Lactide combined purification method

A purification method and lactide technology, applied in the direction of organic chemistry, can solve the problems of long crystallization period of solvents, not suitable for large-scale production, pollution of the environment, etc., and achieve the effect of shortening the purification period

Active Publication Date: 2012-12-12
武汉三江航天固德生物科技有限公司
View PDF5 Cites 6 Cited by
  • 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 a coupling purification method of lactide, which can solve the problems of long cycle of solvent crystallization, environmental pollution, and unsuitability for large-scale production

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach

[0017] Overall implementation of the present invention is as follows:

[0018] 1. A coupling purification method of lactide, mainly comprising the following steps:

[0019] 1) weighing, taking lactide, its purity is 85%~94%;

[0020] 2) Rectification, the rectification pressure is controlled at 1kPa~10kPa, and the rectification temperature is controlled at 130°C~165°C;

[0021] 3) Collect 1, collect fractions, and control the temperature of fractions at 118°C to 122°C;

[0022] 4) Crystallization, carry out non-solvent crystallization, feed at 95°C~105°C, control the crystallization temperature at 97°C~97.5°C, and control the crystallization time at 50min~70min;

[0023] 5) Collect 2, the collection purity is 99.5% lactide.

[0024] The lactide is a left-handed lactide.

[0025] The rectification pressure range is preferably 3kPa~8kPa.

[0026] The rectification temperature is preferably 140°C to 150°C.

Embodiment 1

[0028] 1) Weighing, taking by weighing 200Kg of left-rotating lactide with a purity of 94%;

[0029] 2) Rectification, the rectification pressure is controlled at 1kPa, and the rectification temperature is controlled at 130°C;

[0030] 3) Collect, collect fractions, and control the temperature of fractions at 118°C~122°C;

[0031] 4) Crystallization, feed at 95°C, control the crystallization temperature at 97°C~97.5°C, and control the crystallization time at 50min;

[0032] 5) For the finished product, 99.5% pure lactide is collected to obtain 90Kg, and the remaining low-purity lactide enters the rectification process for recycling.

Embodiment 2

[0034] 1) Weighing, weighing 200Kg of left-rotating lactide with a purity of 94%;

[0035] 2) Rectification, the rectification pressure is controlled at 10kPa, and the rectification temperature is controlled at 165°C;

[0036] 3) Collect, collect fractions, and control the temperature of fractions at 120°C~122°C;

[0037] 4) Crystallization, feed at 105°C, control the crystallization temperature at 97°C~97.3°C, and control the crystallization time at 70min;

[0038] 5) For the finished product, 99.5% pure lactide is collected to obtain 92Kg, and the remaining low-purity lactide enters the rectification process for recycling.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
purityaaaaaaaaaa
Login to view more

Abstract

The invention discloses a lactide combined purification method and belongs to the field of lactic acid manufacture. The lactide combined purification method comprises the following steps of weighing low-purity lactide, carrying out rectification, collecting fractions, carrying out non-solvent crystallization, and collecting lactide having purity of 99.5%. The lactide combined purification method adopts a high-vacuum rectification and non-solvent crystallization combined technology, solves the problem that only a high-vacuum rectification technology further improves lactide purity difficultly, and further realizes purification effects by a non-solvent crystallization process. Through the lactide combined purification method, lactide purity reaches to above 99.5%. The rest of low-purity lactide can be distilled sequentially. The lactide combined purification method shortens a purification period, avoids use of a large amount of a solvent and is suitable for large-scale production.

Description

technical field [0001] The invention belongs to the field of lactic acid production, and in particular relates to a lactide coupling purification method. Background technique [0002] Lactide is an important compound that can be used to prepare polylactic acid and its copolymers, and its purity has a direct impact on whether polylactic acid with high relative molecular weight can be synthesized. When the lactide purity index does not meet the specified requirements, only polylactic acid with a relatively low molecular weight can be obtained, which has no application value. Therefore, lactide purification method has been considered as a key technology of polylactic acid synthesis technology. [0003] The purification methods of lactide are generally divided into three types: recrystallization method, gas-assisted evaporation method and hydrolysis method. Recrystallization is currently the most commonly used lactide purification method. Patent documents with application num...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): C07D319/12
Inventor 谢剑宏刘俊飞赵文胜徐仁义梁庭德
Owner 武汉三江航天固德生物科技有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap