A high shear mixing reactor and a method for preparing diphenylmethane series amines

Abstract

The present invention provides a high shear mixing reactor and a method for preparing diphenylmethane series amines, wherein the high shear mixing reactor comprises: a shell, a rotating shaft, a stator-rotor device of at least two stages, a first feed channel, a second feed channel and a discharge channel; through the design of at least two stages of tooth array interlocking stator-rotor devices and feed channels, the materials can quickly and fully complete the dispersion and mixing of molecular scale, solve the problem of local excess of materials, and inhibit the occurrence of side reactions. The high shear mixing reactor is used for the preparation of diphenylmethane series amines DAM, and the rapid and easy-to-block liquid-liquid reaction system of aniline salt and formaldehyde is improved, the pipeline and equipment blockage problem is solved, and the preparation method of DAM has the characteristics of no energy waste, simple operation, stable operation, and high reaction heat utilization rate, and the content of N-methyl MDA impurities and polymers is reduced to a level significantly ahead of the current industry, and DAM has excellent and stable quality.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical preparation, and in particular relates to a high shear mixing reactor and a method for preparing diphenylmethane series amines. Background Art

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

[0003] The method of producing DAM by reacting aniline with formaldehyde in the presence of an acidic catalyst is known in the industry. The reaction is carried out in a continuous, semi-continuous or discontinuous system. In the process of producing DAM in large-scale industrial equipment, uneven dispersion of formaldehyde is very likely to occur, and there will be more local areas of excess formaldehyde in the system, which will lead to local overheating and excessive formaldehyde ratio, and produce by-products N-methyl impurities and polymers. The increase in the content of N-methyl impurities will seriously affect the quality of DAM and subsequent MDI; polymers will cause blockage of equipment and pipelines, affecting the stable operation of the overall production of MDI. In severe cases, the operation may need to be stopped for cleaning after a period of time.

[0004] In response to this problem, domestic and foreign researchers have conducted various research works. For example, EP1270544A1 discloses that aniline, formaldehyde and acid catalyst are added in stages multiple times in a semi-continuous manner to control the N-methyl MDA content in DAM, which can reduce the color number of crude MDI; however, this method is a semi-continuous production method, and it is difficult to achieve large-scale industrial production of DAM and MDI. USP3260751A discloses a process for preparing polyamines by continuous condensation, which adopts an "L"-shaped mixing device. Aniline hydrochloride prepared by the reaction of aniline and hydrochloric acid reacts with formaldehyde in a reactor to make the fluid in a turbulent state, avoiding the generation of high molecular weight polymers and equipment blockage; however, this method can only adjust the flow state of the material, and cannot well achieve rapid and sufficient mixing of formaldehyde and aniline, especially in large-scale industrial production, which will lead to more serious problems. CN101279923A discloses a method for preparing polymethylene polyphenyl polyamine DAM, which uses a supergravity rotating bed as a mixed reactor for formaldehyde and aniline hydrochloride, and feeds a mixed solution of aniline hydrochloride and circulating liquid and formaldehyde into the supergravity rotating bed reactor in proportion, mixes and undergoes condensation reaction under supergravity conditions, and the materials leaving the supergravity rotating bed reactor can enter a stirring kettle to continue pre-condensation reaction to obtain a condensation liquid, and then obtains refined DAM after heating, molecular rearrangement reaction, neutralization, water washing, and polyamine refining. However, in the process of industrial application, the method has the phenomenon that the reaction product of formaldehyde and aniline hydrochloride sprayed onto the rotating bed adheres to the rotor of the rotating bed, resulting in blockage of the bed channel and a sharp increase in stirring current, and poor operation stability. In addition, CN102527312A and CN103084134A respectively mention two mixing intensification devices and methods for producing DAM. Although they help to achieve rapid mixing of materials, in actual large-scale industrial production and application processes, the sufficient micro-mixing effect is poor, resulting in a high impurity content of N-methyl MDA, and the clogging problem caused by the polymer has not been completely solved.

[0005] At present, the production scale of single MDI equipment is getting larger and larger, and higher requirements are put forward for the quality and production capacity of DAM. The problems of N-methyl MDA impurities and highly polymerized blockages generated in the process of preparing DAM are becoming increasingly prominent. Therefore, it is urgent to find and develop a device that can meet the requirements of full dispersion of materials and a preparation process for high-quality DAM. Summary of the invention

[0006] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a high shear mixing reactor and a method for preparing diphenylmethane series amines. Through the special design of the high shear mixing reactor, especially the design of the stator-rotor device and the feed channel, the formaldehyde and other materials can be dispersed and mixed quickly and fully, and the side reaction is effectively suppressed. The method for preparing diphenylmethane series amines using the high shear mixing reactor has the characteristics of no energy waste, simple operation, stable operation, and low impurity content, so that the quality of the target product is excellent and stable.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In the first aspect, the present invention provides a high shear mixing reactor, which comprises: a shell, a rotating shaft, at least two-stage stator-rotor devices, a first feed channel, a second feed channel and a discharge channel; the stator and rotor in the stator-rotor device are engaged; the direction of the rotating shaft is the first direction, and the direction perpendicular to the first direction is the second direction; the at least two-stage stator-rotor devices include a first-stage stator-rotor device and a second-stage stator-rotor device arranged in sequence along the first direction; the first feed channel is arranged in the first direction, and the end thereof extending into the shell is a blind end; a discharge hole is provided on the side wall of the first feed channel near the blind end; the second feed channel is arranged in the second direction, and includes a first-stage feed sub-channel and a second-stage feed sub-channel; the first-stage feed sub-channel is arranged adjacent to the first-stage stator-rotor device, and the second-stage feed sub-channel is arranged adjacent to the second-stage stator-rotor device.

[0009] The high shear mixing reactor provided by the present invention comprises at least two levels (e.g., 2 levels, 3 levels, 4 levels, etc.) of tooth array interlocking stator and rotor devices, and the stator and rotor devices provide a very large shear rate, so that the materials can be efficiently, quickly, and fully mixed and dispersed at a microscopic scale in the high shear mixing reactor, thereby effectively suppressing the side reactions caused by the local excess of materials. At the same time, the high shear mixing reactor comprises a first feed channel and a second feed channel with mutually perpendicular arrangement directions, so that different materials enter the reactor from the two channels respectively; and the second feed channel comprises two levels of feed sub-channels, which are respectively arranged adjacent to the two-stage stator and rotor devices, and the materials entering from the first feed channel and the materials entering from the first feed sub-channel (second feed channel) are mixed in the high-speed shear zone where the first-stage stator and rotor device is located, and the materials are quickly dispersed at a huge energy dissipation rate to achieve molecular-level mixing, and then mixed with the materials entering from the second-stage feed sub-channel (second feed channel) in the high-speed shear zone where the second-stage stator and rotor device is located, and the materials are uniformly dispersed at a microscopic scale at a high-speed shear rate. In the high shear mixing reactor, the materials are dispersed and mixed quickly and fully at the molecular scale through at least two-stage gear-meshing stator-rotor devices and a special design of the feed channel, thereby effectively suppressing the occurrence of side reactions.

[0010] For example, the high shear mixing reactor is used for the preparation of diphenylmethane series amines. Aniline salt enters from the first feed channel, and formaldehyde enters through the second feed channel with a two-stage design. The high-speed shearing area of ​​the rotor and the stator is mixed, and the formaldehyde is heated to less than 10° at a huge energy dissipation rate. -3 s, achieving molecular-level mixing, reducing N-methyl MDA caused by local excess formaldehyde to the lowest level in the industry. At the same time, the multi-stage (at least 2-stage) stator-rotor device greatly suppresses the formation of polymers at a very high shear rate. The high-shear mixing reactor itself has strong anti-blocking and stable operation capabilities through shearing and biting even at a large flux and a reaction temperature of more than 100°C. The subsequent reaction and separation systems have no problems of equipment and pipeline blockage in various links after long-term operation.

[0011] It should be noted that, in the present invention, each stage of the stator-rotor device includes two stator-rotor devices arranged opposite to each other. Accordingly, in the second feed channel, the first-stage feed sub-channel and the second-stage feed sub-channel each include two sub-channels arranged opposite to each other; that is, the second feed channel includes four sub-channels.

[0012] Preferably, the high shear mixing reactor comprises a three-stage tooth array interlocking stator and rotor device.

[0013] In the present invention, the stator-rotor device includes a stator and a rotor; the stator includes a stator base and stator teeth arranged on the stator base, and the stator teeth are arranged in an array in a ring shape, that is, forming a "gear ring"; correspondingly, the rotor includes a rotor base and rotor teeth arranged on the rotor base, and the rotor teeth are arranged in an array in a ring shape, forming a "gear ring". The stator teeth and the rotor teeth are engaged with each other to form a stator-rotor device of tooth array engagement type. The stator base is fixed to the inner wall of the high shear mixing reactor (shell), and the rotor base is fixed to the rotating shaft.

