Preparation method of diamine and polyamine of diphenylmethane series

Abstract

The present invention provides a method for preparing diphenylmethane series diamines and polyamines (DAM), the method comprising the step of reacting aniline with formaldehyde in the presence of an acid catalyst, in which an aniline stream and a formaldehyde stream are respectively introduced into a reactor from respective runners; the aniline material flow and the formaldehyde material flow respectively meet the characteristic parameter epsilon less than or equal to 5. According to the method, the materials are uniformly dispersed, the mixing effect is good, the generation amount of N-methyl impurities and high polymers can be reduced, the problem of blockage of a material flow channel is solved, stable and long-period operation of a DAM production process is realized, and the production efficiency and benefits are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of chemical preparation, and particularly relates to a preparation method of diamines and polyamines (DAM) in the diphenylmethane series. BACKGROUND

[0002] The diamines and polyamines (DAM) in the diphenylmethane series refer to amines and mixtures of amines having the following structure type:

[0003]

[0004] In the formula, n represents a natural number greater than or equal to 0, n = 0 is called diamino diphenylmethane, and is simply referred to as diamine; n > 0 is called polyamine-based polyphenylmethane, and is simply referred to as polyamine; and a mixture of the two types is called diamine and polyamine in the diamino diphenylmethane series. After all NH2 groups in DAM are replaced by NCO groups, the resulting product is diamino diphenylmethane series diisocyanate, diamino diphenylmethane series polyisocyanate, or polyimino polyphenylene polymethylene polyisocyanate, or diamino diphenylmethane series diisocyanate and polyisocyanate (hereinafter referred to as MDI), which are used to produce polyurethane.

[0005] In the art, the preparation method of DAM is generally known and described in many published patents and publications, such as US20090240077A1 and WO1999040059A1. DAM is prepared by a continuous, semi-continuous or discontinuous reaction process, typically using aniline to react with hydrochloric acid to form aniline hydrochloride, and then adding formaldehyde in a reactor to form DAM hydrochloride. After neutralization, water washing, and separation of the organic phase and the inorganic phase, a crude DAM is obtained, which is refined to obtain DAM, and then subjected to a phosgenation reaction to form monomer or polymeric MDI.

[0006] In the traditional large-scale industrial production process, high polymers are easily generated due to unreasonable design of the reactor for (pre) condensation reaction of formaldehyde and aniline, poor mixing effect of formaldehyde and aniline, and poor dispersion effect of formaldehyde, thereby causing blockage of the reactor cavity and the material flow channel, increase of N-methyl impurity content in the DAM product, and frequent shutdown for cleaning of the reactor blockage, which further leads to increase of manual operation amount, inability to ensure high and stable production of DAM product, and limitation of production efficiency and benefit of the enterprise.

[0007] In view of these problems existing in the preparation method of DAM, the research work at home and abroad at present all focuses on strengthening the mixing effect of the multiple material streams after discharging to reduce the generation amount of N-methyl impurities and high polymers, so as to solve the problem of material flow channel blockage and realize stable and long-period operation of the DAM production process, and improve the production efficiency and benefit.

[0008] Although the methods disclosed in the above patents solve the problem of poor mixing effect of the mixed materials in the reactor, in actual application, the flow channels of the materials in the reactor are still not smooth, and the materials are reversely mixed, which leads to local dispersion of the material flow channels and limited mixing effect, and further triggers the generation of high polymers from the materials in the reactor, resulting in blockage and increase of N-methyl impurities, increases the frequency of manual cleaning of the reactor blockage, reduces the product quality, and restricts the production efficiency and benefit of the enterprise. Therefore, it is urgent to develop a DAM preparation process that can meet the long-period stable operation of the reactor. SUMMARY

[0009] In view of the above problems existing in the prior art, the purpose of the present application is to provide a method for stably preparing DAM for a long period, which has uniform material dispersion and good mixing effect, can reduce the generation amount of N-methyl impurities and high polymers, solve the problem of material flow channel blockage, realize stable and long-period operation of the DAM production process, and improve the production efficiency and benefit.

[0010] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0011] The present application provides a preparation method of diamine and polyamine (DAM) of diphenylmethane series, which comprises the step of reacting aniline with formaldehyde in the presence of an acid catalyst, wherein the aniline stream and the formaldehyde stream are respectively introduced into the reactor from their respective flow channels;

[0012] The aniline stream and the formaldehyde stream respectively satisfy the characteristic parameter ε≤5, and the characteristic parameter ε is calculated by formula (1):

[0013]

[0014] In formula (1), D is the diameter of the flow channel, mm; V is the flow rate of the stream in the flow channel, m / s; μ is the viscosity of the stream, cP; and ΔP is the pressure difference between the flow channel pressure and the back pressure of the flow channel, kPa.

[0015] In one embodiment, the characteristic parameter ε of the aniline stream and the formaldehyde stream entering the reactor is controlled to be ≤ 5, preferably ≤ 3, more preferably ≤ 2, and further preferably ≤ 1, respectively.

[0016] In one embodiment, the number of flow channels for each of the aniline stream and the formaldehyde stream is at least one, and can also be two or more.

[0017] In one embodiment, the reaction of aniline with formaldehyde in the presence of an acid catalyst includes condensation reaction, pre-condensation reaction, and the like.

[0018] In one embodiment, the aniline stream is an amine group (-NH2) containing stream, and the composition thereof comprises one or more of aniline, aniline acid salt, pre-condensation reaction liquid of aniline and formaldehyde, condensation reaction liquid of aniline and formaldehyde, and the like; that is, the aniline stream can be a pure aniline stream, an aniline acid salt stream, a pre-condensation reaction liquid stream of aniline and formaldehyde, a condensation reaction liquid stream of aniline and formaldehyde, or any combination thereof; wherein the aniline acid salt stream is a stream generated by pre-mixing aniline and an acid catalyst; and wherein the (pre) condensation reaction liquid stream of aniline and formaldehyde is a reaction liquid stream generated by (pre) condensation reaction of aniline and formaldehyde in the presence of an acid catalyst.

[0019] In practical applications, one specific embodiment is to pre-mix the aniline and the acid catalyst to generate aniline acid salt, and then use it as the aniline stream, together with the formaldehyde stream from the respective flow channels, to enter the reactor to perform (pre) condensation reaction.

