CN115703744A - Preparation method of 5,5-dimethylhydantoin - Google Patents
Preparation method of 5,5-dimethylhydantoin Download PDFInfo
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- CN115703744A CN115703744A CN202111357473.3A CN202111357473A CN115703744A CN 115703744 A CN115703744 A CN 115703744A CN 202111357473 A CN202111357473 A CN 202111357473A CN 115703744 A CN115703744 A CN 115703744A
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- Prior art keywords
- dimethylhydantoin
- acetone cyanohydrin
- ammonia water
- cyclization reaction
- carbon dioxide
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- YIROYDNZEPTFOL-UHFFFAOYSA-N 5,5-Dimethylhydantoin Chemical compound CC1(C)NC(=O)NC1=O YIROYDNZEPTFOL-UHFFFAOYSA-N 0.000 title claims abstract description 58
- 238000002360 preparation method Methods 0.000 title claims abstract description 20
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 48
- MWFMGBPGAXYFAR-UHFFFAOYSA-N 2-hydroxy-2-methylpropanenitrile Chemical compound CC(C)(O)C#N MWFMGBPGAXYFAR-UHFFFAOYSA-N 0.000 claims abstract description 36
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 32
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 32
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 24
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 24
- 238000007363 ring formation reaction Methods 0.000 claims abstract description 23
- 239000012452 mother liquor Substances 0.000 claims abstract description 16
- 238000002156 mixing Methods 0.000 claims abstract description 15
- 239000012295 chemical reaction liquid Substances 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 25
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 18
- 230000008569 process Effects 0.000 claims description 13
- 238000011282 treatment Methods 0.000 claims description 11
- 238000002425 crystallisation Methods 0.000 claims description 10
- 230000008025 crystallization Effects 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 238000001035 drying Methods 0.000 claims description 7
- 238000005119 centrifugation Methods 0.000 claims description 6
- 238000004042 decolorization Methods 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims 1
- 239000000645 desinfectant Substances 0.000 abstract description 3
- 238000006243 chemical reaction Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000005086 pumping Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000013078 crystal Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000004659 sterilization and disinfection Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OMJKWVKPIOIQDM-UHFFFAOYSA-N 3-bromo-1-chloroimidazolidine-2,4-dione Chemical compound ClN1CC(=O)N(Br)C1=O OMJKWVKPIOIQDM-UHFFFAOYSA-N 0.000 description 1
- MENYRYNFSIBDQN-UHFFFAOYSA-N 5,5-dibromoimidazolidine-2,4-dione Chemical compound BrC1(Br)NC(=O)NC1=O MENYRYNFSIBDQN-UHFFFAOYSA-N 0.000 description 1
- ZKLFRQSZDUSMQE-UHFFFAOYSA-N 5,5-dichloroimidazolidine-2,4-dione Chemical compound ClC1(Cl)NC(=O)NC1=O ZKLFRQSZDUSMQE-UHFFFAOYSA-N 0.000 description 1
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 1
- 102000004190 Enzymes Human genes 0.000 description 1
- 108090000790 Enzymes Proteins 0.000 description 1
- 208000007212 Foot-and-Mouth Disease Diseases 0.000 description 1
- 241000710198 Foot-and-mouth disease virus Species 0.000 description 1
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- 206010040880 Skin irritation Diseases 0.000 description 1
- 241000607479 Yersinia pestis Species 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- 238000009360 aquaculture Methods 0.000 description 1
- 244000144974 aquaculture Species 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 235000005911 diet Nutrition 0.000 description 1
- 230000037213 diet Effects 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 239000003651 drinking water Substances 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000002070 germicidal effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 244000144972 livestock Species 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000003755 preservative agent Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 230000036556 skin irritation Effects 0.000 description 1
- 231100000475 skin irritation Toxicity 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 230000009182 swimming Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/141—Feedstock
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the technical field of disinfectant preparation, in particular to a preparation method of 5,5-dimethylhydantoin. The invention provides a preparation method of 5,5-dimethylhydantoin, which comprises the following steps: mixing acetone cyanohydrin, carbon dioxide and ammonia water to perform cyclization reaction, and crystallizing the obtained cyclization reaction liquid to obtain 5,5-dimethylhydantoin and mother liquor; vacuum concentrating the mother liquor to obtain 5,5-dimethylhydantoin; the acetone cyanohydrin and NH in the ammonia water 3 The molar ratio of (A) is less than or equal to 1. The preparation method can lead the yield of 5,5-dimethylhydantoin to reach more than 93 percent.
