Production method of n-hexylamine and supported catalyst used in production method

Abstract

The invention belongs to the field of chemical engineering, and relates to a production method for preparing n-hexylamine by using a high-performance catalyst with Al2O3 as a carrier. The invention provides a supported catalyst. The supported catalyst is composed of a catalyst carrier and cobalt, copper, zinc and molybdenum which serve as active components. The invention also provides a method for preparing n-hexylamine by taking n-hexanol as a raw material, and n-hexanol, liquid ammonia and hydrogen are subjected to amination reaction on a catalyst bed layer by using the supported catalyst. The preparation method of the n-hexylamine is free of an external hydrogen source and depends on hydrogen transfer in the catalyst; all atoms in reactants enter a product or byproduct water, and the atom utilization rate is close to 100%; the byproduct is only water, toxic waste is avoided, and the method has the characteristics of clean and environment-friendly process and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of chemical industry and relates to a production method for preparing high-performance catalyst for preparing n-hexylamine with Al2O3 as a carrier. BACKGROUND

[0002] As an important organic synthesis intermediate, n-hexylamine plays a key role in many fields due to its unique chemical properties and wide application prospects. In the pharmaceutical field, it is an important raw material for synthesizing various drug intermediates, which can be used to prepare antiarrhythmic drugs, antibiotics, etc.; in the pesticide industry, as a key additive, it can effectively improve the penetration, dispersion and adhesion performance of pesticides, enhance the pesticide efficacy and help the prevention and control of crop diseases and pests; in the rubber processing industry, n-hexylamine can be used as a raw material for accelerators and antioxidants to improve the vulcanization speed and anti-aging performance of rubber products and prolong the service life of rubber products; in addition, in the surfactant, dye and coating industries, n-hexylamine also plays an indispensable role and is a key raw material in the production process of many fine chemicals.

[0003] At present, the preparation methods of n-hexylamine mainly include n-hexanol catalytic amination method, n-hexyl cyanide reduction method, brominated n-hexane ammonolysis reaction and caprolactam method, among which the n-hexanol amination method has realized industrialization due to the advantages of easy availability of raw materials, mature process and outstanding economy. This method uses n-hexanol and ammonia as raw materials to synthesize n-hexylamine under the action of catalyst at high temperature and high pressure. However, due to the limitation of catalyst technology, there are great differences in production technology at home and abroad, and the product quality is uneven.

[0004] The existing preparation method of n-hexylamine includes the following: 1) CN114539071A: The catalyst is composed of active components, additives and carriers, wherein the active components are nickel metal, the additives are cerium elements, and the carriers are γ-alumina. The mixed gas of gaseous n-hexanol, ammonia and hydrogen is introduced into a fixed bed reactor loaded with alumina-supported bimetallic nickel-cerium catalyst, and reduction amination reaction is carried out at 150-230℃ to obtain n-hexylamine; the highest conversion rate of raw material n-hexanol is only 91%, the product selectivity of n-hexylamine is 21%, the by-product is n-hexyl cyanide, and the selectivity of n-hexyl cyanide reaches 76%.

[0005] 2)、CN110302790A discloses a process method, which first carries out amination reaction of ammonia and caprolactam in a first reactor to obtain an amination liquid, then pours the amination liquid into a second reactor, adds a catalyst and a solvent to carry out hydrogenation reaction, and obtains product hexamethylene diamine, n-hexylamine and cyclohexyl imine. The process synthesis reaction step is complex and cumbersome, the temperature of amination reaction is 300℃~500℃, the reaction temperature is high, the service life of the equipment will be shortened and there is a high temperature safety risk; the catalyst is Co-Zn / Al2O3, which contains the following components by weight: Co is 0~30.0%, Zn is 0~25.0%, and the rest is Al2O3.

