A process for the production of hexanediamine by hydrogenation of a nitrile

Abstract

The application discloses a method for preparing hexamethylene diamine by hydrogenation of adiponitrile, which comprises the following steps: preparing a reaction solution by hydrogenation reaction of adiponitrile, and preparing the hexamethylene diamine by post-treatment; wherein the hydrogenation reaction system further comprises an adsorbent and mother liquor generated in the post-treatment process. By returning the mother liquor containing nitrogen heteroheptacycle Schiff base, amide and other impurities of the hydrogenation ammonia by-product to the reactor and adding the adsorbent in the reaction, the content of the reaction by-product AMCPA can be reduced to below 5 mg / kg, and the polarographic value of the hexamethylene diamine product is less than or equal to 20 mmol IB / t-HMD, compared with the production process without recycling the mother liquor according to the application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic synthesis, and particularly relates to a method for preparing hexamethylene diamine by hydrogenation of nitrile. BACKGROUND

[0002] Hexamethylene diamine (HMD) is a versatile compound, and is commonly used for preparing polyamides such as nylon 66 and hexamethylene diisocyanate.

[0003] At present, the main raw material for preparing hexamethylene diamine is adiponitrile, and the mainstream process route of adiponitrile includes butadiene cyanation, propylene cyanation electrolysis, and adipic acid ammoniation. All the above process routes contain an impurity iminocyclopentyl cyanide (ICCP), according to known documents or patents, for example, GB1367006, 2-aminomethylcyclopentylamine (AMCPA) generated by hydrogenation of ICCP is difficult to separate from hexamethylene diamine, and the impurity can cause low strength and high color number of nylon 66 as a downstream product.

[0004] On the other hand, in addition to the influence of AMCPA and other impurities on the quality of hexamethylene diamine, another key indicator of hexamethylene diamine is the polarographic value, and the impurities affecting the polarographic value mainly include nitrogen heteroheptyl Schiff base (THA), 6-aminohexanitrile, and amide. Among them, THA nitrogen heteroheptyl Schiff base is derived from two sources, one is generated from the reaction, and the other is generated by thermal decomposition of the material in the rectification process, so it is difficult to completely remove from the product by rectification method; amide is mainly generated from nitrile hydrolysis and ammoniation, both of which have an impact on the polarographic value of the product. The traditional control method is to discharge the tower bottom mother liquor containing the above-mentioned impurities, causing waste of the product.

[0005] Therefore, it is necessary to develop new technology to reduce the influence of impurities generated in the raw material introduction and rectification process on the quality of the product. SUMMARY

[0006] In view of the influence of impurities generated in the raw material introduction and rectification process on the quality of the product in the prior art, the purpose of the present application is to provide a method for preparing hexamethylene diamine by hydrogenation of nitrile, which returns the mother liquor generated in the post-treatment process to the reactor, and simultaneously adds an adsorbent. Compared with the production process without recycling the mother liquor by using the present application, the content of by-product AMCPA in the hydrogenation reaction liquid can be reduced to below 5 mg / kg, and the polarographic value of the hexamethylene diamine product is ≤20 mmol IB / t-HMD.

[0007] To achieve the above-mentioned purpose of the application, the technical solution adopted by the present application is as follows:

[0008] A method for preparing hexamethylene diamine by hydrogenation of nitrile, which comprises the following steps: hydrogenation reaction of adiponitrile to obtain a reaction liquid, and then post-treatment to obtain the product; wherein the hydrogenation reaction system further comprises an adsorbent and a mother liquor generated in the post-treatment process.

[0009] In an embodiment, the mother liquor produced by the post-treatment process mainly contains hexamethylene diamine, cyclohexylideneimine, 1,2-cyclohexanediamine, N-ethylhexanediamine, Schiff base, amide, etc.; wherein the Schiff base is mainly azepine Schiff base, and the amide is mainly valeramide, caproamide, adipamide, etc.

