A catalyst for synthesizing hexamethylenediamine and a preparation method thereof

Abstract

The present application provides a catalyst for synthesizing hexamethylenediamine, the catalyst comprising a carrier and ruthenium loaded on the carrier, the carrier being obtained by calcining a phenanthroline compound and a carrier matrix. The catalyst provided by the present invention has a good catalytic effect, and the catalyst is used for the reaction of synthesizing hexamethylenediamine by reductive amination of hexamethylenediol, the conversion rate of hexamethylenediamine is 100%, and the single-pass yield of hexamethylenediamine is significantly improved.

Description

Technical Field

[0001] The invention belongs to the field of chemical synthesis, and specifically relates to a catalyst for synthesizing hexamethylenediamine and a preparation method thereof. Background Art

[0002] Hexamethylenediamine, also known as 1,6-hexamethylenediamine and 1,6-diaminohexane, is an important chemical intermediate, which is widely used in the production of polyamides such as nylon 66, nylon 610, nylon 612 and nylon 69, hexamethylene diisocyanate, epoxy resin curing agent, organic crosslinking agent, etc. The common preparation processes of hexamethylenediamine mainly include: adiponitrile method, caprolactam method, adipaldehyde method or hexamethylenediol method, etc.

[0003] In industrial production, hexamethylenediamine is basically prepared by hydrogenation of adiponitrile. There are three main methods for producing adiponitrile: adipic acid catalytic amination method, acrylonitrile electrolytic dimerization method, and butadiene method. The adipic acid method is to produce adiponitrile by amination and dehydration of adipic acid and ammonia. Although the technology is mature, this method has high production cost, long process, more by-products, and low yield. The acrylonitrile electrolytic dimerization method is a method for preparing adiponitrile by direct electrolytic dimerization and hydrogenation of acrylonitrile in a medium. This process has the advantages of small unit product investment, unlimited construction scale, single raw material variety and relatively wide source, and relatively simple technology. However, the market price of its raw material acrylonitrile is high, and the power consumption is high. In addition, it uses highly toxic, highly corrosive and inconvenient to transport acrylonitrile raw materials, and its competitiveness is weak. Using butadiene as a raw material to produce adiponitrile through hydrocyanation reaction and then hydrogenating adiponitrile is the mainstream process for preparing hexamethylenediamine. This process produces adiponitrile and butadiene, which are widely available as raw materials with low energy consumption and cost. However, it has problems such as high technical difficulty, complex process route, and the raw material hydrogen cyanide being highly toxic and volatile.

[0004] The preparation of hexamethylenediamine by the caprolactam method is generally used in small-scale production equipment for processing caprolactam. It is a process in which caprolactam and ammonia react in the presence of a phosphate catalyst (such as a phosphate of manganese, aluminum, calcium, barium or zinc) to form aminocapronitrile in the gas phase; the generated aminocapronitrile is then hydrogenated to form hexamethylenediamine, a process similar to the hydrogenation of adiponitrile. The caprolactam method is only suitable for small-scale production, and the production cost is relatively high. The main problem of this method is the low yield and catalyst deactivation caused by the polymerization of caprolactam during the preparation of aminocapronitrile.

[0005] The adipaldehyde method uses benzene as raw material, partially hydrogenates benzene to cyclohexene, oxidizes cyclohexene to produce adipaldehyde, and reductively aminizes adipaldehyde to produce hexamethylenediamine. This method has a long process flow.

[0006] The hexanediol process is to prepare hexanediamine by ammoniation of 1,6-hexanediol (hexanediol for short). Hexanediol can be prepared by hydrogenation of adipic acid and its esters, and the method is mature; it can also be converted from biomass into 5-hydroxymethylfurfural, and further converted into hexanediol. The raw material source is wide and it is green and carbon-reducing. Therefore, the hexanediol process is a relatively ideal method for preparing hexanediamine. However, the hexanediol process has problems such as a large number of by-products and low single-pass yield. The selectivity of hexanediol to hexanediamine can be improved by recycling the by-products aminohexanol, cyclohexaneimine, dimers and trimers, but the low single-pass yield will lead to the separation of a large number of by-products in the circulation process and high circulation energy consumption. Therefore, the development of catalysts with high selectivity and high yield has become a key issue of this technology.

