Process for refining glycolide and glycolide obtained therefrom
AssigneesChina Petroleum & Chemical Corporation, Shanghai Research Institute of Petrochemical Technology, Sinopec
InventorsWentao Xiong, Rui Wang, Fen Zhou, Jingen Xiong
Life of this patent
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Abstract
A process for refining glycolide includes a step of extracting impurities from a crude glycolide with solvent A, and then a step of recrystallizing with solvent B. Solvent A includes at least two solvents and the solvents are miscible each other. In the process, two types of polar solvents are used for the refining of crude glycolide. The process has a good extraction effect on acidic impurities such as glycolic acid oligomers. The solvents are easily fully removed during the solid-liquid separation and the drying process. Glycolide obtained using this process may have a low free acid content.
Claims10
A process for refining glycolide, comprising the following steps:
- 1) mixing a crude glycolide and solvent A to form a first mixture, filtering the first mixture to obtain a first filter cake and a first filtrate;
- and
- 2) mixing the first filter cake with solvent B to form a second mixture, heating the second mixture, then cooling the heated second mixture to form glycolide crystals, filtering the cooled second mixture to obtain a second filter cake and a second filtrate;
- wherein solvent A is a mixture of solvent I and solvent II, solvent I is selected from polyalcohol ethers having the boiling point at atmospheric pressure of greater than or equal to 180° C., and solvent II is selected from saturated alcohols having the boiling point at atmospheric pressure of less than or equal to 120° C., and
- solvent B is selected from saturated alcohols having the boiling point at atmospheric pressure of less than or equal to 120° C.;
- and solvent B is identical to or different from solvent II.
Dependencies are inferred from the claim text.