CN116082197A - Preparation method of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) - Google Patents
Preparation method of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) Download PDFInfo
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- CN116082197A CN116082197A CN202310126765.9A CN202310126765A CN116082197A CN 116082197 A CN116082197 A CN 116082197A CN 202310126765 A CN202310126765 A CN 202310126765A CN 116082197 A CN116082197 A CN 116082197A
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- VETHREXFBVHLJJ-UHFFFAOYSA-N 1-(dimethylamino)-3-[6-(dimethylaminocarbamoylamino)hexyl]urea Chemical compound CN(C)NC(=O)NCCCCCCNC(=O)NN(C)C VETHREXFBVHLJJ-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
- 239000005057 Hexamethylene diisocyanate Substances 0.000 claims abstract description 56
- RRAMGCGOFNQTLD-UHFFFAOYSA-N hexamethylene diisocyanate Chemical compound O=C=NCCCCCCN=C=O RRAMGCGOFNQTLD-UHFFFAOYSA-N 0.000 claims abstract description 56
- RHUYHJGZWVXEHW-UHFFFAOYSA-N 1,1-Dimethyhydrazine Chemical compound CN(C)N RHUYHJGZWVXEHW-UHFFFAOYSA-N 0.000 claims abstract description 51
- 238000000926 separation method Methods 0.000 claims abstract description 32
- 239000002904 solvent Substances 0.000 claims abstract description 32
- 238000001035 drying Methods 0.000 claims abstract description 26
- 239000007788 liquid Substances 0.000 claims abstract description 26
- 239000003495 polar organic solvent Substances 0.000 claims abstract description 26
- 238000007259 addition reaction Methods 0.000 claims abstract description 17
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000005935 nucleophilic addition reaction Methods 0.000 claims abstract description 10
- -1 alkyl cyanide Chemical compound 0.000 claims abstract description 9
- 150000008282 halocarbons Chemical class 0.000 claims abstract description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 19
- 238000003756 stirring Methods 0.000 claims description 18
- 238000001291 vacuum drying Methods 0.000 claims description 13
- SCYULBFZEHDVBN-UHFFFAOYSA-N 1,1-Dichloroethane Chemical group CC(Cl)Cl SCYULBFZEHDVBN-UHFFFAOYSA-N 0.000 claims description 11
- 238000007599 discharging Methods 0.000 claims description 11
- 238000002844 melting Methods 0.000 claims description 11
- 230000008018 melting Effects 0.000 claims description 11
- 238000004321 preservation Methods 0.000 claims description 9
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000004880 explosion Methods 0.000 abstract description 5
- 230000003068 static effect Effects 0.000 abstract description 5
- 230000005611 electricity Effects 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 150000001298 alcohols Chemical class 0.000 abstract description 2
- 238000003786 synthesis reaction Methods 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 description 39
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 24
- 239000000047 product Substances 0.000 description 9
- 239000000203 mixture Substances 0.000 description 8
- 238000005303 weighing Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 239000012295 chemical reaction liquid Substances 0.000 description 4
- 238000010892 electric spark Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000012265 solid product Substances 0.000 description 4
- 239000003849 aromatic solvent Substances 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 239000003112 inhibitor Substances 0.000 description 2
- 238000004383 yellowing Methods 0.000 description 2
- 229920002334 Spandex Polymers 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000007810 chemical reaction solvent Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004611 light stabiliser Substances 0.000 description 1
- 238000004811 liquid chromatography Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000004759 spandex Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C281/00—Derivatives of carbonic acid containing functional groups covered by groups C07C269/00 - C07C279/00 in which at least one nitrogen atom of these functional groups is further bound to another nitrogen atom not being part of a nitro or nitroso group
- C07C281/06—Compounds containing any of the groups, e.g. semicarbazides
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide). The preparation method provided by the invention comprises the following steps: respectively dissolving hexamethylene diisocyanate and unsymmetrical dimethylhydrazine in a polar organic solvent, wherein the polar organic solvent is independently an alcohol solvent, an alkyl cyanide solvent, a halogenated hydrocarbon solvent or an ether solvent; dropwise adding hexamethylene diisocyanate solution into the unsymmetrical dimethylhydrazine solution to carry out nucleophilic addition reaction; and (3) carrying out solid-liquid separation and drying to obtain the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide). According to the preparation method provided by the invention, alcohols, alkyl cyanides or halogenated hydrocarbon solvents are used, so that the explosion risk caused by static electricity when the addition reaction feed liquid is discharged is reduced, and the production safety coefficient is improved; meanwhile, the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) prepared by the preparation method provided by the invention is high in purity and low in chromaticity.
