Preparation method of high-light pure lactide

A lactide, high-light technology, applied in organic chemistry and other directions, can solve the problems of yield, light purity affecting the cost and performance of polylactic acid, catalyst affecting the application range, limiting the application in high-end fields, etc., to improve the effective conversion utilization rate, The effect of easy purification and reduction of the degree of racemization

Inactive Publication Date: 2018-10-19
SHANDONG SHOUGUANG JUNENG GOLDEN CORN CO LTD +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the industrial production of polylactic acid adopts a two-step method: lactic acid-lactide-polylactic acid. With the expansion of the application field of polylactic acid, lactide as an intermediate for the preparation of polylactic acid has also attracted much attention, and its yield Light purity seriously affects the cost and performance of preparing polylactic acid; the use of its catalyst seriously affects its application range
At present, lactide produced industrially is mainly prepared by using tin-based substances as catalysts, such as stannous octoate. Such catalysts have certain toxicity and cannot be used in fields with high safety requirements such as medical fields, which limits their use in high-end fields. application

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] 1. Add 50g of L-lactic acid to the reaction kettle, then add 0.25g of 1,3-dimethyl-2-imidazolidinone, and polycondense for 2 hours at 150°C and vacuum degree of -0.08Mpa to prepare lactic acid low Polymer.

[0013] 2. Lactic acid oligomers were depolymerized at 200° C. and a vacuum of -0.09 MPa to obtain crude lactide.

[0014] 3. Use 150g of pure water to mix and wash the crude lactide for 10 minutes. Under the suction of the vacuum pump, the water is removed through the suction chamber at the bottom of the kettle. Repeat the same process above once, and then put the water-ester mixture into the negative The dehydration device is used for negative pressure dehydration.

[0015] 4. Under the conditions of an absolute pressure of 200 Pa and 180°C, the sample obtained in step 3 was subjected to low-pressure rectification to obtain high-gloss pure lactide.

[0016] The total yield of purified lactide obtained in this example is 86%, the melting point is 96.5° C., and the...

Embodiment 2

[0018] 1. Add 100g of L-lactic acid to the reaction kettle, then add 0.6g of 1,3-dimethyl-2-imidazolidinone, and polycondense for 2.5h at 100°C and vacuum degree of -0.09Mpa to prepare lactic acid Oligomer.

[0019] 2. Add 0.11 g of sulfonylureas to the lactic acid oligomer, depolymerize the lactic acid oligomer at 250° C. and a vacuum of -0.095 MPa to obtain crude lactide.

[0020] 3. Use 150g of pure water to mix and wash the crude lactide for 10 minutes. Under the suction of the vacuum pump, the water is removed through the suction chamber at the bottom of the kettle. Repeat the same process above once, and then put the water-ester mixture into the negative The dehydration device is used for negative pressure dehydration.

[0021] 4. Under the conditions of an absolute pressure of 200 Pa and 180°C, the sample obtained in step 3 was subjected to low-pressure rectification to obtain high-gloss pure lactide.

[0022] The total yield of purified lactide obtained in this examp...

Embodiment 3

[0024] 1. Add 150g of L-lactic acid to the reaction kettle, then add 0.75g of 1,3-dimethyl-2-imidazolidinone, and polycondense for 3 hours at 200°C and vacuum degree of -0.07Mpa to prepare lactic acid low Polymer.

[0025] 2. Add 0.15 g of sulfonylureas to the lactic acid oligomer, depolymerize the lactic acid oligomer at 300° C. and a vacuum of -0.09 MPa to obtain crude lactide.

[0026] 3. Use 150g of pure water to mix and wash the crude lactide for 10 minutes. Under the suction of the vacuum pump, the water is removed through the suction chamber at the bottom of the kettle. Repeat the same process above once, and then put the water-ester mixture into the negative The dehydration device is used for negative pressure dehydration.

[0027] 4. Under the conditions of an absolute pressure of 200 Pa and 180°C, the sample obtained in step 3 was subjected to low-pressure rectification to obtain high-gloss pure lactide.

[0028] The total yield of purified lactide obtained in this...

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Abstract

The invention belongs to the technical field of organic matter preparation, and relates to a preparation method of high-light pure lactide. The high-light pure lactide is prepared by a one-stage or two-stage catalytic reaction, and the method comprises the following specific steps: with L-lactic acid as a raw material, adding 1,3-dimethyl-2-imidazolinone as a catalyst to prepare a lactic acid oligomer; and then directly adding sulfonylurea as a depolymerization catalyst, depolymerizing under high temperature and vacuum conditions, preparing crude lactide, and purifying the crude lactide to obtain high-light pure lactide. The total yield of lactide of the method reaches 86% or more, the melting point is 96.5 DEG C or more, and the optical purity of an isomer is 99.5% or more.

Description

technical field [0001] The invention belongs to the technical field of organic matter preparation, and in particular relates to a preparation method of high-gloss pure lactide. technical background [0002] The severe plastic waste pollution caused by non-degradable disposable petroleum-based products has become an important source of ecological environmental pollution in my country and the world. The development of new environmentally friendly materials and the fundamental solution to the problem of plastic pollution have become a research hotspot for many researchers. As a thermoplastic aliphatic polyester derived from plants, lactic acid has similar physical and mechanical properties to polypropylene and is completely biodegradable. It is widely used in the fields of electronics, disposable products, automobiles, and biomedicine. At present, the industrial production of polylactic acid adopts a two-step process: lactic acid-lactide-polylactic acid. With the expansion of th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D319/12
CPCC07D319/12
Inventor 高世军吴泽华侯月会李辰张晨海
Owner SHANDONG SHOUGUANG JUNENG GOLDEN CORN CO LTD
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