Preparation of alpha-beta-unsaturated c3-c6 carboxylic acids.

摘要

The present invention provides a process for the preparation of an alpha , beta -unsaturated C3-C6 carboxylic acid of greater than 98% purity, which combines fractional distillation and melt crystallization procedures. One embodiment of the process of the invention is depicted schematically in Figure 1 wherein 1 represents a dehydrogenation reactor in which a C3-C6 carboxylic acid is dehydrogenated to produce on alpha , beta -unsaturated C3-C6 carboxylic acid, 3 represents a distillation unit and 6 represents a melt crystallizer.