CN113683533A - Method for preparing isocyanate monomer based on salifying phosgene method - Google Patents
Method for preparing isocyanate monomer based on salifying phosgene method Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 64
- 239000012948 isocyanate Substances 0.000 title claims abstract description 46
- 150000002513 isocyanates Chemical class 0.000 title claims abstract description 46
- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical compound ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 239000000178 monomer Substances 0.000 title claims abstract description 26
- 238000006243 chemical reaction Methods 0.000 claims abstract description 83
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 59
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 59
- 150000001412 amines Chemical class 0.000 claims abstract description 51
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims abstract description 43
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims abstract description 43
- 239000007789 gas Substances 0.000 claims abstract description 37
- 239000002904 solvent Substances 0.000 claims abstract description 33
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 29
- 239000007788 liquid Substances 0.000 claims abstract description 14
- 238000006552 photochemical reaction Methods 0.000 claims description 19
- RFFLAFLAYFXFSW-UHFFFAOYSA-N 1,2-dichlorobenzene Chemical compound ClC1=CC=CC=C1Cl RFFLAFLAYFXFSW-UHFFFAOYSA-N 0.000 claims description 18
- 239000012071 phase Substances 0.000 claims description 18
- 150000003839 salts Chemical class 0.000 claims description 15
- MVPPADPHJFYWMZ-UHFFFAOYSA-N chlorobenzene Chemical compound ClC1=CC=CC=C1 MVPPADPHJFYWMZ-UHFFFAOYSA-N 0.000 claims description 12
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 claims description 7
- FYGHSUNMUKGBRK-UHFFFAOYSA-N 1,2,3-trimethylbenzene Chemical compound CC1=CC=CC(C)=C1C FYGHSUNMUKGBRK-UHFFFAOYSA-N 0.000 claims description 6
- HMJBXEZHJUYJQY-UHFFFAOYSA-N 4-(aminomethyl)octane-1,8-diamine Chemical compound NCCCCC(CN)CCCN HMJBXEZHJUYJQY-UHFFFAOYSA-N 0.000 claims description 6
- KIDHWZJUCRJVML-UHFFFAOYSA-N putrescine Chemical compound NCCCCN KIDHWZJUCRJVML-UHFFFAOYSA-N 0.000 claims description 6
- CBCKQZAAMUWICA-UHFFFAOYSA-N 1,4-phenylenediamine Chemical compound NC1=CC=C(N)C=C1 CBCKQZAAMUWICA-UHFFFAOYSA-N 0.000 claims description 4
- SCYULBFZEHDVBN-UHFFFAOYSA-N 1,1-Dichloroethane Chemical compound CC(Cl)Cl SCYULBFZEHDVBN-UHFFFAOYSA-N 0.000 claims description 3
- RNLHGQLZWXBQNY-UHFFFAOYSA-N 3-(aminomethyl)-3,5,5-trimethylcyclohexan-1-amine Chemical compound CC1(C)CC(N)CC(C)(CN)C1 RNLHGQLZWXBQNY-UHFFFAOYSA-N 0.000 claims description 3
- VKIRRGRTJUUZHS-UHFFFAOYSA-N cyclohexane-1,4-diamine Chemical compound NC1CCC(N)CC1 VKIRRGRTJUUZHS-UHFFFAOYSA-N 0.000 claims description 3
- 239000007792 gaseous phase Substances 0.000 claims description 3
- KQSABULTKYLFEV-UHFFFAOYSA-N naphthalene-1,5-diamine Chemical compound C1=CC=C2C(N)=CC=CC2=C1N KQSABULTKYLFEV-UHFFFAOYSA-N 0.000 claims description 3
- QLBRROYTTDFLDX-UHFFFAOYSA-N [3-(aminomethyl)cyclohexyl]methanamine Chemical compound NCC1CCCC(CN)C1 QLBRROYTTDFLDX-UHFFFAOYSA-N 0.000 claims 1
- 229910001873 dinitrogen Inorganic materials 0.000 claims 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 abstract description 5
- 239000004202 carbamide Substances 0.000 abstract description 5
- 239000012535 impurity Substances 0.000 abstract description 5
- 125000003277 amino group Chemical group 0.000 abstract description 4
- 239000012299 nitrogen atmosphere Substances 0.000 abstract description 3
- 238000005054 agglomeration Methods 0.000 abstract 1
- 230000002776 aggregation Effects 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 17
