PROCESS FOR THE PREPARATION OF MONOCARBOXYLIC ANHYDRIDES

摘要

HOE 88/H 009 Process for the preparation of monocarboxylic anhydrides The process for the preparation of monocarboxylic anhydrides of the general formula (RCO)2O is carried out by reacting a carboxylic ester or a dialkyl ether of the general formula RCOOR or ROR, in which R in each case denotes the same alkyl radical having 1 to 4 carbon atoms, with carbon monoxide in the gas phase in the presence of a supported catalyst. The reaction takes place by means of bromine or iodine or compounds thereof as reaction promoter. The support material in the catalyst supports a noble metal chelate compound which is formed by a noble metal compound from group VIII of the periodic table and a chelating agent containing organonitrogen, organophosphorus, organoarsenic, organosulfur or mercapto groups and substituted in its basic structure with alkyl, aryl or aralkyl groups. The reaction is carried out at temperatures from 130 to 400.degree.C and pressures from 1 to 150 bar.