A preparation method of hexamethylenediamine

Abstract

The present invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing hexamethylenediamine. The method comprises the following steps: using adiponitrile as a raw material, reacting it with hydrogen in the presence of a solid base and a catalyst to produce hexamethylenediamine with a yield of ≥95.0% and a purity of ≥99.9%. The method is simple to operate, environmentally friendly, and efficient, resulting in a high-quality product with promising application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing hexamethylenediamine. Background Art

[0002] Hexamethylenediamine is an important organic chemical intermediate, primarily used in the production of polyamides such as nylon 66 salt and nylon 610. It can also be used in the synthesis of diisocyanates, curing agents for epoxy and urea-formaldehyde resins, and organic crosslinking agents. With the continuous development of the synthetic fiber industry, the demand for hexamethylenediamine compounds is increasing worldwide, resulting in a significant gap between supply and demand in the market.

[0003] In the prior art, there are many reports on methods for synthesizing hexamethylenediamine. The main one is: Patent CN107805203A reports that uses adiponitrile as raw material and homemade nano-nickel and magnesium oxide as catalysts, with a yield of 70-80% and a product purity of up to 99%.

[0004] Patent CN112898164A reports a process where 5-hydroxymethylfurfural reacts with ammonia and hydrogen over a reductive amination catalyst to produce 2,5-dimethyltetrahydrofuran. A ring-opening reaction occurs over a hydrodeoxygenation catalyst to produce hexamethylenediamine. Selectivity is below 90%. This method requires the preparation of two catalysts and is characterized by demanding conditions (calcination temperature around 450°C, activation temperature 350°C for 6 hours), high safety and equipment requirements, and high investment and low efficiency.

[0005] Patent CN112939784A reports that adipaldehyde is produced by electrolysis of cyclohexene, which is then subjected to reductive amination with ammonia, hydrogen, and loaded nickel to produce hexamethylenediamine. The conversion rate can reach 98.7%, the two-step yield is 98.02%, and the purity is 95.14%-98.13%. However, the second step reaction requires a relatively high pressure (20-40 MPa), which places high demands on the reaction equipment.

[0006] Patent CN112979474A reports a catalytic method for the hydrogenation and ring-opening of 2,5-dicyanofuran to hexamethylenediamine, with product selectivity exceeding 95% and yields reaching 95%-98%. However, this method requires the preparation of a metal catalyst supported on an acidic support. The process requires the reaction with hydrogen at high temperatures (above 150°C), and the hydrogenation and ring-opening of 2,5-dicyanofuran is also carried out under high temperature conditions (above 150°C). This method presents problems such as complex operation and high energy consumption. Yu Weichen et al. (Molecular Catalysis. 2021.35, 252-262) reported a copper-modified Ni / Al2O3 catalyst. This catalyst does not require a base to suppress byproduct formation and achieves a maximum yield of 73%. Summary of the Invention

[0007] In order to solve the above problems, the present invention discloses a method for preparing hexamethylenediamine, which can achieve rapid, efficient and safe preparation of high-purity hexamethylenediamine.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] A method for preparing hexamethylenediamine comprises the following steps:

[0010] (1) Add adiponitrile, solid base, catalyst and solvent into the premixing kettle and stir to mix;

[0011] (2) Pumping the mixed materials in step (1) into a jet reactor, while introducing hydrogen and maintaining a certain pressure to carry out the reaction;

[0012] (3) After the reaction is completed, the reaction liquid is filtered out through a filter membrane, and the solid base and catalyst are returned to the premixing kettle for reuse. The filtrate is post-treated to obtain hexamethylenediamine.

[0013] Furthermore, the solvent in step (1) is one of methanol, ethanol, isopropanol or a combination thereof.

[0014] Furthermore, in step (1), the mass ratio of the solvent to adiponitrile is 1-3:1.

[0015] Furthermore, the catalyst in step (1) is one of Raney nickel and palladium carbon or a combination thereof.

[0016] Furthermore, in step (1), the mass ratio of the catalyst to adiponitrile is 0.001-0.005:1.

[0017] Furthermore, the solid base in step (1) is one of Na-Na2CO3 / γ-Al2O3 type solid base, Na-KOH / γ-Al2O3 type solid base, Cs2O / γ-Al2O3 type solid base or a combination thereof.

[0018] Furthermore, the amount of solid base used in step (1) is 1%-10% of the mass of adiponitrile.

