Production method of HMDA

Abstract

The invention discloses a production method of HMDA (4, 4 '-MDA), which comprises a process of pretreating a catalyst before a catalytic hydrogenation reaction of 4, 4'-MDA, the pretreatment method of the catalyst comprises the following steps: mixing the catalyst, a solvent and a heavy component-reaction regulator, treating for a period of time in a high-temperature hydrogen atmosphere, filtering out the catalyst after the treatment is finished, and carrying out a subsequent catalytic hydrogenation reaction; the heavy component, namely the trans regulator, is cis-1, 4-di (aminomethyl) cyclohexane; preferably, the addition amount of the heavy component, namely the anti-reaction regulator, is 0.1-15 wt% of the mass of the catalyst. The yield of the H12MDA exceeds 95%, the trans-trans isomer content is 13-15%, no heavy components are generated, the unit consumption of the raw materials is greatly reduced, and the catalyst is not inactivated after being used for 60 batches.

Description

Technical Field

[0001] The present invention relates to an improved production method, in particular to a production method of HMDA. Background Art

[0002] 4,4'-H 12 MDA is produced by hydrogenation of 4,4'-MDA. It exists in three isomers: cis-cis, cis-trans and trans-trans. The reaction flow diagram is as follows:

[0003]

[0004] H 12 The melting point of MDA products is related to the composition of the three isomers, especially the trans-trans isomer. When the content of the trans-trans isomer is lower, its melting point is lower and the fluidity of the product is better. 12 MDA products have different application areas. When the content of trans-isomer is above 50%, H 12 MDA is mainly used in the production of polyamide; when the trans-isomer content is below 24%, in addition to being used as an amine epoxy curing agent, H 12 MDA is mainly used to prepare a new generation of anti-aging polyurethane dicyclohexylmethane diisocyanate (H 12 MDI), which is also the current H 12 The main application area of ​​MDA products. The lower the content of trans-isomer, the lower the 12 During the photochemical production of MDA, H 12 The more difficult it is for MDA to crystallize, the less likely it is to precipitate, thus avoiding blockage of the reaction system. However, since the trans-isomer is a thermodynamically controlled product, its structure is the most stable among the three isomers. If the catalyst is not improved or the process is not optimized, a high content of the trans-isomer H will be formed first. 12 MDA products.

[0005] The prior art is directed to the preparation of H with low anti-anti content. 12 MDA proposes different solutions, such as:

[0006] CN103265438A discloses a method for preparing diaminodicyclohexylmethane (HDI) by hydrogenating diaminodiphenylmethane (MDA). 12 The MDA) method is to switch 2,4'-MDA and 4,4'-MDA for joint production, thereby extending the life of the catalyst. The trans-trans isomer obtained by this method is about 16-24%.

[0007] CN106631826B discloses a method for preparing diaminodicyclohexylmethane (HDI) by hydrogenating diaminodiphenylmethane (MDA). 12The MDA method utilizes the acidity of phenolic compounds to reduce the generation of tar, improve the activity of the catalyst, and increase the production efficiency during the hydrogenation process. The reaction rate is about 17-24%.

[0008] US5196594A discloses a continuous hydrogenation reduction process for MDA, using supported ruthenium as a catalyst. 12 The yield of MDA can reach 93.7%, but at high yields, the reaction rate is higher, greater than 20%.

[0009] CN109851508B discloses a method for synthesizing HMDA with low trans-isomer content and low tar content, which comprises a two-step synthesis, a partial hydrogenation reaction under the action of catalyst I to produce diaminomonocyclohexylmonophenylmethane (i.e., one benzene ring in MDA is hydrogenated, H6MDA); the obtained product is fully hydrogenated under the action of catalyst II to produce H 12 MDA, wherein the tar yield is less than 2%, the other by-product yields are less than 1%, and the trans-trans isomer content is 10-14%.

