GB527402A - A process for the separation of an azeotropic vapour mixture containing alkyl phenols - Google Patents

Abstract

527,402. Purifying alkyl phenols by distillation. FIFE, J. G. (Naamlooze Vennootschap de Bataafsche Petroleum Maatschappij). April 11, 1939, No. 10992. [Class 32] [Also in Group IV] An azeotropic vapour mixture of steam, mercaptans, and alkyl phenols is separated into its constituents by a process which comprises cooling the mixture to produce a hot condensate composed of two liquid layers, a lower layer consisting essentially of water, an upper oily layer composed of mercaptans and alkyl phenols. The oily layer is fractionally distilled to produce an overhead mercaptan fraction having an end boiling point below the boiling temperature of the alkyl phenols present in the mixture, leaving a residual alkyl-phenol fraction which may contain a small amount of relatively high boiling mercaptans. An aqueous solution containing alkyl phenolates and mercaptans, such as is obtained in sweetening gasoline, is preheated and introduced into a column which is supplied at the base with live steam. The vapours leaving the head of the column are condensed at a temperature just below 100‹C. The hot condensate and uncondensed vapours are passed to a tank. The oily layer which separates in the tank is withdrawn, heated in a heater, and fractionated in a second column. Mercaptans and a small amount of water are taken off from the head of the second column; while the residual fraction, which comprises alkyl phenols and mercaptans boiling above 200‹C, is withdrawn at the base. The alkyl phenols so obtained may be blown with air to oxidize the residual mercaptans to disulphides. The alkyl phenols are then submitted to vacuum fractionation in a third column ; the purified alkyl phenols being taken overhead. The aqueous layer, from the decantation tank may be used to dilute the feed to the first column. Specification 519,397 is referred to.