CN118307445A - Green preparation method of cyanamide-based methyl carbamate - Google Patents
Green preparation method of cyanamide-based methyl carbamate Download PDFInfo
- Publication number
- CN118307445A CN118307445A CN202410562172.1A CN202410562172A CN118307445A CN 118307445 A CN118307445 A CN 118307445A CN 202410562172 A CN202410562172 A CN 202410562172A CN 118307445 A CN118307445 A CN 118307445A
- Authority
- CN
- China
- Prior art keywords
- cyanamide
- methyl
- solution
- aqueous solution
- edta
- 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.)
- Pending
Links
- XZMCDFZZKTWFGF-UHFFFAOYSA-N Cyanamide Chemical compound NC#N XZMCDFZZKTWFGF-UHFFFAOYSA-N 0.000 title claims abstract description 76
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- GTCAXTIRRLKXRU-UHFFFAOYSA-N methyl carbamate Chemical compound COC(N)=O GTCAXTIRRLKXRU-UHFFFAOYSA-N 0.000 title claims description 6
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims abstract description 43
- 239000007864 aqueous solution Substances 0.000 claims abstract description 41
- 239000000243 solution Substances 0.000 claims abstract description 39
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000000706 filtrate Substances 0.000 claims abstract description 31
- 238000000909 electrodialysis Methods 0.000 claims abstract description 30
- MCLITRXWHZUNCQ-UHFFFAOYSA-N methylcyanamide Chemical compound CNC#N MCLITRXWHZUNCQ-UHFFFAOYSA-N 0.000 claims abstract description 30
- SNULTPQANPFFQH-UHFFFAOYSA-N 6-methoxy-1h-1,3,5-triazine-2,4-dione Chemical compound COC1=NC(=O)NC(=O)N1 SNULTPQANPFFQH-UHFFFAOYSA-N 0.000 claims abstract description 29
- MYFXBBAEXORJNB-UHFFFAOYSA-N calcium cyanamide Chemical compound [Ca+2].[N-]=C=[N-] MYFXBBAEXORJNB-UHFFFAOYSA-N 0.000 claims abstract description 26
- XMJHPCRAQCTCFT-UHFFFAOYSA-N methyl chloroformate Chemical compound COC(Cl)=O XMJHPCRAQCTCFT-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000011259 mixed solution Substances 0.000 claims abstract description 20
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 40
- 238000000034 method Methods 0.000 claims description 30
- 230000001276 controlling effect Effects 0.000 claims description 23
- 238000001914 filtration Methods 0.000 claims description 19
- 238000003756 stirring Methods 0.000 claims description 18
- 238000006243 chemical reaction Methods 0.000 claims description 16
- ZSYJMXLJNPEAGP-UHFFFAOYSA-N methyl n-cyanocarbamate Chemical compound COC(=O)NC#N ZSYJMXLJNPEAGP-UHFFFAOYSA-N 0.000 claims description 15
- 230000008569 process Effects 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 9
- 230000035484 reaction time Effects 0.000 claims description 4
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 229920000877 Melamine resin Polymers 0.000 claims 4
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims 4
- 239000000203 mixture Substances 0.000 claims 1
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 abstract description 20
- 229910001424 calcium ion Inorganic materials 0.000 abstract description 20
- 239000012535 impurity Substances 0.000 abstract description 17
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract description 15
- 229910001415 sodium ion Inorganic materials 0.000 abstract description 15
- 238000010668 complexation reaction Methods 0.000 abstract description 10
- 239000007788 liquid Substances 0.000 abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 9
- 239000003513 alkali Substances 0.000 abstract description 8
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 abstract description 5
- 230000015572 biosynthetic process Effects 0.000 abstract description 5
- 238000005516 engineering process Methods 0.000 abstract description 4
- 238000003786 synthesis reaction Methods 0.000 abstract description 4
- 239000003814 drug Substances 0.000 abstract description 2
- 239000000463 material Substances 0.000 abstract description 2
- 239000012528 membrane Substances 0.000 description 25
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 13
- 238000000926 separation method Methods 0.000 description 9
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 8
- 229910052757 nitrogen Inorganic materials 0.000 description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 239000002699 waste material Substances 0.000 description 6
