CN112390730B

CN112390730B - Preparation method of methylcyclohexyl diisocyanate based on reduced pressure fractionation

Info

Publication number: CN112390730B
Application number: CN202011286305.5A
Authority: CN
Inventors: 夏剑锋; 夏晨东; 陈国全; 傅华伟; 周裕民; 陈丽君; 冯洪伟; 陈映波; 林玮
Original assignee: Upchem China Co ltd
Current assignee: Upchem China Co ltd
Priority date: 2018-09-13
Filing date: 2018-09-13
Publication date: 2022-06-21
Anticipated expiration: 2038-09-13
Also published as: CN109053493A; CN112390730A; CN109053493B

Abstract

The application discloses a preparation method of methyl cyclohexyl diisocyanate and a reaction kettle, wherein the preparation reaction kettle provided by the invention comprises the following steps: the device comprises a reaction tank, a plurality of electromagnet assemblies, plastic balls, a plurality of blades, a plurality of copper bars and a plurality of permanent magnets; the copper bar is fixedly arranged at the bottom of the reaction tank, the bottom of the reaction tank is made of a non-ferrous material, the permanent magnet is fixedly arranged in the plastic ball, the plastic ball is provided with a through hole, the plastic ball is sleeved on the copper bar in a sliding manner through the through hole, and the blades are arranged on the outer wall of the plastic ball; a spiral groove is formed in the outer wall of the copper rod, a sliding ball is fixedly arranged on the plastic ball, and the sliding ball is located in the spiral groove; the electromagnet assembly is movably or fixedly arranged outside the reaction tank, the copper bar and the electromagnet assembly are respectively positioned on two sides of the bottom of the tank, and the electromagnet assembly is used for driving the plastic balls to rotate and move along the copper bar.

Description

Preparation method of methylcyclohexyl diisocyanate based on reduced pressure fractionation

The application is a divisional application with the application date of 09 and 13 in 2018, the application number of 2018110700164 and the patent name of 'preparation method of methylcyclohexyl diisocyanate'.

Technical Field

The invention relates to the technical field of chemical industry, in particular to a preparation method of methylcyclohexyl diisocyanate based on reduced pressure fractionation.

Background

Methylcyclohexyl diisocyanate is a chemical raw material, and a polyurethane product prepared from the methylcyclohexyl diisocyanate has excellent characteristics of no yellowing, light stability, weather resistance, high mechanical properties and the like, so that methylcyclohexyl diisocyanate is a widely used chemical raw material.

The prior production method of methyl cyclohexyl diisocyanate utilizes a phosgene synthesis method, but phosgene is a highly toxic gas, has low boiling point and high volatility, and has great danger in the processes of use, transportation and storage, and the phosgene usage amount is very large when the phosgene is utilized for production, and the reaction temperature is as high as 300-500 ℃, so that the production energy consumption is high, and the production efficiency is low.

Disclosure of Invention

The invention provides a preparation method of methylcyclohexyl diisocyanate based on reduced pressure fractionation, aiming at the problems.

The technical scheme adopted by the invention is as follows:

1. a method for preparing methylcyclohexyl diisocyanate comprises the following steps:

s1: the method comprises the steps of taking methylcyclohexyldiamine or methylcyclohexyldiamine salt or a mixture of the methylcyclohexyldiamine and the methylcyclohexyldiamine salt as a first preparation raw material, taking bis (trichloromethyl) carbonate or trichloromethyl chloroformate or a mixture of the bis (trichloromethyl) carbonate and the trichloromethyl chloroformate as a second preparation raw material, and mixing the first preparation raw material and the second preparation raw material in an inert solvent.

S2: maintaining the mixture of the first preparation raw material and the second preparation raw material at 0-70 ℃ for reaction for 0-4 h, and raising the reaction temperature to 100-170 ℃ for reaction for 0-4 h.

S3: the reaction product obtained in step S2 was subjected to fractional distillation under reduced pressure.

In the scheme, phosgene is not used as a production raw material, bis (trichloromethyl) carbonate or trichloromethyl chloroformate is used to replace phosgene, the bis (trichloromethyl) carbonate is a relatively stable solid, and the trichloromethyl chloroformate is a liquid, and the two substances are safer and more stable than phosgene. The chemical reaction process in the scheme is mainly divided into two steps, wherein the first step is acylation reaction within the range of 0-70 ℃; the second step is dehydrochlorination reaction after acylation reaction, and the reaction temperature is 100-170 ℃.

In the scheme, phosgene is not adopted as a production raw material, and production is carried out at a relatively low temperature, so that the production energy consumption is lower, and the safety coefficient is higher.

