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Chemistry on the decay of the phenoxy radical from butylated hydroxytoluene
Author(s) -
Omura Kanji
Publication year - 1992
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02540949
Subject(s) - chemistry , butylated hydroxytoluene , disproportionation , quinone methide , dimer , solvent , photochemistry , radical , dissociation (chemistry) , medicinal chemistry , solvent polarity , isomerization , catalysis , organic chemistry , polymer chemistry , quinone , antioxidant
Decay of unstable 2,6‐di‐ tert ‐butyl‐4‐methylphenoxy radical (2) was investigated in various solvents. Radical 2 was conveniently generated by dissociation of bis(methylcyclohexadienone) (1a), unstable dimer of 2, in solution. The products were butylated hydroxytoluene (3), 1,2‐bis(4‐hydroxyphenyl)ethane (7), 4,4′‐stilbenequinone (8), and 4‐(4‐hydroxybenzyl)cyclohexadienone (5). Unidentified products also were formed. The formation of 5 was favored in polar solvents, but was not subject to catalysis with Et 3 N or HCl. In contrast, the rates of formation of 7 and 8 appeared to be independent of solvent polarity. The mechanism of formation of the dimeric products via reactive intermediate quinone methide 4, generated from 2 by disproportionation, is discussed. Gradual disintegration of 5 in solution into 3 and 4 was investigated.