[0014] Preferably, the number of gear rings in the stator is the same as the number of gear rings in the rotor, and the number of gear rings in the stator is 2-4, such as 2, 3 or 4.

[0015] Preferably, the spacing between the innermost gear ring and the outermost gear ring in the stator is 60-100 mm, for example, it can be 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm or 95 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0016] Preferably, the diameter of the outermost gear ring in the stator is 280-360 mm, for example, it can be 290 mm, 300 mm, 310 mm, 320 mm, 330 mm, 340 mm or 350 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0017] Preferably, the diameter of the innermost gear ring in the stator is 200-280 mm, for example, it can be 210 mm, 220 mm, 225 mm, 230 mm, 235 mm, 240 mm, 245 mm, 250 mm, 255 mm, 260 mm or 70 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0018] Preferably, the stator teeth in the stator and the rotor teeth in the rotor have the same tooth length; the tooth length is 80-120 mm, for example, it can be 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm or 115 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0019] Preferably, the tooth thickness of the stator teeth in the stator and the rotor teeth in the rotor are independently 1-6 mm, for example, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm or 5.5 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0020] Preferably, the spacing between any adjacent stator teeth and rotor teeth in the stator-rotor device is 5-15 mm, for example, it can be 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm or 14 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0021] Preferably, a multi-porous nozzle is provided at the discharge end of the second feed channel, and the multi-porous nozzle comprises an injection ring tube and at least two injection columns arranged on the injection ring tube; each of the injection columns is independently provided with 2-6 (for example, 3, 4, 5) injection holes.

[0022] Preferably, the number of the injection columns arranged on the injection ring tube is 4-8, for example, 5, 6 or 7.

[0023] Preferably, the diameter of the nozzle hole is 3-7 mm, for example, it can be 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm or 6.5 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0024] Preferably, the opening direction of the spray hole is toward the stator and rotor gear rings of the stator and rotor device and is perpendicular to the tangent direction of the gear rings.

[0025] As a preferred technical solution of the present invention, the number of the spray columns and spray holes of the multi-hole nozzle, and the diameter of the spray holes can be designed according to the feed amount and flow rate requirements.

[0026] In a second aspect, the present invention provides a use of the high shear mixing reactor as described in the first aspect in the preparation of amine compounds or isocyanate compounds.

[0027] In a third aspect, the present invention provides a method for preparing a diphenylmethane series amine, the preparation method comprising the following steps:

[0028] (1) Aniline reacts with an acidic compound to obtain an aniline salt;

[0029] (2) performing a pre-condensation reaction of the aniline salt obtained in step (1) with formaldehyde to obtain a reaction solution;

[0030] (3) reacting the reaction solution obtained in step (2) to obtain the diphenylmethane series amines;

[0031] Step (2) is carried out in a high shear mixing reactor as described in any one of claims 1 to 3, the aniline salt is fed from the first feed channel, the formaldehyde is fed from the second feed channel, and the obtained reaction solution is discharged from the discharge channel and enters step (3).

[0032] In the present invention, the diphenylmethane series amines are diphenylmethane series diamines and polyamines (DAM), the structure of which is Wherein, n is an integer ≥ 0; when n is 0, it is diaminodiphenylmethane (abbreviated as diamine, MDA); when n ≥ 1, it is polymethylene polyphenyl polyamine (polyamine), and DAM is a mixture of the above diamines and polyamines.

[0033] The preparation method provided by the present invention adopts the high shear mixing reactor, which is a method for continuously preparing DAM; wherein, the mixing and pre-condensation reaction of aniline salt and formaldehyde is carried out in the high shear mixing reactor. Specifically, aniline salt is fed from the first feeding channel, and formaldehyde is fed from the second feeding channel with a multi-stage (two-stage) design, and is added in a multi-hole injection manner through a multi-hole nozzle, and mixed in the high-speed shear area of ​​the rotor and the stator, and the formaldehyde is dissipated at a huge energy dissipation rate at a speed of less than 10 -3 s, and achieve molecular-level mixing, thereby effectively avoiding uneven formaldehyde dispersion and local formaldehyde excess, inhibiting side reactions, and reducing N-methyl MDA impurities caused by local formaldehyde excess to the lowest level in the industry; at the same time, the stator-rotor device with multi-stage (at least two-stage) tooth array engagement effectively inhibits the formation of polymers at a very high shear rate, and the high-shear mixing reactor itself has extremely strong anti-blocking and stable operation capabilities through shearing and engagement even at a large flux and a reaction temperature exceeding 100°C. The subsequent reaction and separation system has no problems of equipment and pipeline blockage in various links after a long period of operation.

[0034] In the present invention, step (2) is carried out in the high shear mixing reactor, and formaldehyde no longer needs to be added from multiple mixers in multiple stages, and a large flow of circulating reaction liquid is no longer needed to dilute the local formaldehyde ratio of the formaldehyde adding part of each mixer. At the same time, multiple heat exchangers are eliminated, and the process flow of condensation of aniline (aniline salt) and formaldehyde is greatly simplified, so that the entire preparation process has the characteristics of no energy waste, simple operation, and stable operation. In addition, the impurity content of the obtained diphenylmethane series amines is extremely low, so that the target product DAM has excellent and stable quality. Moreover, in the preparation method, not only does the reaction liquid before, during and after the high shear mixing reactor not need to be cooled, but even if entering the subsequent step (3), no heat transfer measures are required, thereby achieving effective energy utilization.

[0035] In step (1), aniline as the main raw material and the acidic compound having a catalytic effect are first mixed and reacted. The reaction rate is very fast, and a large amount of reaction heat is released while generating aniline salt. There is no need to remove heat during the reaction process, and the reaction liquid does not need to be cooled. The reaction heat is all used to heat the reaction materials.

[0036] Preferably, the device for the reaction in step (1) can be any mixer or reactor, including but not limited to: a static mixer, a stirred tank, etc.

[0037] Preferably, the acidic compound in step (1) comprises any one of hydrochloric acid, sulfuric acid, phosphoric acid, and methanesulfonic acid, or a combination of at least two thereof, and hydrochloric acid is more preferred.

[0038] Preferably, the mass percentage of HCl in the hydrochloric acid is 25-37%, for example 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35% or 36%, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0039] Preferably, the molar ratio of HCl to aniline in the hydrochloric acid is (0.04-0.5):1, for example, it can be 0.05:1, 0.08:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1 or 0.45:1, and more preferably (0.15-0.4):1.

[0040] Preferably, the reaction time of step (1) is 1-30 s, for example, it can be 2 s, 3 s, 5 s, 7 s, 9 s, 10 s, 11 s, 13 s, 15 s, 17 s or 19 s, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0041] Preferably, the feed flow rate of the aniline salt in step (2) is 0.5-3 m / s, for example, 0.6 m / s, 0.8 m / s, 1 m / s, 1.2 m / s, 1.5 m / s, 1.8 m / s, 2 m / s, 2.2 m / s, 2.5 m / s or 2.8 m / s, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0042] As a preferred technical solution of the present invention, the aniline salt and formaldehyde are directly mixed in a high shear mixing reactor, the pressure drop of the high shear mixing reactor is extremely low, less than 3kPa, the aniline salt is directly transported to the first feed channel of the high shear mixing reactor, and the feed flow rate of the aniline salt is 0.5-3m / s, which can enable the aniline salt and formaldehyde to be fully dispersed and mixed at a microscopic scale. If the flow rate of the aniline salt is too slow, the turbulence in the cavity between the stator and rotor of the high shear mixing reactor is insufficient, affecting the mixing and reaction effect; if the flow rate of the aniline salt is too fast, the time of high-intensity shearing and mixing of the mixed solution (mixed reaction solution of aniline salt and formaldehyde) in the high shear mixing reactor is too short, resulting in limited dispersion and mixing of formaldehyde.

[0043] Preferably, the molar ratio of formaldehyde to aniline in step (2) is (0.3-0.6):1, for example, it can be 0.32:1, 0.35:1, 0.38:1, 0.4:1, 0.42:1, 0.45:1, 0.48:1, 0.5:1, 0.52:1, 0.55:1 or 0.58:1, etc.

[0044] Preferably, the formaldehyde in step (2) is fed into the second feed channel in the form of formaldehyde aqueous solution.

[0045] Preferably, the mass percentage of formaldehyde in the formaldehyde aqueous solution is 30-50%, for example, it can be 32%, 35%, 38%, 40%, 42%, 45% or 48%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0046] Preferably, the feeding pressure of the formaldehyde aqueous solution in step (2) is 6-10 bar A, for example, it can be 6.5 bar A, 7 bar A, 7.5 bar A, 8 bar A, 8.5 bar A, 9 bar A or 9.5 bar A, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively enumerates the specific points included in the range.

