CN114456091B - Device and method for preparing hexamethylene diisocyanate by pyrolysis in mixed solvent - Google Patents
Device and method for preparing hexamethylene diisocyanate by pyrolysis in mixed solvent Download PDFInfo
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- CN114456091B CN114456091B CN202111640293.6A CN202111640293A CN114456091B CN 114456091 B CN114456091 B CN 114456091B CN 202111640293 A CN202111640293 A CN 202111640293A CN 114456091 B CN114456091 B CN 114456091B
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- 239000005057 Hexamethylene diisocyanate Substances 0.000 title claims abstract description 44
- RRAMGCGOFNQTLD-UHFFFAOYSA-N hexamethylene diisocyanate Chemical compound O=C=NCCCCCCN=C=O RRAMGCGOFNQTLD-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 39
- 238000000197 pyrolysis Methods 0.000 title claims abstract description 26
- 239000012046 mixed solvent Substances 0.000 title claims abstract description 25
- 239000000047 product Substances 0.000 claims abstract description 93
- 239000002904 solvent Substances 0.000 claims abstract description 63
- 239000006227 byproduct Substances 0.000 claims abstract description 62
- 238000005979 thermal decomposition reaction Methods 0.000 claims abstract description 62
- 238000009835 boiling Methods 0.000 claims abstract description 56
- 238000000926 separation method Methods 0.000 claims abstract description 11
- ZUOUZKKEUPVFJK-UHFFFAOYSA-N diphenyl Chemical compound C1=CC=CC=C1C1=CC=CC=C1 ZUOUZKKEUPVFJK-UHFFFAOYSA-N 0.000 claims description 38
- 239000000463 material Substances 0.000 claims description 31
- 235000010290 biphenyl Nutrition 0.000 claims description 19
- 239000004305 biphenyl Substances 0.000 claims description 19
- 238000006243 chemical reaction Methods 0.000 claims description 16
- 238000002156 mixing Methods 0.000 claims description 16
- 239000002994 raw material Substances 0.000 claims description 15
- -1 methyl hexanedicarbamate Chemical compound 0.000 claims description 13
- 238000003756 stirring Methods 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 10
- 150000001298 alcohols Chemical class 0.000 claims description 8
- 239000003054 catalyst Substances 0.000 claims description 8
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 5
- AHWRBQFUPJDUMO-UHFFFAOYSA-N 6-(methoxycarbonylamino)hexylcarbamic acid Chemical compound COC(=O)NCCCCCCNC(O)=O AHWRBQFUPJDUMO-UHFFFAOYSA-N 0.000 claims description 4
- 238000002360 preparation method Methods 0.000 claims description 3
- 230000035484 reaction time Effects 0.000 claims description 3
- JNWPFPFXZSAHGD-UHFFFAOYSA-N 6-carbamoyloxyhexyl carbamate Chemical compound NC(=O)OCCCCCCOC(N)=O JNWPFPFXZSAHGD-UHFFFAOYSA-N 0.000 claims description 2
- 239000000498 cooling water Substances 0.000 claims description 2
- 238000005086 pumping Methods 0.000 claims 1
- 239000012948 isocyanate Substances 0.000 abstract description 25
- 150000002513 isocyanates Chemical class 0.000 abstract description 25
- 238000005265 energy consumption Methods 0.000 abstract description 9
- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical compound ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 abstract description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000009776 industrial production Methods 0.000 abstract description 2
- 239000000543 intermediate Substances 0.000 abstract description 2
- 239000002699 waste material Substances 0.000 abstract description 2
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 4
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 3
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- DGTNSSLYPYDJGL-UHFFFAOYSA-N phenyl isocyanate Chemical compound O=C=NC1=CC=CC=C1 DGTNSSLYPYDJGL-UHFFFAOYSA-N 0.000 description 2
- MQIUGAXCHLFZKX-UHFFFAOYSA-N Di-n-octyl phthalate Natural products CCCCCCCCOC(=O)C1=CC=CC=C1C(=O)OCCCCCCCC MQIUGAXCHLFZKX-UHFFFAOYSA-N 0.000 description 1
- BJQHLKABXJIVAM-UHFFFAOYSA-N bis(2-ethylhexyl) phthalate Chemical compound CCCCC(CC)COC(=O)C1=CC=CC=C1C(=O)OCC(CC)CCCC BJQHLKABXJIVAM-UHFFFAOYSA-N 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- MIMDHDXOBDPUQW-UHFFFAOYSA-N dioctyl decanedioate Chemical compound CCCCCCCCOC(=O)CCCCCCCCC(=O)OCCCCCCCC MIMDHDXOBDPUQW-UHFFFAOYSA-N 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000010985 leather Substances 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C263/00—Preparation of derivatives of isocyanic acid
- C07C263/04—Preparation of derivatives of isocyanic acid from or via carbamates or carbamoyl halides
