1, 3-xylylenediamine (MXDA) hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention provides a catalyst for preparing 1, 3-cyclohexanedimethylamine (1, 3-BAC) through hydrogenation of 1, 3-xylylenediamine (MXDA), which is characterized in that the catalyst is mainly composed of an active component, an alkali metal modifier, an accelerant and a carrier, the active component is ruthenium trichloride, the alkali metal modifier is lithium hydroxide, and the accelerant is one or more of Pr, Nd, Mo, Lu and Tm, preferably Mo; the carrier is an SAPO-34 molecular sieve. Compared with the prior art, the catalyst can inhibit the side reaction at lower reaction temperature and pressure and higher substrate concentration and reaction space velocity, higher raw material conversion rate and selectivity are obtained, and the catalyst is stable in performance, long in service life, capable of remarkably improving the production efficiency and reducing the production cost and beneficial to industrial application.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalyst preparation, in particular to a catalyst for preparing 1,3-cyclohexanedimethylamine by selective hydrogenation of 1,3-xylylenediamine. BACKGROUND

[0002] 1,3-cyclohexanedimethylamine (1,3-BAC) is an important chemical intermediate, which has a wide range of applications in the chemical industry. It is mainly used as an epoxy resin curing agent, which has the advantages of small volatility, difficulty in crystallization, fast curing speed, resistance to yellowing, good weather resistance, and good transparency, and is widely used in the fields of joint sealant, composite material, epoxy floor, and structural adhesive. Especially as a curing agent for joint sealant, it has an irreplaceable role. It can also be used to synthesize polyurethane with high refractive index and good transparency.

[0003] Patent EP0703213 uses impregnation method to prepare Ru / Al2O3 catalyst with Ru metal loading of 2% (by weight), and 1,3-cyclohexanedimethylamine as solvent, under the conditions of reaction temperature 120℃ and reaction pressure 10MPa, m-xylylenediamine hydrogenation reaction is carried out. Liquid ammonia is added as inhibitor, the yield of 1,3-cyclohexanedimethylamine is 94%, the by-products are 2.7% of 3-aminomethyl-1-methylcyclohexane, 2.5% of 3-methylbenzylamine, 0.4% of m-xylylenediamine, and 0.4% of m-xylene.

[0004] Patent US4181680 uses impregnation method to prepare Ru / Al2O3 catalyst with Ru metal loading of 5% (by weight), under the conditions of reaction temperature 130℃ and reaction pressure 16MPa, the yield of 1,3-cyclohexanedimethylamine is 88%.

[0005] Patent CN110433823A prepares metal oxide-Al2O3 catalyst carrier by sintering, and loads Ru on the carrier by impregnation method, under the conditions of reaction temperature 120℃ and pressure 6MPa, the reaction time is 210min, without using deamination inhibitor, the selectivity of 1,3-cyclohexanedimethylamine is 97.8%, and the yield is 97.1%. The loaded metal oxide easily blocks the pores of Al2O3, reducing the catalytic efficiency.

[0006] The existing technology mostly uses Al2O3 or activated carbon to support metal ruthenium as catalyst. Due to the flammable nature of activated carbon, the control of reaction conditions is extremely strict, which is not conducive to operation. Al2O3 promotes the occurrence of deamination side reactions due to the existence of surface acidic sites, reducing the selectivity of the product. The active component is loaded on the carrier by simple impregnation method, and there are problems of active component loss, catalytic efficiency decline, and catalyst regeneration difficulty in the use of catalyst.

[0007] 1,3-phenyldimethylamine hydrogenation reaction, the main side reaction is the condensation of primary amine group into secondary amine, the hydrogenation cracking of C-N bond between tertiary amine and amino group, and the deamination reaction. In the prior art, liquid ammonia, small molecule organic amine or alkali metal hydroxide is used as deamination inhibitor, which provides an alkaline environment for the system to inhibit the side reaction. Liquid ammonia and small molecule organic amine are easy to volatilize and difficult to separate from 1,3-cyclohexanedimethylamine. Although the alkali metal hydroxide does not deactivate the catalyst, it is easy to cause corrosion to the equipment and poses a threat to production safety. The metal oxide is easy to block the pore channel of the carrier.