[0047] Preferably, the feed flow rate of the formaldehyde aqueous solution in step (2) is 3-8 m / s, for example, it can be 3.5 m / s, 4 m / s, 4.5 m / s, 5 m / s, 5.5 m / s, 6 m / s, 6.5 m / s, 7 m / s or 7.5 m / s, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0048] Preferably, the formaldehyde aqueous solution in step (2) is fed into a second feed channel, the second feed channel comprises a primary feed sub-channel and a secondary feed sub-channel, and the feed molar ratio of the primary feed sub-channel to the secondary feed sub-channel is (1-4):1, for example, it can be 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.5:1 or 3.8:1, etc.

[0049] As a preferred technical solution of the present invention, the formaldehyde is fed from the second feed channel, which specifically includes a primary feed sub-channel and a secondary feed sub-channel. Each level of the feed sub-channel includes two sub-channels arranged opposite to each other, that is, the formaldehyde aqueous solution enters the high shear mixing reactor from four sub-channels and is sprayed in two stages through a porous nozzle. The feed flow rate of the formaldehyde aqueous solution in each spray hole is 3-8 m / s. After the formaldehyde enters the high shear mixing reactor, it is fully dispersed and mixed with the aniline salt in the high-speed shear zone where the stator and rotor device is located. The specific design of the high shear mixing reactor and the feeding method effectively avoid the problems of uneven distribution and local excess of formaldehyde, thereby inhibiting the formation of N-methyl MDA impurities and polymers.

[0050] Preferably, the flow rate of the liquid in the high shear mixing reactor is 0.5-3 m / s, for example, 0.6 m / s, 0.8 m / s, 1 m / s, 1.2 m / s, 1.5 m / s, 1.8 m / s, 2 m / s, 2.2 m / s, 2.5 m / s or 2.8 m / s, and specific values ​​between the above values. Due to space limitations and for simplicity, the present invention no longer exhaustively lists the specific values ​​included in the range. The liquid is a mixed liquid including aniline salt, formaldehyde and the product of the precondensation reaction, that is, the liquid flowing in the high shear mixing reactor.

[0051] Preferably, the rotor speed of the high shear mixing reactor is 800-3000 rpm, for example, it can be 900 rpm, 1000 rpm, 1200 rpm, 1500 rpm, 1800 rpm, 2000 rpm, 2200 rpm, 2500 rpm or 2800 rpm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 1000-2500 rpm is further preferred.

[0052] Preferably, the residence time in the high shear mixing reactor is 0.2-3s, for example, it can be 0.3s, 0.5s, 0.8s, 1s, 1.2s, 1.5s, 1.8s, 2s, 2.2s, 2.5s or 2.8s, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0053] In the preparation method provided by the present invention, no heat transfer is required before, during or after the high shear mixing reactor, and the generated reaction heat can be supplied to the reaction liquid for heating, thereby greatly improving the utilization rate of the reaction heat.

[0054] Preferably, the reaction in step (3) comprises a condensation reaction and a transposition reaction carried out sequentially.

[0055] Preferably, the pressure of the condensation reaction is 2-4 bar A, for example, it can be 2.2 bar A, 2.5 bar A, 2.8 bar A, 3 bar A, 3.2 bar A, 3.5 bar A or 3.8 bar A, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0056] Preferably, the temperature of the condensation reaction is 105-130°C, for example, it can be 106°C, 108°C, 110°C, 112°C, 115°C, 118°C, 120°C, 122°C, 125°C or 128°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0057] Preferably, the condensation reaction time is 20-40 min, for example, it can be 22 min, 25 min, 28 min, 30 min, 32 min, 35 min or 38 min, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0058] Preferably, the condensation reaction is carried out in a pressure-resistant reactor.

[0059] Preferably, the pressure-resistant reactor is provided with a heat exchange tube, and water at 50-80°C is contained in the heat exchange tube; the heat released by the condensation reaction is exchanged through the heat exchange tube to obtain high-grade hot water at 80-100°C.

[0060] Preferably, the heat exchange tube comprises an inner coil tube or an outer coil tube.

[0061] As a preferred technical solution of the present invention, the condensation reaction is carried out in a pressure-resistant reactor, a heat exchange tube is arranged outside the pressure-resistant reactor, the pressure of the pressure-resistant reactor is 2-4 bar A, and 50-80°C hot water is used for heat exchange through the heat exchange tube (inner coil or outer buckle tube or any other method), and the temperature of the pressure-resistant reactor is controlled to be 105-130°C, so that the hot water after heat exchange reaches 80-100°C, and is used as a high-grade hot water resource to supply other supporting devices. The residence time in the pressure-resistant reactor is controlled to be 20-40min to ensure that the formaldehyde reacts fully.

[0062] In the present invention, in order to take into account the stability of the content of each ring and bicyclic isomer in DAM in the actual production process and the adjustment that can meet the expected target, in the condensation reaction of step (3), a design of producing high-grade hot water and controlling the temperature to be stable is set in the pressure-resistant reactor. When the ratio of the reaction raw materials changes, the reaction heat changes accordingly, which will cause the temperature in the pressure-resistant reactor to change. The preparation method provided by the present invention can keep the temperature of the reactor controllable and stable, thereby achieving the stability of the DAM composition. At the same time, the high-grade hot water of 80-100°C produced as a by-product in the condensation stage can produce considerable energy-saving and carbon-reduction benefits under large-scale production equipment.

[0063] Preferably, the temperature of the transposition reaction is 105-130°C, for example, it can be 106°C, 108°C, 110°C, 112°C, 115°C, 118°C, 120°C, 122°C, 125°C or 128°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0064] Preferably, the transposition reaction time is 1.5-4h, for example, it can be 1.8h, 2h, 2.2h, 2.5h, 2.8h, 3h, 3.2h, 3.5h or 3.8h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0065] As a preferred technical solution of the present invention, the process of the transposition reaction (transposition rearrangement process) does not require heating from an additional heat source, and only requires the reaction temperature to be consistent with the temperature of the condensation reaction, and to stay at 105-130°C for 1.5-4h. The reactor for the transposition reaction can be any form such as a kettle reactor, a tower reactor, a horizontal tank reactor, etc.

[0066] Preferably, after the reaction in step (3) is completed, a post-treatment step is also included.

[0067] Preferably, the post-treatment includes the steps of neutralization, water washing and refining.

[0068] Preferably, the preparation method specifically comprises the following steps:

[0069] (1) mixing aniline with hydrochloric acid and reacting to obtain aniline salt; the mass percentage of HCl in the hydrochloric acid is 25-37%, and the molar ratio of HCl to aniline is (0.04-0.5):1;

[0070] (2) performing a pre-condensation reaction between the aniline salt obtained in step (1) and the formaldehyde aqueous solution in the high shear mixing reactor to obtain a reaction solution;

[0071] The molar ratio of formaldehyde to aniline is (0.3-0.6):1;

[0072] The aniline salt is fed from the first feed channel at a feed flow rate of 0.5-3 m / s;

[0073] The formaldehyde aqueous solution is fed from the primary feed sub-channel and the secondary feed sub-channel of the second feed channel, the feed pressure is 6-10 bar A, the feed flow rate is 3-8 m / s, and the feed molar ratio of the primary feed sub-channel to the secondary feed sub-channel is (1-4):1;

[0074] The rotor speed of the high shear mixing reactor is 800-3000 rpm, the flow rate of the liquid in the high shear mixing reactor is 0.5-3 m / s, the residence time is 0.2-3 s, and the obtained reaction liquid is discharged from the discharge channel and enters step (3A);

[0075] (3A) The reaction solution obtained in step (2) is subjected to a condensation reaction in a pressure-resistant reactor to obtain a condensation reaction solution; the pressure in the pressure-resistant reactor is 2-4 bar A, the temperature is 105-130° C., and the residence time is 20-40 min;

[0076] The pressure-resistant reactor is provided with a heat exchange tube, and water at 50-80°C is contained in the heat exchange tube; the heat released by the condensation reaction is exchanged through the heat exchange tube to obtain high-grade hot water at 80-100°C;

[0077] (3B) The condensation reaction liquid obtained in step (3A) is subjected to a metathesis reaction at a temperature of 105-130° C. for 1.5-4 h. The resulting product is subjected to neutralization, water washing and optional purification steps to obtain the diphenylmethane series amines.

[0078] Preferably, the mass percentage of N-methyl MDA impurity in the diphenylmethane series amines is ≤0.1%, for example, it can be 0.001%, 0.005%, 0.008%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08% or 0.09%, etc., further preferably <0.1%, further preferably ≤0.08%, and most preferably ≤0.05%.

[0079] Preferably, the mass percentage of 4,4-MDA in the diphenylmethane series amines is 40-65%, for example, it can be 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60%, 62% or 64%, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 48-60% is further preferred.

[0080] Preferably, the mass percentage of 2,4-MDA in the diphenylmethane series amines is 2-10%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8% or 9%, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range, and 3-8% is further preferred.

[0081] Preferably, the mass percentage of 2,2-MDA in the diphenylmethane series amines is less than 0.5%, for example, it can be 0.05%, 0.08%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4% or 0.45%, and more preferably 0.1-0.3%.

