Method for refining glycolide and glycolide obtained by method

A technology of glycolide and monohydric alcohol, which is applied to a method of refining glycolide and the field of glycolide obtained therefrom, and can solve the problem of high solvent residue in refining glycolide

Pending Publication Date: 2022-05-13
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The technical problem to be solved by the present invention is the problem that the residual amount of solvent in the refined glycolide obtained by the existing crude glycolide purification method is relatively high, and a refining scheme different from the recrystallization-washing coupling scheme is provided, which has a solvent The technical advantages of easy recycling and low free acid content in the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Polycondensation-depolymerization preparation of crude glycolide: After adding 600g of glycolic acid crystals and 6g of stannous octoate catalyst into the reactor, the temperature was raised from room temperature to 90°C, and after the solid was completely dissolved, the temperature was raised to 120°C to start normal pressure Pre-polymerization, after 2 hours of pre-polymerization, the temperature was raised to 210°C. After the anhydrous evaporated, the system maintained the temperature and started vacuuming. The vacuum degree during this process was controlled at 3kPa. After the anhydrous evaporated, 482g of glycolic acid oligomer was obtained.

[0057] The oligomer is provided to the depolymerization reactor, and the depolymerization system is reacted at a reaction temperature of 290°C, a vacuum degree of 3kPa, and a stirring speed of 100 rpm to prepare crude glycolide, and the reaction is stopped after 2 hours to obtain batches of 1 crude glycolide 397g, acid content...

Embodiment 2

[0059] After mixing 50 g of the crude glycolide obtained in Example 1 with 40 g of n-butanol (water content not higher than 30 ppm) and 10 g of pentylene glycol dimethyl ether, the solid-liquid mixture was stirred at room temperature for 1 h, and then stopped Stir and carry out suction filtration, obtain filter cake 46g after suction filtration. The filter cake was mixed with 92g of n-butanol and heated to 80°C to form a homogeneous solution. Under the condition of rotating speed of 100rpm, cooling to room temperature at a rate of 10°C / h, glycolide is precipitated from the system, and suction filtration is performed, and the above-mentioned cooling recrystallization-filtration operation is repeated for the filter cake once, and the solid obtained by filtration is in Vacuum drying at 30°C for 8 hours gave 37.4 g of white crystals with a total yield of 74.8%. The purity of the refined glycolide measured by DSC is 99.73%, the carboxyl group content in the refined glycolide measu...

Embodiment 3

[0061] After mixing 50 g of the crude glycolide obtained in Example 1 with 40 g of n-butanol (water content not higher than 30 ppm) and 10 g of nonaethylene glycol dimethyl ether, the solid-liquid mixture was stirred at room temperature for 1 h, and then stopped Stir and carry out suction filtration, obtain filter cake 45g after suction filtration. The filter cake was mixed with 94g of n-butanol and heated to 80°C to form a homogeneous solution. Under the condition of rotating speed of 100rpm, cooling to room temperature at a rate of 10°C / h, glycolide is precipitated from the system, and suction filtration is performed, and the above-mentioned cooling recrystallization-filtration operation is repeated for the filter cake once, and the solid obtained by filtration is in Vacuum drying at 30°C for 8 hours gave 36.9 g of white crystals with a total yield of 73.8%. The purity of the refined glycolide measured by DSC is 99.82%. The carboxyl group content in the refined glycolide me...

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Abstract

The invention provides a method for refining glycolide and glycolide obtained by the method. The method comprises the following steps: carrying out impurity extraction on crude glycolide by using a solvent A, and recrystallizing by using a solvent B, wherein the solvent A comprises at least two solvents which are mutually soluble. According to the method disclosed by the invention, two polar solvents are used for refining the crude glycolide, a very good extraction effect is achieved on acidic impurities such as glycolic acid oligomer and the like, and the solvents are easily and fully removed in solid-liquid separation and drying processes, so that the problem of solvent residue in a refined product is solved, and the technical effect of low free acid content of the product is achieved. The technical scheme of the invention has the technical advantages of easy solvent recovery and low free acid content of the product.

Description

technical field [0001] The invention relates to the field of glycolide, in particular to a method for refining glycolide and the glycolide obtained therefrom. Background technique [0002] Polyglycolic acid (PGA) is a synthetic polymer material with good biodegradability and biocompatibility. Unlike traditional polymer materials with stable performance, such as plastics and rubber, PGA is used as a material in After a certain period of time, it will gradually degrade and finally turn into water and carbon dioxide that are harmless to the human body, animals, plants and the natural environment. The application of polyglycolic acid is mainly manifested in two aspects of biomedicine and ecology. [0003] Glycolide is a ring dimer of glycolic acid, that is, a ring-shaped substance formed by the dehydration condensation of two molecules of glycolic acid. The ring-opening polymerization of glycolide is a relatively mature method for preparing polyglycolic acid, which can obtain ...

Claims

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Application Information

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IPC IPC(8): C07D319/12
CPCC07D319/12Y02W30/62B01D11/0288B01D9/0013
Inventor 熊文韬王睿周芬熊金根
Owner CHINA PETROLEUM & CHEM CORP
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