Preparation method and preparation device of crude lactide and prepared crude lactide

A preparation device and lactide technology, applied in separation methods, chemical instruments and methods, steam condensation, etc., can solve the problems of high energy consumption, low yield of crude lactide, high acid and moisture content, etc., and achieve energy reduction consumption effect

Pending Publication Date: 2021-08-10
北京朗净汇明生物科技有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide an efficient method and device for preparing crude lactide by depolymerization of lactic acid oligomers, which is suitable for industrial production, and solve the problem of crude lactide yield in the depolymerization process of lactic acid oligomers. The problem of low energy consumption and high energy consumption reduces the production cost, and at the same time solves the problem of high oligomer, acid and moisture content in crude lactide, and reduces the burden of crude lactide purification

Method used

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  • Preparation method and preparation device of crude lactide and prepared crude lactide
  • Preparation method and preparation device of crude lactide and prepared crude lactide
  • Preparation method and preparation device of crude lactide and prepared crude lactide

Examples

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Embodiment 1

[0045] Turn on the vacuum unit 7 to keep the vacuum degree of the depolymerization system at 1000Pa, slowly adjust the flow regulating valve 2 to allow the depolymerization mother liquor to flow into the depolymerization reactor 3, adjust the temperature of the depolymerization reactor 3 to 210°C, and lactide begins to form The steam overflows, and the liquid content of the depolymerization reactor 3 is kept at 60% through the flow regulating valve 2, and the overflowing lactide steam is removed by the tower type gas-liquid separator 4 with 6 layers of trays at 120°C. The entrained lactic acid oligomers and heavy components pass through the first-stage double-flow heat exchanger 5 at 98°C to collect the main crude lactide, and further collect a small amount of crude lactide through the second-stage double-flow heat exchanger 6 at 90°C. crude lactide. As the depolymerization reaction proceeds, the viscosity of the mother liquor in the depolymerization reactor 3 increases gradua...

Embodiment 2-5

[0048] Using the same method steps as in Example 1, only the technical parameters are changed, as shown in Table 1.

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Abstract

The invention relates to a preparation method and a preparation device of crude lactide and the prepared crude lactide, and the preparation method comprises the following steps: (1) under the condition of negative pressure, feeding lactic acid oligomer into a depolymerization reaction kettle; (2) depolymerizing the lactic acid oligomer in a depolymerization reaction kettle by stirring to generate lactide gas; and (3) under the condition of negative pressure, moving the lactide gas out of the depolymerization reaction kettle, and obtaining crude lactide after gas-liquid separation and heat exchange. A traditional conveying pump unit is abandoned, vacuum of a depolymerization system is used for conveying materials, and energy consumption is reduced. The depolymerization reaction kettle is combined with the tower type separator and the multi-stage heat exchanger for condensation and collection, so that the quality of crude lactide is improved; the utilization rate of the depolymerization mother liquor is increased by blowing air from the bottom of the depolymerization reaction kettle, so that the yield of crude lactide is increased.

Description

technical field [0001] The invention relates to a method and device for preparing crude lactide and the prepared crude lactide, belonging to the field of bio-based new materials. Background technique [0002] Polylactic acid is an important new biodegradable polymer material, which has great application prospects in the fields of plastics, textiles, and medicine. With the promotion and implementation of the domestic "plastic ban", the country has higher and higher requirements for environmental protection, and the polylactic acid market has shown explosive growth. The development of polylactic acid technology has great market demand and industrial value. The core technology of polylactic acid mainly includes: (1) lactic acid prepolymerization-depolymerization; (2) lactide refining and purification; (3) lactide ring-opening polymerization. The yield of lactic acid prepolymerization-depolymerization stage determines the total yield of polylactic acid, and the quality of crude...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D319/12B01D49/00B01D5/00
CPCB01D5/0003B01D5/0036B01D49/00C07D319/12
Inventor 陈清文马博谋劳含章盛浩强林园园
Owner 北京朗净汇明生物科技有限公司
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