Description
Technical Field
The invention relates to the technical field of disinfectant preparation, in particular to a preparation method of 5,5-dimethylhydantoin.
Background
5,5-dimethylhydantoin, collectively known as 5,5-dimethylimidazoledione, also known as 5,5-dimethylhydantoin. Molecular formula C 5 H 8 N 2 O 2 Molecular weight is 128.13.5,5-dimethylhydantoin and its derivatives (such as dichlorohydantoin, dibromohydantoin, bromochlorohydantoin, etc.) are very effective germicidal disinfectants, have the advantages of small smell, mild action, good stability, no skin irritation, low price, long shelf life, etc., and are widely applied to the disinfection of agriculture (aquaculture, livestock foot and mouth disease control, pest control, fruit preservatives, crop enzyme disease control, etc.), daily chemical industry, medical sanitation disinfection, drinking water, diet, swimming pools, entertainment venues, circulating cooling water systems, etc.
Currently, 5,5-dimethylhydantoin synthesis is commonly performed using the Buherner-Belgers (Bonherer-Bergs) cyclization process, the earliest used raw materials being acetone cyanohydrin and ammonium carbonate. The production can also take place batchwise or continuously with acetone cyanohydrin, carbon dioxide and liquid nitrogen. For the production process of the batch method by adopting acetone cyanohydrin, carbon dioxide and liquid nitrogen, the production process of the batch method is simpler, but the total yield is only 85 percent, and the batch method is not suitable for large-scale industrial production.
Disclosure of Invention
The invention aims to provide a preparation method of 5,5-dimethylhydantoin, and the yield of the preparation method can reach more than 93%.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of 5,5-dimethylhydantoin, which comprises the following steps:
mixing acetone cyanohydrin, carbon dioxide and ammonia water to perform cyclization reaction, and crystallizing the obtained cyclization reaction liquid to obtain 5,5-dimethylhydantoin and mother liquor;
vacuum concentrating the mother liquor to obtain 5,5-dimethylhydantoin;
the acetone cyanohydrin and NH in the ammonia water 3 The molar ratio of (A) is less than or equal to 1.
Preferably, the acetone cyanohydrin and NH in ammonia water 3 In a molar ratio of 1: (1.65-2.2).
Preferably, the mixing comprises the steps of:
acetone cyanohydrin and ammonia water are mixed, and carbon dioxide is introduced under stirring.
Preferably, the molar ratio of acetone cyanohydrin to carbon dioxide is 1: (1.2-2.5).
Preferably, the temperature of the cyclization reaction is 45-60 ℃ and the time is 2-5 h.
Preferably, the method further comprises the following steps of: carrying out vacuum suction on the cyclization reaction solution;
the temperature of the vacuum pumping is 80-90 ℃, and the time is 0.9-1.2 h.
Preferably, the temperature of the crystallization is 15 to 20 ℃.
Preferably, the crystallization and vacuum concentration further comprise: carrying out post-treatment on the 5,5-dimethyl hydantoin to obtain a 5,5-dimethyl hydantoin pure product;
the post-treatment comprises decolorization, cooling, centrifugation and drying which are sequentially carried out.
Preferably, the decoloring treatment includes the steps of:
mixing the 5,5-dimethylhydantoin, activated carbon and water, decoloring and filtering.
Preferably, the mass ratio of the 5,5-dimethylhydantoin to the activated carbon is 100: (0.8-1.5);
the temperature of the decolorization is 65-75 ℃, and the time is 0.8-1.5 h.
The invention provides a preparation method of 5,5-dimethylhydantoin, which comprises the following steps: mixing acetone cyanohydrin, carbon dioxide and ammonia water to perform cyclization reaction, and crystallizing the obtained cyclization reaction liquid to obtain 5,5-dimethylhydantoin and mother liquor; vacuum concentrating the mother liquor to obtain 5,5-dimethylhydantoin; the acetone cyanohydrin and NH in the ammonia water 3 The molar ratio of (1) is less than or equal to 1.65. According to the invention, the side reaction (hydrolysis reaction of acetone cyanohydrin) in the cyclization reaction process is reduced by increasing the using amount of ammonia water, and the reaction of acetone cyanohydrin, carbon dioxide and ammonia water can maximally generate forward reaction, so that the yield of 5,5-dimethylhydantoin is increased, and the yield of 5,5-dimethylhydantoin is more than 93%.
