Alkylation reaction device and process in MEA and DEA synthesis

Abstract

The invention relates to the technical field of chemical engineering, in particular to an alkylation reaction device in MEA and DEA synthesis, the alkylation reaction device comprises a main body reaction kettle, an upper sealing cover and a lower sealing cover, the upper sealing cover and the lower sealing cover are connected to the main body reaction kettle, the upper sealing cover is provided with a motor stirrer driven by a motor to rotate, and the upper sealing cover is further provided with a feeding spray head, an upper thermometer and a pressure element; an external heating / cooling coil pipe is arranged outside the main body reaction kettle; compared with the prior art, the reactor is mainly divided into two temperature control units, firstly, the temperature of the main reaction area is controlled, and accurate and stable temperature control can be achieved; 2, the temperature of the liquid phase is independently controlled, so that the temperature fluctuation range is small when the material enters the reaction kettle to participate in the reaction, the temperature is more easily and accurately controlled, the reaction is stably carried out, and a high-purity target product is finally obtained; therefore, the internal and external independent heating / cooling temperature control systems can realize accurate temperature control of alkylation reaction, and have very strong practicability and very good application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, in particular to an alkylation reaction device and process in the synthesis of MEA and DEA. Background Art

[0002] 2-Methyl-6-ethylaniline (MEA) and 2,6-diethylaniline (DEA) are both important fine chemical organic synthesis intermediates and can be widely used in the manufacture of various fine chemical products such as pesticides, dyes, medicines and fragrances.

[0003] DEA is similar to MEA in chemical structure and plays a key role in the pesticide field, especially as an important intermediate in the production of herbicides acetochlor and butachlor. These herbicides are widely used in agriculture to control weeds in farmland and protect crops from weed competition, thereby increasing crop yield and quality. In addition, DEA can also replace tetraethyl aluminum as a gasoline antiknock agent and is also used in rubber additives and petrochemical fields.

[0004] At present, most industries use the synthesis technology of ortho-alkylation of o-toluidine and aniline with ethylene under the action of catalyst to produce MEA and DEA. During the alkylation reaction, the pressure and temperature control requirements are high. The alkylation pressure of aniline and ethylene is about 4.5MPa, and the reaction pressure of o-toluidine and ethylene is about 3.0-3.5MPa. The initiation temperature of alkylation is about 320℃.

[0005] The selectivity of the alkylation reaction is affected by pressure and temperature. The use of reaction conditions with low temperature and high pressure can better obtain higher selectivity (polyethyl compounds in the product, that is, fewer heavy components), but low temperature will significantly reduce the reaction rate. In addition, the synthesis process is an exothermic reaction, which also increases the difficulty of precise temperature control. The existing reactor adopts an overall heating method. During the alkylation reaction, the reactor reacts in the liquid phase and the gas phase. The two phases have different phase states, and the reaction degrees in the two phases are also different. There are differences in heat absorption and release. It is difficult to achieve precise temperature control. For this reason, the present invention proposes an alkylation reaction device and process in the synthesis of MEA and DEA. Summary of the invention

[0006] The object of the present invention is to provide an alkylation reaction device and process in the synthesis of MEA and DEA to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: an alkylation reaction device in the synthesis of MEA and DEA, comprising a main reactor and an upper cover and a lower cover connected to the main reactor, wherein a motor stirrer driven by a motor is installed on the upper cover, and a feed nozzle, an upper thermometer and a pressure element are also provided on the upper cover;

[0008] The main reactor is provided with an external heating / cooling coil outside, and a lower thermometer installed through the main reactor is provided below the external heating / cooling coil, and the lower thermometer is arranged horizontally; a feed distribution nozzle is also fixedly installed on one side wall of the main reactor, and a discharge port is provided at the lower end of the lower cover;

[0009] The end of the feed nozzle away from the main reactor is connected to a feed pump through a connecting pipe, and the end of the feed pump away from the feed nozzle is connected to a preheating storage tank. A heating inner coil is installed inside the preheating storage tank, and a storage tank thermometer is also inserted and installed on the preheating storage tank.

[0010] As a preferred technical solution of the present invention, the external heating / cooling coil is attached to the outer wall of the main reactor, and the main reactor is arranged in a serpentine spiral.

[0011] As a preferred technical solution of the present invention, the inner heating coil is attached to the inner wall of the preheating storage tank, and the inner heating coil is arranged in a serpentine spiral.

[0012] As a preferred technical solution of the present invention, the feed nozzle is an atomizing nozzle, and the feed nozzle includes a first feed atomizing nozzle and a second feed atomizing nozzle, and the second feed atomizing nozzle and the first feed atomizing nozzle are symmetrically arranged on the upper cover.