[0020] In practical applications, one specific embodiment is to pre-mix the aniline and the acid catalyst to generate aniline acid salt, and mix it with optional partial reflux of the pre-condensation reaction liquid of aniline and formaldehyde, the condensation reaction liquid of aniline and formaldehyde, and then use it as the aniline stream, together with the formaldehyde stream from the respective flow channels, to enter the reactor to perform (pre) condensation reaction.

[0021] Currently in the production process of preparing DAM with aniline and formaldehyde as raw materials, the local high concentration of formaldehyde can lead to the generation of multi (large) ring substances, i.e. high polymers, and N-methyl impurities can also be generated in the process. The existing technology focuses on strengthening the mixing effect of the multiple material discharges in the reactor chamber to reduce the product high polymer and the reactor blockage frequency, and ignores the relevance study of the material characteristics. The present inventors found that the material flow characteristics are related to the reactor internal material mixing effect and impurity generation, and improper control can easily cause the reactor material flow channel to be not smooth, leading to local dispersion of the material flow channel, limited mixing effect, and then triggering the reactor material to generate high polymers and increase the N-methyl content, increasing the frequency of manual cleaning of the reactor blockage and reducing the product quality.

[0022] The present inventors further found that controlling the related parameters such as the flow characteristics (such as viscosity, speed) of the feed stream in the reactor, the size of the flow channel, and the pressure difference within a certain range can realize long-period stable operation of the reactor. On this basis, by simulating the fluid flow model of aniline and formaldehyde feed, the specific related parameters of the feed flow are screened out, a fitting formula (1) is established according to the relationship between the viscosity, flow rate, flow channel size and pressure difference parameters, and the related characteristic parameter ε is obtained. When the characteristic parameter ε is not greater than 5, the material dispersion effect can be optimized, the impurity generation amount can be reduced, and the material flow channel blockage problem can be solved.

[0023] In an embodiment, the preparation method of the present application, the reaction of aniline and formaldehyde in the presence of an acid catalyst is a pre-condensation reaction, specifically, a step of pre-condensation reaction of aniline and formaldehyde in the presence of an acid catalyst to generate a pre-condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines (DAM).

[0024] In an embodiment, the preparation method of the present application, further comprises a step of reacting aniline with an acid catalyst to generate aniline acid salt.

[0025] In an embodiment, the preparation method of the present application, further comprises a step of pre-condensation reaction of the pre-condensation reaction liquid to generate a condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines (DAM).

[0026] In an embodiment, the preparation method of the present application, further comprises a step of rearrangement reaction of the condensation reaction liquid to generate a mixture containing diamino diphenyl methane series diamines and polyamines (DAM).

[0027] In an embodiment, the preparation method of the present application, further comprises a step of neutralizing and separating the mixture containing diamino diphenyl methane series diamines and polyamines to obtain crude diamino diphenyl methane series diamines and polyamines (DAM);

[0028] and, optionally, a step of refining a crude diamino diphenyl methane series diamine and polyamine (DAM) to obtain a DAM product.

[0029] In one embodiment, the method for preparing a diamino diphenyl methane series diamine and polyamine (DAM) according to the present application comprises the following steps:

[0030] 1) mixing aniline and an acid catalyst to perform a salt formation reaction to obtain an aniline stream containing aniline acid salt;

[0031] 2) feeding the aniline stream containing aniline acid salt obtained in step 1) and a formaldehyde stream into a pre-condensation reactor respectively from their own flow channels to perform a pre-condensation reaction to obtain a pre-condensation reaction liquid containing a diamino diphenyl methane series diamine and polyamine (DAM);

[0032] 3) feeding the pre-condensation reaction liquid obtained in step 2) into a condensation reactor to perform a condensation reaction to obtain a condensation reaction liquid containing a diamino diphenyl methane series diamine and polyamine (DAM);

[0033] 4) performing a rearrangement reaction on the condensation reaction liquid obtained in step 3) to obtain a mixture containing a diamino diphenyl methane series diamine and polyamine (DAM);

[0034] 5) adding a base to the mixture obtained in step 4) to perform a neutralization reaction, and after phase separation, obtaining an organic phase containing a diamino diphenyl methane series diamine and polyamine (DAM), and then performing a water washing and distillation to obtain a diamino diphenyl methane series diamine and polyamine product.

[0035] In some specific examples, the molar ratio of aniline to acid catalyst in step 1) is 1:0.01-0.80, preferably 1:0.05-0.40, and more preferably 1:0.10-0.30, wherein the molar amount of the acid catalyst is calculated based on H + .

[0036] In some specific examples, the acid catalyst in step 1) is selected from one or more of an organic acid, an inorganic acid, and a solid acid, preferably hydrochloric acid, and more preferably hydrochloric acid with a concentration of 30-37 wt%.

[0037] In some specific examples, the reaction temperature of the salt formation reaction in step 1) is 20-100°C, preferably 35-95°C, and the reaction time is 0.01-300 s, preferably 0.05-60 s.

[0038] In some specific examples, the molar ratio of formaldehyde to aniline in step 1) in step 2) is 0.20-0.85:1, preferably 0.30-0.60:1, and more preferably 0.30-0.50:1.

[0039] In some specific examples, the reaction temperature of the pre-condensation reaction in step 2) is 20-180℃, preferably 35-150℃, more preferably 60-95℃, and the reaction time is 0.01-300s, preferably 0.05-60s.

[0040] In some specific examples, the reaction temperature of the condensation reaction in step 3) is 20-180℃, preferably 35-150℃, more preferably 60-95℃, and the reaction time is 0.01-300min, preferably 15-240min.

[0041] In some specific examples, the reaction temperature of the transposition rearrangement reaction in step 4) is 35-180℃, preferably 60-150℃, and the reaction time is 1-10h, preferably 2-5h.

[0042] In some specific examples, the base in step 5) is selected from one or more of alkali metal hydroxides and alkaline earth metal hydroxides, preferably one or more of sodium hydroxide and potassium hydroxide.

[0043] Preferably, the base is formulated into an aqueous base solution before being added to the mixture for neutralization, and more preferably, the aqueous base solution is a sodium hydroxide solution; preferably, the mass content of the base in the aqueous base solution is 20-55%, preferably 32-50%.

