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Shaik RA, Jasper AW, Lynch PT, Sivaramakrishnan R, Tranter RS. Initiation and Carbene Induced Radical Chain Reactions in CH 2F 2 Pyrolysis. Chemphyschem 2024:e202400362. [PMID: 38714496 DOI: 10.1002/cphc.202400362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/01/2024] [Accepted: 05/07/2024] [Indexed: 05/10/2024]
Abstract
High temperature dissociations of organic molecules typically involve a competition between radical and molecular processes. In this work, we use a modeling, experiment, theory (MET) framework to characterize the high temperature thermal dissociation of CH2F2, a flammable hydrofluorocarbon (HFC) that finds widespread use as a refrigerant. Initiation in CH2F2 proceeds via a molecular elimination channel; CH2F2→CHF+HF. Here we show that the subsequent self-reactions of the singlet carbene, CHF, are fast multichannel processes and a facile source of radicals that initiate rapid chain propagation reactions. These have a marked influence on the decomposition kinetics of CH2F2. The inclusion of these reactions brings the simulations into better agreement with the present and literature experiments. Additionally, flame simulations indicate that inclusion of the CHF+CHF multichannel reaction leads to a noticeable enhancement in predictions of laminar flame speeds, a key parameter that is used to determine the flammability of a refrigerant.
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Affiliation(s)
- Rizwan A Shaik
- Department of Mechanical & Industrial Engineering, University of Illinois at Chicago, 842 W Taylor Street, Chicago, IL-60607, USA
| | - Ahren W Jasper
- Chemical Dynamics Group, Chemical Sciences & Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, IL-60439, USA
| | - Patrick T Lynch
- Department of Mechanical & Industrial Engineering, University of Illinois at Chicago, 842 W Taylor Street, Chicago, IL-60607, USA
| | - Raghu Sivaramakrishnan
- Chemical Dynamics Group, Chemical Sciences & Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, IL-60439, USA
| | - Robert S Tranter
- Chemical Dynamics Group, Chemical Sciences & Engineering Division, Argonne National Laboratory, 9700 S Cass Avenue, Lemont, IL-60439, USA
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2
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Sheldon DJ, Parr JM, Crimmin MR. Defluorination of HFCs by a magnesium reagent. Dalton Trans 2024; 53:6524-6528. [PMID: 38563682 PMCID: PMC11019403 DOI: 10.1039/d4dt00636d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 03/28/2024] [Indexed: 04/04/2024]
Abstract
Reaction of a series of HFCs with a main group reagent containing a Mg-Mg bond results in defluorination to form the corresponding magnesium fluoride complex. In the case of 1,1,1,2-tetrafluoroethane (HFC-134a) generation of the fluoride occurs alongside selective formation of 1,1-difluoroethene. DFT calculations have been carried out to better understand the selectivity and compare the barriers for sp3 C-F bond activation with sp3 C-H bond activation in this system.
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Affiliation(s)
- Daniel J Sheldon
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK.
| | - Joseph M Parr
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK.
| | - Mark R Crimmin
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK.
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3
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Seo J, Ukani R, Zheng J, Braun JD, Wang S, Chen FE, Kim HK, Zhang S, Thai C, McGillicuddy RD, Yan H, Vlassak JJ, Mason JA. Barocaloric Effects in Dialkylammonium Halide Salts. J Am Chem Soc 2024; 146:2736-2747. [PMID: 38227768 DOI: 10.1021/jacs.3c12402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Barocaloric effects─solid-state thermal changes induced by the application and removal of hydrostatic pressure─offer the potential for energy-efficient heating and cooling without relying on volatile refrigerants. Here, we report that dialkylammonium halides─organic salts featuring bilayers of alkyl chains templated through hydrogen bonds to halide anions─display large, reversible, and tunable barocaloric effects near ambient temperature. The conformational flexibility and soft nature of the weakly confined hydrocarbons give rise to order-disorder phase transitions in the solid state that are associated with substantial entropy changes (>200 J kg-1 K-1) and high sensitivity to pressure (>24 K kbar-1), the combination of which drives strong barocaloric effects at relatively low pressures. Through high-pressure calorimetry, X-ray diffraction, and Raman spectroscopy, we investigate the structural factors that influence pressure-induced phase transitions of select dialkylammonium halides and evaluate the magnitude and reversibility of their barocaloric effects. Furthermore, we characterize the cyclability of thin-film samples under aggressive conditions (heating rate of 3500 K s-1 and over 11,000 cycles) using nanocalorimetry. Taken together, these results establish dialkylammonium halides as a promising class of pressure-responsive thermal materials.