[0013] As a preferred technical solution of the present invention, the feed nozzle is provided with a plurality of atomization holes, the atomization hole diameter is 0.5-1.5 mm, and the feed pressure of the feed nozzle is 3.0-5.5 MPa.

[0014] As a preferred technical solution of the present invention, a feed port is provided on the top of the preheating storage tank.

[0015] As a preferred technical solution of the present invention, the feed pump is a high temperature and high pressure pump with a pressure of 0-10 MPa.

[0016] As a preferred technical solution of the present invention, a flow meter is installed on the connecting pipe, and the flow meter is a liquid flow meter.

[0017] As a preferred technical solution of the present invention, the material of the external heating / cooling coil is stainless steel, and the heat medium / cooling medium inside the external heating / cooling coil is heat transfer oil.

[0018] The alkylation reaction process in the synthesis of MEA and DEA includes the following steps:

[0019] A. The liquid phases of aniline, o-toluidine and catalyst involved in the alkylation reaction are pumped into the preheating storage tank through the feeding port;

[0020] B. Control the heat medium of the heating coil in the preheating storage tank to 150-250℃ to heat the liquid phase; at the same time, stabilize the temperature of the heating / cooling coil in the main reactor at 320℃;

[0021] C. When the mixed liquid phase temperature in the preheating storage tank is above 150°C, the mixed liquid enters the main reactor through the feed pump and the two feed atomizing nozzles in the upper cover of the main reactor. The feed pressure is greater than the pressure in the reactor and is controlled at 3.0-5.5MPa;

[0022] D, connected, and at the same time, ethylene gas at 280°C is fed into the feed distribution nozzle in the middle of the main reactor, and the gas is evenly distributed after passing through the distribution nozzle and contacts with the atomized liquid for reaction;

[0023] E. During the reaction, the temperature of the heat transfer oil in the outer coil of the main reactor was adjusted to fine-tune the temperature to 320°C;

[0024] F. After the reaction is completed, the temperature of the heat transfer oil in the outer coil of the main reactor is adjusted to slowly cool down. At the same time, the agitator in the main reactor is turned on to stabilize the temperature of the liquid in the reactor to below 120° C. and the material is discharged from the lower discharge port of the main reactor.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The alkylation reaction device and process in the synthesis of MEA and DEA of the present invention have a simple structure and are different from the existing reaction devices: they are mainly divided into two temperature control units, firstly, the temperature control of the main reaction zone, the reactor feed is divided into high-temperature gas and preheated high-temperature atomized liquid, mixed and reacted in the reactor, and the temperature is adjusted by an external heating / cooling coil, so that accurate and stable temperature control can be achieved; secondly, the liquid feed outside the reactor is preheated to above 120° C. in a preheating storage tank and pumped into the reactor through a high-pressure pump; the liquid phase is temperature controlled separately, so that the temperature fluctuation amplitude is small when the material enters the reactor to participate in the reaction, and it is easier to accurately control the temperature, which is conducive to the stable reaction, and finally obtains a high-purity target product; therefore, the two sets of independent heating / cooling temperature control systems inside and outside can realize accurate temperature control of the alkylation reaction, and have strong practicality and good application prospects.

[0027] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0029] In the figure: 1. motor stirrer, 2. first feed atomizing nozzle, 3. upper thermometer, 4. upper cover, 5. external heating / cooling coil, 6. feed distribution nozzle, 7. lower thermometer, 8. lower cover, 9. discharge port, 10. second feed atomizing nozzle, 11. pressure element, 12. main reactor, 13. flow meter, 14. feed pump, 15. preheating storage tank, 16. heating inner coil, 17. feed port, 18. storage tank thermometer. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] See also Figure 1 In this embodiment, an alkylation reaction device in the synthesis of MEA and DEA is provided, comprising a main reactor 12 and an upper cover 4 and a lower cover 8 connected to the main reactor 12, a motor stirrer 1 driven by a motor is installed on the upper cover 4, a feed nozzle, an upper thermometer 3 and a pressure element 11 are also provided on the upper cover 4; a stirring blade is provided at the bottom of the motor stirrer 1, the stirring blade covers the middle part and extends to the lower cover area,

