Continuous flow reactor for synthesizing tetrabutylurea

Abstract

The utility model provides a continuous flow reactor for synthesis of tetrabutylurea, which comprises a reactor body, an upper mixing zone, a reaction zone and a lower mixing zone are arranged in the reactor body in a separating manner, and the reactor body is provided with a tetrabutylurea discharge port, a phosgene feed port, a liquid caustic soda feed port and a di-n-butylamine feed port. A gas distribution plate is arranged in the lower mixing area to divide the lower mixing area into a lower material distribution area and a discharging area, annular phosgene gas distribution pipes are distributed on the gas distribution plate, the phosgene feeding port is connected with the phosgene gas distribution pipes, and a tetrabutyl urea discharging channel is formed in the lower partition plate; phosgene one-way inlet valves are distributed on a bottom plate of the lower partition plate; a material distribution plate is arranged in the upper mixing area to divide the upper mixing area into an upper material distribution area and an upper mixing area, a liquid caustic soda material distribution pipeline and a di-n-butylamine material distribution pipeline are distributed on the material distribution plate, and a plurality of mixed feeding holes are distributed in an upper partition plate; the temperature rise of phosgene is converted into a gas phase from a liquid phase, the phosgene reacts with di-n-butylamine, the di-n-butylamine moves from top to bottom, and the continuous flow reaction can improve the utilization rate of raw materials and increase the yield.

Description

Technical Field

[0001] The utility model relates to the technical field related to chemical production, in particular to a continuous flow reactor for synthesizing tetrabutyl urea. Background Art

[0002] Tetrabutyl urea is a chemical substance that is a transparent or slightly yellowish liquid with a viscosity slightly greater than that of water. It is mainly used as a hydroanthraquinone solvent in the new process of producing hydrogen peroxide by the anthraquinone method.

[0003] The preparation method of tetrabutyl urea can be divided into phosgene method and non-phosgene method. The non-phosgene method is not competitive in industrial equipment due to the disadvantages of more by-products, low yield and high cost. The phosgene method includes solid phosgene method, diphosgene method and single phosgene method. In the preparation process using triphosgene and diphosgene methods, it is necessary to add a large amount of catalyst at the reaction stage, while using single phosgene method, it is only necessary to extract some residual products in the aqueous phase with an organic solvent after the reaction is completed, and the amount of solvent used is greatly reduced. Among them, patent documents CN102702029A and CN108203400A provide the process of preparing tetrabutyl urea in batches using a batch reactor using single phosgene, which has a low space-time yield. CN1668582A provides a method for continuously preparing tetrasubstituted urea, but adopts traditional two-stage series reactor operation. Due to the low water solubility of the raw material phosgene, the phosgene yield is low and the reaction residence time is long.

[0004] Furthermore, existing phosgene-based reactors typically directly add liquid caustic soda and di-n-butylamine to the reactor, followed by an organic solvent. Phosgene is then introduced into the reactor and heated for reaction. This requires an excessive amount of phosgene to be introduced, and a large amount of unreacted phosgene is discharged through the tail gas outlet, resulting in high tail gas treatment costs. Furthermore, this reaction method is limited to a batch reaction and cannot achieve continuous reaction. Utility Model Content

[0005] The utility model aims to provide a continuous flow reactor for tetrabutylurea synthesis, which can continuously prepare tetrabutylurea, and reaction raw materials enter from the upper and lower ends respectively, which can continuously react and improve the utilization rate of raw materials.