[0007] The literature Science China Chemsitry 2017, 60, 920–926. reports a metal ruthenium-based catalyst for the reductive amination of hexanediol to prepare hexamethylenediamine. The conversion rate of hexamethylenediol is 100%, the selectivity of hexamethylenediamine is 38.4%, and the single-pass yield of hexamethylenediamine is 38.4%. This method saves costs and has a high conversion rate, but its single-pass yield is low and needs to be improved. Summary of the invention

[0008] In view of this, an object of the present invention is to provide a catalyst for preparing hexamethylenediamine by reductive amination of hexamethylenediol, wherein the catalyst can improve the single-pass yield of hexamethylenediamine.

[0009] To achieve the above object, the technical solution of the present invention is:

[0010] The present invention provides a catalyst for synthesizing hexamethylenediamine, comprising:

[0011] A carrier and ruthenium supported on the carrier;

[0012] The carrier is obtained by calcining a phenanthroline compound and a carrier matrix.

[0013] Preferably, the phenanthroline compound is selected from one or more of 1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, 2,9-dibromo-1,10-phenanthroline and 4,7-dihydroxy-1,10-phenanthroline.

[0014] Preferably, the molar ratio of the phenanthroline compound to ruthenium is 0.5 to 4, and the loading amount of ruthenium in the catalyst is 1 wt% to 5 wt%.

[0015] In some possible implementations, the carrier matrix is ​​selected from one or more of Al2O3, TiO2, SiO2 and diatomaceous earth.

[0016] The present invention also provides a method for preparing the above catalyst, comprising the following steps:

[0017] The ruthenium salt is loaded onto a carrier, and then subjected to first calcination and reduction in sequence to obtain a catalyst;

[0018] The carrier is obtained by the second calcination of a phenanthroline compound and a carrier matrix.

[0019] Preferably, the molar ratio of the phenanthroline compound to the ruthenium salt is 0.5 to 4, and the loading amount of ruthenium in the catalyst is 1 wt% to 5 wt%.

[0020] In some possible implementations, the temperature of the first calcination is 300° C. to 500° C., and the time of the first calcination is 1 h to 3 h.

[0021] In some possible implementations, the temperature of the second calcination is 600° C. to 900° C., and the time of the second calcination is 1 h to 3 h.

[0022] Preferably, the reduction is carried out in a hydrogen atmosphere.

[0023] The present invention provides a method for preparing hexamethylenediamine, comprising:

[0024] Hexanediol is subjected to reductive amination in a hydrogen and ammonia atmosphere under the action of the above catalyst to obtain hexamethylenediamine.

[0025] Compared with the prior art, the present invention provides a catalyst for synthesizing hexamethylenediamine, the catalyst comprising a carrier and ruthenium loaded on the carrier, the carrier being obtained by calcining a phenanthroline compound and a carrier matrix. The catalyst provided by the present invention has a good catalytic effect, and the catalyst is used for the reaction of synthesizing hexamethylenediamine by reductive amination of hexamethylenediol, the conversion rate of hexamethylenediamine is 100%, and the single-pass yield of hexamethylenediamine is significantly improved. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The invention provides a catalyst for synthesizing hexamethylenediamine, comprising a carrier and ruthenium loaded on the carrier, wherein the carrier is obtained by calcining a phenanthroline compound and a carrier matrix.

[0028] Specifically, the carrier matrix is ​​selected from one or more of Al2O3, TiO2, SiO2 and diatomaceous earth, preferably Al2O3, more preferably activated Al2O3, and the activation is preferably calcined in air at 800°C; the phenanthroline compound is selected from one or more of 1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, 2,9-dibromo-1,10-phenanthroline and 4,7-dihydroxy-1,10-phenanthroline, preferably 1,10-phenanthroline, 4,7-dimethyl- 1,10-phenanthroline or 2,9-dibromo-1,10-phenanthroline; the molar ratio of the phenanthroline compound to ruthenium is 0.5-4, preferably 0.5, 1 or 2; in some possible implementations, the phenanthroline compound is impregnated onto a carrier substrate, dried at 80°C-120°C, preferably at 100°C, the drying time is 7h-9h, preferably 8h, and a second calcination is performed after drying, the second calcination temperature is 600°C-900°C, preferably 700°C or 800°C, the second calcination time is 1h-3h, preferably 2h, and the carrier is obtained after the second calcination.

