System and method for efficiently synthesizing glycolide

A glycolide, high-efficiency technology, applied in chemical instruments and methods, chemical/physical/physical chemical fixed reactors, chemical/physical/physical chemical processes, etc., can solve the problem of high gas phase mass transfer resistance and reaction pressure drop High, low product yield and other issues, to achieve the effect of low mass transfer resistance, reduce production costs, and increase product yield

Pending Publication Date: 2021-06-15
SHANGHAI DONGGENG CHEM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, most of the reactors using glycolic acid to synthesize glycolide are tank reactors with stirring. Because there is a large temperature gradient between the inner layer and the outer layer of the tank reactor, the liquid level in the reactor is relatively high. The mass transfer resistance of the gas phase i

Method used

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  • System and method for efficiently synthesizing glycolide
  • System and method for efficiently synthesizing glycolide
  • System and method for efficiently synthesizing glycolide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0075] In this embodiment, glycolic acid is used as a raw material, and a continuous system for glycolide synthesis is used to produce glycolide, as follows:

[0076] Add 80kg of molten glycolic acid to the gasification chamber of the first set of falling film reaction unit of the system, and add 1wt% of antimony oxide as a dehydration catalyst, open the cooling and heating medium temperature control system of the falling film reactor, and open the circulation pump at the same time to make the material Circular flow. Under the conditions of controlling the reaction temperature to 180° C. and the reaction pressure to 3000 Pa, the reaction was carried out for 3 hours. Water was continuously produced during the reaction. After reacting for 3 hours, glycolic acid was polycondensed and dehydrated to obtain glycolic acid oligomers, and the molecular weight of glycolic acid oligomers was about 2680.

[0077] The glycolic acid oligomer enters the second set of falling film reaction ...

Embodiment 2

[0079] In this embodiment, methyl glycolate is used as a raw material, and a continuous type glycolide synthesis system is used to produce glycolide, as follows:

[0080] Join the 100kg methyl glycolate of melting into the vaporization chamber of the first cover falling film reaction unit, and add dealcoholization catalyst tetraethyl titanate 1.5wt%, open the cold and hot medium temperature control system of falling film reactor, simultaneously Turn on the circulating pump to circulate the material through the whole system. Under the conditions of controlling the reaction temperature to 200° C. and the reaction pressure to 1000 Pa, the reaction was carried out for 5 hours. Methanol was continuously produced during the reaction. After reacting for 5 hours, methyl glycolate was polycondensed and dealcoholized to obtain glycolic acid oligomers, and the molecular weight of glycolic acid oligomers was about 3000.

[0081] The glycolic acid oligomer enters the second set of fallin...

Embodiment 3

[0083] In this embodiment, glycolic acid is used as a raw material, and a system for discontinuous glycolide synthesis is used to produce glycolide, as follows:

[0084] Add glycolic acid to the vaporization chamber of the system at 10kg / h, and add 1wt% of antimony oxide as a dehydration catalyst, open the cooling and heating medium temperature control system of the falling film reactor, and open the circulation pump at the same time, so that the material circulates in the whole system . Control the reaction temperature at 130°C and the reaction pressure at 5000Pa. After 8 hours of reaction, the glycolic acid oligomers are extracted and put into the intermediate storage tank to keep the temperature for use. The gaseous water generated during the reaction is condensed by the condenser and then enters the collection tank. , discharged from the condensate discharge line. Glycolic acid oligomers are obtained by polycondensation and dehydration of glycolic acid, and the molecular ...

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Abstract

The invention discloses a system and a method for efficiently synthesizing glycolide. The system comprises a falling film reaction unit, wherein the falling film reaction unit comprises a falling film reactor, a vaporizing chamber, a circulating pump, a condenser, a collecting tank and a vacuum pump. The method comprises the following steps: adding glycollic acid/glycollate liquid and a catalyst into a gasification chamber through a feeding pipeline, starting a circulating pump, enabling the material to circularly flow, carrying out dehydration/dealcoholization condensation on the glycollic acid/glycollate liquid entering a falling film reactor in the falling film reactor to obtain a glycollic acid oligomer, and further depolymerizing to obtain glycolide gas; enabling the glycolide gas and the unreacted liquid-phase material to enter a vaporizing chamber for gas-liquid separation, enabling the liquid-phase material to enter the falling film reactor again through a circulating pump for the next round of reaction, and enabling the gas to enter a condenser to be condensed and then flow into a collecting tank; and enabling the vacuum pump to adjust the system pressure, so that the reaction is carried out under a negative pressure condition. The system disclosed by the invention is used for synthesizing glycolide and has the advantages of low reaction pressure, accurate temperature control, low gas mass transfer resistance and the like.

Description

technical field [0001] The invention relates to the technical field of organic compound synthesis, in particular to a system and method for efficiently synthesizing glycolide. Background technique [0002] Polyglycolic acid (polyglycolide) is an emerging degradable polymer material, which can be finally degraded by microorganisms or water, and finally produces water and CO 2 . Glycolic acid has good mechanical strength, high barrier properties, and high heat resistance, and has a very broad market space. Polyglycolic acid is an oligomer of glycolic acid obtained by condensation reaction of glycolic acid or glycolic acid ester, and then the intermediate product glycolide, which is then obtained by ring-opening polymerization. The synthesis of polyglycolic acid is mainly limited by the production of the monomer glycolide. Due to the high boiling point of glycolide, glycolic acid oligomers are easy to coke and carbonize under high temperature conditions, resulting in many si...

Claims

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Application Information

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IPC IPC(8): B01J19/24B01J19/00B01J4/00C07D319/12
CPCB01J4/001B01J4/008B01J19/0006B01J19/0013B01J19/002B01J19/0053B01J19/2425B01J2204/002B01J2204/005B01J2204/007B01J2219/00081C07D319/12
Inventor 梁勇军康小玲唐曦郑柏川孙文兵唐圆桦陈真邓任军
Owner SHANGHAI DONGGENG CHEM TECH CO LTD
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