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Catalyst for preparing lactides from lactic acid and method for preparing lactides from lactic acid

A lactide and catalyst technology, applied in catalyst activation/preparation, chemical instruments and methods, physical/chemical process catalysts, etc., can solve the problems of affecting product yield, reaction temperature, etc. The effect of increasing the chance of contact

Active Publication Date: 2019-06-18
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In order to solve the problem of high reaction temperature in the process of preparing lactide from lactic acid in the prior art, which affects the product yield, the invention provides a catalyst for the reaction of preparing lactide from lactic acid. The catalyst is supported by graphene Composite oxides of Zn and Ti, through graphene and ZnO and TiO 2 The interaction between these materials is beneficial to promote the dehydration balance of the polycondensation reaction, obtain lactic acid oligomers with moderate molecular weight, reduce the temperature of the depolymerization reaction, improve the yield and quality of lactide products, and achieve efficient, simple and environmentally friendly preparation of lactide. Lactide

Method used

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  • Catalyst for preparing lactides from lactic acid and method for preparing lactides from lactic acid
  • Catalyst for preparing lactides from lactic acid and method for preparing lactides from lactic acid
  • Catalyst for preparing lactides from lactic acid and method for preparing lactides from lactic acid

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Experimental program
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Effect test

Embodiment 1

[0044] Catalyst preparation:

[0045] a. Preparation of ZnO-TiO 2 Composite oxide: Weigh 17.0g of butyl titanate, add it into 40mL of absolute ethanol under strong stirring, then add 16mL of glacial acetic acid into it, after stirring evenly, slowly drop into it 7.2mL of water, 20mL ethanol, 14.85g Zn(NO 3 ) 2 •6H 2 A solution composed of O zinc nitrate, and keep stirring until a uniform and transparent sol is formed. After standing for 24 hours, after aging the gel, dry it at 100°C for 10 hours to obtain a dry gel, and then bake it at 500°C for 4 hours to obtain ZnO- TiO 2 composite oxides.

[0046] b. Graphene oxide supported ZnO-TiO 2 Composite oxide: ultrasonically disperse 0.1g of graphene oxide into 20mL ethanol solution, then add 9.9g of ZnO-TiO 2 After the composite oxide is evenly stirred, it is transferred to a closed reaction kettle, subjected to hydrothermal treatment at 150-250°C for 6-8 hours, cooled, filtered, washed, and vacuum-dried at 65°C for 12 hours...

Embodiment 2

[0048] Preparation of lactide:

[0049] (1) Lactic acid free water: take 600g L-lactic acid (the lactic acid content is about 88.0%), put it into a four-necked flask with a stirring system, use a vacuum circulating pump to maintain the system pressure at 50kpa, and start the process under vacuum. Heating, gradually heating to 110°C~120°C, dehydration for 2 hours, at this time, the free water in the reaction system is slowly distilled out of the reaction system.

[0050] (2) Lactic acid polycondensation reaction to generate lactic acid oligomers: After the free water in the system is almost completely removed, add 3.0 g of the catalyst prepared in Example 1 to the system, and increase the vacuum degree of the system to reduce the pressure of the system to Slowly drop to about 10.0kPa, the temperature of the feed liquid gradually rises to 140~150℃, and react for 3 hours. At this time, the polycondensation reaction occurs between the lactic acid molecules, and the water generated...

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Abstract

The invention provides a catalyst for preparing lactides from lactic acid and a method for preparing lactides from lactic acid. The catalyst uses butyl titanate and zinc nitrate as raw materials; a sol-gel method is used for preparation to obtain a ZnO-TiO2 composite oxide; then, the ZnO-TiO2 composite oxide is loaded to graphene oxide; hydrothermal sealed treatment is performed to obtain a catalyst. After lactic acid dewatering, the catalyst is used for catalysis; depolymerization is performed at 5.0 to 15.0 kPa and 140 to 150 DEG C; depolymerization is performed at 500 to 100 Pa and 160 to 200 DEG C; coarse lactides are obtained; after purification, lactides are obtained. In the catalyst, the dispersion degree of ZnO and TiO2 particles is increased by graphene; the catalysis capability of active ingredients is improved. Particles with different valence states achieve mutual action in crystal lattices; the speed of the lactic acid polycondensation reaction and the oligomer depolymerization reaction is accelerated; meanwhile, the temperature required in the reaction process is lowered. The prepared lactides have high purity and high yield.

Description

technical field [0001] The invention relates to the preparation of a bio-based material polylactic acid intermediate lactide, in particular to its catalyst, its preparation method and a method for preparing high-quality and high-yield lactide using the catalyst. Background technique [0002] Polylactic acid, as a green polymer material with broad application prospects, has good mechanical strength, biocompatibility, biodegradability and bioabsorbability, and is widely used in medical treatment, agriculture, food packaging, daily necessities, etc. field. And with the continuous maturity of polylactic acid production technology and the continuous development of the application market of polylactic acid, the production of polylactic acid from non-food crops → lactic acid → polylactic acid has begun to enter the period of industrialization development. The preparation method of polylactic acid mainly consists of one-step method and two-step method. They all use lactic acid, lac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/06B01J37/03B01J37/10C07D319/12
Inventor 孙启梅王崇辉王领民樊亚超王鹏翔姚新武
Owner CHINA PETROLEUM & CHEM CORP
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