GB957003A - Improvements in the production of vinylene carbonate - Google Patents

Abstract

Vinylene carbonate is made in a continuous process by passing vapours of monochloroethylene carbonate over a catalyst comprising a metal of Group 1B, 2B or 8 or at least one oxide and/or chloride thereof supported on a carrier material, inert during the reaction; preferably of a particle size of 4-8 mm., suitably at temperatures of 270 DEG to 450 DEG C. though preferably at 300-400 DEG C. There may be used 0.2-0.5 moles of the catalytic material per litre of inert support. The preferred catalysts are chlorides of iron, cadmium, cobalt and copper. In an example monochloroethylene carbonate, diluted with nitrogen, is passed over a catalyst consisting of pumice granules which have been impregnated with cadmium chloride monohydrate and dried, in a stainless steel tube at temperatures between 300 DEG and 395 DEG C. Chloracetaldehyde is also formed in the reaction.ALSO:A catalyst for the dehydrochlorination of monochloroethylene carbonate comprises at least one metal of Sub-Group Ib or IIb or of Group VIII of the Mendel<\>aeeff Periodic System of elements or at least one chloride and/or oxide thereof and a carrier inert under the reaction conditions. Preferred catalysts contain one or more of the chlorides of iron, cobalt, copper, and cadmium. Suitable carrier materials are, for example, granulated pumice, Stuttgart composition or coke preferably in a grain size of 4-8 mm. 0,2-0,5 mole of the metals or salts may be applied per litre of the carrier. In an example, a catalyst is prepared by drying pumice of grain size 4-5 mm. after impregnation with a solution of cadmium chloride monohydrate.