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Affiliation(s)
- Jinyoung Seo
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Rahil Ukani
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Juanjuan Zheng
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jason D Braun
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Sicheng Wang
- Department of Chemistry, University of North Texas, Denton, Texas 76203, United States
| | - Faith E Chen
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Hong Ki Kim
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Selena Zhang
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Catherine Thai
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Ryan D McGillicuddy
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Hao Yan
- Department of Chemistry, University of North Texas, Denton, Texas 76203, United States
| | - Joost J Vlassak
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jarad A Mason
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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4
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Guo B, Xie T, Zhang W, Wu H, Zhang D, Zhu X, Ma X, Wu M, Luo P. Rasterizing CO 2 emissions and characterizing their trends via an enhanced population-light index at multiple scales in China during 2013-2019. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167309. [PMID: 37742983 DOI: 10.1016/j.scitotenv.2023.167309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/31/2023] [Accepted: 09/21/2023] [Indexed: 09/26/2023]
Abstract
Climate change caused by CO2 emissions (CE) has received widespread global concerns. Obtaining precision CE data is necessary for achieving carbon peak and carbon neutrality. Significant deficiencies of existing CE datasets such as coarse spatial resolution and low precision can hardly meet the actual requirements. An enhanced population-light index (RPNTL) was developed in this study, which integrates the Nighttime Light Digital Number (DN) Value from the National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) and population density to improve CE estimation accuracy. The CE from the Carbon Emission Accounts & Datasets (CEADS) was divided into three sectors, namely urban, industrial, and rural, to differentiate the heterogeneity of CE in each sector. The ordinary least square (OLS), geographically weighted regression (GWR), temporally weighted regression (TWR), and geographically and temporally weighted regression (GTWR) models were employed to establish the quantitative relationship between RPNTL and CE for each sector. The optimal model was determined through model comparison and precision evaluation and was utilized to rasterize CE for urban, industrial, and rural areas. Additionally, hot spot analysis, trend analysis, and standard deviation ellipses were introduced to demonstrate the spatiotemporal dynamic characteristics of CE at multiple scales. The performance of the GTWR outperformed other methods in estimating CE. The enhanced RPNTL demonstrated a higher coefficient of determination (R2 = 0.95) than the NTL (R2 = 0.92) in predicting CE, particularly in rural regions where the R2 value increased from 0.76 to 0.81. From 2013 to 2019, high CE was observed in eastern and northern China, while a decreasing trend was detected in northeastern China and Chengdu-Chongqing. Conversely, the Yangtze River Delta, Pearl River Delta, Fenwei Plain, and Henan Province showed an increasing trend. The center of gravity for industrial and rural CE is shifting towards western regions, whereas that for urban CE is moving northward. This study provides valuable insights for decision-making on CE control.
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Affiliation(s)
- Bin Guo
- College of Geomatics, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
| | - Tingting Xie
- College of Geomatics, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China
| | - Wencai Zhang
- College of Land Science and Technology, China Agricultural University, Beijing 100193, China
| | - Haojie Wu
- College of Geomatics, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China
| | - Dingming Zhang
- College of Geomatics, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China
| | - Xiaowei Zhu
- Department of Mechanical and Materials Engineering, Portland State University, Portland, OR 97207, USA
| | - Xuying Ma
- College of Geomatics, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China
| | - Min Wu
- College of Geomatics, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China
| | - Pingping Luo
- School of Water and Environment, Chang'an University, Xi'an, Shaanxi 710054, China.