[0010] Specifically, the mother liquor contains 10-5000 mg / kg of azepine Schiff base and 10-5000 mg / kg of amide. In detail, the content of azepine Schiff base includes but is not limited to 10 mg / kg, 30 mg / kg, 50 mg / kg, 100 mg / kg, 500 mg / kg, 1000 mg / kg, 1500 mg / kg, 2000 mg / kg, 2500 mg / kg, 3000 mg / kg, 3500 mg / kg, 4000 mg / kg, 4500 mg / kg, 5000 mg / kg or a range between any two of them, and the content of amide includes but is not limited to 10 mg / kg, 30 mg / kg, 50 mg / kg, 100 mg / kg, 500 mg / kg, 1000 mg / kg, 1500 mg / kg, 2000 mg / kg, 2500 mg / kg, 3000 mg / kg, 3500 mg / kg, 4000 mg / kg, 4500 mg / kg, 5000 mg / kg or a range between any two of them.

[0011] The mother liquor produced by the post-treatment process is obtained by post-treatment of the reaction liquid produced by the hydrogenation reaction of adiponitrile. The mother liquor produced by the post-treatment process can be directly returned to the reactor for recycling to participate in the hydrogenation reaction through a bypass, or can be recovered and used in the next batch of reactions, or can be collected and stored for use in other production lines, and the present application does not have special requirements therefor.

[0012] In some specific implementation processes, the post-treatment process includes desolventization, dewatering, decoking, light removal, refining and the like. Correspondingly, the mother liquor produced by the post-treatment process after each process includes but is not limited to desolventization mother liquor, dewatering mother liquor, decoking mother liquor, product column bottom mother liquor, etc.

[0013] In an embodiment, the post-treatment process finally obtains hexamethylene diamine from the product column top, and the total content of azepine Schiff base and amide in the product column bottom mother liquor is ≤500 mg / kg, for example, including but not limited to 500 mg / kg, 450 mg / kg, 400 mg / kg, 350 mg / kg, 300 mg / kg, 250 mg / kg, 200 mg / kg, 150 mg / kg, 100 mg / kg, 50 mg / kg, 30 mg / kg, 20 mg / kg, 10 mg / kg, 1 mg / kg or not detected, etc.

[0014] In an embodiment, the mother liquor produced by the post-treatment process is added in an amount of 0.01 to 50 wt% of the adiponitrile feed, including but not limited to 0.01 wt%, 0.1 wt%, 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt% or a range between any two of these values, preferably 1 to 20 wt%.

[0015] In an embodiment, the adsorbent is selected from one or more of magnesium oxide (nano magnesium oxide), activated alumina, diatomite, calcium carbonate, activated carbon, and the like,

[0016] Preferably, the pH of the adsorbent can be 7.0 to 14.0, including but not limited to 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0 or a range between any two of these values, preferably 8 to 12;

[0017] Preferably, the specific surface area of the adsorbent can be 50 to 500 m 2 / g, including but not limited to 50 m 2 / g, 100 m 2 / g, 150 m 2 / g, 200 m 2 / g, 250 m 2 / g, 300 m 2 / g, 350 m 2 / g, 400 m 2 / g, 450 m 2 / g, 500 m 2 / g or a range between any two of these values, preferably 100 to 300 m 2 / g.

[0018] Preferably, the BET pore size of the adsorbent can be 3 to 100 nm, including but not limited to 3 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm or a range between any two of these values, preferably 5 to 20 nm.

[0019] Preferably, the average particle size of the adsorbent can be 10 to 1000 um, including but not limited to 10 um, 50 um, 100 um, 200 um, 300 um, 400 um, 500 um, 600 um, 700 um, 800 um, 900 um, 1000 um or a range between any two of these values, preferably 20 to 80 um.

[0020] In an embodiment, the adsorbent is added in an amount of 0.01-1 wt% of the adiponitrile feed, including but not limited to 0.01 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, or a range between any two of them, preferably 0.005-0.05 wt%.