A reaction kettle for preparing methyl cyclohexyl diisocyanate comprises a reaction tank, a plurality of electromagnet assemblies, plastic balls, a plurality of blades, a plurality of copper bars and a plurality of permanent magnets; the copper bar is fixedly arranged at the bottom of the reaction tank, the bottom of the reaction tank is made of a non-ferrous material, the permanent magnet is fixedly arranged in the plastic ball, the plastic ball is provided with a through hole, the plastic ball is sleeved on the copper bar in a sliding manner through the through hole, and the blades are arranged on the outer wall of the plastic ball; a spiral groove is formed in the outer wall of the copper rod, a sliding ball is fixedly arranged on the plastic ball, and the sliding ball is located in the spiral groove; the electromagnet assembly is movably or fixedly arranged outside the reaction tank, the copper bar and the electromagnet assembly are respectively positioned on two sides of the bottom of the tank, and the electromagnet assembly is used for driving the plastic ball to rotate and move along the copper bar at the same time.

Because the production process provided by the scheme is a brand-new production process, a reaction kettle is designed based on the production process.

In a traditional chemical reaction vessel, a rotating shaft is arranged on a reaction tank, a paddle is arranged on the rotating shaft, and when the rotating shaft rotates, the paddle stirs liquid in the reaction tank to rotate around the rotating shaft. Two main problems are associated with this type of reaction vessel: the first problem is the sealing problem between the rotating shaft and the reaction tank, because the driving motor is generally arranged outside the reaction tank, the rotating shaft and the reaction tank cannot be completely sealed, and a part of gas in the reaction tank must be dissipated; the second problem is that the paddle only moves left and right while agitating the liquid, and does not move the liquid up and down, which causes a large concentration difference between the upper and lower layers of liquid in the reaction tank.

The reaction kettle provided by the device has the advantages that the reaction kettle is provided with a copper rod (not only limited to the copper rod, but also a high-temperature-resistant and corrosion-resistant plastic rod, and also a metal rod such as magnesium aluminum alloy and the like), the copper rod is vertical to the bottom of the reaction kettle, the copper rod is sleeved with a plastic ball (not only limited to the plastic ball, and the plastic ball is selected for light plastic, and can be replaced by the copper ball, the magnesium aluminum alloy ball or a cement ball), a magnet block is fixed in the plastic ball, an electromagnet group positioned outside the reaction kettle drives the plastic ball on the copper rod to move along the copper rod by changing the orientation of the magnetic pole of the electromagnet group, when the plastic ball moves towards the top side of the kettle, liquid above the plastic ball can enter below the plastic ball, and when the plastic ball moves from the top side to the bottom side of the kettle, liquid below the plastic ball can move towards the top of the plastic ball, therefore, the liquid in the reaction tank flows up and down, the plastic balls rotate along the copper bars, and the blades are arranged on the plastic balls, so that the liquid can be stirred to move left and right. Therefore, the device can stir the liquid in the reaction tank to move up and down, left and right, so that the concentration of the liquid in the reaction tank is more uniform. Meanwhile, in order to fully stir the liquid in the reaction tank, a plurality of groups of copper rods and plastic balls are arranged in the reaction tank, and each plastic ball is provided with an electromagnet assembly. The magnet block is iron-chromium-cobalt magnet block, and can not lose magnetism at high temperature of 500 ℃.

Because the rotating shaft is not arranged in the reaction tank, the reaction tank has good sealing performance, and meanwhile, the liquid in the reaction tank can move up and down, left and right, so that the concentration difference and the temperature difference of the solution at each position in the reaction tank are smaller.

Optionally, the plastic ball is a polyphenylene sulfide plastic ball or a polysulfone plastic ball, and the sliding bead is a polyphenylene sulfide sliding bead or a polysulfone plastic sliding bead; the copper bar is a hollow copper bar, the copper bar and the copper bar are communicated together in a sealing mode through a heat conduction pipe, and the copper bar and the heat conduction pipe are used for circulating steam.

Because liquid needs to be heated in the reaction process, steam is very suitable for heating the liquid in the reaction tank as an ideal heat carrier, and the copper rod is a hollow copper rod, so that the heat conduction can be realized, and the steam can transfer the heat of the steam to the liquid in the reaction tank when circulating in the copper rod and the heat conduction pipe. Specifically, two heat pipes (one heat pipe is used for a passage for steam to enter the reaction tank, and the other heat pipe is used for a passage for steam to leave the reaction tank) are connected outside the reaction tank, and the two heat pipes are respectively communicated with the copper rod.

Optionally, the device further comprises a telescopic rod and a hose; the telescopic rod is a pneumatic telescopic rod or a hydraulic telescopic rod, one end of the telescopic rod is fixed at the tank top of the reaction tank, and the other end of the telescopic rod is fixed with a temperature probe which is used for detecting the temperature of liquid in the tank; one pipe orifice of the hose is fixed on the telescopic rod and is positioned near the temperature probe, the other pipe orifice of the hose is positioned outside the reaction tank, and sealant is coated at the gap between the hose and the tank wall of the reaction tank.

The pneumatic telescopic rod is a common pneumatic rod and belongs to the prior art, and the hydraulic telescopic rod is a common hydraulic rod and also belongs to the prior art. The temperature probe is arranged on the hydraulic rod so as to conveniently measure the liquid temperatures at different depths in the tank, and the hose is used for sampling samples in the tank.