[0082] Compared with the prior art, the present invention has the following beneficial effects:

[0083] (1) In the high shear mixing reactor provided by the present invention, the design of at least two-stage gear array interlocking stator and rotor devices and feed channels enables the materials to be dispersed and mixed at the molecular scale quickly and fully, thereby effectively solving the problem of local excess of materials and inhibiting the occurrence of side reactions. The high shear mixing reactor is used for the preparation of diphenylmethane series amines DAM, and improves the rapid and easy-to-block liquid-liquid reaction system of aniline salt and formaldehyde, so that the N-methyl MDA impurity and polymer content in the target product DAM is reduced to a level significantly ahead of the current industry, solving the pipeline and equipment blockage problem caused by polymers.

[0084] (2) In the preparation method of DAM provided by the present invention, the design and use of the high shear mixing reactor makes it unnecessary to add formaldehyde from multiple mixers in multiple stages, and it is also unnecessary to circulate the reaction liquid with a large flow rate to dilute the local formaldehyde ratio at the formaldehyde adding part of each mixer. At the same time, multiple heat exchangers are eliminated, and the process flow of condensation of aniline and formaldehyde is greatly simplified. The preparation method has the characteristics of no energy waste, simple operation, and smooth operation. The N-methyl MDA impurity content in the obtained DAM is ≤0.05%, and the target product DAM has excellent and stable quality.

[0085] (3) The DAM preparation method can use most of the reaction heat of aniline salt formation and the reaction heat of condensation with formaldehyde to heat the reaction materials, so that the subsequent transposition rearrangement process does not need additional energy, which significantly improves the utilization rate of reaction heat; at the same time, high-grade hot water of 80-100°C is produced as a by-product in the preparation process, which can generate considerable energy-saving and carbon-reduction benefits under large-scale production equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Figure 1 A schematic diagram of the structure of a high shear mixing reactor provided in one specific embodiment of the present invention;

[0087] Figure 2 A schematic structural diagram of a high shear mixing reactor provided in another specific embodiment of the present invention;

[0088] Figure 3 A schematic diagram of the structure of a multi-hole nozzle provided in a specific embodiment of the present invention;

[0089] Among them, 10-shell, 20-rotating shaft, 31-first stage stator-rotor device, 32-second stage stator-rotor device, 33-third stage stator-rotor device, 40-first feed channel, 401-discharge hole, 50-second feed channel, 51-first feed sub-channel, 52-secondary feed sub-channel, 60-discharge channel, 71-injection ring pipe, 72-injection column. DETAILED DESCRIPTION

[0090] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0091] As used herein, the terms "comprises," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0092] "Optional" or "any one" means that the subsequently described matter or event can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0093] The indefinite articles "a" and "an" before the elements or components of the present invention have no limitation on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the quantity obviously refers to the singular form only.

[0094] In the present invention, the features defined as "first" or "second" may include one or more of the features explicitly or implicitly, and are used to distinguish and describe the features, without distinction of order or importance. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0095] In the present invention, the terms "upper", "lower", "inside", "outside", "vertical", "horizontal", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and should not be understood as a limitation on the present invention.

[0096] In the present invention, unless otherwise clearly specified and limited, the terms "connected", "connection" and the like 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above-mentioned terms in the present invention can be understood according to specific circumstances.

[0097] In one embodiment, the structural schematic diagram of the high shear mixing reactor is as follows Figure 1 As shown, it includes: a housing 10 , a rotating shaft 20 , a first-stage stator-rotor device 31 , a second-stage stator-rotor device 32 , a third-stage stator-rotor device 33 , a first feed channel 40 , a second feed channel 50 , and a discharge channel 60 .

[0098] In another specific embodiment, the structural schematic diagram of the high shear mixing reactor is as follows Figure 2 As shown, it includes: a housing 10 , a rotating shaft 20 , a first-stage stator-rotor device 31 , a second-stage stator-rotor device 32 , a first feed channel 40 , a second feed channel 50 , and a discharge channel 60 .

[0099] Figure 1 and Figure 2 In the high shear mixing reactor shown in FIG. 1 , the direction of the rotating shaft 20 is the first direction (i.e. Figure 1 and Figure 2 The horizontal direction shown in the figure), and the direction perpendicular to the first direction is the second direction.

[0100] The first feed channel 40 is arranged in a first direction, and one end thereof extending into the shell is a blind end; a discharge hole 401 is provided on the side wall of the first feed channel 40 near the blind end.

[0101] The second feed channel 50 is arranged in the second direction, and includes a primary feed sub-channel 51 and a secondary feed sub-channel 52 ; the primary feed sub-channel 51 is arranged adjacent to the first-stage stator-rotor device 31 , and the secondary feed sub-channel 52 is arranged adjacent to the second-stage stator-rotor device 32 .

[0102] The high shear mixing reactor is used to prepare diphenylmethane series amines DAM. Aniline salt enters the high shear mixing reactor through the first feed channel 40 and the discharge hole 401; the formaldehyde aqueous solution enters the high shear mixing reactor through the second feed channel (the primary feed sub-channel 51 and the secondary feed sub-channel 52), and is mixed in the high-speed shear area of ​​the rotor and the stator, so that the formaldehyde is quickly dispersed and mixed at the molecular level at an extremely high energy dissipation rate, thereby effectively avoiding uneven formaldehyde dispersion and local excess, inhibiting the occurrence of side reactions, significantly reducing the impurity content of N-methyl MDA, and avoiding the problems of wall adhesion, equipment and pipeline blockage caused by polymers. The reaction liquid in the high shear mixing reactor is passed through the stator-rotor device ( Figure 1 is the third-stage stator-rotor device 33, Figure 2 The second-stage stator-rotor device 32 is sheared and mixed at high speed and then flows out from the discharge channel 60 .

[0103] In a specific embodiment, a multi-hole nozzle is provided at the discharge end of the second feed channel 50. The structural schematic diagram of the multi-hole nozzle is as shown in FIG. Figure 3 As shown, it includes: an injection ring tube 71, 6 injection columns 72 arranged on the injection ring tube 71, each injection column 72 is provided with 3 injection holes, and the opening direction of all the injection holes is toward the stator and rotor gear array ring of the stator and rotor device and is perpendicular to the tangent direction of the gear array ring.

[0104] In one embodiment, the diameter of the nozzle hole is 4 mm. Figure 3 The structure shown.

[0105] In the following specific embodiments of the present invention, raw materials such as aniline (analytical grade), formaldehyde aqueous solution, hydrochloric acid, and caustic soda with a mass concentration of 50% are all produced by Wanhua.

[0106] The composition of DAM was analyzed by gas chromatography (GC) as follows:

[0107] Instrument model: Agilent 7890B;

[0108] Chromatographic column: Agilent HP-5, 530.00μm×30.0m×1.50μm;

[0109] Injection volume: 0.4 μL;

[0110] Column oven: 230℃ for 18min, then increase to 280℃ at 50℃ / min and keep for 30min;

[0111] Carrier gas type: N2, flow rate 1mL / min;

[0112] Detector: FID detector, temperature 300℃.

[0113] Example 1

[0114] This embodiment provides a high shear mixing reactor, the structural schematic diagram of which is shown in FIG. Figure 1 As shown, it includes a shell 10, a rotating shaft 20, a three-stage tooth array interlocking stator and rotor device (along the first direction, respectively: a first-stage stator and rotor device 31, a second-stage stator and rotor device 32, and a third-stage stator and rotor device 33), a first feed channel 40, a second feed channel 50, and a discharge channel 60.

[0115] The first feed channel 40 is arranged in a first direction, and one end thereof extending into the shell is a blind end; a discharge hole 401 is provided on the side wall of the first feed channel 40 near the blind end.

[0116] The second feed channel 50 is arranged in the second direction, and includes a primary feed sub-channel 51 and a secondary feed sub-channel 52 ; the primary feed sub-channel 51 is arranged adjacent to the first-stage stator-rotor device 31 , and the secondary feed sub-channel 52 is arranged adjacent to the second-stage stator-rotor device 32 .

[0117] The three-stage stator-rotor device has the same structure, and the stator-rotor device includes a stator and a rotor. The number of gear rings in the stator and the number of gear rings in the rotor are both 3. The diameter of the outermost gear ring in the stator is 350 mm, and the diameter of the innermost gear ring is 260 mm. The spacing between any adjacent stator teeth and rotor teeth in the stator-rotor device is 10 mm. The tooth thickness of the stator teeth in the stator and the rotor teeth in the rotor are both 5 mm, and the tooth length is both 80 mm.

[0118] In the second feed channel 50, the discharge ends of the primary feed sub-channel 51 and the secondary feed sub-channel 52 are both provided with multi-hole nozzles, and the structural schematic diagram of the multi-hole nozzles is as shown in FIG. Figure 3 As shown, it includes an injection ring pipe 71, 6 injection columns 72 arranged on the injection ring pipe 71, and each injection column 72 is provided with 3 injection holes.