- 238000003756 stirring Methods 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 7
- 238000005755 formation reaction Methods 0.000 description 6
- ALQLPWJFHRMHIU-UHFFFAOYSA-N 1,4-diisocyanatobenzene Chemical compound O=C=NC1=CC=C(N=C=O)C=C1 ALQLPWJFHRMHIU-UHFFFAOYSA-N 0.000 description 5
- 239000005057 Hexamethylene diisocyanate Substances 0.000 description 5
- RRAMGCGOFNQTLD-UHFFFAOYSA-N hexamethylene diisocyanate Chemical compound O=C=NCCCCCCN=C=O RRAMGCGOFNQTLD-UHFFFAOYSA-N 0.000 description 5
- 230000002194 synthesizing effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000000227 grinding Methods 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- SVYKKECYCPFKGB-UHFFFAOYSA-N N,N-dimethylcyclohexylamine Chemical compound CN(C)C1CCCCC1 SVYKKECYCPFKGB-UHFFFAOYSA-N 0.000 description 2
- 239000012295 chemical reaction liquid Substances 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000004817 gas chromatography Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000004811 liquid chromatography Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000004445 quantitative analysis Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- FKTHNVSLHLHISI-UHFFFAOYSA-N 1,2-bis(isocyanatomethyl)benzene Chemical compound O=C=NCC1=CC=CC=C1CN=C=O FKTHNVSLHLHISI-UHFFFAOYSA-N 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- -1 hexanediamine-o-dichlorobenzene Chemical compound 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- SWGJCIMEBVHMTA-UHFFFAOYSA-K trisodium;6-oxido-4-sulfo-5-[(4-sulfonatonaphthalen-1-yl)diazenyl]naphthalene-2-sulfonate Chemical compound [Na+].[Na+].[Na+].C1=CC=C2C(N=NC3=C4C(=CC(=CC4=CC=C3O)S([O-])(=O)=O)S([O-])(=O)=O)=CC=C(S([O-])(=O)=O)C2=C1 SWGJCIMEBVHMTA-UHFFFAOYSA-K 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C263/00—Preparation of derivatives of isocyanic acid
- C07C263/10—Preparation of derivatives of isocyanic acid by reaction of amines with carbonyl halides, e.g. with phosgene
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C263/00—Preparation of derivatives of isocyanic acid
- C07C263/18—Separation; Purification; Stabilisation; Use of additives
- C07C263/20—Separation; Purification
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The application discloses a method for preparing isocyanate monomer based on salifying phosgene method, after a mixed stream of amine and solvent is continuously introduced into a salifying reaction kettle through an upper inlet pipe inner pipe, nitrogen is continuously introduced into the salifying reaction kettle through an upper inlet pipe outer pipe, hydrogen chloride gas is dissipated into a reaction system through a porous distribution plate, the partial pressure of hydrogen chloride in a gas phase space of the salifying reaction kettle is reduced, the hydrogen chloride gas can be distributed in a radial direction and an axial direction in the system, the amine is reacted completely as far as possible, amine groups are protected, urea impurities generated by the reaction of amine which is not salified and isocyanate at high temperature in the subsequent photochemical process are avoided, the selectivity is not influenced, the isocyanate yield is further influenced, and the reaction result is not ideal, the amine can be fed in a stream atomized liquid drop shape through the arrangement of the upper inlet pipe inner pipe and the upper inlet pipe outer pipe, and hydrochloride agglomeration under most conditions can be avoided, The package, there is nitrogen atmosphere in amine atomizer, also can avoid the shower nozzle to block up the problem.
Description
Technical Field
The application relates to the field of isocyanate preparation, in particular to a method for preparing an isocyanate monomer based on a salifying phosgene method.