- 230000009471 action Effects 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 238000006460 hydrolysis reaction Methods 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 238000007086 side reaction Methods 0.000 description 3
- 230000002194 synthesizing effect Effects 0.000 description 3
- QLLOYLKVIMXSDM-UHFFFAOYSA-N C(N)(O)=O.C(C)#N Chemical compound C(N)(O)=O.C(C)#N QLLOYLKVIMXSDM-UHFFFAOYSA-N 0.000 description 2
- -1 calcium ions Chemical compound 0.000 description 2
- 239000013522 chelant Substances 0.000 description 2
- 230000000536 complexating effect Effects 0.000 description 2
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000003556 assay Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000003926 complexometric titration Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000010829 isocratic elution Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- AMMWFYKTZVIRFN-UHFFFAOYSA-N sodium 3-hydroxy-4-[(1-hydroxynaphthalen-2-yl)diazenyl]-7-nitronaphthalene-1-sulfonic acid Chemical compound [Na+].C1=CC=CC2=C(O)C(N=NC3=C4C=CC(=CC4=C(C=C3O)S(O)(=O)=O)[N+]([O-])=O)=CC=C21 AMMWFYKTZVIRFN-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The invention discloses a green preparation method of methyl cyanamide based, which belongs to the technical field of medicine synthesis and comprises the following steps: lime nitrogen is added into water, stirred, fully reacted and filtered; obtaining a cyanamide solution, adding liquid alkali into the cyanamide solution, dropwise adding methyl chloroformate, fully reacting, centrifuging to obtain a filtrate methyl cyanamide mixed solution, adding an EDTA water solution into the methyl cyanamide mixed solution, centrifuging to obtain a filtrate, and electrodialysis the filtrate to obtain methyl cyanamide. The invention reduces impurity calcium ion, sodium ion and chloride ion in methyl cyanurate by EDTA complexation and electrodialysis, improves the purity of methyl cyanurate, and circularly utilizes EDTA aqueous solution, liquid alkali and other materials, belonging to green production technology.
Description
Technical Field
The invention belongs to the technical field of medicine synthesis, and particularly relates to a green preparation method of methyl cyanamide based on cyanamide.
Background
Methyl cyanurate, a colorless or slightly pale blue aqueous solution, is weakly alkaline and has stink smell, and is an intermediate of various fine chemicals. In the prior art, most synthesis methods using cyanamide and methyl chloroformate as raw materials are used, but the method has the problems of low production efficiency, many side reactions, various impurities generated in the production process, difficult removal of the impurities, high raw material consumption and the like.
One-time hydrolysis process of lime nitrogen is disclosed in patent publication No. CN 104961655A. The method comprises the following specific steps: firstly, lime nitrogen is added into a hydrolysis reaction kettle, meanwhile, mixed gas containing nitrogen and carbon dioxide is continuously introduced into the hydrolysis reaction kettle, and then, the mass ratio of the lime nitrogen to the carbon dioxide is 1-2: 1, and methanol solution with the concentration of 5-15%, wherein the pH value in the kettle is 6.5-6.8, stirring continuously, keeping the temperature at 5-25 ℃, transferring the reacted material into a methyl-drop reaction kettle, wherein the pH value in the kettle is 7.4-7.8, dropwise adding methyl chloroformate into the methyl-drop reaction kettle, and stirring continuously to obtain the methyl-cyanocarbamate solution. The technology still has some defects, such as low production efficiency of methyl cyanurate, complex impurity components, difficult removal, incapability of recycling nitrogen, carbon dioxide and methanol solution, high raw material consumption and high production cost, and does not meet the requirements of green production. Therefore, a synthetic process is needed, which has strong impurity removal capability, and the reagent used for removing the impurities can be recycled, so that high-purity methyl cyanurate can be prepared.
