Patent ID: 6821396
Filing Date: 2004-11-23
Classification: C07D,Y10S

Abstract:
A process for fractionating an amine-containing mixture comprising at least one amine, water, low-boilers and high-boilers, wherein said process comprises(i) separating off by distillation low-boilers from the amine-containing mixture, and (ii) separating of f by distillation high-boilers from the amine-containing mixture, to produce a pretreated amine-containing mixture, and (iii) extracting the pretreated amine-containing mixture with sodium hydroxide solution to form an aqueous, sodium-hydroxide-containing first phase and an aqueous-organic, amine-containing second phase, (iv) distilling the aqueous-organic second phase in a distillation column having an enrichment part and a stripping part to form an amine-water azeotrop and an essentially anhydrous amine, and recycling the amine-water azeotrop to the extraction step (iii), and wherein, in step (iv), the amine-water azeotrop is obtained as a sidestream takeoff in the enrichment part of the distillation column and is recycled to the extraction step (iii), and the essentially anhydrous amine is obtained as a sidestream takeoff in the stripping part of the distillation column, further low-boilers are obtained as an overhead takeoff and further high-boiler-containing amine is obtained as a bottom phase takeoff.