Diphenylmethane series amine reaction device

Abstract

The utility model discloses a diphenylmethane series amine reaction device, and belongs to the technical field of integrated condensation reactors, the diphenylmethane series amine reaction device comprises a salifying-condensation reactor, a plug flow reactor is arranged on one side of the salifying-condensation reactor, the salifying-condensation reactor comprises a reaction kettle, a double-layer hollow stirring shaft is arranged in the reaction kettle, and the double-layer hollow stirring shaft is connected with the plug flow reactor. A static mixer is arranged on one side of the reaction kettle; the multi-nozzle static mixer with the built-in condensation assembly can strengthen the mixing effect, the static mixer is directly connected with the reaction kettle, salt forming reaction liquid can be effectively prevented from staying in a pipeline and reducing the color of a system, and the hollow stirring shaft is beneficial to rapid mixing and timely removal of reaction heat; according to the device, aniline and hydrochloric acid as well as aniline hydrochloride and formaldehyde are rapidly and uniformly mixed, reaction heat is removed, local overheating and hot spots are avoided, generation of by-products can be reduced, colors of products and downstream products are effectively improved, the quality of the downstream products is improved, and the device is suitable for large-scale industrial production and high in synthesis efficiency.

Description

Technical Field

[0001] The present application belongs to the technical field of integrated condensation reactors, and in particular relates to a diphenylmethane series amine reaction device. Background Art

[0002] Diphenylmethane series amines (DAM) include a mixture of diphenylmethane series diamines and polyamines, and its structure is

[0003]

[0004] Wherein n is an integer ≥0; when n is 0, it is diaminodiphenylmethane (diamine, MDA); when n ≥ 1, it is polymethylene polyphenyl polyamine (polyamine), and DAM is a mixture of the above diamines and polyamines; DAM is widely used in the production of diphenylmethane series isocyanates (MDI, diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate) and is one of the important raw materials in the polyurethane industry; in the traditional DAM preparation process, aniline is mixed with hydrochloric acid to form aniline hydrochloride, which is then mixed with formaldehyde for a condensation reaction, followed by transposition rearrangement, neutralization and washing, and finally the oil phase product is refined to obtain the DAM product.

[0005] It is well known in the art that the salt-forming reaction between aniline and hydrochloric acid is an exothermic reaction. If the mixing is uneven, local hot spots will form, causing side reactions such as aniline oxidation, deamination, and polymerization, resulting in a darker color of the aniline hydrochloride product. In addition, if the salt-forming reaction liquid resides in the pipeline for a long time, the color of the salt-forming reaction liquid will also darken, resulting in aniline loss. At the same time, the color of downstream products produced by the photochemical reaction of MDA, such as MDI products, will darken, affecting the quality of downstream products.

[0006] At the same time, the reaction between formaldehyde and aniline hydrochloride is a rapid reaction, which occurs the moment the raw materials come into contact and releases a large amount of heat. Therefore, in the industrial production process, it is very easy for formaldehyde to be unevenly dispersed in the pre-reaction liquid, resulting in local excessive concentration of formaldehyde and excessive temperature, thereby aggravating the condensation side reaction, leading to the production of by-products and network polymers, seriously affecting the quality of polyamines. At the same time, the viscosity of the reactant system is high, and in severe cases, pipeline blockage may occur.

[0007] The key factors in controlling the reaction are to quickly and evenly mix aniline with hydrochloric acid and aniline hydrochloride with formaldehyde and to remove the heat of reaction to ensure that no local excess or hot spots occur.

[0008] US3260751 describes the use of an L-shaped mixing reactor in which aniline hydrochloride, produced by the reaction of aniline and hydrochloric acid, reacts with formaldehyde. This ensures turbulent flow to prevent the formation of high molecular weight polymers and the resulting equipment clogging. Using this reactor for the condensation reaction merely improves the flow of the reactants to address equipment clogging, but it does not effectively reduce the impurity content in the DAM product.

