Preparation method for MXDI

An organic solvent and solution technology, applied in the field of preparation of organic compounds, can solve the problems of easy generation of chlorinated substances and high free chlorine, and achieve the effect of shortening the production cycle

Inactive Publication Date: 2017-03-15
JIANGSU JIALONG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main disadvantage of this method is that it is easy to produce chlorinated substances, high free chlorine, etc.

Method used

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  • Preparation method for MXDI
  • Preparation method for MXDI

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Put 30g of m-xylylenediamine and 390g of o-dichlorobenzene into a 500ml four-neck flask equipped with stirring, thermometer, gas guide tube and condenser tube, raise the temperature to 125~130°C, and feed dry HCl gas while stirring, Adjust system pH=2~3. Raise the temperature to 135~140°C, pass phosgene under vigorous stirring, pass phosgene at 135~140°C for 2 hours, pass phosgene at 145~150°C for 2 hours, and finally pass phosgene at 155~160°C until the solution is transparent. Then cool down to 40~45°C, and pass through dry nitrogen for 2h. Then the solvent was removed under reduced pressure, and the pure product of MXDI was obtained by rectification under reduced pressure.

[0029] 33.6g of pure MXDI was obtained in the experiment, the content was 99.7% by gas spectrometry analysis, the single impurity was less than 0.2%, and the yield was 80.2%.

Embodiment 2

[0031] The process steps are the same as in Example 1, except that the feeding amount of m-xylylenediamine is 50 g, and that of o-dichlorobenzene is 650 g.

[0032] 57.3g of pure MXDI was obtained in the experiment, the content was 99.6% by gas spectrometry analysis, the single impurity was less than 0.2%, and the yield was 82%.

Embodiment 3

[0034] The process steps are the same as in Example 1, except that the feeding amount of n-xylylenediamine is 100 g, xylene is 1300 g, and benzyltriethylammonium chloride is 1 g.

[0035] 119.6g of pure MXDI was obtained in the experiment, the content was 99.8% by gas spectrometry analysis, and the yield was 85.6%.

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Abstract

The invention discloses a preparation method for MXDI. The preparation method comprises the following steps: dissolving m-xylylenediamine in an organic solvent and introducing acidic gas for salt formation; then carrying out a phosgenation reaction at a high temperature so as to obtain a solution of MXDI; and carrying out distillation for solvent removal and then carrying out rectification so as to obtain high-purity MXDI. According to the invention, MXDI is prepared by using a phosgene process; hydrochloride is prepared from m-xylylenediamine at first, so produced isocyanate and acyl chloride are prevented from reacting with amine again to produce a polymer compound in the phosgenation reaction; and a gradient heating manner is employed for the phosgenation reaction, so the method overcomes the disadvantages of proneness to production of chlorinated substances at a too high temperature and long reaction time at a too low temperature in a traditional phosgene process, shortens production period and prepares high-purity MXDI.

Description

technical field [0001] The present invention relates to a kind of preparation method of organic compound, especially a kind of preparation method of MXDI. Background technique [0002] MXDI is the abbreviation of m-xylylene diisocyanate. MXDI has excellent weather resistance, color stability and adhesion, and is mainly used in high-grade polyurethane coatings. Paints, spectacle lenses, flexible packaging, elastomers, leather and adhesives, etc. The traditional process of MXDI adopts the method of phosgenation into salt. The main disadvantage of this method is that it is easy to produce chlorinated substances and high free chlorine. Contents of the invention [0003] The purpose of the present invention is to provide a kind of preparation method of MXDI, the content of chlorinated substance is low, the purity is high, and free chlorine is low in the obtained product. [0004] The technical solution for realizing the object of the present invention is: a kind of preparati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C265/14C07C263/10C07C263/20
CPCC07C263/10C07C209/00C07C263/20C07C265/14C07C211/27
Inventor 杨佳佳张洪峰刘超牛安忠
Owner JIANGSU JIALONG CHEM
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