Background
Among the available synthesis techniques for isocyanates, phosgenation is the most common synthesis method. The methods for synthesizing isocyanate by phosgenation are mainly divided into direct phosgene method and salt-forming phosgene method. The direct phosgene method is characterized in that the isocyanate is directly generated by the reaction of amine and phosgene, and the isocyanate is easy to generate side reaction with amine group at high temperature while generating the isocyanate, so as to generate urea impurity, so that the reaction selectivity is low. However, the salt-forming phosgene method has the problem of amine coating, namely, the amine is inevitably coated in the formation process of hydrochloride crystals due to the excessively high reaction rate in the salt-forming process, and the salt-forming reaction cannot be normally carried out, so that urea impurities are generated in the next photochemical process. Therefore, the step of controlling the salt formation is a key step for synthesizing the isocyanate by the salt formation phosgene method.
Patent CN 105126711 provides a special stirring and grinding reactor, which utilizes a serrated flying-saucer-shaped movable rotating plate and a serrated stationary rotating plate to perform shearing grinding, so as to prevent hydrochloride from caking, reduce the phenomenon of amine coating, and make the hydrochloride have fine particle size, thereby improving the efficiency of subsequent photochemical reaction. But the multistage stirring of the reactor and the friction grinding of the hydrochloride occur, so that the energy consumption of the equipment is improved, the requirement on the material of the equipment is higher, and the maintenance period of the equipment is short. Patent CN 102070491 discloses a method for preparing xylylene diisocyanate by a salt-forming phosgene method, in the salt-forming process, an amine-solvent stream and a hydrogen chloride stream are mixed by using a jet reactor as a mixing device and enter a salt-forming reaction kettle for reaction, and a dilute hydrochloride solution is obtained for concentration. According to the method, the problem of blockage of a mixing pipe can be solved to a certain extent by using the amine stream with lower concentration for salt forming reaction, but the concentration of the reaction solution needs to be improved by concentrating the dilute hydrochloric acid solution subsequently, so that the operation cost is increased. Patent CN 107337615 discloses a polyester hyper-dispersant, which is added in the step of salifying to reduce the viscosity of salifying liquid and avoid the phenomena of caking, caking and the like. However, the introduction of other materials involves subsequent separation, which increases the difficulty of the process.
In the process of synthesizing isocyanate by a salifying phosgene method, the low concentration of salifying liquid can cause low efficiency of subsequent photochemical reaction, the high concentration of salifying liquid can cause overlarge viscosity of a system, and the problem of amine coating is solved. Therefore, a new process for solving the above problems is required for the salt-forming phosgene method.
Disclosure of Invention
The application provides a method for preparing an isocyanate monomer based on a salifying phosgene method, and solves the problems that in the process of synthesizing the isocyanate monomer by adopting the salifying phosgene method in the prior art, the concentration of salifying liquid is too low, so that the subsequent photochemical reaction efficiency is low, the concentration of salifying liquid is too high, so that the system viscosity is high, and amine is wrapped.