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a device and a method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent, wherein a pyrolysis reactor and a product separator are organically combined together, hexamethylene diisocyanate is prepared by pyrolysis in the mixed solvent, and compared with the existing phosgene method for producing isocyanate, the device and the method solve the problem of potential safety hazard of the phosgene method; compared with the light boiling point solvent process, the energy consumption is reduced, and the energy consumption required by single separation of the solvent is 1/10 of that of the light boiling point solvent process, so that the method is environment-friendly and energy-saving; compared with the high boiling point solvent process, the secondary contact of the product and the byproducts is avoided, the yield and purity of the product are greatly improved, and the problem of energy waste caused by entrainment of thermal decomposition intermediates in the product is avoided; in addition, the invention has simple process and simple and convenient operation, and is beneficial to realizing industrial production.
Description
Technical Field
The invention relates to the technical field of isocyanate preparation, in particular to equipment and a method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent.
Background
Isocyanate is a main raw material for producing polyurethane and is widely used in the industries of elastomer, paint, plastics, pesticides, leather and the like. At present, the demand of the isocyanate in China is increased year by year, and a large amount of isocyanate is required to be imported from abroad every year to meet the demand, so the isocyanate has very broad application prospect. Isocyanate products on the market mainly include Phenylisocyanate (PI), diphenylmethane diisocyanate (MDI), toluene Diisocyanate (TDI), hexamethylene Diisocyanate (HDI), and the like.
Currently, non-phosgene methods are used to prepare isocyanates using mainly low-boiling solvents, medium-boiling solvents and high-boiling solvents. The low-boiling point solvent has strong universality, can be suitable for isocyanate such as MDI, TDI, HDI and the like, can be used in all isocyanate processes, but has large equipment volume, large investment and high energy consumption; the isocyanate is prepared by adopting the medium boiling point solvent, the application range is also wide, the method is generally applicable to various isocyanate processes, and the separation condition is harsh; in the non-isocyanate preparation process, the high-boiling point solvent system is only suitable for some isocyanates with relatively low boiling points, such as HDI and XDI, but is not suitable for MDI and NDI, but the high-boiling point solvent system has relatively low energy consumption and simple operation.
The process for preparing isocyanate by thermal decomposition without solvent (as disclosed in patent application publication No. CN 103848758A) can achieve 94.8% of isocyanate yield at the highest, and the isocyanate is solid from the polymer due to no solvent and more than 5% of isocyanate polymerization loss, so that the reactor is not easily separated, and the industrialization is difficult. The process for preparing isocyanate by thermal decomposition under a low boiling point solvent (as disclosed in patent application publication numbers CN102653517A and CN 103804236A) can achieve the highest yield of isocyanate of more than 95%, and can separate byproduct polymeric isocyanate from a reactor, is the most industrialized process at present, but has the defects of complex process, difficult separation of byproduct alcohols (because the boiling points of alcohols and solvents are different), large investment and high energy consumption, and is characterized by longer reaction time, 180min to 300min and lower reactant concentration, so that a later-stage reactor is large, an online solvent is large, and the energy consumption is high. The process for preparing isocyanate by thermal decomposition in a high boiling point solvent (as disclosed in patent applications publication numbers CN101530785A and CN101531619 a) uses high boiling point dissolution pyrolysis in CN101530785A to prepare HDI, which has a higher HDI yield, greater than 92%, but has a lower purity, mainly by secondary contact of HDI steam with alcohol steam, reducing the purity of the HDI product.
Disclosure of Invention
The first technical problem to be solved by the invention is to provide a method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent, which adopts a mixed solvent system, can overcome the difficult problem of no solvent, can solve the problems of large investment and high energy consumption in a light boiling point solvent, can reduce the secondary contact of product isocyanate and byproduct alcohols, and can improve the yield and purity of the reacted isocyanate.
