Method for preparing 4, 4 '-diamino-dicyclohexylmethane with high trans-trans isomer content by using micro-packed bed

Abstract

The invention provides a method for preparing high trans-trans isomer content 4, 4 '-dihydroxybenzaldehyde by using a micro-packed bed. The invention relates to a method for preparing 4, 4 '-diamino-dicyclohexylmethane, which comprises the following steps: preparing 4, 4'-diamino-dicyclohexylmethane from 4, 4-diamino diphenylmethane (MDA) in a micropacked bed reactor under the action of a catalyst, the yield is 90% or more, the MDA conversion rate is 100%, the trans-body content is 55% or more, the preparation process is simple and easy to operate, the safety is high, the reaction time is short, and the method is suitable for industrial production. The method is suitable for large-scale industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of organic compound preparation, and specifically relates to a method for preparing 4,4'-diamino-dicyclohexylmethane with high trans-trans isomer content by using 4,4-diaminodiphenylmethane (MDA) as a raw material and utilizing a micro-packed bed. Background Art

[0002] H 12 MDA (4,4'-diamino-dicyclohexylmethane) is an important organic intermediate of alicyclic amines. Its main use is to prepare a new generation of anti-aging polyurethane dicyclohexylmethane diisocyanate (H 12 MDI), this type of isocyanate is suitable for preparing lightweight, stable performance polyurethane coatings and paints; H 12 MDA can also be used as a curing agent for epoxy resin.

[0003] Industrial 12 MDA is usually made from MDA (4,4'-diaminodiphenylmethane) as raw material, through high temperature and high pressure hydrogenation and purification under the action of catalyst. 12 MDA has three stereoisomers with different thermodynamic properties: trans / trans, cis / trans, and cis / cis. The composition of the isomers determines the properties and uses of the product. 12 The isomer content distribution of MDA in equilibrium state is trans-trans 50%, cis-trans 43%, and cis-cis 7%. Among the three isomers, the trans-trans isomer is the most thermodynamically stable, and high temperature reaction is conducive to its formation. After hydrogenation reaction, a mixture of the three isomers is obtained, and H 12 It is difficult to separate MDA stereoisomer mixtures in industry.

[0004] The trans-trans isomer content is about 20% 12 MDA is called H 12 MDA-20, trans-trans isomer content is about 50% H 12 MDA is called H 12 MDA-50, H 12 MDA-20 is mainly used to prepare polyurethane coatings with stable performance. 12 MDA-50 is mainly used to prepare aliphatic polyamide resin. From the perspective of material structure, when the size of the polymer material crystal is lower than the wavelength of the light wave, it allows the minimum scattering of the projected light to pass through, which is an effective way to improve the mechanical properties of the material and meet the requirements of special optical properties. 12 Microcrystalline transparent nylon prepared by MDA-50 is a new type of nylon that combines the high stress cracking resistance and chemical resistance of crystalline polymers with good thermal stability and optical properties, and has broad market application prospects.

[0005] US Patent No. 2494563 provides a method for producing high-anti-H 12 The method for isomerization of MDA uses ruthenium dioxide as a catalyst and dioxane or ethanol as a solvent to reduce 4,4'-diaminodiphenylmethane.

[0006] U.S. Patent No. 3,347,917 provides a method for selectively reducing 4,4'-diaminodiphenylmethane to generate an anti-isomer with a maximum content of 54.2 wt%. The method uses 0.1-10 wt% of a ruthenium catalyst and 5-40 wt% of ammonia, isopropyl ether or cyclohexane as a solvent, and hydrogenates at high temperature and high pressure for 1-30 minutes.

[0007] Chinese patent CN1970528 provides a lithium aluminate-based ruthenium-containing catalyst, which can hydrogenate and reduce aromatic amine compounds to alicyclic amines with high trans-content in a solvent or diluent at high temperature and high pressure.

[0008] US Patent No. 3711550 provides a method for changing H 12 The method for measuring the content of various isomers in MDA uses 0.01-1wt% of solid-supported Ru / Al2O3 as a catalyst and 0.5-10wt% of sodium hydroxide or sodium carbonate as an auxiliary agent, reacts under a certain hydrogen partial pressure and high temperature in an inert organic solvent, and can change the content ratio of the three isomers.

