Hoechst Celanese Corporation

George E Beck

Siegbert Rittner

Donna L Keene

Volker Hautzel

Jack Chosnek

The present invention relates to a process for the purification of 4-acetoxystyrene from a crude product mixture comprising 4-acetoxystyrene and typically 5 or more contaminants in substantial amount. The crude product mixture is purified by melt crystallization by cooling the mixture to a temperature ranging from about +8.degree. C. to about -50.degree. C., whereby at least a first portion of the mixture is crystallized; removing the liquid remaining from contact with the crystallized first portion of the mixture; and, subsequently slowly heating the crystallized first portion, while simultaneously removing liquid which forms due to the heating, whereby impurities contained in the liquid which forms are removed from the crystallized first portion. Surprisingly, despite the large number of contaminants present, and use of the process to purify crude product mixtures containing as little as 50% by weight 4-acetoxystyrene, purities as high as 99.9% by weight have been obtained using multiple melt-crystallization steps of the process of the invention.

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Portland, TX, United States of America

George E Beck