METHOD FOR MONOCHLOROACETIC ACID AND DICHLOROACETIC ACID SEPARATION BY EXTRACTIVE DISTILLATION USING ORGANIC SOLVENT Russian patent published in 2017 - IPC C07C51/46 C07C51/44 C07C53/126 C07C43/275 C07C53/16 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of monochloroacetic acid and dichloroacetic acid separation from each other by extractive distillation using (a) an extracting agent, which is chemically stable and has an affinity for BF₃ between 65 kJ/mol and 110 kJ/mol, and (b) an organic solvent which is either an acid with the lowest pKa value between 3.0 and 6.5, or a base with an affinity for BF₃ between 40 kJ/mol and 75 kJ/mol, provided that the said affinity for BF₃ is lower than the extractant agent affinity for BF₃, at that, said organic solvent is chemically stable and has a boiling point of at least 468°K (195°C) at atmospheric pressure, comprising the steps when (i) a mixture comprising monochloroacetic acid and dichloroacetic acid is contacted with an extracting agent, (ii) the mixture obtained in step (i) is distilled to produce a stream of monochloroacetic acid and a stream containing dichloroacetic acid and extracting agent, (iii) the stream containing dichloroacetic acid and extracting agent is treated at the regeneration stage, wherein the organic solvent is contacted with a mixture comprising monochloroacetic acid and dichloroacetic acid, in step (i), or wherein the organic solvent is contacted with the mixture in step (i), before and/or during step (ii), or wherein the organic solvent is contacted with a stream comprising dichloroacetic acid and extracting agent, obtained in step (ii) before or during step (iii) or in any combination thereof.

EFFECT: method allows to achieve good separation, moreover, the used extracting agent can be relatively easily regenerated.

17 cl, 8 tbl, 4 ex