Patent ID: 6695952
Filing Date: 2004-02-24
Classification: C07C,Y10S

Abstract:
A process for the separation and purification of an aqueous mixture comprising main components acetic acid, formic acid and high boilers, comprising the steps offeeding a raffinate stream containing a major part of water to a solvent stripping column (11) for removal of the water; conveying an extract stream to a solvent distillation column (8) having a top and a bottom and from which, in a first step, a mixture (A) comprising a major part of the solvent is separated off via the top and a mixture (B) comprising formic acid, water and solvent is separated off at a side offtake and a mixture (C) comprising acetic acid and high boilers is separated off via the bottom; feeding the mixture (B) to a formic acid distillation column (4) and feeding the mixture (C) to an acetic acid distillation column (5); and subsequently isolating purified acetic acid at a top of the acetic acid distillation column (5), isolating purified formic acid at a bottom of the formic acid distillation column (4) and at a top taking off a mixture of solvent and water which, together with the mixture (A) after separating off the water present, is recirculated to an extractor (7).