Method for continuously preparing tert-butyl isocyanate

Abstract

The invention discloses a method for continuously preparing tert-butyl isocyanate, and relates to the technical field of tert-butyl isocyanate, and the method comprises the following steps: mixing an inert solvent and p-toluene sulfonamide, introducing phosgene, and introducing inert gas to expel gas after the reaction to obtain a first reaction solution; dropwise adding tert-butylamine into the first reaction solution, and heating and refluxing for more than 4 hours to obtain a second reaction solution; performing separation and purification on the second reaction liquid through separation and purification equipment to obtain tert-butyl isocyanate; the separation and purification equipment comprises a water bath kettle, wherein liquid outlet pipes are respectively arranged at the upper ends of two side walls; the liquid inlet box is arranged in the water bath kettle, a plurality of liquid spraying pipes and a liquid inlet pipe are arranged on the liquid inlet box, and the liquid inlet pipe penetrates through the kettle wall of the water bath kettle; the first evaporation assembly or the second evaporation assembly is arranged in the water bath kettle; the device has the advantages of being convenient to use, improving the purification efficiency and effect and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tert-butyl isocyanate, in particular to a method for continuously preparing tert-butyl isocyanate. BACKGROUND

[0002] In the production and processing process of tert-butyl isocyanate, the tert-butyl isocyanate needs to be purified in the last step of production. For example, patent application No. CN202411467931.2 discloses a purification method and intelligent purification device for tert-butyl isocyanate. The existing purification method in this patent is mainly through water bath purification. In the purification process, the rotation of the rotating bottle realizes uniform heating. However, in the process of rotation, the rotating bottle and the liquid in the bottle will rotate relatively, so the heating of the liquid in the bottle cannot be uniform. Therefore, in the actual purification process, the purity of the purified product is low and the efficiency is low. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a method for continuously preparing tert-butyl isocyanate to solve the problem of poor effect and low efficiency of the existing purification method of tert-butyl isocyanate described in the background.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical solution: a method for continuously preparing tert-butyl isocyanate, comprising the following steps:

[0005] Mixing inert solvent and p-toluenesulfonamide, introducing phosgene, and then purging with inert gas after the reaction is complete to obtain a first reaction liquid; adding tert-butylamine dropwise to the first reaction liquid and heating to reflux for more than 4 hours to obtain a second reaction liquid; separating and purifying the second reaction liquid by a separation and purification device to obtain tert-butyl isocyanate;

[0006] The separation and purification device comprises

[0007] A water bath kettle, the upper ends of the two side walls are respectively provided with liquid outlet pipes;

[0008] A liquid inlet box is arranged in the water bath kettle, a plurality of liquid injection pipes and a liquid inlet pipe are arranged on the liquid inlet box, and the liquid inlet pipe penetrates the kettle wall of the water bath kettle;

[0009] A first evaporation assembly or a second evaporation assembly is arranged in the water bath kettle;

[0010] The first evaporation assembly comprises

[0011] A first evaporation pipe is located in the water bath kettle;

[0012] A first feeding pipe penetrates the upper end wall of the water bath kettle and the upper end wall of the first evaporation pipe;

[0013] two first discharge pipes, one end of each of which penetrates the side wall of the water bath and is connected to the side wall of the first evaporation pipe, the first discharge pipes being in communication with the first evaporation pipe, and the first feed pipe being located between the two first discharge pipes;

[0014] a plurality of first steam pipes, one end of each of which penetrates the upper end wall of the water bath and is connected to the upper end wall of the first evaporation pipe, the first steam pipes being in communication with the first evaporation pipe;

[0015] the second evaporation assembly comprises

[0016] a second evaporation pipe and a third evaporation pipe, each of which is located in the water bath and is flat;

[0017] a second feed pipe, one end of which is arranged on one side wall of the second evaporation pipe and is in communication with the second evaporation pipe, and the other end of which penetrates the upper end wall of the water bath;