[0119] This embodiment also provides a method for preparing diphenylmethane series amines (DAM), comprising the following steps:

[0120] (1) mixing hydrochloric acid (HCl having a mass percentage of 33%) produced by an MDI device with aniline through a static mixer and reacting the mixture; the residence time of the reaction is 3 seconds to obtain aniline hydrochloride; the molar ratio of HCl to aniline is 0.2:1; and the temperature of the aniline hydrochloride solution rises to 64° C. after the reaction;

[0121] (2) The aniline salt obtained in step (1) and a formaldehyde aqueous solution (the mass percentage of formaldehyde is 40%) are subjected to a pre-condensation reaction in a high shear mixing reactor provided in this embodiment to obtain a reaction solution. The specific method is as follows:

[0122] Aniline hydrochloride is fed into the first feed channel 40 at a flow rate of 2.5 m / s, contacts with the formaldehyde aqueous solution fed from the primary feed sub-channel 51 and sprayed through the porous nozzle, and immediately enters the area where the first-stage stator-rotor device 31 is located for mixing. The molar ratio of formaldehyde to aniline added here is 0.4:1, the feed pressure of the formaldehyde aqueous solution is 8 bar A, and the feed flow rate is 5 m / s; the reaction mixture passing through the area where the first-stage stator-rotor device is located then enters the area where the second-stage stator-rotor device is located, contacts and mixes with the formaldehyde aqueous solution fed from the secondary feed sub-channel 52 and sprayed through the porous nozzle. The molar ratio of formaldehyde to aniline added here is 0.2:1, and the feed pressure and feed flow rate of the formaldehyde aqueous solution are the same as those of the primary feed sub-channel; thereafter, the mixed solution is shear-mixed in the area where the third-stage stator-rotor device is located, and then discharged from the high shear mixing reactor from the discharge channel 60 and enters step (3A);

[0123] In this process, the rotor speed of the high shear mixing reactor is 1000 rpm, the flow rate of the liquid in the high shear mixing reactor is 2.5 m / s, the residence time is 0.8 s, and the obtained reaction liquid temperature is 72° C.

[0124] (3A) The reaction liquid obtained in step (2) is sent to a pressure-resistant reactor for condensation reaction to obtain a condensation reaction liquid; wherein the pressure of the pressure-resistant reactor is 2.5 bar A, 60° C. hot water is used to exchange heat with the reaction liquid through the inner coil in the pressure-resistant reactor, the temperature of the reaction liquid in the pressure-resistant reactor is controlled to be 115° C., and 100° C. high-grade hot water is generated at the same time, and the residence time in the pressure-resistant reactor is 35 min;

[0125] (3B) The condensation reaction liquid obtained in step (3A) is sent to a tower reactor for a transposition reaction, and the outer wall coil of the tower is used for insulation, the reaction temperature is maintained at 115° C., and the residence time is 1.5 h; the product after the transposition reaction is neutralized, washed with water and DAM refined to obtain the DAM.

[0126] The wall adhesion and blockage of the equipment and pipelines in the reaction process and the composition data of DAM are detailed in Table 1.

[0127] Example 2

[0128] This embodiment provides a high shear mixing reactor, the structural schematic diagram of which is shown in FIG. Figure 1 As shown, the only difference between it and Example 1 is that the parameters of the stator-rotor device are different. In this embodiment, the number of gear rings in the stator and the number of gear rings in the rotor are both 2, the diameter of the outermost gear ring in the stator is 290 mm, the diameter of the innermost gear ring is 230 mm, the spacing between any adjacent stator teeth and rotor teeth in the stator-rotor device is 12 mm, the tooth thickness of the stator teeth in the stator and the rotor teeth in the rotor are both 3 mm, and the tooth length is both 100 mm.

[0129] This embodiment also provides a method for preparing DAM, comprising the following steps:

[0130] (1) mixing hydrochloric acid (HCl having a mass percentage of 33%) produced by an MDI device with aniline through a static mixer and reacting the mixture; the residence time of the reaction is 10 seconds to obtain aniline hydrochloride; the molar ratio of HCl to aniline is 0.3:1; and the temperature of the aniline hydrochloride solution after the reaction rises to 75° C.;

[0131] (2) The aniline salt obtained in step (1) and a formaldehyde aqueous solution (the mass percentage of formaldehyde is 45%) are subjected to a pre-condensation reaction in a high shear mixing reactor provided in this embodiment to obtain a reaction solution. The specific method is as follows:

[0132] Aniline hydrochloride is fed into the first feed channel 40 at a flow rate of 1.5 m / s, contacts with the formaldehyde aqueous solution fed from the primary feed sub-channel 51 and sprayed through the porous nozzle, and immediately enters the area where the first-stage stator-rotor device 31 is located for mixing. The molar ratio of formaldehyde to aniline added here is 0.2:1, the feed pressure of the formaldehyde aqueous solution is 10 bar A, and the feed flow rate is 7 m / s; the reaction mixture passing through the area where the first-stage stator-rotor device is located then enters the area where the second-stage stator-rotor device is located, contacts and mixes with the formaldehyde aqueous solution fed from the secondary feed sub-channel 52 and sprayed through the porous nozzle. The molar ratio of formaldehyde to aniline added here is 0.2:1, and the feed pressure and feed flow rate of the formaldehyde aqueous solution are the same as those of the primary feed sub-channel; thereafter, the mixed solution is shear-mixed in the area where the third-stage stator-rotor device is located, and then discharged from the high shear mixing reactor from the discharge channel 60 and enters step (3A);

[0133] In this process, the rotor speed of the high shear mixing reactor is 2000 rpm, the flow rate of the liquid in the high shear mixing reactor is 1.5 m / s, the residence time is 1.3 s, and the obtained reaction liquid temperature is 81° C.;

[0134] (3A) The reaction liquid obtained in step (2) is sent to a pressure-resistant reactor for condensation reaction to obtain a condensation reaction liquid; wherein the pressure of the pressure-resistant reactor is 3.5 bar A, 50° C. hot water is used to exchange heat with the reaction liquid through the inner coil in the pressure-resistant reactor, the temperature of the reaction liquid in the pressure-resistant reactor is controlled to be 110° C., and 100° C. high-grade hot water is generated at the same time, and the residence time in the pressure-resistant reactor is 40 min;

[0135] (3B) The condensation reaction liquid obtained in step (3A) is sent to a tower reactor for a transposition reaction. The outer wall coil of the tower is used for insulation, and the reaction temperature is maintained at 110° C. The residence time is 3.5 h. The product after the transposition reaction is neutralized, washed with water and DAM refined to obtain the DAM.

[0136] The wall adhesion and blockage of the equipment and pipelines in the reaction process and the composition data of DAM are detailed in Table 1.

[0137] Example 3

[0138] This embodiment provides a high shear mixing reactor, the structural schematic diagram of which is shown in FIG. Figure 2 As shown, it includes a housing 10 , a rotating shaft 20 , a two-stage gear array interlocking stator-rotor device (along the first direction, respectively: a first-stage stator-rotor device 31 , a second-stage stator-rotor device 32 ), a first feed channel 40 , a second feed channel 50 , and a discharge channel 60 .

[0139] The first feed channel 40 is arranged in a first direction, and one end thereof extending into the shell is a blind end; a discharge hole 401 is provided on the side wall of the first feed channel 40 near the blind end.

[0140] The second feed channel 50 is arranged in the second direction, and includes a primary feed sub-channel 51 and a secondary feed sub-channel 52 ; the primary feed sub-channel 51 is arranged adjacent to the first-stage stator-rotor device 31 , and the secondary feed sub-channel 52 is arranged adjacent to the second-stage stator-rotor device 32 .

[0141] The two-stage stator-rotor device has the same structure, and the stator-rotor device includes a stator and a rotor. The number of gear rings in the stator and the number of gear rings in the rotor are both 4. The diameter of the outermost gear ring in the stator is 320 mm, and the diameter of the innermost gear ring is 240 mm. The spacing between any adjacent stator teeth and rotor teeth in the stator-rotor device is 6 mm. The tooth thickness of the stator teeth in the stator and the rotor teeth in the rotor are both 4 mm, and the tooth length is both 120 mm.

[0142] In the second feed channel 50, the discharge ends of the primary feed sub-channel 51 and the secondary feed sub-channel 52 are both provided with multi-hole nozzles, and the structural schematic diagram of the multi-hole nozzles is as shown in FIG. Figure 3As shown, it includes an injection ring pipe 71, 6 injection columns 72 arranged on the injection ring pipe 71, and each injection column 72 is provided with 3 injection holes.

