Process for the Purification of cis-p-Coumaric Acid by Cellulose Column Chromatography after the Treatment of the trans Isomer with Ultraviolet Irradiation.

A methanolic solution of trans-p-coumaric acid was exposed to ultraviolet radiation and a mixture solution of the trans and cis isomers was subjected to cellulose column chromatography, eluting with an aqueous 0.1% trifluoroacetic acid solution containing methanol (90:10, v/v). Separation of the trans and cis isomers was achieved. The identity of the cis isomer was confirmed by TLC, HPLC, and NMR. Since both the support and eluent are inexpensive, the cis isomers can be obtained economically on both the laboratory and industrial scales.