[0018] a connecting pipe, two ends of which are in communication with the second evaporation pipe and the third evaporation pipe, respectively;

[0019] a second discharge pipe, one end of which is in communication with the side wall of the third evaporation pipe, and the other end of which penetrates the side wall of the water bath;

[0020] a third partition plate, which is arranged on the bottom inner wall of the second evaporation pipe and is opposite the second feed pipe;

[0021] a fourth partition plate, which is arranged on the bottom inner wall of the third evaporation pipe and is opposite the connecting pipe;

[0022] a plurality of second steam pipes, one end of each of which is arranged on the upper end wall of the second evaporation pipe and is in communication with the second evaporation pipe, and the other end of each of which penetrates the upper end wall of the water bath;

[0023] a plurality of third steam pipes, one end of each of which is arranged on the upper end wall of the third evaporation pipe and is in communication with the third evaporation pipe, and the other end of each of which penetrates the side wall of the water bath in an upwardly inclined manner.

[0024] Preferably, the first evaporation pipe is in the shape of a triangular prism, and the liquid injection pipe is opposite the lower prism.

[0025] Preferably, the bottom inner wall of the first evaporation pipe is provided with first partition plates at positions corresponding to the pipe openings of the two first discharge pipes, the first partition plates are in contact with the front and rear inner walls of the first evaporation pipe, and the first feed pipe is located between the two first partition plates.

[0026] Preferably, the first evaporation pipe is provided with two second partition plates, the second partition plates are connected to the front and rear inner walls of the first evaporation pipe, the two second partition plates are located between the first partition plates and the first steam pipes, respectively, gaps are respectively left between the upper and lower end inner walls of the first evaporation pipe and the second partition plates, and the horizontal height of the lower end wall of the second partition plate is lower than the horizontal height of the upper end wall of the first partition plate.

[0027] Preferably, the first evaporation pipe is provided with several through pipes penetrating the first evaporation pipe.

[0028] Preferably, the first outlet pipe penetrates a first through hole on the upper end wall of the water bath, the outer wall of the first outlet pipe is seamlessly sleeved with a first soft sleeve, the first soft sleeve is seamlessly connected with the first through hole; the first steam pipe penetrates a third through hole on the upper end wall of the water bath, the outer wall of the first steam pipe is seamlessly sleeved with a third soft sleeve, the third soft sleeve is seamlessly connected with the third through hole; the first inlet pipe penetrates a second through hole on the upper end wall of the water bath, the outer wall of the first inlet pipe is seamlessly sleeved with a second soft sleeve, the second soft sleeve is seamlessly connected with the second through hole; the outer wall of the first evaporation pipe is provided with two vibration plates, the vibration plates penetrate a fourth through hole on the upper end wall of the water bath, the outer wall of the vibration plates is seamlessly sleeved with a fourth soft sleeve, the fourth soft sleeve is seamlessly connected with the fourth through hole, one end of the vibration plates extending out of the water bath is provided with a vibrator, the outer wall of the water bath is provided with a support plate at the position corresponding to the vibration plates, the support plate and the vibration plates are connected through a plurality of damping springs.

[0029] The beneficial effects of the above technical solutions are:

[0030] By adopting the first evaporation assembly, the raw materials can be introduced into the center of the first evaporation pipe through the first inlet pipe, then spread to both ends, evaporate and flow in the process of spreading, and the liquid injection pipe on the liquid inlet box can spray on the first evaporation pipe to realize uniform heating, improve the efficiency and effect of purification, and the first evaporation pipe can be vibrated by the vibrator to improve the flow of the raw materials in the first evaporation pipe;

[0031] By adopting the second evaporation assembly, the thickness of the raw materials can be reduced through the flat second evaporation pipe and the third evaporation pipe, so that the evaporation efficiency and effect are improved. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a sectional view of the separation and purification equipment of the present application.

[0033] Figure 2 is a sectional view of the first evaporation pipe of the present application.