[0019] Furthermore, in step (1), the stirring and mixing temperature is 25-30° C.; and the stirring and mixing time is 1-3 h.

[0020] Furthermore, the reaction device in step (2) is a self-priming jet reaction device, the nozzle diameter of which is 0.25mm-100mm, the length of the jet pipe is 100mm-500mm, the jet angle is 30-120°, the number of nozzles is 10-20, and it can be installed on the same plane or on different planes.

[0021] Furthermore, in step (2), the reaction temperature is 50-60° C., the reaction pressure is 0.5-2.0 MPa, and the reaction time is 0.5-1 h.

[0022] Furthermore, the injection speed in step (2) is 0.05-0.1m 3 / h.

[0023] Furthermore, the filter membrane in step (3) is an inorganic ceramic filter membrane.

[0024] The beneficial effects of the present invention are:

[0025] A jet flow reaction process has been developed to achieve rapid, low-pressure continuous reaction and effectively reduce the production of by-products.

[0026] Solid alkali is selected as an auxiliary agent, which can be used several times together with the catalyst, reducing costs and effectively preventing strong alkali from corroding the reaction equipment.

[0027] In step (3), the filter membrane is an inorganic ceramic filter membrane, which is corrosion-resistant, prolongs the life of the catalyst, and can be used repeatedly and continuously.

[0028] Compared with the existing process, this process has higher selectivity, lower cost and higher yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a simplified process flow diagram for synthesizing hexamethylenediamine;

[0030] Figure 2 This is the gas phase spectrum of hexamethylenediamine synthesized in Example 1 of the present invention. Implementation Method

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0032] The process flow chart is as follows Figure 1 As shown; adiponitrile, solvent, base, and catalyst are added to a premixing kettle and stirred and mixed, and then the materials in the premixing kettle are pumped into the jet reactor, and hydrogen is introduced into the jet reactor at the same time. After the reaction is completed, the materials in the jet reactor are filtered through a filter, and the filtrate enters the post-processing system, and the filtered solid base and catalyst are returned to the premixing kettle. Example

[0033] Step (1): Add 108 kg of adiponitrile, 216 kg of ethanol, 0.216 kg of Raney nickel, and 5.4 kg of Na-Na2CO3 / γ-Al2O3 type solid base into a premixing kettle and stir at 30°C for 2 h.

[0034] Step (2): Introduce hydrogen into the 50L jet reactor, maintain the pressure at 2.0MPa, start the circulation pump and pump the above materials at 0.05m 3 The flow rate of the spray reactor is 1 / h, and the temperature in the reactor is controlled at 50° C. The nozzles in the spray reactor are installed in two layers, with 20 nozzles.

[0035] Step (3): After the materials are mixed, the reaction liquid is filtered through a filter, and the catalyst and solid base are returned to the premixing kettle. The filtrate is post-treated to obtain 111.42 kg of hexamethylenediamine with a yield of 96%.

[0036] The gas phase spectrum of the obtained hexamethylenediamine is as follows Figure 2 As shown, the purity is 99.98%.

[0037] After the catalyst and solid base were used 5 times, 110.72 kg of hexamethylenediamine was obtained with a yield of 95.4% and a purity of 99.9%. Example

[0038] Step (1): Add 108 kg of adiponitrile, 216 kg of isopropanol, 0.108 kg of Raney nickel, and 10.8 kg of Na-KOH / γ-Al2O3 type solid base into a premixing kettle and stir at 25°C for 3 hours.

[0039] Step (2): Introduce hydrogen into the 50L jet reactor, maintain the pressure at 1.8MPa, start the circulation pump and pump the above materials at 0.1m 3 The flow rate of the injector is 10 / h and the reaction temperature is controlled at 52°C. The nozzles in the injector are installed in two layers and there are 10 nozzles.

[0040] Step (3): After the materials are mixed, the reaction liquid is filtered through a filter, and the catalyst and solid base are returned to the premixing kettle. The filtrate is post-treated to obtain 111.19 kg of hexamethylenediamine with a yield of 95.8% and a purity of 99.96%.

[0041] After the catalyst and solid base were used 5 times, 111.42 kg of hexamethylenediamine was obtained with a yield of 96% and a purity of 99.94%. Example

[0042] Step (1): Add 108 kg of adiponitrile, 324 kg of methanol, 0.54 kg of palladium on carbon, and 5.4 kg of supported Cs2O solid base into a premixing kettle and stir at 25°C for 1 hour.