[0006] 3)、CN113968788A discloses a production process of n-hexylamine, which contains methyl n-hexyl ketone oxime, diethyl ether, phosphorus pentachloride, catalyst, n-hexanol, ammonia, hydrogen, caprolactam, sodium carbonate, organic solvent and the like. Through multi-step reaction, intermediate products such as N-acyl n-hexylamine are first obtained, and then n-hexylamine is obtained through extraction, distillation and other operations. The reaction condition of the process is high in reaction temperature, the variety of raw materials is large, the number of side reactions increases, and then a solvent is added, a new substance exists, which increases the difficulty of separation. At the same time, the existence of carbonate is not friendly to the environment.

[0007] 4)、CN102639231A discloses a catalyst and method for preparing amine, which comprises reacting a primary alcohol or a secondary alcohol, an aldehyde and / or a ketone with hydrogen and a nitrogen compound selected from ammonia, a primary amine and a secondary amine in the presence of a supported catalyst containing copper, nickel and cobalt, wherein the catalytically active substances of the catalyst comprise an aluminum oxide compound, a copper oxide compound, a nickel oxide compound and a cobalt oxide compound and 0.2-5.0% by weight of a tin oxide compound calculated as SnO before they are reduced with hydrogen. The catalyst can be used for the preparation of n-hexylamine, but the raw material conversion rate and product selectivity are not given. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a production method of n-hexylamine and a used supported catalyst.

[0009] In order to solve the above problems, the present application provides a supported catalyst, characterized in that the supported catalyst is composed of a catalyst carrier and cobalt, copper, zinc and molybdenum as active components. The loading amount of cobalt is 8~16wt%, the loading amount of copper is 3~9wt%, the loading amount of zinc is 3~6wt%, and the loading amount of molybdenum is 0~2wt%.

[0010] As an improvement of the supported catalyst of the present application: the loading amount of cobalt is 13.5~15.0wt %, the loading amount of copper is 3.5~5.0 wt %, the loading amount of zinc is 3.5~4.2wt %, and the loading amount of molybdenum is 0.8~1.5 wt %.

[0011] As a further improvement of the supported catalyst of the present application: the loading amount of cobalt is 15.0wt %, the loading amount of copper is 3.5wt %, the loading amount of zinc is 4.2wt %, and the loading amount of molybdenum is 0.8wt %.

[0012] The present application also simultaneously provides a preparation method of the above-mentioned supported catalyst, comprising the following steps: ①, preparation of catalyst carrier Add water (deionized water) and acid (including nitric acid, sulfuric acid, etc.) to pseudo-boehmite and sesbania powder, mix uniformly, extrude (use extruder), dry, first heat to 300±30℃, calcine for 2±0.1 hours, then heat to 400~500℃ and calcine for 10±0.5 hours, to obtain the catalyst carrier; The mass ratio of pseudo-boehmite:sesbania powder is 100:4.5~5.5; ②, according to the above-mentioned loading amount of cobalt, copper, zinc and molybdenum, add cobalt nitrate, copper nitrate, zinc nitrate and molybdenum nitrate into water to prepare a mixed nitrate solution; Put the catalyst carrier into the mixed nitrate solution for impregnation, then dry, and calcine at 450±50℃ for 5±0.5h to obtain the supported catalyst carrier; The mixed nitrate solution needs to be fully absorbed by the catalyst carrier; ③, activation and reduction of the catalyst: Activate and reduce the supported catalyst carrier in a hydrogen atmosphere (hydrogen pressure 0.05MPa), the reduction temperature is 400~500℃, until no water is produced; obtain the supported catalyst (cobalt-copper-zinc-molybdenum supported catalyst).

[0013] Note: the reduction step can be directly carried out in the reactor.

[0014] As an improvement of the preparation method of the supported catalyst of the present application: In step ①: the weight ratio of pseudo-boehmite:water (deionized water):nitric acid is 1:1.4~1.6:0.04~0.06; In step ②: use the method of twice impregnation-drying-calcination; the impregnation time of each time is 1.5±0.5 hours.

[0015] As a further improvement of the preparation method of the supported catalyst of the present application: The drying of step ① is drying at 120±20℃ for 3±0.5h. The drying of step ② is drying at 120±20℃ for 3±0.5h.