Description
Technical Field
The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide).
Background
The yellowing inhibitor 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) is a yellowing inhibitor for spandex fiber or synthetic resin, and a light stabilizer for polyamide resin, and is widely used in polyurethane industry.
At present, the preparation process of the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) comprises the following steps: and (3) dropwise adding toluene solution of hexamethylene diisocyanate into toluene solution of unsymmetrical dimethylhydrazine at the reaction temperature of between 10 and 25 ℃ to react, carrying out solid-liquid separation by using a centrifuge after the reaction is finished, and carrying out vacuum drying on wet materials by using a dryer.
The existing preparation technology for preparing 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) by adopting aromatic solvents (such as toluene) has the following main defects: toluene is poor in dispersibility when being used as a solvent, impurities are easily produced due to incomplete reaction, so that the purity of a product is reduced, and the purity of most products is not more than 98%; meanwhile, toluene is used as a solvent, and the static electrode is easy to cause explosion risk during discharging, so that a large safety risk exists; and the boiling point of toluene is higher, and the energy consumed in the product drying process is larger.
Disclosure of Invention
The invention aims to provide a preparation method of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide), and the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) prepared by the preparation method provided by the invention has high purity and low chromaticity, effectively reduces the explosion risk caused by static electricity, and has high production safety coefficient.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide), which comprises the following steps:
respectively dissolving hexamethylene diisocyanate and unsymmetrical dimethylhydrazine in a polar organic solvent to respectively obtain a hexamethylene diisocyanate solution and a unsymmetrical dimethylhydrazine solution; the polar organic solvent is independently an alcohol solvent, an alkyl cyanide solvent, a halogenated hydrocarbon solvent or an ether solvent;
dropwise adding the hexamethylene diisocyanate solution into the unsymmetrical dimethylhydrazine solution to carry out nucleophilic addition reaction to obtain addition reaction feed liquid;
and (3) after solid-liquid separation of the addition reaction feed liquid, collecting solid components and drying to obtain the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide).
Preferably, the polar organic solvent is dichloroethane or ethylene glycol dimethyl ether.
Preferably, the water content of the polar organic solvent is less than 0.1%, and the purity of the polar organic solvent is more than or equal to 98%.
Preferably, the molar ratio of the hexamethylene diisocyanate to the unsymmetrical dimethylhydrazine is 1 (2-2.1).
Preferably, in the hexamethylene diisocyanate solution, the mass ratio of the polar organic solvent to the hexamethylene diisocyanate is (3-4): 1.
Preferably, in the unsymmetrical dimethylhydrazine solution, the mass ratio of the polar organic solvent to the unsymmetrical dimethylhydrazine is (6-7): 1.
Preferably, the dropping speed is 5-10L/min; in the whole dropping process, the temperature of the unsymmetrical dimethylhydrazine solution is 0-30 ℃; the dropwise adding is carried out under the condition that the unsymmetrical dimethylhydrazine solution is stirred, and the stirring rotating speed is 45-75 r/min.
Preferably, after the dropping is completed, the method further includes: keeping the temperature and continuing the nucleophilic addition reaction; the temperature of the heat preservation is 0-30 ℃, and the time of the heat preservation is 1-1.5 h.
Preferably, the solid-liquid separation is centrifugal separation, and the working parameters of the centrifugal separation include:
the centrifugal separation time is 20-30 min; the feeding speed of the centrifugal separation is 600-750 rpm; the separation rotating speed of the centrifugal separation is 1400-1600 rpm, and the discharge rotating speed of the centrifugal separation is 100-200 rpm;
the drying is vacuum drying, the temperature of the vacuum drying is 80-85 ℃, the heat preservation time of the vacuum drying is 8-8.5 h, and the pressure of the vacuum drying is less than or equal to-0.085 MPa.