[0021] The method for preparing hexamethylene diamine by hydrogenation of nitrile according to the present application, the raw material of adiponitrile can be obtained by conventional methods in the art, such as commercially available or self-made adiponitrile by conventional methods in the art, the self-made method can be butadiene method, acrylonitrile method, adipic acid method, etc.; limited by the preparation process and other factors, the commercially available or self-made raw material of adiponitrile usually contains trace amount of impurity iminocyclopentyl cyanide (ICCP), generally speaking, the commercially available or self-made raw material of adiponitrile usually contains 10-100 mg / kg of ICCP. 2-aminomethylcyclopentylamine (AMCPA) generated by hydrogenation of ICCP is difficult to separate from hexamethylene diamine, and the impurity will cause the strength of downstream products such as nylon 66 to decrease and the color number to increase.

[0022] The present application experiment found that by adding a certain amount of adsorbent to the reaction, the impurities such as ICCP in the raw material, the impurities in the recovered mother liquor and the amide generated in the reaction can be enriched in the adsorbent channel at the reaction temperature by chemical adsorption, thereby avoiding the hydrogenation of impurities to generate undesirable by-product AMCPA, reducing the poisoning of the catalyst, and reducing the amount of by-products. At the same time, the nitrogen heteroheptacyclic Schiff base introduced in the recovered mother liquor can be hydrogenated to form cyclohexyl imine (HMI), which is easy to separate from the product, thereby reducing the polarographic value of the product.

[0023] In an embodiment, the hydrogenation reaction has a reaction temperature of 60-100℃, preferably 65-85℃; a reaction pressure of 1.5-5 MPa, preferably 2.0-3.5 MPa; specifically, the reaction temperature includes but is not limited to 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, or a range between any two of them; the reaction pressure includes but is not limited to 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, or a range between any two of them.

[0024] Preferably, the feed airspeed is 0.5-5 g / g cat. / h, for example including but not limited to 0.5 g / g cat. / h, 1 g / g cat. / h, 1.5 g / g cat. / h, 2 g / g cat. / h, 2.5 g / g cat. / h, 3 g / g cat. / h, 3.5 g / g cat. / h, 4 g / g cat. / h, 4.5 g / g cat. / h, 5 g / g cat. / h or a range consisting of any two of them; more preferably, the reaction is stopped after the reaction continues to keep warm for 5-30 min after the end of feeding, for example including but not limited to 5 min, 8 min, 10 min, 12 min, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min or a range consisting of any two of them;

[0025] In the above hydrogenation reaction process, the amount of hydrogen added satisfies the reaction pressure (i.e. hydrogen is charged into the reactor and the hydrogen is pressurized to the preset reaction pressure).

[0026] In one embodiment, the hydrogenation reaction system further comprises solvents, catalysts, adjuvants and the like raw materials;

[0027] Specifically, a method for preparing hexanediamine by hydrogenation of nitrile is to mix adiponitrile with solvents, catalysts, adjuvants, adsorbents and mother liquor produced in the post-processing process, introduce hydrogen for hydrogenation reaction to obtain a reaction liquid, and then prepare hexanediamine by desolventizing, dewatering, de-coking, de-light, refining and other post-processing. The related conditions of the reaction are limited in the foregoing. For other operations and process conditions in the preparation method of the present application and the devices used, corresponding conventional choices in the art can be used, and there is no special limitation. The skilled person can optimize them according to the actual needs based on the known processes in the prior art, and specifically, for example, the conditions listed in the following embodiments of the present application can be used.

[0028] In one embodiment, the catalyst is selected from one or more of skeletal nickel or skeletal cobalt catalysts, preferably a skeletal nickel catalyst;

[0029] Preferably, the amount of catalyst added is 5-50 wt% of the amount of adiponitrile, for example including but not limited to 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt% or a range consisting of any two of them, preferably 15-30 wt%.

[0030] In actual production process, part of catalysts need to be replaced periodically in the reactor to maintain the reaction activity, and in the process of catalyst discharge, the adsorbent in the system can be discharged together, and then the catalyst and adsorbent in the system are adjusted to the required amount.

