PROCESS FOR SEPARATING MONOCHLOROACETIC ACID AND DICHLOROACETIC ACID VIA EXTRACTIVE DISTILLATION USING AN ORGANIC SOLVENT

摘要

The present invention pertains to a process for separating monochloroacetic acid and dichloroacetic acid from one another via extractive distillation using (a) an extractive agent that is chemically stable and has a BF3 affinity of between 65 kJ/mole and 110 kJ/mole and (b) an organic solvent that is either an acid with a lowest pKa of between 3.0 and 6.5 or a base with a BF3 affinity of between 40 kJ/mole and 75 kJ/mole with the proviso that said BF3 affinity is lower than the BF3 affinity of the extractive agent, said organic solvent being chemically stable, and having a boiling point at atmospheric pressure of at least 468K, comprising the steps of (i) contacting a mixture comprising monochloroacetic acid and dichloroacetic acid with the extractive agent, (ii) distilling the mixture obtained in step (i) to obtain a monochloroacetic acid stream and a stream comprising dichloroacetic acid and the extractive agent, (iii) subjecting the stream comprising dichloroacetic acid and the extractive agent to a regeneration step, wherein the organic solvent is contacted with the mixture comprising monochloroacetic acid and dichloroacetic acid of step (i), or wherein the organic solvent is contacted with the mixture obtained in step (i) prior to and/or during step (ii), or wherein the organic solvent is contacted with the stream comprising dichloroacetic acid and the extractive agent obtained in step (ii) prior to or during step (iii), or any combination thereof.