CN104176746A - Synthetic method of cyanamide aqueous solution from sodium sulfate - Google Patents
Synthetic method of cyanamide aqueous solution from sodium sulfate Download PDFInfo
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- CN104176746A CN104176746A CN201410262748.9A CN201410262748A CN104176746A CN 104176746 A CN104176746 A CN 104176746A CN 201410262748 A CN201410262748 A CN 201410262748A CN 104176746 A CN104176746 A CN 104176746A
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- sodium sulfate
- sodium
- aqueous solution
- cyanamide
- lime nitrogen
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Abstract
The invention relates to a synthetic method of a cyanamide aqueous solution from sodium sulfate. The method comprises the following steps: (1) adding lime nitrogen into a sodium sulfate aqueous solution to enable lime nitrogen and sodium sulfate to react to generate sodium hydrogen cyanamide; (2) filtering to remove calcium hydroxide and part of sodium hydrogen sulfate; (3) neutralizing sodium hydrogen cyanamide by hydrochloric acid; and (4) concentrating under reduced pressure to remove sodium chloride and sodium hydrogen sulfate. The invention relates to a brand new method for industrially synthesizing the cyanamide aqueous solution. According to the method, the raw materials are easy to obtain, the reaction condition is mild, the byproducts can be comprehensively utilized, no exhaust gases are generated, the process is simple and the cost is low. The method overcomes the defects of the existing method that byproducts are more, the catalyst is expensive, raw materials are huge in toxicity and strong in corrosivity, the temperature is high, the feeding speed is hard to increase and high-purity carbon dioxide is depended and the like.
Description
technical field:
The present invention relates to Chemical Engineering Technology, particularly a kind of sodium sulfate synthetic method of the cyanamide aqueous solution.
background technology:
Cyanamide molecular formula is NH
2cN, it has very high solubleness and is weakly alkaline in water, in the time of 43 DEG C and water dissolve each other completely, owing to containing active group cyano group and amino, therefore easily there is the reactions such as addition, replacement, condensation.Cyanamide solution is used as defoliant, the nontoxic insecticide of fruit fruit tree abroad.Crystal cyanamide is mainly used in medicine, healthcare product, synthesizing of fodder additives and synthesizing of pesticide intermediate, has many uses general.
In cyanamide preparation method, there are many reports both at home and abroad, wherein the method for main report has following four kinds:
1, urea method (Wyler's process)
2, prussic acid method
3, ammonia process
4, lime nitrogen method
Front 3 kinds of methods all need the hot conditions of 300 ~ 800 DEG C, and the cyanamide by product of preparation is many, and adopt very expensive catalyzer; Especially the raw materials used toxicity of prussic acid method is very large, and processing condition are difficult to control, and are difficult to realize suitability for industrialized production, also do not have the report of suitability for industrialized production aspect at present.Generally the production method of application is lime nitrogen method both at home and abroad at present, this technique comparative maturity.
Lime nitrogen claims again calcium cyanamide, and as alkaline-earth metal cyanamide compound, the cyanamide aqueous solution is all prepared by domestic all producers using lime nitrogen as raw material.
Domestic south adopts respectively sulfuric acid process and carbonic acid gas hydrolysis decalcification to prepare the cyanamide aqueous solution because data is different with resource with the north especially the Northwest.
The shortcoming of sulfuric acid process is: corrodibility is strong, and because strong acid is met, alkalescence is large compared with strong material (lime nitrogen suspension) reaction generation heat, difficult control of temperature.In operation, be difficult to improve rate of feeding, and need a large amount of cooling water temperature to ensure reaction conditions, if control badly, easily form dicyandiamide polymer.
