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Method for preparing high-purity m-xylylene diisocyanate

A high-purity technology for iso-xylylene diisocyanate, which is applied in the field of devices for preparing high-purity iso-xylylene diisocyanate, can solve problems such as a large amount of tar and self-polymerization, avoid self-polymerization and improve the precision The effect of distillation yield

Inactive Publication Date: 2021-08-31
甘肃银光聚银化工有限公司
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Problems solved by technology

[0005] The invention relates to a method for preparing high-purity m-xylylene diisocyanate (m-XDI), which relates to the field of rectification of isocyanate, and is used to solve the problem of the existing rectification method in the rectification of products obtained by industrial methods. Defects of large amounts of tar and self-aggregation

Method used

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  • Method for preparing high-purity m-xylylene diisocyanate

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Embodiment 1

[0021] Example 1, such as figure 1 Shown, a kind of method for preparing high-purity m-xylylene diisocyanate is characterized in that: realize by following device:

[0022] The gas phase outlet at the top of the flash evaporator 1 is connected to the first condenser 2 and the second condenser 3 in sequence, the return pipes of the first condenser 2 and the second condenser 3 are connected to the buffer tank 4, and the discharge pipe at the bottom of the buffer tank 4 passes through the suction pump 5 is connected to the circulation storage tank 6, and the light phase outlet of the circulation storage tank 6 is connected to the batch rectification tower 8, and the gas phase outlet at the top of the batch rectification tower 8 is connected to the third condenser 9 and the fourth condenser 10 in turn, and the third condenser 9 and the fourth condenser 10 are connected successively. The condensing pipe of the four condensers 10 is connected to the reflux tank 11, and the discharge...

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Abstract

The invention relates to a method for preparing high-purity m-xylylene diisocyanate (m-XDI). The method is characterized by comprising the following steps: feeding a crude product reaction liquid containing m-xylylene diisocyanate, a solvent and reaction byproducts into a light-phase flash evaporator operated at negative pressure for flash evaporation, and then feeding the above materials into a high-vacuum batch distillation tower for batch distillation, conducting refluxing with different reflux ratios for different fractions so as to finally obtain a qualified product. According to the method, the problem that heavy-phase components of the m-XDI reaction liquid are difficult to separate in a conventional rectification process is solved; and meanwhile, the self-agglutination phenomenon of the m-XDI reaction liquid containing the heavy-phase components in the rectification process is avoided, and the rectification yield of m-XDI can be improved.

Description

technical field [0001] The invention relates to the field of isocyanate purification, in particular to a device and method for preparing high-purity m-xylylene diisocyanate combined with continuous and intermittent rectification. Background technique [0002] m-xylylene diisocyanate (m-XDI) is a colorless or pale yellow liquid with low vapor pressure and high reactivity. It is a polyurethane raw material, and its products have properties such as light stability and yellowing resistance, and are mainly used in the field of high-grade polyurethane ophthalmic lenses. Due to the high boiling point of m-XDI, there are many kinds of by-products formed during the reaction process, and the boiling points of some by-products are relatively similar to those of m-XDI, which makes the rectification and separation process of m-XDI extremely complicated. At present, there are no documents or patents that describe and explain in detail the rectification method for industrial production an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/20C07C265/14B01D3/06B01D3/14
CPCC07C263/20B01D3/06B01D3/14C07C265/14
Inventor 关鹏梁睿渊马瑞进刘耀宗蒙鸿飞杨英朝王婧婧白卫兵
Owner 甘肃银光聚银化工有限公司
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