[0029] The catalyst is obtained by loading ruthenium onto the carrier. The loading amount of ruthenium in the catalyst is 1wt% to 5wt%, preferably 3wt%; in some possible implementations, the catalyst is obtained by impregnating the carrier with a ruthenium salt, drying, calcining and reducing the carrier. The ruthenium salt is selected from one or more of ruthenium acetate, hydrated ruthenium chloride, ruthenium nitrate, ammonium chlororuthenate and (1,5-cyclooctadiene) ruthenium chloride, preferably hydrated ruthenium chloride or ruthenium nitrate; after the ruthenium salt is impregnated on the carrier, it is dried, the drying temperature is 80°C to 120°C, preferably 100°C, and the drying time is 7h to 9h, preferably 8h; after drying, a first calcination is performed, the temperature of the first calcination is 300°C to 500°C, preferably 400°C, and the time of the first calcination is 1h to 3h, preferably 2h; after the first calcination, a reduction reaction is performed under a hydrogen atmosphere. In some specific embodiments, hydrogen is used for reduction, the temperature of the reduction reaction is 200°C to 300°C, preferably 250°C, and the time of the reduction reaction is 1h to 3h, preferably 2h, and the catalyst is obtained after reduction.

[0030] The present invention also provides a method for preparing the above-mentioned catalyst, comprising the following steps: loading a ruthenium salt on a carrier, and sequentially subjecting the carrier to a first calcination and a reduction to obtain a catalyst, wherein the carrier is obtained by a second calcination of a phenanthroline compound and a carrier matrix, and the specific preparation method is as described above.

[0031] The present invention provides a method for preparing hexamethylenediamine, comprising: subjecting hexamethylenediol to a reduction amination reaction in a hydrogen and ammonia atmosphere under the action of the above catalyst to obtain hexamethylenediamine. In some possible implementations, the preparation method further comprises tert-butyl alcohol.

[0032] Specifically, the reductive amination reaction is carried out in an autoclave, hexylene glycol, tert-butyl alcohol and a catalyst are added to the autoclave, the amount of hexylene glycol and the catalyst is 3-6 mmol (0.35-0.71 g): 0.08-0.12 g, preferably 5 mmol (0.59 g): 0.1 g; the amount of tert-butyl alcohol and the catalyst is 3-6 mL: 0.08-0.12 g, preferably 5 mL: 0.1 g; the autoclave is sealed, the gas space in the autoclave is purged with nitrogen first, and then the gas space in the autoclave is purged with hydrogen, so that The pressure of hydrogen in the autoclave is 1.0-3.0 MPa, preferably 1.0 MPa or 2.0 MPa; the autoclave is heated to a temperature of 180°C-240°C, preferably 220°C or 190°C, and then ammonia is pumped in, and the pressure of ammonia is 10 MPa-14 MPa, preferably 11 MPa or 13 MPa; the reductive amination reaction is preferably carried out under stirring, the reaction temperature is 180°C-240°C, preferably 220°C or 190°C, the reaction time is 20h-28h, preferably 24h, and a reactant containing hexamethylenediamine is obtained after the reaction.

[0033] The invention provides a catalyst for synthesizing hexamethylenediamine, the catalyst comprising a carrier and ruthenium loaded on the carrier, wherein the carrier is obtained by calcining a phenanthroline compound and a carrier matrix. The catalyst provided by the invention has a good catalytic effect, and the catalyst is used for the reaction of synthesizing hexamethylenediamine by reductive amination of hexamethylenediol, the conversion rate of hexamethylenediamine is 100%, and the single-pass yield of hexamethylenediamine is significantly improved.

[0034] Embodiment 1:

[0035] The activated Al2O3 treated by calcination in air at 800°C is used as a carrier matrix, the phenanthroline compound is 1,10-phenanthroline, the ruthenium salt is hydrated ruthenium chloride, the ruthenium loading is 3wt%, and the molar ratio of 1,10-phenanthroline to hydrated ruthenium chloride is 1. First, 1,10-phenanthroline is impregnated on the carrier, dried at 100°C for 8h, and calcined at high temperature at 800°C for 2h to obtain the carrier; then, hydrated ruthenium chloride is impregnated on the surface of the carrier, dried at 100°C for 8h, calcined at 400°C for 2h, and reduced with hydrogen at 250°C for 2h to obtain the catalyst.