In order to solve the technical problem, the application provides a method for preparing an isocyanate monomer based on a salifying phosgene method, which comprises the following steps:
adding a solvent into a salt-forming reaction kettle, then adding nitrogen into the salt-forming reaction kettle to replace a pipeline and the salt-forming reaction kettle, and introducing dry hydrogen chloride gas into the salt-forming reaction kettle through a gas phase feeding pipe to ensure that the pressure value in the salt-forming reaction kettle is 1-3.5 bar, wherein the solvent is one or more of o-dichlorobenzene, trimethylbenzene, chlorobenzene and dichloroethane, the solvent accounts for 15-35% of the total amount in the salt-forming reaction kettle, and the feeding pressure of the hydrogen chloride gas is 1-5 bar;
continuously introducing a mixed stream of amine and a solvent into the salt-forming reaction kettle through an inner pipe of an upper inlet pipe, continuously introducing nitrogen into the salt-forming reaction kettle through an outer pipe of the upper inlet pipe to reduce the partial pressure of hydrogen chloride in a gas phase space of the salt-forming reaction kettle, maintaining the pressure for reaction for 2-6 h, stopping the reaction, and driving out excessive hydrogen chloride gas through the nitrogen through the outer pipe of the upper inlet pipe again to obtain a hydrochloride solution of the amine, wherein the mass fraction of the mixed stream of the amine and the solvent is 5-35%, the feeding pressure of the amine is 1-5 bar, the feeding pressure of the nitrogen is 1-5 bar, and the molar ratio of the amine to the hydrogen chloride is 1: 2-1: 8, the nitrogen feeding flow is 1/2-1/6 of the hydrogen chloride feeding flow, and the salt forming reaction temperature is 30-60 ℃;
adding the solvent into a photochemical reaction kettle, introducing the hydrochloride solution stream and phosgene into the photochemical reaction kettle, and carrying out photochemical reaction under the pressure condition of 4-10 bar to obtain isocyanate photochemical liquid;
carrying out light dispelling, desolventizing and rectifying treatment on the isocyanate photochemical solution to obtain an isocyanate monomer;
wherein, salify reation kettle includes the gaseous phase inlet pipe, upper portion inlet pipe inner tube and upper portion inlet pipe outer tube.
Preferably, the amine is one or more of 1, 4-butanediamine, 1, 4-phenylenediamine, 1, 5-naphthalenediamine, 1, 3-cyclohexyldimethylamine, 1, 6-hexanediamine, 1, 4-diaminocyclohexane, 1-amino-3, 3, 5-trimethyl 5-aminomethylcyclohexane, 4' -diaminodicyclohexylmethanediamine, 1, 8-diamino-4-aminomethyloctane and triaminononane.
Preferably, the solvent is the ortho-dichlorobenzene.
Preferably, the solvent accounts for 15% -25% of the total amount in the salt-forming reaction kettle.
Preferably, the feeding pressure of the hydrogen chloride gas is 2.5 bar-4 bar.
Preferably, the mass fraction of the mixed stream of the amine and the solvent is 20-35%.
Preferably, the feeding pressure of the amine is 2.5bar to 5bar, and the feeding pressure of the nitrogen is 2.5bar to 4 bar.
Preferably, the molar ratio of the amine to the hydrogen chloride is 1: 3-1: 6.
preferably, the nitrogen feeding flow rate is 1/4-1/6 of the hydrogen chloride feeding flow rate.
Preferably, the photochemical reaction pressure is 5bar to 8 bar.
Compared with the prior art, the method for preparing the isocyanate monomer based on the salt-forming phosgene method, which is provided by the application, comprises the steps of continuously introducing a mixed stream of amine and a solvent into a salt-forming reaction kettle through an upper feeding pipe inner pipe, continuously introducing nitrogen into the salt-forming reaction kettle through an upper feeding pipe outer pipe, dissipating hydrogen chloride gas into a reaction system through a porous distribution plate, reducing the partial pressure of hydrogen chloride in a gas phase space of the salt-forming reaction kettle, enabling the hydrogen chloride to be distributed in a radial direction and an axial direction in the system, completely reacting amine as far as possible, protecting an amino group so as to prevent urea impurities from being generated by the reaction of amine which is not subjected to salt formation and isocyanate at high temperature in the subsequent photochemical process, influencing selectivity and further influencing isocyanate yield to cause unsatisfactory reaction results, and enabling an amine stream to be atomized liquid drop-shaped feeding due to the arrangement of the upper feeding pipe inner pipe and the upper feeding pipe outer pipe, can avoid hydrochloride caking, parcel under most circumstances, there is nitrogen atmosphere in amine atomizer, also can avoid the shower nozzle to block up the problem.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments are briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without making any inventive changes.
FIG. 1 is a schematic structural diagram of a salt formation reaction kettle according to an embodiment of the present invention;
FIG. 2 is a schematic view of a gas phase feed pipe according to an embodiment of the present invention;
in the figure, 1 salification reaction kettle body, 2 gas phase feeding pipes, 3 stirring shafts, 4 upper feeding pipe outer pipes, 5 square grids, 6 upper feeding pipe inner pipes, 7 circular holes and 8 gas phase feeding pipe bodies.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings.
