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A kind of preparation method of high-purity lactide

A lactide and thermometer technology, applied in the direction of organic chemistry, can solve the problems of low lactide yield, high cost, and low purity, and achieve the effect of less by-products and short reaction time

Active Publication Date: 2020-08-25
SHANDONG GUYUCHUN BIOTECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the current process of preparing lactide by high-temperature cracking of lactic acid oligomers, the yield is low, and the obtained lactide is yellow, the purity is not high, and multiple purifications are required, which makes the yield of lactide low ,high cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] A kind of preparation method of high-purity lactide, comprises steps as follows:

[0033] Weigh 500g of D,L-lactic acid, pour it into a three-necked flask equipped with a thermometer, condensing device and stirrer, heat slowly to boiling, dehydrate under normal pressure, add 10g of zinc oxide when the temperature rises to 130°C (the ratio of lactic acid to its mass is 50) , keep the dehydration under reduced pressure for 8 hours, the pressure is 0.08 ~ 0.09MPa, and condense lactic acid into lactic acid oligomers. After the dehydration is completed, change the condensation receiving device, so that the temperature of the reaction solution is rapidly raised to 250 ° C, and keep the pressure at 2000Pa ~ 0.1MPa , the crude lactide is collected by a three-stage cooling collection system, the product is a yellow solid, and the crude product yield is 95%. The crude product is dissolved in water, cooled, filtered, recrystallized with methanol three times, and vacuum-dried to con...

Embodiment 2

[0035] A kind of preparation method of high-purity lactide, comprises steps as follows:

[0036] Weigh 500g of D,L-lactic acid, pour it into a three-neck flask equipped with a thermometer, condensing device and stirrer, heat slowly to boiling, and dehydrate under normal pressure. ), keep the dehydration under reduced pressure for 10 hours, and the pressure is 0.08-0.09MPa, so that lactic acid can be polycondensed into lactic acid oligomers. MPa, the crude lactide is collected by a three-stage cooling collection system, the product is a yellow solid, and the yield of the crude product is 93%. The crude product is dissolved in water, cooled, filtered, recrystallized three times with absolute ethanol, and vacuum-dried to constant weight. The finished product has a yield of 77%, and the purity of lactide is 99.96% after inspection.

Embodiment 3

[0038] A kind of preparation method of high-purity lactide, comprises steps as follows:

[0039] Weigh 500g of D,L-lactic acid, pour it into a three-neck flask equipped with a thermometer, condensing device and stirrer, heat slowly to boiling, dehydrate under normal pressure, add 5g of antimony trioxide when the temperature rises to 130°C (the ratio of lactic acid to its mass 100), vacuumize, keep the dehydration under reduced pressure for 7 hours, and the pressure is 0.08-0.09MPa, so that lactic acid can be polycondensed into lactic acid oligomers. The crude lactide is 2000Pa~0.1MPa. The crude lactide is collected by a three-stage cooling collection system. The product is a yellow solid, and the yield of the crude product is 95%. The finished product is obtained at constant weight with a yield of 78%, and the purity of lactide is 99.90% after inspection.

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Abstract

The invention provides a preparation method of high-purity lactide. The method comprises the following steps: performing reduced-pressure dehydration to prepare a polylactide (PLA) oligomer, performing high-temperature pyrolysis, performing distillation to obtain crude lactide, and finally performing purification to obtain the polymerization-grade high-purity lactide. According to the method provided by the invention, the reaction conditions required by the reaction are relatively low, the reaction speed is fast, the reaction time is short, and the purified lactide has high purity and can meetthe demand for preparation of high-molecular-weight polylactide obtained through polymerization.

Description

technical field [0001] The invention relates to a method for preparing high-purity lactide, which belongs to the technical field of organic polymers. Background technique [0002] Polylactic acid (PLA) is a fully biodegradable polymer material. Since its raw material, lactic acid, can be fermented from agricultural products, it is considered a sustainable and environmentally friendly compound. Moreover, polylactic acid has good biocompatibility, and the final products of metabolism in the body are carbon dioxide and water, so it has extensive research and application prospects in drug release materials, surgical sutures, tissue engineering scaffold materials and bone repair materials. [0003] There are mainly two methods for PLA synthesis: direct method and indirect method. The direct method uses lactic acid as a raw material to directly prepare PLA. This method is relatively simple, but generally only oligomers can be obtained; the indirect method first uses lactic acid as...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D319/12
CPCC07D319/12
Inventor 袁文博赵春华李建苏红清褚吉阳
Owner SHANDONG GUYUCHUN BIOTECHNOLOGY CO LTD