Method of preparation of 1,2- and 1,3- propanediol.

摘要

The invention relates to a method for the simultaneous preparation of 1,2- and 1,3-propanediol from glycerol. 1,2-Propanediol is customarily prepared from propylene oxide, 1,3-propanediol by hydration of acrolein with subsequent hydrogenation. The process according to the invention comprises the reaction stages (a) dehydration of glycerol by passing a gaseous glycerol/water mixture containing 10 to 40% by weight of glycerol at 250 to 340@C over a solid catalyst having an Ho value (Hammett's acid function) of less than 2, preferably between -3 and -8.2, (b) hydration of the acrolein contained in the reaction mixture of stage (a) and (c) catalytic hydrogenation of the reaction mixture containing the 3-hydroxypropionaldehyde and hydroxyacetone of stage (b). Two useful substances, namely 1,2- and 1,3-propanediol, can simultaneously be obtained in a high total yield from glycerol in a simple process.