[0034] Figure 3 is a schematic view of the first evaporation pipe of the present application.

[0035] Figure 4 is a schematic view of the first evaporation pipe of the present application.

[0036] Figure 5 is a side view of the water bath containing the first evaporation pipe of the present application.

[0037] Figure 6is a sectional view of the first evaporation pipe of the present application which can vibrate.

[0038] Figure 7 is a schematic view of the water bath kettle of the present application with the first evaporation pipe which can vibrate.

[0039] Figure 8 is a schematic view of the water bath kettle of the present application with the second evaporation assembly. Figure 7

[0040] Figure 9 is a sectional view of the second evaporation assembly of the present application.

[0041] Figure 10 is a sectional view of the second evaporation assembly of the present application.

[0042] Figure 11 is a schematic view of the third steam pipe of the present application.

[0043] Wherein: the water bath kettle 100, the liquid outlet pipe 110, the liquid inlet box 200, the liquid spray pipe 210, the liquid inlet pipe 220, the first evaporation pipe 300, the first partition plate 301, the second partition plate 302, the first discharge pipe 310, the first through hole 311, the first soft sleeve 312, the first feed pipe 320, the second through hole 321, the second soft sleeve 322, the through pipe 330, the second evaporation pipe 340, the third partition plate 341, the second feed pipe 342, the connecting pipe 343, the third evaporation pipe 350, the fourth partition plate 351, the second discharge pipe 352, the first steam pipe 400, the third through hole 401, the third soft sleeve 402, the second steam pipe 410, the gas collecting pipe 411, the third steam pipe 420, the vibration plate 500, the fourth through hole 501, the fourth soft sleeve 502, the damping spring 510, the support plate 520, the vibrator 530. DETAILED DESCRIPTION

[0044] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0045] A method for continuously preparing tert-butyl isocyanate, comprising the following steps:

[0046] Mixing inert solvent and p-toluene sulfonamide, introducing phosgene, passing inert gas to chase gas after reaction, obtaining first reaction liquid; adding tert-butyl amine dropwise to the first reaction liquid, heating to reflux for more than 4 hours, obtaining second reaction liquid; separating and purifying the second reaction liquid by separation and purification equipment, obtaining tert-butyl isocyanate;

[0047] The separation and purification equipment comprises

[0048] The water bath kettle 100 is provided with a liquid outlet pipe 100 at the upper end of each side wall.

[0049] ​The liquid inlet box 200 is arranged in the water bath pot 100, and a plurality of liquid spraying pipes 210 and a liquid inlet pipe 220 are arranged on the liquid inlet box 200, and the liquid inlet pipe 220 penetrates the pot wall of the water bath pot 100;

[0050] The first evaporation assembly or the second evaporation assembly is arranged in the water bath pot;

[0051] The first evaporation assembly comprises

[0052] The first evaporation pipe 300 is located in the water bath pot 100;

[0053] The first feeding pipe 320 penetrates the upper end wall of the water bath pot 100 and the upper end wall of the first evaporation pipe 300 at one end;

[0054] The two first discharging pipes 310 penetrate the side wall of the water bath pot 100 at one end and are connected to the side wall of the first evaporation pipe 300, the first discharging pipe 310 communicates with the first evaporation pipe 300, and the first feeding pipe 320 is located between the two first discharging pipes 310;

[0055] The plurality of first steam pipes 400 penetrate the upper end wall of the water bath pot 100 at one end and are connected to the upper end wall of the first evaporation pipe 300, and the first steam pipe 400 communicates with the first evaporation pipe 300;

[0056] The second evaporation assembly comprises

[0057] The second evaporation pipe 340 and the third evaporation pipe 350 are respectively located in the water bath pot 100, and the second evaporation pipe 340 and the third evaporation pipe 350 are both flat;

[0058] The second feeding pipe 342 is arranged on one side wall of the second evaporation pipe 340 and communicates with the second evaporation pipe 340 at one end, and penetrates the upper end wall of the water bath pot 100 at the other end;

