A method for the hydrogenation synthesis of 1,3-cyclohexanedimethylamine from m-phenylenediamine

Abstract

This invention provides a simple and feasible method for the hydrogenation synthesis of 1,3-cyclohexanedimethylamine from m-phenylenediamine. The method achieves a m-phenylenediamine conversion rate of over 80% and a 1,3-cyclohexanedimethylamine selectivity of over 99.6%. It has advantages such as easy reaction operation, easy product separation, reusable catalyst, simple equipment, low total investment, low production cost, and high product purity.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical technology and relates to the production process of resin curing agents, particularly a method for synthesizing 1,3-cyclohexanedimethylamine by hydrogenation of m-phenylenediamine. Background Technology

[0002] 1,3-Cyclohexanedimethylamine, an important intermediate in organic and fine chemicals, possesses advantages such as high low-temperature curing activity and low toxicity. It is widely used in fields such as tile grout and automotive composite materials, and is also a crucial raw material for the synthesis of isocyanates. Currently, there are no domestic production facilities for it, and all 1,3-cyclohexanedimethylamine used in China must be imported, resulting in significant annual foreign exchange expenditures.

[0003] CN202010267205.1 A catalyst for the hydrogenation of m-phenylenediamine, its preparation method, and its application. This invention provides a catalyst for the hydrogenation of m-phenylenediamine to 1,3-cyclohexanedimethylamine and its preparation method. The catalyst consists of a support, an active component attached to the support, and an auxiliary agent. The active component is selected from one or more of metals Rh, Pt, Pd, Ir, Au, Ag, Ni, and Re, combined with a noble metal Ru. The auxiliary agent consists of auxiliary agent one and auxiliary agent two. Auxiliary agent one consists of metals Eu and Yb, and auxiliary agent two is selected from one or more of metals Li, Na, K, Cu, Co, Fe, Zn, Mn, La, and Ce. The support is a molecular sieve modified with metal compounds. Compared with the prior art, this catalyst can achieve higher feed conversion and 1,3-cyclohexanedimethylamine selectivity at lower reaction temperatures and pressures, higher substrate concentrations, and higher reaction space velocities. Furthermore, the catalyst is stable and has a long lifespan, which can significantly improve production efficiency and reduce production costs, thus facilitating industrial application.

[0004] CN201110072138.9 A catalyst for the hydrogenation of m-phenylenediamine to 1,3-cyclohexanedimethylamine under ammonia-containing conditions. This invention discloses a catalyst for the hydrogenation of m-phenylenediamine to 1,3-cyclohexanedimethylamine under ammonia-containing conditions. The catalyst provided by this invention, which converts m-phenylenediamine and hydrogen to 1,3-cyclohexanedimethylamine under ammonia-containing reaction conditions, consists of three parts: a main active component, an auxiliary agent, and a support. The main active component is a noble metal Ru and / or Pd. The auxiliary agent is one or more metals or oxides such as Ni, Cr, Co, and Fe. The support is selected from Al2O3, activated carbon, or SiO2, etc. In a fixed-bed reactor, under certain temperature, ammonia pressure, and the action of this catalyst, m-phenylenediamine and hydrogen can be converted with high activity and high selectivity into various amine products, with 1,3-cyclohexanedimethylamine as the main product.

[0005] CN201910171009.1 A catalyst for the selective hydrogenation of m-phenylenediamine to 1,3-cyclohexanedimethylamine. This invention discloses a catalyst for the hydrogenation of m-phenylenediamine to 1,3-cyclohexanedimethylamine, its preparation method, and its application. Belonging to the field of hydrogenation catalysts, the catalyst prepared by precipitation has suitable pores. With the addition of suitable additives, a synergistic effect is achieved. Combined with a unique catalyst preparation process, the catalyst exhibits high activity, resistance to pore blockage, and long service life. The conversion rate of m-phenylenediamine reaches 99.5%, and the selectivity for 1,3-cyclohexanediamine reaches 96.5%. Furthermore, the catalyst preparation method is simple, low-cost, and suitable for industrial production.

