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Homogeneous decomposition of vinyl ethers. The heat of formation of ethanal‐2‐yl
Author(s) -
Rossi M.,
Golden D. M.
Publication year - 1979
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.550110705
Subject(s) - chemistry , homolysis , reaction rate constant , bond cleavage , thermal decomposition , activation energy , decomposition , homogeneous , radical , bond energy , medicinal chemistry , kinetics , thermodynamics , molecule , organic chemistry , catalysis , physics , quantum mechanics
The thermal unimolecular decomposition of three vinylethers has been studied in a VLPP apparatus. The high‐pressure rate constant for the retro‐ene reaction of ethylvinylether was fit by log k (sec −1 ) = (11.47 + 0.25) ‐ (43.4 ± 1.0)/2.303 RT at < T > = 900 K and that of t ‐ butylvinylether by log k (sec −1 ) = (12.00 ± 0.27) ‐ (38.4 ± 1.0)/2.303 RT at < T > = 800 K. No evidence for the competition of the higher energy homolytic bond‐fission process could be obtained from the experimental data. The rate constant compatible with the CO bond scission reaction in the case of benzylvinylether was log k (sec −1 ) = (16.63 ± 0.30) ‐ (53.74 ± 1.0)/2.303 RT at < T > = 750 K. Together with Δ H f ,300 0 (benzyl·) = 47.0 kcal/mol, the activation energy for this reaction results in Δ H f ,300 0 (CH 2 CHO) = +3.0 ± 2.0 kcal/mol and a corresponding resonance stabilization energy of 3.2 ± 2.0 kcal/mol for 2‐ethanalyl radical.