method of preparing cyclic esters from five or six-carbon compounds comprising contacting a bed containing a solid acid catalyst with at least one of a five or six-carbon compound and method of preparing cyclic esters with compounds of five or six carbons comprising, in microwave irradiation, a liquid mixture of an inorganic acid catalyst, organic acid and at least one five or six carbon compound

摘要

Described herein are improved methods for the preparation of 5- and 6-membered cyclic mono and diesters of sugar alcohols and anhydrosugar alcohols by reaction with an organic acid RCOOH over a solid acidic substrate. The process is adaptable to a continuous process for simultaneously making and separating the cyclic esters from the sugar alcohols and anhydrosugar alcohols under mild conditions using the solid acid substrate as both the catalyst and a chromatographic bed for separation. The reactions are performed at mild temperatures of 70° C. to 100° C. and the formation of the cyclic esters is nearly quantitative. Also described is a method for making 5- and 6-membered cyclic mono and diesters of sugar alcohols and anhydrosugar alcohols using microwave irradiation in the presence of the organic acid.