[0006] CN202210124105.2 discloses a trickle bed reactor with elastic packing and a method for preparing 1,3-cyclohexanedimethylamine therefrom. This invention discloses a trickle bed reactor with elastic packing, wherein the reactor bed is packed with three-dimensional elastic packing, at least one section of glass spring packing, at least one section of catalyst bed, and inert ceramic balls. The three-dimensional elastic packing penetrates the reactor bed, the glass spring packing and the catalyst bed are sequentially packed within the reactor bed, and the inert ceramic balls are packed at the top of the reactor bed. The trickle bed reactor of this invention, under the combined action of the two types of elastic packing, enhances the mass and heat transfer between the gas, liquid, and solid phases. The flow pattern within the bed approaches pulsed flow at relatively low gas-liquid flow rates, which is beneficial for increasing the space velocity of the device and reducing the reaction temperature and pressure. This invention also provides the application of the above-mentioned trickle bed reactor in catalytic hydrogenation reactions, particularly a method for preparing 1,3-cyclohexanedimethylamine by hydrogenation of m-phenylenediamine.

[0007] In summary, the main problems with the existing technology are: (1) The low mass hourly space velocity of m-phenylenediamine results in a large amount of catalyst and high investment cost. (2) The low concentration of the reaction substrate results in low production efficiency per unit volume of reactor and high energy consumption for solvent separation, which increases production cost. (3) The reaction conditions are harsh. In order to obtain a high yield of 1,3-cyclohexanedimethylamine, liquid ammonia or other small molecule organic amines are generally used as reaction solvents, or inorganic bases are used to modify the catalyst. The hydrogenation reaction is carried out under high temperature and high pressure, which poses a high safety risk and is prone to material leakage, causing environmental pollution. (4) The hydrogenation catalysts researched by various domestic research units have complex preparation processes and high costs, making it difficult to achieve industrialization in a short period of time. Summary of the Invention

[0008] Based on the above problems, this invention utilizes platinum-palladium-carbon, a commonly used catalyst in the market, as the main catalyst and iridium iodide as the co-catalyst, thus solving the catalyst preparation problem. Moreover, platinum-palladium-carbon can be recycled. Under this catalytic system, there is a very high selectivity for the target product, which is beneficial for the separation of raw materials and target products. Unreacted raw materials after separation can continue to be used.

[0009] This invention develops and records a method for synthesizing 1,3-cyclohexanedimethylamine by hydrogenation of m-phenylenediamine. The method uses a commercially available platinum-palladium-carbon catalyst with a certain platinum-palladium content as the main catalyst and iridium iodide as the co-catalyst. By leveraging the synergistic function of the two catalysts, the conversion rate of the raw material m-phenylenediamine is appropriately reduced to achieve a very high selectivity for the target product 1,3-cyclohexanedimethylamine.

[0010] The main technical solution of this invention is a method for synthesizing 1,3-cyclohexanedimethylamine by hydrogenation of m-phenylenediamine, characterized by using m-phenylenediamine as raw material, platinum palladium on carbon as the main catalyst, and iridium iodide as the co-catalyst to synthesize 1,3-cyclohexanedimethylamine by hydrogenation.

[0011] Generally, the amount of the main catalyst added is 5% to 12% of the weight of m-phenylenediamine.

[0012] The main catalyst, platinum-palladium-carbon, has a particle size of 100-20 mesh, a platinum content of 2.0%-3.0%, and a palladium content of 8%-10%.

[0013] The amount of the co-catalyst added is 1% to 3% of the weight of m-phenylenediamine.

[0014] The process employs a slurry-bed hydrogenation reactor.

[0015] The hydrogenation is carried out in a batch reaction.

[0016] The temperature of the catalytic hydrogenation reaction is 130℃~180℃.

[0017] The pressure of the catalytic hydrogenation reaction is 8.0 MPa to 10.0 MPa.

[0018] The catalytic hydrogenation reaction takes 10-12 hours.

[0019] The synthesis method provided by this invention achieves a conversion rate of over 80% for m-phenylenediamine and a selectivity of over 99.6% for 1,3-cyclohexanedimethylamine.

