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Synthetic method of malononitrile

A synthesis method and a technology of malononitrile are applied in the chemical industry, and can solve the problems of volatility, complicated post-processing operations, and high viscosity of phosphorus-containing solid waste, and achieve simple post-processing, convenient storage and transportation, low cost and easy availability. The effect of stability

Inactive Publication Date: 2013-04-17
CHONGQING UNISPLENDOUR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In the preparation of malononitrile by the dehydration method of cyanoacetamide, the commonly used dehydrating agents are phosphorus oxychloride, phosphorus pentachloride and phosphorus pentoxide, but the use of the above dehydrating agents has the following disadvantages: a large amount of phosphorus containing solid waste, and these phosphorus-containing solid wastes are relatively viscous and easy to stick to the reactor wall. Usually, it is necessary to add carriers such as sodium chloride, diatomaceous earth, silica gel, and calcium chloride to the reaction system for adsorption, thereby further increasing The amount of solid waste generated; at the same time, these solid wastes need to be removed by filtration, centrifugation and other means after the reaction, which also makes the post-processing operation more cumbersome
Although this method does not produce phosphorus-containing solid waste, and the obtained by-product cyanuric acid can be used as antifouling agent or marine insecticide, it still needs to filter and separate the by-product, and the post-treatment operation is still relatively complicated, and the dehydrating agent cyanuric chloride is in the air. Medium unstable, volatile, inconvenient for storage and transportation

Method used

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  • Synthetic method of malononitrile

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Add 16.8g (0.2mol) of cyanoacetamide, 3mL (0.039mol) of N,N-dimethylformamide and 100mL of acetonitrile into a four-neck flask equipped with mechanical stirring, a thermometer and a constant pressure dropping funnel, and heat up to 80 ℃; Dissolve 24g (0.08mol) triphosgene in 40mL toluene to form a homogeneous solution, then add the solution dropwise to the aforementioned four-neck flask at a constant speed, and the dropwise addition is completed in 3 to 4 hours; then, reflux for 8 hours, and the reaction Tail gas carbon dioxide and hydrogen chloride that produce are absorbed with sodium hydroxide solution, HPLC analysis cyanoacetamide content is 0.3%, finish reaction, be down to room temperature, use residual hydrogen chloride gas and phosgene in the reaction solution of nitrogen purging, distillation recovery solvent, again in Under reduced pressure distillation at a vacuum of -0.095MPa, the fraction with a boiling point of 105-115°C was collected to obtain 10.10 g of m...

Embodiment 2

[0024] Add 16.8g (0.2mol) cyanoacetamide, 4g (0.04mol) triethylamine and 100mL toluene to the four-neck flask as described in Example 1, and raise the temperature to 80°C; dissolve 24g (0.08mol) triphosphine Form a homogeneous solution in 40mL of toluene, then add the solution dropwise to the aforementioned four-neck flask at a constant speed, and the dropwise addition is completed in 3-4 hours; then, reflux for 8 hours, and the tail gas carbon dioxide and hydrogen chloride produced by the reaction are washed with sodium hydroxide The solution was absorbed, and the content of cyanoacetamide was 0.5% according to HPLC analysis. After the reaction was completed, the temperature was lowered to room temperature, and the residual hydrogen chloride gas and phosgene in the reaction solution were purged with nitrogen, and the solvent was recovered by distillation, and then depressurized under the condition of vacuum degree of -0.095MPa After distillation, the fraction with a boiling po...

Embodiment 3

[0026] Add 16.8g (0.2mol) cyanoacetamide, 0.5g (0.0085mol) sodium chloride and 100mL acetonitrile to the four-neck flask as described in Example 1, and heat up to 80°C; 24g (0.08mol) triphosgene Dissolve in 40mL of toluene to form a homogeneous solution, then add the solution dropwise to the aforementioned four-necked bottle at a constant speed, and the dropwise addition is completed in 3-4 hours; then, reflux for 10 hours, and the tail gas carbon dioxide and hydrogen chloride produced by the reaction are oxidized with hydrogen Sodium solution suction, HPLC analysis cyanoacetamide content is 0.46%, finishes the reaction, cools down to room temperature, purging residual hydrogen chloride gas and phosgene in the reaction solution with nitrogen, distills and recovers the solvent, then decomposes under the vacuum degree of -0.095MPa. Distilled under high pressure to collect fractions with a boiling point of 105-115°C to obtain 7.51 g of malononitrile. The purity by GC analysis was ...

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Abstract

The invention discloses a synthetic method of malononitrile. Cyanoacetamide reacts with triphosgene in the presence of a catalyst to synthesize malononitrile, wherein the catalyst is any one substance or a mixture of multiple substances selected from N,N-dimethyl formamide, sodium chloride, pyridine and triethylamine. The method provided by the invention employs the triphosgene as a dehydrating agent, and the triphosgene is low in cost, available and high in stability, and facilitates storage and transportation; the reaction products of the cyanoacetamide and the triphosgene only include carbon dioxide and hydrogen chloride gases except for the malononitrile, without solid waste, and therefore, after the reaction is completed, the steps of removing the solid waste by means of filtering, centrifuging and the like are not needed; the reaction mixture is directly subjected to reduced pressure distillation after the solvent is recovered so that the malononitrile having the purity of higher than 98% can be obtained; and the posttreatment is simple.

Description

technical field [0001] The invention belongs to the field of chemical industry and relates to a synthesis method of malononitrile. Background technique [0002] Malononitrile is an important raw material for organic synthesis and an important intermediate for the synthesis of drugs (such as vitamin B1, triamterene, adenine, etc.) . At the same time, malononitrile also has important uses in synthetic dyes, metal anticorrosion, and resin crosslinking agents. [0003] There are many synthetic methods of malononitrile, including cyanoacetamide dehydration method, allene oxidation ammonolysis method, acetonitrile cyanamide gas phase method, acetonitrile high temperature pyrolysis method, acrylonitrile and aminoacetonitrile method, etc. Among them, the cyanoacetamide dehydration method is a common method for synthesizing malononitrile because of its simple route, cheap and easy-to-obtain raw materials, mild reaction conditions, low process requirements, simple equipment, and few...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C255/04C07C253/20
Inventor 丁永良李艳陈修毅何咏梅王欣李静罗丹李君
Owner CHONGQING UNISPLENDOUR CHEM
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