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Thermal decomposition of benzotrifluoride. The CC bond strength and the heat of formation of the phenyl radical
Author(s) -
Szilágyi I.,
Bérces T.
Publication year - 1970
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/kin.550020306
Subject(s) - chemistry , arrhenius equation , activation energy , thermal decomposition , decomposition , reaction rate constant , thermodynamics , radical , bond strength , homogeneous , kinetics , organic chemistry , physics , quantum mechanics , adhesive , layer (electronics)
Abstract The kinetics of the decomposition of benzotrifluoride was studied from 720°c to 859°c in a flow system with and without carrier gas. Consideration of the product distribution made possible the study of the decomposition into CF 3 and C 6 H 5 radicals, which appeared to be truly homogeneous in character. The first‐order rate constant of the CC bond fission, log k (sec −1 ) = (17.9 ± 0.5) (99.7 ± 2.5)/θ, did not change with change of initial concentration, pressure of the carrier gas, or contact time. The Arrhenius parameters have been related to the appropriate thermodynamic data. Assumption of 0 kcal/mole for the activation energy of the reverse combination reaction yielded D H 298 ° (C 6 H 5 CF 3 ) = 103.6 ± 2.5 kcal/mole and Δ H f 298 ° (C 6 H 5 ) = 77.1 ± 3.0 kcal/mole. Applicability of the simple first‐order formula to calculation of the rate constant has been also dealt with.