[0010] The above prior art still has the following defects that need to be solved:

[0011] Currently, 4,4'-diaminodiphenylmethane (MDA) is used as raw material to produce low-trans 4,4'-diaminodicyclohexylmethane (H 12 In the MDA method, more heavy components will be produced, and most of them cannot control the content of the anti-antibody at a low level. At the same time, the catalyst life is short, and it is impossible to maintain good reaction results in multiple batches. Summary of the invention

[0012] In order to solve the above technical problems, the present invention provides a method for producing HMDA. 12 The MDA yield exceeds 95%, the trans-trans isomer content is 13-15%, and no heavy components are generated, which greatly reduces the unit consumption of raw materials. The catalyst can be used for 60 batches without deactivation.

[0013] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0014] A method for producing HMDA, comprising a process of pretreating a catalyst before a catalytic hydrogenation reaction of 4,4'-MDA;

[0015] The catalyst pretreatment method is:

[0016] The catalyst, solvent and heavy component-anti-anti regulator are mixed and treated for a period of time in a high temperature hydrogen atmosphere. After the treatment, the catalyst is filtered out and a subsequent catalytic hydrogenation reaction is performed; the heavy component-anti-anti regulator is cis-1,4-di(aminomethyl)cyclohexane;

[0017] Preferably, the added amount of the heavy component-reverse regulator is 0.1-15wt% of the catalyst mass.

[0018] The present invention uses cis-1,4-di(aminomethyl)cyclohexane as a regulator, and the catalyst is more likely to generate a cis structure during the MDA hydrogenation process after pretreatment, thereby reducing the reverse selectivity, and the method is beneficial to promoting H 12 The desorption process of MDA from the catalyst interior inhibits the formation of heavy components.

[0019] In some preferred examples, the catalyst is a supported catalyst comprising an active metal and a carrier, preferably a supported catalyst Ru / SiO2;

[0020] Preferably, the active metal includes any one or more of Pd, Pt, Ir, Co, Ru, and Rh;

[0021] Preferably, the carrier includes any one or more of activated carbon, silicon oxide, aluminum oxide, zirconium oxide, barium sulfate, and calcium carbonate;

[0022] Preferably, the content of active metal in the catalyst is 0.1-10 wt%, preferably 4-5 wt%.

[0023] In some preferred examples, during the catalyst pretreatment process, the solvent is selected from any one or more of methanol, ethanol, isopropanol, n-butanol, 2-butanol, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, n-hexane, cyclohexane, and methylcyclohexane;

[0024] Preferably, the amount of solvent added is 50-80 times the mass of the catalyst.

[0025] In some preferred examples, during the catalyst pretreatment process, the treatment conditions of the high-temperature hydrogen atmosphere are: treatment temperature is 80-200° C., hydrogen pressure is 1-10 MPa, and treatment time is 0.5-12 h.

[0026] In some preferred examples, the catalytic hydrogenation reaction includes hydrogenating 4,4'-MDA under the action of a pretreated catalyst; the reaction temperature is 100-200°C, the hydrogen pressure is 3-12MPa, and the reaction time is 0.5-8h.

[0027] In some preferred examples, the catalytic hydrogenation reaction is carried out in a solvent, and the solvent is selected from any one or more of methanol, ethanol, isopropanol, n-butanol, 2-butanol, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, n-hexane, cyclohexane, and methylcyclohexane, and the amount of the solvent is such that the mass concentration of 4,4'-MDA is 30-60wt%.

[0028] In some preferred examples, in the catalytic hydrogenation reaction, the amount of catalyst used is 0.1-2 wt % of the mass of 4,4'-MDA.

[0029] The beneficial technical effects of the present invention are as follows:

[0030] (1) Pre-treating the catalyst with a heavy component-reverse regulator to change the catalyst pore structure and promote MDA to more easily generate a cis structure during hydrogenation, thereby reducing the reverse content;

[0031] (2) Pre-treating the catalyst with a heavy component-reverse regulator has been shown to accelerate H 12 The desorption process of MDA from the catalyst accelerates the reaction and inhibits the formation of heavy components.