Disclosure of Invention
The invention aims to provide a green preparation method of methyl cyanamide based on cyanamide, which aims to solve the problem that impurities are difficult to remove when methyl cyanamide is prepared based on cyanamide.
The aim of the invention can be achieved by the following technical scheme:
The green preparation method of the cyanamide-based methyl cyanamide comprises the following steps:
Slowly adding lime nitrogen into water, introducing CO 2, stirring, fully reacting, and filtering to obtain a cyanamide solution
And secondly, adding NaOH aqueous solution into the cyanamide solution, controlling the pH value in the reaction range of 9-11, dropwise adding methyl chloroformate into the cyanamide, continuously stirring, and fully reacting to obtain the methyl cyanamide mixed solution.
Thirdly, adding EDTA water solution into the methyl cyanocarbamate mixed solution, and centrifugally separating to obtain first filtrate and first filter residues.
And fourthly, electrodialysis is carried out on the first filtrate to obtain NaOH aqueous solution, HCl aqueous solution and methyl cyanurate.
Preferably, before lime nitrogen is added in the first step, water is preheated to the temperature of 25-30 ℃, and the temperature is controlled to be 35+/-3 ℃ when the lime nitrogen reacts with the water. The purpose is to promote the rate of formation of dicyandiamide and to suppress the generation of a polymer such as dicyandiamide.
Preferably, in the first step, the mass ratio of lime nitrogen to water is 1:2.5-3, and the reaction time is 1-2 h. The aim is to hydrolyze lime nitrogen sufficiently to increase the yield of cyanamide.
Preferably, the ratio of the molar amount of methyl chloroformate to the molar amount of the cyanamide in the cyanamide solution in the second step is 1.01-1.05:1. The method aims to improve the reaction rate, fully react cyanamide with methyl chloroformate, increase the yield of methyl cyanamide, and inhibit the occurrence of side reaction of the methyl chloroformate.
Preferably, in the second step, the reaction temperature of the cyanamide and the methyl chloroformate is controlled to be 45-50 ℃ and the reaction time is controlled to be 1-1.5 h. The method aims to fully react cyanamide with methyl chloroformate and improve the yield of the methyl cyanamide.
Preferably, the concentration of the EDTA aqueous solution in the third step is 0.5g/L, and the mass ratio of the EDTA aqueous solution to the cyanamide in the second step is 1:18-20. Aims to fully complex calcium ions in the methyl cyanocarbamate mixed solution and improve the purity of the methyl cyanocarbamate.
Preferably, in the fourth step, the electrodialysis is bipolar membrane electrodialysis. The aim is to remove sodium ions and chloride ions in the methyl cyanurate mixed solution and simultaneously generate a recyclable NaOH aqueous solution and a recyclable HCl aqueous solution.
Preferably, the first filter residue is processed in the following manner: adding HCl aqueous solution into the first filter residue, heating, and filtering to obtain second filtrate and second filter residue; adding water into the second filter residue, and filtering to obtain a third filter residue and EDTA water solution.
Preferably, an aqueous solution of HCl is added to the first filter residue, the pH is adjusted to 3 to 4, and the heating temperature is 80±5 ℃. The purpose is to destroy the complex structure of EDTA and calcium ions and reduce the complex structure to EDTA.
Preferably, the aqueous solution of EDTA and the aqueous solution of NaOH and the aqueous solution of HCl in the fourth step are recycled. Aims at saving the production cost and implementing the green production concept.