[0044] In some specific examples, the amount of the base in step 5) is 1.0-3.0 times the amount of the acid catalyst in step 2), based on the molar ratio of OH - and H + , preferably 1.01-1.30:1.

[0045] In some specific examples, the reaction temperature of the neutralization in step 5) is 60-150℃, and the reaction time is 0.5-90min.

[0046] Compared with the prior art, the technical scheme of the present application has the beneficial effects that:

[0047] By controlling the correlation characteristic parameters ε of the viscosity, flow rate, flow channel size and pressure difference of the aniline stream and the formaldehyde stream entering the reactor within a certain range during the reaction process, the present application can reduce the generation amount of N-methyl impurities, polymers and other impurities, solve the problem of material flow channel blockage, improve the product quality, and realize stable DAM production process and long-period operation. DETAILED DESCRIPTION

[0048] The following will be described in detail the content of the present application. It should be noted that the endpoints of the ranges and any values disclosed in this specification are not limited to the precise values stated. These ranges and values should be interpreted as approximately between the stated values. For numerical ranges, the endpoints are included between each respective range, the endpoints are included with each respective range, and the individual points are included between each respective range, and these numerical ranges are to be construed as specifically disclosed herein.

[0049] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0050] In the present application, "one or more" means any one, any two or any two or more of the listed items.

[0051] In the present application, "optional" means that the combination of the listed items is included / not included in the technical solution.

[0052] In the present application, in the technical features described in an open-ended manner, both the closed technical solution consisting of the listed features and the open technical solution containing the listed features are included.

[0053] In the present application, when referring to a numerical interval, both endpoints of the numerical interval are included unless otherwise specified.

[0054] In the present application, when referring to a percentage concentration, the final concentration is meant unless otherwise specified. The final concentration refers to the proportion of the added ingredient in the system after the ingredient is added.

[0055] In the present application, when referring to a temperature parameter, it is allowed to be treated at a constant temperature or within a certain temperature range unless otherwise specified. The constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument.

[0056] In the present application, a preparation method of diamines and polyamines (DAM) of diphenylmethane series is provided, which comprises the step of reaction of aniline with formaldehyde in the presence of an acid catalyst, wherein the aniline stream and the formaldehyde stream are respectively introduced into the reactor from the respective flow channels; optionally, the reaction of aniline with formaldehyde in the presence of an acid catalyst comprises condensation reaction, pre-condensation reaction, etc. In some embodiments, in particular, the step of pre-condensation reaction of aniline with formaldehyde in the presence of an acid catalyst to generate a pre-condensation reaction liquid containing diamines and polyamines (DAM) of diphenylmethane series is included, wherein the aniline stream is introduced into the reactor from the aniline flow channel, the formaldehyde stream is introduced into the reactor from the formaldehyde flow channel, and in particular, the number of flow channels for the aniline stream and the formaldehyde stream is not particularly limited, and is at least one, or two or more, such as 1, 2, 3, 5, 10, 15, 20, 30 or more, etc.

[0057] In this step, the aniline hydrochloride stream and the formaldehyde stream satisfy the characteristic parameter ε≤5, which is calculated by formula (1):

[0058]

[0059] In formula (1), D is the diameter of the flow channel, mm; V is the flow rate of the stream in the flow channel, m / s; μ is the viscosity of the stream, cP; and ΔP is the pressure difference between the flow channel pressure and the flow channel back pressure, kPa.

[0060] In formula (1), the stream refers to the feed stream introduced into the reactor (such as a pre-condensation reactor or a condensation reactor), including the aniline stream and the formaldehyde stream, which correspond to the aniline feed stream and the formaldehyde feed stream introduced into the reactor from the respective flow channels, respectively.

[0061] In formula (1), ΔP is the pressure difference, which is calculated by the difference between the flow channel pressure and the flow channel back pressure; generally, the flow channel pressure is greater than the flow channel back pressure.

[0062] According to the general understanding in the field, the flow channel pressure refers to the pressure generated by the movement of fluid when the fluid passes through the pipe or flow channel. The flow channel pressure can be directly measured by a pressure sensor placed at an appropriate position of the flow channel to monitor the flow channel pressure in real time. The flow channel back pressure refers to the reverse pressure formed after the fluid encounters resistance during flow. The flow channel back pressure is the outlet pressure of the flow channel. The flow channel back pressure is directly measured by a pressure sensor placed at an appropriate position of the flow channel outlet, such as the reactor cavity, to monitor the flow channel back pressure in real time.

[0063] It should be noted that the above formula (1) represents only the numerical relationship between the above parameters D, V, μ, ΔP, and there is no corresponding relationship between the units of the data on both sides of the formula. The characteristic parameter ε of the aniline stream and the formaldehyde stream entering the reactor in this step is ≤5, which can make the material disperse uniformly, has good mixing effect, reduce the generation amount of N-methyl, polymer and other impurities, solve the problem of material flow channel blockage, realize the stable DAM production process, long period operation, improve the production efficiency and benefit.

[0064] It should also be noted that the present application does not specifically limit the value range of each of the parameters D, V, μ, ΔP in the above formula (1), and each parameter can be complementary to each other. After being substituted into formula (1), the value of the characteristic parameter ε ≤5 can be obtained, and the effect of the present application can be theoretically achieved, which has wide applicability.

[0065] Specifically, in the preparation method of the present application, the characteristic parameter ε of the aniline stream and the formaldehyde stream entering the reactor is ≤5, including but not limited to 0.0001, 0.001, 0.01, 0.1, 0.2, 0.5, 0.8, 1.0, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or a range formed by any two of them, such as controlling the characteristic parameter ε ≤5, ε ≤3, ε ≤2 or ε ≤1, etc.; in a more preferred embodiment, the characteristic parameter ε is controlled to be ≤3, preferably, for example, the characteristic parameter ε is controlled to be ≤2; preferably, the characteristic parameter ε is controlled to be ≤1, such as 0.1, 0.01, 0.001, 0.0001, 0.00001, etc., and the characteristic parameter ε tends to 0, which can more significantly reduce the content of N-methyl, polymer and other impurities, and reduce the risk of material flow channel blockage. In the present application, the aniline stream can be understood as a stream containing amine group (-NH2), which is composed of one or more of aniline, aniline salt, pre-condensation reaction liquid of aniline and formaldehyde, and condensation reaction liquid of aniline and formaldehyde;

[0066] In some optional embodiments, a conventional operation is to pre-mix aniline and acid catalyst in a static mixer or the like to generate a corresponding aniline salt; that is, the aniline stream can be a pure aniline stream or an aniline stream containing aniline salt; wherein the aniline stream containing aniline salt can realize simultaneous feeding of aniline and acid catalyst, specifically, aniline and acid catalyst are pre-mixed to generate a salt reaction to obtain a mixture containing aniline salt, which is then used as an aniline stream entering the reactor. In the actual operation process of some embodiments, aniline and acid catalyst are pre-mixed to generate aniline hydrochloride, which is then used as an aniline stream, and the formaldehyde stream is introduced into the reactor from a different flow channel for reaction.