[0009] CN101279923A discloses a method for preparing polymethylene polyphenyl polyamines (DAMs). This method uses a high-gravity rotating bed as a mixing reactor for formaldehyde and aniline hydrochloride. However, during industrial application, this method suffers from the phenomenon that the reaction product of formaldehyde and aniline hydrochloride sprayed onto the rotating bed adheres to the rotor of the rotating bed, leading to blockage of the bed pores and a sharp increase in the stirring current, resulting in poor operational stability. Furthermore, CN102527312A and CN103084134A respectively describe two mixing enhancement devices and methods for producing DAM. While these devices facilitate rapid mixing of materials, they lack sufficient microscopic mixing during actual large-scale industrial production applications, resulting in a high impurity content of N-methyl MDA and incompletely resolving the clogging problem caused by the polymer. Utility Model Content

[0010] The present application provides a diphenylmethane series amine reaction device, which solves the problem that the salt-forming reaction liquid stays in the pipeline, causing the salt-forming reaction liquid to darken in color, increase side reactions, and low quality of downstream products.

[0011] An embodiment of the present application provides a diphenylmethane series amine reaction device, including a salt formation-condensation reactor, a plug flow reactor is provided on one side of the salt formation-condensation reactor, the salt formation-condensation reactor includes a reactor, a double-layer hollow stirring shaft is provided in the reactor, and a static mixer is provided on the other side of the reactor.

[0012] In one embodiment,

[0013] The double-layer hollow stirring shaft includes a shaft body, the shaft body includes an inner channel, and an outer channel is sleeved on the outer side of the inner channel; dispersion blades and cooling blades are equidistantly provided on the shaft body; the number of the dispersion blades and cooling blades is at least 2, and preferably, the number of the dispersion blades and cooling blades is 4.

[0014] In one embodiment,

[0015] The inner layer channel is communicated with the cooling blade, and the outer layer channel is communicated with the dispersing blade.

[0016] In one embodiment,

[0017] The shaft body passes through the top and bottom of the reactor.

[0018] In one embodiment,

[0019] The dispersing blades are provided with evenly distributed dispersing holes.

[0020] In one embodiment,

[0021] The static mixer comprises a mixing chamber, on which multiple layers of nozzles are equidistantly provided, with each layer having at least two nozzles. Preferably, three layers of nozzles are provided, with each layer having six nozzles.

[0022] In one embodiment,

[0023] A condensation component is provided in the mixing chamber.

[0024] In one embodiment,

[0025] A condensation reaction liquid outlet is provided on one side of the reactor, a transposition reaction liquid outlet is provided on one side of the plug flow reactor, and a motor is provided on the double-layer hollow stirring shaft.

[0026] In one embodiment,

[0027] The inner wall of the plug flow reactor is provided with a heating jacket, and the number of the heating jackets is at least 1, and preferably, the number of the heating jackets is 3; a heat medium inlet is provided on one side of the plug flow reactor, and a heat medium outlet is provided on the other side, and the number of the heat medium inlet and the heat medium outlet is at least 1, and preferably, the number of the heat medium inlet and the heat medium outlet is 3; a partition is provided in the plug flow reactor, and the number of the partition is at least 1, and preferably, the number of the partition is 8.

[0028] In one embodiment,

[0029] A vacuum insulation partition is provided between the plug flow reactor and the salt formation-condensation reactor.