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5
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Li W, Han X, Li J, Lun X, Zhang M. Assessment of surface ozone production in Qinghai, China with satellite-constrained VOCs and NO x emissions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:166602. [PMID: 37659549 DOI: 10.1016/j.scitotenv.2023.166602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/05/2023] [Accepted: 08/25/2023] [Indexed: 09/04/2023]
Abstract
The implementation of the western development strategy of China and the migration of air pollutants from eastern China might lead to a rapid increase in volatile organic compounds (VOCs) concentrations in the Qinghai-Tibet Plateau (QTP) and an amplified role of Nitrogen Oxides (NOx) in ozone (O3) pollution. Qinghai province, situated on the northeast of the QTP, had fewer human activities compared to eastern China, while ozone pollution worsened over the years. To better capture recent emission trends and improve the accuracy of O3 simulation in Qinghai, this study proposed a top-down method, which combined the air quality modeling system RAMS-CMAQ, with formaldehyde (HCHO) and nitrogen dioxide (NO2) columns derived from TROPOMI as the constraints to improve the emission estimates of VOCs and NOx in July 2020, respectively. Through a series of sensitivity experiments, better quantified emission estimates of VOCs and NOx were obtained to be 1.33 and 0.34 Tg/yr, 2.5 and 2.1 times larger than the bottom-up ones. The results demonstrated the effectiveness of the top-down method and satellite observations constraints in improving VOCs and NOx emission estimates, resulting in a reduction in the differences between the observed and modeled HCHO and NO2 columns to 0.7 and 0.2 × 1015 molec/cm2, respectively. As a result, the simulated maximum daily 8-h average (MDA8) O3 concentrations increased from 58.9 to 81.6 μg/m3, which were closer to observations (85.4 μg/m3), the normalized mean bias (NMB) and normalized mean error (NME) values of hourly O3 concentrations changed from -24.7 % to -2.9 % and from 29.9 % to 22.3 %, respectively. This study showed the potential of top-down estimates to aide in the development of emission scenarios, which were critical for accurately simulating the O3 pollution and pollution control policy studies.
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Affiliation(s)
- Wen Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao Han
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jialin Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Xiaoxiu Lun
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Meigen Zhang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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6
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Wang Y, Liu L, Qiao X, Sun M, Guo J, Zhang J, Zhao B. Projections of National-Gridded Emissions of Hydrofluoroolefins (HFOs) in China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:8650-8659. [PMID: 37235871 DOI: 10.1021/acs.est.2c09263] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Hydrofluoroolefins (HFOs) are being used as substitutes for potent greenhouse gas hydrofluorocarbons (HFCs). However, the use and environmental impacts of HFOs are of great concern due to the rapid degradation of HFOs to produce persistent and phytotoxic trifluoroacetic acid (TFA). Here, we provide a comprehensive projection of HFO emissions in China during 2024-2060 for the first time. Under the Kigali Amendment to the Montreal Protocol, China's HFO emissions are estimated to increase from 1.7 (1.3-2.3) to 148.8 (111.4-185.4) kt in 2024-2060 with cumulative emissions of 2.8 (2.0-3.5) Gt, and cumulative reduced HFCs emissions are evaluated to be 5.4 Gt CO2-equivalent. High HFO emissions would be distributed mainly in the North China Plain and the eastern and coastal areas. HFO-1234yf (2,3,3,3-tetrafluoropropene) contributes most of HFO emissions with a cumulative emission of 1.7 Gt in 2024-2060, while the cumulative increment of TFA deposition from HFO-1234yf emissions would reach 0.4-1.0 Gt. The long-term national-gridded HFO emission inventories can provide scientific support for evaluating the environmental risks of HFOs and developing HFC phase-out pathways for addressing climate change.