Optionally, the ball spring assembly further comprises a plurality of ball springs, the ball springs are made of nonferrous materials, the ball springs are fixedly sleeved on the copper bar, and the ball springs are respectively located on two sides of the plastic ball.

The ball spring may be plastic.

Optionally, the device further comprises a sleeve made of a non-ferrous material and an impact roller made of a non-ferrous material; the sleeve is arranged at the tank top of the reaction tank, the tank top is made of nonferrous materials, one opening of the sleeve is fixedly connected with the feed inlet of the reaction tank, and the other opening of the sleeve is positioned in the reaction tank; the impact roller is movably arranged in the sleeve, a round sliding column is arranged on the outer wall surface of the impact roller, a circular arc-shaped slide way penetrating through the wall of the sleeve is formed in the sleeve, the round sliding column is positioned in the slide way, and the slide way and the round sliding column are matched with each other to prevent the impact roller from falling out of the sleeve; an iron block is arranged in the impact roller, a plurality of groups of electromagnet assemblies are arranged at the peripheral edge of the outer cylinder wall of the sleeve, the electromagnet assemblies on the sleeve are used for driving the impact roller to move in the sleeve, and a gap between the sleeve and the impact roller is a passage for solid particle raw materials to enter the reaction tank; the round sliding column is sleeved with a column spring, one end of the column spring is fixed to the outer wall of the impact roller, and the column spring is used for organizing the impact roller to directly impact the sleeve.

Because the salt of the methylcyclohexyldiamine is solid particles, the bis (trichloromethyl) carbonate is also solid particles, and the solid particles can be stacked into blocks due to the action of gravity in the storage process, reactants need to be supplemented in the reaction process, and the blocky solid particles are slowly dissolved after entering a reaction tank, so that the reaction speed can be seriously reduced.

It needs to be further explained that the electromagnetic component control device further comprises a PLC controller, and the PLC controller is used for coordinating the working state of each electromagnetic component.

Optionally, the reaction tank further comprises a filtering device, the filtering device is hermetically installed at the discharge port of the reaction tank, and the filtering device is used for filtering solid particle impurities in the reaction product; the filtering device comprises a round sleeve, a screen column and a hydraulic rod, wherein the outer wall of the round sleeve is hermetically matched with a discharge hole of the reaction tank through threads; the screen column is arranged in the round sleeve in a sliding mode, the outer cylinder wall of the screen column is tightly attached to the inner wall of the round sleeve, one end of the hydraulic rod is fixed on the round sleeve in a sealing mode, the other end of the hydraulic rod is fixed with the screen column together, the hydraulic rod is used for driving the screen column to move in the round sleeve, the round sleeve is connected with a guide pipe, and liquid in the round sleeve leaves the round sleeve through the guide pipe.

The commonly used filtering method of the chemical reaction tank at present is to arrange a filter screen at the discharge port, and the method is easy to accumulate solid particles on meshes of the filter screen, so that the filter screen is blocked and loses the filtering function. In this scheme, the screen cloth post is totally closed, but all on the round side face and two circle terminal surfaces of screen cloth post the cloth have the mesh densely, in this device, because the hydraulic stem drive screen cloth post is moving in the circle cover for the round side face of screen cloth post can be scraped by the circle cover constantly and ground, can guarantee that the round side face of screen cloth post can not pile up solid particle thing, guarantees that the liquid energy source in the retort gets into in the circle cover via the screen cloth post constantly, again from the pipe on the circle cover leave the circle cover.

Optionally, the reaction kettle further comprises a cooling reflux device, wherein the cooling reflux device is installed at the top of the reaction tank and is used for refluxing the evaporated reaction liquid; the cooling reflux device comprises an inner pipe and an outer pipe, the inner pipe is arranged in the outer pipe, two pipe orifices of the inner pipe are both positioned outside the outer pipe, and the inner pipe is used for introducing cooling liquid; one pipe orifice of the outer pipe is communicated with the reaction tank, the other pipe orifice of the outer pipe is closed, and a plurality of semiconductor thermoelectric materials are arranged on the pipe wall of the outer pipe.

The traditional condenser pipe is characterized in that an inner pipe is used for backflow, cold water is filled in a gap between the inner pipe and an outer pipe, and the condensing efficiency of the condenser pipe is low. In the above-described cooling reflux apparatus, the cooling liquid (usually water) is circulated through the inner pipe, and the gap between the inner pipe and the outer pipe is used for reflux; meanwhile, the semiconductor thermoelectric material is arranged on the pipe wall of the outer pipe, and because a great temperature difference exists between the inside and the outside of the outer pipe, the temperature difference can be utilized to generate electricity, so the semiconductor thermoelectric material (block-shaped) is arranged on the pipe wall of the outer pipe. Because one part of the heat of the reflux is transferred to the cooling liquid and the other part is converted into electric energy, the cooling reflux efficiency is higher and the reflux speed is higher. Two orifices of the specific inner pipe are arranged on the outer side of the outer pipe, and the purpose of the design is to enable cooling water to smoothly enter the inner pipe.