[0016] Further improvement of the preparation method of the supported catalyst of the present application: In step ③, the space velocity is 10h -1 ; the reduction temperature is 450℃.

[0017] The present application also provides a method for preparing n-hexylamine using n-hexanol as raw material, which utilizes the above supported catalyst and comprises the following steps: 1) A supported catalyst (activated and reduced cobalt-copper-zinc-molybdenum supported catalyst) is arranged in the reactor as a catalyst bed, n-hexanol, liquid ammonia and hydrogen are fed into a vaporizer after being heated and vaporized, and then enter the reactor to undergo amination reaction in the catalyst bed; the reaction temperature is 140-250℃ (preferably 140-180℃, more preferably 160-180℃); the reaction pressure is 0.2-1.5Mpa (preferably 0.8-1.3Mpa), and the reaction space velocity is 0.1-0.5h -1 (preferably 0.25-0.5h -1 ); Explanation: The raw material n-hexanol is pressurized by a horizontal flow pump, and then enters the vaporizer together with liquid ammonia from a double-plunger pump metering pump and hydrogen from a steel cylinder, so that the above feeding ratio is controlled by the n-hexanol metering pump, the liquid ammonia metering pump and the hydrogen flow meter; The outlet of the reactor is connected to a crude product tank, which is provided with a vent line at the top, the vent line is connected to a water absorption system, and a vent valve and a back pressure valve are respectively arranged on the vent line, and the back pressure valve is used to adjust the reaction pressure in the reactor; that is, the system pressure is adjusted and controlled by the back pressure valve on the vent line. The reaction space velocity is the amount of n-hexanol passing through a unit of catalyst per unit time, that is, the reaction space velocity = n-hexanol volume feed rate / supported catalyst volume; 2) The crude product after reaction is cooled naturally to form a liquid phase and a gas phase, and the liquid phase contains n-hexylamine as the product.

[0018] Improvement of the method for preparing n-hexylamine using n-hexanol as raw material of the present application: The liquid phase enters the crude product tank, and the gas phase is discharged through the top pipeline of the crude product tank to the water absorption system.

[0019] Further improvement of the method for preparing n-hexylamine using n-hexanol as raw material of the present application: The n-hexyl amine includes n-hexyl amine, di-n-hexyl amine and tri-n-hexyl amine, and the n-hexyl amine is taken as a main product.

[0020] The conversion rate of the n-hexyl alcohol can be up to 96.8% or more, and the total selectivity of the n-hexyl amine, di-n-hexyl amine and tri-n-hexyl amine can be up to 97.5% or more by using the internal standard analysis method of the gas chromatography.

[0021] The conversion rate of the n-hexyl alcohol = (total n-hexyl alcohol concentration - residual n-hexyl alcohol concentration) / total n-hexyl alcohol concentration * 100%; The total selectivity of the n-hexyl amine, di-n-hexyl amine and tri-n-hexyl amine = (n-hexyl amine concentration + di-n-hexyl amine concentration + tri-n-hexyl amine concentration) / total n-hexyl alcohol concentration - residual n-hexyl alcohol concentration * 100%.

[0022] Therefore, the present application develops a method for preparing n-hexyl amine by using Mo as a catalytic additive, Co, Cu and Zn elements as active components and Al2O3 as a carrier.

[0023] The beneficial effects of the present application mainly include: 1. The novel catalyst prepared by using Mo as a catalytic additive, Co, Cu and Zn as active components and Al2O3 as a carrier has the characteristics of strong catalytic activity, good stability and long service life, which helps to maintain the structure and performance of the catalyst, makes it more stable in the reaction process and is not easy to be deactivated.

[0024] 2. The catalyst provided by the present application is used to prepare n-hexyl amine, the reaction condition is mild, the conversion rate of n-hexyl alcohol is up to 96.8% or more, the total selectivity of n-hexyl amine (n-hexyl amine), di-n-hexyl amine and tri-n-hexyl amine is more than 97.5%, the selectivity of n-hexyl amine is 81.5%, the product quality is good, and the production cost is low.