Detailed Description
The invention provides a preparation method of 5,5-dimethylhydantoin, which comprises the following steps:
mixing acetone cyanohydrin, carbon dioxide and ammonia water to perform cyclization reaction, and crystallizing the obtained cyclization reaction liquid to obtain 5,5-dimethylhydantoin and mother liquor;
vacuum concentrating the mother liquor to obtain 5,5-dimethylhydantoin;
the acetone cyanohydrin and NH in the ammonia water 3 The molar ratio of (1) is less than or equal to 1.65.
In the present invention, all the starting materials for the preparation are commercially available products well known to those skilled in the art, unless otherwise specified.
Mixing acetone cyanohydrin, carbon dioxide and ammonia water to perform cyclization reaction, and crystallizing the obtained cyclization reaction liquid to obtain 5,5-dimethylhydantoin and mother liquor; the acetone cyanohydrin and NH in the ammonia water 3 The molar ratio of (A) is less than or equal to 1.
In the present invention, the purity of the acetone cyanohydrin is preferably not less than 97%; the mass concentration of the ammonia water is preferably 20-30%, and more preferably 30%; the purity of the carbon dioxide is preferably more than or equal to 95 percent.
In the present invention, the molar ratio of acetone cyanohydrin and carbon dioxide is preferably 1: (1.2 to 2.5), more preferably 1: (1.5-2.0).
In the present invention, the acetone cyanohydrin and NH in the ammonia water 3 1.65, preferably 1: (1.65 to 2.2), more preferably 1: (1.7-2.0).
In the present invention, the mixing preferably comprises the steps of: acetone cyanohydrin and ammonia water are mixed, and carbon dioxide is introduced under stirring. The mixing of the acetone cyanohydrin and the ammonia water is not limited in any way, and the acetone cyanohydrin and the ammonia water can be uniformly mixed by adopting the process well known by the technical personnel in the field. In a specific embodiment of the present invention, the acetone cyanohydrin and the ammonia water are specifically mixed for 30min. The stirring process is not particularly limited, and may be performed by a method known to those skilled in the art. In the present invention, the introduction rate of carbon dioxide is preferably 0.3 to 0.5mol/h.
In the present invention, the temperature of the cyclization reaction is preferably 45 to 60 ℃, more preferably 48 to 56 ℃, and most preferably 50 to 53 ℃; the time is preferably 2 to 5 hours, more preferably 3 to 4 hours. In the present invention, since the reaction of acetone cyanohydrin, carbon dioxide, and ammonia water is an exothermic reaction, it is preferable to reduce the temperature of the reaction system with water at normal temperature in order to maintain the cyclization reaction within the above temperature range.
In the present invention, the principle of the cyclization reaction is shown in formula 1:
before the crystallization, the present invention preferably further comprises: and (3) carrying out vacuum suction on the cyclization reaction solution. In the present invention, the temperature of the vacuum suction is preferably 80 to 90 ℃, more preferably 82 to 87 ℃, and most preferably 85 to 86 ℃; the time for the vacuum suction is preferably 0.9 to 1.2 hours, more preferably 1.0 to 1.1 hours.
In the invention, the vacuum pumping is used for gasifying and pumping away excessive ammonia water, carbon dioxide and water, thereby improving the purity and yield of the product.
In the present invention, the temperature of the crystallization is preferably 15 to 20 ℃, more preferably 16 to 18 ℃; the time for the crystallization is not particularly limited in the present invention, and a time known to those skilled in the art is used until no more crystals are precipitated.
After the crystallization is completed, the present invention preferably further comprises centrifugation, and the centrifugation process is not particularly limited in the present invention and may be performed by a process well known to those skilled in the art.
After 5,5-dimethylhydantoin and mother liquor are obtained, the mother liquor is concentrated in vacuum to obtain 5,5-dimethylhydantoin.
The process of vacuum concentration is not limited in any way, and the solvent in the mother liquor can be completely evaporated and removed by adopting a process well known to those skilled in the art.
The invention also preferably comprises after the crystallization and vacuum concentration: and carrying out post-treatment on the 5,5-dimethylhydantoin to obtain a 5,5-dimethylhydantoin pure product. In the present invention, the post-treatment preferably includes decoloring treatment, cooling, centrifugation and drying, which are sequentially performed.
