Hoechst Aktiengesellschaft

Other

Peter Trabold

Gerhard Luft

In a supported catalyst for the preparation of monocarboxylic anhydrides by carbonylation of the appropriate esters or ethers, where, in the supported catalyst, an organosilicon compound is bonded, as a polyfunctional coupling agent, on the one hand to a support material and on the other hand to a noble-metal compound from group VIII of the Periodic Table of the Elements, the coupling agent is a chelate-forming organosilicon compound of the general formula ##STR1## where X=Cl, Br or --OR.sup.2 ;

Supported catalyst for the preparation of monocarboxylic anhydrides

The process for the preparation of monocarboxylic anhydrides of the general formula (RCO).sub.2 O 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.degree. to 400.degree. C. and pressures from 1 to 150 bar.

Process for the preparation of monocarboxylic anhydrides

In the process for the preparation of monocarboxylic anhydrides of the general formula (RCO).sub.2 O by reacting a carboxylic acid ester of dialkyl ether of the general formula RCOOR or ROR, where 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 iodine or bromine or compounds thereof as reaction promoter, and in the presence of a supported catalyst, at temperatures of from 130.degree. to 400.degree. C. and pressures of from 1 to 150 bar, where, in the supported catalyst, an organosilicon compound is bonded, as a polyfunctional coupling agent, on the one hand to a support material and on the other hand to a noble-metal compound from group VIII of the Periodic Table, a chelate-forming organosilicon compound of the general formula ##STR1## is employed as the polyfunctional coupling agent, where X=Cl, Br or --OR.sup.2 ;

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Dieburg, Germany

Peter Trabold