[0143] This embodiment also provides a method for preparing DAM, comprising the following steps:

[0144] (1) mixing hydrochloric acid (HCl having a mass percentage of 33%) produced by an MDI device with aniline through a static mixer and reacting the mixture; the residence time of the reaction is 25 seconds to obtain aniline hydrochloride; the molar ratio of HCl to aniline is 0.4:1; and the temperature of the aniline hydrochloride solution rises to 86° C. after the reaction;

[0145] (2) The aniline salt obtained in step (1) and a formaldehyde aqueous solution (the mass percentage of formaldehyde is 35%) are subjected to a pre-condensation reaction in a high shear mixing reactor provided in this embodiment to obtain a reaction solution. The specific method is as follows:

[0146] Aniline hydrochloride is fed into the first feed channel 40 at a flow rate of 0.6 m / s, contacts with the formaldehyde aqueous solution fed from the primary feed sub-channel 51 and sprayed through the porous nozzle, and immediately enters the area where the first-stage stator-rotor device 31 is located for mixing. The molar ratio of formaldehyde to aniline added here is 0.35:1, the feed pressure of the formaldehyde aqueous solution is 7 bar A, and the feed flow rate is 3.5 m / s; the reaction mixture passing through the area where the first-stage stator-rotor device is located then enters the area where the second-stage stator-rotor device is located, contacts and mixes with the formaldehyde aqueous solution fed from the secondary feed sub-channel 52 and sprayed through the porous nozzle, the molar ratio of formaldehyde to aniline added here is 0.09:1, and the feed pressure and feed flow rate of the formaldehyde aqueous solution are the same as those of the primary feed sub-channel; thereafter, the mixed solution is discharged from the high shear mixing reactor from the discharge channel 60 and enters step (3A);

[0147] In this process, the rotor speed of the high shear mixing reactor was 2500 rpm, the flow rate of the liquid in the high shear mixing reactor was 0.6 m / s, the residence time was 2.8 s, and the obtained reaction liquid temperature was 92° C.;

[0148] (3A) The reaction liquid obtained in step (2) is sent to a pressure-resistant reactor for condensation reaction to obtain a condensation reaction liquid; wherein the pressure of the pressure-resistant reactor is 4 bar A, 50° C. hot water is used to exchange heat with the reaction liquid through the inner coil in the pressure-resistant reactor, the temperature of the reaction liquid in the pressure-resistant reactor is controlled to be 125° C., and 90° C. high-grade hot water is generated at the same time, and the residence time in the pressure-resistant reactor is 25 min;

[0149] (3B) The condensation reaction liquid obtained in step (3A) is sent to a tower reactor for a transposition reaction, and the outer wall coil of the tower is used for insulation, the reaction temperature is maintained at 125° C., and the residence time is 1.5 h; the product after the transposition reaction is neutralized, washed with water and DAM refined to obtain the DAM.

[0150] The wall adhesion and blockage of the equipment and pipelines in the reaction process and the composition data of DAM are detailed in Table 1.

[0151] Example 4

[0152] This embodiment provides a high shear mixing reactor, the structural schematic diagram of which is shown in FIG. Figure 2 As shown, it includes a housing 10 , a rotating shaft 20 , a two-stage gear array interlocking stator-rotor device (along the first direction, respectively: a first-stage stator-rotor device 31 , a second-stage stator-rotor device 32 ), a first feed channel 40 , a second feed channel 50 , and a discharge channel 60 .

[0153] The first feed channel 40 is arranged in a first direction, and one end thereof extending into the shell is a blind end; a discharge hole 401 is provided on the side wall of the first feed channel 40 near the blind end.

[0154] The second feed channel 50 is arranged in the second direction, and includes a primary feed sub-channel 51 and a secondary feed sub-channel 52 ; the primary feed sub-channel 51 is arranged adjacent to the first-stage stator-rotor device 31 , and the secondary feed sub-channel 52 is arranged adjacent to the second-stage stator-rotor device 32 .

[0155] The two-stage stator-rotor device has the same structure, and the stator-rotor device includes a stator and a rotor. The number of gear rings in the stator and the number of gear rings in the rotor are both 2 rings. The diameter of the outermost gear ring in the stator is 280 mm, and the diameter of the innermost gear ring is 240 mm. The spacing between any adjacent stator teeth and rotor teeth in the stator-rotor device is 6 mm. The tooth thickness of the stator teeth in the stator and the rotor teeth in the rotor are both 4 mm, and the tooth length is both 120 mm.

[0156] In the second feed channel 50, the discharge ends of the primary feed sub-channel 51 and the secondary feed sub-channel 52 are both provided with multi-hole nozzles, and the structural schematic diagram of the multi-hole nozzles is as shown in FIG. Figure 3 As shown, it includes an injection ring pipe 71, 6 injection columns 72 arranged on the injection ring pipe 71, and each injection column 72 is provided with 3 injection holes.

[0157] This embodiment also provides a method for preparing DAM, comprising the following steps:

[0158] (1) mixing hydrochloric acid (HCl having a mass percentage of 33%) produced by an MDI device with aniline through a static mixer and reacting the mixture; the residence time of the reaction is 20 seconds to obtain aniline hydrochloride; the molar ratio of HCl to aniline is 0.35:1; and the temperature of the aniline hydrochloride solution rises to 81° C. after the reaction;

[0159] (2) The aniline salt obtained in step (1) and a formaldehyde aqueous solution (the mass percentage of formaldehyde is 37%) are subjected to a pre-condensation reaction in a high shear mixing reactor provided in this embodiment to obtain a reaction solution. The specific method is as follows:

[0160] Aniline hydrochloride is fed from the first feed channel 40 at a flow rate of 2.0 m / s, contacts with the formaldehyde aqueous solution fed from the primary feed sub-channel 51 and sprayed through the porous nozzle, and immediately enters the area where the first-stage stator-rotor device 31 is located for mixing. The molar ratio of formaldehyde to aniline added here is 0.35:1, the feed pressure of the formaldehyde aqueous solution is 6.5 bar A, and the feed flow rate is 3.0 m / s; the reaction mixture passing through the area where the first-stage stator-rotor device is located then enters the area where the second-stage stator-rotor device is located, contacts and mixes with the formaldehyde aqueous solution fed from the secondary feed sub-channel 52 and sprayed through the porous nozzle. The molar ratio of formaldehyde to aniline added here is 0.15:1, and the feed pressure and feed flow rate of the formaldehyde aqueous solution are the same as those of the primary feed sub-channel; thereafter, the mixed solution is discharged from the high shear mixing reactor from the discharge channel 60 and enters step (3A);

[0161] In this process, the rotor speed of the high shear mixing reactor is 2000 rpm, the flow rate of the liquid in the high shear mixing reactor is 2.0 m / s, the residence time is 0.8 s, and the temperature of the obtained reaction liquid is 90° C.

[0162] (3A) The reaction liquid obtained in step (2) is sent to a pressure-resistant reactor for condensation reaction to obtain a condensation reaction liquid; wherein the pressure of the pressure-resistant reactor is 3 bar A, 60° C. hot water is used to exchange heat with the reaction liquid through the inner coil in the pressure-resistant reactor, the temperature of the reaction liquid in the pressure-resistant reactor is controlled to be 115° C., and 100° C. high-grade hot water is generated at the same time, and the residence time in the pressure-resistant reactor is 35 min;

[0163] (3B) The condensation reaction liquid obtained in step (3A) is sent to a tower reactor for a transposition reaction, and the outer wall coil of the tower is used for insulation to maintain the reaction temperature at 115° C. and the residence time is 2.0 h; the product after the transposition reaction is neutralized, washed with water and DAM refined to obtain the DAM.

[0164] The wall adhesion and blockage of the equipment and pipelines in the reaction process and the composition data of DAM are detailed in Table 1.

[0165] Comparative Example 1

[0166] This comparative example provides a method for preparing DAM, comprising the following steps:

[0167] (1) mixing hydrochloric acid (HCl having a mass percentage of 33%) produced by an MDI device with aniline through a static mixer and reacting the mixture; the residence time of the reaction is 25 seconds to obtain aniline hydrochloride; the molar ratio of HCl to aniline is 0.4:1; and the temperature of the aniline hydrochloride solution rises to 86° C. after the reaction;

[0168] (2) The aniline salt obtained in step (1) is subjected to a pre-condensation reaction with a formaldehyde aqueous solution (the mass percentage of formaldehyde is 35%) in a supergravity suspended bed reactor (adopting the design of the prior art CN101279923A) to obtain a reaction solution, and the specific method is as follows:

[0169] Aniline hydrochloride is fed into a supergravity suspension bed mixer at a flow rate of 0.6 m / s, and mixed with a formaldehyde aqueous solution injected into the supergravity mixer through a venturi tube, wherein the molar ratio of the added formaldehyde to the aniline is 0.44:1, the injection flow rate is 3.5 m / s, the residence time of the reaction liquid in the supergravity suspension bed mixer is 8 s, and the obtained reaction liquid temperature is 95° C.;

[0170] (3A) The reaction liquid obtained in step (2) is sent to a pressure-resistant reactor for condensation reaction to obtain a condensation reaction liquid; wherein the pressure of the pressure-resistant reactor is 4 bar A, 50° C. hot water is used to exchange heat with the reaction liquid through the inner coil in the pressure-resistant reactor, the temperature of the reaction liquid in the pressure-resistant reactor is controlled to be 125° C., and 90° C. high-grade hot water is generated at the same time, and the residence time in the pressure-resistant reactor is 25 min;

[0171] (3B) The condensation reaction liquid obtained in step (3A) is sent to a tower reactor for a transposition reaction, and the outer wall coil of the tower is used for insulation, the reaction temperature is maintained at 125° C., and the residence time is 1.5 h; the product after the transposition reaction is neutralized, washed with water and DAM refined to obtain the DAM.