[0067] In some optional embodiments, a conventional operation is to perform partial reflux on the reaction liquid stream generated by the (pre) condensation reaction of aniline with formaldehyde in the presence of an acid catalyst, i.e., the (pre) condensation reaction liquid stream of aniline with formaldehyde is subjected to partial reflux; specifically, the partially refluxed pre-condensation reaction liquid of aniline with formaldehyde, the condensation reaction liquid of aniline with formaldehyde, and aniline or aniline acid salt are mixed, and then the mixture is introduced into the reactor as an aniline stream together with a formaldehyde stream from the respective flow channels to perform the (pre) condensation reaction, i.e., the aniline stream can be a pure aniline stream, an aniline stream containing aniline acid salt, a pre-condensation reaction liquid stream of aniline with formaldehyde, a condensation reaction liquid stream of aniline with formaldehyde, or any combination thereof.

[0068] Currently, DAM in the field is prepared by continuous, semi-continuous or discontinuous reaction process of aniline with formaldehyde, and the preparation method is generally known and described in many published documents, for example, the methods disclosed in patents US20090240077A1 and WO1999040059A1 can be used. In a conventional DAM preparation process, aniline is reacted with an acid catalyst to generate aniline acid salt, and then formaldehyde is added to generate DAM acid salt, and then the DAM product is obtained through neutralization, water washing, separation, refining and other post-processing processes.

[0069] In the DAM preparation method provided by the present application, the relevant conditions of the reactor feed stream in the reaction step involving aniline and formaldehyde feed are limited. For the corresponding process operation and process conditions in other steps of the preparation method of the present application, and the devices used, the corresponding conventional selection in the art can be used, and there is no special limitation, and the skilled person can optimize according to the actual needs based on the known processes in the prior art.

[0070] For example, in some embodiments, the preparation method of the present application at least includes one of the following reaction steps:

[0071] a step of generating aniline acid salt by reacting aniline with an acid catalyst;

[0072] a step of generating a pre-condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines (DAM) by pre-condensation reaction of aniline acid salt with formaldehyde;

[0073] a step of generating a condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines (DAM) by condensation reaction of the pre-condensation reaction liquid;

[0074] a step of generating a mixture containing diamino diphenyl methane series diamines and polyamines (DAM) by transposition rearrangement reaction of the condensation reaction liquid;

[0075] a step of obtaining diamino diphenyl methane series diamines and polyamines (DAM) crude product by neutralization and separation of the mixture;

[0076] and, the step of refining the crude diamino diphenyl methane series diamines and polyamines (DAM) to obtain the DAM product.

[0077] In particular, in some embodiments, the following listed steps and conditions of the present application can be employed, for example.

[0078] A method for preparing diamino diphenyl methane series diamines and polyamines (DAM), comprising the steps of:

[0079] 1) mixing aniline and acid catalyst to perform a salt formation reaction to obtain an aniline stream containing aniline acid salt;

[0080] 2) feeding the aniline stream containing aniline acid salt obtained in step 1) and a formaldehyde stream into a pre-condensation reactor respectively from their respective flow channels to perform a pre-condensation reaction to obtain a pre-condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines (DAM);

[0081] 3) feeding the pre-condensation reaction liquid obtained in step 2) into a condensation reactor to perform a condensation reaction to obtain a condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines (DAM);

[0082] 4) performing a rearrangement reaction on the condensation reaction liquid obtained in step 3) to obtain a mixture containing diamino diphenyl methane series diamines and polyamines (DAM);

[0083] 5) adding a base to the mixture obtained in step 4) to perform a neutralization reaction, and after phase separation, obtaining an organic phase containing diamino diphenyl methane series diamines and polyamines (DAM), and then performing water washing and distillation to obtain the diamino diphenyl methane series diamines and polyamines product.

[0084] In some alternative embodiments, the molar ratio of aniline to acid catalyst in step 1) is 1:0.01-0.80, including but not limited to 1:0.01, 1:0.05, 1:0.10, 1:0.15, 1:0.20, 1:0.25, 1:0.30, 1:0.35, 1:0.40, 1:0.45, 1:0.50, 1:0.55, 1:0.60, 1:0.65, 1:0.70, 1:0.75, 1:0.80 or a range consisting of any two of them, preferably 1:0.05-0.40, more preferably 1:0.10-0.30, wherein the molar amount of acid catalyst is calculated based on H +

[0085] ​In some optional embodiments, the aniline mentioned in step 1) is a common commercially available product, usually containing a certain amount of moisture, and the present application does not have specific requirements for the concentration, for example, the aniline can have a concentration of 50.0wt%, 60.0wt%, 70.0wt%, 80.0wt%, 90.0wt%, 92.0wt%, 94.0wt%, 96.0wt%, 98.0wt%, 99.0wt%, 99.9wt% and the like; the preparation method of aniline is known to those skilled in the art, and in principle, aniline can be prepared by any desired method.

[0086] In some optional embodiments, the acid catalyst in step 1) is not specifically limited and can be one or more of organic acids, inorganic acids, and solid acids, and is preferably hydrochloric acid, for example, hydrochloric acid with a concentration of 30-37wt%, and specifically, the concentration of hydrochloric acid includes but is not limited to 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt% or a range consisting of any two of them.

[0087] In actual production, step 1) is usually to add aniline and hydrochloric acid into a salt mixer for pre-mixing and salt formation reaction to generate an aniline stream containing aniline hydrochloride.

