds from the wastewater. The overall persistence of D5 and D6 in the catchment basin was estimated to be 3.8-9.5 days. The horizontal distributions of these compounds were similar among environmental compartments; high concentrations were generally observed in populated areas. A sensitivity analysis demonstrated that the D5 discharge rate to Tokyo Bay excluding the direct discharge from STPs and the D5 mass in the river compartment were sensitive to changes of the organic-carbon-water partition coefficient. Comparison with the concentrations in rivers measured recently in the target area showed that the model captured overall trends of low to high concentrations in rivers. However, there was some variability and a bias toward underprediction. The model provided a better fit to measurements for D5 than for D6. One potential factor contributing to the bias toward underprediction was underestimation of the consumption rates.
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Affiliation(s)
- Takeo Sakurai
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
| | - Yoshitaka Imaizumi
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Keisuke Kuroda
- Fukushima Branch, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Tamura, Fukushima 963-7700, Japan; Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Takehiko I Hayashi
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Noriyuki Suzuki
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
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96
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Lee D, Park MK, Lee IS, Choi SD. Contamination characteristics of siloxanes in coastal sediment collected from industrialized bays in South Korea. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 182:109457. [PMID: 31349106 DOI: 10.1016/j.ecoenv.2019.109457] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Siloxanes have been used as chemical additives in various products since the 1940s. They are known to have potentially toxic effects, to be environmentally persistent, and to be bioaccumulative. Previous studies have reported high levels of siloxanes in various environmental matrices. In this study, 6 cyclic siloxanes (D4-D9) and 13 linear siloxanes (L3-L15) in coastal sediment collected from southeastern bays adjacent to industrial zones in South Korea (Busan, Ulsan, Jinhae, and Gwangyang) were analyzed. The contamination levels and spatial distribution of siloxanes in the coastal sediment samples were investigated, with the hazard quotients (HQs) for siloxanes evaluated using Monte Carlo simulation. Across all samples, the total concentration (Σ19) of siloxanes was in the range of 11.6-3877 (mean: 305; median: 133) ng/g dry weight (dw). The highest average concentration of Σ19 siloxanes was found in Busan (mean: 580; median: 233 ng/g dw), followed by Ulsan (mean: 316; median: 209 ng/g dw), Jinhae (mean: 266; median: 125 ng/g dw), and Gwangyang (mean: 33; median: 27 ng/g dw), all of which are suggested to be affected by both industrial and domestic activities. The highest contributions were from D5 (18%) and D6 (34%), followed by D9 (7.3%) and L11 (5.8%). The HQs for siloxanes were less than 1, indicating that there was no risk to benthic organisms in the study areas; however, further monitoring of various environmental matrices is required to fully assess the potential ecological risks.
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Affiliation(s)
- Danbi Lee
- School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Min-Kyu Park
- School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - In-Seok Lee
- Southeast Sea Fisheries Research Institute, National Institute of Fisheries Science (NIFS), Tongyeong, 53085, Republic of Korea
| | - Sung-Deuk Choi
- School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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97
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Rautiainen P, Hyttinen M, Ruokolainen J, Saarinen P, Timonen J, Pasanen P. Indoor air-related symptoms and volatile organic compounds in materials and air in the hospital environment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2019; 29:479-488. [PMID: 30474394 DOI: 10.1080/09603123.2018.1550194] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/15/2018] [Indexed: 06/09/2023]
Abstract
In this case study, hospital workers did suffer from symptoms related to the poor indoor air quality. To investigate reasons for symptoms MM40-survey and house inspection methods were performed. The study consisted of 49 operating rooms and 470 employees. MM-40 survey revealed that over 40% of the staff suffered from skin reactions, over 50% had upper respiratory tract symptoms and 25% suffered headaches. No reason for the staff's symptom could be found in the structural studies of workplaces. The mean air exchange rate of the rooms was 5.51/h. In total 61 materials and 49 indoor air samples were taken. The most frequently found compounds in the material samples were 2-ethyl-1-hexanol and aliphatic hydrocarbons. VOC emissions were high in some of the material samples and they presumably were the one reason for the workers' symptoms observed in some in of the rooms. However, indoor air VOC concentrations were low in most of the cases. According to the linear regression model emissions from flooring material couldn't explain the indoor air concentration of the VOCs. One reason for that was the high ventilation rates of the rooms, which presumably kept VOC levels in indoors low. In addition, VOC concentrations indoors were strongly related to the ongoing healthcare activities in the hospital.
