HFO-1234ze(Z)热解机理的DFT研究
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摘要
通过密度泛函理论(DFT)对1,1,1,3-四氟丙烯(HFO-1234ze(Z),CF_3CH=CHF)的热解反应路径进行研究,对可能得热解产物(CF_3H,CF_4,HF)进行了分析。结果表明:在均裂反应中,CF_3自由基最易生成,其活化能为210.25 kJ mol~(-1)。相比之下,由于较高的活化能,F自由基最难产生。在随后的链式反应中,生成CF_3H所需的活化能最低为64.23kJ mol~(-1)。而生成CF_4和HF所需的活化能较高。本文从分子尺度研究了HFO-1234ze的热解机理并为研究有机工质的热稳定性提供了参考。
The reaction pathways of thermal decomposition of 1,1,1,3-tetrafluoro-1-propene(HFO-1234ze(Z), CF_3CH=CHF)were presented to investigate the formation mechanism of some possible products(CF_3H, CF_4, HF) by using density function theory(DFT) simulations. The results point out that CF_3 is the most preferred product in homolytic cleavage reaction with the lowest energy barrier of 210.25 kJ/mol. F radical is hard to be generated during thermal decomposition processes because of its higher energy barrier. In subsequent radical attacking chain reactions, a lower energy barrier(64.23 kJ/mol) is required to form CF_3H. CF_4 and HF will be generated with higher energy barriers.Our work presents the mechanism of thermal decomposition of HFO-1234 ze from a molecule level and provides a reference for studying the thermal stability of organic working fluids.
The reaction pathways of thermal decomposition of 1,1,1,3-tetrafluoro-1-propene(HFO-1234ze(Z), CF_3CH=CHF)were presented to investigate the formation mechanism of some possible products(CF_3H, CF_4, HF) by using density function theory(DFT) simulations. The results point out that CF_3 is the most preferred product in homolytic cleavage reaction with the lowest energy barrier of 210.25 kJ/mol. F radical is hard to be generated during thermal decomposition processes because of its higher energy barrier. In subsequent radical attacking chain reactions, a lower energy barrier(64.23 kJ/mol) is required to form CF_3H. CF_4 and HF will be generated with higher energy barriers.Our work presents the mechanism of thermal decomposition of HFO-1234 ze from a molecule level and provides a reference for studying the thermal stability of organic working fluids.
引文
[1]Tanaka K,Higashi Y,Thermodynamic Properties of HFO-1234yf(2,3,3,3-tetrafluoropropene)[J].International Journal of Refrigeration,2010,33(3):474-479
[2]Yamada N,Mohamad M N A,and Kien T T,Study on Thermal Efficiency of Low-to Medium-temperature Organic Rankine Cycles Using HFO-1234yf[J].Renewable Energy,2012,41:368-375
[3]HU Peng,CHEN Longxiang,ZHU Wanbao,et al.Isothermal VLE Measurements for the Binary Mixture of 2,3,3,3-tetrafluoroprop-l-ene(HFO-1234yf)+1,1-difluoroethane(HFC-152a)[J].Fluid Phase Equilibria,2014.373:80-83
[4]HU Peng,CHEN Longxiang,CHEN Zeshao.VaporLiquid Equilibria for Binary System of 2,3,3,3-tetrafluoroprop-l-ene(HFO-1234y f)+isobutane(HC-600a)[J].Fluid Phase Equilibria,2014.365:1-4
[5]Kamiaka T,Dang C,and Hihara E.Vapor-Liquid Equilibrium Measurements for Binary Mixtures of R1234jyf with R32,R125,and R134a[J].International Journal of Refrigeration,2013.36(3):965-971
[6]DAI Xiaoye,SHI Lin,AN Qingsong,et al.Chemical Kinetics Method for Evaluating the Thermal Stability of Organic Rankine Cycle Working Fluids.[J]Applied Thermal Engineering,2016,100:708-713
[7]Angelino G and Invernizzi C.Experimental Investigation on the Thermal Stability of Some New Zero ODP Refrigerants[J].International Journal of Refrigeration,2003.26(1):51-58
[8]Mishra B K,Chakrabartty A K,Deka R C.Theoretical Investigation of the Gas-phase Reactions of CF_2CIC(O)OCH3 with the Hydroxyl Radical and the Chlorine Atom at 298 K[J].Journal of Molecular Modeling,2013,19(8):3263-3270