[0031] In an embodiment, the solvent can be selected according to the conventional selection in the field, and there is no special requirement for its kind and amount, for example, the solvent can be one or more of methanol, ethanol, propanol, isopropanol, tetrahydrofuran and the like, preferably ethanol and / or methanol; preferably, the amount of solvent added is 0.2-5 times the mass of adiponitrile, for example, including but not limited to 0.2 times, 0.5 times, 1 times, 2 times, 3 times, 4 times, 5 times or a range consisting of any two of them.

[0032] In an embodiment, the auxiliary agent is selected from one or more of NaOH, KOH, CsOH, tetramethylammonium hydroxide and the like; preferably, the amount of auxiliary agent added is 0.1-5wt% of the amount of adiponitrile, for example, including but not limited to, for example, including but not limited to 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt% or a range consisting of any two of them or a range consisting of any two of them.

[0033] In an embodiment, according to the method for preparing hexamethylene diamine by hydrogenation of nitrile as described above, the hydrogenation reaction can be carried out using a conventional reactor in the field, for example, the reactor used can be a gas-liquid-solid three-phase fluidized bed reactor or a tank reactor, preferably a tank reactor.

[0034] After the hydrogenation reaction described above is stopped, the composition of the mother liquor is analyzed by sampling, and based on the mass percentage after removing the solvent, the content of byproduct AMCPA is reduced to below 5mg / kg.

[0035] After the hydrogenation reaction described above is stopped, further post-treatment such as desolventizing, dewatering, de-coking, de-light, refining and the like is carried out to prepare hexamethylene diamine, wherein the desolventizing, dewatering, de-coking, de-light, refining and the like are all conventional operations in the field, and the parameters can be designed commonly, which will not be described in detail. The polarographic value of the hexamethylene diamine product prepared in this way can be reduced to below 20mmol IB / t-HMD, and in the unit of polarographic value, IB represents isobutyraldehyde.

[0036] Compared with the prior art, the beneficial effects of the present application are as follows:

[0037] 1. By recycling the mother liquor generated in the post-treatment process into the reactor, the discharge of rectification mother liquor can be reduced, thereby reducing the waste of hexamethylene diamine product and improving the economic efficiency of the product.

[0038] 2. By adding adsorbent to the reaction system, the impurities such as ICCP and amide can be enriched in the adsorbent pores at the reaction temperature, thereby avoiding the hydrogenation of the impurities to generate the undesired by-product AMCPA and reducing the poisoning of the catalyst. At the same time, the impurity nitrogen heterocyclic heptane Schiff base can be converted into HMI by hydrogenation, which is easy to separate from the product, thereby obtaining a product with low polarographic value. DETAILED DESCRIPTION

[0039] In order to better understand the technical solutions of the present application, the following examples will further illustrate the method provided by the present application, but the present application is not limited to the listed examples, and any other known changes within the scope of the claims of the present application should also be included.

[0040] Unless otherwise specified, the reagents, materials, instruments and analysis methods used in the following examples are conventional reagents, conventional materials, conventional instruments and conventional analysis methods in the art, which can be obtained by commercial purchase, and the reagents involved can also be synthesized by conventional methods in the art. The specific conditions of the test methods not indicated in the following examples are conventional operating conditions.

[0041] The main raw material sources are as follows:

[0042]

[0043] The mother liquor produced by the post-treatment process of the hydrogenation reaction of adiponitrile, including desolventization, dehydration, de-coke, light removal, refining, etc., is as follows:

[0044] Desolventization mother liquor: nitrogen heterocyclic heptane Schiff base 125 mg / kg, amide content 4517 mg / kg;

[0045] Dehydration mother liquor: nitrogen heterocyclic heptane Schiff base 113 mg / kg, amide content 4871 mg / kg;

[0046] De-coke mother liquor: nitrogen heterocyclic heptane Schiff base 198 mg / kg, amide content 3846 mg / kg;

[0047] Product column mother liquor: nitrogen heterocyclic heptane Schiff base 98 mg / kg, amide content 2563 mg / kg;

[0048] Light removal mother liquor: nitrogen heterocyclic heptane Schiff base 87 mg / kg, amide content 2351 mg / kg.

