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Reactions of radicals. XXVI. On the use of activation parameters as a test for concerted decomposition of initiators
Author(s) -
Pryor William A.,
Smith Kennedy
Publication year - 1971
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.550030502
Subject(s) - chemistry , decomposition , bond cleavage , radical , magnitude (astronomy) , bond , computational chemistry , organic chemistry , catalysis , physics , finance , economics , astronomy
In 1958, Bartlett and Hiatt [1] suggested that the number of bonds which are rotationally “frozen” at the transition state for decomposition of peresters can be determined from the magnitude of the values of Δ H ‡ and Δ S ‡ . In recent years, other workers have extended this hypothesis to include the use of the magnitude of Δ H ‡ and Δ S ‡ values to determine the number of bonds which undergo synchronous scission in the decomposition of initiators. This criterion for separating one‐bond from two ‐or three‐bond initiators is discussed in the light of all of the data now reported in the literature. It is probable that the correlation of Δ H ‡ and Δ S ‡ in an isokinetic plot cannot be used to distinguish either the number of bonds which are rotationally frozen at the transition state or the number that are undergoing scission, except in limited and rather imprecise ways. However, the insights and principles of Bartlett and Hiatt still are extremely useful as qualitative tools.