Abstract: Propylene glycol methyl ether is produced by feeding a solution of a basic catalyst in methanol to a catalytic distillation column containing a heterogeneous basic catalyst defining a heterogeneous reaction zone, and feeding propylene oxide to the column. The methanol reacts with the propylene oxide according to a dual homogeneous catalytic reaction and heterogeneous catalytic reaction to form propylene glycol methyl ether, which is removed from the column as a bottoms product. Alternatively, methanol can be reacted with propylene oxide in a pre-reactor, to form propylene glycol methyl ether, and, when the temperature in the pre-reactor reaches about 100° C., the reaction products are transferred to the catalytic distillation column for further reaction.

Abstract: Propylene glycol monomethyl ether butyrates and their isomers are obtained by the esterification of propylene glycol monomethyl ether or its isomer with iso-butyric or n-butyric acid at an elevated temperature above 80.degree. C. in the presence of acidic catalyst and azeotropic agent. These compounds are rectified for removing acid residue and moisture in order to yield the desirable product having high purity.

Abstract: Propylene glycol monomethyl ether propionate compounds are obtained by the esterification of propylene glycol monomethyl ether with propionic acid at an elevated temperature above 80.degree. C. in the presence of acidic catalyst and azeotropic agent. The compounds are rectified for removing acid residue and moisture in order to yield the desirable product having high purity.

Abstract: A propylene glycol monomethyl ether propionate compound is obtained by the esterification of propylene glycol monomethyl ether with propionic acid at an elevated temperature above 80 .degree.C. in the presence of acidic catalyst and azeotropic agent. This compound is rectified for removing acid residue and moisture in order to yield the desirable product having high purity.