Continuous production method of high-content high-optical-purity lactate

A technology of optical purity and lactic acid ester, which is applied in the direction of preparation of ester group and hydroxyl reaction

Inactive Publication Date: 2012-09-19
XIAOGAN ESUN NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] None of the published patents use lactide and absolute alcohol as raw materials to produce lactide with high optical purity through transesterification, nor do they use lactide purified mother liquor and absolute ethanol as raw materials to produce electronic-grade ethyl lactate ester

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The raw material is purchased L-lactic acid with a mass content of 88%. A falling film evaporator is used to carry out vacuum distillation of the raw material lactic acid. The material temperature in the falling film evaporator is maintained at 50°C and the vacuum degree is maintained at 8000Pa. The concentrated lactic acid Wherein the monomer content is above 99%. Transfer 500Kg of concentrated lactic acid into the polycondensation tank through a delivery pump, add zinc lactate as a catalyst at a weight ratio of zinc lactate to lactic acid of 5 / 10000, and raise the material from 80°C to 120°C within 2 hours. The vacuum degree is maintained at 5000Pa, and the whole reaction is carried out with stirring. The viscosity of the lactic acid oligomer is detected by an online viscometer. According to the relationship between viscosity and molecular weight, determine whether its molecular weight is between 1000 and 2500. Inside, the oligomeric lactic acid is transported into th...

Embodiment 2

[0033] 5000Kg of concentrated D-lactic acid is transported into the polycondensation tank through a delivery pump, and zinc oxide is added as a catalyst according to the weight ratio of zinc oxide and lactic acid as 10 / 10000, and the material is raised from 80 °C to 120 °C within 2 hours. ℃, the vacuum degree is maintained at 4000Pa, and the whole reaction is carried out with stirring. The viscosity of the lactic acid oligomer is detected by an online viscometer. According to the relationship between viscosity and molecular weight, its molecular weight is determined to be 1600. The oligomeric lactic acid is transported into the depolymerization kettle by vacuum pressure difference, and zinc oxide is added as a catalyst according to the weight ratio of zinc oxide and lactic acid as 10 / 10000. The whole reaction is carried out with stirring, and the temperature of the material is rapidly raised to 185°C , the vacuum degree is maintained at 1500Pa. After the lactide vapor obtained ...

Embodiment 3

[0035] Add the lactide recovery mother liquor and absolute ethanol into the dissolution tank at a weight ratio of 1:1.6, mix well, run the delivery pump, and pass the mixed solution through the SO2 tank at a flow rate of 600L / h. 4 2- / TI 2 o 4 The fixed-bed reactor with solid high-strength acid catalyst carries out transesterification reaction, the mother liquor after the reaction enters the buffer tank, and then the mother liquor is continuously input into the rectification tower at a flow rate of 600L / h through the delivery pump, and the temperature of the material at the bottom of the primary rectification tower is controlled at 140℃~141℃, the temperature at the top of the tower is 70~75.5℃, the vacuum degree in the tower is -0.04MPa, the ethanol is continuously recovered from the top of the tower, and the bottom product enters the secondary rectification tower, and the temperature of the material at the bottom of the secondary rectification tower is controlled The temper...

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Abstract

The invention relates to a continuous production method of high-content high-optical-purity lactate. The continuous production method of high-content high-optical-purity lactate includes the steps of adding catalyst in lactic acid to allow for polycondensation to obtain lactic acid oligomer with 1000-2500 molecular weight; adding catalyst into the lactic acid oligomer to allow for depolymerization to obtain crude lactide; and refining the crude lactide, and subjecting the refined lactide and organic alcohol to full-reflux reaction to obtain lactate. The continuous production method is simple in process, easy and simple to operate and suitable for industrial production and application. The materials can all be utilized. No 'three wastes' emission occurs. Content of the synthetized lactate is more than 99.5%, and optical purity of the lactate can reach more than 99%.

Description

technical field [0001] The invention belongs to the technical field of organic chemical industry, and specifically relates to a method for directly and continuously producing lactate with high content and high optical purity through transesterification reaction using refined grade lactide and anhydrous alcohol as raw materials. Background technique [0002] Lactate has a special rum, fruit and cream aroma, and is an important fine chemical raw material. Because lactate contains asymmetric carbon atoms, it has two optical isomers and is also an important industrial solvent with optical activity. It can be used as nitrocellulose, cellulose acetate, alkyd resin, kauri ester, Manila resin, Solvent for rosin, shellac, vinyl resin, paint, etc., and high-grade solvent for artificial pearls. It is also used as a plasticizer in other industrial fields, used in asymmetric synthesis to synthesize optically active carboxylic acid esters, used in pharmaceuticals as a lubricant for press...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/68C07C67/03
Inventor 杨义浒徐杰
Owner XIAOGAN ESUN NEW MATERIAL
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