The core of the application is to provide a method for preparing an isocyanate monomer based on a salifying phosgene method, which can solve the problems that in the process of synthesizing the isocyanate monomer by adopting the salifying phosgene method in the prior art, the concentration of salifying liquid is too low, so that the subsequent photochemical reaction efficiency is low, the concentration of salifying liquid is too high, so that the system viscosity is high, and amine is wrapped.
A method for preparing isocyanate monomers based on a salifying phosgene method comprises the following steps:
s101: adding a solvent into a salt-forming reaction kettle, adding nitrogen into the salt-forming reaction kettle to replace a pipeline and the salt-forming reaction kettle, and introducing dry hydrogen chloride gas into the salt-forming reaction kettle through a gas phase inlet pipe to ensure that the pressure value in the salt-forming reaction kettle is 1-3.5 bar, wherein the solvent is one or more of o-dichlorobenzene, trimethylbenzene, chlorobenzene and dichloroethane, the solvent accounts for 15-35% of the total amount in the salt-forming reaction kettle, and the feeding pressure of the hydrogen chloride gas is 1-5 bar.
As a preferred embodiment, the solvent is ortho-dichlorobenzene. As a preferred embodiment, the solvent accounts for 15 to 25 percent of the total amount in the salt-forming reaction kettle. As a preferred embodiment, the feed pressure of the hydrogen chloride gas is between 2.5bar and 4 bar.
S102: continuously introducing mixed streams of amine and a solvent into a salt-forming reaction kettle through an upper inlet pipe inner pipe, continuously introducing nitrogen into the salt-forming reaction kettle through an upper inlet pipe outer pipe to reduce the partial pressure of hydrogen chloride in a gas phase space of the salt-forming reaction kettle, and keeping the pressure for reaction for 2 h-6 h to stop, and driving out excessive hydrogen chloride gas through the nitrogen through the upper inlet pipe outer pipe again to obtain a hydrochloride solution of the amine, wherein the mass fraction of the mixed streams of the amine and the solvent is 5% -35%, the feeding pressure of the amine is 1 bar-5 bar, the feeding pressure of the nitrogen is 1 bar-5 bar, and the molar ratio of the amine to the hydrogen chloride is 1: 2-1: 8, the nitrogen feeding flow is 1/2-1/6 of the hydrogen chloride feeding flow, and the salt forming reaction temperature is 30-60 ℃.
On the basis of the above examples, as a preferable embodiment, the amine is one or more of 1, 4-butanediamine, 1, 4-phenylenediamine, 1, 5-naphthalenediamine, 1, 3-cyclohexyldimethylamine, 1, 6-hexamethylenediamine, 1, 4-diaminocyclohexane, 1-amino-3, 3, 5-trimethyl-5-aminomethylcyclohexane, 4' -diaminodicyclohexylmethanediamine, 1, 8-diamino-4-aminomethyloctane, and triaminononane. As a preferred embodiment, the mass fraction of the mixed stream of amine and solvent is 20% to 35%. As a preferred embodiment, the feeding pressure of the amine is between 2.5 and 5bar and the feeding pressure of the nitrogen is between 2.5 and 4 bar. On the basis of the above examples, as a preferred embodiment, the molar ratio of amine to hydrogen chloride is 1: 3-1: 6. as a preferred embodiment, the nitrogen feeding flow rate is 1/4-1/6 of the hydrogen chloride feeding flow rate.
S103: and (2) adding the solvent into the photochemical reaction kettle, introducing a hydrochloride solution stream and phosgene into the photochemical reaction kettle, and carrying out photochemical reaction under the pressure condition of 4-10 bar to obtain the isocyanate photochemical liquid.
As a preferred embodiment, the photochemical reaction pressure is 5bar to 8 bar.