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Affiliation(s)
- Yifei Wang
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Lu Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Xueqi Qiao
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Mei Sun
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Junyu Guo
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Jianbo Zhang
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Bu Zhao
- School for Environment and Sustainability and Michigan Institute for Computational Discovery and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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7
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Fratticioli C, Trisolino P, Maione M, Calzolari F, Calidonna C, Biron D, Amendola S, Steinbacher M, Cristofanelli P. Continuous atmospheric in-situ measurements of the CH 4/CO ratio at the Mt. Cimone station (Italy, 2165 m a.s.l.) and their possible use for estimating regional CH 4 emissions. ENVIRONMENTAL RESEARCH 2023:116343. [PMID: 37321340 DOI: 10.1016/j.envres.2023.116343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/21/2023] [Accepted: 06/05/2023] [Indexed: 06/17/2023]
Abstract
Methane (CH4) is an important climate forcer, contributing about 17% of the total radiative forcing by long living greenhouse gases. The Po basin is one of the most polluted and densely populated areas in Europe representing an important source region for CH4. The aim of this work was to test an inter-species correlation approach to derive estimates of anthropogenic CH4 emissions for the period 2015-2019 from the Po basin by combining CO bottom-up inventory data and continuous CH4 and CO observations from a mountain site in the northern Italy. The tested methodology suggested lower emissions in respect to EDGAR (-17%) and the Italian National Inventory (-40%) for the Po basin. However, despite the two bottom-up inventories, the emissions derived from the atmospheric observations reported an increasing tendency from 2015 to 2019 for the CH4 emissions. A sensitivity study revealed that using different subsets of the atmospheric observations implied a difference of 26% in the CH4 emission estimates. The highest agreement with two bottom-up CH4 inventories (EDGAR and the Italian national inventory) were obtained when atmospheric data were strictly selected for periods representative of air mass transport from the Po basin. Our study identified various challenges when using this methodology as a benchmark to verify bottom-up CH4 inventories. Issues could be attributed to the annual aggregation of the proxies used to derive the emission amounts, to the CO bottom-up inventory used as input information and to the relatively high sensitivity of the results to the different subsets of the atmospheric observations. However, the use of different bottom-up inventories as input data for CO emissions can potentially provide information that should be carefully considered for the purpose of integrating CH4 bottom-up inventories.
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Affiliation(s)
| | - P Trisolino
- CNR-ISAC, Via Gobetti 101, 40129, Bologna, Italy
| | - M Maione
- University of Urbino - Faculty of Science and Technologies, Piazza Rinascimento 6, Urbino, 61029, Italy
| | - F Calzolari
- CNR-ISAC, Via Gobetti 101, 40129, Bologna, Italy
| | - C Calidonna
- CNR-ISAC, Zona Industriale-Comparto 15-presso Fondazione Mediterranea Terina, I-88046, Lamezia Terme, CZ, Italy
| | - D Biron
- Aeronautica Militare, CAMM - Monte Cimone, Via delle Ville, 40 - 41029 Sestola, MO, Italy
| | - S Amendola
- Aeronautica Militare, CAMM - Monte Cimone, Via delle Ville, 40 - 41029 Sestola, MO, Italy
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Harders AN, Sturd ER, Wallisch L, Schmidt H, Mendoza-Apodaca Y, Corbin DR, White W, Junk CP, Shiflett MB. Solubility, Diffusivity, and Permeability of HFC-32 and HFC-125 in Amorphous Copolymers of Perfluoro(butenyl vinyl ether) and Perfluoro(2,2-dimethyl-1,3-dioxole). Ind Eng Chem Res 2023. [DOI: 10.1021/acs.iecr.2c04518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Affiliation(s)
- Abby N. Harders
- Institute for Sustainable Engineering, University of Kansas, Lawrence, Kansas 66045, United States
| | - Erin R. Sturd
- Institute for Sustainable Engineering, University of Kansas, Lawrence, Kansas 66045, United States
| | - Luke Wallisch
- Institute for Sustainable Engineering, University of Kansas, Lawrence, Kansas 66045, United States