[0006] To this end, the technical solution adopted by the present invention is: a continuous flow reactor for tetrabutyl urea synthesis, comprising a reactor body, wherein the reactor body is separated from top to bottom into an upper mixing zone, a reaction zone and a lower mixing zone by an upper baffle and a lower baffle respectively located at the upper and lower parts, wherein a heating jacket is provided outside the reaction zone, a tetrabutyl urea discharge port and a liquid phase phosgene feed port are provided at the bottom end of the reactor body, a liquid alkali feed port and a di-n-butylamine feed port are provided at the top, an air distribution plate is horizontally provided in the middle of the lower mixing zone, the air distribution plate divides the lower mixing zone from top to bottom into a lower distribution zone and a discharge zone, the discharge zone is connected to the tetrabutyl urea discharge port, an annular phosgene distribution pipe is distributed on the air distribution plate, and the phosgene feed port is passed through The pipeline passing through the discharge zone is directly connected to the phosgene distribution pipe, and phosgene atomizing nozzles are distributed on the phosgene distribution pipe. A tetrabutyl urea discharge channel is provided on the lower partition, and the tetrabutyl urea discharge channel is directly connected to the discharge zone through the distribution plate; a number of phosgene one-way air inlet valves are distributed on the bottom plate of the lower partition; a distribution plate is horizontally provided in the middle of the upper mixing zone, and the distribution plate divides the upper mixing zone from top to bottom into an upper distribution zone and an upper mixing zone, and an annular liquid alkali distribution pipe and an annular di-n-butylamine distribution pipe are distributed on the distribution plate, and the annular liquid alkali distribution pipe and the annular di-n-butylamine distribution pipe are directly connected to the liquid alkali feed port and the di-n-butylamine feed port respectively through pipes, and a number of mixed feed ports are distributed on the upper partition.

[0007] As a preferred embodiment of the above scheme, the annular liquid alkali distribution pipe and the annular di-n-butylamine distribution pipe are respectively evenly distributed with liquid alkali discharge nozzles and di-n-butylamine discharge nozzles, and the annular liquid alkali distribution pipe and the annular di-n-butylamine distribution pipe are spaced apart from the inside to the outside on the distribution plate.

[0008] More preferably, there are three annular liquid caustic soda distribution pipes and three annular di-n-butylamine distribution pipes.

[0009] Further preferably, the phosgene distribution pipes are annular pipes, and there are three of them, which are coaxially arranged on the distribution plate from the inside to the outside. The tetrabutyl urea discharge channels are distributed between two adjacent phosgene distribution pipes and in the middle of the central phosgene distribution pipe. The tetrabutyl urea discharge channels are distributed in an annular array on the lower partition plate.

[0010] More preferably, the reaction zone is divided into at least two annular reaction zones from inside to outside by an annular partition.

[0011] More preferably, the bottom of the heating jacket is provided with a medium inlet, and the top is provided with a medium outlet.

[0012] More preferably, a safety valve is provided at the top of the reactor body, and the safety valve is connected to the tail gas treatment system.

[0013] The reactants of the present invention are di-n-butylamine and phosgene, and a liquid caustic soda aqueous solution is used as a catalyst. The liquid caustic soda and di-n-butylamine are distributed through their respective distribution pipes and mixed in the upper mixing zone, then enter the reaction zone through the mixing air inlet, flowing from top to bottom. Liquid phosgene enters the phosgene distribution pipe through the phosgene feed port, is atomized by the atomizing nozzle to form phosgene (phosgene has a very low boiling point), enters the reaction zone from bottom to top, and comes into countercurrent contact with the mixture of liquid caustic soda and di-n-butylamine to react. The air distribution plate allows phosgene to enter various positions in the reaction zone more evenly, allowing phosgene to uniformly contact and react with the mixture of di-n-butylamine and liquid caustic soda. The ascending phosgene is continuously captured by the descending di-n-butylamine and liquid caustic soda, thereby improving the utilization rate of phosgene, di-n-butylamine, and liquid caustic soda, and phosgene is almost never discharged from the reactor. The tetrabutyl urea obtained after the reaction is completed enters the discharge zone through the tetrabutyl urea discharge channel, and is then discharged for the next step of processing.

[0014] The beneficial effects of the utility model are as follows: liquid phosgene enters the interior of the reactor body from the lower end, and liquid di-n-butylamine enters the interior of the reactor body from the upper end to react with the phosgene; after entering the reactor body, the temperature of the phosgene rises and it is converted from the liquid phase to the gas phase; the upward phosgene is continuously captured by the downward di-n-butylamine and liquid caustic soda, thereby improving the utilization rate of the phosgene, di-n-butylamine and liquid caustic soda and increasing the output. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural diagram of embodiment 1 of the present utility model.

[0016] Figure 2 yes Figure 1 Cross-section at BB.

[0017] Figure 3 yes Figure 1 Cross-sectional view at CC.

