Atmospheric chemistry of trifluorodicarbonyls initiated by Cl atoms:Reactivity trends,mechanism,and acid formation yields  

作　　者：Pedro L.Lugo Vianni G.Straccia Cynthia B.Rivela Mariano A.Teruel María B.Blanco 

机构地区：[1]Laboratorio Universitario de Química y Contaminación del Aire(L.U.Q.C.A),Instituto de Investigaciones en Fisicoquímica de Córdoba(I.N.F.I.Q.C.),Dpto.de Fisicoquímica.Facultad de Ciencias Químicas,Universidad Nacional de Córdoba.Ciudad Universitaria,5000 Córdoba,Argentina [2]Institute for Atmospheric and Environmental Research,University of Wuppertal,DE-42097 Wuppertal,Germany

出　　处：《Journal of Environmental Sciences》2025年第5期12-25,共14页环境科学学报(英文版)

摘　　要：Rate coefficients of the gas-phase reactions of Cl atoms with a series of fluorinated diketones(FDKs):CF_(3)C(O)CH_(2)C(O)CH_(3)(TFP),CF_(3)C(O)CH_(2)C(O)CH_(2)CH_(3)(TFH)and CF_(3)C(O)CH_(2)C(O)CH(CH_(3))2(TFMH),have been measured at(298±2)K and under atmospheric pressure.The experiments were performed using the relative-rate method with a GC-FID detection system.From different determinations and references used,the following rate coefficients were obtained(in cm3/(molecule·sec)):k_(4)(TFP+Cl)=(1.75±0.21)×10^(−10),k_(5)(TFH+Cl)=(2.05±0.23)×10^(−10),k_(6)(TFMH+Cl)=(2.71±0.34)×10^(−10).Reactivity trends of FDKs were discussed and Free Energy Relationships analysis was developed.The expression lgkOH=1.68 lgkCl+5.71 was obtained for the reactivity of the studied FDKs together with similar unsaturated VOCs with Cl and OH radicals Additionally,acetic acid(CH_(3)C(O)OH)and trifluoroacetic acid(CF_(3)C(O)OH)were positively identified and quantified as degradation products using in situ FTIR spectroscopy.According to the identified products,atmospheric chemical mechanisms were proposed.The atmospheric implications of the studied reactions were assessed by the estimation of the tropospheric lifetimes of TFP,TFH,and TFMH concerning their reaction with Cl atoms to be 48,41,and 31 hours,respectively.The relatively short residence in the atmosphere of the fluorocarbons studied will have a local/regional impact with restricted transport.Global warming potential(GWP(20 yr))calculated for the studied fluoro diketones were 0.014,0.003 and 0.001 for TFP,TFH and TFMH,respectively with a negligible contribution to the greenhouse effect.

关 键 词：Fluorinated diketones Kinetics SPME-GC-FID FTIR in situ SAR Free energy relationships 

分 类 号：O62[理学—有机化学]