[0020] Beneficial effects: This invention uses a commercially available platinum-palladium carbon catalyst with a certain platinum-palladium content as the main catalyst and iridium iodide as the co-catalyst. It is a simple and feasible method for the hydrogenation of m-phenylenediamine to 1,3-cyclohexanedimethylamine. The reaction is easy to operate, the product is easy to separate, the catalyst can be reused, the equipment is simple, the total investment is low, the production cost is low, and the product purity is high. Detailed Implementation

[0021] The technical solution of the present invention will be further described below in conjunction with embodiments.

[0022] Example 1

[0023] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 3 g of platinum (2% content), palladium (8% content), 100 mesh platinum-palladium carbon, and 0.6 g of iridium iodide were added. The reactor was purged with nitrogen at 0.2 MPa three times and hydrogen at 0.2 MPa three times. Then, hydrogen was introduced to raise the temperature, which was controlled at 130 °C and the pressure at 8.0 MPa. The reaction was carried out at this pressure and temperature for 10 h. After the reaction was completed, the temperature was lowered and the pressure was released. The catalyst was filtered, and the filtrate was sampled and calculated. The conversion rate of m-phenylenediamine was 80.0%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.60%.

[0024] Example 2

[0025] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 4 g of platinum (2% content), palladium (8% content), 100 mesh platinum-palladium carbon, and 0.7 g of iridium iodide were added. The reactor was purged with nitrogen at 0.2 MPa three times and hydrogen at 0.2 MPa three times. Then, hydrogen was introduced to raise the temperature to 140 °C and the pressure to 8.0 MPa. The reaction was carried out at this pressure and temperature for 11 h. After the reaction was completed, the temperature was lowered and the pressure was released. The catalyst was filtered, and the filtrate was sampled and calculated. The conversion rate of m-phenylenediamine was 81.2%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.70%.

[0026] Example 3

[0027] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 7.2 g of platinum (2%), palladium (10%), 200-mesh platinum-palladium-carbon, and 1.8 g of iridium iodide were added. The reactor was purged three times with nitrogen at 0.2 MPa and three times with hydrogen at 0.2 MPa. Hydrogen was then introduced to raise the temperature to 180 °C and maintain a pressure of 10.0 MPa. The reaction was carried out at this pressure and temperature for 12 h. After the reaction was completed, the temperature was lowered and the pressure released. The catalyst was filtered, and samples of the filtrate were taken. The conversion rate of m-phenylenediamine was 90.0%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.90%.

[0028] Example 4

[0029] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine was added. The catalyst filtered out in Example 6 was used. The reactor was purged with nitrogen at 0.2 MPa three times and hydrogen at 0.2 MPa three times. Hydrogen was then introduced to raise the temperature, which was controlled at 140 °C and 8.5 MPa. The reaction was carried out at this pressure and temperature for 11 h. After the reaction was completed, the temperature was lowered and the pressure was released. The catalyst was filtered, and the filtrate was sampled and calculated. The conversion rate of m-phenylenediamine was 89.6%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.82%.

[0030] Example 5

[0031] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 7.2 g of platinum (2%), palladium (10%), 100 mesh platinum-palladium carbon, and 1.8 g of iridium iodide were added. The reactor was purged with nitrogen at 0.2 MPa three times, followed by hydrogen purging at 0.2 MPa three times. Hydrogen was then introduced to raise the temperature to 150 °C and the pressure to 8.0 MPa. The reaction was carried out at this pressure and temperature for 12 h. After the reaction was completed, the temperature was lowered and the pressure was released. The catalyst was filtered, and the filtrate was sampled and calculated. The conversion rate of m-phenylenediamine was 88.5%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.82%.

[0032] Example 6

[0033] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 6 g of platinum (2%), palladium (8%), 150 mesh platinum-palladium carbon, and 1.0 g of iridium iodide were added. The reactor was purged with nitrogen at 0.2 MPa three times, followed by hydrogen purging at 0.2 MPa three times. Hydrogen was then introduced to raise the temperature to 130 °C and the pressure to 8.5 MPa. The reaction was carried out at this pressure and temperature for 10 h. After the reaction was completed, the temperature was lowered and the pressure was released. The catalyst was filtered, and the filtrate was sampled and calculated. The conversion rate of m-phenylenediamine was 85.7%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.76%.