The second technical problem to be solved by the invention is to provide a method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent, which can effectively improve the conversion rate and the yield of the reaction, can better realize the separation of products, is easy to realize industrialization, can realize cyclic utilization, and is environment-friendly and pollution-free.
The third technical problem to be solved by the invention is to provide equipment for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent according to the current state of the art.
The technical scheme adopted for solving the technical problems is as follows:
an apparatus for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent, comprising:
the material mixing tank is used for placing the methyl 1, 6-hexanedicarbamate and the biphenyl and heating and mixing the two;
the thermal decomposition reaction kettle is arranged at the downstream of the batching tank and connected with the batching tank through a feed pump, a catalyst and a high boiling point solvent are filled in the thermal decomposition reaction kettle, and a heating system for heating and decomposing materials in the thermal decomposition reaction kettle to form mixed steam is also arranged in the thermal decomposition reaction kettle;
the product separator is arranged at the downstream of the thermal decomposition reaction kettle and connected with the thermal decomposition reaction kettle, and is used for separating mixed steam entering the product separator into a solvent solution with a boiling point in hexamethylene diisocyanate and a solvent solution with a boiling point in byproduct alcohols; and
the product collector is connected with the product separator and is used for independently collecting the boiling point solvent solution in the hexamethylene diisocyanate and the boiling point solvent solution in the byproduct alcohol separated by the product separator.
Preferably, the product separator comprises a product condenser and a byproduct condenser which are connected in parallel, wherein the bottom of the product condenser is connected with the top of the thermal decomposition reaction kettle through a first pipeline, mixed steam generated by the thermal decomposition reaction kettle enters the product condenser for material separation, the byproduct condenser is positioned at the downstream of the product condenser, and the bottom of the byproduct condenser is connected with the top of the product condenser through a second pipeline.
Preferably, the product collector comprises a product tank and a byproduct tank, wherein the product tank is connected to the bottom of the product condenser and used for collecting the boiling point solvent solution in hexamethylene diisocyanate, and the byproduct tank is connected to the bottom of the byproduct condenser and used for collecting the boiling point solvent solution in byproduct alcohols.
Preferably, a vacuum system capable of controlling vacuum degrees in the thermal decomposition reaction kettle, the product condenser, the byproduct condenser, the product tank and the byproduct tank is connected to the top of the byproduct condenser.
Preferably, the dosing tank has a raw material feed line for feeding the raw material methyl 1, 6-hexanedicarbamate and a solvent line for feeding the medium boiling solvent biphenyl.
Preferably, a first stirring device for stirring materials is arranged in the material mixing tank; the thermal decomposition reaction kettle is internally provided with a second stirring device for stirring materials.
A method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent, comprising the following steps:
adding raw materials of 1,6 methyl hexanedicarbamate and a medium boiling point solvent biphenyl into a batching tank according to the mass ratio of 1/1, mixing the 1,6 methyl hexanedicarbamate and the biphenyl in the batching tank, and preheating to 80 ℃ to form a solution A;
the thermal decomposition reaction kettle is pre-filled with a certain amount of catalyst and high boiling point solvent, and the solution A is conveyed to 2000mL of the thermal decomposition reaction kettle by a feed pump at a certain rate;
the thermal decomposition reaction kettle, the product condenser, the byproduct condenser, the product tank and the byproduct tank are all pumped to a micro negative pressure state with the pressure of-0.005 MPa by a vacuum system, and materials in the thermal decomposition reaction kettle are heated to a reaction temperature t;
after the reaction is finished, the product tank and the byproduct tank collect the products.
Preferably, the feeding pump conveys the solution A into the thermal decomposition reaction kettle at a flow rate of 10mL/min or 12.0g/min, wherein the reaction temperature t in the thermal decomposition reaction kettle is 260 ℃, and the reaction time is 20 hours.
Preferably, the product condenser takes heat conduction oil as a medium, and condenses the product at 180 ℃; the product condenser condenses byproducts by taking normal-temperature cooling water as a medium.