[0032] (3) Since no heavy components are generated, the organic matter adsorbed on the catalyst can be easily removed by solvent, which prolongs the life of the catalyst. It can be used for 60 batches without deactivation. In addition, it was found during the experiment that the filtration efficiency of the catalyst after the hydrogenation reaction was high. DETAILED DESCRIPTION

[0033] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0034] Unless otherwise specified, the raw materials used in the following examples or comparative examples are all commercially available industrial-grade conventional raw materials. The main raw materials and testing instrument information are as follows:

[0035] 4,4'-MDA was obtained from Wanhua Chemical with a purity greater than 99%.

[0036] n-Butanol was purchased from Beijing Inokai Technology Co., Ltd. of analytical grade.

[0037] Ru / SiO2 catalyst was purchased from Johnson Matthey.

[0038] Cis-1,4-bis(aminomethyl)cyclohexane was purchased from Beijing Inokai Technology Co., Ltd.

[0039] The gas chromatograph was Agilent 7890B, DB-5 capillary column, FID detector temperature was 300℃, the initial column temperature was 50℃, increased to 300℃ at 10℃ / min, and stayed for 20min. 12 MDA stands for trans-trans isomer.

[0040] [Example 1]

[0041] (1) Catalyst pretreatment: Add 1.0 g of Ru / SiO2 catalyst (Ru 1 wt%), 80 g of n-butanol solvent, and 0.005 g of cis-1,4-di(aminomethyl)cyclohexane into a 1L reactor, replace it with 1 MPa(G) of N2 three times, then replace it with 1 MPa(G) of H2 three times, and then fill the pressure with H2 to 1 MPa. Raise the temperature to 100°C, control the target pressure to 10 MPa, cool down and filter after 5 hours to remove the solvent.

[0042] (2) Hydrogenation reaction: 250g of raw material MDA was dissolved in 500g of n-butanol solvent and added to the reactor containing the pre-treated catalyst. After displacement with 1MPa(G) of N2 three times, it was then replaced with 1MPa(G) of H2 three times. Then the H2 pressure was supplemented to 1MPa. The temperature was raised to 180°C, the target pressure was controlled to 4MPa, and after reacting for 4h, the temperature was lowered and filtered, and samples were taken for analysis. The results are shown in Table 1.

[0043] Table 1. Analysis results of the reaction solution in Example 1

[0044] <![CDATA[H 12 MDA / %]]> <![CDATA[t,t-H 12 MDA / %]]> other / % Conversion rate / % Run1 95.88 14.12 4.12 100 Run20 95.27 14.31 4.73 100 Run60 94.59 14.82 5.41 100

[0045] Note: Others mainly include intermediate hydrogenation component H6MDA and light components, and no heavy components were detected

[0046] [Example 2]

[0047] (1) Catalyst pretreatment: Add 1.5 g of Ru / SiO2 catalyst (Ru 5 wt%), 90 g of n-butanol solvent, and 0.03 g of cis-1,4-di(aminomethyl)cyclohexane into a 1L reactor, replace it with 1 MPa(G) of N2 three times, then replace it with 1 MPa(G) of H2 three times, and then fill the pressure with H2 to 1 MPa. Raise the temperature to 180°C, control the target pressure to 8 MPa, cool down and filter after 4 hours to remove the solvent.

[0048] (2) Hydrogenation reaction: 100g of raw material MDA was dissolved in 100g of n-butanol solvent and added to the reactor containing the pre-treated catalyst. After displacement with 1MPa(G) of N2 three times, it was then replaced with 1MPa(G) of H2 three times. Then the H2 pressure was supplemented to 1MPa. The temperature was raised to 120°C, the target pressure was controlled to 10MPa, and after reacting for 3h, the temperature was lowered and filtered, and samples were taken for analysis. The results are shown in Table 2 below.