In the present invention, the decoloring treatment preferably includes the steps of:
mixing the 5,5-dimethylhydantoin, activated carbon and water, decoloring and filtering.
In the present invention, the mass ratio of 5,5-dimethylhydantoin to the activated carbon is preferably 100: (0.8 to 1.5), more preferably 100: (0.9 to 1.3), most preferably 100: (1.0-1.2).
In the present invention, the mass ratio of 5,5-dimethylhydantoin to water is preferably 1: (0.5 to 1.2), more preferably 1:1.
In the present invention, the temperature of the decolorization is preferably 65 to 75 ℃, more preferably 68 to 72 ℃, and most preferably 70 ℃; the time is preferably 0.8 to 1.5 hours, more preferably 1.0 to 1.3 hours.
The filtering process is not limited in any way, and the activated carbon in the system obtained after the decolorization treatment can be removed by adopting a process well known to a person skilled in the art.
In the present invention, the temperature after the cooling is preferably 15 to 20 ℃, more preferably 16 to 18 ℃; the cooling is a crystallization process, namely 5,5-dimethylhydantoin in the solution is precipitated in a cooling mode.
The centrifugation process is not particularly limited in the present invention, and may be performed by a process known to those skilled in the art.
In the present invention, the temperature of the drying is preferably 100 ℃; the drying time is not limited in any way, and the drying time is up to the constant weight of 5,5-dimethylhydantoin, which is well known to a person skilled in the art.
The preparation of 5,5-dimethylhydantoin provided by the present invention is described in detail below with reference to the following examples, which should not be construed as limiting the scope of the present invention.
Note: the mass ratio or molar ratio of each substance in examples 1 to 9 and comparative example 1 is understood that the technical scheme of the invention has no special limitation on the weight grade of the preparation raw materials, and can be laboratory grade (for example, the mass unit can be 'mg' or 'g'), industrial grade (for example, the mass unit can be 'kg' or't'), and the like.
Examples 1 to 9
Fully mixing acetone cyanohydrin (the purity is more than or equal to 97%) and ammonia water (the mass concentration is 30%) for 30min, introducing carbon dioxide (the purity is more than or equal to 95%) at the speed of 0.5mol/h under the condition of stirring, cooling the obtained system by normal-temperature water, maintaining the temperature of the system at 60 ℃, performing cyclization reaction for 2h, heating to 85 ℃, performing vacuum suction for 1h, cooling to 18 ℃, precipitating crystals, and centrifuging to obtain 5,5-dimethylhydantoin and mother liquor;
vacuum concentrating the mother liquor to obtain 5,5-dimethylhydantoin;
mixing the obtained 5,5-dimethylhydantoin, pure water and activated carbon, wherein the mass ratio of 5,5-dimethylhydantoin to pure water to activated carbon is 1.2; decolorizing at 70 deg.C for 1h, filtering, cooling to 18 deg.C, centrifuging, and drying at 100 deg.C to constant weight to obtain 5,5-dimethyl hydantoin pure product; wherein the acetone cyanohydrin and NH in ammonia water 3 The molar ratio of the raw materials to carbon dioxide, the yield of the 5,5-dimethyl hydantoin pure product and the indexes (purity, pH value and melting point) of the 5,5-dimethyl hydantoin pure product are shown in Table 1;
comparative example 1
The preparation process is referred to examples 1 to 10, with the difference that only the acetone cyanohydrin, NH in ammonia water 3 Different from carbon dioxide in molar ratio, and NH in the acetone cyanohydrin and ammonia water 3 And carbon dioxide, and the yields and indices (purity, pH and melting point) of the 5,5-dimethylhydantoin pure product obtained from the preparation process shown in comparative example 1 are shown in table 1:
TABLE 1 acetone cyanohydrin, NH in Ammonia Water in examples 1 to 10 and comparative example 1 3 The molar ratio of the product to carbon dioxide and the index of the pure 5,5-dimethylhydantoin obtained by the preparation
As can be seen from Table 1, the yield of 5,5-dimethylhydantoin can be effectively increased by increasing the amount of ammonia water, and the 5,5-dimethylhydantoin prepared by the method also has higher purity.
It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention.