[0008] In view of the problems that the active component of the existing catalyst is easy to lose, side reactions are easy to occur, and the deamination inhibitor is difficult to separate from the product, it is necessary to develop a 1,3-phenyldimethylamine hydrogenation catalyst with long service life, high selectivity and easy separation of product. SUMMARY

[0009] In view of the problems of the prior art and safety, the present application provides a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenation of 1,3-phenyldimethylamine, characterized in that the catalyst mainly comprises an active component, an alkali metal modifier, a promoter and a carrier; the active component is ruthenium trichloride, the alkali metal modifier is lithium hydroxide, the promoter is one or more of Pr, Nd, Mo, Lu and Tm, and Mo is preferred; and the carrier is SAPO-34 molecular sieve.

[0010] A preparation method of a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenation of 1,3-phenyldimethylamine, comprising the following steps:

[0011] (1) Preparation of SAPO-34 molecular sieve with isomorphous substitution of active metal and promoter: pseudo-boehmite is added to a mixture of phosphoric acid, template agent and deionized water, and ruthenium trichloride and metal salt of the promoter are added, and then organosiloxane is added after stirring uniformly, and the gel is fully stirred to form a uniform gel, and then the gel is subjected to constant temperature crystallization, and then filtration, water washing, drying and calcination to obtain the SAPO-34 molecular sieve with isomorphous substitution;

[0012] (2) Modification of alkali metal modifier: lithium hydroxide is dissolved in deionized water to form a solution, and the SAPO-34 molecular sieve with isomorphous substitution is immersed in the solution, and the solution is refluxed at the same time, and then the catalyst precursor modified by the alkali metal is obtained by filtration, washing and drying;

[0013] (3) Catalyst activation: the catalyst precursor is immersed in an aqueous hydrazine solution, and the pH is adjusted to 8-12 with ammonia water, and then the catalyst product is obtained by heating reduction, filtration, washing and drying.

[0014] Further, the molar ratio of ruthenium trichloride, promoter, organosiloxane in step (1) is 1:1-1.5:1-1.5.

[0015] Further, the molar ratio of ruthenium trichloride, promoter, organosiloxane in step (1) is 1:1-1.5:1-1.5.

[0016] Further, the molar ratio of organosiloxane, pseudo-boehmite, phosphoric acid, template agent and deionized water in step (1) is 1:1.2:1:1.5:60.

[0017] Further, the soluble salt of the promoter is one or more of nitrate, chloride, sulfate, carbonate and acetate of the metal in Mo, and the nitrate is preferred.

[0018] Further, the organosiloxane is one or more of KH-570, KH-590, A-1100 and Y-5691, and the KH-590 is preferred.

[0019] Further, the template agent is one or more of diethylamine, tetraphosphate and polyhexamethylene biguanide, and the tetraphosphate is preferred.

[0020] Further, the crystallization temperature is 100-130 DEG C, the crystallization time is 5h, the calcination temperature is 400-600 DEG C, and the calcination time is 1h.

[0021] Further, the crystallization temperature is 120 DEG C, the crystallization time is 5h, the calcination temperature is 500 DEG C, and the calcination time is 1h.

[0022] Further, the molar ratio of lithium hydroxide in step (2), deionized water in step (2) and organosiloxane in step (1) is 2:5:1.

[0023] Further, the immersion temperature in step (2) is 50-60 DEG C, and 55 DEG C is preferred; the reflux time is 2-15h, and 8h is preferred.

[0024] Further, the molar ratio of hydrazine hydrate and ruthenium trichloride in step (3) is 15-20:1; the mass fraction of hydrazine hydrate in the hydrazine hydrate aqueous solution is 20-40%; and the reduction temperature in step (3) is 30-60 DEG C, and the reduction time is 50min.

[0025] The present application has the following advantages:

[0026] (1) The present application introduces the metal salt of active metal and promoter in the formation process of SAPO-34 molecular sieve skeleton, so that the molecular sieve and the active metal are combined closely, the component loss rate is greatly reduced, the reduction state of the active metal is easily maintained, and the service life of the catalyst is prolonged.

[0027] (2) The present application can make the carrier keep alkaline for a long time by firmly combining lithium hydroxide in the carrier, and does not destroy the original channel of the carrier, so that the deamination side reaction of raw materials and product molecules is effectively inhibited, and free small molecule amine substances are not used as deamination inhibitors, so that the product is easy to separate;

[0028] (3) The catalyst of the present application is used for selectively hydrogenating 1,3-xylylenediamine to prepare 1,3-cyclohexanedimethylamine, the conversion rate reaches 100%, the selectivity of 1,3-cyclohexanedimethylamine reaches more than 99.2%, and the catalyst has the characteristics of not easy to lose active components, long service life and good selectivity. DETAILED DESCRIPTION