[0049] Table 2. Analysis results of the reaction solution in Example 2

[0050]

[0051]

[0052] Note: Others mainly include intermediate hydrogenation component H6MDA and light components, and no heavy components were detected

[0053] [Example 3]

[0054] (1) Catalyst pretreatment: 1.5 g of Ru / SiO2 catalyst (Ru 5 wt%), 90 g of n-butanol solvent, and 0.075 g of cis-1,4-di(aminomethyl)cyclohexane were added to a 1L reactor, and the atmosphere was replaced three times with 1 MPa(G) of N2, and then replaced three times with 1 MPa(G) of H2, and then the pressure was supplemented with H2 to 1 MPa. The temperature was raised to 180°C, and the target pressure was controlled to 8 MPa. After 4 hours, the temperature was lowered and filtered to remove the solvent.

[0055] (2) Hydrogenation reaction: 100 g of raw material MDA was dissolved in 100 g of n-butanol solvent and added to the reactor containing the pre-treated catalyst. After displacement with 1 MPa (G) of N2 three times, it was then replaced with 1 MPa (G) of H2 three times. Then the H2 pressure was supplemented to 1 MPa. The temperature was raised to 150°C, the target pressure was controlled to 3 MPa, and after reacting for 2 hours, the temperature was lowered and filtered, and samples were taken for analysis. The results are shown in Table 3 below.

[0056] Table 3. Analysis results of the reaction solution in Example 3

[0057] <![CDATA[H 12 MDA / %]]> <![CDATA[t,t-H 12 MDA / %]]> other / % Conversion rate / % Run1 96.72 12.85 3.28 100 Run20 96.38 13.11 3.62 100 Run60 96.08 13.26 3.92 100

[0058] Note: Others mainly include intermediate hydrogenation component H6MDA and light components, and no heavy components were detected

[0059] [Example 4]

[0060] (1) Catalyst pretreatment: Add 1.5 g of Ru / SiO2 catalyst (Ru 5 wt%), 90 g of n-butanol solvent, and 0.15 g of cis-1,4-di(aminomethyl)cyclohexane into a 1L reactor, replace it with 1 MPa(G) of N2 three times, then replace it with 1 MPa(G) of H2 three times, and then fill the pressure with H2 to 1 MPa. Raise the temperature to 120°C, control the target pressure to 5 MPa, cool down and filter after 3 hours to remove the solvent.

[0061] (2) Hydrogenation reaction: 150 g of raw material MDA was dissolved in 150 g of n-butanol solvent and added to the reactor containing the pre-treated catalyst. After displacement with 1 MPa (G) of N2 three times, it was then replaced with 1 MPa (G) of H2 three times. Then the H2 pressure was supplemented to 1 MPa. The temperature was raised to 150°C, the target pressure was controlled to 8 MPa, and after reacting for 2 hours, the temperature was lowered and filtered, and samples were taken for analysis. The results are shown in Table 4 below.

[0062] Table 4. Analysis results of the reaction solution in Example 4

[0063] <![CDATA[H 12 MDA / %]]> <![CDATA[t,t-H 12 MDA / %]]> other / % Conversion rate / % Run1 96.23 12.91 3.77 100 Run20 95.81 13.18 4.19 100 Run60 95.36 13.27 4.64 100

[0064] Note: Others mainly include intermediate hydrogenation component H6MDA and light components, and no heavy components were detected

[0065] [Example 5]

[0066] (1) Catalyst pretreatment: Add 2g of Ru / SiO2 catalyst (Ru 4wt%), 100g of solvent n-butanol, and 0.24g of cis-1,4-di(aminomethyl)cyclohexane into a 1L reactor, replace it with 1MPa(G) of N2 three times, then replace it with 1MPa(G) of H2 three times, and then fill the pressure with H2 to 1MPa. Raise the temperature to 200℃, control the target pressure to 6MPa, cool down and filter after 5h to remove the solvent.

[0067] (2) Hydrogenation reaction: 200 g of raw material MDA was dissolved in 300 g of n-butanol solvent and added to the reactor containing the pre-treated catalyst. After displacement with 1 MPa (G) of N2 for three times, it was then replaced with 1 MPa (G) of H2 for three times. Then the H2 pressure was supplemented to 1 MPa. The temperature was raised to 160°C, the target pressure was controlled to 6 MPa, and after reacting for 3 hours, the temperature was lowered and filtered, and samples were taken for analysis. The results are shown in Table 5 below.