| | - Hannes Schmidt
- Institute for Sustainable Engineering, University of Kansas, Lawrence, Kansas 66045, United States
| | | | - David R. Corbin
- Institute for Sustainable Engineering, University of Kansas, Lawrence, Kansas 66045, United States
| | - Whitney White
- Chromis Technologies, Warren, New Jersey 07059, United States
| | | | - Mark B. Shiflett
- Institute for Sustainable Engineering, University of Kansas, Lawrence, Kansas 66045, United States
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9
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Wei X, Wei Y, Lu J, Huang Y, Sun Y, Wang Y, Liu L, Liu B, Han W. Evolution of Lewis acidity by mechanochemical and fluorination treatment of silicon carbide as novel catalyst for dehydrofluorination reactions. MOLECULAR CATALYSIS 2023. [DOI: 10.1016/j.mcat.2023.112948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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10
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Fujihira Y, Iwasaki H, Sumii Y, Adachi H, Kagawa T, Shibata N. Continuous-Flow Synthesis of Perfluoroalkyl Ketones via Perfluoroalkylation of Esters Using HFC-23 and HFC-125 under a KHMDS–Triglyme System. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2022. [DOI: 10.1246/bcsj.20220162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yamato Fujihira
- Department of Engineering, Life Science and Applied Chemistry Program, Nagoya Institute of Technology, Gokiso-cho, Showa-Ku, Nagoya 466-8555, Japan
| | - Hiroto Iwasaki
- Department of Engineering, Life Science and Applied Chemistry Program, Nagoya Institute of Technology, Gokiso-cho, Showa-Ku, Nagoya 466-8555, Japan
| | - Yuji Sumii
- Department of Engineering, Life Science and Applied Chemistry Program, Nagoya Institute of Technology, Gokiso-cho, Showa-Ku, Nagoya 466-8555, Japan
| | - Hiroaki Adachi
- Tosoh Finechem Corporation, 4988, Kaiseicho, Shunan, 746-0006, Japan
| | - Takumi Kagawa
- Tosoh Finechem Corporation, 4988, Kaiseicho, Shunan, 746-0006, Japan
| | - Norio Shibata
- Department of Engineering, Life Science and Applied Chemistry Program, Nagoya Institute of Technology, Gokiso-cho, Showa-Ku, Nagoya 466-8555, Japan
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Gokiso-cho, Showa-Ku, Nagoya 466-8555, Japan
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11
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Sosulin IS, Feldman VI. Spectroscopy and radiation-induced chemistry of an atmospherically relevant CH 2F 2…H 2O complex: Evidence for the formation of CF 2…H 2O complex as revealed by FTIR matrix isolation and ab initio study. CHEMOSPHERE 2022; 291:132967. [PMID: 34800497 DOI: 10.1016/j.chemosphere.2021.132967] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/09/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
Difluoromethane is considered among the environment friendly alternatives to the ozone depleting chlorofluorocarbons. Due to its chemical inertness and lack of UV absorption above 200 nm, this compound can easily come to the upper layers forming complexes with widely abundant atmospheric components, such as water. The radiation-induced degradation of this compound and its complexes may be significant for reliable prediction of its long-term evolution in the environment as well as for development of new ways for its removal. In this work we have studied the vibrational spectroscopic properties and mechanisms of the radiation-induced decay of the CH2F2⋯H2O under the action of X-rays using matrix isolation FTIR spectroscopy and ab initio calculations. The IR spectrum of the complex in an argon matrix was characterized for the first time and assigned to a hydrogen-bonded structure with a binding energy of 11.1 kJ/mol (2.65 kcal/mol) (CCSD(T)/CBS level of theory). Complexation with water leads to a certain suppression of the efficiency of the radiation-induced decomposition of difluoromethane. The obtained results provide evidence for the radiation-induced formation of previously unreported CF2⋯H2O complex (in addition to other oxygen containing molecules, such as COF2 and CO). As demonstrated by calculations, the new difluorocarbene complex reveals a hydrogen bond and it is characterized by a binding energy of 5.73 kJ/mol (1.37 kcal/mol) (CCSD(T)/CBS level of theory).
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Affiliation(s)
- Ilya S Sosulin
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Vladimir I Feldman
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.
