Patent ID: 8334397

Claim:
A process for producing a polyoxyethylene sorbitan fatty acid ester comprising reacting an ester (component A) of a fatty acid having 10 to 22 carbon atoms and a monohydric alcohol having 1 to 3 carbon atoms with at least either (component B) of sorbitol and sorbitan to obtain a sorbitan fatty acid ester and adding ethylene oxide to the sorbitan fatty acid ester, thereby producing a polyoxyethylene sorbitan fatty acid ester, which comprises: (a) a step of providing the component B in the form of a 50 to 90% by weight aqueous solution to mixing it with the component A, and performing dehydration until a water content in the system reaches 1.0% by weight or less based on a total weight of the components A and B; (b) a step of adding 1 to 10% by weight of a monohydric alcohol having 1 to 3 carbon atoms and 0.1 to 1.0% by weight of an alkali catalyst based on the total weight of the components A and B at 50 to 90° C.; (c) a step of performing a transesterification reaction under a nitrogen stream at a reaction temperature of 140 to 190° C. to obtain a sorbitan fatty acid ester; and (d) a step of adding ethylene oxide to the sorbitan fatty acid ester at a reaction temperature of 70 to 130° C.