Patent ID: 9035102
Filing Date: 2015-05-19
Classification: C07C,Y02P

Abstract:
1. A process for preparing isophorone, comprising: A) catalysed aldol condensation with acetone as a reactant; B) workup of the reaction product, the workup in stage B) being effected so as to give three fractions: a) a fraction composed of unconverted acetone, water and low boilers, which is condensed and then recycled into the reactor for reaction; b) a fraction in which colouring substances in particular are enriched, this fraction being purified further and the materials of value present being recycled into the process; c) a fraction composed of isophorone, more highly condensed products and water and catalyst, called material of value stream, this fraction subsequently being subjected to a first hydrolysis in which by-products are converted partly or fully to isophorone, acetone and other products of value; C) wherein the worked-up fraction c) is subjected to a phase separation into an essentially organic fraction d) and an essentially aqueous fraction e); D) distillative workup of the aqueous fraction e) and passage of the vapours from the top of the distillative workup apparatus onward into the hydrolysis apparatus of A); E) purification of the organic fraction d) to give the following three fractions: i) residue, ii) pure isophorone, iii) remaining low boilers; F) hydrolysis of the residue i) in a second hydrolysis and recycling of the products of value formed into the process.