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Kinetic stability of 1,1,1‐Trifluoroethane
Author(s) -
Tsang Wing,
Lifshitz Assa
Publication year - 1998
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/(sici)1097-4601(1998)30:9<621::aid-kin3>3.0.co;2-u
Subject(s) - chemistry , thermodynamics , shock tube , bar (unit) , kinetic energy , stability (learning theory) , tube (container) , range (aeronautics) , shock (circulatory) , shock wave , meteorology , classical mechanics , composite material , physics , machine learning , computer science , medicine , materials science
1,1,1‐Trifluoroethane has been decomposed in comparative rate single‐pulse shock‐tube experiments. The rate expression for elimination at ca. 2.5 bar and in the temperature range of 1050 to 1200 K has been found to be $$\it k\rm (CF_{3}\joinrel{\relbar\!\!\relbar}CH_{3}\relbar\!\!\rightarrow HF+CF_{2}=CH_{2})=7.0\times 10^{14}\ exp(-37260/T)s^{-1}$$ The experimental conditions appear to be such that the unimolecular reaction is at the beginning of the fall‐off region and we find that for step sizes down between 500 and 1000 cm −1 the high‐pressure rate expression is in the range $$\it k\rm (CF_{3}\joinrel{\relbar\!\!\relbar}CH_{3}\relbar\!\!\rightarrow HF+CF_{2}=CH_{2})=2.0\times 10^{15}\ exp(-38300/T)\ to\ 4\ \times\ 10^{15}\ exp(-39000/T)s^{-1}$$ where the smaller rate parameters refer to the larger step size down. The results are compared with those from an earlier study and the anomalously high A‐factor is noted. It is suggested that the existing rate expressions for the fluorinated ethanes may need to be reevaluated. © 1998 John Wiley & Sons, Inc., Int J Chem Kinet: 30: 621–628, 1998