Purification Of Terephthalic Acid By Supercritical Fluid Extraction

Abstract

A process for the purification of terephthalic acid comprising (1) contacting an impure terephthalic acid with an amount of supercritical fluid, at a temperature and pressure, and for a period of time, sufficient to dissolve the terephthalic acid and its impurities in said supercritical fluid and (2) allowing said solution of terephthalic acid and impurities in supercritical fluid to expand into a reaction chamber, whereby the supercritical fluid becomes gaseous and the terephthalic acid, freed of impurities, precipitates out as a solid.