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Synthesis and Characterization of ZnO-SiO 2 Composite Using Oil Palm Empty Fruit Bunch as a Potential Silica Source. Molecules 2021; 26:molecules26041061. [PMID: 33670482 PMCID: PMC7922681 DOI: 10.3390/molecules26041061] [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: 01/09/2021] [Revised: 02/06/2021] [Accepted: 02/11/2021] [Indexed: 11/16/2022] Open
Abstract
In this paper, the structural and optical properties of ZnO-SiO2-based ceramics fabricated from oil palm empty fruit bunch (OPEFB) were investigated. The OPEFB waste was burned at 600, 700 and 800 °C to form palm ash and was then treated with sulfuric acid to extract silica from the ash. X-ray fluorescence (XRF) and X-ray diffraction (XRD) analyses confirmed the existence of SiO2 in the sample. Field emission scanning electron microscopy (FESEM) showed that the particles displayed an irregular shape and became finer after leaching. Then, the solid-state method was used to produce the ZnO-SiO2 composite and the samples were sintered at 600, 800, 1000, 1200 and 1400 °C. The XRD peaks of the Zn2SiO4 showed high intensity, which indicated high crystallinity of the composite. FESEM images proved that the grain boundaries were larger as the temperature increased. Upon obtaining the absorbance spectrum from ultraviolet-visible (UV-Vis) spectroscopy, the energy band gaps obtained were 3.192, 3.202 and 3.214 eV at room temperature, 600 and 800 °C, respectively, and decreased to 3.127, 2.854 and 2.609 eV at 1000, 1200 and 1400 °C, respectively. OPEFB shows high potential as a silica source in producing promising optical materials.
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Yuan Z, Wen Y, Li G. Production of bioethanol and value added compounds from wheat straw through combined alkaline/alkaline-peroxide pretreatment. BIORESOURCE TECHNOLOGY 2018; 259:228-236. [PMID: 29567594 DOI: 10.1016/j.biortech.2018.03.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/08/2018] [Accepted: 03/09/2018] [Indexed: 06/08/2023]
Abstract
An efficient scheme was developed for the conversion of wheat straw (WS) into bioethanol, silica and lignin. WS was pre-extracted with 0.2 mol/L sodium hydroxide at 30 °C for 5 h to remove about 91% of initial silica. Subsequently, the alkaline-pretreated solids were subjected to alkaline hydrogen peroxide (AHP) pretreatment with 40 mg hydrogen peroxide (H2O2)/g biomass at 50 °C for 7 h to prepare highly digestible substrate. The results of enzymatic hydrolysis demonstrated that the sequential alkaline-AHP pretreated WS was efficiently hydrolyzed at 10% (w/v) solids loading using an enzyme dosage of 10 mg protein/g glucan. The total sugar conversion of 92.4% was achieved. Simultaneous saccharification and co-fermentation (SSCF) was applied to produce ethanol from the two-stage pretreated substrate using Saccharomyces cerevisiae SR8u strain. Ethanol with concentration of 31.1 g/L was produced. Through the proposed process, about 86.4% and 54.1% of the initial silica and lignin were recovered, respectively.
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Affiliation(s)
- Zhaoyang Yuan
- Department of Biochemistry & Molecular Biology, Michigan State University, 603 Wilson Road, East Lansing, MI 48824, USA.