[0088] In some optional embodiments, the reaction temperature for the salt formation reaction of aniline with the acid catalyst in step 1) is 20-100°C, preferably 35-95°C, and the reaction time is 0.01-300s, preferably 0.05-60s; specifically, the reaction temperature includes but is not limited to 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C or a range consisting of any two of them, and the reaction time includes but is not limited to 0.01s, 0.1s, 1s, 10s, 50s, 100s, 150s, 200s, 250s, 300s or a range consisting of any two of them.

[0089] In some optional embodiments, the molar ratio of formaldehyde introduced in step 2) to aniline in step 1) is 0.20-0.85:1, including but not limited to 0.20:1, 0.25:1, 0.30:1, 0.35:1, 0.40:1, 0.45:1, 0.50:1, 0.55:1, 0.60:1, 0.65:1, 0.70:1, 0.75:1, 0.80:1, 0.85:1 or a range consisting of any two of them, preferably 0.30-0.60:1, and more preferably 0.30-0.50:1.

[0090] In some optional embodiments, the formaldehyde stream mentioned in step 2) is a formaldehyde solution, in which the mass content of formaldehyde is 15-55%, preferably 30-50%.

[0091] Currently, the ordinary formaldehyde raw material on the market is mostly sold in the form of formaldehyde solution, which is obtained by absorbing gaseous formaldehyde. The preparation method of gaseous formaldehyde is known to those skilled in the art, and in principle, gaseous formaldehyde can be prepared by any desired method. The prepared gaseous formaldehyde is absorbed by using pure water, brine (such as a 0.01-26wt% aqueous solution of sodium chloride) as an absorbent, thereby obtaining a formaldehyde solution, which has a formaldehyde content of 15-55wt%, including but not limited to 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, or a range consisting of any two of them, preferably 30-50wt%.

[0092] In some optional embodiments, the reaction temperature of the pre-condensation reaction of step 2) is 20-180°C, preferably 35-150°C, more preferably 60-95°C, and the reaction time is 0.01-300s, preferably 0.05-60s. Specifically, the reaction temperature includes but is not limited to 20°C, 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, or a range consisting of any two of them, and the reaction time includes but is not limited to 0.01s, 0.1s, 1s, 10s, 50s, 100s, 150s, 200s, 250s, 300s, or a range consisting of any two of them.

[0093] In some optional embodiments, the reaction temperature of the condensation reaction of step 3) is 20-180°C, preferably 35-150°C, more preferably 60-95°C, and the reaction time is 0.01-300min, preferably 15-240min. Specifically, the reaction temperature includes but is not limited to 20°C, 40°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, or a range consisting of any two of them, and the reaction time includes but is not limited to 0.01min, 0.1min, 1min, 10min, 50min, 100min, 150min, 200min, 250min, 300min, or a range consisting of any two of them.

[0094] In some optional embodiments, the reaction temperature of the transposition reaction of step 4) is 35-180°C, preferably 60-150°C, and the reaction time is 1-10h, preferably 2-5h. Specifically, the reaction temperature includes but is not limited to 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, or a range consisting of any two of them, and the reaction time includes but is not limited to 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, or a range consisting of any two of them.

[0095] In some optional embodiments, the base used in step 5) for neutralization is not particularly limited and can be one or more of alkali metal hydroxides, alkaline earth metal hydroxides, preferably sodium hydroxide and / or potassium hydroxide.

[0096] In actual production, the base is usually prepared as an aqueous solution before being added to the mixture for neutralization, such as an aqueous sodium hydroxide solution. The mass content of the base in the aqueous solution can be 20-55%, including but not limited to 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or a range between any two of them, and is preferably 32-50%.

[0097] In some optional embodiments, the amount of base used in step 5) for neutralization is 1.0-3.0 times the amount of acid catalyst used in step 2), in terms of moles of OH - and H + , respectively, including but not limited to 1.0:1, 1.2:1, 1.5:1, 1.8:1, 2.0:1, 2.2:1, 2.5:1, 2.8:1, 3.0:1, or a range between any two of them, and is preferably 1.01-1.30:1.

[0098] In some optional embodiments, the reaction temperature for the neutralization in step 5) is 60-150°C, and the reaction time is 0.5-90 min. Specifically, the reaction temperature includes but is not limited to 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, or a range between any two of them, and the reaction time includes but is not limited to 0.5 min, 5 min, 10 min, 30 min, 50 min, 70 min, 90 min, or a range between any two of them.

[0099] After the mixture is neutralized with the base in step 4), the mixture also includes the conventional post-treatment processes such as separation of the organic phase, water washing, and distillation. In actual production, the organic phase containing the diphenylmethane series diamines and polyamines (DAM) obtained by separation can be refined into a DAM product by distilling off the aniline. The aniline removal treatment of the organic phase can be performed by vacuum distillation (while also removing water) to obtain a refined DAM product. The vacuum distillation can be performed by using a rotary evaporator, a distillation column, or the like to separate the unreacted aniline. The process conditions for vacuum distillation can also be a conventional choice in the art, which will not be described here.

[0100] In order to enable a more detailed understanding of the technical features and content of the present application, the content of the present application is further explained below in combination with specific examples. Although the preferred embodiments of the present application are described in the examples, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein.

[0101] Where no specific experimental steps or conditions are specified in the examples, the operations or conditions of the corresponding conventional experimental steps in the technical field can be followed. Where no manufacturer of the reagents or instruments is specified, they are all conventional products that can be obtained commercially. Among them:

[0102] In the examples and comparative examples of the present application, the main raw materials used are as follows:

[0103] Formaldehyde: formaldehyde aqueous solution with a concentration of 37wt%, obtained by catalytic oxidation of methanol with air in the industrial park of Wanhua Chemical (Fujian) Isocyanate Co., Ltd.

[0104] Aniline: purity 94wt%, obtained by catalytic reduction of nitrobenzene with hydrogen in the industrial park of Wanhua Chemical (Fujian) Isocyanate Co., Ltd.

