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Method for synthesizing N-phenylmaleimide through catalysis of acid ionic liquid

A technology of acidic ionic liquid and maleimide, which is applied in the field of catalytic synthesis of N-phenylmaleimide by acidic ionic liquid, can solve the problems of inability to reuse and be difficult to remove, and achieves low production cost and high yield. The effect of good rate and cost reduction

Inactive Publication Date: 2012-04-04
WUHAN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The most used in industrial production is the azeotropic method to prepare N-phenylmaleimide. In the reaction of dehydration and ring closure, inorganic acids (such as: phosphoric acid, concentrated sulfuric acid, p-toluenesulfonic acid, phosphorus pentoxide, etc.) are used. ) as a catalyst, its disadvantage is that it cannot be reused and it is difficult to completely remove it from the product

Method used

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  • Method for synthesizing N-phenylmaleimide through catalysis of acid ionic liquid

Examples

Experimental program
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Effect test

Embodiment 1

[0022] According to the traditional method for preparing quaternary ammonium salt ionic liquids, triethylamine is added to a three-necked flask with a thermometer and a constant pressure dropping funnel, and concentrated sulfuric acid is added dropwise to it under ice bath conditions, and the rate of addition is controlled to keep the temperature of the system. Below 10°C, continue to react at below 10°C for two hours after the dropwise addition is completed. Filter after completion of the reaction, and the filtrate is rotary evaporated to obtain a brown viscous liquid, which is recorded as 1 # Quaternary ammonium salt ionic liquid catalyst.

[0023] With 50g of N-phenylmaleimide acid, 80g of toluene and 3 grams of the above 1 # Add the quaternary ammonium salt ionic liquid catalyst together to a 250ml three-necked flask equipped with a stirrer, a water separator and a reflux condenser, then add 0.25 grams of 2,6 di-tert-butylphenol, heat to boiling, and keep the temperature ...

Embodiment 2

[0025] Add 1 mol of choline chloride and 2 mol of zinc chloride into a closed three-necked flask with a thermometer, stir, and react at 60°C for 1 hour to obtain a colorless viscous liquid, which is recorded as 2 # Quaternary ammonium salt ionic liquid catalyst.

[0026] With 50g of N-phenylmaleimide acid, 80g of toluene and 8 grams of the above-mentioned 2 # Add the quaternary ammonium salt ionic liquid catalyst into a 250ml three-necked flask equipped with a stirrer, a water separator and a reflux condenser, then add 0.3 grams of triphenyl phosphite, and heat to boiling. At this time, the temperature is 112°C. Next, divide water while heating. After two hours, the water level in the water separator no longer rises. At this time, the reaction ends, and the liquid in the three-necked flask is layered. The upper layer is light yellow, and the lower layer is dark yellow oily. Pour off the upper liquid, and use 3% NaHCO 3 The aqueous solution is washed to neutrality, washed wit...

Embodiment 3

[0028] Add a certain amount of methanol into a closed three-necked flask with a thermometer, weigh one part of tetramethylammonium bromide and one part of sodium bisulfate, and stir at 40°C for 24 hours under a constant temperature magnetic stirrer. Filter, and the filtrate is rotary evaporated to obtain a yellow viscous liquid, which is recorded as 3 # catalyst.

[0029] With 50g of N-phenylmaleimide acid, 85g xylene and 15 grams of the above-mentioned 3 # Catalyst is added in the 250ml there-necked flask that agitator, water separator and reflux condenser are housed, add 0.25 gram of hydroquinone again, be heated to boiling, this moment temperature is 120 ℃, divide water while heating at this temperature, After two hours, the water level in the water separator no longer rises, and the reaction ends now, and the liquid in the three-necked flask is layered, the upper layer is light yellow, and the lower layer is dark yellow oily. Pour off the upper liquid, and use 3% NaHCO ...

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Abstract

The invention relates to a method for synthesizing N-phenylmaleimide, which comprises the following steps of: adding N-phenyl maleamic acid, an organic solvent, an acid ionic liquid catalyst and a polymerization inhibitor into a reaction container, performing cyclodehydration, pouring reaction liquid into a weakly alkaline aqueous solution, washing until neutrality, washing with water, and performing rotary evaporation by using a rotary evaporator to obtain crude N-phenylmaleimide; and adding cyclohexane into the obtained crude N-phenylmaleimide, extracting by controlling the temperature to be between 40 and 80DEG C, and cooling and filtering to obtain the N-phenylmaleimide. The prepared target product has high purity and yield and low production cost. The acid ionic liquid can be recycled, and is suitable for industrial production. The catalyst and the solvent in the synthesis process can be recycled, three wastes are reduced, and the cost is reduced; and through detection of gas chromatography and high performance liquid chromatography, the purity of the product is over 97 percent and the yield of the product is about 97 percent.

Description

technical field [0001] The invention relates to a method for catalytically synthesizing N-phenylmaleimide with an acidic ionic liquid. Background technique [0002] The earliest application of N-phenylmaleimide (NPMI) was as an underwater antifouling agent, which has very low toxicity to fish, does not pollute water quality, and has no corrosive effect on metals and equipment. NPMI-modified ABS resin not only has greatly improved heat resistance, but also maintains good processability, compatibility and impact resistance. At the same time, NPMI can also be used as optical raw materials (polymers of NPMI and styrene can be used to synthesize photosensitive resins), and pharmaceutical intermediates (NPMI is an important organic intermediate, which can synthesize carbazole-3,4- Dicarboxyl imide and phenylpyrrole carbazole, etc., have the effect of inhibiting cytotoxicity and antitumor). At present, the synthesis of NPMI using aniline and maleic anhydride has achieved industri...

Claims

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Application Information

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IPC IPC(8): C07D207/448
Inventor 袁军魏宇
Owner WUHAN INSTITUTE OF TECHNOLOGY
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