Improvements in or relating to the preparation of esters of a diaryl compound

摘要

The invention comprises esters of a diaryl carbinol dicarboxylic acid having an esterified carboxylic group attached to one or both of the aryl nuclei, and a process for preparing esters of a diaryl carbinol carboxylic acid or of a diaryl methane carboxylic acid, having an esterified carboxylic acid attached to one or both of the aryl nuclei comprising hydrogenating an ester of a diaryl ketone of the general formula: FORM:0973095/C1/1 where R1 and R2 are the same or different aryl radical containing one or more rings, at least one of which is an aromatic ring and at least one of which carries at least one esterified carboxylic group having from 2 to 20 carbon atoms, said aryl radicals carrying 0 to 4 radicals each of the type capable of substituting for hydrogen in an aryl nucleus, the hydrogenation being carried out at a temperature of at least 100 DEG C. and at a pressure of at least 21 kilogrammes per square centimetre for a time of at least 15 minutes with an amount of hydrogenation catalyst of at least 2% by weight of the diaryl ketone carboxylic acid ester and in the presence of a carrier which is an alcohol when the required product of hydrogenation is a diaryl carbinol carboxylic acid ester and a hydrocarbon when this product is a diaryl methane carboxylic ester, the amount of carrier used being at least 50% of the weight content of the charge ester. The aryl radicals may be phenyl, biphenyl, naphthyl, phenanthryl, anthryl, indyl, dihydronaphthyl or cyclohexylphenyl radicals, and the radicals capable of substituting for hydrogen in an aryl radical may be alkyl groups having from 1 to 16 carbon atoms or fluorine, chlorine, bromine or iodine atoms or amino or hydroxyl groups. If it is desired to avoid transesterification during hydrogenation, using an alcohol as carrier, the alcohol carrier employed must correspond to the ester grouping on the aromatic ring of the charge.