Hoechst Aktiengesellschaft

G/u/ Nter Roscher

Friedrich Wunder

Hans-Joachim Schmidt

Hans Fernholz

Hans Krekeler

Heinz Schmitz

Hermann Neu

Unsaturated esters of carboxylic acids are prepared by reacting olefines or cycloolefines with carboxylic acids and oxygen in the gaseous phase in the presence of a catalyst containing noble metal salts or noble metals of the VIII.sup.th group of the Periodic System and alcali metal salts and/or alcaline earth metal salts, as activators the content of noble metal being in the range of from 1.2 to 5% by weight and the proportion of the metal fraction of each individual activator to the noble metal content being in the range of from 0.5 to 1 to 3:1.

Process for the manufacture of unsaturated esters of carboxylic acids

The invention relates to a process for the preparation of unsaturated aliphatic carboxylic acids by thermal cracking of the polymeric intermediate product ('polyester') which is formed in the catalytic reaction of aldehydes or ketones with ketene. The reaction mixture containing polyester is heated with water, and the polyester is then isolated and subjected to cracking. Or the polyester is first isolated and then heated with water and finally subjected to cracking. In both cases the temperature when the mixture is heated with water is the same as the boiling point, or is less than 40.degree. C. below the boiling point, of the aqueous mixture.

Process for the preparation of unsaturated aliphatic carboxylic acids

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Kelkheim, Germany

G/u/ Nter Roscher