Optionally, still include adsorption tube and liquefaction jar, adsorption tube one end meets with the retort, and the adsorption tube other end meets with the liquefaction jar, and the adsorption tube intussuseption is filled with a plurality of cotton plugs that are stained with water, and is provided with the one-way device that switches on in the adsorption tube, the one-way device that switches on is used for guaranteeing that gaseous by the one-way flow direction liquefaction jar of adsorption tube, be provided with a plurality of PET membrane bags in the liquefaction jar, and the jar wall of PET membrane bag and liquefaction jar is sealed to be joined in marriage together, and the sack of PET membrane bag is located outside the liquefaction jar.

Because need to dry to by distillation inert solvent before carrying out the decompression separation operation, can use inert solvent altogether 3 in this production technology (choose for use one kind can), i.e. o-dichlorobenzene, chlorobenzene and benzonitrile, because there is certain hydrogen chloride gas production at the in-process of evaporating inert solvent, so hydrogen chloride when handling, so fill the cotton stopper of being stained with water in the adsorption tube, because hydrogen chloride gas is very easily dissolved in water, hydrogen chloride gas can be adsorbed by water when the cotton stopper is passed through, because be equipped with one-way conduction device (being the check valve) on the adsorption tube, belong to prior art, the gas in the adsorption tube only can flow to in the liquefaction jar, and the gas in the liquefaction jar can not flow to in the adsorption tube. When the intraductal gas of adsorption constantly gets into the liquefaction jar in, begin to fill low temperature water (being less than 25 ℃) into the PET membrane bag, the PET membrane bag takes place the inflation constantly into in the low temperature water source, make the space in the liquefaction jar diminish, just so played certain extrusion to the inert solvent steam in the liquefaction jar, simultaneously because the water in the PET membrane bag has good cooling effect, so under the combined action of high pressure and low temperature water, inert solvent steam can liquefy fast in the liquefaction jar, can further retrieve after the liquefaction and recycle. The specific installation method can be to open on the liquefaction jar, then glue the mode of gluing PET membrane bag on the opening of liquefaction jar through the glue.

The invention has the beneficial effects that: phosgene is not used as a production raw material, and the production is carried out at a relatively low temperature, so that the production energy consumption is lower, and the safety factor is higher.

Description of the drawings:

FIG. 1 is a schematic diagram of a methyl cyclohexyl diisocyanate preparation reaction kettle structure;

FIG. 2 is a schematic diagram of a plastic ball mounting arrangement;

FIG. 3 is an enlarged schematic view at A in FIG. 2;

FIG. 4 is a schematic diagram of the structure of a copper bar;

FIG. 5 is a schematic view of a filter mounting arrangement;

FIG. 6 is a side view of the sleeve as installed on the top of the can;

FIG. 7 is a schematic cross-sectional view taken along line B-B of FIG. 6;

FIG. 8 is a schematic diagram of a cooling reflux unit mounting arrangement;

fig. 9 is a schematic view showing the installation relationship between the PET film bag and the liquefaction tank.

The figures are numbered: 1. the reaction tank comprises a reaction tank body, 101, a tank bottom, 102, a tank top, 2, an electromagnet assembly, 3, plastic balls, 301, sliding balls, 4, blades, 5, copper bars, 501, spiral grooves, 6, permanent magnets, 7, a heat conduction pipe, 8, telescopic rods, 901, ball springs, 902, column springs, 10, a sleeve, 1001, a slide way, 11, an impact roller, 1101, a smooth column, 12, an iron block, 13, a round sleeve, 14, a screen column, 15, a hydraulic rod, 16, an inner tube, 17, an outer tube, 18, a semiconductor thermoelectric material, 19, an adsorption tube, 20, a liquefaction tank, 21 and a PET film bag.

The specific implementation mode is as follows:

the present invention will be described in detail below with reference to the accompanying drawings.

The invention provides a preparation method of methyl cyclohexyl diisocyanate and a reaction kettle, wherein the preparation reaction kettle of the methyl cyclohexyl diisocyanate is as follows:

as shown in attached figures 1, 2, 3 and 4, the methyl cyclohexyl diisocyanate preparation reaction kettle comprises a reaction tank 1, a plurality of electromagnet assemblies 2, plastic balls 3, a plurality of blades 4, a plurality of copper bars 5 and a plurality of permanent magnets 6; the copper bar 5 is fixedly arranged at the tank bottom 101 of the reaction tank 1, the tank bottom 101 of the reaction tank 1 is made of a non-ferrous material, the permanent magnet 6 is fixedly arranged in the plastic ball 3, a through hole is formed in the plastic ball 3, the plastic ball 3 is sleeved on the copper bar 5 in a sliding mode through the through hole, and the blade 4 is arranged on the outer wall of the plastic ball 3; a spiral groove 501 is formed in the outer wall of the copper rod 5, a sliding ball 301 is fixedly arranged on the plastic ball 3, and the sliding ball 301 is located in the spiral groove 501; the electromagnet assembly 2 is movably or fixedly arranged outside the reaction tank 1, the copper bar 5 and the electromagnet assembly 2 are respectively positioned on two sides of the tank bottom 101, and the electromagnet assembly 2 is used for driving the plastic balls 3 to rotate and move along the copper bar 5.