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12
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Barnes PW, Robson TM, Neale PJ, Williamson CE, Zepp RG, Madronich S, Wilson SR, Andrady AL, Heikkilä AM, Bernhard GH, Bais AF, Neale RE, Bornman JF, Jansen MAK, Klekociuk AR, Martinez-Abaigar J, Robinson SA, Wang QW, Banaszak AT, Häder DP, Hylander S, Rose KC, Wängberg SÅ, Foereid B, Hou WC, Ossola R, Paul ND, Ukpebor JE, Andersen MPS, Longstreth J, Schikowski T, Solomon KR, Sulzberger B, Bruckman LS, Pandey KK, White CC, Zhu L, Zhu M, Aucamp PJ, Liley JB, McKenzie RL, Berwick M, Byrne SN, Hollestein LM, Lucas RM, Olsen CM, Rhodes LE, Yazar S, Young AR. Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2021. Photochem Photobiol Sci 2022; 21:275-301. [PMID: 35191005 PMCID: PMC8860140 DOI: 10.1007/s43630-022-00176-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/14/2022] [Indexed: 12/07/2022]
Abstract
The Environmental Effects Assessment Panel of the Montreal Protocol under the United Nations Environment Programme evaluates effects on the environment and human health that arise from changes in the stratospheric ozone layer and concomitant variations in ultraviolet (UV) radiation at the Earth’s surface. The current update is based on scientific advances that have accumulated since our last assessment (Photochem and Photobiol Sci 20(1):1–67, 2021). We also discuss how climate change affects stratospheric ozone depletion and ultraviolet radiation, and how stratospheric ozone depletion affects climate change. The resulting interlinking effects of stratospheric ozone depletion, UV radiation, and climate change are assessed in terms of air quality, carbon sinks, ecosystems, human health, and natural and synthetic materials. We further highlight potential impacts on the biosphere from extreme climate events that are occurring with increasing frequency as a consequence of climate change. These and other interactive effects are examined with respect to the benefits that the Montreal Protocol and its Amendments are providing to life on Earth by controlling the production of various substances that contribute to both stratospheric ozone depletion and climate change.
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Affiliation(s)
- P W Barnes
- Biological Sciences and Environment Program, Loyola University New Orleans, New Orleans, USA
| | - T M Robson
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, Finland
| | - P J Neale
- Smithsonian Environmental Research Center, Edgewater, USA
| | | | - R G Zepp
- ORD/CEMM, US Environmental Protection Agency, Athens, GA, USA
| | - S Madronich
- Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, USA
| | - S R Wilson
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia
| | - A L Andrady
- Chemical and Biomolecular Engineering, North Carolina State University, Apex, USA
| | - A M Heikkilä
- Finnish Meteorological Institute, Helsinki, Finland
| | | | - A F Bais
- Laboratory of Atmospheric Physics, Department of Physics, Aristotle University, Thessaloniki, Greece
| | - R E Neale
- Population Health Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - J F Bornman
- Food Futures Institute, Murdoch University, Perth, Australia.
| | | | - A R Klekociuk
- Antarctic Climate Program, Australian Antarctic Division, Kingston, Australia
| | - J Martinez-Abaigar
- Faculty of Science and Technology, University of La Rioja, La Rioja, Logroño, Spain
| | - S A Robinson
- Securing Antarctica's Environmental Future, Global Challenges Program and School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia
| | - Q-W Wang
- Institute of Applied Ecology, Chinese Academy of Sciences (CAS), Shenyang, China
| | - A T Banaszak
- Unidad Académica De Sistemas Arrecifales, Universidad Nacional Autónoma De México, Puerto Morelos, Mexico
| | - D-P Häder
- Department of Biology, Friedrich-Alexander University, Möhrendorf, Germany
| | - S Hylander
- Centre for Ecology and Evolution in Microbial Model Systems-EEMiS, Linnaeus University, Kalmar, Sweden.