[0025] 3. The preparation method of n-hexyl amine provided by the present application can randomly adjust the product ratio of n-hexyl amine, di-n-hexyl amine and tri-n-hexyl amine according to market demand, and does not affect the catalyst activity, stability and service life.

[0026] 4. The preparation method of n-hexyl amine provided by the present application does not need external hydrogen source, depends on hydrogen transfer in the catalyst; all atoms in the reactant enter the product (n-hexyl amine) or byproduct water, the atom utilization rate is close to 100%; the byproduct is only water, there is no toxic waste, and the process has the characteristics of clean and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0027] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0028] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings.Figure 1 is a schematic diagram of a reaction device. DETAILED DESCRIPTION

[0029] The application will be further described in conjunction with specific examples, but the scope of protection of the application is not limited thereto.

[0030] Catalyst Example 1: 1), 100g of pseudo-boehmite and 5g of sesbania powder were uniformly mixed, then 150g of deionized water was weighed, 5g of nitric acid was added to the water, and the mixture was uniformly mixed, then the mixture was extruded into a columnar body with a diameter of 4mm and a length of 3-8mm using an extruder, then the columnar body was dried at 110℃ for 3h, then the temperature was raised to 280℃ in a muffle furnace, and the columnar body was calcined for 2h, then the temperature was raised to 400℃, and the columnar body was calcined for 10h to obtain a catalyst carrier.

[0031] 2), the active components of the catalyst were set as follows: Co 15.0Wt%, Cu 3.5Wt%, Zn 4.2Wt%, Mo 0.8Wt%, and the balance was the catalyst carrier.

[0032] According to the above-mentioned proportioning relationship of the active components, a nitrate mixed solution composed of cobalt nitrate, copper nitrate, zinc nitrate, molybdenum nitrate and water was prepared; the amount of water must ensure that the above-mentioned nitrates can be dissolved, and that the nitrate mixed solution can be completely absorbed by the catalyst carrier (which can be determined according to the water absorption rate of the catalyst carrier).

[0033] The nitrate mixed solution was poured into the catalyst carrier obtained in step 1) for impregnation, and two times of impregnation, drying and calcination were adopted, and each time of impregnation-drying-calcination was as follows: impregnation time 1.5h, then the impregnated catalyst was air-dried (air-dried until no water droplets were formed), placed in a 110℃ oven for drying for 3h, and calcined at 450℃ for 5h; the second time of impregnation-drying-calcination was the same as the first time of impregnation-drying-calcination, to obtain a supported catalyst carrier. Through calcination, cobalt nitrate, copper nitrate, zinc nitrate and molybdenum nitrate were all converted into corresponding metal oxides, so that the metal oxides were attached to the supported catalyst.

[0034] 3), about 100ml of the supported catalyst carrier obtained in step 2) was packed in a reactor with an inner diameter of 45cm and a height of 120cm for hydrogen reduction; the catalyst was packed as follows: a layer of 28cm porcelain balls was laid at the bottom of the reactor, and then 100ml of the catalyst was poured into the porcelain balls after the porcelain balls were laid flat, and then another layer of 28cm porcelain balls was laid; the reduction conditions were as follows: reduction temperature rising rate 8-10℃ / min, hydrogen pressure 0.05MPa, temperature 450℃, space velocity 10h -1 Under the above conditions, until no water was produced, a supported metal catalyst cat.1 was obtained.

[0035] Note: Space velocity = hydrogen gas flow rate (standard conditions) / catalyst volume; Metal oxides are reduced with hydrogen at high temperatures to form the corresponding metals.

[0036] Catalyst Example 2, compared to Catalyst Example 1, is modified as follows: 1) Replace “5g nitric acid” with “5g sulfuric acid”, which is equivalent to step 1 of catalyst example 1.

[0037] 2) Set cobalt to 13.5 wt%, copper to 5.0 wt%, zinc to 3.5 wt%, and molybdenum to 1.5 wt%, with the remainder being the same as step 2 of catalyst example 1.

