PRODUCTION OF MONOCARBOXYLIC ACID ANHYDRATE

In a process for the preparation of monocarboxylic acid anhydrides of the general formula (RCO)2O, the reaction of a carboxylic acid ester or dialkyl ether of the general formula RCOOR or ROR, in which R in each case denotes the same alkyl radical having 1-4 C atoms, is carried out with carbon monoxide in the gas phase in the presence of a supported catalyst. The reaction is carried out using bromine or iodine or their compounds as reaction promoters. In the catalyst, the support material supports a noble metal chelate compound which is formed from a noble metal compound from group VIII of the Periodic Table and a chelater containing organonitrogen, organophosphorus, organoarsenic, organosulphur or mercapto groups, which is substituted in its fundamental structure by alkyl, aryl or aralkyl groups. The reaction is carried out at temperatures of 130 to 400 DEG C and pressures of 1 to 150 bar.