[0034] The outside of the main reactor 12 is provided with an external heating / cooling coil 5, and a lower thermometer 7 is provided below the external heating / cooling coil 5 and is installed through the main reactor 12, and the lower thermometer 7 is arranged horizontally; a feed distribution nozzle 6 is also fixedly installed on one side wall of the main reactor 12, and a discharge port 9 is provided at the lower end of the lower cover 8; the feed distribution nozzle 6 is porous and evenly distributed, with a pore size of 0.5-1.5mm and a feed pressure of 3.0-5.5MPa. The porous feed under high pressure is evenly distributed and fully in contact with the atomized liquid phase, which can accelerate the reaction, and the feed is high-temperature ethylene gas; the upper thermometer 3 and the lower thermometer 7 are both insertion thermometers;

[0035] The end of the feed nozzle away from the main reactor 12 is connected to the feed pump 14 through a connecting pipe, and the end of the feed pump 14 away from the feed nozzle is connected to the preheating storage tank 15, and the preheating storage tank 15 is installed with a heating inner coil 16, and a storage tank thermometer 18 is also inserted and installed on the preheating storage tank 15. The preheating storage tank 15 is cylindrical or square, and the material is temperature-resistant above 200°C; the heating coil is made of stainless steel, and the internal heat medium is heat transfer oil or high-pressure steam.

[0036] In this embodiment, the external heating / cooling coil 5 is attached to the outer wall of the main reactor 12, and the main reactor 12 is arranged in a serpentine spiral.

[0037] In this embodiment, the heating inner coil 16 is attached to the inner wall of the preheating storage tank 15, and the heating inner coil 16 is arranged in a serpentine spiral.

[0038] In this embodiment, the feed nozzle is an atomizing nozzle, and the feed nozzle includes a first feed atomizing nozzle 2 and a second feed atomizing nozzle 10 . The second feed atomizing nozzle 10 and the first feed atomizing nozzle 2 are symmetrically arranged on the upper cover 4 .

[0039] In this embodiment, the feed nozzle is provided with multiple atomization holes, the atomization hole diameter is 0.5-1.5mm, and the feed pressure of the feed nozzle is 3.0-5.5MPa; the porous feed under high pressure is evenly distributed and fully in contact with the high-temperature ethylene gas, which can accelerate the reaction; the upper cover is provided with a thermometer and a pressure gauge access port, and the temperature and pressure elements are connected.

[0040] In this embodiment, a feed port 17 is provided at the top of the preheating storage tank 15 .

[0041] In this embodiment, the feed pump 14 is a high temperature and high pressure pump with a pressure of 0-10 MPa.

[0042] In this embodiment, a flow meter 13 is installed on the connecting pipe, and the flow meter 13 is a liquid flow meter.

[0043] In this embodiment, the material of the external heating / cooling coil 5 is stainless steel, and the heat medium / cooling medium inside the external heating / cooling coil 5 is heat transfer oil.

[0044] In this embodiment, an alkylation reaction process in the synthesis of MEA and DEA is also provided, comprising the following steps:

[0045] A. The liquid phases of aniline, o-toluidine and catalyst involved in the alkylation reaction are pumped into the preheating storage tank through the feeding port;

[0046] B. Control the heat medium of the heating coil in the preheating storage tank to 150-250℃ to heat the liquid phase; at the same time, stabilize the temperature of the heating / cooling coil in the main reactor at 320℃;

[0047] C. When the mixed liquid phase temperature in the preheating storage tank is above 150°C, it enters the main reactor through the feed pump and the two feed atomizing nozzles in the upper cover of the main reactor. The feed pressure is greater than the pressure in the reactor and is controlled at 3.0-5.5MPa;

[0048] D. At the same time, ethylene gas at 280°C is fed into the main reactor through the feed distribution nozzle in the middle of the main reactor. After passing through the distribution nozzle, the gas is evenly distributed and contacts the atomized liquid for reaction;

[0049] E. During the reaction, the temperature of the heat transfer oil in the outer coil of the main reactor was adjusted to fine-tune the temperature to 320°C;

[0050] F. After the reaction is completed, adjust the temperature of the heat transfer oil in the coil outside the main reactor to slowly cool it down. At the same time, turn on the agitator in the main reactor to stabilize the liquid temperature in the reactor to below 120°C, and unload from the lower discharge port of the main reactor.

[0051] During the entire reaction temperature control stage, two independent split temperature control systems are used to control the temperature of the liquid phase and the reaction gas-liquid mixed phase respectively in different areas of the reaction system, achieving precise temperature control and stabilizing the reaction under high pressure and relatively low temperature.

[0052] The alkylation reaction device of the present invention has a simple structure. Compared with the existing reaction device, the temperature control unit and the liquid phase preheating unit required for the reaction are separately controlled and temperature-regulated. The separate control is conducive to precise temperature and pressure control. At the same time, the operation is safe and convenient, the control effect is good, the final target product yield and purity are high, and the device has strong practicality and good application prospects.