In a traditional chemical reaction vessel, a rotating shaft is arranged on a reaction tank 1, and then a paddle is arranged on the rotating shaft, and when the rotating shaft rotates, the paddle stirs liquid in the reaction tank 1 to rotate around the rotating shaft. Two main problems are associated with this type of reaction vessel: the first problem is the sealing problem between the rotating shaft and the reaction tank 1, because the driving motor is generally arranged outside the reaction tank 1, the rotating shaft and the reaction tank 1 cannot be completely sealed, and a part of gas in the reaction tank 1 must be dissipated; the second problem is that the paddle agitates the liquid by moving it only left and right without moving it up and down, which causes a large concentration difference between the upper and lower layers of liquid in the reaction tank 1.

The reaction kettle provided by the device has the advantages that the reaction kettle 1 is provided with the copper rod 5 (not only the copper rod 5, but also a high-temperature-resistant and corrosion-resistant plastic rod, a metal rod such as magnesium aluminum alloy and the like), the copper rod 5 is vertical to the bottom 101 of the reaction kettle 1, the copper rod 5 is sleeved with the plastic ball 3 (not only the plastic ball 3 is selected, the plastic ball 3 is selected for light plastic, and can be replaced by the copper ball, the magnesium aluminum alloy ball or the cement ball), the magnet block 12 is fixed in the plastic ball 3, the electromagnet group positioned outside the reaction kettle 1 drives the plastic ball 3 on the copper rod 5 to move along the copper rod 5 by changing the orientation of the magnetic pole of the electromagnet, when the plastic ball 3 moves towards the top 102 side, the liquid above the plastic ball 3 enters the plastic ball 3, and when the plastic ball 3 moves towards the bottom 101 side from the top 102 side, the liquid below the plastic balls 3 moves towards the upper part of the plastic balls 3, so that the liquid in the reaction tank 1 flows up and down, meanwhile, the plastic balls 3 rotate along the copper bars 5, and the blades 4 are arranged on the plastic balls 3, so that the liquid can be stirred to move left and right. Therefore, the device can stir the liquid in the reaction tank 1 to move up and down, left and right, so that the concentration of the liquid in the reaction tank 1 is more uniform. Meanwhile, in order to fully stir the liquid in the reaction tank 1, a plurality of groups of copper rods 5 and plastic balls 3 are arranged in the reaction tank 1, and each plastic ball 3 is provided with one electromagnet assembly 2. The magnet block 12 is a ferrochrome-cobalt magnet block 12, which can not lose magnetism at a high temperature of 500 ℃.

Because do not set up the pivot in the retort 1 for retort 1 has good leakproofness, and the liquid that can be in the retort 1 moves from top to bottom and from side to side simultaneously has guaranteed that solution concentration difference and the difference in temperature are littleer everywhere in the retort 1.

As shown in fig. 2 and 3, the plastic ball 3 is a polyphenylene sulfide plastic ball 3 or a polysulfone plastic ball 3, and the sliding bead 301 is a polyphenylene sulfide sliding bead 301 or a polysulfone sliding bead 301; the copper rod 5 is a hollow copper rod 5, the copper rod 5 and the copper rod 5 are hermetically communicated through a heat conduction pipe 7, and the copper rod 5 and the heat conduction pipe 7 are used for circulating steam.

Because the liquid needs to be heated in the reaction process, and the steam is very suitable for heating the liquid in the reaction tank 1 as a very ideal heat carrier, the copper rod 5 is a hollow copper rod 5 and can be used for heat conduction, and the steam can transfer the heat of the steam to the liquid in the reaction tank 1 when circulating in the copper rod 5 and the heat conduction pipe 7. Specifically, two heat pipes 7 (one heat pipe 7 is used for a passage of vapor entering the reaction tank 1, and the other heat pipe 7 is used for a passage of vapor leaving the reaction tank 1) are connected outside the reaction tank 1, and the two heat pipes 7 are respectively communicated with the copper rod 5.

As shown in the attached figure 1, the device also comprises a telescopic rod 8 and a hose; the telescopic rod 8 is a pneumatic telescopic rod 8 or a hydraulic telescopic rod 8, one end of the telescopic rod 8 is fixed at the tank top 102 of the reaction tank 1, and the other end of the telescopic rod 8 is fixed with a temperature probe which is used for detecting the temperature of liquid in the tank; one pipe orifice of the hose is fixed on the telescopic rod 8 and is positioned near the temperature probe, the other pipe orifice of the hose is positioned outside the reaction tank 1, and sealant is coated at the gap between the hose and the tank wall of the reaction tank 1.

The pneumatic telescopic rod 8 is a common pneumatic rod and belongs to the prior art, and the hydraulic telescopic rod 8 is a common hydraulic rod 15 and also belongs to the prior art. The temperature probes are mounted on the hydraulic rod 15 for the purpose of conveniently measuring the liquid temperatures at different depths in the tank, and the hose is used for sampling samples in the tank.