Preferably, the chromaticity of the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) is 1-30 black, the melting point temperature is 140-145 ℃, the volatility is less than or equal to 0.1%, and the purity is more than or equal to 99%.
The invention provides a preparation method of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide), which comprises the following steps: respectively dissolving hexamethylene diisocyanate and unsymmetrical dimethylhydrazine in a polar organic solvent to respectively obtain a hexamethylene diisocyanate solution and a unsymmetrical dimethylhydrazine solution; the polar organic solvent is independently an alcohol solvent, an alkyl cyanide solvent, a halogenated hydrocarbon solvent or an ether solvent; dropwise adding the hexamethylene diisocyanate solution into the unsymmetrical dimethylhydrazine solution to carry out nucleophilic addition reaction to obtain addition reaction feed liquid; and (3) after solid-liquid separation of the addition reaction feed liquid, collecting solid components and drying to obtain the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide). According to the preparation method provided by the invention, alcohol, alkyl cyanide or halogenated hydrocarbon solvents are used for replacing aromatic solvents in the existing method, so that the explosion risk caused by static electricity when the addition reaction feed liquid is discharged is reduced, and the production safety coefficient is improved; meanwhile, the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) prepared by the preparation method provided by the invention has high purity and low chromaticity, and compared with the method that toluene is used as a reaction solvent, the purity of the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) is improved by more than or equal to 99 percent from 965 to 97.5 percent, and the chromaticity is reduced to less than or equal to 20 black increase from more than 200 black (the product is yellow or white-like powder without obvious crystal form and the chromaticity is more than 200).
Drawings
FIG. 1 is a schematic diagram showing the structure of 1, 6-hexamethylene-bis (N, N-dimethylsemicarbazide) prepared in examples 1 to 3 according to the present invention;
FIG. 2 shows a high performance liquid chromatogram of 1, 6-hexamethylenebis (N, N-dimethylsemicarbazide) prepared in example 1 of the present invention.
Detailed Description
The invention provides a preparation method of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide), which comprises the following steps:
respectively dissolving hexamethylene diisocyanate and unsymmetrical dimethylhydrazine in a polar organic solvent to respectively obtain a hexamethylene diisocyanate solution and a unsymmetrical dimethylhydrazine solution; the polar organic solvent is independently an alcohol solvent, an alkyl cyanide solvent, a halogenated hydrocarbon solvent or an ether solvent;
dropwise adding the hexamethylene diisocyanate solution into the unsymmetrical dimethylhydrazine solution to carry out nucleophilic addition reaction to obtain addition reaction feed liquid;
and (3) after solid-liquid separation of the addition reaction feed liquid, collecting solid components and drying to obtain the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide).
In the present invention, all preparation materials/components are commercially available products well known to those skilled in the art unless specified otherwise.
Respectively dissolving hexamethylene diisocyanate and unsymmetrical dimethylhydrazine in a polar organic solvent to respectively obtain a hexamethylene diisocyanate solution and a unsymmetrical dimethylhydrazine solution; the polar organic solvent is independently an alcohol solvent, an alkyl cyanide solvent or a halogenated hydrocarbon solvent.
In the invention, the mass percentage of the unsymmetrical dimethylhydrazine is preferably more than or equal to 99 percent.
In the present invention, the polar organic solvent is particularly preferably dichloroethane or ethylene glycol dimethyl ether, more preferably dichloroethane.
In the present invention, the water content of the polar organic solvent is preferably < 0.1%, and the purity of the polar organic solvent is preferably not less than 98%.
In the present invention, the molar ratio of the hexamethylene diisocyanate to the unsymmetrical dimethylhydrazine is preferably 1 (2 to 2.1).
In the present invention, the mass ratio of the polar organic solvent to the hexamethylene diisocyanate in the hexamethylene diisocyanate solution is preferably (3 to 4): 1, more preferably (3.2 to 3.7): 1.
In the present invention, the mass ratio of the polar organic solvent to the unsymmetrical dimethylhydrazine in the unsymmetrical dimethylhydrazine solution is preferably (6 to 7): 1, more preferably (6.2 to 6.5): 1.
In the present invention, the dissolution is preferably performed under stirring, and the stirring time is preferably 30 minutes.
