Kinetics of the gas-phase reaction of CF3CF2CH2OH with OH radicals and its atmospheric lifetime

Abstract

CF 3 CF 2 CH 2 OH is a new chlorofluorocarbon (CFC) alternative. However, there are few data about its atmospheric fate. The kinetics of its atmospheric oxidation, the OH radical reaction of CF 3 CF 2 CH 2 OH, has been investigated in a 2-liter Pyrex reactor in the temperature range of 298 ϳ 356 K using gas chromatography (GC)-mass spectrometry (MS) for analysis in this study. The rate coefficient ofϪ0.76 s Ϫ1 was determined using the relative rate method. The results are in good agreement with the literature values and the prediction of Atkinson's structure-activity relationship (SAR) model. From these results, the atmospheric lifetime of CF 3 CF 2 CH 2 OH in the troposphere was deduced to be 0.34 year, which is 250 and 6 times shorter than those of CFC-113 and hydrochlorofluorocarbons (HCFC-225ca), respectively. Therefore CF 3 CF 2 CH 2 OH has significant potential for the replacement of CFC-113 and HCFC-225ca.

Table of Reaction Rate Constants of Photo‐Degradation Processes

“…[453]. 300) k OH measured f(T) 250-430K: A = 1.4E-12; E a = 6.49 kJ; k OH (298 K) = 1.0E-13; Chen et al 2000 [419]: f(T) 298-356 K: A = 2.27E-12; E a = 7.49 kJ; k OH (298 K) = 1.1E-13. The same authors measured the quantum effi ciency of acetaldehyde formation using the same wavelength to be Φ′ = 0.48.…”

An experimental and theoretical study on the reaction of Cl with CF3CF2CH2OH

“…A uniform distribution of CF 3 CF 2 CH 2 OH and global concentrations of Cl atoms (10 3 atom cm �3 [41]) and OH radicals (1 � 10 6 molecule cm �3 [42]) were assumed in the calculation of � by Equation (10). According to the calculated lifetimes (� Cl ¼ 50 years and � OH ¼ 4-5 months [9,12]), the tropospheric degradation of CF 3 CF 2 CH 2 OH initiated by Cl-reaction cannot compete globally with the corresponding OH-reaction.…”

“…Its reaction with OH radicals has been previously studied from an experimental [9][10][11][12] and theoretical [13] point of view. Nevertheless, there are only two experimental kinetic studies on the CF 3 CF 2 CH 2 OH þ Cl reaction [11,14].…”

Kinetics of Reactions of CHF2CF2CH2OH with Cl Atoms and CHF2CF2CHO with OH Radicals and Atmospheric Degradation Pathways of CHF2CF2CH2OH: A Theoretical Investigation

“…In recent times, hydrofluoroalcohols (HFAs) emerged as one such class of compounds that have been used as a potential replacement for CFCs, HCFCs and HFCs. They are known to have high chemical reactivity due to the presence of –OH group and zero ozone depletion potential (ODP) due to the absence of chlorine or bromine atoms . However, it is likely that the presence of C−F bonds in HFAs result in significant contribution to global warming potential (GWP) .…”