[0029] Example 1:

[0030] (1) Preparation of Ru-Mo isomorphous substitution SAPO-34 molecular sieve: KH-590, pseudo-boehmite, phosphoric acid, tetraphosphoric acid ester and deionized water are weighed in a molar ratio of 1:1.2:1:1.5:60. The pseudo-boehmite is added to a mixture of phosphoric acid (concentration 80wt%), tetraphosphoric acid ester and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 are added, and after stirring uniformly, KH-590 is added, wherein the molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-590 is 1:1.2:1. The gel is fully stirred at 30℃ until a uniform gel is obtained, the gel is sealed in a stainless steel autoclave, and crystallization is carried out at 120℃ for 5h. After complete crystallization, the product is centrifuged and filtered, and washed with 80℃ distilled water until the pH value is constant. The product is dried at 100℃, and then calcined at 500℃ in a muffle furnace for 1h to obtain Ru-Mo isomorphous substitution SAPO-34.

[0031] (2) Alkali metal modifier modification: lithium hydroxide is dissolved in deionized water to form a solution, and the isomorphously substituted SAPO-34 molecular sieve is immersed in the solution, and the solution is refluxed at the same time, and then filtered, washed and dried to obtain an alkali metal modified catalyst precursor; wherein the molar ratio of lithium hydroxide, deionized water and KH-590 in step (1) is 2:5:1; the immersion temperature is 55℃, and the refluxing time is 8h.

[0032] (3) Catalyst activation: the lithium hydroxide modified catalyst precursor is immersed in an aqueous hydrazine hydrate solution (hydrazine hydrate content 30wt%), wherein the molar ratio of hydrazine hydrate to ruthenium trichloride is 18:1, and the pH value is adjusted to 10 with ammonia water. The reduction temperature is heated to 50℃, and the reduction is carried out for 50min. The catalyst product C1 is obtained by centrifugal filtration, washing and drying.

[0033] Example 2:

[0034] (1) Ru-Mo isomorphous substitution SAPO-34 molecular sieve preparation: KH-590, pseudo-boehmite, phosphoric acid, tetraphosphoric acid ester and deionized water are weighed in a molar ratio of 1:1.2:1:1.5:60. The pseudo-boehmite is added to the mixture of phosphoric acid (concentration 80wt%), tetraphosphoric acid ester and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 are added. After stirring, KH-590 is added, wherein the molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-590 is 1:1.5:1.5. The gel is fully stirred at 30°C until a uniform gel is obtained. The gel is sealed in a stainless steel autoclave and crystallized at 130°C for 5h. After complete crystallization, the product is centrifuged and filtered, washed with 80°C distilled water until the pH value is constant, dried at 100°C, and calcined at 600°C for 1h in a muffle furnace to obtain Ru-Mo isomorphous substitution SAPO-34.

[0035] (2) Alkali metal modifier modification: lithium hydroxide is dissolved in deionized water to form a solution, and the isomorphously substituted SAPO-34 molecular sieve is immersed in the solution, and the solution is refluxed, then filtered, washed and dried to obtain an alkali metal modified catalyst precursor; wherein the molar ratio of lithium hydroxide, deionized water and KH-590 in step (1) is 2:5:1; the immersion temperature is 60°C and the refluxing time is 15h.

[0036] (3) Catalyst activation: the lithium hydroxide modified catalyst precursor is immersed in an aqueous hydrazine hydrate solution (hydrazine hydrate content 40wt%), wherein the molar ratio of hydrazine hydrate to ruthenium trichloride is 20:1, and the pH is adjusted to 10 with ammonia water. The reduction temperature is heated to 60°C and the reduction is carried out for 50min. The catalyst product C2 is obtained by centrifugal filtration, washing and drying.

[0037] Example 3:

[0038] (1) Ru-Mo isomorphous substitution SAPO-34 molecular sieve preparation: KH-590, pseudo-boehmite, phosphoric acid, tetraphosphoric acid ester and deionized water are weighed in a molar ratio of 1:1.2:1:1.5:60. The pseudo-boehmite is added to the mixture of phosphoric acid (concentration 80wt%), tetraphosphoric acid ester and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 are added. After stirring, KH-590 is added, wherein the molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-590 is 1:1:1. The gel is fully stirred at 30°C until a uniform gel is obtained. The gel is sealed in a stainless steel autoclave and crystallized at 100°C for 5h. After complete crystallization, the product is centrifuged and filtered, washed with 80°C distilled water until the pH value is constant, dried at 100°C, and calcined at 400°C for 1h in a muffle furnace to obtain Ru-Mo isomorphous substitution SAPO-34.