After the hexamethylene diisocyanate solution and the unsymmetrical dimethylhydrazine solution are obtained, the hexamethylene diisocyanate solution is dripped into the unsymmetrical dimethylhydrazine solution to carry out nucleophilic addition reaction, so as to obtain addition reaction feed liquid.
In the present invention, the dropping speed is preferably 5 to 10L/min, more preferably 5.5 to 8L/min.
In the present invention, the temperature of the unsymmetrical dimethylhydrazine solution is preferably 0 to 30℃and more preferably 5 to 30℃during the whole process of the dropping.
In the present invention, the whole process of the dropping is performed under the condition that the unsymmetrical dimethylhydrazine solution is stirred, and the stirring rotation speed is preferably 45 to 75r/min, more preferably 50 to 65r/min.
In the present invention, after the completion of the dropping, the present invention preferably further includes: keeping the temperature and continuing the nucleophilic addition reaction; the temperature of the heat preservation is preferably 0-30 ℃, more preferably 5-30 ℃; the time for the heat preservation is preferably 1 to 1.5 hours, more preferably 1.5 hours.
In the present invention, the nucleophilic addition reaction is preferably carried out in a closed reactor containing stirring means.
After the addition reaction feed liquid is obtained, the solid-liquid separation is carried out on the addition reaction feed liquid, and then solid components are collected and dried to obtain the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide).
In the present invention, the solid-liquid separation is a centrifugal separation, and the operating parameters of the centrifugal separation preferably include: the time of the centrifugal separation is preferably 20 to 30min, more preferably 22 to 26min; the feed rate of the centrifugal separation is preferably 600 to 750 rpm, more preferably 650 to 700 rpm; the separation rotation speed of the centrifugal separation is preferably 1400-1600 rpm, more preferably 1450-1550 rpm; the discharge speed of the centrifugal separation is preferably 100 to 200 rpm, more preferably 125 to 185 rpm.
In the present invention, the centrifugal separation is preferably performed in a centrifuge.
In the present invention, the drying is preferably vacuum drying, and the temperature of the vacuum drying is 80-85 ℃, more preferably 80 ℃; the heat preservation time of the vacuum drying is 8-8.5 h, more preferably 8h; the pressure of the vacuum drying is preferably less than or equal to-0.085 MPa.
In the present invention, the drying is preferably performed in a rake vacuum dryer.
In the present invention, the 1, 6-hexamethylene-bis (N, N-dimethylsemicarbazide) preferably has a chromaticity of 1 to 30 Heiden, a melting point temperature of 140 to 145 ℃, a volatility of preferably not more than 0.1% and a purity of preferably not less than 99%.
According to the preparation method provided by the invention, alcohols, alkyl cyanides or halogenated hydrocarbon solvents are used, and various operation parameters of the affinity addition reaction are regulated and controlled, so that the chromaticity of 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) is preferably 1-30 Hemsl, the melting point temperature is preferably 140-145 ℃, the volatility is preferably less than or equal to 0.1%, the mass percentage content is preferably more than or equal to 99% and the crystallinity is high on the basis of reducing the explosion risk of addition reaction feed liquid caused by static electricity during discharging and improving the production safety coefficient.
The technical solutions provided by the present invention are described in detail below with reference to the drawings and examples for further illustrating the present invention, but they should not be construed as limiting the scope of the present invention.
Example 1
Accurately weighing 700kg of hexamethylene diisocyanate, adding the hexamethylene diisocyanate into a 6000L No. 1 reaction kettle, adding 2200L of dichloroethane into the No. 1 reaction kettle, and stirring for 30 minutes at regular time to fully mix the hexamethylene diisocyanate to prepare a hexamethylene diisocyanate solution;
accurately weighing 510kg of unsymmetrical dimethylhydrazine (the mass percentage content is more than or equal to 99%), adding the unsymmetrical dimethylhydrazine into a 6000L2 reaction kettle, adding 3100L dichloroethane into the 2 reaction kettle, and stirring for 30 minutes at regular time to fully mix the unsymmetrical dimethylhydrazine and the solvent solution;
and (3) dropwise adding the hexamethylene diisocyanate solution in the reaction kettle 1 into the reaction kettle 2, and mixing with the unsymmetrical dimethylhydrazine solution to perform an addition reaction. The dripping speed is controlled to be 10L/min in the whole dripping process, the temperature of a No. 2 reaction kettle is maintained at 30 ℃, and the stirring speed is maintained at 75 revolutions per minute until all hexamethylene diisocyanate solution is completely dripped;
after the dripping of the hexamethylene diisocyanate solution is finished, keeping the temperature at 30 ℃ for 1.5 hours at a timing, and continuing the reaction to obtain a reaction solution;
centrifugally discharging the reaction liquid by using a centrifugal machine, wherein the spin-drying time of the centrifugal machine is 30min;
drying the obtained solid product by a rake vacuum dryer under the condition that the pressure is less than or equal to-0.085 MPa, setting the drying temperature to 80 ℃ and the drying time to 8 hours, and obtaining 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide);
the indexes of the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) product are detected, including appearance, chromaticity, melting point, volatility and content.