[0172] The wall adhesion and blockage of the equipment and pipelines in the reaction process and the composition data of DAM are detailed in Table 1.

[0173] Comparative Example 2

[0174] This comparative example provides a method for preparing DAM, which adopts a traditional process flow of adding formaldehyde in multiple stages, circulating and cooling the pre-condensation liquid in each stage, and referring to Example 5 in the prior art CN101279923A.

[0175] Comparative Example 3

[0176] The high shear mixing reactor used in this comparative example is based on the structure of the high shear mixing reactor provided in Example 4, with reference to the design of the feed port of CN110893328A, the first feed channel is the same as that in Example 4, the first feed channel and the second feed channel are both arranged in the first direction, the second feed channel is coaxial with the first feed channel and is sleeved on the outside of the first feed channel; the structure of the two-stage stator and rotor device is the same as that in Example 4.

[0177] This comparative example provides a method for preparing DAM, comprising the following steps:

[0178] (1) mixing hydrochloric acid (HCl having a mass percentage of 33%) produced by an MDI device with aniline through a static mixer, with a reaction residence time of 20 seconds, to obtain aniline hydrochloride; the molar ratio of HCl to aniline is 0.35:1, and the solution temperature of aniline hydrochloride rises to 81° C. after the reaction;

[0179] (2) The aniline salt obtained in step (1) and a formaldehyde aqueous solution (the mass percentage of formaldehyde is 37%) are subjected to a pre-condensation reaction in a high shear mixing reactor provided in this comparative example to obtain a reaction solution. The specific method is as follows:

[0180] Aniline hydrochloride is fed from the first feed channel at a flow rate of 2.0 m / s, contacts with the formaldehyde aqueous solution fed from the second feed channel, and immediately enters the area where the first-stage stator-rotor device is located for mixing. The molar ratio of formaldehyde to aniline added here is 0.5:1, the feed pressure of the formaldehyde aqueous solution is 6.5 bar A, and the feed flow rate is 3.0 m / s; the reaction mixture passing through the area where the first-stage stator-rotor device is located then enters the area where the second-stage stator-rotor device 32 is located; thereafter, the mixture is discharged from the high shear mixing reactor from the discharge channel and enters step (3A);

[0181] In this process, the rotor speed of the high shear mixing reactor is 2000 rpm, the flow rate of the liquid in the high shear mixing reactor is 2.0 m / s, the residence time is 0.8 s, and the temperature of the obtained reaction liquid is 90° C.

[0182] (3A) The reaction liquid obtained in step (2) is sent to a pressure-resistant reactor for condensation reaction to obtain a condensation reaction liquid; wherein the pressure of the pressure-resistant reactor is 3 bar A, 60° C. hot water is used to exchange heat with the reaction liquid through the inner coil in the pressure-resistant reactor, the temperature of the reaction liquid in the pressure-resistant reactor is controlled to be 115° C., and 100° C. high-grade hot water is generated at the same time, and the residence time in the pressure-resistant reactor is 35 min;

[0183] (3B) The condensation reaction liquid obtained in step (3A) is sent to a tower reactor for a transposition reaction, and the outer wall coil of the tower is used for insulation to maintain the reaction temperature at 115° C. and the residence time is 2.0 h; the product after the transposition reaction is neutralized, washed with water and DAM refined to obtain the DAM.

[0184] The wall adhesion and blockage of the equipment and pipelines in the reaction process and the composition data of DAM are detailed in Table 1.

[0185] Comparative Example 4

[0186] The high shear mixing reactor used in this comparative example is based on the structure of the high shear mixing reactor provided in Example 3, except that the secondary subchannel 52 of the second feed channel is eliminated and only the primary subchannel of the second feed channel is retained as the feed channel for the formaldehyde aqueous solution. The rest of the structure is exactly the same as that in Example 3.

[0187] This comparative example provides a method for preparing DAM, comprising the following steps:

[0188] (1) mixing hydrochloric acid (HCl having a mass percentage of 33%) produced by an MDI device with aniline through a static mixer, with a reaction residence time of 25 seconds, to obtain aniline hydrochloride; the molar ratio of HCl to aniline is 0.4:1, and the solution temperature of aniline hydrochloride rises to 86° C. after the reaction;

[0189] (2) The aniline salt obtained in step (1) and a formaldehyde aqueous solution (the mass percentage of formaldehyde is 35%) are subjected to a pre-condensation reaction in a high shear mixing reactor in this comparative example to obtain a reaction solution. The specific method is as follows:

[0190] Aniline hydrochloride is fed into the first feed channel 40 at a flow rate of 0.6 m / s, contacts with the formaldehyde aqueous solution fed from the first feed sub-channel 51 and sprayed in through the porous nozzle, and immediately enters the area where the first-stage stator-rotor device 31 is located for mixing. The molar ratio of formaldehyde to aniline added here is 0.44:1, the feed pressure of the formaldehyde aqueous solution is 7 bar A, and the feed flow rate is 3.5 m / s; the reaction mixture passing through the area where the first-stage stator-rotor device is located then enters the area where the second-stage stator-rotor device is located, and then the mixture is discharged from the high shear mixing reactor from the discharge channel 60 and enters step (3A);

[0191] In this process, the rotor speed of the high shear mixing reactor was 2500 rpm, the flow rate of the liquid in the high shear mixing reactor was 0.6 m / s, the residence time was 2.8 s, and the obtained reaction liquid temperature was 92° C.;

[0192] (3A) The reaction liquid obtained in step (2) is sent to a pressure-resistant reactor for condensation reaction to obtain a condensation reaction liquid; wherein the pressure of the pressure-resistant reactor is 4 bar A, 50° C. hot water is used to exchange heat with the reaction liquid through the inner coil in the pressure-resistant reactor, the temperature of the reaction liquid in the pressure-resistant reactor is controlled to be 125° C., and 90° C. high-grade hot water is generated at the same time, and the residence time in the pressure-resistant reactor is 25 min;

[0193] (3B) The condensation reaction liquid obtained in step (3A) is sent to a tower reactor for a transposition reaction, and the outer wall coil of the tower is used for insulation, the reaction temperature is maintained at 125° C., and the residence time is 1.5 h; the product after the transposition reaction is neutralized, washed with water and DAM refined to obtain the DAM.

[0194] The wall adhesion and blockage of the equipment and pipelines in the reaction process and the composition data of DAM are detailed in Table 1.

[0195] The composition data of DAM obtained in Examples 1-4 and Comparative Examples 1-4, and the wall adhesion and blockage of the equipment and pipelines in the reaction process are shown in Table 1; the content (%) of each component in Table 1 is the mass percentage of the substance in DAM; the wall adhesion and blockage of the equipment and pipelines are characterized by the frequency of cleaning of the equipment and pipelines due to blockage.

[0196] Table 1

[0197]

[0198] Combined with the test results of Table 1, it can be seen that in the preparation method of diphenylmethane series amines DAM provided by the present invention, after adopting a high shear mixing reactor with a specific structure, the equipment and pipelines will basically not have high polymer wall hanging and clogging. At the same time, the dicyclic isomers in DAM can meet the market demand for products, especially the N-methyl MDA impurity content in DAM is ≤0.05%, as low as 0.01-0.04%, which has dropped to the lowest level in history, and has a significant effect on improving the quality of downstream MDI and stable operation. In Comparative Example 1, even if the supergravity suspended bed reactor with better mixing effect in the past has a sharp increase in N-methyl impurity content under the simplified condensation reaction process of the present invention, the situation of high polymer blocking the equipment pipeline occurs frequently. In Comparative Example 2, the embodiment in the prior art CN101279923A is cited. Under a more complex reaction process, including the large circulation of the reaction liquid and the removal of the reaction heat, the reaction quality is relatively stable and the clogging situation is alleviated, but there is still a large gap compared with the effect of the method of the present invention. Although Comparative Examples 3 and 4 contain multi-stage stator-rotor devices, the second feed channel for feeding the formaldehyde aqueous solution has only one stage. Therefore, there are different degrees of uneven formaldehyde dispersion and local formaldehyde excess, and the side reaction cannot be effectively suppressed, resulting in a high content of N-methyl MDA impurities in the product. On average, equipment and pipeline blockages occur every two months.