Carbon dioxide process: because the use of the source of carbonic acid gas (carbon dioxide) is progressively restricted, the by-product carbon dioxide that most of manufacturing enterprise all adopts various types of limestone kilns or other products to produce in producing is produced the cyanamide aqueous solution through collection and treatment.The shortcoming of the method is: carbon dioxide purity is low, impurity is many.In order to meet manufacturing technique requirent, have to adopt the whole bag of tricks to carry out purifying and concentrate to carbon dioxide, make equipment investment strengthen and in reaction process, carbonic acid gas need become gaseous state from solid-state, liquid state, makes complex operation, has increased operation easier.Carbonic acid gas is under normal pressure simultaneously, and in water, solubleness is less, and the weak acid of formation is difficult in time strong alkaline aqueous solution PH be reduced.Under alkaline condition, the easy polymerization of cyanamide that hydrolysis forms forms dicyandiamide polymer, and the rate of feeding of the lime nitrogen that for this reason can only slow down in technique ensures processing condition, thereby reduces production capacity and plant factor.For the rate of feeding of accelerating lime nitrogen will improve carbon dioxide purity on the one hand, improve draft speed, also to strengthen cooling installation, on the other hand, retort internal pressure can not be too high, if pressure is high, poor stability.Otherwise utilization rate of carbon dioxide reduces, waste is serious.
summary of the invention:
Given this, be necessary to design and be a kind ofly suitable for suitability for industrialized production and low cost, nontoxic, pollution-free, by product is few and be easy to the cyanamide Syntheses in water method reclaiming.
A sodium sulfate synthetic method for the cyanamide aqueous solution, comprises the following steps:
sodium sulfate is added to the water and stirs and make its dissolving; In aqueous sodium persulfate solution, add lime nitrogen, lime nitrogen is reacted with sodium sulfate and generate cyanamide hydrogen sodium; Because lime nitrogen solubleness in water is little, and lime nitrogen charging time is short, therefore lime nitrogen is hydrolyzed lacking of carrying out, it is mainly to react with sodium sulfate, and reaction equation is:
CaCN
2+Na
2SO
4+2H
2O
NaHCN
2+NaHSO
4+Ca(OH)
2 ；
by step
product filter, remove calcium hydroxide and part of sulfuric acid hydrogen sodium and other solid impurities, sodium pyrosulfate solubleness in water is lower;
will be through step
the filtrate obtaining is used in hydrochloric acid and de-sodium, and reaction equation is:
NaHCN
2+HCL
NH
2CN+NaCL ；
will be through step
the solution decompression obtaining is concentrated, and slough sodium-chlor and sodium pyrosulfate and obtain the cyanamide aqueous solution, wherein, and the moisture reusable edible of concentrating under reduced pressure evaporation, sodium-chlor and sodium pyrosulfate can conveniently be recycled.
Preferably, step
the mol ratio of middle lime nitrogen and sodium sulfate is 1:1 ~ 1:1.1, and the temperature of reaction of lime nitrogen and sodium sulfate is 0 ~ 40 DEG C, and the reaction times is 8 ~ 16h.
Preferably, step
it is 4.5 ~ 6 that middle reaction is performed until pH value.
Preferably, step
the weight ratio of middle sodium sulfate and water is 1:4.
The present invention is the method for the synthetic cyanamide aqueous solution of a kind of brand-new industry, its raw material easily obtains, reaction conditions gentleness, by product can fully utilize, without waste gas produce, the simple cost of technique is low, broken away from that in existing method, by product is many, catalyzer is expensive, material toxicity is large, corrodibility is strong, temperature is high-leveled and difficult with shortcomings such as raising rate of feeding and the dependences to high-pureness carbon dioxide.
embodiment:
A sodium sulfate synthetic method for the cyanamide aqueous solution, comprises the following steps:
sodium sulfate is added to the water and stirs and make its dissolving; In aqueous sodium persulfate solution, add lime nitrogen, lime nitrogen is reacted with sodium sulfate and generate cyanamide hydrogen sodium; Because lime nitrogen solubleness in water is little, and lime nitrogen charging time is short, therefore lime nitrogen is hydrolyzed lacking of carrying out, it is mainly to react with sodium sulfate, and reaction equation is:
CaCN
2+Na
2SO
4+2H
2O
NaHCN
2+NaHSO
4+Ca(OH)
2 ；
by step
product filter, remove calcium hydroxide and part of sulfuric acid hydrogen sodium and other solid impurities, sodium pyrosulfate solubleness in water is lower;
will be through step
the filtrate obtaining is used in hydrochloric acid and de-sodium, and reaction equation is:
NaHCN
2+HCL
NH
2CN+NaCL ；
will be through step
the solution decompression obtaining is concentrated, and slough sodium-chlor and sodium pyrosulfate and obtain the cyanamide aqueous solution, wherein, and the moisture reusable edible of concentrating under reduced pressure evaporation, sodium-chlor and sodium pyrosulfate can conveniently be recycled, and this is ripe prior art, is not repeated.