[0036] The catalyst obtained above is used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst is determined. The reaction is carried out in a 100ml autoclave, 5mmol (0.59g) hexamethylenediol, 5mL tert-butyl alcohol and 0.1g catalyst are added to the autoclave, the reactor is sealed, and the gas space is purged with nitrogen and hydrogen in turn to stabilize the hydrogen pressure of the final reaction system at 1MPa, and after heating to 220°C, 13MPa ammonia is pumped in, mechanical stirring is turned on to start the reaction, and after 24h of reaction, stirring is stopped to end the reaction. The autoclave is cooled to room temperature, the pressure is released, the mixture obtained by the reaction is filtered, and the mixture is analyzed by gas chromatography, and the conversion rate and yield are calculated based on the molar content of each component in the mixture. The test analysis results are as follows: the conversion rate of hexanediol is 100%, the yield of hexamethylenediamine is 54%, and the following by-products are contained: cyclohexylimine, 6-amino-1-hexanol, hexylamine, hexanol, and dimer (the dimer is N-(6-aminohexyl)-1,6-hexamethylenediamine and N-(6-aminohexyl)cyclohexylimine).

[0037] Embodiment 2:

[0038] The activated Al2O3 treated by calcination in air at 800°C is used as a carrier matrix, the phenanthroline compound is 1,10-phenanthroline, the ruthenium salt is hydrated ruthenium chloride, the ruthenium loading is 3wt%, and the molar ratio of 1,10-phenanthroline to hydrated ruthenium chloride is 1. First, 1,10-phenanthroline is impregnated on the carrier, dried at 100°C for 8h, and calcined at 700°C for 2h to obtain the carrier; then, hydrated ruthenium chloride is impregnated on the surface of the carrier, dried at 100°C for 8h, calcined at 400°C for 2h, and reduced with hydrogen at 250°C for 2h to obtain the catalyst.

[0039] The catalyst obtained above was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The reaction process and analysis method were the same as those in Example 1. The test analysis results were: the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 49%.

[0040] Embodiment 3:

[0041] The activated Al2O3 treated by calcination in air at 800°C is used as a carrier matrix, the phenanthroline compound is 1,10-phenanthroline, the ruthenium salt is hydrated ruthenium chloride, the ruthenium loading is 3wt%, and the molar ratio of 1,10-phenanthroline to hydrated ruthenium chloride is 2. First, 1,10-phenanthroline is impregnated on the carrier, dried at 100°C for 8h, and calcined at high temperature at 800°C for 2h to obtain the carrier; then, hydrated ruthenium chloride is impregnated on the surface of the carrier, dried at 100°C for 8h, calcined at 400°C for 2h, and reduced with hydrogen at 250°C for 2h to obtain the catalyst.

[0042] The catalyst obtained above was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The reaction process and analysis method were the same as those in Example 1. The test analysis results were: the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 48%.

[0043] Embodiment 4:

[0044] The activated Al2O3 treated by calcination in air at 800°C is used as a carrier matrix, the phenanthroline compound is 1,10-phenanthroline, the ruthenium salt is hydrated ruthenium chloride, the ruthenium loading is 3wt%, and the molar ratio of 1,10-phenanthroline to hydrated ruthenium chloride is 0.5. First, 1,10-phenanthroline is impregnated on the carrier, dried at 100°C for 8h, and calcined at 800°C for 2h to obtain the carrier; then, hydrated ruthenium chloride is impregnated on the surface of the carrier, dried at 100°C for 8h, calcined at 400°C for 2h, and reduced with hydrogen at 250°C for 2h to obtain the catalyst.

[0045] The catalyst obtained above was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The reaction process and analysis method were the same as those in Example 1. The test analysis results were: the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 46%.

[0046] Embodiment 5:

[0047] The activated Al2O3 treated by calcination in air at 800°C is used as a carrier matrix, the phenanthroline compound is 4,7-dimethyl-1,10-phenanthroline, the ruthenium salt is hydrated ruthenium chloride, the ruthenium loading is 3wt%, and the molar ratio of 4,7-dimethyl-1,10-phenanthroline to hydrated ruthenium chloride is 1. First, 4,7-dimethyl-1,10-phenanthroline is impregnated on the carrier, dried at 100°C for 8h, and calcined at high temperature at 800°C for 2h to obtain the carrier; then, hydrated ruthenium chloride is impregnated on the surface of the carrier, dried at 100°C for 8h, calcined at 400°C for 2h, and reduced with hydrogen at 250°C for 2h to obtain the catalyst.

[0048] The catalyst obtained above was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The reaction process and analysis method were the same as those in Example 1. The test analysis results were: the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 52%.