[0018] Figure 4 This is a schematic diagram of the structure of the second embodiment of the present invention

[0019] Figure 5 yes Figure 4 Cross-section at AA in the middle. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Example 1:

[0022] like Figure 1-4As shown, a continuous flow reactor for tetrabutyl urea synthesis includes a reactor body 1, which has a circular cross-section and is provided with an inspection manhole. The reactor body 1 is separated from the top to the bottom by an upper partition 2 and a lower partition 3 located at the upper and lower parts, respectively, into an upper mixing zone 10, a reaction zone 4, and a lower mixing zone. A heating jacket 12 is provided outside the reaction zone 4. The bottom end of the reactor body 1 is provided with a tetrabutyl urea discharge port 5 and a liquid phosgene feed port 6. The top end is provided with a liquid caustic soda feed port 7 and a di-n-butylamine feed port 8. A gas distribution plate is provided horizontally in the middle of the lower mixing zone. The gas distribution plate divides the lower mixing zone from top to bottom into a lower distribution zone 9 and a discharge zone 15. The discharge zone 15 is connected to the tetrabutyl urea discharge port 5. An annular phosgene distribution pipe 601 is distributed on the gas distribution plate. The phosgene feed port 6 is directly connected to the phosgene distribution pipe 601 through a pipe passing through the discharge zone 15. The phosgene distribution pipe 601 is connected to the phosgene distribution pipe 601. 1 is provided with a phosgene atomizing nozzle 602, and a tetrabutyl urea discharge channel 501 is provided on the lower partition 3. The tetrabutyl urea discharge channel 501 passes through the gas distribution plate and is directly connected to the discharge area 15; a plurality of phosgene one-way air inlet valves 603 are distributed on the bottom plate of the lower partition 3; a distribution plate is horizontally provided in the middle of the upper mixing area 10, and the distribution plate divides the upper mixing area 10 from top to bottom into an upper distribution area 11 and an upper mixing area 10, and an annular liquid caustic soda distribution pipe 701 and an annular di-n-butylamine distribution pipe 801 are distributed on the distribution plate. The annular liquid caustic soda distribution pipe 701 and the annular di-n-butylamine distribution pipe 801 are directly connected to the liquid caustic soda feed port 7 and the di-n-butylamine feed port 8 respectively through pipes. A plurality of mixed feed ports 14 are distributed on the upper partition 2.

[0023] The annular liquid alkali distribution pipe 701 and the annular di-n-butylamine distribution pipe 801 are respectively evenly distributed with liquid alkali discharge nozzles 702 and di-n-butylamine discharge nozzles 802. The annular liquid alkali distribution pipe 701 and the annular di-n-butylamine distribution pipe 801 are spaced apart from the inside to the outside on the distribution plate.

[0024] There are three annular caustic soda distribution pipes 701 and three annular di-n-butylamine distribution pipes 801. The three caustic soda distribution pipes and di-n-butylamine distribution pipes ensure that the caustic soda and di-n-butylamine are fully mixed before entering the reaction zone.

[0025] The phosgene distribution pipes 601 are annular pipes, and there are three of them, which are coaxially arranged on the distribution plate from the inside to the outside. Tetrabutyl urea discharge channels 501 are distributed between two adjacent phosgene distribution pipes 601 and in the middle of the central phosgene distribution pipe 601. The tetrabutyl urea discharge channels 501 are distributed in an annular array on the lower partition plate 3.

[0026] The heating jacket 12 is provided with a medium inlet at the bottom and a medium outlet at the top. The medium inlet of the heating jacket 12 is provided at the bottom, and the medium outlet is provided at the top, to ensure the normal progress of the reaction and to quickly convert phosgene from the liquid phase to the gas phase, thereby improving the efficiency of subsequent reactions and increasing the utilization rate of phosgene.

[0027] A safety valve 13 is also provided at the top of the reactor body 1, and the safety valve 13 is connected to the tail gas treatment system. The safety valve is provided so that phosgene is discharged from the safety valve when an abnormal reaction occurs.

[0028] Example 2:

[0029] Combine Figure 4 As shown, the rest is the same as that of Example 1, except that the reaction zone 4 is divided into three annular reaction zones 4 from the inside to the outside by an annular partition 16. The reaction zone 4 includes a first reaction zone 401, a second reaction zone 402, and a third reaction zone 403. The provision of the first reaction zone 401, the second reaction zone 402, and the third reaction zone 403 facilitates sufficient contact and reaction between phosgene and di-n-butylamine, thereby improving the utilization rate of raw materials and productivity. However, there may be a problem of uneven temperature.