The invention has the beneficial effects that:
The invention adopts a lime nitrogen method to prepare cyanamide, dropwise adds methyl chloroformate to prepare methyl cyanamide, EDTA is complexed, and bipolar membrane electrodialysis impurity removal method is adopted to prepare high-purity methyl cyanamide. And adding EDTA aqueous solution, complexing calcium ions in the methyl cyanocarbamate to form chelate, reducing the concentration of the calcium ions, and recycling EDTA in a mode of adjusting pH, heating and adding water for dissolution. Bipolar membrane electrodialysis, reducing the concentration of sodium ions and chloride ions in methyl cyanide, generating NaOH and HCl, and respectively putting into methyl cyanide synthesis procedure and EDTA recovery procedure for recycling. Compared with the prior art, the invention uses EDTA complexation technology and bipolar membrane electrodialysis technology in the purification stage of methyl cyanurate to remove calcium ions, sodium ions and chloride ions in the solution, reduce the impurity concentration in the solution and improve the purity of methyl cyanurate. On the other hand, byproducts of bipolar membrane electrodialysis, namely NaOH and HCl, can be respectively used for a methyl cyanide carbamate synthesis process and an EDTA recovery process, and chelate of EDTA and calcium ions is subjected to pH adjustment by HCl, heating and water dissolution treatment to obtain an EDTA aqueous solution which can be used for complexing calcium ions in methyl cyanide carbamate.
When the method is used for preparing the methyl cyanurate based on the cyanamide, impurities such as calcium ions, sodium ions and chloride ions in the solution are effectively removed, the purity of the methyl cyanurate is improved, and the products of side reactions during impurity removal are fully utilized to recycle the methyl cyanurate. And finally, the discharged waste liquid is calcium salt solution, and the waste residue is insoluble substances in lime nitrogen waste residue, so that the component quantity of the waste liquid and the waste residue is reduced, and the treatment difficulty of the subsequent waste water and the waste residue is reduced.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a flow chart of the preparation of methyl cyanurate based on cyanamide according to the invention;
FIG. 2is a schematic representation of the operation of bipolar membrane electrodialysis used in the present invention;
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
The embodiment provides a method for synthesizing methyl cyanocarbamate by taking cyanamide and methyl chloroformate as raw materials and performing EDTA complexation and bipolar membrane electrodialysis impurity removal, which comprises the following steps:
Slowly adding 120kg of lime nitrogen into 330kg of water preheated to 25-30 ℃, wherein the effective nitrogen content in the lime nitrogen is 25%, stirring, controlling the temperature to be 32-38 ℃, reacting for 1h, and filtering to obtain a cyanamide solution, wherein the concentration of cyanamide is 30%, and the mass content of cyanamide in the cyanamide solution is 45kg according to 37.5% of theoretical yield.
And (3) dropwise adding 102.21kg of methyl chloroformate into the cyanamide filtrate, controlling the dropwise adding rate, adding liquid alkali into the cyanamide filtrate after 1-2 h, controlling the pH value in the reaction range between 9 and 11, controlling the temperature between 45 and 50 ℃, preserving heat and stirring after the dropwise adding is finished, fully reacting for 1h, and performing centrifugal separation to obtain the methyl cyanamide mixed solution.
Adding 2.37kgEDTA aqueous solution into the methyl cyanurate mixed solution, wherein the concentration of EDTA is 0.5h/L, and performing centrifugal separation to obtain first filtrate and first filter residue.
And carrying out bipolar membrane electrodialysis on the first filtrate, wherein the working structure of the bipolar membrane electrodialysis is shown in figure 2, and obtaining NaOH aqueous solution, HCl aqueous solution and methyl cyanurate.
Adding HCl aqueous solution into the first filter residue, heating, and filtering to obtain second filtrate and second filter residue; adding water into the second filter residue, and filtering to obtain a third filter residue and EDTA water solution.
Example 2
The embodiment provides a method for synthesizing methyl cyanocarbamate by taking cyanamide and methyl chloroformate as raw materials and performing EDTA complexation and bipolar membrane electrodialysis impurity removal, which comprises the following steps:
160kg of lime nitrogen with the effective nitrogen content of 25% is slowly added into 440kg of water with the preheating temperature of 25-30 ℃, stirring is carried out, the temperature is controlled at 32-38 ℃, the reaction is carried out for 1h, and then filtration is carried out, so as to obtain a cyanamide solution, wherein the concentration of cyanamide is 30%, and the mass is calculated according to 37.5% of theoretical yield, and the cyanamide content in the cyanamide solution is 60kg.