| | - Yangbing Wen
- Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Guodong Li
- Key Lab of Pulp & Paper Science and Technology of Education Ministry of China, Qilu University of Technology, Jinan 250353, China
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Yuan Z, Wen Y, Kapu NS. Ethanol production from bamboo using mild alkaline pre-extraction followed by alkaline hydrogen peroxide pretreatment. BIORESOURCE TECHNOLOGY 2018; 247:242-249. [PMID: 28950132 DOI: 10.1016/j.biortech.2017.09.080] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/09/2017] [Accepted: 09/11/2017] [Indexed: 05/15/2023]
Abstract
A sequential two-stage pretreatment process comprising alkaline pre-extraction and alkaline hydrogen peroxide pretreatment (AHP) was investigated to convert bamboo carbohydrates into bioethanol. The results showed that mild alkaline pre-extraction using 8% (w/w) sodium hydroxide (NaOH) at 100°C for 180min followed by AHP pretreatment with 4% (w/w) hydrogen peroxide (H2O2) was sufficient to generate a substrate that could be efficiently digested with low enzyme loadings. Moreover, alkali pre-extraction enabled the use of lower H2O2 charges in AHP treatment. Two-stage pretreatment followed by enzymatic hydrolysis with only 9FPU/g cellulose led to the recovery of 87% of the original sugars in the raw feedstock. The use of the pentose-hexose fermenting Saccharomyces cerevisiae SR8u strain enabled the utilization of 95.7% sugars in the hydrolysate to reach 4.6%w/v ethanol titer. The overall process also enabled the recovery of 62.9% lignin and 93.8% silica at high levels of purity.
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Affiliation(s)
- Zhaoyang Yuan
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Yangbing Wen
- Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Nuwan Sella Kapu
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z4, Canada.
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Preda G, Rogobete AF, Săndesc D, Bedreag OH, Cradigati CA, Sarandan M, Papurica M, Popovici SE, Dragomirescu M. An in vitro study of the release capacity of the local anaesthetics from siloxane matrices. Rom J Anaesth Intensive Care 2017; 23:123-131. [PMID: 28913485 DOI: 10.21454/rjaic.7518/232.vit] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
AIMS In the field of anaesthesia and intensive care, the controlled release systems capable of delivering constantly local anaesthetics are of interest because of the advantages brought to pain management. In this paper we presented the release profiles by usage of siloxane matrices of two common local anaesthetics, lidocaine and bupivacaine, analysed in vitro. METHODS The siloxane matrices were obtained in accordance with the methods described in the specialized literature, tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS) were used as precursors. Lidocaine and bupivacaine were encapsulated in the synthesized gels. The controlled release was performed in vitro artificial systems in which temperature (30°C, 36.5°C, 40°C) and pH (6, 7, 8) have varied. RESULTS Following the analysis of the artificial systems similar profiles were highlighted for both local anaesthetics. Statistically significant differences were identified (p < 0.05) for systems where the release occurred at temperatures above 36.5°C. There were no statistically significant differences regarding the influence of pH, the type of the entrapped anaesthetic or the type of the precursor used in the synthesis of siloxane matrices. CONCLUSIONS According to this experimental study, the pH, the type of precursor or the type of anaesthetic does not statistically influence the release profile from the studied system. In conclusion, these systems are promising for obtaining pharmaceutical preparations which can be used in current clinical practice. Several studies on controlled release siloxane systems should be carried out both in vitro and in vivo in order to exclude possible toxicity and histopathological effects.