[0030] Liquid phosgene enters the interior of the reactor body 1 from the lower end, and liquid di-n-butylamine enters the interior of the reactor body 1 from the upper end to react with the phosgene. After entering the reactor body 1, the temperature of the phosgene increases and it is converted from the liquid phase to the gas phase. The upward phosgene is continuously captured by the downward di-n-butylamine and liquid caustic soda, thereby improving the utilization rate of phosgene, di-n-butylamine and liquid caustic soda and increasing the yield.

[0031] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A continuous flow reactor for tetrabutylurea synthesis, characterized in that: The reactor body (1) comprises an upper mixing zone (10), a reaction zone (4) and a lower mixing zone, which are separated from top to bottom by an upper baffle (2) and a lower baffle (3) located at the upper and lower parts respectively, wherein a heating jacket (12) is provided outside the reaction zone (4), a tetrabutylurea discharge port (5) and a liquid phosgene feed port (6) are provided at the bottom of the reactor body (1), and a liquid alkali feed port (7) is provided at the top. ) and a di-n-butylamine feed port (8), an air distribution plate is horizontally arranged in the middle of the lower mixing zone, and the air distribution plate divides the lower mixing zone into a lower distribution zone (9) and a discharge zone (15) from top to bottom, and the discharge zone (15) is connected to the tetrabutyl urea discharge port (5). An annular phosgene distribution pipe (601) is distributed on the air distribution plate, and the phosgene feed port (6) is directly connected to the phosgene distribution pipe (601) through a pipeline passing through the discharge zone (15). A phosgene atomizing nozzle (602) is distributed on the air pipe (601), and a tetrabutyl urea discharge channel (501) is provided on the lower partition (3), and the tetrabutyl urea discharge channel (501) is directly connected to the discharge area (15) through the air distribution plate; a plurality of phosgene one-way air inlet valves (603) are distributed on the bottom plate of the lower partition (3); a distribution plate is horizontally provided in the middle of the upper mixing area (10), and the distribution plate distributes the upper mixing area (10) from the upper The lower partition is set as an upper distribution area (11) and an upper mixing area (10). An annular liquid caustic soda distribution pipe (701) and an annular di-n-butylamine distribution pipe (801) are distributed on the distribution plate. The annular liquid caustic soda distribution pipe (701) and the annular di-n-butylamine distribution pipe (801) are directly connected to the liquid caustic soda feed port (7) and the di-n-butylamine feed port (8) through pipes respectively. A plurality of mixing feed ports (14) are distributed on the upper partition (2).

2. A continuous flow reactor for tetrabutylurea synthesis according to claim 1, characterized in that: The annular liquid caustic soda distribution pipe (701) and the annular di-n-butylamine distribution pipe (801) are respectively uniformly provided with liquid caustic soda discharge nozzles (702) and di-n-butylamine discharge nozzles (802). The annular liquid caustic soda distribution pipe (701) and the annular di-n-butylamine distribution pipe (801) are spaced apart from the inside to the outside on the distribution plate.

3. A continuous flow reactor for tetrabutylurea synthesis according to claim 2, characterized in that: There are three annular liquid caustic soda distribution pipes (701) and three annular di-n-butylamine distribution pipes (801).

4. A continuous flow reactor for tetrabutylurea synthesis according to any one of claims 2 to 3, characterized in that: The phosgene distribution pipes (601) are annular pipes, and there are three of them. They are coaxially arranged on the distribution plate from the inside to the outside. The tetrabutyl urea discharge channels (501) are distributed between two adjacent phosgene distribution pipes (601) and in the middle of the central phosgene distribution pipe (601). The tetrabutyl urea discharge channels (501) are distributed in an annular array on the lower partition plate (3), which is conducive to the uniform dispersion of phosgene.

5. A continuous flow reactor for tetrabutylurea synthesis according to claim 1, characterized in that: The reaction zone (4) is divided into at least two annular reaction zones (4) from the inside to the outside by an annular partition (16).

6. A continuous flow reactor for tetrabutylurea synthesis according to claim 1, characterized in that: The bottom of the heating jacket (12) is provided with a medium inlet, and the top is provided with a medium outlet.

7. A continuous flow reactor for tetrabutylurea synthesis according to claim 1, characterized in that: A safety valve (13) is also provided at the top of the reactor body (1), and the safety valve (13) is connected to the tail gas treatment system.

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