And (3) dropwise adding 136.28kg of methyl chloroformate into the cyanamide filtrate, controlling the dropwise adding rate, adding liquid alkali into the cyanamide filtrate after 1-2 h, controlling the pH value in the reaction range between 9 and 11, controlling the temperature between 45 and 50 ℃, preserving heat and stirring after the dropwise adding is finished, fully reacting for 1h, and performing centrifugal separation to obtain the methyl cyanamide mixed solution.
Adding 3.16kgEDTA aqueous solution into the methyl cyanurate mixed solution, wherein the concentration of EDTA is 0.5h/L, and performing centrifugal separation to obtain first filtrate and first filter residue.
And carrying out bipolar membrane electrodialysis on the first filtrate, wherein the working structure of the bipolar membrane electrodialysis is shown in figure 2, and obtaining NaOH aqueous solution, HCl aqueous solution and methyl cyanurate.
Adding HCl aqueous solution into the first filter residue, heating, and filtering to obtain second filtrate and second filter residue; adding water into the second filter residue, and filtering to obtain a third filter residue and EDTA water solution.
Example 3
The embodiment provides a method for synthesizing methyl cyanocarbamate by taking cyanamide and methyl chloroformate as raw materials and performing EDTA complexation and bipolar membrane electrodialysis impurity removal, which comprises the following steps:
Slowly adding 200kg of lime nitrogen into 550kg of water preheated to 25-30 ℃, wherein the effective nitrogen content in the lime nitrogen is 25%, stirring, controlling the temperature to be 32-38 ℃, reacting for 1h, and filtering to obtain a cyanamide solution, wherein the concentration of cyanamide is 30%, and the mass content of cyanamide in the cyanamide solution is 75kg according to 37.5% of theoretical yield.
And (3) dropwise adding 170.36kg of methyl chloroformate into the cyanamide filtrate, controlling the dropwise adding rate, adding liquid alkali into the cyanamide filtrate after 1-2 h, controlling the pH value in the reaction range between 9 and 11, controlling the temperature between 45 and 50 ℃, preserving heat and stirring after the dropwise adding is finished, fully reacting for 1h, and performing centrifugal separation to obtain the methyl cyanamide mixed solution.
Adding 3.95kgEDTA aqueous solution into the methyl cyanurate mixed solution, wherein the concentration of EDTA is 0.5h/L, and performing centrifugal separation to obtain first filtrate and first filter residue.
And carrying out bipolar membrane electrodialysis on the first filtrate, wherein the working structure of the bipolar membrane electrodialysis is shown in figure 2, and obtaining NaOH aqueous solution, HCl aqueous solution and methyl cyanurate.
Adding HCl aqueous solution into the first filter residue, heating, and filtering to obtain second filtrate and second filter residue; adding water into the second filter residue, and filtering to obtain a third filter residue and EDTA water solution.
Comparative example 1
In this comparative example, no EDTA was added as compared with example 2, comprising the steps of:
Slowly adding 120kg of lime nitrogen into 330kg of water preheated to 25-30 ℃, wherein the effective nitrogen content in the lime nitrogen is 25%, stirring, controlling the temperature to be 32-38 ℃, reacting for 1h, and filtering to obtain a cyanamide solution, wherein the concentration of cyanamide is 30%, and the mass content of cyanamide in the cyanamide solution is 45kg according to 37.5% of theoretical yield.
And (3) dropwise adding 102.21kg of methyl chloroformate into the cyanamide filtrate, controlling the dropwise adding rate, adding liquid alkali into the cyanamide filtrate after 1-2 h, controlling the pH value in the reaction range between 9 and 11, controlling the temperature between 45 and 50 ℃, preserving heat and stirring after the dropwise adding is finished, fully reacting for 1h, and performing centrifugal separation to obtain the methyl cyanamide mixed solution.