The 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) prepared in the example has the appearance of white crystals, chromaticity of 20 black-former, melting point of 141-145 ℃, volatility of 0.06% and purity of 99.94%, and is discharged centrifugally, can be observed visually through a centrifuge mirror, and no electric spark is generated during discharging materials.
FIG. 1 is a high performance liquid chromatogram of 1, 6-hexamethylene-bis (N, N-dimethylsemicarbazide) prepared in example 1 of the present invention, wherein the peak-emitting results of FIG. 1 are shown in Table 1.
Table 1 liquid chromatography detection data
| Sequence number | Retention time | Peak width | Peak area | Height | |
| 1 | 2.778 | 1.43 | 7902.47 | 789.24 | 99.94 |
| 2 | 4.805 | 0.09 | 0.51 | 0.09 | 0.01 |
| 3 | 5.673 | 0.32 | 3.25 | 0.12 | 0.04 |
| 4 | 9.557 | 0.21 | 1.11 | 0.06 | 0.01 |
Example 2
Accurately weighing 700kg of hexamethylene diisocyanate, adding the hexamethylene diisocyanate into a 6000L No. 1 reaction kettle, adding 2200L of dichloroethane into the No. 1 reaction kettle, and stirring for 30 minutes at regular time to fully mix the hexamethylene diisocyanate to prepare a hexamethylene diisocyanate solution;
accurately weighing 510kg of unsymmetrical dimethylhydrazine (the mass percentage content is more than or equal to 99%), adding the unsymmetrical dimethylhydrazine into a 6000L2 reaction kettle, adding 3100L dichloroethane into the 2 reaction kettle, and stirring for 30 minutes at regular time to fully mix the unsymmetrical dimethylhydrazine and the solvent solution;
and (3) dropwise adding the hexamethylene diisocyanate solution in the reaction kettle 1 into the reaction kettle 2, and mixing with the unsymmetrical dimethylhydrazine solution to react. The dripping speed is controlled to be 5L/min in the whole dripping process, the temperature of a No. 2 reaction kettle is maintained at 5 ℃, and the stirring speed is kept at 45 revolutions per minute until all hexamethylene diisocyanate solution is completely dripped;
after the dripping of the hexamethylene diisocyanate solution is finished, keeping the temperature at 5 ℃ for 1.5 hours at a timing, and continuing the reaction to obtain a reaction solution;
centrifugally discharging the reaction liquid by using a centrifugal machine, wherein the spin-drying time of the centrifugal machine is 20min;
drying the obtained solid product by a rake vacuum dryer under the condition that the pressure is less than or equal to-0.085 MPa, setting the drying temperature to 80 ℃ and the drying time to 8 hours, and obtaining 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide);
the indexes of the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) product are detected, including appearance, chromaticity, melting point, volatility and content.
The 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) prepared in the example has the appearance of white crystals, chromaticity of 18 Heiden, melting point of 140-144 ℃, volatility of 0.07% and purity of 99.1%, and is discharged centrifugally, can be observed visually through a centrifuge mirror, and no electric spark is generated during discharging materials.
