A METHOD FOR LACTIDE SYNTHESIS FROM LACTIC ACID

摘要

PURPOSE: A method for preparing lactide from lactic acid is provided to obtain high purity lactide with high yield, thereby lowering cost for producing polylactic acid. CONSTITUTION: A method for preparing lactide comprises the steps of: performing catalytic reaction of a lactic acid solution with water under the presence of a first organic solvent; performing phase separation of the product and forming a mixture of a second organic solvent and water; and extracting and evaporating the isolated organic part to obtain lactide. The lactic acid solution contains 10-98 % lactic acid. [Reference numerals] (AA) Lactic acid solution; (BB) Mixing lactic acid solution with xylene; (CC) Catalyst reacting with the mixture of lactic acid solution and xylene (reaction temperature: around 130°C); (DD) Mixing the reactant of the previous step, ethyl acetate and water; (EE) Separating organic phase part after extracting reaction and evaporating; (FF) Collecting solid phased lactide