Separation of Anthracene from Crude Anthracene Using Gas Antisolvent Recrystallization

Abstract

Pure anthracene is mostly used for conversion to anthraquinone, an intermediate for the synthesis of very powerful vat dyestuffs. A coal tar distillate, crude anthracene, which contains 30% anthracene, 25% phenanthrane, 15% carbazole, and other impurities, was used as the model mixture. In this study, 90% by weight purity anthracene was obtained using gas antisolvent (GAS) recrystallization. The GAS process induces the separation of solids by introducing an antisolvent, carbon dioxide (or the supercritical fluid), into acetone which was used as the liquid solvent. The dissolution of the compressed gas into the solute-laden solution selectively lowers the solubilities of solid solutes and salts them out. The results showed that high purity anthracene was obtained at a high feed concentration and high pressure conditions. The separation factor of anthracene versus phenanthrene is close to 30.07.