[0009] The preparation method disclosed in the above prior art has the following defects:

[0010] 1. The content of trans-trans isomer in the final product is low;

[0011] 2. The MDA conversion rate and target product yield are low;

[0012] 3. The reaction process is complicated and costly, which is not conducive to industrial production. Summary of the invention

[0013] In view of the above shortcomings in the prior art, the present invention provides a method for preparing 4,4'-diamino-dicyclohexylmethane with high trans-trans isomer content by using a micro-packed bed. The trans-trans isomer content of the prepared 4,4'-diaminodicyclohexylmethane is 55-60%.

[0014] To achieve the above purpose, the technical solution of the present invention is as follows:

[0015] A method for preparing 4,4'-diamino-dicyclohexylmethane with a high trans-trans isomer content by using a micro-packed bed, comprising:

[0016] Step 1: dissolving 4,4'-diaminodiphenylmethane in an organic solvent;

[0017] Step 2: Load the catalyst into the micro-packed bed reactor, connect the components and the connecting pipes between them, start the refrigeration and heating circulator, heat the reactor and control the temperature;

[0018] Step 3: Pump the mixed solution of step 1 into the reactor, introduce inert gas into the reactor, and after exhausting the air in the reactor, switch to hydrogen gas to control the pressure and temperature in the reactor. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation.

[0019] Furthermore, in step 1, the organic solvent is selected from any one or more of ethanol, tert-butanol, tetrahydrofuran, 1,4-dioxane, cyclopentane, ethylene glycol, n-propanol, and n-butanol, preferably 1,4-dioxane and tetrahydrofuran.

[0020] Furthermore, the catalyst in step 2 is selected from any one of Co2O3, CaO, Na2CO3, Ru, Rh, Ru / LiAlO2, and Ru / Al2O3, preferably Ru / LiAlO2.

[0021] Furthermore, in step 1, the ratio of 1,4-dioxane to tetrahydrofuran is 15-40%:60-90%, preferably 30%:70%.

[0022] Furthermore, in step 2, the concentration of the catalyst Ru / LiAlO2 is 1wt% to 5wt%, preferably 3wt%.

[0023] Furthermore, in step 3, the mixed solution is pumped in at a mass space velocity of 0.15 to 0.30 g / g, most preferably 0.20 g / g.

[0024] Furthermore, in step 3, the temperature in the reactor is controlled to be 100-150°C, preferably 120°C.

[0025] Furthermore, in step 3, the pressure in the reactor is controlled to be 9-15 MPa, preferably 12 MPa.

[0026] Furthermore, the reaction process adopts continuous operation.

[0027] Beneficial Effects

[0028] 4,4'-diaminodicyclohexylmethane is prepared in a micro-packed bed reactor using 4,4-diaminodiphenylmethane (MDA) as a raw material under the action of a catalyst. The yield of the 4,4'-diaminodicyclohexylmethane is 99-100%, the MDA conversion rate is 100%, the trans-isomer content is more than 55%, and the preparation process is simple and easy to operate, with high safety and short reaction time, and is suitable for large-scale industrial production. DETAILED DESCRIPTION

[0029] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0030] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0031] Instruments and test, analysis methods

[0032] Agilent 7890A gas chromatograph was used to analyze the H in the raw materials and hydrogenation mixed products. 12 For the quantitative analysis of MDA, etc., the chromatographic analysis conditions of the samples are as follows: HP-5 chromatographic column (60m×0.25mm×0.25μm), hydrogen flame ionization detector (FID), detector temperature 270℃, H2 flow rate 25mL / min, air flow rate 300mL / min; carrier gas is N2; pure sample injection, injection volume 0.3μL; vaporization chamber temperature 270℃, split ratio 100:1.