[0030] The present application provides a diphenylmethane series amine reaction device, which adopts a multi-nozzle static mixer with a built-in condensation component to perform convection and cross-current mixing, enhance the mixing effect, reduce the system temperature, and mix uniformly; the static mixer is directly connected to the reactor, which can effectively prevent the salt-forming reaction liquid from staying in the pipeline, reduce the color of the system, reduce the formation of by-products, and reduce the chromaticity of the diphenylmethane series amine downstream products; the double-layer hollow stirring shaft adopts the dispersion holes on the dispersion blades to feed the material, which is conducive to rapid mixing. At the same time, the double-layer stirring shaft is provided, and the reaction liquid is cooled while reacting, and the reaction heat is quickly removed, the formation of hot spots is avoided, and the reaction by-products are reduced; the present device allows aniline and hydrochloric acid, as well as aniline hydrochloride and formaldehyde, to be quickly and uniformly mixed and the reaction heat is removed, ensuring that local overheating and hot spots do not occur, which can reduce the generation of by-products, effectively improve the color of the product and downstream products, and improve the quality of downstream products. It is suitable for large-scale industrial production and has high synthesis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 This is the general assembly diagram of the diphenylmethane series amine reaction device;

[0033] Figure 2 Figure 2 is a structural diagram of a salt-forming-condensation reactor;

[0034] Figure 3 Figure 1 shows different numbers of nozzles.

[0035] Figure 4 This is a structural diagram of the dispersion blades and cooling blades of Example 4.

[0036] Explanation of symbols in the figure:

[0037] A. Aniline; B. Hydrochloric acid; C. Formaldehyde; D. Refrigerant medium outlet; E. Refrigerant medium inlet; 1. Salt formation-condensation reactor; 2. Plug flow reactor; 3. Reactor; 4. Double-layer hollow stirring shaft; 41. Shaft body; 5. Static mixer; 6. Inner channel; 7. Outer channel; 8. Dispersion blade; 9. Cooling blade; 10. Dispersion hole; 11. Mixing chamber; 12. Nozzle; 13. Condensation assembly; 141. Condensation reaction liquid outlet; 142. Transfer reaction liquid outlet; 15. Motor; 16. Heating jacket; 17. Heat medium inlet; 18. Heat medium outlet; 19. Vacuum insulation partition; 20. Partition. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clear and understandable, this application is further described in detail. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0039] Example 1

[0040] A diphenylmethane series amine reaction device, such as Figure 1 As shown, it includes a salt-forming-condensation reactor 1, and a plug flow reactor 2 is provided on one side of the salt-forming-condensation reactor 1. Figure 2 As shown, the salt formation-condensation reactor 1 includes a reactor 3 , a double-layer hollow stirring shaft 4 is provided in the reactor 3 , and a static mixer 5 is provided on one side of the reactor 3 .

[0041] Specifically, the salt-forming-condensation reactor 1 is used for the salt-forming reaction of aniline A and hydrochloric acid B, and the plug flow reactor 2 is used for the gradient heating and transposition reaction of the condensation reaction liquid of aniline hydrochloride and formaldehyde C; the reactor 3 provides a condensation reaction site, and the double-layer hollow stirring shaft 4 is used for stirring, uniformly dispersing formaldehyde C, and cooling; the static mixer 5 is used to transport the raw materials aniline A and hydrochloric acid B, enhance mixing and cooling, and carry out the salt-forming reaction.

[0042] The double-layer hollow stirring shaft 4 includes a shaft body 41, which includes an inner channel 6, and an outer channel 7 is sleeved on the outside of the inner channel 6; dispersion blades 8 and cooling blades 9 are equidistantly provided on the shaft body 41; the number of dispersion blades 8 and cooling blades 9 is at least 2, and in this embodiment, the number of dispersion blades 8 and cooling blades 9 is 6; the inner channel 6 is connected to the cooling blades 9, and the outer channel 7 is connected to the dispersion blades 8; the shaft body 41 runs through the top and bottom of the reactor 3; the dispersion blades 8 are provided with evenly distributed dispersion holes 10; the double-layer hollow stirring shaft 4 is provided with a motor 15.

[0043] Specifically, the double-layer hollow stirring shaft 4 is designed as a double-layer hollow structure. Formaldehyde C is fed from the outer channel 7 and dispersed into the reactor 3 through the dispersion holes 10 on the dispersion blades 8. It is quickly mixed with the salt-forming reaction liquid under the mixing of the double-layer hollow stirring shaft 4 to reduce the formation of reaction hot spots; the inner channel 6 is for refrigerant feed, and the refrigerant medium can remove the reaction heat in time to avoid the formation of by-products; the motor 15 is used to drive the double-layer hollow stirring shaft 4 to rotate.