As shown in fig. 1 and 2, the ball spring device further includes a plurality of ball springs 901, the ball springs 901 are made of nonferrous materials, the ball springs 901 are fixedly sleeved on the copper bar 5, and the ball springs 901 are respectively located at two sides of the plastic ball 3.

The ball spring 901 may be a plastic ball spring.

As shown in fig. 6 and 7, the impact roller further comprises a sleeve 10 made of a non-ferrous material and an impact roller 11 made of a non-ferrous material; the sleeve 10 is arranged at the tank top 102 of the reaction tank 1, the tank top 102 is made of a non-iron material, one opening of the sleeve 10 is fixedly connected with the feeding hole of the reaction tank 1, and the other opening of the sleeve 10 is positioned in the reaction tank 1; the impact roller 11 is movably arranged in the sleeve 10, a round sliding column 1101 is arranged on the outer wall surface of the impact roller 11, a circular arc-shaped sliding way 1001 penetrating through the wall of the sleeve 10 is formed in the sleeve 10, the round sliding column 1101 is located in the sliding way 1001, and the sliding way 1001 and the round sliding column are matched with each other to prevent the impact roller 11 from falling out of the sleeve 10; an iron block 12 is arranged in the impact roller 11, a plurality of groups of electromagnet assemblies 2 are arranged at the peripheral edge of the outer cylinder wall of the sleeve 10, the electromagnet assemblies 2 on the sleeve 10 are used for driving the impact roller 11 to move in the sleeve 10, and a gap between the sleeve 10 and the impact roller 11 is a passage for solid particle raw materials to enter the reaction tank 1; cylindrical spring 902 is sleeved on cylindrical column 1101, one end of cylindrical spring 902 is fixed on the outer wall of impact roller 11, and cylindrical spring 902 is used for directly impacting sleeve 10 by tissue impact roller 11.

Because the salt of the methylcyclohexyldiamine is solid particles, the bis (trichloromethyl) carbonate is also solid particles, and the solid particles are stacked into blocks due to the action of gravity in the storage process, reactants need to be supplemented in the reaction process, and the block solid particles are dissolved slowly after entering the reaction tank 1, so that the reaction speed can be reduced seriously.

It needs to be further explained that the electromagnetic assembly further comprises a PLC controller, and the PLC controller is used for coordinating the working state of each electromagnet assembly 2.

As shown in the attached figures 1 and 5, the device further comprises a filtering device, wherein the filtering device is hermetically arranged at the discharge port of the reaction tank 1 and is used for filtering solid particle impurities in a reaction product; the filtering device comprises a round sleeve 13, a screen column 14 and a hydraulic rod 15, wherein the outer wall of the round sleeve 13 is hermetically matched with a discharge hole of the reaction tank 1 through threads; the screen column 14 is arranged in the round sleeve 13 in a sliding mode, the outer cylinder wall of the screen column 14 is tightly attached to the inner wall of the round sleeve 13, one end of a hydraulic rod 15 is fixed on the round sleeve 13 in a sealing mode, the other end of the hydraulic rod 15 is fixed with the screen column 14, the hydraulic rod 15 is used for driving the screen column 14 to move in the round sleeve 13, a guide pipe is connected onto the round sleeve 13, and liquid in the round sleeve 13 leaves the round sleeve 13 through the guide pipe.

The commonly used filtering method of the chemical reaction tank 1 at present is to arrange a filter screen at the discharge port, and the method is easy to accumulate solid particles on meshes of the filter screen, so that the filter screen is blocked and loses the filtering function. In the scheme, the screen column 14 is fully closed, but the round side surface and two round end surfaces of the screen column 14 are densely provided with meshes, in the device, the hydraulic rod 15 drives the screen column 14 to move in the round sleeve 13, so that the round side surface of the screen column 14 can be continuously scraped and ground by the round sleeve 13, solid particles cannot be accumulated on the round side surface of the screen column 14, and liquid energy in the reaction tank 1 can be ensured to continuously enter the round sleeve 13 through the screen column 14 and then leave the round sleeve 13 from a guide pipe on the round sleeve 13.

As shown in fig. 1 and 8, the reaction kettle further comprises a cooling reflux device, the cooling reflux device is installed at the tank top 102 of the reaction tank 1, and the cooling reflux device is used for refluxing the evaporated reaction liquid; the cooling reflux device comprises an inner pipe 16 and an outer pipe 17, the inner pipe 16 is arranged in the outer pipe 17, two pipe orifices of the inner pipe 16 are both positioned outside the outer pipe 17, and the inner pipe 16 is used for introducing cooling liquid; one nozzle of the outer tube 17 is communicated with the reaction tank 1, the other nozzle of the outer tube 17 is closed, and a plurality of semiconductor thermoelectric materials 18 are arranged on the wall of the outer tube 17.

