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Method for producing 5,5-dimethyl hydantoin

A technology of dimethyl hydantoin and production method, which is applied in the production field of 5,5-dimethyl hydantoin, can solve the problems of low yield, difficult control and the like, and achieves low reaction temperature, easy control and short time. Effect

Inactive Publication Date: 2012-07-25
祝莉宁
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, the patent No. 200610038040.0 discloses a production method for preparing 5,5-dimethylhydantoin, but the yield is low and difficult to control

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The production method of 5,5-dimethylhydantoin of the present invention is to be prepared by following steps by weight parts:

[0017] a. Mix 600-800 parts of ammonium bicarbonate and 500-700 parts of acetone cyanohydrin with water and stir to fully dissolve, and seal it when heated to 10°C;

[0018] b. Add 30 to 50 parts of ammonia gas into the material obtained in step a, slowly heat to 50 to 65°C, keep the temperature constant for 1 to 2 hours, and stir;

[0019] c. Heating the substance prepared in step b to 75-85°C, inducing wind for 30-50 minutes, then cooling to room temperature and filtering to obtain the crude dimethylhydantoin and mother liquor;

[0020] d. Add 950-1150 parts of the crude dimethylhydantoin produced in step c to 150-300 parts of water and 700-900 parts of the mother liquor mixture, stir while adding, heat to 80-98°C and add activated carbon 3 to 8 parts, decolorized for 20 to 40 minutes, filtered to remove activated carbon, then cooled to crys...

Embodiment 2

[0022] The production method of 5,5-dimethylhydantoin of the present invention is to be prepared by following steps by weight parts:

[0023] a. Mix 700 parts of ammonium bicarbonate and 600 parts of acetone cyanohydrin with water and stir to fully dissolve, and seal when heated to 10°C;

[0024] b. Then feed 40 parts of ammonia gas into the substance obtained in step a, slowly heat to 60°C, keep the temperature constant for 2 hours, and stir;

[0025] c. Heating the substance prepared in step b to 80°C, inducing wind for 40 minutes, cooling to room temperature, and filtering to obtain the crude dimethylhydantoin and mother liquor;

[0026] d. Put 1,050 parts of the crude dimethylhydantoin produced in step c into a mixture of 200 parts of water and 800 parts of mother liquor, stir while adding, add 5 parts of activated carbon after heating to 95°C, and decolorize for 30 minutes. Filtrate to remove active carbon, then cool and crystallize, centrifugally filter, and dry to obta...

Embodiment 3

[0028] The production method of 5,5-dimethylhydantoin of the present invention is to be prepared by following steps by weight parts:

[0029] a. Mix 600 parts of ammonium bicarbonate and 500 parts of acetone cyanohydrin with water and stir to fully dissolve, and seal when heated to 10°C;

[0030] b. Add 30 parts of ammonia gas to the material obtained in step a, slowly heat to 50°C, keep the temperature constant for 1.5 hours, and stir;

[0031] c. Heating the substance prepared in step b to 75° C., inducing wind for 30 minutes, cooling to room temperature, and filtering to obtain the crude dimethylhydantoin and mother liquor;

[0032] d. Put 950 parts of the crude dimethylhydantoin produced in step c into a mixture of 150 parts of water and 700 parts of mother liquor, stir while adding, add 3 parts of activated carbon after heating to 90°C, and decolorize for 20 minutes. Filtrate to remove active carbon, then cool and crystallize, centrifugally filter, and dry to obtain the ...

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PUM

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Abstract

The invention discloses a method for producing 5,5-dimethyl hydantoin which is prepared from the following substances in parts by weight according to the steps as follows: adding water to ammonium bicarbonate and acetone cyanohydrin, stirring until the ammonium bicarbonate and the acetone cyanohydrin are fully dissolved, and sealing up while heating up to 10 DEG C; introducing ammonia to the mixture, heating slowly to 50-65 DEG C, stirring, heating up to 75-85 DEG C after keeping temperature constant for 1-2 hours, introducing air for 30-50 minutes, and filtering after cooling to a room temperature, thus obtaining crude dimethyl hydantoin and a mother liquid; and putting the crude dimethyl hydantoin into the mixture of water and the mother liquid while stirring, adding active carbon afterheating up to 80-98 DEG C, decolouring, removing the active carbon by filtration, recooling, crystallizing, filtering centrifugally, and drying, thus obtaining the finished product of dimethyl hydantoin. The method has the advantages of simple technological reaction, low reaction temperature, short reaction time, less side reaction and high yield reaching 85%, and is easy to control; the raw material of ammonium bicarbonate applicable to the method belongs to chemical fertilizers, and is easy to obtain; and the filtrate produced by the technology can be used repeatedly, and no three wastes are discharged.

Description

technical field [0001] The invention relates to a production method of 5,5-dimethylhydantoin. Background technique [0002] 5,5-Dimethylhydantoin, also known as 5,5-dimethylhydantoin (hereinafter referred to as DMH). [0003] DMH is an important and widely used intermediate in organic synthesis, and it is a heterocyclic compound with a certain rigid skeleton. A series of valuable derivatives can be prepared by substitution reactions. Such as: dibromohydantoin, dichlorohydantoin, etc. are widely used in organic synthesis, medicine, plastics, food, cosmetics, pesticides and other production fields. [0004] DMH has been produced industrially abroad in the 1970s, and the United States, Britain and Switzerland have all built production facilities with an annual output of thousands of tons. Japan also has production, but the scale is only 600 tons per year. [0005] Our country only started research in this area in the early 1990s, and realized industrialized production, whic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D233/74
Inventor 马振宇王洁马琳祝莉宁
Owner 祝莉宁
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