S104: and (3) carrying out light dispelling, desolventizing and rectifying treatment on the isocyanate photochemical solution to obtain the isocyanate monomer.
Wherein, salify reation kettle includes gaseous phase inlet pipe, upper portion inlet pipe inner tube and upper portion inlet pipe outer tube.
Fig. 1 is a schematic structural diagram of a salt formation reaction kettle according to an embodiment of the present invention, fig. 2 is a schematic structural diagram of a gas-phase feeding tube according to an embodiment of the present invention, as shown in fig. 1 to 2,
the salifying reaction kettle provided by the invention comprises a salifying reaction kettle body 1, a gas phase feeding pipe 2 embedded in a stirring shaft 3, an upper feeding pipe comprising an inner pipe and an outer pipe, namely an upper feeding pipe outer pipe 4 and an upper feeding pipe inner pipe 6, upper and lower two-stage stirring blades, wherein a square grid 5 is distributed below the bottom stirring blade, and the inside of the square grid 5 is communicated with the gas phase feeding pipe 2. Upper portion inlet pipe outer tube 4 is the reducing structure, divide into the thick footpath in top and the thin footpath of afterbody, and upper portion inlet pipe inner tube 6 is amine stream atomizer, and the 6 afterbody in upper portion inlet pipe inner tube are slightly good at to 4 afterbody positions in upper portion inlet pipe outer tube, and the ratio of the 6 internal diameters in the thick footpath of upper portion inlet pipe outer tube and upper portion inlet pipe inner tube is 1.2: 1-2.5: 1, preferably 1.5: 1-1.8: 1; the thick diameter of the upper feeding pipe outer pipe 4 is 1.1-2.0 times, preferably 1.2-1.5 times, of the thin diameter, and the length of the top of the upper feeding pipe outer pipe 4 from the top of the upper feeding pipe inner pipe 6 is 1/5-1/2 of the length of the thin diameter of the upper feeding pipe outer pipe 4. The tail end of the gas phase feeding pipe 2 is of a reducing structure and comprises a contraction section, a diffusion section and round holes 7 uniformly distributed on the pipe wall of the diffusion section, the opening rate of the round holes 7 is 30% -80%, preferably 30% -50%, and the inner diameter of the round holes 7 is 0.1-20 mm, preferably 0.1-5 mm; the ratio of the inner diameter of the gas phase feeding pipe 2 to the length of the gas phase pipe in the salifying reaction kettle body 1 is 1: 30-1: 80, preferably 1: 40-1: 60 and 8 are gas phase feed pipe bodies.
In order to make the technical solution better understood by those skilled in the art, the following detailed description is given with specific examples:
example 1
Adding 19.74kg (169.9mol) of 1, 6-hexanediamine and 46.06kg of o-dichlorobenzene into a salt-forming reaction kettle to prepare a hexanediamine-o-dichlorobenzene liquid with the mass fraction of 30 percent; 20kg of solvent dry o-dichlorobenzene is added into a salt forming reaction kettle, the kettle is started to stir, the rotating speed is set to be 280r/min, and the flow rate is set to be 1.25Nm3Introducing hydrogen chloride at a pressure of 0.2-0.25 MPa (absolute pressure) in the kettle, and introducing a 1, 6-hexamethylenediamine o-dichlorobenzene stream and nitrogen at flow rates of 16.45kg and 0.2 Nm/m3Stopping introducing the materials after 4 hours, and finishing the salt forming reaction to obtainThe concentration of the salt solution is 32.5 percent, the pressure of the salt forming kettle is reduced to 0.1Mpa, and nitrogen is introduced to expel the residual hydrogen chloride out of the system. Heating the reaction kettle to 155 ℃, introducing phosgene at the flow rate of 12.615kg/h for reaction, ensuring that the pressure in the reaction kettle is 0.6-0.7 Mpa (absolute pressure), adjusting the temperature of a condensing medium to 0 ℃, keeping the phosgene in a reflux state, stopping introducing the phosgene after reacting for 4h, and ensuring that the reaction liquid is dark red, clear and transparent and has no solid or flocculent suspended matters on the upper part. And (3) after the reaction is finished, releasing the pressure of the reaction kettle to 0.1Mpa, introducing nitrogen to drive out the residual phosgene and hydrogen chloride gas to obtain a Hexamethylene Diisocyanate (HDI) synthetic solution, and sampling to perform HDI quantitative analysis by adopting a gas chromatography and a liquid chromatography. The synthesis yield of HDI is 97.5%, and the isocyanate monomer is obtained after the HDI is subjected to light-dispelling, desolventizing and rectifying treatment.
