Preparation method of N-phenylmaleimide (PMI)

A maleimide and phenyl technology, applied in the field of preparation of N-phenylmaleimide, can solve the problems of complex process, difficult reaction, troublesome filtration steps, etc., and achieves simple preparation method and improved yield and purity, energy and time savings

Inactive Publication Date: 2013-10-30
JIH NONG SCI
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Problems solved by technology

[0003] The N-phenylmaleimide of the prior art is synthesized by maleic anhydride (maleic anhydride, MA) and aniline (aniline), but the manufacturing process is complicated, and the yield is low and the purity is not high, for example China Taiwan Invention Patent No. 29955 discloses the use of ammonium salt as a catalyst to prepare N-phenylmaleimide, but the reaction is difficult due to poor solubility, and metal compounds must be added during the manufacturing process, making the process cost higher; the United States Patent No. 5136052 discloses that aniline, maleic anhydride and organic acid are mixed and then filtered to remove catalyst and impurities, wherein the filtration step is quite troublesome; other documents point out that in the presence of catalyst, N-phenylmaleic acid N-phenylmaleamic acid (N-phenylmaleamic acid) reacts with oxalyl chloride to produce hy

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  • Preparation method of N-phenylmaleimide (PMI)

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[0019] The preparation method of N-phenylmaleimide provided by the invention is as figure 1 shown, including the following steps:

[0020] Firstly, the catalyst, the organic solvent, the polymerization inhibitor and the maleic anhydride are mixed and stirred in the reactor and heated to the first reaction temperature and the first reaction time to form the maleic anhydride mixture;

[0021] Add aniline to the heat-treated maleic anhydride mixture in a continuous amount, and reflux dehydration at the same time. After the reaction is completed, add sodium carbonate for acid-base neutralization, and then obtain N - phenylmaleimide.

[0022] The preparation method of N-phenylmaleimide provided by the present invention will be further illustrated by the following examples, and these examples do not limit the content disclosed above in the present invention.

Embodiment 1

[0024] In a 1-liter four-necked bottle, add 400 milliliters (ml) of toluene, 1 mole (mole), that is, 98 grams (g) of maleic anhydride, 4 g of p-toluenesulfonic acid, 2 g of dimethylformamide and 0.5 g of Methoxyhydroquinone, heated at 115°C to 125°C to completely dissolve the powder to form a maleic anhydride mixture; then gradually add 1 mole (93g) of aniline in 4 times within 0.5 hours to 1 hour Add the heat-treated maleic anhydride mixture, and carry out reflux dehydration simultaneously; After the reaction is completed, add 5g of sodium carbonate (Na 2 CO 3 ) for acid-base neutralization, stirred for 10 minutes to 30 minutes, so that the pH value (pH value) was between 6 and 7, left to stand to be separated, then washed the toluene layer with water and crystallized by cooling, to obtain 155g and a purity of 98% N-phenylmaleimide.

Embodiment 2

[0026] Add 400ml of toluene, 1 mole (98g) of maleic anhydride, 5g of phosphoric acid carrier, 2g of dimethylformamide and 0.5g of methoxyhydroquinone to a 1-liter four-neck bottle, After heating at ℃ to make the powder completely dissolve, a maleic anhydride mixture is formed; then gradually add 1 mole (93 g) of aniline to the heat-treated maleic anhydride mixture in 4 times within 0.5 hours to 1 hour, and Simultaneously carry out reflux dehydration; after the reaction is completed, add 5g of sodium carbonate for acid-base neutralization, stir for 10 minutes to 30 minutes, make the pH (pH value) between 6 and 7, let stand to be separated, and then wash the toluene layer And cooled and crystallized to obtain 138g of N-phenylmaleimide with a purity of 98%.

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Abstract

The invention provides a preparation method of N-phenylmaleimide (PMI). The preparation method comprises the following steps of: mixing and stirring a catalyst, an organic solvent, a polymerization inhibitor and maleic anhydride (MA) into a reaction kettle, and carrying out heat treatment on the mixture at the first reaction temperature for a first reaction time to form an MA mixture; then, continuously adding aniline into the heat-treated MA mixture in quantity, meanwhile, reflowing and dehydrating, and carrying out acid base neutralization; and layering, washing, cooling and crystallizing to obtain the N-PMI with high yield and purity.

Description

technical field [0001] The present invention relates to a method for preparing N-phenylmaleimide (N-phenylmaleimide, PMI), especially a method for preparing high-yield and high-purity N-phenylmaleimide . Background technique [0002] N-phenylmaleimide (PMI) is a raw material for organic synthesis, which can be embedded in polymer chains to increase the internal rotation resistance between chains, thereby improving the heat resistance of materials. At present, N-phenylmaleimide is often used as a heat-resistant modifier of acrylonitrile-butadiene-styrene resin (acrylonitrile butadiene styrene resin, ABS resin), which can improve the performance of acrylonitrile-butadiene-styrene resin. The softening point can improve its heat resistance, and the modified acrylonitrile-butadiene-styrene resin is impact-resistant, so it can replace some engineering plastics and can be used in the automotive industry. In addition, N-phenylmaleimide can also be used as a polypropylene (polyprop...

Claims

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Application Information

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IPC IPC(8): C07D207/448
Inventor 陈奕瀚陈鸿文刘汉滨
Owner JIH NONG SCI
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