[0039] (2) Alkali modifier modification: Lithium hydroxide is dissolved in deionized water to prepare a solution, and the isomorphously substituted SAPO-34 molecular sieve is immersed in the solution, and the solution is refluxed at the same time, and then filtered, washed and dried to obtain an alkali-modified catalyst precursor; wherein the molar ratio of lithium hydroxide, deionized water and KH-590 in step (1) is 2:5:1; the immersion temperature is 50°C, and the refluxing time is 2h.

[0040] (3) Catalyst activation: The lithium hydroxide-modified catalyst precursor is immersed in an aqueous hydrazine hydrate solution (hydrazine hydrate content 20wt%), wherein the molar ratio of hydrazine hydrate to ruthenium trichloride is 15:1, adjusted to pH = 10 with ammonia water, heated to reduce the temperature to 30°C, reduced for 50 min, and then centrifuged, filtered, washed and dried to obtain catalyst product C3.

[0041] Example 4:

[0042] (1) Preparation of Ru-Mo isomorphously substituted SAPO-34 molecular sieve: KH-590, pseudoboehmite, phosphoric acid, tetraphosphoric acid ester and deionized water are weighed according to the molar ratio of 1:1:1:1.5:60. The pseudoboehmite is added to the mixture of phosphoric acid (concentration 80wt%), tetraphosphoric acid ester and deionized water, and then hydrous ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 are added. After stirring uniformly, KH-590 is added, wherein the molar ratio of hydrous ruthenium trichloride, Mo(NO3)3 and KH-590 is 1:0.5:0.5. The gel is fully stirred at 30°C until a uniform gel is obtained. The gel is sealed in a stainless steel autoclave and crystallized at 90°C for 5h. After complete crystallization, the product is centrifuged, filtered, washed with 80°C distilled water until the pH value is constant, dried at 100°C, and then calcined at 300°C for 1h in a muffle furnace to obtain Ru-Mo isomorphously substituted SAPO-34.

[0043] (2) Alkali modifier modification: Lithium hydroxide is dissolved in deionized water to prepare a solution, and the isomorphously substituted SAPO-34 molecular sieve is immersed in the solution, and the solution is refluxed at the same time, and then filtered, washed and dried to obtain an alkali-modified catalyst precursor; wherein the molar ratio of lithium hydroxide, deionized water and KH-590 in step (1) is 2:3:1; the immersion temperature is 40°C, and the refluxing time is 1h.

[0044] (3) Catalyst activation: The lithium hydroxide-modified catalyst precursor is immersed in an aqueous hydrazine hydrate solution (hydrazine hydrate content 10wt%), wherein the molar ratio of hydrazine hydrate to ruthenium trichloride is 10:1, adjusted to pH = 10 with ammonia water, heated to reduce the temperature to 20°C, reduced for 50 min, and then centrifuged, filtered, washed and dried to obtain catalyst product C4.

[0045] Example 5:

[0046] (1) Preparation of SAPO-34 molecular sieve with Ru-Mo isomorphous substitution: KH-590, pseudo-boehmite, phosphoric acid, tetraphosphoric acid ester and deionized water were weighed according to the molar ratio of 1:2:2:1.5:60. The pseudo-boehmite was added to the mixture of phosphoric acid (concentration 80wt%), tetraphosphoric acid ester and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 were added. After stirring, KH-590 was added, wherein the molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-590 was 1:2:2. The mixture was stirred at 30°C until a uniform gel was obtained. The gel was sealed in a stainless steel autoclave and crystallized at 140°C for 5h. After complete crystallization, the product was centrifuged and filtered, and then washed with 80°C distilled water until the pH value was constant. The product was dried at 100°C and then calcined at 700°C for 1h in a muffle furnace to obtain SAPO-34 with Ru-Mo isomorphous substitution.

[0047] (2) Modification with alkali metal modifier: Lithium hydroxide was dissolved in deionized water to form a solution. The isomorphously substituted SAPO-34 molecular sieve was immersed in the solution, and the solution was refluxed at the same time. Then the catalyst precursor modified with alkali metal was obtained by filtering, washing and drying. The molar ratio of lithium hydroxide, deionized water and KH-590 in step (1) was 2:8:1. The immersion temperature was 70°C, and the refluxing time was 20h.