[0044] In this embodiment, the dispersion blades 8 are symmetrically arranged in pairs to form a layer, and the cooling blades 9 are symmetrically arranged in pairs to form a layer, for a total of six layers. The dispersion blades 8 and the cooling blades 9 are designed as interlayers, i.e., one layer is the dispersion blades 8 and the other layer is the cooling blades 9.

[0045] The static mixer 5 includes a mixing chamber 11, on which multiple layers of nozzles 12 are equidistantly provided, with at least two nozzles 12 on each layer; a condensation assembly 13 is provided in the mixing chamber 11; a condensation reaction liquid outlet 141 is provided on one side of the reactor 3, and a transposition reaction liquid outlet 142 is provided on one side of the plug flow reactor 2.

[0046] Specifically, the static mixer 5 is arranged between the bottom and the middle of the side of the reactor 3. In this embodiment, the number of nozzles 12 is 6, and two nozzles 12 form a layer, which are respectively arranged on the upper and lower sides of the mixing chamber 11, for a total of three layers; the two nozzles 12 in each layer are fed with different substances to form convection mixing, and the nozzles 12 on the same side of the two adjacent layers are fed with different substances to form cross-flow mixing; Figure 3 As shown, multiple nozzles 12 can be set on each layer, such as 2, 4 or 6, and 2 in this embodiment. The nozzles 12 can enhance the mixing effect; the condensation component 13 can be set to different shapes according to the heat exchange requirements, such as coil type, wing type, spiral fan type, etc. The condensation component 13 can not only perform heat exchange, but also increase the turbulence effect of the logistics, thereby further enhancing the mixing effect; the condensation reaction liquid outlet 141 on one side of the reactor 3 can discharge the condensation reaction liquid into the plug flow reactor 2, and the transposition reaction liquid outlet 142 can discharge the transposition reaction liquid.

[0047] The inner wall of the plug flow reactor 2 is provided with a heating jacket 16, and the number of the heating jackets 16 is at least 1, and in this embodiment, there are 3; a heat medium inlet 17 is provided on one side of the plug flow reactor 2, and a heat medium outlet 18 is provided on the other side. The number of the heat medium inlet 17 and the heat medium outlet 18 is at least 1, and in this embodiment, the number of the heat medium inlet 17 and the heat medium outlet 18 are both 3; a vacuum insulation partition 19 is provided between the plug flow reactor 2 and the salt formation-condensation reactor 1, and a partition 20 is provided in the plug flow reactor 2. The number of the partition 20 is at least 1, and in this embodiment, the number of the partitions 20 is 8.

[0048] Specifically, the plug flow reactor 2 is a baffle-type plug flow reactor, and the plug flow reactor 2 can be designed with 2-20 different temperature ranges according to different temperature gradients; the heating jacket 16 is arranged on the inner wall of the plug flow reactor 2 according to the shape of the plug flow reactor 2, and the number is consistent with the heat medium inlet 17 and the heat medium outlet 18, which is used for gradient heating, and the vacuum insulation partition 19 ensures that no heat exchange occurs between the materials on both sides of the vacuum insulation partition 19; the partitions 20 are staggered up and down, forming an S-shaped arrangement in the plug flow reactor 2, and a plug flow has been formed.

[0049] Example 2

[0050] like Figure 3 As shown, the difference from Example 1 is that the four nozzles 12 in the static mixer 5 of this embodiment form a layer, and the rest of the configuration is the same.

[0051] Example 3

[0052] The difference from Example 1 is that the six nozzles 12 in the static mixer 5 of this embodiment form a layer, and the rest of the configuration is the same.