[0043] Step (2): Introduce hydrogen into the 50L jet reactor, maintain the pressure at 1.2MPa, start the circulation pump and pump the above materials at 0.1m 3 / h into the jet reactor, and the reaction temperature is controlled at 54 ° C. The nozzles in the jet reactor are installed in the same plane, and there are 20 nozzles.

[0044] Step (3): After the materials are mixed, the reaction liquid is filtered through a filter, and the catalyst and solid base are returned to the premixing kettle. The filtrate is post-treated to obtain 110.49 kg of hexamethylenediamine with a yield of 95.2% and a purity of 99.93%.

[0045] After the catalyst and solid base were used 5 times, 111.65 kg of hexamethylenediamine was obtained with a yield of 96.2% and a purity of 99.91%. Example

[0046] Step (1): Add 108 kg of adiponitrile, 108 kg of methanol, 0.108 kg of palladium carbon, and 10.8 kg of Na-Na2CO3 / γ-Al2O3 type solid base into a premixing kettle and stir at 25°C for 1 hour.

[0047] Step (2): Introduce hydrogen into the 50L jet reactor, maintain the pressure at 0.5MPa, start the circulation pump and pump the above materials at 0.05m 3 / h speed into the jet reactor, and the reaction temperature is controlled at 50 ° C. The nozzles in the jet reactor are installed in two layers, with 10 nozzles.

[0048] Step (3): After the materials are mixed, the reaction liquid is filtered through a filter, and the catalyst and solid base are returned to the premixing kettle. The filtrate is post-treated to obtain 110.84 kg of hexamethylenediamine with a yield of 95.5% and a purity of 99.96%.

[0049] After the catalyst and solid base were used 5 times, 111.53 kg of hexamethylenediamine was obtained with a yield of 96.1% and a purity of 99.93%. Example

[0050] Step (1): Add 108 kg of adiponitrile, 108 kg of ethanol, 0.324 kg of Raney nickel, and 1.08 kg of Na-Na2CO3 / γ-Al2O3 type solid base into a premixing kettle and stir at 30°C for 2 h.

[0051] Step (2): Introduce hydrogen into the 50L jet reactor, maintain the pressure at 1.0 MPa, start the circulation pump and pump the above materials at 0.05m 3 / h speed into the jet reactor, and the reaction temperature is controlled at 55 ° C. The nozzles in the jet reactor are installed in the same plane, and there are 20 nozzles.

[0052] Step (3): After the materials are mixed, the reaction liquid is filtered through a filter, and the catalyst and solid base are returned to the premixing kettle. The filtrate is post-treated to obtain 111.53 kg of hexamethylenediamine with a yield of 96.1% and a purity of 99.93%.

[0053] After the catalyst and solid base were used 5 times, 110.49 kg of hexamethylenediamine was obtained with a yield of 95.2% and a purity of 99.94%. Example

[0054] Step (1): Add 108 kg of adiponitrile, 324 kg of ethanol, 0.54 kg of Raney nickel, and 1.08 kg of Na-KOH / γ-Al2O3 type solid base into a premixing kettle and stir at 25°C for 3 hours.

[0055] Step (2): Introduce hydrogen into the 50L jet reactor, maintain the pressure at 1.5MPa, start the circulation pump and pump the above materials at 0.1m 3 / h speed into the jet reactor, and the reaction temperature is controlled at 60 ° C. The nozzles in the jet reactor are installed in two layers, with 10 nozzles.

[0056] Step (3): After the materials are mixed, the reaction liquid is filtered through a filter, and the catalyst and solid base are returned to the premixing kettle. The filtrate is post-treated to obtain 110.72 kg of hexamethylenediamine with a yield of 95.4% and a purity of 99.92%.

[0057] After the catalyst and solid base were used 5 times, 110.26 kg of hexamethylenediamine was obtained with a yield of 95% and a purity of 99.91%.

[0058] A hydrogenation reactor was charged with 108 kg of adiponitrile, 324 kg of ethanol, 0.54 kg of Raney nickel, and 1.08 kg of sodium hydroxide. After completion, the atmosphere was replaced with nitrogen and hydrogen three times, respectively. The temperature was then slowly raised to 70°C. The reaction was stirred at 3.5 MPa for 4 hours, and the pressure was released after completion. The reaction liquid was filtered and post-processed to obtain hexamethylenediamine. The yield was 81.7% and the purity was 99.88%. Sodium hydroxide cannot be used in this manner.