Example 3
Accurately weighing 700kg of hexamethylene diisocyanate, adding the hexamethylene diisocyanate into a 6000L No. 1 reaction kettle, adding 2200L of dichloroethane into the No. 1 reaction kettle, and stirring for 30 minutes at regular time to fully mix the hexamethylene diisocyanate to prepare a hexamethylene diisocyanate solution;
accurately weighing 510kg of unsymmetrical dimethylhydrazine (the mass percentage content is more than or equal to 99%), adding the unsymmetrical dimethylhydrazine into a 6000L2 reaction kettle, adding 3100L dichloroethane into the 2 reaction kettle, and stirring for 30 minutes at regular time to fully mix the unsymmetrical dimethylhydrazine and the solvent solution;
and (3) dropwise adding the hexamethylene diisocyanate solution in the reaction kettle 1 into the reaction kettle 2, and mixing with the unsymmetrical dimethylhydrazine solution to react. The dripping speed is controlled to be 10L/min in the whole dripping process, the temperature of a No. 2 reaction kettle is maintained at 20 ℃, and the stirring speed is maintained at 75 revolutions per minute until all hexamethylene diisocyanate solution is completely dripped;
after the dripping of the hexamethylene diisocyanate solution is finished, keeping the temperature at 20 ℃ for 1.5 hours at a timing, and continuing the reaction to obtain a reaction solution;
centrifugally discharging the reaction liquid by using a centrifugal machine, wherein the spin-drying time of the centrifugal machine is 20min;
drying the obtained solid product by a rake vacuum dryer under the condition that the pressure is less than or equal to-0.085 MPa, setting the drying temperature to 80 ℃ and the drying time to 8 hours, and obtaining 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide);
the indexes of the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) product are detected, including appearance, chromaticity, melting point, volatility and content.
The 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) prepared in the example has the appearance of white crystals, chromaticity of 15 Heiden, melting point of 142-145 ℃, volatility of 0.03% and purity of 99.2%, and is discharged through centrifugation, can be visually observed through a centrifuge view mirror, and no electric spark is generated during discharging materials.
Comparative example 1
Accurately weighing 700kg of hexamethylene diisocyanate, adding the hexamethylene diisocyanate into a 6000L No. 1 reaction kettle, adding 2200L of toluene into the No. 1 reaction kettle, and stirring for 30 minutes at regular time to fully mix the hexamethylene diisocyanate to prepare a hexamethylene diisocyanate solution;
accurately weighing 510kg of unsymmetrical dimethylhydrazine (the mass percentage content is more than or equal to 99%), adding the unsymmetrical dimethylhydrazine into a 6000L2 reaction kettle, adding 3100L dichloroethane into the 2 reaction kettle, and stirring for 30 minutes at regular time to fully mix the unsymmetrical dimethylhydrazine and the solvent solution;
and (3) dropwise adding the hexamethylene diisocyanate solution in the reaction kettle 1 into the reaction kettle 2, and mixing with the unsymmetrical dimethylhydrazine solution to perform an addition reaction. The dripping speed is controlled to be 10L/min in the whole dripping process, the temperature of a No. 2 reaction kettle is maintained at 30 ℃, and the stirring speed is maintained at 75 revolutions per minute until all hexamethylene diisocyanate solution is completely dripped;
after the dripping of the hexamethylene diisocyanate solution is finished, keeping the temperature at 30 ℃ for 1.5 hours at a timing, and continuing the reaction to obtain a reaction solution;
centrifugally discharging the reaction liquid by using a centrifugal machine, wherein the spin-drying time of the centrifugal machine is 30min;
drying the obtained solid product by a rake vacuum dryer under the condition that the pressure is less than or equal to-0.085 MPa, setting the drying temperature to 80 ℃ and the drying time to 8 hours, and obtaining 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide);
the indexes of the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) product are detected, including appearance, chromaticity, melting point, volatility and content.
The 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide) prepared in the example has the appearance of white crystals, chromaticity of 217 black-former and purity of 97.26 percent, and is discharged through centrifugation, visual observation can be realized through a centrifuge sight glass, and a large amount of electric sparks are generated in a centrifuge during discharging the materials.
Although the foregoing embodiments have been described in some, but not all embodiments of the invention, other embodiments may be obtained according to the present embodiments without departing from the scope of the invention.