[0053] Example 4

[0054] like Figure 4 As shown, different from Example 1, the dispersing blades 8 and cooling blades 9 of this embodiment are distributed in an equidistant radial pattern on the same double-layer hollow stirring shaft 4, with each layer having four dispersing blades 8 and four cooling blades 9, and the rest of the settings are the same.

[0055] The present application provides a diphenylmethane series amine reaction device, including a salt-forming-condensation reactor, a plug flow reactor is provided on one side of the salt-forming-condensation reactor, the salt-forming-condensation reactor includes a reactor, a double-layer hollow stirring shaft is provided in the reactor, and a static mixer is provided on one side of the reactor; a multi-nozzle static mixer with a built-in condensation component is used to perform convection and cross-flow mixing, thereby enhancing the mixing effect, reducing the system temperature, and mixing uniformly; the static mixer is directly connected to the reactor, which can effectively avoid the salt-forming reaction liquid from staying in the pipeline, reducing the color of the system, reducing the formation of by-products, and reducing diphenylmethane. The chromaticity of downstream products of the methylmethane series amines is improved; the double-layer hollow stirring shaft adopts the dispersion holes on the dispersion blades to feed the materials, which is conducive to rapid mixing. At the same time, the double-layer stirring shaft is set, and the reaction liquid is cooled while reacting, and the reaction heat is quickly removed, avoiding the formation of hot spots and reducing reaction by-products; this device can quickly and evenly mix aniline and hydrochloric acid, as well as aniline hydrochloride and formaldehyde, and remove the reaction heat, ensuring that no local overheating or hot spots occur, which can reduce the generation of by-products, effectively improve the color of the product and downstream products, and improve the quality of downstream products. It is suitable for large-scale industrial production and has high synthesis efficiency.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0057] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A diphenylmethane series amine reaction device, comprising a salt formation-condensation reactor, wherein a plug flow reactor is provided on one side of the salt formation-condensation reactor, characterized in that: The salt-forming-condensation reactor comprises a reactor, a double-layer hollow stirring shaft is arranged in the reactor, and a static mixer is arranged on one side of the reactor.

2. A diphenylmethane series amine reaction device according to claim 1, characterized in that, The double-layer hollow stirring shaft includes a shaft body, which includes an inner channel, and an outer channel is sleeved on the outer side of the inner channel; dispersion blades and cooling blades are equidistantly arranged on the shaft body; the number of the dispersion blades and cooling blades is at least 2.

3. A diphenylmethane series amine reaction device according to claim 2, characterized in that, The inner layer channel is communicated with the cooling blade, and the outer layer channel is communicated with the dispersing blade.

4. A diphenylmethane series amine reaction device according to claim 2, characterized in that, The shaft body passes through the top and bottom of the reactor.

5. A diphenylmethane series amine reaction device according to claim 2, characterized in that, The dispersing blades are provided with evenly distributed dispersing holes.

6. A diphenylmethane series amine reaction device according to claim 1, characterized in that, The static mixer comprises a mixing chamber, on which multiple layers of nozzles are evenly spaced, and each layer has at least two nozzles.

7. A diphenylmethane series amine reaction device according to claim 6, characterized in that, A condensation component is provided in the mixing chamber.

8. A diphenylmethane series amine reaction device according to claim 1, characterized in that, A condensation reaction liquid outlet is provided on one side of the reactor, a transposition reaction liquid outlet is provided on one side of the plug flow reactor, and a motor is provided on the double-layer hollow stirring shaft.

9. A diphenylmethane series amine reaction device according to claim 1, characterized in that, The inner wall of the plug flow reactor is provided with a heating jacket, and the number of the heating jacket is at least one; a heat medium inlet is provided on one side of the plug flow reactor, and a heat medium outlet is provided on the other side, and the number of the heat medium inlet and the heat medium outlet is at least one; a partition is provided in the plug flow reactor, and the number of the partition is at least one.

10. A diphenylmethane series amine reaction device according to claim 1, characterized in that, A vacuum insulation partition is provided between the plug flow reactor and the salt formation-condensation reactor.

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