Exxonmobil Chemical Patents Inc.

Constantinos P Bokis

Javier Guzman

Monica D Lotz

Scott Jeffrey Weigel

Michael P Lanci

Catherine M Dorsi

Etienne Mazoyer

Processes are described for separating 3,4'- and 4,4&#x2032;-dimethylbiphenyl from a mixture comprising at least 3,3&#x2032;-, 3,4&#x2032;- and 4,4&#x2032;-dimethylbiphenyl. In the processes, the mixture is cooled to produce a crystallization product comprising at least of the 4,4&#x2032;-dimethylbiphenyl from the feed mixture and a first mother liquor product. The first mother liquor product is distilled to produce a bottoms stream enriched in 4,4&#x2032;-dimethylbiphenyl as compared with the first mother liquor product and an overhead stream deficient in 4,4&#x2032;-dimethylbiphenyl as compared with the first mother liquor product. The overhead stream is then cooled to produce a second crystallization product comprising at least part of the 3,4&#x2032;-dimethylbiphenyl from the overhead stream and a second mother liquor product.

Production and use of 3,4' and 4,4&#x2032;-dimethylbiphenyl isomers

Processes are described for purifying a biphenyldicarboxylic acid product containing one or more impurities, particularly at least formylbiphenylcarboxylic acid. In the processes, a mixture comprising the biphenyldicarboxylic acid product is contacted with hydrogen in the presence of a hydrogenation catalyst under conditions to selectively reduce at least part of the formylbiphenylcarboxylic acid to produce a hydrogenation effluent comprising (i) hydroxymethylbiphenylcarboxylic acid and/or methylbiphenylcarboxylic acid, and (ii) biphenylcarboxylic acid. At least a portion of the biphenyldicarboxylic acid is then separated from the hydrogenation effluent. Advantageously, a polyester product may be produced from the separated biphenyldicarboxylic acid.

Preparation and purification of biphenyldicarboxylic acids

Growing community of inventors

The Woodlands, TX, United States of America

Constantinos P Bokis