GB1398855A - Recovery of styrene - Google Patents

Abstract

1398855 Distilling hydrocarbons HALCON INTERNATIONAL Inc 26 July 1972 [27 July 1971] 34976/72 Heading C5E Styrene is recovered from a mixture containing it and also alphaphenylethanol, styrene polymers, acetophenone and ethylbenzene by distillation in the presence of elemental sulphur as a polymerization inhibitor, and the amount of acetophenone present in the liquid phase is controlled so that the mole ratio of acetophenone to acetophenone plus alpha-phenylethanol is at least 0À4. The mixture may be that resulting from the oxidation of ethylbenzene to alpha-phenylethanol as principal product by dehydration to styrene. The high proportion of acetophenone suppresses the formation of volatile sulphur compounds by reaction between sulphur and alpha-phenylethanol, and is attained by adding acetophenone as a cutback oil or at any convenient point. In a typical embodiment, ethylbenzene and more volatile materials are removed in a first distillation, and styrene is separated from less volatile materials in a second distillation, in the presence of acetophenone which remains in the bottoms. There may be a third distillation of this residue to recover further styrene, and a fourth distillation to recover acetophenone and alpha-phenylethanol, leaving sulphur, polymers and tarry materials as residue. The acetophenone in the mixture can be hydrogenated and the mixture recycled to dehydrogenation, or the mixture can be separated and the acetophenone either hydrogenated or recycled to the distillation.