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The azoethane‐initiated thermal reaction of isobutene. Heat of formation of the 2‐methyl‐2‐pentyl radical
Author(s) -
Seres L.,
Görgényi M.,
Farkas J.
Publication year - 1983
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.550151103
Subject(s) - chemistry , standard enthalpy of formation , methyl radical , radical , medicinal chemistry , photochemistry , organic chemistry
The azoethane‐sensitized thermal reaction of isobutene has been studied at 526–565 K. The initial concentrations of azoethane and isobutene were in the ranges of 1.40–10.5 × 10 −4 and 6.78–26.6 × 10 −4 mol/dm 3 , respectively. From the initial rates of formation of ethane and 2‐methylpentane the heat of formation of the 2‐methyl‐2‐pentyl radical was determined. The result obtained is ± H f 0 (2‐methyl‐2‐pentyl) = 0.8 ± 2.0 kcal/mol. The entropy of the radical, obtained from statistical mechanical calculations and experimentally, is S 0 (2‐methyl‐2 pentyl) = 92.8 ± 1.5 cal/mol°K. The results support the high heat of formation of the t ‐butyl radical suggested by different authors.