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Clean production method for continuously synthesizing hydantoin

A production method and chemical synthesis technology, which are applied in the field of continuous chemical synthesis of hydantoin clean production, can solve the problems of product quality and device operation stability, automation control production difficulties, incomplete solution of environmental protection problems, etc., and achieve the suppression of harmful impurities. Generate, easy to automate control, improve the effect of investment utilization

Inactive Publication Date: 2015-09-02
李宽义
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  • Application Information

AI Technical Summary

Problems solved by technology

[0014] For the above various production methods of hydantoin, there are defects such as low product quality, low yield, high production cost, and incomplete solution to environmental protection problems in the production process.
In particular, these processes cannot truly achieve continuous industrial production, either by adopting batch synthesis in pressure vessel reactors, "trickle bed" reactions, or using a combination of tubular reactors and tank reactors for semi-continuous synthesis. The investment is relatively large, and it is very difficult to adopt automatic control production, so there are problems in product quality and device operation stability

Method used

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  • Clean production method for continuously synthesizing hydantoin
  • Clean production method for continuously synthesizing hydantoin
  • Clean production method for continuously synthesizing hydantoin

Examples

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Effect test

Embodiment 1

[0037] Example 1: 37% formaldehyde solution was used to absorb purified hydrocyanic acid gas to obtain 500 g / l aqueous solution of hydroxyacetonitrile; ammonia, carbon dioxide, and water were prepared in a molar ratio of 1:1:10 to prepare a carbon dioxide ammonia water reaction system.

[0038] Continuously feed the above carbon dioxide and ammonia water system into the preheater with a pressure metering pump at a feed rate of 4T / hour, preheat the material temperature to 90°C, and inject the material into the first part of the combined continuous reactor: the volume is 200L A tube test reactor with an inner diameter of 65 mm and a tube length of about 60 meters. The material enters from the inlet end; at about 1.0 meters from the material inlet end, another plunger metering pump is used to feed the hydroxyacetonitrile aqueous solution at a rate of 400 kg / hour. Feed speed Continuous feed is mixed and reacted with the preheated carbon dioxide and ammonia water reaction system. Th...

Embodiment 2

[0039] Example 2: Absorb purified hydrocyanic acid gas with 37% formaldehyde solution to prepare a 500 g / l aqueous solution of hydroxyacetonitrile; ammonia, carbon dioxide, and water are prepared in a molar ratio of 1:1:10 to prepare a carbon dioxide ammonia water reaction system.

[0040] The above carbon dioxide and ammonia water system is continuously fed into the preheater with a pressure metering pump at a feed rate of 2T / hour, the temperature of the preheated material is 85°C, and the material is injected into the first part of the combined continuous reactor: the volume is 200L The tube test reactor, the inner diameter of the tube is 65 mm, the tube length is about 60 meters, and the material enters from the inlet end; at 1.0 meters from the material inlet end, a plunger metering pump is used to feed the hydroxyacetonitrile aqueous solution at a rate of 200 kg / hour The speed continuous feeding is mixed and reacted with the preheated carbon dioxide and ammonia water react...

Embodiment 3

[0041] Example 3: 37% formaldehyde solution was used to absorb purified hydrocyanic acid gas to obtain 500 g / l aqueous solution of hydroxyacetonitrile; ammonia, carbon dioxide, and water were prepared in a molar ratio of 1:1:10 to prepare a carbon dioxide ammonia water reaction system.

[0042] The above carbon dioxide and ammonia water system is continuously fed into the preheater with a pressure metering pump at a feed rate of 4T / hour, the temperature of the preheated material is 80°C, and the material is injected into the first part of the combined continuous reactor: the volume is 200L The tube test reactor, the inner diameter of the tube is 65 mm, the tube length is about 60 meters, and the material enters from the inlet end; at 1.0 meters from the material inlet end, a plunger metering pump is used to feed the hydroxyacetonitrile aqueous solution at a rate of 400 kg / hour The speed continuous feeding is mixed and reacted with the preheated carbon dioxide and ammonia water ...

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Abstract

* An environmentally-friendly clean production method for continuously synthesizing hydantoin comprises the following steps: reacting an initial raw material hydrocyanic acid with formaldehyde to generate hydroxyacetonitrile, reacting hydroxyacetonitrile in a carbon dioxide and ammonia water system through a continuous reactor to obtain an aqueous solution of hydantoic acid, carrying out acid hydrolysis to obtain hydantoin crystals, and purifying to obtain a highly pure hydantoin product. The combined continuous reactor is adopted to synthesize hydantoin, so the device investment is highly effectively reduced, and the investment efficiency is improved by times; automatic control is very conveniently controlled, the continuity and the stability of production are well guaranteed, the labor cost is saved, and the safe production operationality of the whole process is guaranteed; generation of harmful impurities is well inhibited, decomposition and polymerization of hydroxyacetonitrile and other side reactions are effectively inhibited, and the purity and the yield of the above obtained product are improved; and the method has lower requirements of raw materials, fully and comprehensively utilizes resources, is an environmentally friendly clean production technology, and plays a very active synergistic role in natural environment protection.

Description

technical field [0001] A clean production method for continuously synthesizing hydantoin, which relates to a production method for synthesizing hydantoin with hydrocyanic acid-hydroxyacetonitrile method, especially relates to an environmentally friendly and clean production process for hydantoin as a raw material for pesticides and pharmaceutical intermediates, and belongs to organic synthesis Production methods of intermediate raw materials. Background technique [0002] Hydantoin, also known as hydantoin, is an important basic organic raw material widely used in pesticide, pharmaceutical and other industries. The basic preparation methods of hydantoin mainly include the following: [0003] (1), Urech in 1873 through the condensation reaction of alanine sulfate and potassium cyanate. This method is called Urech hydantoin synthesis. Glycine or ethyl glycine can also be used instead of alanine. [0004] (2) Acetone cyanohydrin reacts with ammonium carbonate to obtain 5,5-d...

Claims

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Application Information

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IPC IPC(8): C07D233/74
CPCC07D233/74
Inventor 李宽义朱喜福曾雯娟龙智李俊白先丽
Owner 李宽义
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