The purification of raw lactide from residual oligomers, lactic acid and water was carried out by recrystallization from ethanol, isopropanol, ethyl acetate and butyl acetate. The process was carried out in a 100 mL beaker on a heating plate equipped with a magnetic stirrer. The ratio of raw lactide:solvent in the case of alcohols and ethyl acetate was taken in the mass ratio of 2:1, and in case of butyl acetate—3:1. The temperature of 70 °C and stirring were maintained by a heating plate, IKA C-MAG HS-7 (IKA-Werke GmbH & Co., KG, Staufen, Germany). After complete dissolution of the substance, the beaker was removed from the hotplate and cooled to 5 °C. Then, lactide crystals were separated from the solvent by using Buchner funnel vacuum filtration.
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