GB773462A - Improvements in or relating to the manufacture of melamine - Google Patents
Improvements in or relating to the manufacture of melamineInfo
- Publication number
- GB773462A GB773462A GB20070/55A GB2007055A GB773462A GB 773462 A GB773462 A GB 773462A GB 20070/55 A GB20070/55 A GB 20070/55A GB 2007055 A GB2007055 A GB 2007055A GB 773462 A GB773462 A GB 773462A
- Authority
- GB
- United Kingdom
- Prior art keywords
- melamine
- cyanamide
- calcium
- glycol
- calcium carbonate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D251/00—Heterocyclic compounds containing 1,3,5-triazine rings
- C07D251/02—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings
- C07D251/12—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
- C07D251/26—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with only hetero atoms directly attached to ring carbon atoms
- C07D251/40—Nitrogen atoms
- C07D251/54—Three nitrogen atoms
- C07D251/56—Preparation of melamine
- C07D251/60—Preparation of melamine from urea or from carbon dioxide and ammonia
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D251/00—Heterocyclic compounds containing 1,3,5-triazine rings
- C07D251/02—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings
- C07D251/12—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
- C07D251/26—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with only hetero atoms directly attached to ring carbon atoms
- C07D251/40—Nitrogen atoms
- C07D251/54—Three nitrogen atoms
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Phenolic Resins Or Amino Resins (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Melamine is prepared by carrying out the following reaction scheme: (a) calcium cyanamide is prepared from lime and hydrocyanic acid according to the known reaction: CaO + 2HCN -\sY CaCN2 + CO + H2; (b) the calcium cyanamide is converted into cyanamide and calcium carbonate by hydrolysis and carbonation according to the known reaction: CO2 + H2O + CaCN2 -\sY CaCO3 + H2CN2; (c) the cyanamide is polymerized to melamine by the action of heat according to the known reaction: 3H2CN2 -\sY (H2CN2)3; (d) the calcium carbonate produced by step (b) is decomposed into lime and carbon dioxide and these are recycled for use in steps (a) and (b) respectively. The hydrolysis of the calcium cyanamide in step (b) is preferably carried out in presence of a water-miscible organic solvent such as diethylene glycol, the water required is preferably injected as steam simultaneously with the carbon dioxide, and the calcium carbonate produced may be removed from the glycol solution of cyanamide by centrifuging. The glycol solution of cyanamide is preferably polymerized to melamine by heating it under pressure to a temperature of 220 DEG C., preferably after the addition of ammonia gas to the solution. The resulting solution of melamine may be expanded and cooled to precipitate the melamine and to liberate the major part of the ammonia. The melamine may be extracted by centrifuging and the glycol and recovered ammonia may be recycled to the polymerization step (c).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR773462X | 1954-07-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB773462A true GB773462A (en) | 1957-04-24 |
Family
ID=9197739
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB20070/55A Expired GB773462A (en) | 1954-07-09 | 1955-07-11 | Improvements in or relating to the manufacture of melamine |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB773462A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104163439A (en) * | 2014-06-13 | 2014-11-26 | 宁夏宝马化工集团有限公司 | Synthetic method of cyanamide aqueous solution by using sodium hydroxide |
| CN107473241A (en) * | 2017-09-06 | 2017-12-15 | 山东益丰生化环保股份有限公司 | A kind of preparation method of solid cyanamide |
| CN107500314A (en) * | 2017-09-06 | 2017-12-22 | 山东益丰生化环保股份有限公司 | A kind of preparation method of cyanamide organic solution |
-
1955
- 1955-07-11 GB GB20070/55A patent/GB773462A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104163439A (en) * | 2014-06-13 | 2014-11-26 | 宁夏宝马化工集团有限公司 | Synthetic method of cyanamide aqueous solution by using sodium hydroxide |
| CN107473241A (en) * | 2017-09-06 | 2017-12-15 | 山东益丰生化环保股份有限公司 | A kind of preparation method of solid cyanamide |
| CN107500314A (en) * | 2017-09-06 | 2017-12-22 | 山东益丰生化环保股份有限公司 | A kind of preparation method of cyanamide organic solution |
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