Example 2
Adding 3.25kg (30.12mol) of 1, 4-phenylenediamine and 61.8kg of chlorobenzene into a salt-forming reaction kettle to prepare a 1, 4-phenylenediamine-chlorobenzene solution with the mass fraction of 5%; 20kg of solvent dry chlorobenzene is added into a salification reaction kettle, the kettle is started to stir, the rotating speed is set to be 280r/min, and the flow rate is set to be 0.35Nm3Introducing hydrogen chloride at a pressure of 0.15-0.20 MPa (absolute pressure) in the kettle, and introducing 1, 4-phenylenediamine-chlorobenzene flow and nitrogen at flow rates of 16.26kg and 0.1Nm3And h, stopping introducing the materials after 4h, relieving the pressure of the salification kettle to 0.1Mpa after the salification reaction is finished, and introducing nitrogen to expel the residual hydrogen chloride out of the system. And transferring the hydrochloride solution after the gas removal into a photochemical reaction kettle, heating the photochemical reaction kettle to 150 ℃, introducing phosgene at the flow rate of 9.43kg/h for reaction, ensuring that the pressure in the photochemical reaction kettle is 0.4-0.5 Mpa (absolute pressure), adjusting the temperature of a condensing medium to 0 ℃, keeping the phosgene in a backflow state, stopping introducing light after 6 hours of reaction, and ensuring that the reaction liquid is purple red, clear and transparent and has no solid or flocculent suspended matters on the upper part. And (3) after the reaction is finished, decompressing the photochemical kettle to 0.1Mpa, introducing nitrogen to drive out the residual phosgene and hydrogen chloride gas to obtain a p-phenylene diisocyanate (PPDI) synthetic solution, and sampling to perform PPDI quantitative analysis by adopting a gas chromatography and a liquid chromatography. The synthesis yield of PPDI is 98%, and finally the isocyanate monomer is obtained after the PPDI is subjected to light-dispelling, desolventizing and rectifying treatment.
After a mixed stream of amine and a solvent is continuously introduced into a salt forming reaction kettle through an upper inlet pipe inner pipe, nitrogen is continuously introduced into the salt forming reaction kettle through an upper inlet pipe outer pipe, hydrogen chloride gas is dissipated into a reaction system through a porous distribution plate, the partial pressure of hydrogen chloride in a gas phase space of the salt forming reaction kettle is reduced, the hydrogen chloride can be distributed in the system in a radial and axial two-way mode, the amine is reacted completely as far as possible, amine groups are protected, urea impurities generated by the reaction of amine which is not salified and isocyanate at high temperature in the subsequent photochemical process are avoided, the selectivity is not influenced, the isocyanate yield is further influenced, the reaction result is not ideal, the amine stream can be fed in an atomized liquid drop shape through the arrangement of the upper inlet pipe inner pipe, hydrochloride caking under most conditions can be avoided, and the reaction efficiency is improved, The package, there is nitrogen atmosphere in amine atomizer, also can avoid the shower nozzle to block up the problem.
Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims.
It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The above-described embodiments of the present application do not limit the scope of the present application.
