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Method and device for producing lactide

A lactide and reaction vessel technology, applied in the field of lactide manufacturing, can solve problems such as the difficulty of separating lactide coloring substances

Active Publication Date: 2022-02-08
荷兰普拉克公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Furthermore, it has additionally been shown that the separation of lactide coloring substances from crude lactide is difficult in practice

Method used

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  • Method and device for producing lactide
  • Method and device for producing lactide
  • Method and device for producing lactide

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Embodiment Construction

[0033] The method according to the present invention for producing lactide by figure 1 Ester apparatus shown in cross-propanamide explained. More specifically, the figure shows lactide reactor 1 via line 2 to a degree of polymerization of about 6-50 lactic acid oligomer feed to the lactide reactor 1. Through a closed loop depolymerization crude lactide oligomers made from these esters, in one embodiment, at a suitable temperature and pressure of the process is catalyzed by stannous octoate, e.g., as are known in the prior art. The crude lactide stream from the lactide reactor 1 drawn out direct esterification reaction vessel 4 via line 3. In this embodiment, the reaction vessel 4 consists of three continuous stirred tank reactor 5 composition. The main stream from lactide (more than 80wt%, preferably more than 90wt%, more preferably more than 95wt%) and a small amount of lactic acid, lactylates, water, lactic acid oligomers and possibly other impurities.

[0034] Esters derived fr...

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Abstract

The present invention relates to a method and an apparatus for producing lactide, wherein crude lactide prepared by depolymerization of lactic acid oligomers is purified by a distillation step. According to the invention, the crude lactide produced is kept in the reaction vessel at a temperature of 97° C. to 200° C. for a period of at least 5 hours before the distillation step. Retaining the lactide in the reaction vessel for a period of time results in a decrease in the lactide content and an increase in the concentration of lactic acid oligomers, enabling a more efficient purification of the crude lactide produced during the subsequent distillation. A pre-distillation step gives additional advantages.

Description

Technical field [0001] The present invention relates to a process for producing lactide, wherein the solution prepared by the polymerization of lactic acid oligomers by distilling the crude lactide purification step. The present invention further relates to an apparatus for producing lactide, which comprises a solution of poly lactic acid oligomers of lactide to lactide reactor for pipelined lactide withdrawn from the reactor to the distillation tower. Background technique [0002] Hydroxycarboxylic acid lactide dimeric cyclic ester of (1,4-dimethyl-3,6-dioxane-2,5-dione) is sometimes referred dilactide (dilactide), capable of for producing a high molecular weight polylactic acid (PLA) or PLA-based copolymer used as a precursor or intermediate compound. Considering the ability of these polymers and biologically degradable by hydrolysis of simultaneously forming physiologically and environmentally acceptable degradation products, these polymers can be used in biomedical and other ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D319/12
CPCC07D319/12B01D3/34B01D3/42B01J19/0013B01J19/0066B01J2219/00033B01J2219/00051B01J2219/00166
Inventor J·J·德弗里斯A·I·卡瓦科莫拉奥A·B·德汉恩
Owner 荷兰普拉克公司