[0105] The main analysis methods used in the examples and comparative examples of the present application are as follows:

[0106] Isomer and N-methyl impurity content in DAM: analyzed by Agilent 1260 Infinity II high performance liquid chromatograph; instrument analysis operating parameters are as follows: the substance is separated by using a waters SymmetryShield RP185um*4.6*250mm chromatographic column, and a DAD detector is used to detect the signal at a wavelength of 250-280nm; wherein the flow rate of the mobile phase is controlled at 1ml / min, the injection volume is 5-10uL, the column temperature is 35-45℃, and the mobile phase is acetonitrile and water eluted by gradient according to the volume ratio, and the ratio range is 20%-80% acetonitrile.

[0107] Flow channel diameter D: directly measured by measuring tools such as vernier caliper, tape measure, etc. or calculated according to the cross-sectional area and wet perimeter length to obtain the equivalent diameter, wherein the equivalent diameter refers to the diameter of a circular pipe with the same hydraulic radius, i.e. 4 times the cross-sectional area divided by the wet perimeter length.

[0108] Flow rate V of the flow in the flow channel: the flow rate is calculated by monitoring the flow by flow meter instrument and the size of the flow channel.

[0109] Viscosity μ of the flow: tested by using a BROOKFIELD DV2T viscometer, wherein the rotation speed is controlled at 20-200rpm and the temperature is controlled at 20-95℃.

[0110] Differential pressure ΔP: The differential pressure is calculated by subtracting the back pressure from the pressure in the flow channel, which is read by an online pressure detector.

[0111] Flow resistance: The ratio of the maximum cross-sectional area of the blockage perpendicular to the flow channel to the flow area of the flow channel.

[0112] Operation cycle: The continuous operation time interval of the equipment.

[0113] The preparation method provided by the present application is described in detail below through specific examples.

[0114] Example 1

[0115] The preparation of diamines and polyamines (DAM) of the diphenylmethane series is as follows:

[0116] 1) Aniline with a purity of 94wt% and hydrochloric acid with a concentration of 33wt% are added to a static mixer to perform a salting reaction to generate an aniline stream containing aniline hydrochloride, the salting reaction has a residence time of 60s and a reaction temperature of 35℃; wherein the molar ratio of the catalyst hydrochloric acid (calculated as H + ) to aniline (calculated as -NH2) is 0.40;

[0117] 2) The aniline stream containing aniline hydrochloride is passed through an aniline flow channel and the formaldehyde stream with a concentration of 37wt% is passed through two formaldehyde flow channels into a pre-condensation reactor to perform a pre-condensation reaction, the reaction has a residence time of 60s and a reaction temperature of 60℃; wherein the molar ratio of formaldehyde to aniline (calculated as -NH2) in step 1) is 0.56, and a pre-condensation reaction liquid containing DAM is obtained;

[0118] Wherein, the values of the related parameters D, V, μ, ΔP of the aniline stream are 150mm, 0.5m / s, 1.8cP, 1kPa respectively, and the correlation characteristic parameter ε is 1.1*10 -5 ; the values of the related parameters D, V, μ, ΔP of the formaldehyde stream are 25mm, 7.2m / s, 0.4cP, 1kPa respectively, and the correlation characteristic parameter ε is 3.3*10 -5 ;

[0119] 3) The pre-condensation reaction liquid is passed into a condensation reaction kettle to perform a condensation reaction, the reaction has a reaction temperature of 60℃ and a reaction time of 240min, and a condensation reaction liquid containing DAM is obtained;

[0120] 4) The condensation reaction liquid is passed into a rearrangement kettle to perform a rearrangement reaction, the reaction has a reaction temperature of 150℃ and a reaction time of 5h, and a mixture containing DAM is obtained;

[0121] 5) adding 50wt% sodium hydroxide aqueous solution to the mixture, the neutralization reaction is carried out at 115℃ for 30min under stirring; wherein the molar ratio of sodium hydroxide aqueous solution (calculated by OH - ) to hydrochloric acid (calculated by H + ) in step 1) is 1.05; then the product liquid obtained by neutralization is subjected to two-phase separation to obtain a salt-containing aqueous phase and an organic phase containing DAM, and the organic phase is subjected to water washing and distillation treatment to obtain a refined DAM product.

[0122] The isomer and N-methyl impurity contents of the refined DAM are analyzed by using an Agilent 1260 Infinity II high-performance liquid chromatograph, and the flow resistance of the aniline stream and the formaldehyde stream of the pre-condensation reactor is calculated, and the results are shown in Table 1.

[0123] Example 2

[0124] The preparation of diamines and polyamines (DAM) in the series of diphenylmethane is as follows:

[0125] 1) adding 94wt% pure aniline and 33wt% concentrated hydrochloric acid into a static mixer to generate an aniline stream containing aniline hydrochloride by salt formation reaction, the residence time of the salt formation reaction is 0.05s, and the reaction temperature is 95℃; wherein the molar ratio of the catalyst hydrochloric acid (calculated by H + ) to aniline (calculated by -NH2) is 0.40;

[0126] 2) passing the aniline stream containing aniline hydrochloride through an aniline flow channel and a 37wt% formaldehyde stream through eight formaldehyde flow channels into a pre-condensation reactor to perform a pre-condensation reaction, the residence time of the reaction is 0.05s, and the reaction temperature is 95℃; wherein the molar ratio of formaldehyde to aniline (calculated by -NH2) in step 1) is 0.56, and a pre-condensation reaction liquid containing DAM is obtained;

[0127] Wherein, the values of the related parameters D, V, μ, ΔP of the aniline stream are 200mm, 0.7m / s, 30cP, 1kPa respectively, and the correlation characteristic parameter ε is 1.2*10 -4 ; the values of the related parameters D, V, μ, ΔP of the formaldehyde stream are 6mm, 15.7m / s, 0.4cP, 1kPa respectively, and the correlation characteristic parameter ε is 7.2*10 -4 ;

[0128] 3) passing the pre-condensation reaction liquid into a condensation reaction kettle to perform a condensation reaction, the reaction temperature is 95℃, and the reaction time is 15min, and a condensation reaction liquid containing DAM is obtained;

[0129] 4) The condensation reaction liquid is introduced into a shift kettle to perform a shift rearrangement reaction, the reaction temperature is 150°C, and the reaction time is 5h to obtain a mixture containing DAM;

[0130] 5) The mixture is added with a 50wt% sodium hydroxide aqueous solution, the reaction temperature is 115°C, and the neutralization reaction is performed for 30min under stirring; wherein the molar ratio of the sodium hydroxide aqueous solution (calculated as OH - ) to the hydrochloric acid (calculated as H + ) in step 1) is 1.05; then the neutralized product liquid is subjected to two-phase separation to obtain a salt-containing aqueous phase and an organic phase containing DAM, and the organic phase is subjected to water washing and distillation treatment to obtain a refined DAM product.

