Method for double-solvent lactide recrystallization

A lactide and recrystallization technology, applied in the direction of organic chemistry, etc., can solve the problems of low recrystallization yield and low molecular weight of polylactic acid

Inactive Publication Date: 2008-04-09
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although most reports select ethyl acetate as solvent to obtain lactide can be polymerized to obtain high molecular weight polymer, but the recrystallization yield is not high; It was found that the molecular weight of polylactic acid obtained by polymerization of lactide obtained by recrystallization with ethanol was low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Take 50.0 g of crude lactide, carry out recrystallization and purification according to Table 1, the yield of recrystallization is: 56.8%; the molecular weight of polylactic acid obtained by polymerization is 196,000.

[0013] Table 1

[0014] Recrystallization times

Embodiment 2

[0016] Take 80.0 g of crude lactide, carry out recrystallization and purification according to Table 2, the yield of recrystallization is: 51.0%; the molecular weight of polylactic acid obtained by polymerization is 223,000.

[0017] Table 2

[0018] Recrystallization times

Embodiment 3

[0020] Take 120.0 g of crude lactide, carry out recrystallization and purification according to Table 3, the recrystallization yield is: 40.1%; the molecular weight of polylactic acid obtained by polymerization is 339,000.

[0021] table 3

[0022] Recrystallization times

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PUM

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Abstract

The invention provides a method of using two solvents for recrystallization to get the lactide with the high yield and high purity at the same time. That is also the aim of the invention. The invention is characterized in that the invention uses two solvents successively for recrystallization to get the lactide according to the features that the ethanol is conductive to the improvement of purification yield of lactide, but the molecular weight of the obtained polymer is not high, while the ethyl acetate is conductive to the improvement of the purity of the lactide and can get the polylactic acid with the high molecular weight by polymerization, but the yield is not high. Compared with the public recrystallization methods for the purification of lactide, the invention is characterized by higher yield of recrystallization product and easier obtainment of polylactic acid with high molecular weight by polymerization.

Description

technical field [0001] The invention relates to a method for obtaining high-yield and high-purity lactide through purification by recrystallization. According to the characteristics that ethanol is beneficial to improve the purification yield of lactide, and ethyl acetate is beneficial to improve the purity of lactide and polymerize high-molecular-weight polylactic acid, by controlling the use of different organic solvents in different recrystallization stages to achieve the maximum lactide Good recrystallization effect. Background technique [0002] Today, when sustainable development is advocated, the application of biodegradable polymers is receiving extensive attention. Among the many polyesters studied so far, polylactide (polylactic acid, Polylactic acid, PLA) is one of the important biodegradable materials, which can be used in industry, packaging industry, pharmaceutical industry and other fields. Lactic acid, the initial raw material of polylactide, is widely deri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D319/12
Inventor 刘晓宁魏荣卿刘迎
Owner NANJING UNIV OF TECH
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