[0038] 3) Equivalent to step 3 of catalyst example 1.

[0039] The supported catalyst cat.2 was obtained.

[0040] Catalyst Example 3, compared to Catalyst Example 1, is modified as follows: The composition was set as follows: cobalt 10.3 wt%, copper 7.5 wt%, zinc 5.5 wt%, and molybdenum 0.2 wt%, with the remainder being the same as catalyst example 1. This yielded the supported catalyst cat.3.

[0041] The method for preparing n-hexylamine from n-hexanol according to the present invention is as follows (using, for example...) Figure 1 The conventional apparatus described above consists of a reactor filled with a catalyst bed. Hexanol, the raw material, is metered and pressurized by a hexanol metering pump (using a horizontal flow pump, referred to as the hexanol pump), and then enters the vaporizer along with liquid ammonia from a liquid ammonia metering pump (using a double-plunger metering pump, referred to as the ammonia pump) and hydrogen from a gas cylinder. After being heated to 140-250°C and vaporized, it enters the reactor, where an amination reaction occurs in the catalyst bed. Therefore, the feed ratio is controlled by the hexanol metering pump, the liquid ammonia metering pump, and the hydrogen flow meter. The products obtained from the amination reaction are cooled by a condenser, forming liquid and gaseous products that enter a crude product tank (crude amine tank). The top of the crude product tank is equipped with a conventional vent line connected to a water absorption system. The vent line is equipped with a vent valve and a back pressure valve, the latter used to regulate the reaction pressure within the reactor. The uncondensed gas (i.e., the gaseous product) after gas-liquid condensation is discharged through the vent valve. Another function of the vent valve is to release pressure in case of abnormal pressure. The gaseous products mainly consist of the following components: liquid ammonia, methane, and hydrogen. After entering the water absorption system, the liquid ammonia forms an alkaline solution, while the other components that are insoluble in water (methane and hydrogen) are released into the atmosphere.

[0042] The crude product (liquid phase product) includes n-hexylamine, di-n-hexylamine, tri-n-hexylamine, n-hexanol, liquid ammonia and water and the like, and can be subjected to the following conventional post-treatment: a small amount of liquid ammonia is removed by an ammonia tower (the ammonia tower top temperature is 20-50 DEG C), n-hexylamine product is collected by an atmospheric distillation tower at 130-135 DEG C, di-n-hexylamine product is collected by a vacuum distillation tower (-0.095 MPa) at 85-95 DEG C, and tri-n-hexylamine is collected by a vacuum distillation tower (-0.095 MPa) at 160-170 DEG C, so that n-hexylamine (purity > 99.5%), di-n-hexylamine (purity > 99.5%) and tri-n-hexylamine (purity > 98.5%) can be obtained by distillation.

[0043] Specifically, see the following examples.

[0044] Example 1: a supported metal catalyst cat.1 prepared in catalyst example 1 is filled in a reactor at 100 ml, raw materials ammonia, hydrogen and n-hexanol are put into a vaporizer at a molar ratio of 3:3:1, and then the mixture is heated and vaporized (about 160 DEG C) and enters the reactor, and the amination reaction is carried out at a temperature of 180 DEG C, a pressure of 1.0 MPa and a space velocity of 0.25 h -1 The amination reaction is carried out at a space velocity of 0.25 h

[0045] The liquid phase product and the gas phase product formed after the amination reaction are cooled by condensation and enter a crude product tank, the liquid phase product is stored in the crude product tank (which can be separated according to the above method subsequently), and the gas phase product is discharged to a water absorption system through a vent line at the top of the crude product tank.

[0046] The liquid phase product is a crude n-hexylamine product, and the total conversion rate of n-hexanol is 96.8% by gas chromatography analysis, wherein the selectivity of n-hexylamine is 81.8%, the selectivity of di-n-hexylamine is 12.4%, and the selectivity of tri-n-hexylamine is 3.3%.

