Preparation method of lactide

A technology of lactide and lactic acid, which is applied in the direction of organic chemistry, can solve the problems of low molecular weight of polymerization products, high polymerization reaction temperature, and poor mechanical properties of products, so as to reduce production costs, reduce cracking temperature, and improve production efficiency. Effect

Pending Publication Date: 2022-04-12
普立思生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is simple, but the molecular weight of the polymer product obtained by this method is low and the molecular weight distribution is wide
In addition, the polymerization temperature is high, the color of the product is darker, and the mechanical properties of the product are poor

Method used

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  • Preparation method of lactide
  • Preparation method of lactide
  • Preparation method of lactide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] 1.1 Heat 180g of lactic acid, 40g of PEG400, 1.34g of dimethylolpropionic acid and 0.5g of stannous chloride into a round-bottomed flask in sequence, rapidly raise the temperature of the flask to 150°C and stir the reactants while collecting the reaction Generated water, when no liquid distilled out from the reaction, was vacuumized for polycondensation reaction. After 10 hours, the oligomerization reaction was completed to obtain 140 g of oligomeric lactic acid, and the molecular weight of oligomeric lactic acid was 3800 g / mol as measured by sampling.

[0035] 1.2 Mix the oligomeric lactic acid and 1 g of antimony trioxide in Example 1.1 and heat them to 190 degrees, vacuumize and carry out the cracking reaction. During the cracking reaction, continuously fill in nitrogen gas. When the cracking product no longer distills out, it is regarded as The reaction was completed, the reaction time was 1.5 h, and the yield was 96%. The lactide obtained in the present embodiment ...

Embodiment 2

[0039] 2.1 Heat 180g of lactic acid, 80g of PEG400, 5.28g of glyceric acid and 0.6g of stannous benzoate into the round-bottomed flask in turn, rapidly raise the temperature of the flask to 160 degrees Celsius and stir the reactants, while collecting the water generated by the reaction , when the reaction no longer has liquid distilling out, vacuumize the polycondensation reaction, after 8 hours, the oligomerization reaction ends, and the molecular weight of oligomeric lactic acid measured by sampling is 4100g / mol.

[0040] 2.2 Mix and heat the oligomeric lactic acid and 0.5g stannous benzoate in Example 2.1 to 180 degrees, vacuumize and carry out the cracking reaction, constantly charge nitrogen gas during the cracking reaction, when the cracking product no longer distills out, depending on To complete the reaction, the reaction time was 2h, and the yield was 95%. The purity of lactide measured by sampling was 97.2%, and the acid value was 22ppm.

Embodiment 3

[0042] 3.1 Heat 180g of lactic acid, 60g of PEG600, 4.02g of dimethylolpropionic acid and 0.9g of stannous octoate into a round-bottomed flask in turn, rapidly raise the temperature of the flask to 140 degrees Celsius and stir the reactants, and collect the reaction products at the same time Water, when the reaction no longer has liquid to distill, vacuumize and carry out the polycondensation reaction, after 12 hours, the oligomerization reaction ends, and the molecular weight of the oligomeric lactic acid measured by sampling is 3500g / mol.

[0043] 3.2 Mix and heat the oligomeric lactic acid and 0.5 g of stannous octoate in Example 3.1 to 190 degrees, vacuumize and carry out the cracking reaction, and constantly fill in nitrogen gas during the cracking reaction, and when the cracking product no longer distills out, depending on To complete the reaction, the reaction time is 1.5 h, and the yield is 96.5%. The purity of lactide measured by sampling was 97.3%, and the acid value...

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Abstract

The invention discloses a lactide preparation method which comprises the following steps: performing dehydration oligomerization on a lactic acid monomer, a polyethylene glycol polymer and polycarboxylic acid under the action of a catalyst to obtain hyperbranched oligomeric lactic acid, and then cracking to generate lactide. According to the process disclosed by the invention, the polyethylene glycol polymer and the polycarboxylic acid are added during lactic acid oligomerization to synthesize hyperbranched oligomeric lactic acid with a random structure, the number of terminal groups is increased, the cracking speed of the oligomeric lactic acid is increased, and meanwhile, due to the addition of the polyethylene glycol polymer, the viscosity of the oligomeric lactic acid can be reduced when the viscosity is relatively high in the later stage of dehydration; and the melting point of the polylactic acid with the random structure is low, so that the cracking temperature of the polylactic acid is reduced, the carbonization rate of the polylactic acid is reduced, the contact area of the polylactic acid can be increased, and the mass transfer and heat transfer efficiency of the polylactic acid is improved.

Description

technical field [0001] The invention relates to the field of lactide synthesis, in particular to a method for preparing lactide. Background technique [0002] Polylactic acid is a green polymer material with good biocompatibility and biodegradability. At the same time, its mechanical properties, impermeability, gloss, light transmittance and processing properties are also similar to polystyrene. Various disposable products are prepared by injection molding, blister molding and melt spinning to replace the existing non-degradable plastics. The synthesis methods of polylactic acid mainly include direct polycondensation method and ring-opening polymerization method. The direct polycondensation method is to directly polycondense lactic acid into PLA under the action of a catalyst. This method is simple, but the molecular weight of the polymer product obtained by this method is low and the molecular weight distribution is wide. In addition, the polymerization temperature is hi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D319/12C08G63/664
Inventor 边新超余莉花吴颖
Owner 普立思生物科技有限公司
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