In the present embodiment, step
the mol ratio of middle lime nitrogen and sodium sulfate is 1:1 ~ 1:1.1, and the temperature of reaction of lime nitrogen and sodium sulfate is 0 ~ 40 DEG C, and the reaction times is 8 ~ 16h.Step
it is 4.5 ~ 6 that middle reaction is performed until pH value.Step
the weight ratio of middle sodium sulfate and water is 1:4.
Claims (4)
1. a sodium sulfate synthetic method for the cyanamide aqueous solution, is characterized in that: comprise the following steps:
sodium sulfate is added to the water and stirs and make its dissolving; In aqueous sodium persulfate solution, add lime nitrogen, lime nitrogen is reacted with sodium sulfate and generate cyanamide hydrogen sodium, reaction equation is:
CaCN
2+Na
2SO
4+2H
2O
NaHCN
2+NaHSO
4+Ca(OH)
2 ；
by step
product filter, remove calcium hydroxide and part of sulfuric acid hydrogen sodium;
will be through step
the filtrate obtaining is used in hydrochloric acid and de-sodium, and reaction equation is:
NaHCN
2+HCL
NH
2CN+NaCL ；
will be through step
the solution decompression obtaining is concentrated, sloughs sodium-chlor and sodium pyrosulfate and obtains the cyanamide aqueous solution.
2. the sodium sulfate synthetic method of the cyanamide aqueous solution as claimed in claim 1, is characterized in that: step
the mol ratio of middle lime nitrogen and sodium sulfate is 1:1 ~ 1:1.1, and the temperature of reaction of lime nitrogen and sodium sulfate is 0 ~ 40 DEG C, and the reaction times is 8 ~ 16h.
3. the sodium sulfate synthetic method of the cyanamide aqueous solution as claimed in claim 1, is characterized in that: step
it is 4.5 ~ 6 that middle reaction is performed until pH value.
4. the sodium sulfate synthetic method of the cyanamide aqueous solution as claimed in claim 1, is characterized in that: step
the weight ratio of middle sodium sulfate and water is 1:4.
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| CN201410262748.9A CN104176746A (en) | 2014-06-13 | 2014-06-13 | Synthetic method of cyanamide aqueous solution from sodium sulfate |
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|---|---|---|---|
| CN201410262748.9A CN104176746A (en) | 2014-06-13 | 2014-06-13 | Synthetic method of cyanamide aqueous solution from sodium sulfate |
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|---|---|
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Family
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110697734A (en) * | 2019-11-29 | 2020-01-17 | 山东益丰生化环保股份有限公司 | Preparation method for continuously synthesizing phosphorus-free cyanamide |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101016151A (en) * | 2006-08-08 | 2007-08-15 | 芮海平 | Method of preparing cyanamide aqueous solution and dicyandiamide and coproducing carbon and calcium carbonate by calcium cyanamide |
-
2014
- 2014-06-13 CN CN201410262748.9A patent/CN104176746A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101016151A (en) * | 2006-08-08 | 2007-08-15 | 芮海平 | Method of preparing cyanamide aqueous solution and dicyandiamide and coproducing carbon and calcium carbonate by calcium cyanamide |
Non-Patent Citations (3)
| Title |
|---|
| 汪涛锋: "单氰胺 氰胺类精细化工产品中间体第二报", 《杭州化工》, no. 4, 31 December 1988 (1988-12-31), pages 17 - 21 * |
| 申泮文等: "《化合物词典》", 30 June 2002, article "氰氨化钠", pages: 173 * |
| 韩长日等: "《精细有机化工产品生产技术手册》", 30 June 2010, article "2.223 氨基胍碳酸盐", pages: 1256 - 2.223 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110697734A (en) * | 2019-11-29 | 2020-01-17 | 山东益丰生化环保股份有限公司 | Preparation method for continuously synthesizing phosphorus-free cyanamide |
| CN110697734B (en) * | 2019-11-29 | 2023-01-20 | 益丰新材料股份有限公司 | Preparation method for continuously synthesizing phosphorus-free cyanamide |
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Application publication date: 20141203 |
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