[0047] Example 2: a supported metal catalyst cat.2 prepared in catalyst example 2 is filled in a reactor at 100 ml, and the rest is the same as example 1. The total conversion rate of n-hexanol is 93.1% by gas chromatography analysis, wherein the selectivity of n-hexylamine is 64.2%, the selectivity of di-n-hexylamine is 21.1%, and the selectivity of tri-n-hexylamine is 10.6%.

[0048] Example 3: a supported metal catalyst cat.3 prepared in catalyst example 3 is filled in a reactor at 100 ml, and the rest is the same as example 1. The total conversion rate of n-hexanol is 87.3% by gas chromatography analysis, wherein the selectivity of n-hexylamine is 49.2%, the selectivity of di-n-hexylamine is 23.2%, and the selectivity of tri-n-hexylamine is 21.8%.

[0049] The data of Examples 1 to 3 were statistically analyzed as follows, and the results are shown in Table 1.

[0050] Table 1

[0051] As can be seen from Table 1, catalyst cat. 1 is superior to catalyst cat. 2 and catalyst cat. 3, and therefore, Examples 4 to 9 were carried out using catalyst cat. 1.

[0052] Examples 4 to 7, the "molar ratio of ammonia: hydrogen: n-hexanol", "reaction temperature", "reaction pressure" were changed as shown in Table 2, and the rest was the same as Example 1.

[0053] The results are shown in Table 2.

[0054] Table 2

[0055] Examples 8 to 9, the "reaction space velocity" was changed as shown in Table 3, and the rest was the same as Example 1.

[0056] The results are shown in Table 3.

[0057] Table 3

[0058] Comparative Examples 1-1 to 1-4, the active ingredient in Example 1 was changed as shown in Table 4, and the rest was the same as Example 1.

[0059] The results are shown in Table 4.

[0060] Table 4

[0061] Comparative Example 2, "Zn is 4.2 Wt%, Mo is 0.8 Wt%" was changed to "Zn is 2.5 Wt%, Mo is 2.5 Wt%", and the rest was the same as Catalyst Example 1. The obtained catalyst was subjected to amination reaction according to Example 1, and the results are shown in Table 5 below.

[0062] Comparative Example 3, "Zn is 4.2 Wt%" was changed to "Ni is 4.2 Wt%", and the rest was the same as Catalyst Example 1. The obtained catalyst was subjected to amination reaction according to Example 1, and the results are shown in Table 5 below.

[0063] Comparative Example 4, "Zn is 4.2 Wt%" was changed to "Al is 4.2 Wt%", and the rest was the same as Catalyst Example 1. The obtained catalyst was subjected to amination reaction according to Example 1, and the results are shown in Table 5 below.

[0064] Comparative Example 5, change "Zn is 4.2 Wt%, Mo is 0.8 Wt%" to "Zn is 0 Wt%, Mo is 5 Wt%", and the rest is the same as Catalyst Example 1, the obtained catalyst is subjected to amination reaction according to Example 1, and the obtained results are as follows in Table 5.

[0065] Comparative Example 6, change "Mo is 0.8 Wt%" to "Sn is 0.8 Wt%", and the rest is the same as Catalyst Example 1, the obtained catalyst is subjected to amination reaction according to Example 1, and the obtained results are as follows in Table 5.

[0066] Comparative Example 7, change "Mo is 0.8 Wt%" to "Ce is 0.8 Wt%", and the rest is the same as Catalyst Example 1, the obtained catalyst is subjected to amination reaction according to Example 1, and the obtained results are as follows in Table 5.

[0067] Table 5

[0068] Example 10, catalyst stability operation The supported metal catalyst cat.1 after reaction of Example 1 is continuously subjected to reaction according to the method described in Example 1, and the rest is the same as Example 1, the continuous operation days and the corresponding results are as follows in Table 6.

[0069] Table 6

[0070] The present application is also carried out on a large fixed bed reactor device with a catalyst loading of 3.35 tons, and the obtained results have no significant difference from the results obtained in the above cases.