Claims (10)
1. A preparation method of 5,5-dimethylhydantoin is characterized by comprising the following steps:
mixing acetone cyanohydrin, carbon dioxide and ammonia water to perform cyclization reaction, and crystallizing the obtained cyclization reaction liquid to obtain 5,5-dimethylhydantoin and mother liquor;
vacuum concentrating the mother liquor to obtain 5,5-dimethylhydantoin;
the acetone cyanohydrin and NH in the ammonia water 3 The molar ratio of (A) is less than or equal to 1.
2. The process according to claim 1, wherein the acetone cyanohydrin and NH in aqueous ammonia are used 3 In a molar ratio of 1: (1.65-2.2).
3. The method of claim 1, wherein the mixing comprises the steps of:
acetone cyanohydrin and ammonia water are mixed, and carbon dioxide is introduced under stirring.
4. The method according to claim 1, wherein the molar ratio of acetone cyanohydrin to carbon dioxide is 1: (1.2-2.5).
5. The process according to any one of claims 1 to 4, wherein the temperature of the cyclization reaction is 45 to 60 ℃ and the time is 2 to 5 hours.
6. The method according to claim 1, further comprising, before the crystallization: carrying out vacuum suction on the cyclization reaction solution;
the temperature of the vacuum suction is 80-90 ℃, and the time is 0.9-1.2 h.
7. The production method according to claim 1 or 6, wherein the temperature of the crystallization is 15 to 20 ℃.
8. The method of claim 1, wherein the steps of crystallizing and vacuum concentrating further comprise: carrying out post-treatment on the 5,5-dimethyl hydantoin to obtain a 5,5-dimethyl hydantoin pure product;
the post-treatment comprises decolorization, cooling, centrifugation and drying which are sequentially carried out.
9. The method of claim 8, wherein the decoloring treatment comprises the steps of:
mixing the 5,5-dimethylhydantoin, activated carbon and water, decoloring and filtering.
10. The method of claim 9, wherein the mass ratio of 5,5-dimethylhydantoin to the activated carbon is 100: (0.8-1.5);
the temperature of the decolorization is 65-75 ℃, and the time is 0.8-1.5 h.
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| CN202111357473.3A CN115703744A (en) | 2021-11-16 | 2021-11-16 | Preparation method of 5,5-dimethylhydantoin |
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| CN202111357473.3A CN115703744A (en) | 2021-11-16 | 2021-11-16 | Preparation method of 5,5-dimethylhydantoin |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1803775A (en) * | 2006-01-23 | 2006-07-19 | 周新基 | Method for preparing 5,5-dimethylhydantion |
| CN102002000A (en) * | 2010-11-18 | 2011-04-06 | 大庆井井源油田科技开发有限公司 | Method for producing 5,5-dimethyl hydantoin |
| CN104557721A (en) * | 2014-12-30 | 2015-04-29 | 沈阳化工研究院有限公司 | Method for producing 5,5-dimethylhydantoin |
| CN108148000A (en) * | 2018-03-20 | 2018-06-12 | 河北鑫淘源环保科技有限公司 | A kind of preparation method of 5,5 Dimethyl Hydan |
| CN111606857A (en) * | 2020-05-14 | 2020-09-01 | 龙智 | Clean production process for continuously synthesizing hydantoin |
| CN111675656A (en) * | 2020-07-20 | 2020-09-18 | 河北利仕化学科技有限公司 | Continuous production method of bromochlorohydantoin |
-
2021
- 2021-11-16 CN CN202111357473.3A patent/CN115703744A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1803775A (en) * | 2006-01-23 | 2006-07-19 | 周新基 | Method for preparing 5,5-dimethylhydantion |
| CN102002000A (en) * | 2010-11-18 | 2011-04-06 | 大庆井井源油田科技开发有限公司 | Method for producing 5,5-dimethyl hydantoin |
| CN104557721A (en) * | 2014-12-30 | 2015-04-29 | 沈阳化工研究院有限公司 | Method for producing 5,5-dimethylhydantoin |
| CN108148000A (en) * | 2018-03-20 | 2018-06-12 | 河北鑫淘源环保科技有限公司 | A kind of preparation method of 5,5 Dimethyl Hydan |
| CN111606857A (en) * | 2020-05-14 | 2020-09-01 | 龙智 | Clean production process for continuously synthesizing hydantoin |
| CN111675656A (en) * | 2020-07-20 | 2020-09-18 | 河北利仕化学科技有限公司 | Continuous production method of bromochlorohydantoin |
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