Patent GB-981043-A (GB)
Title: Phenolic antioxidants
IPC: C07C39/06
Filed: 1962-05-16
Abstract: Aralkyl phenols of formula <FORM:0981043/C2/1> wherein the R radicals, which may be the same or different, are hydrogen or alkyl radicals having from 1 to 9 carbon atoms, n is 0, 1 or 2 and x is 1, 2 or 3 with x-n positive, and alkylated cresols of formula <FORM:0981043/C2/2> wherein R is a tertiary alkyl radical of 4 to 12 carbon atoms and R1 is hydrogen or R, there being at least one tertiary alkyl radical attached to the phenolic ring in the position ortho to the hydroxy radicals, are prepared.  The aralkyl phenols are prepared by condensing a phenolic compound mixed with an acid catalyst and warmed with from 1 to 3 molecular equivalents of an arylalkene compound at below 150 DEG  C. and the catalyst destroyed by neutralization.  The alkylated cresols are prepared by alkylating ortho, meta or para cresol or a mixed cresol with at least one molar equivalent and preferably two molar equivalents, of a tertiary alkyl hydrocarbon containing from 4 to 12 carbon atoms in the presence of an acidic alkylation catalyst.  Examples of aralkyl phenols are the reaction products obtained by reacting phenol, styrene and isobutylene in the molar ratio of 1 : 2 : 1 or of 1 : 1 : 2 and the reaction products obtained by reacting phenol, vinyl toluene and isobutylene in the molar ratio 1 : 2 : 1 or 1 : 1 : 2, in the presence of an acidic alkylation catalyst, e.g. sulphuric acid. Specified compounds are 2-4-di - alphaphenyl - ethyl phenol, 2-6-dialphaphenylethyl - 4 - tertiary - butyl phenol, 2 - 4 - dimethyl - 6 - alphaphenylethyl phenol, 2 - alphaphenylethyl - 4 - methyl phenol, 2 - 4 - ditertiary - butyl - 6 - alphaphenylethyl phenol and 2 - 6 - ditertiary - butyl - 4 - alphatolylethyl phenol. Examples of tertiary - alkylated cresols are 2 - 6 - ditertiary - butyl - (3 or) 4 - methyl phenol, 6 - tertiary - butyl - 2 (or 3) - methyl phenol, 2 - 6 - ditertiary - amyl - 3 (or 4) - methyl phenol and the reaction products of m- or p-cresol and isobutene in 1 : 2 molar ratio.  Specification 870,192 is referred to.ALSO:Synthetic rubber polymers or copolymers of conjugated dienes are are stabilized by incorporating therein an antioxidant composition comprising (1) from 65 to 99 % of at least one aralkyl phenol of formula <FORM:0981043/C3/1> wherein the R radicals which may be the same or different are hydrogen or alkyl radicals of 1-9 carbonations, n is 0, 1 or 2 and x is 1, 2 or 3, x-n is positive, and/or at least one tertiary alkylated phenol of formula <FORM:0981043/C3/2> wherein n is 2 or 3 and n is 0, 1, 2 or 3 but not exceeding x and wherein R is tertiary butyl or tertiary amyl and R1 is tertiary octyl or tertiary nonyl, R and R1 being attached to the benzene nucleus in the 2, 4 or 6 positions and (2) from 35 to 1% of an alkylated cresol or cresol mixture of formula <FORM:0981043/C3/3> wherein R is a tertiary alkyl radical of from 4 to 12 carbon atoms and R1 is hydrogen or a tertiary alkyl radical of from 4 to 12 carbon atoms there being at least one tertiary alkyl radical attached to the phenolic ring in a position ortho to the hydroxyl radical.  Specified rubbers are cis-1-4-polyisoprene, cis-1.-4-polybutadiene butadiene-styrene, butadiene-acrylonitrile, polychloroprene, and butyl rubber. Specified aralkyl phenols are mono-, di- and tri-alphaphenylethyl phenols, mono-, di- and tri-alphatolylethyl phenols, mono-, di- and triphenylmethyl phenol and the corresponding mono- and di-cresols and mono-xylenols. Specified tertiary alkylated phenols include 2 - 4 - ditertiaryoctyl - 6 - tertiary - butyl phenol, and 2 - tertiaryoctyl - 4 - tertiarybutyl phenol while specified tertiary alkylated cresols include 2 - 6 - ditertiarybutyl - 4 - methylphenol and 2 - 4 - ditertiarybutyl - 3 - methyl phenol. Specification 870,192 is referred to.