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Affiliation(s)
- Gabriela Preda
- Faculty of Chemistry, Biology, Geography, West University of Timisoara, Timisoara, Romania
| | - Alexandru Florin Rogobete
- Faculty of Chemistry, Biology, Geography, West University of Timisoara, Timisoara, Romania.,Faculty of Medicine, "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania.,Clinic of Anaesthesia and Intensive Care, Emergency County Hospital "Pius Brinzeu", Timisoara, Romania
| | - Dorel Săndesc
- Faculty of Medicine, "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania.,Clinic of Anaesthesia and Intensive Care, Emergency County Hospital "Pius Brinzeu", Timisoara, Romania
| | - Ovidiu Horea Bedreag
- Faculty of Medicine, "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania.,Clinic of Anaesthesia and Intensive Care, Emergency County Hospital "Pius Brinzeu", Timisoara, Romania
| | - Carmen Alina Cradigati
- Clinic of Anaesthesia and Intensive Care "Casa Austria", Emergency County Hospital "Pius Brinzeu", Timisoara, Romania
| | - Mirela Sarandan
- Clinic of Anaesthesia and Intensive Care "Casa Austria", Emergency County Hospital "Pius Brinzeu", Timisoara, Romania
| | - Marius Papurica
- Faculty of Medicine, "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania.,Clinic of Anaesthesia and Intensive Care, Emergency County Hospital "Pius Brinzeu", Timisoara, Romania
| | - Sonia Elena Popovici
- Faculty of Medicine, "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania
| | - Monica Dragomirescu
- Faculty of Animal Science and Biotechnology, Banat University of Agricultural Sciences and Veterinary Medicine, Timisoara, Romania
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Yuan Z, Wen Y. Evaluation of an integrated process to fully utilize bamboo biomass during the production of bioethanol. BIORESOURCE TECHNOLOGY 2017; 236:202-211. [PMID: 28411492 DOI: 10.1016/j.biortech.2017.03.179] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 06/07/2023]
Abstract
Aiming for the complete utilization of bamboo biomass, an integrated process which combines ethanol production with the recovery of silica and lignin was proposed. To reduce chemical charge required for the fractionation of silica and lignin from bamboo and improve the digestibility of the obtained substrate, a sequentially two-stage pretreatment process of autohydrolysis and alkaline extraction was carried out. From the view of enhancing enzymatic hydrolysis and recovery of silica and lignin, a two-stage treatment of autohydrolysis at 180°C for 90min followed by alkaline extraction at 100°C with 6% NaOH (based on pretreated chips) for 120min was optimized. About 93.7% of original silica and 75.7% of original lignin could be recovered from bamboo. Enzymatic hydrolysis and fermentation of carbohydrates showed that an overall sugar yield of 88.6% of original sugar content and an ethanol recovery of 0.467g/g sugar were achieved based on the proposed scheme.
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Affiliation(s)
- Zhaoyang Yuan
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z4, Canada.
| | - Yangbing Wen
- Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science and Technology, Tianjin 300457, China
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Sinyoung S, Kunchariyakun K, Asavapisit S, MacKenzie KJD. Synthesis of belite cement from nano-silica extracted from two rice husk ashes. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 190:53-60. [PMID: 28039819 DOI: 10.1016/j.jenvman.2016.12.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/14/2016] [Accepted: 12/06/2016] [Indexed: 06/06/2023]
Abstract
Nano-silicas extracted from a pure rice husk ash calcined in the laboratory (RHA) and ash from an impure industrial rice husk waste (BRHA), were used to form belite cement by firing with two different calcium sources (calcium carbonate and calcium nitrate). The nano-silica extracted from RHA was highly reactive due to its high pore volume and low activation energy of dehydration. The formation of belite cement from both nano-silicas was studied by firing with two different calcium sources, Ca(NO3)2 and CaCO3 at 800-1100 °C. Both nano-silicas formed the principal phase in belite cement (larnite or β-C2S) at temperatures as low as 800 °C, especially with calcium nitrate as the calcium source. Thus, highly impure BRHA is shown to be very suitable as a starting material for the low-temperature production of belite cement, especially in conjunction with calcium nitrate as the calcium source.
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Affiliation(s)
- Suthatip Sinyoung
- Division of Engineering, Mahidol University Kanchanaburi Campus, Kanchanaburi, Thailand.
| | | | - Suwimol Asavapisit
- School of Energy, Environment and Materials, King Mongkut's University of Technology Thonburi, Bangkok, Thailand.