[0068] Table 5. Analysis results of the reaction solution in Example 5

[0069] <![CDATA[H 12 MDA / %]]> <![CDATA[t,t-H 12 MDA / %]]> other / % Conversion rate / % Run1 96.06 13.25 3.94 100 Run20 95.58 13.37 4.42 100 Run60 95.21 13.58 4.79 100

[0070] Note: Others mainly include intermediate hydrogenation component H6MDA and light components, and no heavy components were detected

[0071] [Comparative Example 1]

[0072] Referring to the method basically the same as Example 2, H 12 MDA, the only difference is that no cis-1,4-di(aminomethyl)cyclohexane is added during the catalyst pretreatment in step (1). After the reaction, samples were taken for analysis, and the results are shown in Table 6 below.

[0073] Table 6. Analysis results of the reaction solution in Example 6

[0074] <![CDATA[H 12 MDA / %]]> <![CDATA[t,t-H 12 MDA / %]]> Heavy component / % other / % Conversion rate / % Run1 91.52 17.89 3.17 5.31 100 Run20 88.93 18.66 4.56 6.51 100 Run60 85.05 19.25 6.24 8.71 100

[0075] Note: Others mainly include intermediate hydrogenation component H6MDA and light components

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A method for producing HMDA, characterized in that: It includes a process of pretreating the catalyst before the catalytic hydrogenation reaction of 4,4'-MDA; The catalyst pretreatment method is: The catalyst, solvent and heavy component-anti-anti regulator are mixed and treated for a period of time in a high temperature hydrogen atmosphere. After the treatment, the catalyst is filtered out and a subsequent catalytic hydrogenation reaction is performed; the heavy component-anti-anti regulator is cis-1,4-di(aminomethyl)cyclohexane; Preferably, the added amount of the heavy component-reverse regulator is 0.1-15wt% of the catalyst mass.

2. The method for producing HMDA according to claim 1, characterized in that: The catalyst is a supported catalyst comprising an active metal and a carrier, preferably a supported catalyst Ru / SiO2; Preferably, the active metal includes any one or more of Pd, Pt, Ir, Co, Ru, and Rh; Preferably, the carrier includes any one or more of activated carbon, silicon oxide, aluminum oxide, zirconium oxide, barium sulfate, and calcium carbonate; Preferably, the content of active metal in the catalyst is 0.1-10 wt%, preferably 4-5 wt%.

3. The method for producing HMDA according to claim 1, characterized in that: During the catalyst pretreatment process, the solvent is selected from any one or more of methanol, ethanol, isopropanol, n-butanol, 2-butanol, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, n-hexane, cyclohexane, and methylcyclohexane; Preferably, the amount of solvent added is 50-80 times the mass of the catalyst.

4. The method for producing HMDA according to any one of claims 1 to 3, characterized in that: During the catalyst pretreatment process, the treatment conditions of the high-temperature hydrogen atmosphere are: treatment temperature is 80-200°C, hydrogen pressure is 1-10MPa, and treatment time is 0.5-12h.

5. The method for producing HMDA according to any one of claims 1 to 4, characterized in that: The catalytic hydrogenation reaction comprises: carrying out a hydrogenation reaction of 4,4'-MDA under the action of a pretreated catalyst; the reaction temperature is 100-200°C, the hydrogen pressure is 3-12MPa, and the reaction time is 0.5-8h.

6. The method for producing HMDA according to any one of claims 1 to 5, characterized in that: The catalytic hydrogenation reaction is carried out in a solvent, and the solvent is selected from any one or more of methanol, ethanol, isopropanol, n-butanol, 2-butanol, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, n-hexane, cyclohexane, and methylcyclohexane. The amount of the solvent used is such that the mass concentration of 4,4'-MDA is 30-60wt%.

7. The method for producing HMDA according to any one of claims 1 to 6, characterized in that: In the catalytic hydrogenation reaction, the amount of catalyst used is 0.1-2 wt% of the mass of 4,4'-MDA.

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