And (3) carrying out bipolar membrane electrodialysis on the methyl cyanurate mixed solution, wherein the working structure of the bipolar membrane electrodialysis is shown in figure 2, and obtaining NaOH aqueous solution, HCl aqueous solution and methyl cyanurate.
Comparative example 2
In this comparative example, compared to example 2, bipolar membrane electrodialysis was not performed, comprising the steps of:
160kg of lime nitrogen with the effective nitrogen content of 25% is slowly added into 440kg of water with the preheating temperature of 25-30 ℃, stirring is carried out, the temperature is controlled at 32-38 ℃, the reaction is carried out for 1h, and then filtration is carried out, so as to obtain a cyanamide solution, wherein the concentration of cyanamide is 30%, and the mass is calculated according to 37.5% of theoretical yield, and the cyanamide content in the cyanamide solution is 60kg.
And (3) dropwise adding 136.28kg of methyl chloroformate into the cyanamide filtrate, controlling the dropwise adding rate, adding liquid alkali into the cyanamide filtrate after 1-2 h, controlling the pH value in the reaction range between 9 and 11, controlling the temperature between 45 and 50 ℃, preserving heat and stirring after the dropwise adding is finished, fully reacting for 1h, and performing centrifugal separation to obtain the methyl cyanamide mixed solution.
Adding 3.16kgEDTA aqueous solution into the methyl cyanurate mixed solution, wherein the concentration of EDTA is 0.5h/L, and performing centrifugal separation to obtain methyl cyanurate and first filter residue.
Adding HCl aqueous solution into the first filter residue, heating, and filtering to obtain second filtrate and second filter residue; adding water into the second filter residue, and filtering to obtain a third filter residue and EDTA water solution.
Comparative example 3
In this comparative example, in comparison with example 2, no EDTA was added and no bipolar membrane electrodialysis was performed, comprising the steps of:
160kg of lime nitrogen with the effective nitrogen content of 25% is slowly added into 440kg of water with the preheating temperature of 25-30 ℃, stirring is carried out, the temperature is controlled at 32-38 ℃, the reaction is carried out for 1h, and then filtration is carried out, so as to obtain a cyanamide solution, wherein the concentration of cyanamide is 30%, and the mass is calculated according to 37.5% of theoretical yield, and the cyanamide content in the cyanamide solution is 60kg.
And (3) dropwise adding 136.28kg of methyl chloroformate into the cyanamide filtrate, controlling the dropwise adding rate, adding liquid alkali into the cyanamide filtrate after 1-2 h, controlling the pH value in the reaction range between 9 and 11, controlling the temperature between 45 and 50 ℃, preserving heat and stirring after the dropwise adding is finished, fully reacting for 1h, and centrifuging to obtain the methyl cyanamide.
Taking methyl cyanocarbamate mixed solution, measuring the concentration of calcium ions, sodium ions and chloride ions in the mixed solution, and taking methyl cyanocarbamate, and measuring the purity, the concentration of calcium ions, sodium ions and chloride ions of the methyl cyanocarbamate.
Note that: the method for measuring the purity of the methyl cyanocarbamate comprises the following steps: the chromatographic-ultraviolet detector assay is performed under the following conditions: the method comprises the steps of adopting an HI-IL-IC hydrophilic chromatographic column, taking methanol-10 mmol/L disodium hydrogen phosphate solution (volume ratio is 5:95, pH value is regulated by perchloric acid to 3.0) as a mobile phase, performing isocratic elution, and detecting the wavelength of 210nm, wherein the flow rate is 0.8 mL/min.
The method for measuring the concentration of calcium ions comprises the following steps: the specific conditions of the complexometric titration method are as follows: EBT (chrome black T) is used as an indicator, EDTA (ethylenediamine tetraacetic acid) is used as a titrant, and the change of the solution from red to blue is used as a titration endpoint.