Claims (10)
1. A method for preparing isocyanate monomers based on a salt-forming phosgene method is characterized by comprising the following steps:
adding a solvent into a salt-forming reaction kettle, then adding nitrogen into the salt-forming reaction kettle to replace a pipeline and the salt-forming reaction kettle, and introducing dry hydrogen chloride gas into the salt-forming reaction kettle through a gas phase feeding pipe to ensure that the pressure value in the salt-forming reaction kettle is 1-3.5 bar, wherein the solvent is one or more of o-dichlorobenzene, trimethylbenzene, chlorobenzene and dichloroethane, the solvent accounts for 15-35% of the total amount in the salt-forming reaction kettle, and the feeding pressure of the hydrogen chloride gas is 1-5 bar;
continuously introducing a mixed stream of amine and a solvent into the salt-forming reaction kettle through an inner pipe of an upper inlet pipe, continuously introducing nitrogen into the salt-forming reaction kettle through an outer pipe of the upper inlet pipe to reduce the partial pressure of hydrogen chloride in a gas phase space of the salt-forming reaction kettle, maintaining the pressure for reaction for 2-6 h, stopping the reaction, and driving out excessive hydrogen chloride gas through the nitrogen through the outer pipe of the upper inlet pipe again to obtain a hydrochloride solution of the amine, wherein the mass fraction of the mixed stream of the amine and the solvent is 5-35%, the feeding pressure of the amine is 1-5 bar, the feeding pressure of the nitrogen is 1-5 bar, and the molar ratio of the amine to the hydrogen chloride is 1: 2-1: 8, the nitrogen feeding flow is 1/2-1/6 of the hydrogen chloride feeding flow, and the salt forming reaction temperature is 30-60 ℃;
adding the solvent into a photochemical reaction kettle, introducing the hydrochloride solution stream and phosgene into the photochemical reaction kettle, and carrying out photochemical reaction under the pressure condition of 4-10 bar to obtain isocyanate photochemical liquid;
carrying out light dispelling, desolventizing and rectifying treatment on the isocyanate photochemical solution to obtain an isocyanate monomer;
wherein, salify reation kettle includes the gaseous phase inlet pipe, upper portion inlet pipe inner tube and upper portion inlet pipe outer tube.
2. The method for preparing isocyanate monomer based on salified phosgene method of claim 1, wherein the amine is one or more of 1, 4-butanediamine, 1, 4-phenylenediamine, 1, 5-naphthalenediamine, 1, 3-cyclohexanedimethanamine, 1, 6-hexanediamine, 1, 4-diaminocyclohexane, 1-amino-3, 3, 5-trimethyl 5-aminomethylcyclohexane, 4' -diaminodicyclohexylmethanediamine, 1, 8-diamino-4-aminomethyloctane, and triaminononane.
3. The method for preparing isocyanate monomers based on the salt-forming phosgene process of claim 1, characterized in that the solvent is the ortho-dichlorobenzene.
4. The method for preparing isocyanate monomers based on the salt-forming phosgene method as claimed in claim 1, characterized in that the solvent accounts for 15% -25% of the total amount in the salt-forming reaction kettle.
5. The method for preparing isocyanate monomers based on the salt-forming phosgene process according to claim 1, characterized in that the feed pressure of the hydrogen chloride gas is 2.5bar to 4 bar.
6. The method for preparing isocyanate monomers based on the salt-forming phosgene method as claimed in claim 1, characterized in that the mass fraction of the mixed stream of amine and the solvent is 20-35%.
7. The method for preparing isocyanate monomers based on the salt-forming phosgene method according to claim 1, characterized in that the feeding pressure of the amine is 2.5bar to 5bar, and the feeding pressure of the nitrogen is 2.5bar to 4 bar.
8. The method for preparing isocyanate monomers based on the salt-forming phosgene process according to claim 1, characterized in that the molar ratio of the amine to the hydrogen chloride is 1: 3-1: 6.
9. the method for preparing isocyanate monomers based on the salt-forming phosgene method of claim 1, characterized in that the nitrogen gas feed flow rate is 1/4-1/6 of the hydrogen chloride feed flow rate.
10. The method for preparing isocyanate monomers based on the salt-forming phosgene process according to claim 1, characterized in that the photochemical reaction pressure is 5bar to 8 bar.
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| CN114210289A (en) * | 2021-12-31 | 2022-03-22 | 夏剑锋 | Production process of p-phenylene diisocyanate |
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