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The mechanism of cooxidation of isobutyraldehyde and octene‐2
Author(s) -
Montorsi G.,
Caprara G.,
Pregaglia G.,
Messina G.
Publication year - 1973
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.550050506
Subject(s) - isobutyraldehyde , chemistry , radical , decarboxylation , aldehyde , cyclopentane , epoxide , photochemistry , hydrogen atom abstraction , reaction mechanism , isobutane , reaction rate constant , chain termination , stereochemistry , organic chemistry , catalysis , kinetics , physics , polymer , radical polymerization , quantum mechanics , copolymer
The mechanism of isobutyraldehyde‐octene‐2 cooxidation at 20°C has been investigated. The ratio of cis to trans epoxides in the reaction products shows that, at aldehyde concentrations lower than 1.0 M , the epoxide is formed mainly by a radical route. The difference in the Δ H of formation of cis and trans epoxides is around 0.8 kcal/mole at 20°. The isobutyraldehyde involved in the radical epoxidation chain has been found almost quantitatively to be isopropylhydroperoxide, which is formed through the decarboxylation of i‐PrCO 2 · radicals, addition of oxygen, and abstraction of hydrogen atoms from the aldehyde. A rate constant of about 14 M −1 sec −1 at 20° has been determined for the latter reaction. The chain length for the cooxdination reaction decreases from 75 to 20 as the isobutyraldehyde concentration goes from 1.0 to 0.3 M . The termination step seems to involve mainly the interaction of two i‐PrO 2 · radicals. The cooxidation of octene‐2 with pivalaldehyde follows a similar mechanism, but the chain length is about ten times higher under the same experimental conditions.