[0049] The reaction liquid components in the following examples were analyzed by gas chromatography under the following conditions: Agilent DB-5 column, sample inlet temperature 280°C, FID detector temperature 300°C, column flow rate 1.5 ml / min, hydrogen flow rate 30 ml / min, air flow rate 400 ml / min, and programmed temperature rise from 50°C for 2 min, then 5°C / min to 80°C, then 15°C / min to 280°C, and then 10 min at 280°C.

[0050] The present application is further explained by more specific examples below, but does not constitute any limitation.

[0051] Example 1

[0052] Into a reaction kettle were added ethanol 300 g, NaOH 3 g, Raney nickel catalyst (wet weight) 30 g, magnesium oxide powder 0.1 g (pH = 8-10, average particle size 30 um, specific surface area 198 m 2 / g, pore size 5.6 nm), adiponitrile and desolventizing mother liquor at a space velocity of 0.5 g / g cat. / h, and hydrogen was introduced for hydrogenation reaction.

[0053] The reaction conditions were 85°C, 2.5 MPa, and the feed amount was adiponitrile 200 g and desolventizing mother liquor 40 g. After the feed was completed, the reaction was extended for 10 min and then stopped. The reaction liquid composition was analyzed, and the solvent accounted for, in which the HMD content was 98.8 wt%, and the AMCPA content was 1 mg / kg.

[0054] The reaction liquid was subjected to desolventizing, dewatering, decoking, light removal, and refining in sequence, and the product tower bottom mother liquor was obtained at the bottom of the product tower (i.e. product tower), in which the total content of THA and amide was 426 mg / kg. The adipodiamine product was obtained from the top of the tower, and the polarographic value was 15 mmol IB / t-HMD.

[0055] Example 2

[0056] Into a reaction kettle were added methanol 300 g, KOH 6 g, Raney nickel catalyst (wet weight) 60 g, activated carbon powder 0.02 g (pH = 7-10, average particle size 300 um, specific surface area 495 m 2 / g, pore size 3 nm), adiponitrile and dewatering mother liquor at a space velocity of 1.5 g / g cat. / h, and hydrogen was introduced for hydrogenation reaction.

[0057] The reaction conditions were 60°C, 5 MPa, and the feed amount was adiponitrile 200 g and dewatering mother liquor 32 g. After the feed was completed, the reaction was extended for 5 min and then stopped. The reaction liquid composition was analyzed, and the solvent accounted for, in which the HMD content was 99.0 wt%, and the AMCPA content was 3 mg / kg.

[0058] The reaction liquid is successively subjected to desolventizing, dewatering, decoking, light component removal, and refining to obtain product bottom liquid at the bottom of the refining column, wherein the total content of THA and amide is 357 mg / kg, and the hexamethylene diamine product is obtained from the top of the column, with a polarographic value of 10 mmol IB / t-HMD.

[0059] Example 3

[0060] Into the reaction kettle are added 300 g of ethanol, 2 g of CsOH, 20 g of Raney nickel catalyst (wet weight), 1 g of γ-alumina powder (pH = 7-8, average particle size 10 um, specific surface 70 m 2 / g, pore size 9 nm), adiponitrile, and decoking mother liquor are fed at a space velocity of 2.5 g / g cat. / h, and hydrogen is introduced for hydrogenation reaction.

[0061] The reaction conditions are: 71°C, 4.6 MPa, the feeding amount is 200 g of adiponitrile and 20 g of decoking mother liquor, after the feeding is completed, the reaction is stopped after being extended for 15 min, the reaction liquid composition is analyzed by sampling, and the solvent removal ratio, wherein the HMD content is 98.7 wt%, and the AMCPA content is 4 mg / kg.

[0062] The reaction liquid is successively subjected to desolventizing, dewatering, decoking, light component removal, and refining to obtain product bottom liquid at the bottom of the refining column, wherein the total content of THA and amide is 475 mg / kg, and the hexamethylene diamine product is obtained from the top of the column, with a polarographic value of 16 mmol IB / t-HMD.