[9]Mishra B K,Lily M,Chakrabartty A K,et al.Theoretical Investigation of Atmospheric Chemistry of Volatile Anaesthetic Sevoflurane:Reactions with the OH Radicals and Atmospheric Fate of the Alkoxy Radical(CF_)_2CHOCHFO:Thermal Decomposition vs.Oxidation[J].New Journal of Chemistry,2014,38(7):2813-2822
[10]Lily M,Mishra B K,Chandra A K.Kinetics,Mechanism and Thermochemistry of the Gas Phase Reactions of CF3CH_2OCH_2 CF3 with OH Radicals:a Theoretical Study[J].Journal of Fluorine Chemistry,2014,161:51-59
[11]Gour N K,Deka R C,Singh H J,et al.Theoretical Study on the Gas-phase Reactions of Ethyl Butyrate With OH Radicals at 298 K[J].Monatshefte fur Chemie-Chemical Monthly,2014,145(11):1759-1767
[12]LIU Chao,ZHANG Yayun,HUANG Xiaolu.Study of Guaiacol Pyrolysis Mechanism Based on Density Function Theory[J].Fuel Processing Technology,2014,123:159-165
[13]DU Benni,FENG Changjun,ZHANG Weichao.Theoretical Studies on the Reaction Mechanisms and Rate Constants for OH Radicals With CF3CFCH2[J].Chemical Physics Letters,2009,479(1):37-42
[14]QU Yena,SU Kehe,WANG Xin,et al.Reaction Pathways of Propene Pyrolysis[J].Journal of Computational Chemistry,2010,31(7):1421-1442
[2]Yamada N,Mohamad M N A,and Kien T T,Study on Thermal Efficiency of Low-to Medium-temperature Organic Rankine Cycles Using HFO-1234yf[J].Renewable Energy,2012,41:368-375
[3]HU Peng,CHEN Longxiang,ZHU Wanbao,et al.Isothermal VLE Measurements for the Binary Mixture of 2,3,3,3-tetrafluoroprop-l-ene(HFO-1234yf)+1,1-difluoroethane(HFC-152a)[J].Fluid Phase Equilibria,2014.373:80-83
[4]HU Peng,CHEN Longxiang,CHEN Zeshao.VaporLiquid Equilibria for Binary System of 2,3,3,3-tetrafluoroprop-l-ene(HFO-1234y f)+isobutane(HC-600a)[J].Fluid Phase Equilibria,2014.365:1-4
[5]Kamiaka T,Dang C,and Hihara E.Vapor-Liquid Equilibrium Measurements for Binary Mixtures of R1234jyf with R32,R125,and R134a[J].International Journal of Refrigeration,2013.36(3):965-971
[6]DAI Xiaoye,SHI Lin,AN Qingsong,et al.Chemical Kinetics Method for Evaluating the Thermal Stability of Organic Rankine Cycle Working Fluids.[J]Applied Thermal Engineering,2016,100:708-713
[7]Angelino G and Invernizzi C.Experimental Investigation on the Thermal Stability of Some New Zero ODP Refrigerants[J].International Journal of Refrigeration,2003.26(1):51-58
[8]Mishra B K,Chakrabartty A K,Deka R C.Theoretical Investigation of the Gas-phase Reactions of CF_2CIC(O)OCH3 with the Hydroxyl Radical and the Chlorine Atom at 298 K[J].Journal of Molecular Modeling,2013,19(8):3263-3270
[9]Mishra B K,Lily M,Chakrabartty A K,et al.Theoretical Investigation of Atmospheric Chemistry of Volatile Anaesthetic Sevoflurane:Reactions with the OH Radicals and Atmospheric Fate of the Alkoxy Radical(CF_)_2CHOCHFO:Thermal Decomposition vs.Oxidation[J].New Journal of Chemistry,2014,38(7):2813-2822
[10]Lily M,Mishra B K,Chandra A K.Kinetics,Mechanism and Thermochemistry of the Gas Phase Reactions of CF3CH_2OCH_2 CF3 with OH Radicals:a Theoretical Study[J].Journal of Fluorine Chemistry,2014,161:51-59
[11]Gour N K,Deka R C,Singh H J,et al.Theoretical Study on the Gas-phase Reactions of Ethyl Butyrate With OH Radicals at 298 K[J].Monatshefte fur Chemie-Chemical Monthly,2014,145(11):1759-1767
[12]LIU Chao,ZHANG Yayun,HUANG Xiaolu.Study of Guaiacol Pyrolysis Mechanism Based on Density Function Theory[J].Fuel Processing Technology,2014,123:159-165
[13]DU Benni,FENG Changjun,ZHANG Weichao.Theoretical Studies on the Reaction Mechanisms and Rate Constants for OH Radicals With CF3CFCH2[J].Chemical Physics Letters,2009,479(1):37-42
[14]QU Yena,SU Kehe,WANG Xin,et al.Reaction Pathways of Propene Pyrolysis[J].Journal of Computational Chemistry,2010,31(7):1421-1442