| | - K C Rose
- Biological Sciences, Rensselaer Polytechnic Institute, Troy, USA
| | - S-Å Wängberg
- Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - B Foereid
- Environment and Natural Resources, Norwegian Institute of Bioeconomy Research, Ås, Norway
| | - W-C Hou
- Environmental Engineering, National Cheng Kung University, Tainan, Taiwan
| | - R Ossola
- Environmental System Science (D-USYS), ETH Zürich, Zürich, Switzerland
| | - N D Paul
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - J E Ukpebor
- Chemistry Department, Faculty of Physical Sciences, University of Benin, Benin City, Nigeria
| | - M P S Andersen
- Department of Chemistry and Biochemistry, California State University, Northridge, USA
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - J Longstreth
- The Institute for Global Risk Research, LLC, Bethesda, USA
| | - T Schikowski
- Research Group of Environmental Epidemiology, Leibniz Institute of Environmental Medicine, Düsseldorf, Germany
| | - K R Solomon
- Centre for Toxicology, School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - B Sulzberger
- Academic Guest, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
| | - L S Bruckman
- Materials Science and Engineering, Case Western Reserve University, Cleveland, USA
| | - K K Pandey
- Wood Processing Division, Institute of Wood Science and Technology, Bangalore, India
| | - C C White
- Polymer Science and Materials Chemistry (PSMC), Exponent, Bethesda, USA
| | - L Zhu
- College of Materials Science and Engineering, Donghua University, Shanghai, China
| | - M Zhu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, China
| | - P J Aucamp
- Ptersa Environmental Consultants, Pretoria, South Africa
| | - J B Liley
- National Institute of Water and Atmospheric Research, Alexandra, New Zealand
| | - R L McKenzie
- National Institute of Water and Atmospheric Research, Alexandra, New Zealand
| | - M Berwick
- Internal Medicine, University of New Mexico, Albuquerque, USA
| | - S N Byrne
- Applied Medical Science, University of Sydney, Sydney, Australia
| | - L M Hollestein
- Department of Dermatology, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - R M Lucas
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
| | - C M Olsen
- Population Health Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - L E Rhodes
- Photobiology Unit, Dermatology Research Centre, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
| | - S Yazar
- Garvan Institute of Medical Research, Sydney, Australia
| | - A R Young
- St John's Institute of Dermatology, King's College London (KCL), London, UK
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13
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Talavera M, Braun T. Competing C-H and C-F bond activation reactions of a fluorinated olefin at Rh: a fluorido vinylidene complex as an intermediate in an unprecedented dehydrofluorination step. Chem Sci 2022; 13:1130-1135. [PMID: 35211279 PMCID: PMC8790890 DOI: 10.1039/d1sc06713c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 12/27/2021] [Indexed: 11/24/2022] Open
Abstract
The hydrofluoroolefin Z-1,3,3,3-tetrafluoropropene has been activated via an initial C-F bond activation and subsequent C-H bond activation using [Rh(H)(PEt3)3] (1) or via C-H bond activation at [Rh(CH3)(PEt3)3] (8). In both cases the formation of [Rh{(E)-CF[double bond, length as m-dash]CHCF3}(PEt3)3] (3) was observed. Importantly, the C-F activation product [Rh{(E)-CH[double bond, length as m-dash]CHCF3}(PEt3)3] (2) reacts in the presence of Z-1,3,3,3-tetrafluoropropene into 3. The latter converted into [Rh(C[triple bond, length as m-dash]CCF3)(PEt3)3] (6) by an unprecedented dehydrofluorination reaction, presumably via a vinylidene complex as intermediate. When the carbonyl complex [Rh(C[triple bond, length as m-dash]CCF3)(CO)(PEt3)3] (12) was treated with an excess of NEt3·3HF or HBF4 at low temperature, the formation of the phosphonioalkenyl compounds [Rh{(Z)-C(PEt3)[double bond, length as m-dash]CHCF3}(CO)(PEt3)2]X (X = F(HF) x , BF4) (13) was observed. The formation of 13 can be explained by an attack of PEt3 at the electrophilic α-carbon atom of an intermediate vinylidene complex. The employment of PiPr3 derivatives as model compounds allowed for the isolation of the unique fluorido vinylidene complex trans-[Rh(F)([double bond, length as m-dash]C[double bond, length as m-dash]CHCF3)(PiPr3)2] (16), which in the presence of PEt3 transforms into [Rh(C[triple bond, length as m-dash]CCF3)(PEt3)3] (6).
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Affiliation(s)
- Maria Talavera
- Department of Chemistry, Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
| | - Thomas Braun
- Department of Chemistry, Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
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