GB795614A - Purifying methyl ethyl ketone by distillation - Google Patents

Abstract

Crude methyl ethyl ketone, such as is obtained by oxidation of lower aliphatic hydrocarbons, is separated from admixture with lower alcohols and esters by distilling the mixture in a distillation column and introducing water into the column, at a point above that at which the mixture is introduced, at a rate such that the concentration of water in the liquid phase below the water-inlet is between 25 and 60 weight per cent, maintaining a head-temperature of 72-75 DEG C. and a base-temperature of 85-100 DEG C., whereby a cut containing the M.E.K. and the esters will pass overhead leaving behind substantially all the alcohols, and then subjecting the ketone-ester cut to a second extractive distillation using water as extractant at a columnconcentration of 75 to 96 weight per cent while maintaining a head-temperature of 70-72 DEG C. and a base-temperature of 80-100 DEG C., whereby the esters will pass overhead leaving behind an aqueous solution of the purified M.E.K. A mixture containing 43.4 weight per cent of M.E.K., 40.2 weight per cent of ethyl acetate and methyl propionate, 15,8 weight per cent of methanol, ethanol, propanols and butanols, and 0.6 weight per cent of other ketones is introduced into a distillation column; and water is supplied to an upper section of the column in such amount that the liquid phase in the column below the water-inlet contains 25 weight per cent of water. The column is operated at a reflux ratio of 5 to 1 with a head-temperature of 73.5 DEG C. and a base-temperature of 88 DEG C. The M.E.K. and the esters distil overhead, together with some water; and there is taken off at the base an aqueous mixture of the alcohols and the other ketones. The alcohols are separated from this mixture by distillation, and the water recovered is used in the extractive distillation column. The M.E.K. cut, obtained as overhead, contains 50.4 per cent M.E.K., 42 per cent esters and 5.6 per cent water, together with traces of alcohols. This cut is introduced into a distillation column, and water is introduced into an upper section so that the liquid phase in the column contains 95 per cent of water. The column is operated at a reflux ratio of 5 to 1 with a head-temperature of 70 DEG to 71 DEG C. and a base-temperature of 97 DEG C. The esters distil overhead together with some water; and there is taken off at the base an aqueous solution of purified M.E.K.