Compared with the prior art, the invention has the advantages that: according to the invention, the thermal decomposition reactor and the product separator are organically combined together, hexamethylene diisocyanate is prepared by pyrolysis in a mixed solvent, and compared with the existing phosgene method for producing isocyanate, the problem of potential safety hazard of the phosgene method is solved; compared with the light boiling point solvent process, the energy consumption is reduced, and the energy consumption required by single separation of the solvent is 1/10 of that of the light boiling point solvent process, so that the method is environment-friendly and energy-saving; compared with the high boiling point solvent process, the secondary contact of the product and the byproducts is avoided, the yield and purity of the product are greatly improved, and the problem of energy waste caused by entrainment of thermal decomposition intermediates in the product is avoided; in addition, the invention has simple process and simple and convenient operation, and is beneficial to realizing industrial production.
Drawings
FIG. 1 is a process flow diagram of an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the embodiments of the drawings.
As shown in fig. 1, the apparatus for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent according to the embodiment of the present invention comprises:
a batching tank 1 for placing and heating and mixing methyl 1, 6-hexanedicarbamate and biphenyl; the material mixing tank 1 is provided with a raw material input pipeline 11 for inputting raw material 1,6 hexamethylene dicarbamate and a solvent pipeline 12 for inputting medium boiling point solvent biphenyl; a first stirring device 13 for stirring materials is arranged in the material mixing tank 1;
the thermal decomposition reaction kettle 2 is arranged at the downstream of the material mixing tank 1 and is connected with the material mixing tank 1 through a feed pump 3, a catalyst and a high boiling point solvent are filled in the thermal decomposition reaction kettle 2, and the thermal decomposition reaction kettle 2 is also provided with a heating system for heating and decomposing the materials in the thermal decomposition reaction kettle 2 to form mixed steam; the second stirring device 21 for stirring the materials is arranged in the thermal decomposition reaction kettle 2;
the product separator is arranged at the downstream of the thermal decomposition reaction kettle 2 and connected with the thermal decomposition reaction kettle 2, and is used for separating mixed steam entering the product separator into a solvent solution with a boiling point in hexamethylene diisocyanate and a solvent solution with a boiling point in byproduct alcohol;
the product collector is connected with the product separator and is used for independently collecting the boiling point solvent solution in the hexamethylene diisocyanate and the boiling point solvent solution in the byproduct alcohol separated by the product separator.
The product separator comprises a product condenser 4 and a byproduct condenser 5 which are connected in parallel, wherein the bottom of the product condenser 4 is connected with the top of the thermal decomposition reaction kettle 2 through a first pipeline 41, mixed steam generated by the thermal decomposition reaction kettle 2 enters the product condenser 4 for material separation, the byproduct condenser 5 is positioned at the downstream of the product condenser 4, and the bottom of the byproduct condenser 5 is connected with the top of the product condenser 4 through a second pipeline 51.
The product collector comprises a product tank 6 and a byproduct tank 7, wherein the product tank 6 is connected to the bottom of the product condenser 4 and is used for collecting the boiling point solvent solution in hexamethylene diisocyanate, and the byproduct tank 7 is connected to the bottom of the byproduct condenser 6 and is used for collecting the boiling point solvent solution in byproduct alcohols.
The top of the byproduct condenser 7 is connected with a vacuum system 8 capable of controlling the vacuum degree in the thermal decomposition reaction kettle 2, the product condenser 4, the byproduct condenser 5, the product tank 6 and the byproduct tank 7.
