GB571661A - Dehydration of acetone - Google Patents

Abstract

571,661. Dehydration of acetone. SHELL DEVELOPMENT CO. May 10, 1943, No. 7401. Convention date, May 26, 1942. Drawings to Specification. [Class 32] Anhydrous acetone containing 0.3 per cent. water or less is obtained by submitting an aqueous mixture of acetone to fractional distillation in a fractionating zone maintained at a subatmospheric pressure. The process is preferably carried out on a mixture containing from about 1 to 50 per cent. by weight of water and the fractionating zone is preferably maintained at an absolute pressure between about 200 and 400 m.m. The mixture distilled may or may not contain other components, e.g., isopropyl alcohol. In the example an aqueous acetone mixture containing acetone and water in the weight ratio of about 2 to 1 was continuously distilled in a fractionating column provided with 49 plates. The absolute pressure in the column was about 300 m.m. When the reflux ratio was 1, the acetone product contained about 0.38 per cent. water. Increasing the reflux ratio to 2 resulted in an acetone containing only about 0.14 per cent. water. A still greater increase of the reflux ratio to 3 gave an acetone containing only about 0.04 per cent of water. The same material was distilled in the same apparatus, the pressure in the column being maintained at about 500 m.m. (absolute). Reflux ratios of 2, 3 and 4 resulted in an acetone distillate containing, respectively, 0.32, 0.18 and 0.09 per cent. of water. In each of the foregoing distillations the aqueous acetone mixture was introduced into the column at the fifteenth plate from the bottom.