The method for measuring the sodium ion concentration comprises the following steps: direct measurement was performed using a sodium ion analyzer.
The method for measuring the concentration of chloride ions comprises the following steps: and directly measuring by using a portable chloride ion content tester.
Performance tests were performed on examples 1-3 and comparative examples 1-3, and the results are shown in table 1:
TABLE 1
As can be seen from table 1, in the process of preparing methyl cyanurate based on cyanamide, EDTA complexation and bipolar membrane electrodialysis are used to remove impurities, the purity of methyl cyanurate is improved, and the concentration of calcium ions, sodium ions and chloride ions is greatly reduced. In combination with example 2 and comparative example 3, the purity of methyl cyanocarbamate increased by 2.43% after removal of impurities by EDTA complexation and bipolar membrane electrodialysis, the sodium ion concentration in example 2 was 0.56% of the calcium ion concentration in comparative example 1, the sodium ion concentration in example 2 was 1.93% of the calcium ion concentration in comparative example 1, and the chloride ion concentration in example 2 was 0.89% of the chloride ion concentration in comparative example 1.
As can be seen from examples 1-3, the purity of methyl cyanocarbamate is improved by EDTA complexation and bipolar membrane electrodialysis when the mass of lime nitrogen is 120-200 kg, wherein the removal rates of calcium ions, sodium ions and chloride ions are kept stable.
As can be seen from example 2 and comparative example 1, in the process of preparing methyl cyanamide based on cyanamide, bipolar membrane electrodialysis can remove calcium ions in methyl cyanamide, but has poor effect, EDTA complexation can effectively remove calcium ions in methyl cyanamide, and the removal rate of calcium ions reaches 94.49% by combining EDTA complexation and bipolar membrane electrodialysis.
As can be seen from example 2 and comparative example 2, bipolar membrane electrodialysis can remove sodium ions and chloride ions from methyl cyanide in the process of preparing methyl cyanide based on cyanamide, and the removal rates reach 98.11% and 99.12%, respectively.
In conclusion, the invention effectively removes the impurity calcium ions, sodium ions and chloride ions in the methyl cyanurate, improves the purity of the methyl cyanurate, recycles EDTA, naOH aqueous solution and HCl aqueous solution, and is a green production process.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (9)
1. The green preparation method of the cyanamide-based methyl cyanamide is characterized by comprising the following steps of:
Slowly adding lime nitrogen into water, introducing CO 2, stirring, and filtering after the lime nitrogen fully reacts to obtain a cyanamide solution;
Secondly, adding NaOH aqueous solution into the cyanamide solution, controlling the pH value in the range of 9-11 during the reaction, dropwise adding methyl chloroformate into the cyanamide, continuously stirring, and fully reacting to obtain methyl cyanamide mixed solution;
Thirdly, adding EDTA water solution into the methyl cyanocarbamate mixed solution, and centrifugally separating to obtain first filtrate and first filter residues;
And fourthly, electrodialysis is carried out on the first filtrate to obtain NaOH aqueous solution, HCl aqueous solution and methyl cyanurate.
2. The green preparation method of cyanamide based methyl cyanamide according to claim 1, wherein the water is preheated to 25-30 ℃ before lime nitrogen is added in the first step, and the temperature is controlled to 35+/-3 ℃ when the lime nitrogen reacts with the water.
3. The green preparation method of cyanamide based methyl cyanamide according to claim 1, wherein in the first step, the mass ratio of lime nitrogen to water is 1:2.5-3, and the reaction time is 1-2 h.
4. The green process for the preparation of melamine based methyl cyanamide according to claim 1, characterized in that the ratio of the molar amount of methyl chloroformate to the molar amount of melamine in the solution of melamine in the second step is 1.01-1.05:1.
5. The green preparation method of the cyanamide-based methyl carbamate according to claim 1, wherein the reaction temperature of the cyanamide and the methyl chloroformate is controlled to be 45-50 ℃ and the reaction time is controlled to be 1-1.5 h.