[0063] Example 4

[0064] Into the reaction kettle are added 300 g of ethanol, 4 g of tetramethylammonium hydroxide pentahydrate, 40 g of Raney nickel catalyst (wet weight), 0.4 g of diatomite powder (pH = 7-8, average particle size 50 um, specific surface 92 m 2 / g, pore size 8.6 nm), adiponitrile, and product column mother liquor are fed at a space velocity of 4 g / g cat. / h, and hydrogen is introduced for hydrogenation reaction.

[0065] The reaction conditions are: 90°C, 3.3 MPa, the feeding amount is 200 g of adiponitrile and 10 g of product column mother liquor, after the feeding is completed, the reaction is stopped after being extended for 30 min, the reaction liquid composition is analyzed by sampling, and the solvent removal ratio, wherein the HMD content is 98.5 wt%, and the AMCPA content is 3 mg / kg.

[0066] The reaction liquid is successively subjected to desolventizing, dewatering, decoking, light component removal, and refining to obtain product bottom liquid at the bottom of the refining column, wherein the total content of THA and amide is 475 mg / kg, and the hexamethylene diamine product is obtained from the top of the column, with a polarographic value of 16 mmol IB / t-HMD.

[0067] Example 5

[0068] Into the reactor, 300 g of methanol, 1 g of NaOH, 10 g of Raney nickel catalyst (wet weight), 2 g of calcium carbonate powder (pH = 8-9, average particle size 25 um, specific surface 55 m 2 / g, pore size 50 nm), adiponitrile and light-removing mother liquor were fed at an empty speed of 5 g / g cat. / h, and hydrogen was introduced for hydrogenation reaction.

[0069] The reaction conditions were: 100°C, 1.5 MPa, the feeding amount was 200 g of adiponitrile and 2 g of light-removing mother liquor, after the feeding was completed, the reaction was stopped after being extended for 20 min, the reaction liquid composition was analyzed by sampling, and the solvent accounted for, wherein the HMD content was 98.8 wt%, and the AMCPA content was 2 mg / kg.

[0070] The reaction liquid was subjected to desolventization, dehydration, de-coking, light-removal and refining in sequence, the product bottom mother liquor was obtained at the bottom of the refining tower, wherein the total content of THA and amide was 465 mg / kg, the adiponitrile product was obtained at the top of the tower, and the polarographic value was 16 mmol IB / t-HMD.

[0071] Comparative Example 1

[0072] Referring to the method of Example 4, the difference is only that no adsorbent is added in the hydrogenation reaction, and other operations and conditions are unchanged. The reaction liquid composition is analyzed by sampling, and the solvent accounts for, wherein the HMD content is 96.3 wt%, and the AMCPA content is 20 mg / kg. The total content of THA and amide in the desolventization product tower bottom mother liquor is 992 mg / kg, and the polarographic value of the product obtained by rectification is 59 mmol IB / t-HMD.

[0073] Comparative Example 2

[0074] Referring to the method of Example 4, the difference is only that the recovered post-treatment mother liquor is not added in the reaction system, and other operations and conditions are unchanged.

[0075] The reaction liquid composition is analyzed by sampling, and the solvent accounts for, wherein the HMD content is 98.5 wt%, and the AMCPA content is 17 mg / kg. The total content of THA and amide in the desolventization product tower bottom mother liquor is 1257 mg / kg, and the polarographic value of the product obtained by rectification is 80 mmol IB / t-HMD.

[0076] Comparative Example 3

[0077] Referring to the method of Example 4, the difference is that no adsorbent and mother liquor are added, and other operations and conditions are unchanged.

[0078] The sample analysis reaction liquid composition, remove solvent proportion, wherein the HMD content is 98.5wt%, AMCPA content is 28mg / kg. The total content of THA and amide in the desolventized product tower bottom mother liquor is 1381mg / kg, and the product obtained by rectification has an extreme spectrum value of 95mmol IB / t-HMD.