[0033] Embodiment 1:

[0034] Weigh 500g of 4,4'-diaminodiphenylmethane (MDA) and mix it with 3500mL of 1,4-dioxane-tetrahydrofuran solution (3:7) and stir it thoroughly to dissolve it to obtain a raw material mixed solution. Load 30g of Ru / LiAlO2 (3wt%) into a micro-packed bed reactor, connect the connecting pipes between the various components of the device, and pump the mixed solution into the reactor at a raw material mass space velocity of 0.20g / g through a metering pump. Nitrogen is introduced into the reactor. After the air in the reactor is exhausted, it is switched to hydrogen. The pressure in the reactor is maintained at 12.00MPa and the temperature is 120°C for reaction. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation. The reaction liquid after separation is taken for HPLC analysis. The test results show that the MDA conversion rate is 100%, the yield is 99.57%, and the trans-isomer content is 58.75%.

[0035] Embodiment 2:

[0036] Weigh 500g of 4,4'-diaminodiphenylmethane (MDA) and mix it with 3500mL of 1,4-dioxane-tetrahydrofuran solution (3:7) and stir it thoroughly to dissolve it to obtain a raw material mixed solution. Load 30g of Ru / LiAlO2 (5wt%) into a micro-packed bed reactor, connect the connecting pipes between the various components of the device, and pump the mixed solution into the reactor at a raw material mass space velocity of 0.20g / g through a metering pump. Pass nitrogen into the reactor, exhaust the air in the reactor, and switch to hydrogen. Maintain the pressure in the reactor at 12.00MPa and the temperature at 100°C for reaction. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation. The separated reaction liquid is taken for HPLC analysis. The test results show that the MDA conversion rate is 100%, the yield is 99.31%, and the trans-isomer content is 58.23%.

[0037] Embodiment 3:

[0038] Weigh 500g of 4,4'-diaminodiphenylmethane (MDA) and mix it with 3500mL of 1,4-dioxane-tetrahydrofuran solution (3:7) and stir it thoroughly to dissolve it to obtain a raw material mixed solution. Load 30g of Ru / LiAlO2 (1wt%) into a micro-packed bed reactor, connect the connecting pipes between the various components of the device, and pump the mixed solution into the reactor at a raw material mass space velocity of 0.15g / g through a metering pump. Pass nitrogen into the reactor, and after exhausting the air in the reactor, switch to hydrogen. Maintain the pressure in the reactor at 10.00MPa and the temperature at 150°C for reaction. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation. The separated reaction liquid is taken for HPLC analysis. The test results show that the MDA conversion rate is 100%, the yield is 99.12%, and the trans-isomer content is 57.53%.

[0039] Embodiment 4:

[0040] Weigh 500g of 4,4'-diaminodiphenylmethane (MDA) and mix it with 3500mL of 1,4-dioxane solution, stir it thoroughly and dissolve it to obtain a raw material mixed solution, load 30g of Ru / LiAlO2 (2wt%) into a micro-packed bed reactor, connect the connecting pipes between the various components of the device, and pump the mixed solution into the reactor at a raw material mass space velocity of 0.25g / g through a metering pump. Nitrogen is introduced into the reactor. After the air in the reactor is exhausted, it is switched to hydrogen. The pressure in the reactor is maintained at 13.00MPa and the temperature is 110°C for reaction. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation. The separated reaction liquid is taken for HPLC analysis. The test results show that the MDA conversion rate is 100%, the yield is 92.65%, and the trans-isomer content is 55.37%.

[0041] Embodiment 5:

[0042] Weigh 500g of 4,4'-diaminodiphenylmethane (MDA) and mix it with 3500mL of tetrahydrofuran solution, stir it thoroughly and dissolve it to obtain a raw material mixed solution, load 30g of Ru / LiAlO2 (1wt%) into a micro-packed bed reactor, connect the connecting pipes between the various components of the device, and pump the mixed solution into the reactor at a raw material mass space velocity of 0.25g / g through a metering pump. Nitrogen is introduced into the reactor. After the air in the reactor is exhausted, it is switched to hydrogen. The pressure in the reactor is maintained at 10.00MPa and the temperature is 120°C for reaction. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation. The separated reaction liquid is taken for HPLC analysis. The test results show that the MDA conversion rate is 100%, the yield is 90.50%, and the trans-isomer content is 55.14%.

