Sulzer Chemtech Ag

Sulzer Management Ag

Daniel Dünnenberger

François Loviat

A method for the removal of an ester (') from a vapor mixture (&#x2032;) containing the ester (&#x2032;) is disclosed. The method comprises the steps of by bringing the vapor () mixture (&#x2032;) into contact with an aqueous solution (&#x2032;) containing the acid (&#x2032;) corresponding to the ester (&#x2032;), wherein a portion of the ester (&#x2032;) is dissolved in or otherwise transferred to the aqueous solution (&#x2032;), and the aqueous solution (&#x2032;) is after the contact led in a circulation (), the aqueous solution (&#x2032;) is processed in the circulation () in a process comprising: a heating step (), a () reaction step () having a residence time and a temperature, a cooling step (), wherein the heating step () precedes the reaction step (), the reaction step () precedes the cooling step (), and the residence time and the temperature in the reaction step () are sufficient to substantially reduce the content of the ester (&#x2032;) in the aqueous solution (&#x2032;). The invention further () relates to an apparatus () for carrying out said process. The present invention further relates also to the use of the apparatus () in the method of the invention, preferably in the production of a lactide (&#x2032;) or a polylactic acid polymer (&#x2032;).

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Winterthur, Switzerland

Daniel Dünnenberger