[0059] The pipe 343 communicates with the second evaporation pipe 340 and the third evaporation pipe 350 at both ends;

[0060] The second discharging pipe 352 communicates with the side wall of the third evaporation pipe 350 at one end and penetrates the side wall of the water bath pot 100 at the other end;

[0061] The third partition plate 341 is arranged on the bottom inner wall of the second evaporation pipe 340 and opposite to the position of the second feeding pipe 341;

[0062] The fourth partition plate 351 is arranged on the bottom inner wall of the third evaporation pipe 350 and opposite to the position of the pipe 343;

[0063] The plurality of second steam pipes 410 are respectively arranged on the upper end wall of the second evaporation pipe 340 and communicate with the second evaporation pipe 340 at one end, and penetrate the upper end wall of the water bath pot 100 at the other end;

[0064] Several third steam pipes 420 are arranged at one end of the upper end wall of the third evaporation pipe 350 and communicated with the third evaporation pipe 350, and the other end is inclined upward and penetrates the side wall of the water bath pot 100.

[0065] The embodiment is implemented as follows:

[0066] When the water bath pot with the first evaporation assembly is used, the raw material to be separated and purified is fed into the first evaporation pipe 300 from the first feeding pipe 320, at this time, the raw material in the first evaporation pipe 300 flows to both ends, in this process, the raw material is continuously evaporated, so that the steam flows into the first steam pipe 400 at both ends, after a period of evaporation, the pump body connected to the first discharge pipe 310 can suck the material at the bottom, the liquid injection pipe 210 on the liquid inlet box 200 uniformly sprays liquid to the bottom surface of the first evaporation pipe 300, so that the heating of the first evaporation pipe 300 is more uniform, and the efficiency and effect are higher than those of the existing water bath purification method.

[0067] When the water bath pot with the second evaporation assembly is used, the raw material to be separated and purified is fed into the second evaporation pipe 340 from the second feeding pipe 342, at this time, the raw material in the second evaporation pipe 340 flows to the direction of the connecting pipe 343, when the water level of the raw material reaches the height of the connecting pipe 343, the raw material is introduced into the third evaporation pipe 350 through the connecting pipe 343, since the second evaporation pipe 340 and the third evaporation pipe 350 of the present application are flat, the water level height of the raw material in the second evaporation pipe 340 and the third evaporation pipe 350 can be controlled, so that the raw material is heated faster and more uniformly, by arranging the third partition plate 341 and the fourth partition plate 351, the raw material discharged from the second feeding pipe 342 can be blocked, and the raw material discharged from the connecting pipe 343 can be blocked, so that the raw material stays for a longer time during the process of feeding and discharging, and the heating in the middle is small. The steam evaporated can flow out through the second steam pipe 410 and the third steam pipe 420, which is more green and efficient than the existing water bath purification method.

[0068] Please refer to Figure 4 , 5 , the first evaporation pipe 300 is a triangular prism, and the liquid injection pipe 210 is opposite to the prism directly below.

[0069] The first evaporation pipe 300 of the present application is arranged in a triangular prism shape, so that the hot water sprayed by the liquid injection pipe 210 can heat the raw material, so that the raw material is heated faster and more uniformly, and the efficiency is improved.

[0070] Please refer to Figure 1 , 2, 6, the bottom inner wall of the first evaporation pipe 300 is provided with a first partition plate 301 corresponding to the position of the two first discharge pipe 310 orifices, the first partition plate 301 is in contact with the front and rear inner walls of the first evaporation pipe 300, and the first feeding pipe 320 is located between the two first partition plates 301.

[0071] The first partition plate 301 can block the raw materials flowing out of the first feeding pipe 320, so that the purification mode of feeding and discharging from the first discharge pipe 320 at the same time can be realized.

