METHOD OF REMOVING ESTER FROM VAPOROUS MIXTURE Russian patent published in 2017 - IPC B01D53/14 B01D53/96 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of removing the ester (3') from vaporous mixture (5') comprising ester (3'), by contacting the vaporous mixture (5') with an aqueous solution (6') comprising acid (4') appropriate to the ester (3'). Part of the ester (3') is dissolved or otherwise fed into an aqueous solution (6'), the aqueous solution (6') flows into the circulation circuit (73) after the contact. The aqueous solution (6') is subjected to treating in the circulation circuit (73) which comprises: a heating stage (240), a reaction stage (250), wherein the residence time in the reaction stage (250) is from 0.10 to 30 min and the temperature in the reaction stage (250) is from 10 to 95°C, a cooling stage (260). The heating stage (240) precedes the reaction stage (250), the reaction stage (250) precedes the cooling stage (260), the residence time and the temperature in the reaction stage (250) are sufficient to significantly reduce the content of ester (3') in the aqueous solution (6'), wherein the ester (3') is a cyclic diester of an alpha-hydroxycarboxylic acid with I: structural formula, where R is selected from the group consisting of hydrogen and linear or branched aliphatic radicals comprising from 1 to 6 carbon atoms, wherein the acid (4') is an alpha-hydroxycarboxylic acid with II structural formula, appropriate to the diester with I: . structural formula II. Furthermore, the invention relates to an apparatus (2) for implementing the mentioned method. The invention also relates to the use of the apparatus (1) in the method of the present invention during production of a lactide (13') or a polymer polylactic acid (12').

EFFECT: high quality of purification.

14 cl, 7 dwg