GB823544A - 2-hydroxy-4-alkoxy-4-alkylbenzophenones and compositions containing the same - Google Patents

Abstract

The invention comprises 2-hydroxy-4-alkoxy-41-alkylbenzophenones in which the alkyl and alkoxy groups each contain up to eight carbon atoms. The compounds may be prepared by a Friedel Crafts reaction with a para toluyl halide or other para-alkylbenzoyl halide having not more than eight carbon atoms in the alkyl group, and a resorcinol mono or dialkyl ether in which the alkyl groups contain one to eight carbon atoms. Substantially equimolecular quantities of the two reactants may be used. Resorcinol itself may also be employed as the second reactant in which case the product is a 2,4, dihydroxy 41-alkyl-benzophenone, which can then be alkylated with an alkylating agent having one to eight carbon atoms in the alkyl groups. The alkylation may be carried out in solution or suspension in aqueous alkali by heating with, for example, a dialkyl sulphate, such as dimethyl sulphate, or an alkyl para-toluene sulphonate, or an alkyl halide. Preferably an equimolar quantity of the two reactants or a slight excess of the alkylating agent is used. Examples are given of the preparation of 2 - hydroxy - 4 - methoxy - 41 methylbenzophenone from (1) para-toluyl chloride and resorcinol dimethyl ether, from (2) resorcinol, and para-toluyl chloride, using dimethyl sulphate as an alkylating agent; 2-hydroxy-4-ethoxy - 41 - methylbenzophenone from para-toluyl chloride and resorcinol diethyl ether. Other compounds mentioned are 2-hydroxy-4-methoxy - 41 - ethylbenzophenone, 2 - hydroxy-4 - ethoxy - 41 - ethylbenzophenone and 2 - hydroxy - 4 - n - butoxy - 41 - n - butylbenzophenone. Specification 789,070 is referred to.ALSO:The invention comprises 2-hydroxy-4-alkoxy-41-alkylbenzophenones in which the alkyl and alkoxy groups each contain up to eight carbon atoms for use as absorbers of ultra-violet light. Examples of these compounds are 2-hydroxy-4 - methoxy - 41 - methyl - benzophenone, 2 - hydroxy - 4 - methoxy - 41 - ethylbenzophenone, 2 - hydroxy - 4 - ethoxy - 41 - methylbenzophenone, 2 - hydroxy - 4 - ethoxy - 41 - ethylbenzophenone and 2 - hydroxy - 4 - n - butoxy41 - n - butylbenzophenone. Compositions resistant to the action of ultra-violet light comprise an organic polymeric material and at least one of the above defined compounds. The preferred polymeric materials are cellulose esters and ethers, homopolymers and copolymers of compounds containing a vinyl or vinylidene group such as styrene, vinyl chloride, vinyl acetate, vinyl butyrate, vinylidene chloride, alkyl esters of acrylic and methacrylic acids and compounds obtained by copolymerization of ethylenically unsaturated compounds containing a plurality of ester groups and compounds containing a vinyl group. Suitable amounts of 2 - hydroxy - 4 - alkoxy - 41 - alkylbenzophenones incorporated in the compositions are 0.05 to 0.5% of the weight of polymeric material, although amounts of 0.01 to 10% may be used. The benzophenones may be incorporated into cellulose esters or ethers together with plasticizers. The selected benzophenone may first be dissolved or dispersed in part or the whole of the plasticizer, which may then be incorporated with the ester or ether. Alternatively the benzophenone may be dissolved directly in whole or part of the cellulose derivative. Compositions of the benzophenones with vinyl polymers may be prepared by incorporating the benzophenone into the vinyl polymers during their formation. A free radical generating catalyst may be present. Examples are given of a composition of (1) polymerized methyl methacrylate or butyl methacrylate and 2 - hydroxy - 4 - methoxy - 41 - methylbenzophenone; (2) nitrocellulose lacquer and 2-hydroxy - 4 - methoxy - 41 - methylbenzophenone. Specification 789,070 is referred to.