[0079] Although the content of the present application has been described in detail by the above preferred embodiments, it should be recognized that the above description should not be considered as limiting the present application. Those skilled in the art can understand that some modifications or adjustments can be made to the present application under the teaching of the present specification. These modifications or adjustments should also be within the scope defined by the claims of the present application.

Claims

1. A process for the production of hexanediamine by hydrogenation of a nitrile, characterized in that, The reaction liquid is prepared by hydrogenation reaction of adiponitrile, and then prepared by post-treatment; wherein the hydrogenation reaction system further comprises an adsorbent and mother liquor produced in the post-treatment process; The mother liquor produced in the post-treatment process, wherein the mother liquor contains 10-5000 mg / kg of azepine Schiff base and 10-5000 mg / kg of amide; The adsorbent is selected from one or more of magnesium oxide, activated alumina, diatomite, calcium carbonate and activated carbon.

2. The method of claim 1, wherein, The mother liquor produced in the post-treatment process is added in an amount of 0.01-50 wt% of the amount of adiponitrile.

3. The method of claim 2, wherein, The mother liquor produced in the post-treatment process is added in an amount of 1-20 wt% of the amount of adiponitrile.

4. The method of claim 1, wherein, The pH value of the adsorbent is 7.0-14.

0.

5. The method of claim 4, wherein, The pH value of the adsorbent is 8-12.

6. The method of claim 1, wherein, The specific surface of the adsorbent is 50-500 m 2 / g.

7. The method of claim 6, wherein, The specific surface of the adsorbent is 100-300 m 2 / g.

8. The method of claim 1, wherein, The BET pore size of the adsorbent is 3-100 nm.

9. The method of claim 8, wherein, The BET pore size of the adsorbent is 5-20 nm.

10. The method of claim 1, wherein, The average particle size of the adsorbent is 10-1000 um.

11. The method of claim 10, wherein, The average particle size of the adsorbent is 20-80 um.

12. The method of claim 1, wherein, The adsorbent is added in an amount of 0.01-1 wt% of the amount of adiponitrile.

13. The method of claim 12, wherein, The adsorbent is added in an amount of 0.01-0.05 wt% of the amount of adiponitrile.

14. The method of claim 1, wherein, The hydrogenation reaction is carried out at a reaction temperature of 60-100 ℃ and a reaction pressure of 1.5-5 MPa.

15. The method of claim 14, wherein, The hydrogenation reaction is carried out at a reaction temperature of 65-85 ℃ and a reaction pressure of 2.0-3.5 MPa.

16. The method of claim 1, wherein, The feed space velocity is 0.5-5 g / g cat. / h based on the total amount of adiponitrile and the mother liquor produced in the post-treatment process.

17. The method of claim 16, wherein, The reaction is stopped after the feed is completed and the reaction is continued for 5-30 min.

18. The method of claim 1, wherein, The hydrogenation reaction system comprises a catalyst, and the catalyst is selected from one or more of skeletal nickel or skeletal cobalt catalysts.

19. The method of claim 18, wherein, The catalyst is a skeletal nickel catalyst.

20. The method of claim 18, wherein, The catalyst is added in an amount of 5-50 wt% of the amount of adiponitrile.

21. The method of claim 20, wherein, The catalyst is added in an amount of 15-30 wt% of the amount of adiponitrile.

22. The method of claim 1, wherein, The hydrogenation reaction system comprises a solvent, and the solvent is selected from one or more of methanol, ethanol, propanol, isopropanol and tetrahydrofuran.

23. The method of claim 22, wherein, The solvent is added in an amount of 0.2-5 times of the mass of adiponitrile.

24. The method of claim 1, wherein, The hydrogenation reaction system comprises an additive, and the additive is selected from one or more of NaOH, KOH, CsOH and tetramethylammonium hydroxide.

25. The method of claim 24, wherein, The additive is added in an amount of 0.1-5 wt% of the amount of adiponitrile.

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