[0072] Please refer to Figure 1 , 2 , 6, the first evaporation pipe 300 is provided with two second partition plates 302, the second partition plates 302 are connected with the front and rear inner walls of the first evaporation pipe 300, and the two second partition plates 302 are located between the first partition plate 301 and the first steam pipe 400 respectively, the second partition plates 302 are respectively left with gaps from the upper and lower end inner walls of the first evaporation pipe 300, and the horizontal height of the lower end wall of the second partition plate 302 is less than that of the upper end wall of the first partition plate 301.

[0073] The second partition plate 302 cooperates with the first partition plate 301 to make the raw materials stay in the first evaporation pipe 300 for a longer time, so that the purification mode of feeding and discharging from the first discharge pipe 320 at the same time can be realized.

[0074] Please refer to Figure 1 , 2 , 3, the first evaporation pipe 300 is provided with a plurality of through pipes 330 penetrating through the first evaporation pipe 300.

[0075] The through pipe 330 can make water pass through the through pipe 330, so as to increase the heating area of the raw materials in the first evaporation pipe 300.

[0076] Please refer to Figure 6 , 7, 8, the first discharge pipe 310 through the first water bath 100 on the upper end wall of the first hole 311, the first discharge pipe 310 of the outer wall seamless set with the first soft sleeve 412, the first soft sleeve 412 and the first hole 311 seamless connection; the first steam pipe 400 through the first water bath 100 on the upper end wall of the third hole 401, the first steam pipe 400 of the outer wall seamless set with the third soft sleeve 402, the third soft sleeve 402 and the third hole 401 seamless connection; the first feeding pipe 320 through the first water bath 100 on the upper end wall of the second hole 321, the first feeding pipe 320 of the outer wall seamless set with the second soft sleeve 322, the second soft sleeve 322 and the second hole 321 seamless connection; the outer wall of the first evaporation pipe 300 is provided with two vibration plates 500, the vibration plate 500 through the fourth hole 501 of the upper end wall of the first water bath 100, the outer wall of the vibration plate 500 is seamlessly sleeved with the fourth soft sleeve 502, and the fourth soft sleeve 502 is seamlessly connected with the fourth hole 501, and the end of the vibration plate 500 extending out of the first water bath 100 is provided with a vibrator 530, and the outer wall of the first water bath 100 is provided with a support plate 520 corresponding to the position of the vibration plate 500, and the support plate 520 is connected with the vibration plate 500 through a plurality of damping springs 510.

[0077] Through the intermittent vibration of the vibrator 530, the vibration plate 500 can be driven to vibrate, and the vibration plate 500 drives the first evaporation pipe 400 to vibrate, so that the movement range and frequency of the raw materials in the first evaporation pipe 400 are increased, so that the raw materials are heated more uniformly, and the first soft sleeve 412, the second soft sleeve 322, the third soft sleeve 402 and the fourth soft sleeve 502 in the application can play a sealing role.

[0078] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the inventive concept, a number of variations and improvements can be made, which belong to the protection scope of the present application.