[0071] The above is only a specific embodiment of the present application, but the technical features of the present application are not limited thereto. Any simple change, equivalent replacement or modification made on the basis of the present application to solve the same technical problem and achieve the same technical effect is covered by the protection scope of the present application.

Claims

1. A supported catalyst, characterized in that: Supported catalysts consist of a catalyst support and cobalt, copper, zinc, and molybdenum as active components; The loading of cobalt is 8-16 wt%, the loading of copper is 3-9 wt%, the loading of zinc is 3-6 wt%, and the loading of molybdenum is 0-2 wt%.

2. The supported catalyst according to claim 1, characterized in that: The loading of cobalt is 13.5~15.0 wt%, the loading of copper is 3.5~5.0 wt%, the loading of zinc is 3.5~4.2 wt%, and the loading of molybdenum is 0.8~1.5 wt%.

3. The supported catalyst according to claim 2, characterized in that: The loading of cobalt was 15.0 wt%, copper was 3.5 wt%, zinc was 4.2 wt%, and molybdenum was 0.8 wt%.

4. The method for preparing the supported catalyst according to any one of claims 1 to 3, characterized in that... Includes the following steps: ① Preparation of catalyst support Water and acid were added to pseudoboehmite and guar gum powder, mixed evenly, extruded and dried, heated to 300±30℃ and calcined for 2±0.1 hours, and then heated to 400~500℃ and calcined for 10±0.5 hours to obtain the catalyst support. The mass ratio of pseudoboehmite to guar gum powder is 100:4.5~5.

5. ② According to the set loading amounts of cobalt, copper, zinc, and molybdenum, add cobalt nitrate, copper nitrate, zinc nitrate, and molybdenum nitrate to water to prepare a mixed nitrate solution; The catalyst support was impregnated in a mixed nitrate solution, then dried, and then calcined at 450±50℃ for 5±0.5h to obtain the supported catalyst support. The mixed nitrate solution was completely absorbed by the catalyst support; ③ Activation and reduction of catalysts: The supported catalyst support is activated and reduced in a hydrogen atmosphere at a reduction temperature of 400-500℃ until no more water is produced; thus, the supported catalyst is obtained.

5. The method for preparing the supported catalyst according to claim 4, characterized in that: In step ①, the weight ratio of boehmite:water:nitric acid is 1:1.4~1.6:0.04~0.

06. In step ②, a two-stage impregnation-drying-calcination process is adopted; the impregnation time for each stage is 1.5 ± 0.5 hours.

6. The method for preparing the supported catalyst according to claim 4 or 5, characterized in that: The drying in step ① is as follows: drying at 120±20℃ for 3±0.5h; The drying process in step ② is as follows: drying at 120±20℃ for 3±0.5h.

7. The method for preparing the supported catalyst according to claim 6, characterized in that: In step ③: airspeed 10h -1 The reduction heating rate is 3~10℃ / min; the reduction temperature is 450℃.

8. A method for preparing n-hexylamine from n-hexanol, characterized in that: Using the supported catalyst according to any one of claims 1 to 3, the method includes the following steps: 1) A supported catalyst is set as the catalyst bed in the reactor. Hexanol, liquid ammonia, and hydrogen are introduced into the vaporizer at a molar ratio of 1:1~6:1~5, heated and vaporized, and then enter the reactor to undergo an amination reaction in the catalyst bed. The reaction temperature is 140~250℃; the reaction pressure is 0.2~1.5 MPa; and the reaction space velocity is 0.1~0.5 h⁻¹. -1 ; 2) The crude product after the reaction is cooled naturally to form a liquid phase and a gas phase, wherein the liquid phase contains n-hexylamine, which is the product.

9. The method for preparing n-hexylamine from n-hexanol according to claim 8, characterized in that... In step 2): The liquid phase enters the crude product tank, while the gas phase is discharged to the water absorption system through the top pipeline of the crude product tank.

10. The method for preparing n-hexylamine from n-hexanol according to claim 8 or 9, characterized in that: The n-hexylamine includes n-hexylamine, di-n-hexylamine, and tri-n-hexylamine, with n-hexylamine being the most common.

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