Example 1:
the method for preparing hexamethylene diisocyanate by pyrolysis in the mixed solvent comprises the following steps:
adding raw materials of 1,6 methyl hexanedicarbamate and medium boiling point solvent biphenyl into a batching tank 1 according to the mass ratio of 1/1, wherein the total addition amount of the 1,6 methyl hexanedicarbamate and the medium boiling point solvent biphenyl is 2000g, and mixing the 1,6 methyl hexanedicarbamate and the biphenyl in the batching tank 1 and preheating to 80 ℃ to form a solution A;
the thermal decomposition reaction kettle 2 is pre-filled with 50g of catalyst nano zinc oxide and 1000g of high boiling solvent dioctyl sebacate, and the solution A is conveyed to 2000mL of the thermal decomposition reaction kettle by a feed pump at a flow rate of 10 mL/min;
the thermal decomposition reaction kettle 2, the product condenser 4, the byproduct condenser 5, the product tank 6 and the byproduct tank 7 are all pumped by a vacuum system 8 to a negative pressure state with the pressure of-0.05 MPa, materials in the thermal decomposition reaction kettle 2 are heated to a reaction temperature t which is 260 ℃ for 20 hours (raw materials are needed to be timely supplemented in a batching tank);
after the reaction is finished, the materials in the thermal decomposition reaction kettle 2 are sequentially conveyed to a product condenser 4 and a byproduct condenser 5 for material separation, and finally, products are collected through a product tank 6 and byproducts are collected through a byproduct tank 7. Wherein the collection amount of the product is 9750g, the purity is 44.1 percent, the HDC conversion rate is 100 percent, and the HDI yield is 99.0 percent through calculation
Example 2:
the method for preparing hexamethylene diisocyanate by pyrolysis in the mixed solvent comprises the following steps:
adding raw materials of 1,6 methyl hexanedicarbamate and medium boiling point solvent biphenyl into a batching tank 1 according to the mass ratio of 1/1, wherein the total addition amount of the 1,6 methyl hexanedicarbamate and the medium boiling point solvent biphenyl is 2000g, and mixing the 1,6 methyl hexanedicarbamate and the biphenyl in the batching tank 1 and preheating to 80 ℃ to form a solution A;
the thermal decomposition reaction kettle 2 is pre-filled with 100g of catalyst nano Zn and 1000g of high boiling point solvent octyl phthalate, and the solution A is conveyed to 2000mL of the thermal decomposition reaction kettle by a feed pump at a flow rate of 20 mL/min;
the thermal decomposition reaction kettle 2, the product condenser 4, the byproduct condenser 5, the product tank 6 and the byproduct tank 7 are all pumped by a vacuum system 8 to a negative pressure state with the pressure of-0.06 MPa, materials in the thermal decomposition reaction kettle 2 are heated to a reaction temperature t which is 260 ℃ for 20 hours (raw materials are needed to be timely supplemented in a batching tank);
after the reaction is finished, the materials in the thermal decomposition reaction kettle 2 are sequentially conveyed to a product condenser 4 and a byproduct condenser 5 for material separation, and finally, products are collected through a product tank 6 and byproducts are collected through a byproduct tank 7. Wherein the collection amount of the product is 20130g, the purity is 41.8 percent, the HDC conversion rate is 100 percent, and the HDI yield is 96.8 percent through calculation
Example 3:
the method for preparing hexamethylene diisocyanate by pyrolysis in the mixed solvent comprises the following steps:
adding raw materials of 1,6 methyl hexanedicarbamate and medium boiling point solvent biphenyl into a batching tank 1 according to the mass ratio of 1/1, wherein the total addition amount of the 1,6 methyl hexanedicarbamate and the medium boiling point solvent biphenyl is 2000g, and mixing the 1,6 methyl hexanedicarbamate and the biphenyl in the batching tank 1 and preheating to 80 ℃ to form a solution A;
the thermal decomposition reaction kettle 2 is pre-filled with 500g of catalyst Zn-ZSM and 1000g of high boiling point solvent paraffin, and the solution A is conveyed to 2000mL of the thermal decomposition reaction kettle by a feed pump at a flow rate of 50 mL/min;
the thermal decomposition reaction kettle 2, the product condenser 4, the byproduct condenser 5, the product tank 6 and the byproduct tank 7 are all pumped to a micro negative pressure state with the pressure of-0.005 MPa by a vacuum system 8, materials in the thermal decomposition reaction kettle 2 are heated to a reaction temperature t which is 260 ℃ and react for 20 hours (raw materials are needed to be timely supplemented in a batching tank);
after the reaction is finished, the materials in the thermal decomposition reaction kettle 2 are sequentially conveyed to a product condenser 4 and a byproduct condenser 5 for material separation, and finally, products are collected through a product tank 6 and byproducts are collected through a byproduct tank 7. Wherein, the collection amount of the product is 50792g, the purity is 40.2 percent, the HDC conversion rate is 100 percent and the HDI yield is 94.0 percent.