6. The green preparation method of cyanamide based methyl cyanamide according to claim 1, wherein the concentration of the EDTA aqueous solution in the third step is 0.5g/L, and the mass ratio of the EDTA aqueous solution to the cyanamide in the second step is 1:18-20.
7. The green process for the preparation of melamine based methyl cyanurate according to claim 1, wherein the aqueous NaOH and aqueous HCl solutions of the fourth step are recycled.
8. The green preparation method of the cyanamide-based methyl cyanamide according to claim 1, is characterized in that an HCl aqueous solution is added into the first filter residue, and the mixture is heated and filtered to obtain a second filtrate and a second filter residue; adding water into the second filter residue, and filtering to obtain a third filter residue and EDTA water solution.
9. The green preparation method of cyanamide based methyl cyanamide according to claim 8, is characterized in that the aqueous solution of HCl is added into the first filter residue, the pH is regulated to 3-4, and the heating temperature is 80+/-5 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410562172.1A CN118307445A (en) | 2024-05-08 | 2024-05-08 | Green preparation method of cyanamide-based methyl carbamate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410562172.1A CN118307445A (en) | 2024-05-08 | 2024-05-08 | Green preparation method of cyanamide-based methyl carbamate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118307445A true CN118307445A (en) | 2024-07-09 |
Family
ID=91726247
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410562172.1A Pending CN118307445A (en) | 2024-05-08 | 2024-05-08 | Green preparation method of cyanamide-based methyl carbamate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118307445A (en) |
-
2024
- 2024-05-08 CN CN202410562172.1A patent/CN118307445A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1962611B (en) | Process for preparing glycine using hydroxy-acetonitrile method | |
| EP2370586A2 (en) | Process for the preparation of a monovalent succinate salt | |
| CN111004162B (en) | Method and device for preparing L-selenocysteine by using sodium triacetoxyborohydride as reducing agent | |
| US4045340A (en) | Method for recovering and exploiting waste of the chromic anhydride production | |
| CN106588681B (en) | A kind of method that L alanine is prepared using hydroxyproline waste water as raw material | |
| CN118307445A (en) | Green preparation method of cyanamide-based methyl carbamate | |
| CN111004131A (en) | Method for recovering sucralose by-product salt | |
| CN113816406B (en) | Environment-friendly hydrotalcite synthesis process | |
| CN112897600B (en) | Preparation method of tetraamminepalladium sulfate (II) | |
| CN111018744B (en) | Method for synthesizing acetamidine, acetamidine and application thereof, and vitamin B1 | |
| CN113699209A (en) | 7-ADCA recovery method | |
| CN106673015B (en) | The method for producing high-purity ammonium fluoride using sodium bifluoride waste residue | |
| CN111484039A (en) | Method for removing sodium/potassium carbonate and sodium/potassium hydroxide in sodium cyanide/potassium solution | |
| CN111302963A (en) | Method for preparing 3-aminomethyl-5-methylhexanoic acid | |
| CN115872882B (en) | Synthesis method of 3-chloro-alanine | |
| CN118324663A (en) | Efficient synthesis process for preparing methyl cyanamide from cyanamide | |
| CN115650322B (en) | Method for nitrosyl ruthenium nitrate | |
| CN1079079C (en) | Process for preparing potassium ferrocyanide | |
| CN117986204B (en) | Synthesis method of dyclonine hydrochloride | |
| CN115504442B (en) | Preparation method of high-purity optical glass additive lithium phosphate | |
| CN114477249B (en) | Method for preparing high-purity magnesium hydroxide and calcium sulfate by adopting calcium carbide furnace purification ash | |
| CN114605336B (en) | Post-treatment and waste water resource utilization method for synthesizing 4, 6-dihydroxypyrimidine | |
| CN118184528A (en) | Preparation method of sarcosine | |
| CN104892436B (en) | Iminodiacetonitrile produces the recycling method and device of mother liquor | |
| CN116715254A (en) | Ammonium chloride auxiliary material and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination |