GB942594A - Polyhydric phenols - Google Patents

Abstract

The invention comprises tetraphenols of the formula: <FORM:0942594/C2/1> where X and Y are alkyl groups and R is a hydrocarbon group and a method for the preparation of these compounds by reacting substantially four molecular equivalents of a phenol with a dialdehyde or a dialdehyde precursor in a solvent, for example an alcohol such as ethanol or a hydrocarbon such as benzene toluene or oxylene in the presence of an acidic catalyst e.g. zinc chloride or hydrogen chloride. The dialdehyde precursor may be a diacetal, e.g. 1:1:3:3tetraethoxypropane or a cyclic acetal e.g. 2ethoxy-3:4-dihydro-2H-pyran. The group R may be methylene, ethylene, trimethylene, o-, m- or p-phenylene, or 2:21-diphenylene and groups X and Y may be methyl, ethyl, isopropyl, t-butyl or t-octyl. Detailed examples are given of the preparation of 1:4-bis [di-(5-t-butyl-4hydroxy - 2 methyl - phenyl) - methyl] - benzene, 1:4 - bis [di - (4 - hydroxy - 2:5 - dimethylphenyl) methyl] benzene, 1:1:3:3 - tetra (5 - t - butyl 4 - hydroxy - 2 - methylphenyl) propane, 1:1:4:4 tetra (5 - t - butyl - 4 - hydroxy - 2 - methylphenyl) butane, 1:1:5:5 - tetra (5 - t - butyl - 4 - hydroxy2 - methylhenyl) pentane while brief reference is made to 1:1:4:4 - tetra (4 - hydroxy - 2:5 dimethylphenyl) butane and 1:1:5:5 - tetra (4 hydroxy - 2:5 - dimethyl phenyl) pentane. The compounds are used to stabilize hydrocarbon polymers (see Division C3). The Provisional Specifications refer also to compounds of the formula: <FORM:0942594/C2/2> wherein R is a hydrocarbon group, the hydroxyl groups are positioned ortho or para to the CH groups and wherein the nuclei A may carry alkyl and/or halogen groups as substituents.ALSO:Tetraphenols of the formula: <FORM:0942594/C3/1> where X and Y are alkyl groups and R is a hydrocarbon group are used to stabilise polyethylene and polypropylene. Sulphides or polysulphides may also be added to the polymer to increase the stabilizing effect of the tetraphenolic compounds. Sulphides mentioned are dialkyl sulphide e.g. dodecyl sulphide, di (substituted alkyl) sulphides, particularly esters of bis-carboxyalkyl sulphides e.g. tetra-n-hexyl ester of di(b :g -dicarboxy propyl) sulphide and dilauryl or dioctadecyl thiodipropionates or thiodibutyrates, dibenzyl sulphides e.g. bis(2-hydroxy-5-methylbenzyl)-sulphide and bis(3-tert-butyl-2-hydroxy-5-methoxy-benzyl) sulphide, diaryl sulphides e.g. diphenyl sulphides, dicresyl sulphides, 2:21-dihydroxy-5:51-dimethyl diphenyl disulphide, and diphenyldisulphide, dialkyldithio-phosphates such as bis(diisopropyl-dithiophosphory) disulphide and bis(dinonyl dithiophosphorylmethylene) thiourea, and dialkyldithiophosphatomethyl-phenols e.g. 4-methyl-2- (O:O1-dinonyldithiophosphatomethyl) phenol and 4-methyl-2:6-bis-(O:O1 - dinonyldithiophosphatomethyl) phenol. The stabilising effect of the mixture of tetraphenolic compounds and sulphides or polysulphides is enhanced, particularly when the polymer contains copper compounds or will come into contact with copper, by the addition of amines and amine derivatives. Amines and amine derivatives mentioned are 4:41-diaminodiphenylmethane, alkylene diamines, ethyleneimine polymers e.g. triethylene tetramine and diethylene triamine, N:N1-di (b -aminoethyl) piperazine, disalicylideneethylene diamine and mercaptbenzimidazole. The Provisional Specifications refer also to stabilizing polyethylene or polypropylene by the addition of a compound of the formula: <FORM:0942594/C3/2> wherein r is a hydrocarbon group, the hydroxyl groups are positioned ortho or para to the CH groups and wherein the nuclei A may carry alkyl and/or halogen group as substituents.