[0199] In summary, the present invention not only effectively controls the generation of undesirable impurities such as N-methyl MDA and polymers during the reaction process, but also greatly simplifies the process, uses the reaction heat of the first two steps as the heat source for the heat required in the translocation stage, and produces high-grade hot water as a by-product, thereby effectively reducing the production cost of DAM and improving the industrial production efficiency.

[0200] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the high shear mixing reactor and the method for preparing diphenylmethane series amines of the present invention, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A high shear mixing reactor, characterized in that: The high shear mixing reactor comprises: a shell, a rotating shaft, a stator-rotor device of at least two stages, a first feed channel, a second feed channel and a discharge channel; the stator and the rotor in the stator-rotor device are engaged; The direction of the rotation axis is taken as a first direction, and the direction perpendicular to the first direction is taken as a second direction; The at least two-stage stator-rotor device comprises a first-stage stator-rotor device and a second-stage stator-rotor device arranged in sequence along the first direction; The first feed channel is arranged in a first direction, and one end thereof extending into the housing is a blind end; a discharge hole is arranged on a side wall of the first feed channel near the blind end; The second feed channel is arranged in the second direction, and includes a primary feed sub-channel and a secondary feed sub-channel; the primary feed sub-channel is arranged adjacent to the first-stage stator-rotor device, and the secondary feed sub-channel is arranged adjacent to the second-stage stator-rotor device.

2. The high shear mixing reactor according to claim 1, characterized in that The number of gear rings in the stator is the same as the number of gear rings in the rotor, and the number of gear rings in the stator is 2-4.

3. The high shear mixing reactor according to claim 2, characterized in that The distance between the innermost gear ring and the outermost gear ring in the stator is 60-100 mm.

4. The high shear mixing reactor according to claim 2, characterized in that The diameter of the outermost gear ring in the stator is 280-360 mm.

5. The high shear mixing reactor according to claim 2, characterized in that The stator teeth in the stator and the rotor teeth in the rotor have the same tooth length; the tooth length is 80-120 mm.

6. The high shear mixing reactor according to claim 5, characterized in that The tooth thickness of the stator teeth in the stator and the rotor teeth in the rotor are independently 1-6 mm.

7. The high shear mixing reactor according to claim 2, characterized in that The distance between any adjacent stator teeth and rotor teeth in the stator-rotor device is 5-15 mm.

8. The high shear mixing reactor according to claim 1, characterized in that A multi-hole nozzle is provided at the discharge end of the second feed channel, and the multi-hole nozzle comprises a spray ring tube and at least two spray columns arranged on the spray ring tube; each of the spray columns is independently provided with 2-6 spray holes.

9. The high shear mixing reactor according to claim 8, characterized in that The number of the injection columns arranged on the injection ring pipe is 4-8.

10. The high shear mixing reactor according to claim 8, characterized in that The diameter of the spray hole is 3-7 mm.

11. Use of the high shear mixing reactor according to any one of claims 1 to 10 in the preparation of amine compounds or isocyanate compounds.

12. A method for preparing diphenylmethane series amines, characterized in that: The preparation method comprises the following steps: (1) Aniline reacts with an acidic compound to obtain an aniline salt; (2) performing a pre-condensation reaction of the aniline salt obtained in step (1) with formaldehyde to obtain a reaction solution; (3) reacting the reaction solution obtained in step (2) to obtain the diphenylmethane series amines; Step (2) is carried out in a high shear mixing reactor as described in any one of claims 1 to 10, the aniline salt is fed from the first feed channel, the formaldehyde is fed from the second feed channel, and the obtained reaction solution is discharged from the discharge channel and enters step (3).

13. The preparation method according to claim 12, characterized in that: The acidic compound in step (1) includes any one of hydrochloric acid, sulfuric acid, phosphoric acid, and methanesulfonic acid, or a combination of at least two thereof.

14. The preparation method according to claim 13, characterized in that: The acidic compound in step (1) includes hydrochloric acid.

15. The preparation method according to claim 13, characterized in that: The mass percentage of HCl in the hydrochloric acid is 25-37%.

16. The preparation method according to claim 13, characterized in that: The molar ratio of HCl to aniline in the hydrochloric acid is (0.04-0.5):

1.

17. The preparation method according to claim 12, characterized in that: The reaction time of step (1) is 1-30s.

18. The preparation method according to claim 12, characterized in that: The feed flow rate of the aniline salt in step (2) is 0.5-3 m / s.

19. The preparation method according to claim 12, characterized in that: The molar ratio of formaldehyde to aniline in step (2) is (0.3-0.6):

1.

20. The preparation method according to claim 12, characterized in that: In step (2), the formaldehyde is fed into the second feed channel in the form of formaldehyde aqueous solution.

21. The preparation method according to claim 20, characterized in that: The mass percentage of formaldehyde in the formaldehyde aqueous solution is 30-50%.

22. The preparation method according to claim 20, characterized in that: The feeding pressure of the formaldehyde aqueous solution in step (2) is 6-10 bar A.

23. The preparation method according to claim 20, characterized in that: The feed flow rate of the formaldehyde aqueous solution in step (2) is 3-8 m / s.

24. The preparation method according to claim 20, characterized in that: In step (2), the formaldehyde aqueous solution is fed into the second feed channel, and the second feed channel includes a primary feed sub-channel and a secondary feed sub-channel, and the feed molar ratio of the primary feed sub-channel to the secondary feed sub-channel is (1-4):

1.

25. The preparation method according to claim 12, characterized in that: The rotor speed of the high shear mixing reactor is 800-3000 rpm.

26. The preparation method according to claim 12, characterized in that: The flow rate of the liquid in the high shear mixing reactor is 0.5-3 m / s.

27. The preparation method according to claim 12, characterized in that: The residence time in the high shear mixing reactor is 0.2-3 s.

28. The preparation method according to claim 12, characterized in that: The reaction in step (3) comprises a condensation reaction and a transposition reaction which are carried out in sequence.

29. The preparation method according to claim 28, characterized in that: The condensation reaction pressure is 2-4 bar A.

30. The preparation method according to claim 28, characterized in that: The temperature of the condensation reaction is 105-130°C.

31. The preparation method according to claim 28, characterized in that: The condensation reaction time is 20-40 minutes.

32. The preparation method according to claim 28, characterized in that: The condensation reaction is carried out in a pressure-resistant reactor.

33. The preparation method according to claim 32, characterized in that: The pressure-resistant reactor is provided with a heat exchange tube, and water at 50-80° C. is contained in the heat exchange tube; the heat released by the condensation reaction is exchanged through the heat exchange tube to obtain high-grade hot water at 80-100° C.

34. The preparation method according to claim 28, characterized in that: The temperature of the metathesis reaction is 105-130°C.

35. The preparation method according to claim 28, characterized in that: The translocation reaction time is 1.5-4h.

36. The preparation method according to claim 12, characterized in that: After the reaction in step (3) is completed, a post-treatment step is also included.

37. The preparation method according to claim 36, characterized in that: The post-treatment includes the steps of neutralization, water washing and refining.

38. The preparation method according to claim 12, characterized in that: The preparation method comprises the following steps: (1) mixing aniline with hydrochloric acid and reacting to obtain aniline salt; the mass percentage of HCl in the hydrochloric acid is 25-37%, and the molar ratio of HCl to aniline is (0.04-0.5):1; (2) performing a pre-condensation reaction between the aniline salt obtained in step (1) and the formaldehyde aqueous solution in the high shear mixing reactor to obtain a reaction solution; The molar ratio of formaldehyde to aniline is (0.3-0.6):1; The aniline salt is fed from the first feed channel at a feed flow rate of 0.5-3 m / s; The formaldehyde aqueous solution is fed from the primary feed sub-channel and the secondary feed sub-channel of the second feed channel, the feed pressure is 6-10 bar A, the feed flow rate is 3-8 m / s, and the feed molar ratio of the primary feed sub-channel to the secondary feed sub-channel is (1-4):1; The rotor speed of the high shear mixing reactor is 800-3000 rpm, the flow rate of the liquid in the high shear mixing reactor is 0.5-3 m / s, the residence time is 0.2-3 s, and the obtained reaction liquid is discharged from the discharge channel and enters step (3A); (3A) The reaction solution obtained in step (2) is subjected to a condensation reaction in a pressure-resistant reactor to obtain a condensation reaction solution; the pressure in the pressure-resistant reactor is 2-4 bar A, the temperature is 105-130° C., and the residence time is 20-40 min; The pressure-resistant reactor is provided with a heat exchange tube outside, and water at 50-80°C is contained in the heat exchange tube; the heat released by the condensation reaction is exchanged through the heat exchange tube to obtain high-grade hot water at 80-100°C; (3B) The condensation reaction liquid obtained in step (3A) is subjected to a metathesis reaction at a temperature of 105-130° C. for 1.5-4 h. The resulting product is subjected to neutralization, water washing and optional purification steps to obtain the diphenylmethane series amines.

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