| | - Kenneth J D MacKenzie
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Science, Victoria University of Wellington, Wellington, New Zealand
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Yuan Z, Wen Y, Kapu NS, Beatson R, Mark Martinez D. A biorefinery scheme to fractionate bamboo into high-grade dissolving pulp and ethanol. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:38. [PMID: 28203276 PMCID: PMC5303214 DOI: 10.1186/s13068-017-0723-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/02/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Bamboo is a highly abundant source of biomass which is underutilized despite having a chemical composition and fiber structure similar as wood. The main challenge for the industrial processing of bamboo is the high level of silica, which forms water-insoluble precipitates negetively affecting the process systems. A cost-competitive and eco-friendly scheme for the production of high-purity dissolving grade pulp from bamboo not only requires a process for silica removal, but also needs to fully utilize all of the materials dissolved in the process which includes lignin, and cellulosic and hemicellulosic sugars as well as the silica. Many investigations have been carried out to resolve the silica issue, but none of them has led to a commercial process. In this work, alkaline pretreatment of bamboo was conducted to extract silica prior to pulping process. The silica-free substrate was used to produce high-grade dissolving pulp. The dissolved silica, lignin, hemicellulosic sugars, and degraded cellulose in the spent liquors obtained from alkaline pretreatment and pulping process were recovered for providing high-value bio-based chemicals and fuel. RESULTS An integrated process which combines dissolving pulp production with the recovery of excellent sustainable biofuel and biochemical feedstocks is presented in this work. Pretreatment at 95 °C with 12% NaOH charge for 150 min extracted all the silica and about 30% of the hemicellulose from bamboo. After kraft pulping, xylanase treatment and cold caustic extraction, pulp with hemicellulose content of about 3.5% was obtained. This pulp, after bleaching, provided a cellulose acetate grade dissolving pulp with α-cellulose content higher than 97% and hemicellulose content less than 2%. The amount of silica and lignin that could be recovered from the process corresponded to 95 and 77.86% of the two components in the original chips, respectively. Enzymatic hydrolysis and fermentation of the concentrated and detoxified sugar mixture liquor showed that an ethanol recovery of 0.46 g/g sugar was achieved with 93.2% of hydrolyzed sugars being consumed. A mass balance of the overall process showed that 76.59 g of solids was recovered from 100 g (o.d.) of green bamboo. CONCLUSIONS The present work proposes an integrated biorefinery process that contains alkaline pre-extraction, kraft pulping, enzyme treatment and cold caustic extraction for the production of high-grade dissolving pulp and recovery of silica, lignin, and hemicellulose from bamboo. This process could alleviate the silica-associated challenges and provide feedstocks for bio-based products, thereby allowing the improvement and expansion of bamboo utilization in industrial processes.
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Affiliation(s)
- Zhaoyang Yuan
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z4 Canada
| | - Yangbing Wen
- Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science and Technology, Tianjin, 300457 China
| | - Nuwan Sella Kapu
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z4 Canada
| | - Rodger Beatson
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z4 Canada
- Chemical and Environmental Technology, British Columbia Institute of Technology, 3700 Willingdon Ave, Burnaby, V5G 3H2 Canada
| | - D. Mark Martinez
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z4 Canada
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Brigo L, Scomparin E, Galuppo M, Capurso G, Ferlin MG, Bello V, Realdon N, Brusatin G, Morpurgo M. Mesoporous silica sub-micron spheres as drug dissolution enhancers: Influence of drug and matrix chemistry on functionality and stability. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 59:585-593. [PMID: 26652411 DOI: 10.1016/j.msec.2015.10.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/30/2015] [Accepted: 10/12/2015] [Indexed: 11/17/2022]
Abstract
Mesoporous silica particles prepared through a simplified Stöber method and low temperature solvent promoted surfactant removal are evaluated as dissolution enhancers for poorly soluble compounds, using a powerful anticancer agent belonging to pyrroloquinolinones as a model for anticancer oral therapy, and anti-inflammatory ibuprofen as a reference compound. Mesoporous powders composed of either pure silica or silica modified with aminopropyl residues are produced. The influence of material composition and drug chemical properties on drug loading capability and dissolution enhancement are studied. The two types of particles display similar size, surface area, porosity, erodibility, drug loading capability and stability. An up to 50% w/w drug loading is reached, showing correlation between drug concentration in adsorption medium and content in the final powder. Upon immersion in simulating body fluids, immediate drug dissolution occurred, allowing acceptor solutions to reach concentrations equal to or greater than drug saturation limits. The matrix composition influenced drug solution maximal concentration, complementing the dissolution enhancement generated by a mesoporous structure. This effect was found to depend on both matrix and drug chemical properties allowing us to hypothesise general prediction behaviour rules.
