Patent ID: 8058479
Filing Date: 2011-11-15
Classification: C07C

Abstract:
1. A method for purifying a crude acetone raw material containing low molecular weight impurities, using three columns in sequence comprising the steps of: a) feeding the crude acetone raw material into a first column; b) adding an alkaline reagent and an oxidative reagent into the first column to form high molecular weight impurities; c) removing a top fraction from the first column by distillation to form a first bottom fraction comprising an acetone mixture comprising high molecular weight impurities; d) feeding the first bottom fraction comprising the acetone mixture obtained in step c) to a second rectification column at a charge point on the column; e) optionally adding an alkaline reagent to the second column above the charge point of the bottom fraction fed in step d); f) separating a purified acetone from the high molecular weight impurities and removing the purified acetone as a top fraction by distillation in the second column, thereby forming a second bottom fraction comprising an acetone mixture comprising high molecular weight impurities; g) feeding the second bottom fraction comprising the acetone mixture obtained in step f) to a third rectification column at a charge point on the column; h) removing a top fraction from the third column by distillation to form a third bottom fraction comprising high molecular weight impurities; and i) returning the top fraction removed from the third column to the first column; wherein the second rectification column is operated at atmospheric pressure, and wherein the purified acetone has an acetaldehyde level of less than 5 ppm as measured by gas chromatography from a calibration curve obtained using acetaldehyde/acetone standards and a KT-Test time of greater than 11.0 hours, as measured by the SABIC KT-Test method.