[0034] Example 7

[0035] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 3.5 g of platinum (2%), palladium (8%), 150 mesh platinum-palladium carbon, and 1.0 g of iridium iodide were added. The reactor was purged with nitrogen at 0.2 MPa three times, followed by hydrogen purging at 0.2 MPa three times. Hydrogen was then introduced to raise the temperature to 130 °C and the pressure to 8.5 MPa. The reaction was carried out at this pressure and temperature for 10 h. After the reaction was completed, the temperature was lowered and the pressure was released. The catalyst was filtered, and the filtrate was sampled and calculated. The conversion rate of m-phenylenediamine was 82.5%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.66%.

[0036] Example 8

[0037] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 3.5 g of platinum (2%), palladium (8%), 150 mesh platinum-palladium carbon, and 1.0 g of iridium iodide were added. The reactor was purged with nitrogen at 0.2 MPa three times, followed by hydrogen purging at 0.2 MPa three times. Hydrogen was then introduced to raise the temperature to 130 °C and the pressure to 8.5 MPa. The reaction was carried out at this pressure and temperature for 10 h. After the reaction was completed, the temperature was lowered and the pressure was released. The catalyst was filtered, and the filtrate was sampled and calculated. The conversion rate of m-phenylenediamine was 82.5%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.66%.

[0038] Example 9

[0039] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 7.2 g of platinum (2%), palladium (8%), 100-mesh platinum-palladium-carbon, and 1.8 g of iridium iodide were added. The reactor was purged three times with nitrogen at 0.2 MPa and three times with hydrogen at 0.2 MPa. Hydrogen was then introduced to raise the temperature, which was controlled at 150 °C and the pressure at 8.0 MPa. The reaction was carried out at this pressure and temperature for 12 h. After the reaction was completed, the temperature was lowered and the pressure released. The catalyst was filtered, and samples of the filtrate were taken. The conversion rate of m-phenylenediamine was 89.6%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.80%.

[0040] Example 10

[0041] In a 100 mL slurry bed reactor, 60 g of m-phenylenediamine, 5.6 g of platinum (2.1%), palladium (8.5%), 120-mesh platinum-palladium-carbon, and 0.7 g of iridium iodide were added. The reactor was purged with nitrogen at 0.2 MPa three times and hydrogen at 0.2 MPa three times. Then, hydrogen was introduced to raise the temperature, which was controlled at 140 °C and 9.2 MPa. The reaction was carried out at this pressure and temperature for 10 h. After the reaction was completed, the temperature was lowered and the pressure was released. The catalyst was filtered, and the filtrate was sampled and calculated. The conversion rate of m-phenylenediamine was 86.3%, and the selectivity of 1,3-cyclohexanedimethylamine was 99.71%.

Claims

1. A method for synthesizing 1,3-cyclohexanedimethylamine by hydrogenation of m-phenylenediamine, characterized in that... Using m-phenylenediamine as a raw material, 1,3-cyclohexanedimethylamine is synthesized by hydrogenation with platinum-palladium-carbon as the main catalyst and iridium iodide as the co-catalyst. The particle size of the main catalyst, platinum-palladium-carbon, is 100-200 mesh, the platinum content is 2.0%-3.0%, and the palladium content is 8%-10%. The amount of the main catalyst added is 5%~12% of the weight of m-phenylenediamine; the amount of the co-catalyst added is 1%~3% of the weight of m-phenylenediamine; a slurry bed hydrogenation reactor is used, and hydrogenation is carried out in batch reaction; the temperature of the catalytic hydrogenation reaction is 130℃~180℃, and the pressure is 8.0Mpa~10.0Mpa.

2. The method according to claim 1, characterized in that... The catalytic hydrogenation reaction takes 10-12 hours.

3. The method according to claim 1, characterized in that... The conversion rate of m-phenylenediamine is over 80%, and the selectivity of 1,3-cyclohexanedimethylamine is over 99.6%.