[0059] A hydrogenation reactor was charged with 108 kg of adiponitrile, 648 kg of ethanol, 1.08 kg of Raney nickel, and 2.16 kg of potassium hydroxide. After completion, the atmosphere was replaced with nitrogen and hydrogen three times, respectively. The temperature was then slowly raised to 70°C. The reaction was stirred at 4 MPa for 4 hours, and the pressure was released after completion. The reaction liquid was filtered and post-processed to obtain hexamethylenediamine. The yield was 86.2% and the purity was 99.72%. Potassium hydroxide cannot be used in a separate manner.

[0060] A hydrogenation reactor was charged with 108 kg of adiponitrile, 1080 kg of methanol, 0.108 kg of Raney nickel, and 5 kg of potassium hydroxide. After completion, the atmosphere was replaced with nitrogen and hydrogen three times, respectively. The temperature was then slowly raised to 65°C. The reaction was stirred at 4.5 MPa for 4 hours, and the pressure was released after completion. The reaction liquid was filtered and post-processed to obtain hexamethylenediamine. The yield was 83.6% and the purity was 99.85%. Potassium hydroxide cannot be used in a similar manner.

[0061] A hydrogenation reactor was charged with 108 kg of adiponitrile, 1080 kg of methanol, 0.108 kg of Raney nickel, and 5 kg of potassium hydroxide. After the additions were complete, the atmosphere was replaced with nitrogen and hydrogen three times, respectively. The temperature was then slowly raised to 60°C. The reaction was stirred at 3 MPa for 6 hours, and the pressure was released after completion. The reaction liquid was filtered and post-processed to obtain hexamethylenediamine. The yield was 81.3% and the purity was 99.76%. Potassium hydroxide cannot be used in a separate manner.

[0062] A hydrogenation reactor was charged with 108 kg of adiponitrile, 1080 kg of methanol, 10.8 kg of Raney nickel, and 5 kg of potassium hydroxide. After completion, the atmosphere was replaced with nitrogen and hydrogen three times, respectively. The temperature was then slowly raised to 50°C. The reaction was stirred at 4 MPa for 8 hours, and the pressure was released after completion. The reaction liquid was filtered and post-processed to obtain hexamethylenediamine. The yield was 78.5% and the purity was 99.8%. Potassium hydroxide cannot be used in a similar manner.

[0063] It should be noted that the above content merely illustrates the technical idea of ​​the present invention and cannot be used to limit the scope of protection of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing hexamethylenediamine, characterized in that: The following steps are involved: (1) Add adiponitrile, solvent, solid base and catalyst into a premixing kettle in a certain proportion and stir to mix; (2) Using a circulating pump, the material obtained in step (1) is injected into the reactor, and hydrogen is simultaneously turned on and maintained at a certain pressure to carry out the reaction; (3) After the reaction is completed, the reaction liquid is filtered out through a filter membrane, and the solid base and catalyst are put into a premixing kettle for reuse. The filtrate is post-treated to obtain hexamethylenediamine; The solid base in step (1) is one of Na-Na2CO3 / γ-Al2O3 type solid base, Na-KOH / γ-Al2O3 type solid base, Cs2O / γ-Al2O3 type solid base or a combination thereof; In step (1), the amount of solid base used is 1%-10% of the mass of adiponitrile; In step (1), the solvent is one or more of methanol, ethanol, and isopropanol; the catalyst is Raney nickel; In step (1), the stirring and mixing temperature is 25-30°C; the stirring and mixing time is 1-3 hours; The reaction device used in step (2) is a self-priming spray reaction device, the nozzle diameter of which is 0.25mm-100mm, the spray pipe length is 100mm-500mm, the spray nozzle angle is 30-120°, the number of nozzles is 10-20, and it can be installed on the same plane or on different planes; In step (2), the reaction pressure is 0.5-2.0 MPa, the reaction temperature is 50-60°C, and the reaction time is 0.5-1 h; In step (2), the injection speed is 0.05-0.1m 3 / h; In step (3), the filter membrane is an inorganic ceramic filter membrane.

2. The method for preparing hexamethylenediamine according to claim 1, wherein: In step (1), the mass ratio of the solvent to adiponitrile is 1-3:

1.

3. The method for preparing hexamethylenediamine according to claim 1, wherein: In step (1), the mass ratio of the catalyst to adiponitrile is 0.001-0.005:1.

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