Patent GB-788168-A (GB)
Title: New diarylmethane derivatives, their manufacture and application
Inventor: LAMBERT ARTHUR
IPC: C07C37/20
Filed: 1954-12-24
Abstract: The invention comprises bis-(2-hydroxy-3-a -alkyl cycloalkyl - 5 - ethylphenyl) - methanes in which the cycloalkyl groups may be the same or different and are cyclopentyl, methylcyclopentyl, cyclohexyl or methylcyclohexyl and the alkyl substituent has not more than 4 carbon atoms and is attached to the a -carbon atom of the cycloalkyl group, i.e. the carbon atom which is joined to the phenyl group.  The compounds are prepared by condensing 2 mols. of 2-a -alkylcycloalkyl - 4 - ethyl phenol with 1 mol. of formaldehyde or a substance yielding formaldehyde in the presence of acid, or by condensing 1 mol. of the above ethyl phenol derivative with 1 mol. of formaldehyde or a substance yielding it in the presence of a basic catalyst to form 2 - hydroxy - 3 - a  - alkylcycloalkyl - 5-ethylbenzyl alcohol or in the presence of HCl to form the corresponding benzyl chloride, the product obtained being condensed with 1 mol. of the same or different ethyl phenol derivative in the presence of acid. Alternatively, the benzyl alcohol derivative may be converted to the chloride with HCl before further condensation.  The 2 - a  - alkylcycloalkyl - 4 - ethyl phenol is prepared by condensing p-ethylphenol with an a  - alkylcyclopentene or hexene or a methyl-a - alkylcyclopentene or hexene in the presence of an acid condensing agent.  In examples: (1) p-ethylphenol and 1-methylcyclohexene are condensed in presence of H2SO4 to give 2 - a  - methylcyclohexyl - 4 - ethylphenol which is condensed with formaldehyde and HCl to give bis - (2 - hydroxy - 3 - a  - methylcyclohexyl - 5 - ethylphenyl) - methane; (2) in place of 1-methylcyclohexene there are used a -ethyl-, a  - n - butyl -, and a :d  - dimethyl - cyclohexenes and a -methylcyclopentene; (3) 2-a -methyl - cyclohexyl - 4 - ethylphenol is condensed with formaldehyde in presence of KOH and the 2 - hydroxy - 3 - a  - methylcyclohexyl-5-ethylbenzyl alcohol obtained is condensed with more of the same ethylphenol derivative; (4) the benzyl alcohol of (3) is treated with HCl to give the corresponding benzyl chloride before reaction with 2-a -methylcyclohexyl-4-ethylphenol phenol.  The compounds are used as antioxidants for synthetic rubber and polyethylene (see Group IV (a)), natural rubber (see Group V) and fats, oils and waxes (see Group III).  The Provisional Specification also describes the preparation of the compounds by reacting bis-(2 hydroxy - 5 - ethylphenyl) - methane with an a -alkyl-cyclopentene or hexene or a methyl-a -alkyl-cyclopentene or hexene in the presence of acid.ALSO:Antioxidants for fats, oils and waxes which tend to deteriorate in the presence of oxygen comprise bis - (2 - hydroxy - 3 - alkylcycloalkyl - 5 - ethylphenyl) - methanes in which the cycloalkyl groups, which may be the same or different, are cyclopentyl, methylcyclopentyl, cyclohexyl or methylcyclohexyl; the alkyl substituent has not more than 4 carbon atoms and is attached to the a -carbon atom of the cycloalkyl group, i.e. the carbon atom which is joined to the phenyl radical.ALSO:Antioxidants for polyethylene and synthetic rubbers, such as neoprene, polymers of butadiene-1 : 3 and iso-butene and copolymers of these compounds with acrylonitrile, styrene and methylmethacrylate, comprise bis-(2-hydroxy-3-a  - alkylcycloalkyl - 5 - ethylphenyl) - methanes in which the cycloalkyl groups which may be the same or different are cyclopentyl, methylcyclopentyl, cyclohexyl or methylcyclohexyl and the alkyl substituent has not more than 4 carbon atoms and is attached to the a -carbon atom of the cycloalkyl group, i.e. the carbon atom which is joined to the phenyl radical.  The antioxidants may be used in proportions of 1/4 to 2 per cent by weight of the rubber, and may be mixed with the rubber and vulcanizing and other ingredients before curing the mixture by heat treatment or mixed with other compounding ingredients and the mixture vulcanized with sulphur monochloride in the cold.  They may be used for stabilization of synthetic rubber prior to coagulation.  In an Example, (7), bis-(2 - hydroxy - 3 - a  - methylcyclohexyl - 5 - ethylphenyl)-methane is used as antioxidant in a mix containing neoprene, magnesium oxide, stearic acid, china clay, whiting, petroleum jelly, pale cumar resin, titanium oxide and zinc oxide.ALSO:Antioxidants for natural rubber comprise bis-(2-hydroxy-3-a -alkylcycloalkyl-5-ethyl-phenyl)-methanes in which the cycloalkyl groups which may be the same or different are cyclopentyl, methylcyclopentyl, cyclohexyl, or methylcyclohexyl and the alkyl substituent has not more than 4 carbon atoms and is attached to the a -carbon atom of the cycloalkyl group, i.e., the carbon atom which is joined to the phenyl radical.  The antioxidants may be used in proportions of 1/4 -2 per cent by weight of the rubber, and may be mixed with the rubber and vulcanizing and other ingredients before heat-curing or mixed with the other compounding ingredients before vulcanization with sulphur monochloride in the cold.  In examples, bis-(2-hydroxy - 3 - a  - methylcyclohexyl - 5 - ethyl - phenyl)-methane is used as antioxidant in mixes comprising (5) pale crepe natural rubber, zinc oxide, blanc fixe, stearic acid, sulphur and diphenylguanidine, (6) pale crepe natural rubber, zinc oxide, blanc fixe, stearic acid, titanium dioxide and zinc diethyldithiocarbamate, (8) aqueous dispersions of sulphur, zinc oxide, and zinc diethyldithiocarbamate, an aqueous solution of cetyl alcohol-ethylene oxide condensation product, and natural rubber latex.