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Affiliation(s)
| | - Marko Hyttinen
- b Department of Environmental and Biological Sciences, University of Eastern Finland , Kuopio , Finland
| | - Joonas Ruokolainen
- b Department of Environmental and Biological Sciences, University of Eastern Finland , Kuopio , Finland
| | - Pekka Saarinen
- c Turku University of Applied Sciences, Institute of Occupational Health , Turku , Finland
| | - Jussi Timonen
- d Turku University of Applied Sciences, Mittavat Oy , Pielavesi , Finland
| | - Pertti Pasanen
- b Department of Environmental and Biological Sciences, University of Eastern Finland , Kuopio , Finland
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98
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Aluko EO, Adejumobi OA, Fasanmade AA. Peristrophe roxburghiana leaf extracts exhibited anti-hypertensive and anti-lipidemic properties in L-NAME hypertensive rats. Life Sci 2019; 234:116753. [PMID: 31419445 DOI: 10.1016/j.lfs.2019.116753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/06/2019] [Accepted: 08/11/2019] [Indexed: 01/11/2023]
Abstract
AIMS Hypertension is a global disease that has been combating the world health for ages. Peristrophe roxburghiana (PR) is used in traditional medicine to treat hypertension and other ailments. The present study examined phytochemical constituents, antioxidant activities and GC-MS analysis of extracts of PR leaf and also evaluated their anti-hypertensive and anti-lipidemic effects in NG-nitro-L-arginine methyl ester (L-NAME) hypertensive rats. METHODS Wistar rats were grouped into two groups: control and hypertensive. Hypertension was induced in the hypertensive group by oral gavage of 60 mg/kg b.w of L-NAME for 3 weeks. After induction, the hypertensive group was randomly sub-grouped into hypertensive, hypertensive treated and hypertensive untreated groups. These were orally gavaged respectively with 60 mg/kg b.w of L-NAME, 60 mg/kg b.w/day of L-NAME +200 mg/kg b.w of different extracts of PR (aqueous, ethanolic and methanolic extracts) and 60 mg/kg b.w of L-NAME +20 mg/kg b.w ramipril for 3 weeks. The blood pressure was measured by tail-cuff method at the third and sixth weeks. KEY FINDINGS The results showed that the extracts of PR significantly decrease blood pressure, pro-atherogenic lipids and atherogenic ratios in L-NAME hypertensive rats. White blood cells count, neutrophil count and creatinine level were also effectively decreased by the extracts. Furthermore, the extracts increase serum nitric oxide (NO) level, anti-atherogenic lipid, glutathione level, lymphocyte and platelet count in the rats. SIGNIFICANCE Extracts of PR leaf decrease blood pressure and increase NO level in L-NAME hypertensive rats and also corrected the hyperlipidemia and inflammatory response arising from the reduction in NO bioavailability.
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Affiliation(s)
- Esther Oluwasola Aluko
- Physiology Department, Faculty of Basic Medical Sciences, University of Uyo, Uyo, Akwa-Ibom State, Nigeria.
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99
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Wiesenfeldt MP, Nairoukh Z, Dalton T, Glorius F. Selective Arene Hydrogenation for Direct Access to Saturated Carbo- and Heterocycles. Angew Chem Int Ed Engl 2019; 58:10460-10476. [PMID: 30701650 PMCID: PMC6697539 DOI: 10.1002/anie.201814471] [Citation(s) in RCA: 154] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Indexed: 01/08/2023]
Abstract
Arene hydrogenation provides direct access to saturated carbo- and heterocycles and thus its strategic application may be used to shorten synthetic routes. This powerful transformation is widely applied in industry and is expected to facilitate major breakthroughs in the applied sciences. The ability to overcome aromaticity while controlling diastereo-, enantio-, and chemoselectivity is central to the use of hydrogenation in the preparation of complex molecules. In general, the hydrogenation of multisubstituted arenes yields predominantly the cis isomer. Enantiocontrol is imparted by chiral auxiliaries, Brønsted acids, or transition-metal catalysts. Recent studies have demonstrated that highly chemoselective transformations are possible. Such methods and the underlying strategies are reviewed herein, with an emphasis on synthetically useful examples that employ readily available catalysts.
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Affiliation(s)
- Mario P. Wiesenfeldt
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstrasse 4048149MünsterGermany
| | - Zackaria Nairoukh
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstrasse 4048149MünsterGermany
| | - Toryn Dalton
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstrasse 4048149MünsterGermany
| | - Frank Glorius
- Organisch-Chemisches InstitutWestfälische Wilhelms-Universität MünsterCorrensstrasse 4048149MünsterGermany
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100
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Polysiloxanes as polymer matrices in biomedical engineering: their interesting properties as the reason for the use in medical sciences. Polym Bull (Berl) 2019. [DOI: 10.1007/s00289-019-02869-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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