[0049] Embodiment 6:

[0050] The activated Al2O3 treated by calcination in air at 800°C is used as a carrier matrix, the phenanthroline compound is 2,9-dibromo-1,10-phenanthroline, the ruthenium salt is hydrated ruthenium chloride, the ruthenium loading is 3wt%, and the molar ratio of 2,9-dibromo-1,10-phenanthroline to hydrated ruthenium chloride is 1. First, 2,9-dibromo-1,10-phenanthroline is impregnated on the carrier, dried at 100°C for 8h, and calcined at 800°C for 2h to obtain the carrier; then, hydrated ruthenium chloride is impregnated on the surface of the carrier, dried at 100°C for 8h, calcined at 400°C for 2h, and reduced with hydrogen at 250°C for 2h to obtain the catalyst.

[0051] The catalyst obtained above was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The reaction process and analysis method were the same as those in Example 1. The test analysis results were: the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 50%.

[0052] Embodiment 7:

[0053] The catalyst obtained in Example 1 was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The hydrogen pressure was 2 MPa, and the other conditions were the same as in Example 1. The test analysis results showed that the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 51%.

[0054] Embodiment 8:

[0055] The catalyst obtained in Example 1 was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The ammonia pressure was 11 MPa, and the other conditions were the same as in Example 1. The test analysis results showed that the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 49%.

[0056] Embodiment 9:

[0057] The catalyst obtained in Example 1 was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The reaction temperature was 190° C., and other conditions were the same as in Example 1. The test analysis results showed that the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 45%.

[0058] Embodiment 10:

[0059] Active Al2O3 is used as a carrier matrix, the phenanthroline compound is 1,10-phenanthroline, the ruthenium salt is ruthenium nitrate, the ruthenium loading is 3wt%, and the molar ratio of 1,10-phenanthroline to hydrated ruthenium chloride is 1. First, 1,10-phenanthroline is impregnated on the carrier, dried at 100°C for 8h, and calcined at 800°C for 2h to obtain the carrier; then, hydrated ruthenium chloride is impregnated on the surface of the carrier, dried at 100°C for 8h, calcined at 400°C for 2h, and reduced with hydrogen at 250°C for 2h to obtain the catalyst.

[0060] The catalyst obtained above was used for the reaction of preparing hexamethylenediamine by reductive amination of hexamethylenediol, and the catalytic performance of the catalyst was measured. The reaction process and analysis method were the same as those in Example 1. The test analysis results were: the conversion rate of hexamethylenediol was 100%, and the yield of hexamethylenediamine was 53%.

[0061] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A catalyst for synthesizing hexamethylenediamine, characterized in that: include: A carrier and ruthenium supported on the carrier; The carrier is obtained by calcining a phenanthroline compound and a carrier matrix; The carrier matrix is ​​selected from Al2O3; The calcination temperature is 600°C to 900°C, and the calcination time is 1 h to 3 h; The molar ratio of the phenanthroline compound to ruthenium is 0.5-4, and the loading amount of ruthenium in the catalyst is 1 wt%-5wt%.

2. The catalyst according to claim 1, characterized in that The phenanthroline compound is selected from one or more of 1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, 2,9-dibromo-1,10-phenanthroline and 4,7-dihydroxy-1,10-phenanthroline.

3. A method for preparing the catalyst according to claim 1 or 2, characterized in that: The following steps are involved: The ruthenium salt is loaded onto a carrier, and then subjected to first calcination and reduction in sequence to obtain a catalyst; The carrier is obtained by a second calcination of a phenanthroline compound and a carrier matrix; The molar ratio of the phenanthroline compound to the ruthenium salt is 0.5-4, and the loading amount of ruthenium in the catalyst is 1 wt%-5wt%.

4. The preparation method according to claim 3, characterized in that: The temperature of the first calcination is 300° C. to 500° C., and the time of the first calcination is 1 h to 3 h.

5. The preparation method according to claim 3, characterized in that: The temperature of the second calcination is 600° C. to 900° C., and the time of the second calcination is 1 h to 3 h.

6. The preparation method according to claim 3, characterized in that: The reduction is carried out in a hydrogen atmosphere.

7. A method for preparing hexamethylenediamine, characterized in that: include: Hexanediol is subjected to reductive amination in a hydrogen and ammonia atmosphere under the action of the catalyst described in claim 1 or 2 to obtain hexamethylenediamine.