Claims (10)
1. A process for the preparation of 1, 6-hexamethylenebis (N, N-dimethylsemicarbazide), comprising the steps of:
respectively dissolving hexamethylene diisocyanate and unsymmetrical dimethylhydrazine in a polar organic solvent to respectively obtain a hexamethylene diisocyanate solution and a unsymmetrical dimethylhydrazine solution; the polar organic solvent is independently an alcohol solvent, an alkyl cyanide solvent, a halogenated hydrocarbon solvent or an ether solvent;
dropwise adding the hexamethylene diisocyanate solution into the unsymmetrical dimethylhydrazine solution to carry out nucleophilic addition reaction to obtain addition reaction feed liquid;
and (3) after solid-liquid separation of the addition reaction feed liquid, collecting solid components and drying to obtain the 1, 6-hexamethylene-bis (N, N-dimethyl semicarbazide).
2. The preparation method according to claim 1, wherein the polar organic solvent is dichloroethane or ethylene glycol dimethyl ether.
3. The process according to claim 1 or 2, wherein the polar organic solvent has a water content of < 0.1% and a purity of not less than 98%.
4. The process according to claim 1, wherein the molar ratio of hexamethylene diisocyanate to unsymmetrical dimethylhydrazine is 1 (2 to 2.1).
5. The method according to claim 1 or 2, wherein the mass ratio of the polar organic solvent to the hexamethylene diisocyanate in the hexamethylene diisocyanate solution is (3-4): 1.
6. The method according to claim 1 or 2, wherein the mass ratio of the polar organic solvent to the unsymmetrical dimethylhydrazine in the unsymmetrical dimethylhydrazine solution is (6 to 7): 1.
7. The preparation method according to claim 1, wherein the dropping speed is 5-10L/min; in the whole dropping process, the temperature of the unsymmetrical dimethylhydrazine solution is 0-30 ℃; the dropwise adding is carried out under the condition that the unsymmetrical dimethylhydrazine solution is stirred, and the stirring rotating speed is 45-75 r/min.
8. The method according to claim 1 or 7, further comprising, after the completion of the dropping: keeping the temperature and continuing the nucleophilic addition reaction; the temperature of the heat preservation is 0-30 ℃, and the time of the heat preservation is 1-1.5 h.
9. The method according to claim 1, wherein the solid-liquid separation is a centrifugal separation, and the operating parameters of the centrifugal separation include:
the centrifugal separation time is 20-30 min; the feeding speed of the centrifugal separation is 600-750 rpm; the separation rotating speed of the centrifugal separation is 1400-1600 rpm; the discharging speed of the centrifugal separation is 100-200 rpm;
the drying is vacuum drying, the temperature of the vacuum drying is 80-85 ℃, the heat preservation time of the vacuum drying is 8-8.5 h, and the pressure of the vacuum drying is less than or equal to-0.085 MPa.
10. The process according to claim 1, wherein the 1, 6-hexamethylenebis (N, N-dimethylsemicarbazide) has a color of 1 to 30 black-former, a melting point temperature of 140 to 145 ℃, a volatility of 0.1% or less and a purity of 99% or more.
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| CN103012216A (en) * | 2012-12-03 | 2013-04-03 | 西安航洁化工科技有限责任公司 | Synthetic process for yellow inhibitor HN-130 |
| CN104130162A (en) * | 2014-07-15 | 2014-11-05 | 绍兴文理学院 | Preparation method of anti-yellowing agent HN-130 |
| CN105585512A (en) * | 2014-11-13 | 2016-05-18 | 吕艳 | Synthetic process of HN-130 yellowing resistant agent |
| CN111433396A (en) * | 2017-11-21 | 2020-07-17 | 旭化成株式会社 | Polyurethane elastic fiber and yarn package thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2003211840A (en) * | 2002-01-17 | 2003-07-30 | Mitsubishi Paper Mills Ltd | Reversible heat-sensitive recording material |
| CN103012216A (en) * | 2012-12-03 | 2013-04-03 | 西安航洁化工科技有限责任公司 | Synthetic process for yellow inhibitor HN-130 |
| CN104130162A (en) * | 2014-07-15 | 2014-11-05 | 绍兴文理学院 | Preparation method of anti-yellowing agent HN-130 |
| CN105585512A (en) * | 2014-11-13 | 2016-05-18 | 吕艳 | Synthetic process of HN-130 yellowing resistant agent |
| CN111433396A (en) * | 2017-11-21 | 2020-07-17 | 旭化成株式会社 | Polyurethane elastic fiber and yarn package thereof |
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