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Affiliation(s)
- Laura Brigo
- Department of Industrial Engineering and INSTM Padova RU, University of Padova, via Marzolo 9, 35131 Padova, Italy; Micro System Technology RU, Center for Materials and Microsystems, Bruno Kessler Foundation, via Sommarive 18, 38123 Trento, Italy
| | - Elisa Scomparin
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, 35131, Padova, Italy
| | - Marco Galuppo
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, 35131, Padova, Italy
| | - Giovanni Capurso
- Helmholtz-Zentrum Geesthacht, Institute of Materials Research - Dept. of Nanotechnology, Max-Planck-Strasse 1, D-21502 Geesthacht, Germany
| | - Maria Grazia Ferlin
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, 35131, Padova, Italy
| | - Valentina Bello
- Department of Physics and Astronomy Galileo Galilei, University of Padova, via Marzolo 8, 35131 Padova, Italy
| | - Nicola Realdon
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, 35131, Padova, Italy
| | - Giovanna Brusatin
- Department of Industrial Engineering and INSTM Padova RU, University of Padova, via Marzolo 9, 35131 Padova, Italy
| | - Margherita Morpurgo
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, 35131, Padova, Italy.
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González Lazo MA, Blank M, Leterrier Y, Månson JAE. Superhard transparent hybrid nanocomposites for high fidelity UV-nanoimprint lithography. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Silica-coated calcium pectinate beads for colonic drug delivery. Acta Biomater 2013; 9:6218-25. [PMID: 23219846 DOI: 10.1016/j.actbio.2012.11.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 10/15/2012] [Accepted: 11/27/2012] [Indexed: 11/21/2022]
Abstract
The aim of this work is to develop novel organic-inorganic hybrid beads for colonic drug delivery. For this purpose, calcium pectinate beads with theophylline are prepared by a cross-linking reaction between amidated low-methoxyl pectin and calcium ions. The beads are then covered with silica, starting from tetraethyoxysilane (TEOS), by a sol-gel process. The influence of TEOS concentration (0.25, 0.50, 0.75 and 1.00 M) during the process is studied in order to modulate the thickness of the silica layer around the pectinate beads and thus to control the drug release. The interactions between the silica coating and the organic beads are weak according to the physicochemical characterizations. A good correlation between physicochemical and in-vitro dissolution tests is observed. At concentrations of TEOS beyond 0.25 M, the silica layer is thick enough to act as a barrier to water uptake and to reduce the swelling ratio of the beads. The drug release is also delayed. Silica-coated pectinate beads are promising candidates for sustained drug delivery systems.
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Liou TH, Lin HS. Synthesis and surface characterization of silica nanoparticles from industrial resin waste controlled by optimal gelation conditions. J IND ENG CHEM 2012. [DOI: 10.1016/j.jiec.2012.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Sandoval-Díaz LE, Coy-Barrera ED, Trujillo CA. Catalytic effect of fluoride on silica polymerization at neutral pH. REACTION KINETICS MECHANISMS AND CATALYSIS 2011. [DOI: 10.1007/s11144-011-0407-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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One-pot and efficient synthesis of triazolo[1,2-a]indazole-triones via reaction of arylaldehydes with urazole and dimedone catalyzed by silica nanoparticles prepared from rice husk. Molecules 2011; 16:9041-8. [PMID: 22031067 PMCID: PMC6264693 DOI: 10.3390/molecules16119041] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 10/13/2011] [Accepted: 10/20/2011] [Indexed: 11/17/2022] Open
Abstract
A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions and environmental friendliness.
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