PROCESS FOR REDUCING THE CONTENT OF TEREPHTHALALDEHYDE ACID METHYL ESTER IN DIMETHYL TEREPHTHALATE

摘要

1491737 Purification of dimethyl terephthalate CHEMISCHE WERKE HULS AG 18 Dec 1974 [20 Dec 1973] 54588/74 Addition to 1486320 Heading C2C The invention comprises a process for the purification of dimethyl terephthalate which comprises contacting the crude ester, which contains terephthalaldehyde acid methyl ester as impurity, with a supported palladium catalyst in the gas phase at a temperature of from 150‹ C. to 350‹ C. and at a pressure of dimethyl terephthalate of from 10 to 1000 mbars to effect conversion of at least the major part of the impurity to methyl benzoate. The reaction may be carried out in the presence of a carrier gas which is preferably water vapour.