[0131] The isomer and N-methyl impurity contents of the refined DAM are analyzed by using an Agilent 1260Infinity II high-performance liquid chromatograph, and the flow resistance of the aniline stream and the formaldehyde flow channel of the pre-condensation reactor is calculated, and the results are shown in Table 1.

[0132] Example 3

[0133] The preparation of diamines and polyamines (DAM) in the series of diphenylmethane is as follows:

[0134] 1) Aniline with a purity of 94wt% and hydrochloric acid with a concentration of 33wt% are added to a static mixer to perform a salt formation reaction to generate aniline hydrochloride-containing stream, the salt formation reaction residence time is 1.2s, and the reaction temperature is 45°C; wherein the molar ratio of the catalyst hydrochloric acid (calculated as H + ) to aniline (calculated as -NH2) is 0.40;

[0135] 2) The aniline hydrochloride-containing stream is mixed with a reflux pre-condensation reaction liquid stream at a mass ratio of 1:1 to form an aniline stream, which is introduced into a pre-condensation reactor through sixteen aniline flow channels, and a formaldehyde stream with a concentration of 37wt% is introduced into the pre-condensation reactor through sixteen formaldehyde flow channels to perform a pre-condensation reaction, the reaction residence time is 1.5s, and the reaction temperature is 65°C; wherein the molar ratio of formaldehyde to aniline (calculated as -NH2) in step 1) is 0.56, and a pre-condensation reaction liquid containing DAM is obtained;

[0136] Wherein, the values of the related parameters D, V, μ, ΔP of the aniline stream are 30mm, 1.7m / s, 200cP, and 10kPa respectively, the correlation characteristic parameter ε is 0.03, the values of the related parameters D, V, μ, ΔP of the formaldehyde stream are 3mm, 31.3m / s, 200cP, and 1kPa respectively, and the correlation characteristic parameter ε is 4.7;

[0137] 3) The pre-condensation reaction liquid is introduced into the condensation reactor for condensation reaction, the reaction temperature is 95℃, and the reaction time is 60 min, to obtain a condensation reaction liquid containing DAM;

[0138] 4) The condensation reaction liquid is introduced into the rearrangement reactor for rearrangement reaction, the reaction temperature is 120℃, and the reaction time is 2 h, to obtain a mixture containing DAM;

[0139] 5) The mixture is added with a 50wt% sodium hydroxide aqueous solution, the reaction temperature is 115℃, and the neutralization reaction is performed for 30 min under stirring; wherein the molar ratio of the sodium hydroxide aqueous solution (calculated as OH - ) to the hydrochloric acid (calculated as H + ) in step 1) is 1.05; then the neutralized product liquid is subjected to two-phase separation to obtain a salt-containing aqueous phase and an organic phase containing DAM, and the organic phase is subjected to water washing and distillation treatment to obtain a refined DAM product.

[0140] The isomer and N-methyl impurity contents of the refined DAM are analyzed by using an Agilent 1260 Infinity II high-performance liquid chromatograph, and the flow resistance of the aniline stream and the formaldehyde flow channel of the pre-condensation reactor is calculated, and the results are shown in Table 1.

[0141] Example 4

[0142] The preparation of diamines and polyamines (DAM) in the series of diphenylmethane is as follows:

[0143] Compared with Example 3, the values of the related parameters D, V, μ, ΔP of the aniline stream in step 2) are 10 mm, 15.2 m / s, 200 cP, and 1 kPa, respectively, the correlation characteristic parameter ε is 0.4, the values of the related parameters D, V, μ, ΔP of the formaldehyde stream are 3 mm, 31.3 m / s, 80 cP, and 1 kPa, respectively, and the correlation characteristic parameter ε is 1.6. Other operations and conditions remain unchanged, and the results are shown in Table 1.

[0144] Comparative Example 1

[0145] Referring to the method of Example 3, the difference is that the values of the related parameters D, V, μ, ΔP of the aniline stream in step 2) are 10 mm, 15.2 m / s, 2000 cP, and 1 kPa, respectively, the correlation characteristic parameter ε is 5.6, the values of the related parameters D, V, μ, ΔP of the formaldehyde stream are 3 mm, 31.3 m / s, 300 cP, and 1 kPa, respectively, and the correlation characteristic parameter ε is 7.6. Other operations and conditions remain unchanged, and the results are shown in Table 1.

[0146] Comparative Example 2

[0147] The method of Example 3 was referred to, except that in Step 2), the values of the relevant parameters D, V, μ, ΔP of the formaldehyde stream were 3 mm, 31.3 m / s, 250 cP, 1 kPa, respectively, and the correlation characteristic parameter ε was 6.1. Other operations and conditions were unchanged, and the results are shown in Table 1.

[0148] Comparative Example 3

[0149] The method of Example 3 was referred to, except that in Step 2), the values of the relevant parameters D, V, μ, ΔP of the aniline stream were 8 mm, 23.8 m / s, 1500 cP, 1 kPa, respectively, and the correlation characteristic parameter ε was 5.3. Other operations and conditions were unchanged, and the results are shown in Table 1.

[0150] Comparative Example 4

[0151] Based on Example 3 above, the system after 300 days of continuous stable operation was used, and only the values of the relevant parameters μ, ΔP of the aniline stream in Step 2) were adjusted to 10000 cP, 1 kPa, respectively, and the correlation characteristic parameter ε was adjusted from 0.03 to 9.3. Other operations and conditions were unchanged, and the results are shown in Table 1.

[0152] Table 1: Effect data of examples and comparative examples

[0153]

[0154] According to the data in Table 1, the running period of Examples 1-4 is > 300 days, indicating that the equipment has not been blocked within a continuous operation time interval of 300 days (in actual production, for safety, stability and other factors, it will not be operated indefinitely, and needs to be checked and maintained regularly, and the time interval generally will not exceed 300 days), and does not mean that it will be blocked after 300 days. In theory, as long as the correlation characteristic parameter ε of the aniline stream and the formaldehyde stream entering the reactor is maintained to be ≤ 5, the flow resistance rate can be kept < 0.0001%, and the DAM production can be operated stably for a long time; the flow resistance rate of Examples 1-4 is < 0.0001%, indicating that it tends to be 0 or equal to 0.