The conventional condenser pipe is provided with an inner pipe 16 for backflow, and cold water is introduced into a gap between the inner pipe 16 and an outer pipe 17, so that the condensing efficiency of the condenser pipe is low. In the above-described cooling reflux apparatus, the cooling liquid (usually water) is circulated through the inner tube 16, and the gap between the inner tube 16 and the outer tube 17 is used for reflux; meanwhile, the semiconductor thermoelectric material 18 is arranged on the wall of the outer tube 17, and because a great temperature difference exists between the inside and the outside of the outer tube 17, the temperature difference can be used for generating electricity, so the semiconductor thermoelectric material 18 (in a block shape) is arranged on the wall of the outer tube 17. Because one part of the heat of the reflux is transferred to the cooling liquid and the other part is converted into electric energy, the cooling reflux efficiency is higher and the reflux speed is higher. Specifically, both orifices of the inner tube 16 are outside the outer tube 17, and are designed to allow cooling water to smoothly enter the inner tube 16.

As shown in accompanying drawings 1 and 9, still include adsorption tube 19 and

liquefaction jar

20, 19 one end of adsorption tube meets with retort 1, the 19 other end of adsorption tube meets with

liquefaction jar

20, 19 intussuseptions of adsorption tube are filled with a plurality of cotton plugs that are stained with water, and be provided with the one-way device that switches on in the adsorption tube 19, the one-way device that switches on is used for guaranteeing that gaseous by 19 one-way flow direction liquefaction jar 20 of adsorption tube, be provided with a plurality of PET membrane bags 21 in the liquefaction jar 20, and PET membrane bag 21 is in the same place with the jar wall seal-match of liquefaction jar 20, and the sack of PET membrane bag 21 is located outside liquefaction jar 20.

Because the inert solvent needs to be evaporated to dryness before the decompression separation operation is carried out, 3 inert solvents (only one of the solvents is selected) can be used in the production process, namely, o-dichlorobenzene, chlorobenzene and benzonitrile, and a certain amount of hydrogen chloride gas is generated in the process of evaporating the inert solvent, so hydrogen chloride is treated, a cotton plug stained with water is filled in the adsorption pipe 19, the hydrogen chloride gas is very easy to dissolve in water, and the hydrogen chloride gas can be adsorbed by water when passing through the cotton plug, and because the adsorption pipe 19 is provided with a one-way conduction device (namely, a one-way valve, which belongs to the prior art), the gas in the adsorption pipe 19 only flows into the liquefaction tank 20, and the gas in the liquefaction tank 20 does not flow into the adsorption pipe 19. When the gas in the adsorption pipe 19 continuously enters the liquefaction tank 20, low-temperature water (lower than 25 ℃) is filled into the PET film bag 21, the low-temperature water source continuously flushes into the PET film bag, the PET film bag 21 expands, the space in the liquefaction tank 20 is reduced, certain extrusion effect on inert solvent steam in the liquefaction tank 20 is achieved, and meanwhile, due to the fact that water in the PET film bag 21 has a good cooling effect, under the combined action of high-pressure water and low-temperature water, inert solvent steam in the liquefaction tank 20 can be liquefied quickly, and the inert solvent steam can be further recycled after liquefaction. A specific mounting method may be to open the liquefaction tank 20 and then to glue the PET film bag 21 to the opening of the liquefaction tank 20 by means of glue.

The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings can be directly or indirectly applied to other related technical fields and are included in the scope of the present invention.

Claims

1. A method for preparing methylcyclohexyl diisocyanate based on reduced pressure fractionation is characterized by comprising the following steps:

s1: using methylcyclohexyl diamine or methylcyclohexyl diamine salt or a mixture of the methylcyclohexyl diamine and the methylcyclohexyl diamine salt as a first preparation raw material, using bis (trichloromethyl) carbonate or trichloromethyl chloroformate or a mixture of the trichloromethyl chloroformate and the trichloromethyl chloroformate as a second preparation raw material, and mixing the first preparation raw material and the second preparation raw material in an inert solvent;

s2: maintaining the mixture of the first preparation raw material and the second preparation raw material at 0-70 ℃ for reaction for 0-4 h, and raising the reaction temperature to 100-170 ℃ for reaction for 0-4 h;

s3: carrying out reduced pressure fractionation on the reaction product prepared in the step S2;

the steps S1, S2 and S3 are all carried out in a methyl cyclohexyl diisocyanate preparation reaction kettle,

