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Synthesis method of malononitrile

A synthesis method and technology of malononitrile, applied in the preparation of chlorohydrate, carbonate/acid carbonate, preparation of carboxylic acid amide dehydration, etc., can solve the problem of poor reaction effect, increased cost, and a large amount of solid waste and other problems, to achieve the effect of reducing the cost of raw materials, improving product yield and quality, and reducing the cost of raw material synthesis

Active Publication Date: 2018-03-23
HEBEI JIUTIAN MEDICINE CHEM CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problems existing in the existing synthesis process that a large amount of catalyst needs to be added, the cost is increased, the reaction produces a large amount of solid waste, and the reaction effect is poor, the present invention provides a synthesis method of malononitrile

Method used

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preparation example Construction

[0013] The embodiment of the present invention provides a kind of synthetic method of malononitrile, the synthetic method of this malononitrile at least comprises the following steps:

[0014] (1) Mix the solvent, cyanoacetamide, phosphorus oxychloride and solid phosgene to obtain a suspension, heat up to 50-90° C., and perform a heat preservation reaction to obtain a malononitrile solution;

[0015] (2) subjecting the malononitrile solution to an elevated temperature distillation process, reclaiming the solvent and phosphorus oxychloride, and obtaining a distillation residue;

[0016] (3) The distillation residue is subjected to vacuum distillation to obtain malononitrile.

[0017] Preferably, the solvent is at least one of 1,2-dichloroethane, phosphorus oxychloride, chlorinated aromatics and other inert solvents, among which 1,2-dichloroethane, chlorobenzene and trichloro Phosphorus, more preferably 1,2-dichloroethane, and phosphorus oxychloride, phosphorus oxychloride acts...

Embodiment 1

[0030] A kind of synthetic method of malononitrile, comprises the steps:

[0031] (1) Add 42.04g (0.5mol) of cyanoacetamide, 300mL of 1,2-dichloroethane, and 76.67g (0.5mol) of phosphorus oxychloride into a four-neck flask equipped with a mechanical stirrer, a thermometer, and a condensation absorption device With 59.37g (0.2mol) of solid phosgene, the temperature was raised to 70-73°C, and the reaction was kept for 7-10 hours;

[0032] (2) The gas generated by the reaction passes through anhydrous CaCl 2 After drying, absorb with water and saturated sodium carbonate solution in sequence. The remaining tail gas after absorption is detected as neutral and discharged directly. After the heat preservation is completed, recover 1,2-dichloroethane at normal pressure to 95°C, and then gradually increase the vacuum to recover 100 Fraction before ℃ / -0.098MPa (mainly phosphorus oxychloride);

[0033] (3) Recover 29.93g of malononitrile product between 118~120°C, the purity is 99.3%, ...

Embodiment 2

[0035] A kind of synthetic method of malononitrile, comprises the steps:

[0036] (1) Add 42.02g (0.5mol) of cyanoacetamide, 300mL of 1,2-dichloroethane, and 115.03g (0.75mol) of phosphorus oxychloride into a four-necked flask equipped with a mechanical stirrer, a thermometer, and a condensation absorption device With 74.30g (0.25mol) of solid phosgene, the temperature was raised to 60-63°C, and the reaction was kept for 6-8 hours;

[0037] (2) The gas generated by the reaction passes through anhydrous CaCl 2 After drying, it is absorbed with water and saturated sodium carbonate solution in sequence, and the remaining tail gas after absorption is detected as neutral and discharged directly. After the heat preservation is over, recover 1,2-dichloroethane under normal pressure to 95°C, then gradually increase the vacuum to recover the fraction before 100°C / -0.098MPa (mainly phosphorus oxychloride);

[0038] (3) Recover 30.31g of malononitrile product between 118~120°C, the pur...

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Abstract

The invention relates to the technical field of malononitrile synthesis, and particularly discloses a synthesis method of malononitrile. The synthesis method of the malononitrile comprises the following steps: performing mixing treatment on a solvent, cyanoacetamide, phosphoryl chloride and solid phosgene to obtain suspension, heating to 50 to 90 DEG C, and performing heat-preservation reaction toobtain a malononitrile solution; performing heating distillation treatment on the malononitrile solution, recycling the solvent and the phosphoryl chloride to obtain a distillation residue; performing vacuum reduced pressure distillation treatment on the distillation residue to obtain the malononitrile. The synthesis method of the malononitrile has the advantages of simple process, convenient operation and low cost; the phosphoryl chloride and the solid phosgene are adopted as a mixed dehydrating agent, so that the yield and the quality of a product are greatly improved, and production of solid wastes is avoided.

Description

technical field [0001] The invention relates to the technical field of malononitrile synthesis, in particular to a synthesis method of malononitrile. Background technique [0002] Malononitrile (Malonitrile) is also known as dicyanomethane, cyanoacetonitrile, etc. In the molecular structure of malononitrile, there are 5 active centers including cyano carbon, nitrogen and methylene, so it has a very wide range of applications in chemical synthesis, such as the synthesis of pharmaceutical products cefotetan, olanzapine, dexime Nil, 2-aminonicotinonitrile, milrinone, etc.; dyes and luminescent material intermediates naphthalene tetracarboxylic acid, 2-methyl-6-tert-butyl-4-dicyanomethenyl-4H-pyran, etc.; and Pesticides such as bensulfuron-methyl, rimsulfuron-methyl, nicosulfuron, bispyribac, etc. have a very large market demand. [0003] It is understood that there are currently two methods for the synthesis of malononitrile: gas-phase method and liquid-phase method. The synt...

Claims

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Application Information

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IPC IPC(8): C07C253/20C07C255/04C01B7/01C01D7/10C01B32/60
CPCC01B7/015C01D7/10C07C253/20C07C255/04
Inventor 杨国忠郭婷婷时叶强董璞曹彤彤
Owner HEBEI JIUTIAN MEDICINE CHEM CO LTD
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