[0155] In the DAM production, if the mixing effect of formaldehyde and aniline in the condensation / pre-condensation reaction process is poor and the dispersion effect of formaldehyde is poor, a large amount of high polymer is quickly generated, and the reactor is frequently blocked. According to the preparation method of the present application, once the characteristic parameter ε of the aniline stream and the formaldehyde stream is greater than 5, the flow resistance rate will quickly increase from 0 to 100%, and then the pipeline will be blocked. This point can also be proved by the data of the examples and the comparative examples of the present application. As can be seen from the data in Table 1, the flow resistance rate of the formaldehyde / aniline flow channel of Examples 1-4 remained <0.0001% during the continuous operation of 300 days, while the flow resistance rate of Comparative Examples 1-3 reached 100% and the pipelines were blocked within one day of operation. Comparative Example 4 is an adjustment based on the operation of Example 3 for 300 days, and the pipeline was also blocked within one day of operation after the adjustment.

Claims

1. A process for the preparation of diamines and polyamines of the diphenylmethane series, said process comprising the step of reacting aniline with formaldehyde in the presence of an acid catalyst, wherein, The aniline stream and the formaldehyde stream are respectively introduced into the reactor from the respective flow channels; The aniline stream and the formaldehyde stream respectively satisfy a characteristic parameter ε≤5, preferably a characteristic parameter ε≤3, more preferably a characteristic parameter ε≤2, and further preferably a characteristic parameter ε≤1, wherein the characteristic parameter ε is calculated according to formula (1): In formula (1), D is the diameter of the flow channel, mm; V is the flow rate of the stream in the flow channel, m / s; μ is the viscosity of the stream, cP; and ΔP is the pressure difference between the flow channel pressure and the back pressure of the flow channel, kPa.

2. The production method according to claim 1, characterized by, The reaction of the aniline with the formaldehyde in the presence of the acid catalyst includes a condensation reaction or a pre-condensation reaction.

3. The production method according to claim 1 or 2, characterized by, The aniline stream is an amine group-containing stream; and / or The aniline stream and the formaldehyde stream each have at least one flow channel, and can also have two or more flow channels.

4. The production method according to any one of claims 1 to 3, characterized by, The reaction of the aniline with the formaldehyde in the presence of the acid catalyst is a pre-condensation reaction, and the steps of the pre-condensation reaction further include: a step of reacting the aniline with the acid catalyst to generate an aniline acid salt; and / or a step of performing a condensation reaction on the pre-condensation reaction liquid to generate a condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines; and / or a step of performing a rearrangement reaction on the condensation reaction liquid to generate a mixture containing diamino diphenyl methane series diamines and polyamines; and / or a step of neutralizing, separating and obtaining diamino diphenyl methane series diamines and polyamines crude products from the mixture containing diamino diphenyl methane series diamines and polyamines; and / or a step of refining the diamino diphenyl methane series diamines and polyamines crude products to obtain DAM products.

5. The method of any one of claims 1-4, wherein the method further comprises, The method comprises the following steps: 1) mixing the aniline and the acid catalyst to perform a salt formation reaction, to generate an aniline stream containing an aniline acid salt; 2) introducing the aniline stream containing the aniline acid salt obtained in step 1) and a formaldehyde stream into a pre-condensation reactor from respective flow channels to perform a pre-condensation reaction, to obtain a pre-condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines; 3) introducing the pre-condensation reaction liquid obtained in step 2) into a condensation reactor to perform a condensation reaction, to obtain a condensation reaction liquid containing diamino diphenyl methane series diamines and polyamines; 4) performing a rearrangement reaction on the condensation reaction liquid obtained in step 3) to obtain a mixture containing diamino diphenyl methane series diamines and polyamines; 5) adding a base to the mixture obtained in step 4) to perform neutralization, to obtain an organic phase containing diamino diphenyl methane series diamines and polyamines, and then performing water washing and distillation to obtain diamino diphenyl methane series diamines and polyamines products.

6. The production method according to claim 5, wherein The molar ratio of the aniline to the acid catalyst in step 1) is 1 : 0.01 to 0.80, preferably 1 : 0.05 to 0.40, more preferably 1 : 0.10 to 0.30, wherein the acid catalyst is based on the molar amount of H + ; and / or The acid catalyst in step 1) is selected from one or more of an organic acid, an inorganic acid and a solid acid, and is preferably hydrochloric acid, and more preferably hydrochloric acid with a concentration of 30-37 wt%; and / or The salt formation reaction in step 1) is performed at a reaction temperature of 20-100°C, and preferably 35-95°C, and a reaction time of 0.01-300 s, and preferably 0.05-60 s.

7. The preparation method according to claim 5, characterized in that, The molar ratio of the formaldehyde to the aniline in step 1) is 0.20-0.85:1, preferably 0.30-0.60:1, and more preferably 0.30-0.50:1; and / or Step 2) the reaction temperature of the precondensation reaction is 20-180°C, preferably 35-150°C, more preferably 60-95°C, and the reaction time is 0.01-300s, preferably 0.05-60s.

8. The preparation method according to claim 5, characterized in that, Step 3) the reaction temperature of the condensation reaction is 20-180°C, preferably 35-150°C, more preferably 60-95°C, and the reaction time is 0.01-300min, preferably 15-240min.

9. The preparation method according to claim 5, characterized in that, Step 4) the reaction temperature of the transposition rearrangement reaction is 35-180°C, preferably 60-150°C, and the reaction time is 1-10h, preferably 2-5h.

10. The method of claim 5, wherein, Step 5) the base is selected from one or more of alkali metal hydroxides, alkaline earth metal hydroxides, preferably one or more of sodium hydroxide, potassium hydroxide; and / or The amount of alkali used in step 5) and the amount of acid catalyst used in step 2) are respectively expressed in terms of OH... - and H + The molar ratio of the two is calculated to be 1.0–3.0:1, preferably 1.01–1.30:1; and / or Step 5) the reaction temperature of the neutralization is 60-150°C, and the reaction time is 0.5-90min.

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