the methyl cyclohexyl diisocyanate preparation reaction kettle comprises a reaction tank, a plurality of permanent magnets and a plurality of electromagnet assemblies, plastic balls and a plurality of blades; the copper bar is fixedly arranged at the bottom of the reaction tank, the bottom of the reaction tank is made of a non-ferrous material, the permanent magnet is fixedly arranged in the plastic ball, the plastic ball is provided with a through hole, the plastic ball is sleeved on the copper bar in a sliding manner through the through hole, and the blades are arranged on the outer wall of the plastic ball; a spiral groove is formed in the outer wall of the copper rod, a sliding ball is fixedly arranged on the plastic ball, and the sliding ball is located in the spiral groove; the electromagnet assembly is movably or fixedly arranged outside the reaction tank, the copper bar and the electromagnet assembly are respectively positioned on two sides of the bottom of the tank, and the electromagnet assembly is used for driving the plastic balls to rotate and move along the copper bar; the plastic balls are polyphenylene sulfide plastic balls or polysulfone plastic balls, and the sliding beads are polyphenylene sulfide sliding beads or polysulfone plastic sliding beads; the copper bar is a hollow copper bar, the copper bar and the copper bar are hermetically communicated together through a heat conduction pipe, and the copper bar and the heat conduction pipe are used for circulating steam;

the methyl cyclohexyl diisocyanate preparation reaction kettle further comprises a non-ferrous sleeve and a non-ferrous impact roller; the sleeve is arranged at the tank top of the reaction tank, the tank top is made of nonferrous materials, one opening of the sleeve is fixedly connected with the feed inlet of the reaction tank, and the other opening of the sleeve is positioned in the reaction tank; the impact roller is movably arranged in the sleeve, a round sliding column is arranged on the outer wall surface of the impact roller, a circular arc-shaped slide way penetrating through the wall of the sleeve is formed in the sleeve, the round sliding column is located in the slide way, and the slide way and the round sliding column are matched with each other to prevent the impact roller from falling from the sleeve; an iron block is arranged in the impact roller, a plurality of groups of electromagnet assemblies are arranged at the peripheral edge of the outer cylinder wall of the sleeve, the electromagnet assemblies on the sleeve are used for driving the impact roller to move in the sleeve, and a gap between the sleeve and the impact roller is a passage for solid particle raw materials to enter the reaction tank; a cylindrical spring is sleeved on the round sliding column, one end of the cylindrical spring is fixed on the outer wall of the impact roller, and the cylindrical spring is used for organizing the impact roller to directly impact the sleeve;

the reactor for preparing the methyl cyclohexyl diisocyanate further comprises a filtering device, the filtering device is hermetically arranged at a discharge port of the reaction tank, and the filtering device is used for filtering solid particle impurities in a reaction product; the filtering device comprises a round sleeve, a screen column and a hydraulic rod, wherein the outer wall of the round sleeve is hermetically matched with a discharge hole of the reaction tank through threads; the screen column is arranged in the round sleeve in a sliding mode, the outer cylinder wall of the screen column is tightly attached to the inner wall of the round sleeve, one end of the hydraulic rod is fixed on the round sleeve in a sealing mode, the other end of the hydraulic rod is fixed with the screen column together, the hydraulic rod is used for driving the screen column to move in the round sleeve, the round sleeve is connected with a guide pipe, and liquid in the round sleeve leaves the round sleeve through the guide pipe;

the methyl cyclohexyl diisocyanate preparation reaction kettle further comprises a cooling reflux device, the cooling reflux device is installed at the top of the reaction tank, and the cooling reflux device is used for refluxing the evaporated reaction liquid; the cooling reflux device comprises an inner pipe and an outer pipe, the inner pipe is arranged in the outer pipe, two pipe orifices of the inner pipe are both positioned outside the outer pipe, and the inner pipe is used for introducing cooling liquid; one pipe orifice of the outer pipe is communicated with the reaction tank, the other pipe orifice of the outer pipe is closed, and a plurality of semiconductor thermoelectric materials are arranged on the pipe wall of the outer pipe; the methyl cyclohexyl diisocyanate preparation reaction kettle further comprises a telescopic rod and a hose; the telescopic rod is a pneumatic telescopic rod or a hydraulic telescopic rod, one end of the telescopic rod is fixed at the tank top of the reaction tank, and the other end of the telescopic rod is fixed with a temperature probe which is used for detecting the temperature of liquid in the tank; one pipe orifice of the hose is fixed on the telescopic rod and is positioned near the temperature probe, the other pipe orifice of the hose is positioned outside the reaction tank, and a gap between the hose and the tank wall of the reaction tank is coated with a sealant; the methyl cyclohexyl diisocyanate preparation reaction kettle further comprises a plurality of ball springs, the ball springs are made of nonferrous materials and fixedly sleeved on the copper rod, and the ball springs are respectively positioned on two sides of the plastic ball.

2. The method for preparing methylcyclohexyl diisocyanate based on vacuum fractionation as claimed in claim 1, wherein the methylcyclohexyl diisocyanate preparation reaction kettle further comprises an adsorption tube and a liquefaction tank, one end of the adsorption tube is connected to the reaction tank, the other end of the adsorption tube is connected to the liquefaction tank, a plurality of cotton plugs soaked with water are filled in the adsorption tube, a one-way conduction device is arranged in the adsorption tube, the one-way conduction device is used for ensuring that gas flows from the adsorption tube to the liquefaction tank in a one-way manner, a plurality of PET film bags are arranged in the liquefaction tank, the PET film bags are hermetically matched with the tank wall of the liquefaction tank, and the bag opening of the PET film bag is located outside the liquefaction tank.