Claims (9)
1. A method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent, which is characterized by comprising the following steps:
adding raw materials of 1,6 methyl hexanedicarbamate and a medium boiling point solvent biphenyl into a batching tank according to the mass ratio of 1/1, mixing the 1,6 methyl hexanedicarbamate and the biphenyl in the batching tank, and preheating to 80 ℃ to form a solution A;
the thermal decomposition reaction kettle is pre-filled with a certain amount of catalyst and high boiling point solvent, and the solution A is conveyed to 2000mL of the thermal decomposition reaction kettle by a feed pump at a certain rate;
pumping the thermal decomposition reaction kettle to a micro negative pressure state with the pressure of-0.005 MPa by a vacuum system, heating the materials in the thermal decomposition reaction kettle to a reaction temperature t, wherein t is 260 ℃, and the reaction time is 20 hours;
after the reaction is finished, the product tank and the byproduct tank collect the products.
2. The method for preparing hexamethylene diisocyanate by pyrolysis in mixed solvent according to claim 1, wherein: the adopted equipment comprises
The material mixing tank is used for placing the methyl 1, 6-hexanedicarbamate and the biphenyl and heating and mixing the two;
the thermal decomposition reaction kettle is arranged at the downstream of the batching tank and connected with the batching tank through a feed pump, a catalyst and a high boiling point solvent are filled in the thermal decomposition reaction kettle, and a heating system for heating and decomposing materials in the thermal decomposition reaction kettle to form mixed steam is also arranged in the thermal decomposition reaction kettle;
the product separator is arranged at the downstream of the thermal decomposition reaction kettle and connected with the thermal decomposition reaction kettle, and is used for separating mixed steam entering the product separator into a solvent solution with a boiling point in hexamethylene diisocyanate and a solvent solution with a boiling point in byproduct alcohols; and
the product collector is connected with the product separator and is used for independently collecting the boiling point solvent solution in the hexamethylene diisocyanate and the boiling point solvent solution in the byproduct alcohol separated by the product separator.
3. The method for preparing hexamethylene diisocyanate by pyrolysis in mixed solvent according to claim 2, wherein: the product separator comprises a product condenser and a byproduct condenser which are connected in parallel, wherein the bottom of the product condenser is connected with the top of the thermal decomposition reaction kettle through a first pipeline, mixed steam generated by the thermal decomposition reaction kettle enters the product condenser for material separation, the byproduct condenser is positioned at the downstream of the product condenser, and the bottom of the byproduct condenser is connected with the top of the product condenser through a second pipeline.
4. A process for the preparation of hexamethylene diisocyanate by pyrolysis in a mixed solvent according to claim 3, characterized in that: the product collector comprises a product tank and a byproduct tank, wherein the product tank is connected to the bottom of the product condenser and used for collecting the boiling point solvent solution in hexamethylene diisocyanate, and the byproduct tank is connected to the bottom of the byproduct condenser and used for collecting the boiling point solvent solution in byproduct alcohols.
5. The method for preparing hexamethylene diisocyanate by pyrolysis in mixed solvent according to claim 4, wherein: the top of the byproduct condenser is connected with a vacuum system which can control the vacuum degree in the thermal decomposition reaction kettle, the product condenser, the byproduct condenser, the product tank and the byproduct tank.
6. The method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent according to any one of claims 2 to 5, wherein: the batching tank is provided with a raw material input pipeline for inputting raw material 1,6 hexamethylene dicarbamate and a solvent pipeline for inputting medium boiling point solvent biphenyl.
7. The method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent according to any one of claims 2 to 5, wherein: a first stirring device for stirring materials is arranged in the material mixing tank; the thermal decomposition reaction kettle is internally provided with a second stirring device for stirring materials.
8. The method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent according to any one of claims 1 to 5, wherein: the feed pump delivers the solution A into the thermal decomposition reaction kettle at a flow rate of 10mL/min or 12.0 g/min.
9. The method for preparing hexamethylene diisocyanate by pyrolysis in a mixed solvent according to any one of claims 1 to 5, wherein: the product condenser takes heat conduction oil as a medium and condenses products at 180 ℃; the product condenser condenses byproducts by taking normal-temperature cooling water as a medium.
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| CN102653517A (en) * | 2011-03-02 | 2012-09-05 | 中国科学院过程工程研究所 | Method for preparing isocyanate from carbamate |
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| US8680323B2 (en) * | 2010-01-19 | 2014-03-25 | Basf Se | Process for preparing isocyanates by thermal dissociation of carbamates |
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