[0053] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Alkylation reaction device in MEA and DEA synthesis, characterized in that: The invention comprises a main reactor (12) and an upper cover (4) and a lower cover (8) connected to the main reactor (12); a motor stirrer (1) driven by a motor is installed on the upper cover (4); a feed nozzle, an upper thermometer (3) and a pressure element (11) are also provided on the upper cover (4); The main reactor (12) is provided with an external heating / cooling coil (5) outside, and a lower thermometer (7) is provided below the external heating / cooling coil (5) and is installed through the main reactor (12), and the lower thermometer (7) is arranged horizontally; a feed distribution nozzle (6) is also fixedly installed on one side wall of the main reactor (12), and a discharge port (9) is provided at the lower end of the lower cover (8); The end of the feed nozzle away from the main reaction kettle (12) is connected to a feed pump (14) through a connecting pipe, and the end of the feed pump (14) away from the feed nozzle is connected to a preheating storage tank (15), and a heating inner coil (16) is installed inside the preheating storage tank (15). A storage tank thermometer (18) is also inserted and installed on the preheating storage tank (15).

2. The alkylation reaction device in the synthesis of MEA and DEA according to claim 1, characterized in that: The external heating / cooling coil (5) is attached to the outer wall of the main reactor (12), and the main reactor (12) is arranged in a serpentine spiral.

3. The alkylation reaction device in the synthesis of MEA and DEA according to claim 1, characterized in that: The heating inner coil (16) is attached to the inner wall of the preheating material storage tank (15), and the heating inner coil (16) is arranged in a serpentine spiral.

4. The alkylation reaction device in the synthesis of MEA and DEA according to claim 1, characterized in that: The feed nozzle is an atomizing nozzle, and the feed nozzle comprises a first feed atomizing nozzle (2) and a second feed atomizing nozzle (10), wherein the second feed atomizing nozzle (10) and the first feed atomizing nozzle (2) are symmetrically arranged on the upper cover (4).

5. The alkylation reaction device in the synthesis of MEA and DEA according to claim 4, characterized in that: The feed nozzle is provided with a plurality of atomization holes, the diameter of the atomization holes is 0.5-1.5 mm, and the feed pressure of the feed nozzle is 3.0-5.5 MPa.

6. The alkylation reaction device in the synthesis of MEA and DEA according to claim 1, characterized in that: The top of the preheating storage tank (15) is provided with a feed inlet (17).

7. The alkylation reaction device in the synthesis of MEA and DEA according to claim 1, characterized in that: The feed pump (14) is a high temperature and high pressure resistant pump with a pressure of 0-10 MPa.

8. The alkylation reaction device in the synthesis of MEA and DEA according to claim 1, characterized in that: A flow meter (13) is installed on the connecting pipe, and the flow meter (13) is a liquid flow meter.

9. The alkylation reaction device in the synthesis of MEA and DEA according to claim 1, characterized in that: The material of the external heating / cooling coil (5) is stainless steel, and the heat medium / cooling medium inside the external heating / cooling coil (5) is heat transfer oil.

10. Alkylation reaction process in the synthesis of MEA and DEA, characterized in that: The steps include: A. The liquid phases of aniline, o-toluidine and catalyst involved in the alkylation reaction are pumped into the preheating storage tank through the feeding port; B. Control the heat medium of the heating coil in the preheating storage tank to 150-250℃ to heat the liquid phase; at the same time, stabilize the temperature of the heating / cooling coil in the main reactor at 320℃; C. When the mixed liquid phase temperature in the preheating storage tank is above 150°C, the mixed liquid enters the main reactor through the feed pump and the two feed atomizing nozzles in the upper cover of the main reactor. The feed pressure is greater than the pressure in the reactor and is controlled at 3.0-5.5MPa; D, connected, and at the same time, ethylene gas at 280°C is fed into the feed distribution nozzle in the middle of the main reactor, and the gas is evenly distributed after passing through the distribution nozzle and contacts with the atomized liquid for reaction; E. During the reaction, the temperature of the heat transfer oil in the outer coil of the main reactor was adjusted to fine-tune the temperature to 320°C; F. After the reaction is completed, the temperature of the heat transfer oil in the outer coil of the main reactor is adjusted to slowly cool down. At the same time, the agitator in the main reactor is turned on to stabilize the temperature of the liquid in the reactor to below 120° C. and the material is discharged from the lower discharge port of the main reactor.

Images