Claims

1. A method for continuously preparing tert-butyl isocyanate, characterized in that: The following steps are involved: An inert solvent and p-toluenesulfonamide are mixed, phosgene is introduced, and after the reaction is complete, an inert gas is introduced to expel the gas to obtain a first reaction liquid; tert-butylamine is dropwise added to the first reaction liquid, and the mixture is heated under reflux for more than 4 hours to obtain a second reaction liquid; the second reaction liquid is separated and purified by a separation and purification device to obtain tert-butyl isocyanate; The separation and purification equipment includes The water bath has liquid outlet pipes at the upper ends of both side walls; A liquid inlet box is provided in the water bath, and is provided with a plurality of liquid spraying pipes and a liquid inlet pipe, and the liquid inlet pipe passes through the wall of the water bath; The first evaporation component or the second evaporation component is disposed in a water bath; The first evaporation component includes The first evaporation tube is located in the water bath; a first feed pipe, one end of which penetrates the upper end wall of the water bath and the upper end wall of the first evaporation tube; Two first discharge pipes, one end of which passes through the side wall of the water bath and is connected to the side wall of the first evaporation tube, the first discharge pipe is in communication with the first evaporation tube, and the first feed pipe is located between the two first discharge pipes; a plurality of first steam outlet pipes, one end of which passes through the upper end wall of the water bath and is connected to the upper end wall of the first evaporation tube, the first steam outlet pipe being in communication with the first evaporation tube; The second evaporation component includes The second evaporation tube and the third evaporation tube are respectively located in the water bath, and the second evaporation tube and the third evaporation tube are both flat; A second feed pipe, one end of which is disposed on a side wall of the second evaporation pipe and communicates with the second evaporation pipe, and the other end of which passes through the upper end wall of the water bath; A connecting pipe, with both ends connected to the second evaporation pipe and the third evaporation pipe respectively; a second discharge pipe, one end of which is connected to the side wall of the third evaporation pipe and the other end of which passes through the side wall of the water bath; a third partition plate, arranged on the bottom inner wall of the second evaporation tube and facing the second feed tube; a fourth partition plate, arranged on the inner wall of the bottom of the third evaporation tube, facing the connecting tube; a plurality of second steam outlet pipes, one end of which is respectively disposed on the upper end wall of the second evaporation pipe and communicates with the second evaporation pipe, and the other end of which passes through the upper end wall of the water bath; A plurality of third steam outlet pipes have one end each disposed on the upper end wall of the third evaporation pipe and communicated with the third evaporation pipe, and the other end inclined upward and penetrating the side wall of the water bath.

2. The method for continuously preparing tert-butyl isocyanate according to claim 1, wherein The first evaporation tube is in the shape of a triangular prism, and the liquid spraying tube is directly opposite to the prism below.

3. The method for continuously preparing tert-butyl isocyanate according to claim 1, wherein First partitions are respectively provided on the bottom inner wall of the first evaporation tube at positions corresponding to the two first discharge tube openings. The first partitions are in contact with the front and rear inner walls of the first evaporation tube. The first feed tube is located between the two first partitions.

4. The method for continuously preparing tert-butyl isocyanate according to claim 3, wherein: Two second partitions are provided in the first evaporator tube, and the second partitions are connected to the front and rear inner walls of the first evaporator tube. The two second partitions are respectively located between the first partition and the first steam outlet pipe. There is a gap between the second partition and the upper and lower inner walls of the first evaporator tube, and the horizontal height of the lower end wall of the second partition is less than the horizontal height of the upper end wall of the first partition.

5. The guiding method for the method for continuously preparing tert-butyl isocyanate according to claim 4, characterized in that: A plurality of through pipes penetrating the first evaporation tube are arranged in the first evaporation tube.

6. The method for continuously preparing tert-butyl isocyanate according to claim 5, wherein: The first discharge pipe passes through the first through hole on the upper end wall of the water bath pot, and the outer wall of the first discharge pipe is seamlessly covered with a first soft sleeve, and the first soft sleeve is seamlessly connected to the first through hole; the first steam outlet pipe passes through the third through hole on the upper end wall of the water bath pot, and the outer wall of the first steam outlet pipe is seamlessly covered with a third soft sleeve, and the third soft sleeve is seamlessly connected to the third through hole; the first feed pipe passes through the second through hole on the upper end wall of the water bath pot, and the outer wall of the first feed pipe is seamlessly covered with a second soft sleeve, and the second soft sleeve is seamlessly connected to the second through hole; two vibration plates are provided on the outer wall of the first evaporation tube, and the vibration plate passes through the fourth through hole in the upper end wall of the water bath pot, and the outer wall of the vibration plate is seamlessly covered with a fourth soft sleeve, and the fourth soft sleeve is seamlessly connected to the fourth through hole, and a vibrator is provided at one end of the vibration plate extending out of the water bath pot, and a support plate is provided on the outer wall of the water bath pot at a position corresponding to the vibration plate, and the support plate is connected to the vibration plate by a number of damping springs.

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