[0043] Embodiment 6:

[0044] Weigh 500g of 4,4'-diaminodiphenylmethane (MDA) and mix it with 3500mL of ethanol solution, stir it thoroughly and dissolve it to obtain a raw material mixed solution, load 30g of Ru / Al2O3 (0.5wt%) into a micro-packed bed reactor, connect the connecting pipes between the various components of the device, and pump the mixed solution into the reactor at a raw material mass space velocity of 0.10g / g through a metering pump. Nitrogen is introduced into the reactor. After the air in the reactor is exhausted, it is switched to hydrogen. The pressure in the reactor is maintained at 5.00MPa and the temperature is 80°C for reaction. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation, and the separated reaction liquid is taken for HPLC analysis. The test results show that the MDA conversion rate is 98.76%, the yield is 89.37%, and the trans-antibody content is 33.48%.

[0045] Embodiment 7:

[0046] Weigh 500g of 4,4'-diaminodiphenylmethane (MDA) and mix it with 3500mL of tetrahydrofuran solution, stir it thoroughly and dissolve it to obtain a raw material mixed solution. Load 30g of Ru / Al2O3 (6wt%) into a micro-packed bed reactor, connect the connecting pipes between the various components of the device, and pump the mixed solution into the reactor at a raw material mass space velocity of 0.10g / g through a metering pump. Nitrogen is introduced into the reactor. After the air in the reactor is exhausted, it is switched to hydrogen. The pressure in the reactor is maintained at 8.00MPa and the temperature is 90°C for reaction. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation. The separated reaction liquid is taken for HPLC analysis. The test results show that the MDA conversion rate is 98.83%, the yield is 98.37%, and the trans-isomer content is 36.72%.

[0047] The above is a description of a specific embodiment of the present invention. It should be understood that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for illustrating the principles of the present invention. Those skilled in the art may make various non-substantial changes and improvements to the present invention without departing from the concept of the present invention, which all fall within the scope of the present invention.

Claims

1. A method for preparing 4,4'-diamino-dicyclohexylmethane with high trans-trans isomer content using a micro-packed bed, comprising: Step 1: dissolving 4,4'-diaminodiphenylmethane in an organic solvent; Step 2: Load the catalyst into the micro-packed bed reactor, connect the components and the connecting pipes between them, start the refrigeration and heating circulator, heat the reactor and control the temperature; Step 3: Pump the mixed solution of step 1 into the reactor, introduce inert gas into the reactor, and after exhausting the air in the reactor, switch to hydrogen gas to control the pressure and temperature in the reactor. After the reaction is completed, the feed liquid enters the separator for gas-liquid separation.

2. A method according to claim 1, characterized in that In step 1, the organic solvent is selected from any one or more of ethanol, tert-butanol, tetrahydrofuran, 1,4-dioxane, sulfolane, ethylene glycol, n-propanol, and n-butanol, preferably 1,4-dioxane and tetrahydrofuran.

3. A method according to claim 1, characterized in that The catalyst in step 2 is selected from any one of Co2O3, CaO, Na2CO3, Ru, Rh, Ru / LiAlO2, and Ru / Al2O3, preferably Ru / LiAlO2.

4. A method according to claim 2, characterized in that The ratio of 1,4-dioxane to tetrahydrofuran is 15-40%:60-90%, preferably 30%:70%.

5. A method according to claim 3, characterized in that The concentration of the catalyst Ru / LiAlO2 is 1 wt% to 5 wt%, preferably 3 wt%.

6. A method according to claim 1, characterized in that In step 3, the mixed solution is pumped in at a mass space velocity of 0.15 to 0.30 g / g, most preferably 0.20 g / g.

7. A method according to claim 1, characterized in that In step 3, the temperature in the reactor is controlled to be 100-150°C, preferably 120°C.

8. A method according to claim 1, characterized in that In step 3, the pressure in the reactor is controlled to be 9-15 MPa, preferably 12 MPa.

9. A method according to claim 1, characterized in that The reaction process adopts continuous operation.