Patent ID: 6913674
Filing Date: 2005-07-05
Classification: C07D,Y10S

Abstract:
1. 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 off 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 azeotrope and an essentially anhydrous amine, and recycling the amine-water azeotrope to the extraction step (iii), and wherein, in step (iv), the amine-water azeotrope 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 bottom phase takeoff in the stripping part of the distillation column, and further low-boilers are obtained as an overhead takeoff.