Preparation method of methylene diphenyl diisocyanate

A technology of xylylene diisocyanate and m-xylylenediamine hydrochloride, applied in the field of isocyanates, can solve the problems of long reaction time, high impurity content, low product yield, etc., and achieves improved purity and higher reaction yield. rate, increase conversion rate

Active Publication Date: 2017-05-31
SHANDONG EFIRM BIOCHEMISTRY & ENVIRONMENTAL PROTECTION CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But above-mentioned method exists reaction time is long, and the productive rate of product is lower, and impurity content height

Method used

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  • Preparation method of methylene diphenyl diisocyanate
  • Preparation method of methylene diphenyl diisocyanate
  • Preparation method of methylene diphenyl diisocyanate

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preparation example Construction

[0026] The embodiment of the present invention discloses a preparation method of xylylene diisocyanate, comprising the following steps:

[0027] A), performing a salt-forming reaction with m-xylylenediamine and hydrogen chloride in an inert organic solvent to obtain m-xylylenediamine hydrochloride slurry;

[0028] B), mixing m-xylylenediamine hydrochloride slurry with an organic phosphine compound having a structure of formula (I), reacting with solid phosgene after heating to obtain xylylene diisocyanate;

[0029]

[0030] Among them, R 1 , R 2 with R 3 each independently selected from C1-C10 alkyl or aryl.

[0031] The present invention adopts a one-pot method to synthesize xylylene diisocyanate, and the process route is simple to synthesize. By adding an organic phosphine compound, the reaction rate and conversion rate of m-xylylenediamine hydrochloride are improved, and the production cycle is shortened. The content is reduced, and the yield is obviously improved. ...

Embodiment 1

[0044] In a 500mL flask with a reflux cooler, a thermometer, an air duct and a stirrer, add 135g of dehydrated chlorobenzene and 10g of m-xylylenediamine, then blow in 7g of hydrogen chloride at 60-65°C for 1 hour to obtain m-phenylenedi Methylamine hydrochloride; after blowing in hydrogen chloride, add 1g of triphenylphosphine to the system, and then add BTC-chlorobenzene solvent dropwise after heating up to 132°C, in which BTC43.67g, chlorobenzene87.3g, dropwise time 3 ~3.5 hours; Then keep warm for half an hour, blow into 1.5 hours nitrogen to blow off excessive phosgene and hydrogen chloride; Filter and remove a small amount of unreacted hydrochloride 0.54g (dry weight), the filtrate of gained is carried out desolvent rectification, obtains 13.22 g of m-xylylene diisocyanate with a purity of 99.20%, and a yield of 94.8%. In addition, the obtained m-xylylene diisocyanate had a chromaticity of 25.

Embodiment 2

[0046] In a 1000mL flask with a reflux cooler, a thermometer, an air duct and a stirrer, add 405g of dehydrated o-dichlorobenzene and 30g of m-xylylenediamine, then blow in 18g of hydrogen chloride at 60-65°C for 1 hour to obtain m- Xylylenediamine hydrochloride; after blowing in hydrogen chloride, add 1.5g of triphenylphosphine to the system, raise the temperature to 145°C and add BTC-o-dichlorobenzene solvent dropwise, of which BTC65.5g, o-dichlorobenzene 131g, dripping time 5~5.5 hours; Then keep warm for half an hour, blow in nitrogen gas for 1.5 hours to blow off excess phosgene and hydrogen chloride; filter and remove a small amount of unreacted m-xylylenediamine hydrochloride 0.69g (dry weight), The resulting filtrate is subjected to desolvation rectification to obtain 40.09g of m-xylylene diisocyanate with a purity of 98.60%, and the yield is 95.3% at this time; .

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Abstract

The invention provides a preparation method of methylene diphenyl diisocyanate. The method comprises the following steps: performing a salt forming reaction on m-xylylenediamine and hydrogen chloride gas to obtain m-xylylenediamine hydrochloride; mixing the m-xylylenediamine hydrochloride, an organic phosphorus compound and solid phosgene for reaction to obtain methylene diphenyl diisocyanate. In a process of preparing methylene diphenyl diisocyanate, according to the application, an organic phosphorus compound additive is introduced, so that the reaction of m-xylylenediamine hydrochloride is promoted, therefore, the reaction rate and the effective conversion rate are improved.

Description

technical field [0001] The invention relates to the technical field of isocyanates, in particular to a preparation method of xylylene diisocyanate. Background technique [0002] Xylylene diisocyanate (XDI) in the isocyanate compound, because it introduces an alkylene group between the benzene ring and the isocyanate group, makes the polyurethane product non-yellowing, so it has excellent weather resistance and color stability. And adhesion, is gradually becoming a new star in the field of high-end optical resins. [0003] In the prior art, the reaction of organic primary amines and phosgene in an inert solvent is widely used to prepare isocyanates. The phosgene method can be divided into a direct method and a salt-forming method. The direct method is to directly react the primary amine with phosgene to obtain the corresponding isocyanate; the salt-forming method first reacts the corresponding amine with an acid gas such as hydrogen chloride, carbon dioxide, etc. to obtain a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/10C07C265/14
CPCC07C209/00C07C263/10C07C265/14C07C211/27
Inventor 高艳丽马韵升包英范江涛张建林易先君杨姗刘英贤魏政
Owner SHANDONG EFIRM BIOCHEMISTRY & ENVIRONMENTAL PROTECTION CO LTD
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