[0048] (3) Catalyst activation: The catalyst precursor modified with lithium hydroxide was immersed in an aqueous hydrazine hydrate solution (hydrazine hydrate content 50wt%), wherein the molar ratio of hydrazine hydrate to ruthenium trichloride was 25:1. The pH value was adjusted to 10 with ammonia water, and the reduction temperature was heated to 70°C. The reduction was carried out for 50min. The catalyst product C5 was obtained by centrifugal filtration, washing and drying.

[0049] Example 6:

[0050] A commercially available Ru metal supported Ru / Al2O3 catalyst with a loading of 5wt% was purchased and denoted as catalyst C6.

[0051] Example 7:

[0052] (1) Preparation of SAPO-34 molecular sieve with Ru-Mo isomorphous substitution: KH-590, pseudo-boehmite, phosphoric acid, tetrametaphosphoric acid ester and deionized water were weighed in a molar ratio of 1:1.2:1:1.5:60. The pseudo-boehmite was added to a mixture of phosphoric acid (concentration 80wt%), tetrametaphosphoric acid ester and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 were added. After stirring, KH-590 was added. The molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-590 was 1:1.2:1.2. The mixture was stirred at 30°C until a uniform gel was obtained. The gel was sealed in a stainless steel autoclave and crystallized at 120°C for 5h. After complete crystallization, the product was centrifuged and filtered, and then washed with 80°C distilled water until the pH value was constant. The product was dried at 100°C and then calcined at 500°C for 1h in a muffle furnace to obtain SAPO-34 with Ru-Mo isomorphous substitution.

[0053] (2) The isomorphously substituted SAPO-34 molecular sieve was immersed in a deionized water solution, and the solution was refluxed. Then the catalyst precursor was obtained by filtering, washing and drying. The molar ratio of deionized water to KH-590 in step (1) was 5:1. The immersion temperature was 55°C, and the refluxing time was 8h.

[0054] (3) Catalyst activation: the catalyst precursor was immersed in an aqueous solution of hydrazine hydrate (hydrazine hydrate content 30wt%), and the molar ratio of hydrazine hydrate to ruthenium trichloride was 18:1. Ammonia water was used to adjust the pH value to 10. The reduction temperature was heated to 50°C, and the reduction time was 50min. The catalyst product C7 was obtained by centrifugation, washing and drying.

[0055] Examples 8-14

[0056] The catalysts of Examples 1-7 were used respectively to carry out the hydrogenation reaction of 1,3-benzene dimethylamine in a fixed bed. The process conditions were as follows:

[0057] The catalyst was loaded into a fixed bed reaction tube, and quartz wool was filled at both ends of the bed. Nitrogen was used to detect the airtightness. If the airtightness was good, nitrogen and hydrogen were used to replace three times. Hydrogen was passed through a mass flow meter, and the flow rate was 0.08h -1 . The pressure was adjusted to 6MPa, and the reactor was controlled to heat to 110°C. After the pressure and temperature were stable, the isopropyl alcohol solution of 1,3-benzene dimethylamine (1,3-benzene dimethylamine mass concentration 60%) was passed into the reactor using a high-pressure constant-flow pump, and the flow rate was 1h -1 . Under the above conditions, the hydrogenation reaction was carried out. After 10h, the hydrogen was emptied, and the product was separated. The product was analyzed by a gas chromatograph, and the reaction results are shown in Table 1.

[0058] Table 1 Reaction results of catalysts prepared in Examples 8-14 applied to hydrogenation of 1,3-dimethylamine

[0059]

[0060]

[0061] As shown in Table 1, catalyst C1 has the best catalytic reaction effect.

[0062] Examples 15-21

[0063] Based on catalysts C1 and C7 respectively, continuous hydrogenation experiments of 1,3-dimethylamine were carried out according to the hydrogenation reaction process of Examples 8-14 to test the service life of the catalysts, and the results are shown in Table 2.

[0064] Table 2 Results of continuous hydrogenation experiments of 1,3-dimethylamine

[0065]

[0066] As shown in Table 2, the catalyst C1 of the present application has been stably operated for 4000h without obvious decrease in conversion rate and selectivity, while the conversion rate and selectivity of catalyst C7 decrease seriously after 1000h operation. Due to the isomorphous substitution of active metal, the synergistic effect of promoter and active metal, the modification of carrier by lithium hydroxide and selective adsorption, the catalyst of the present application has the characteristics of long service life, high selectivity, easy separation of product and the like.

[0067] Although the specific embodiments of the present application have been described above, it is not intended to limit the scope of protection of the present application, and those skilled in the art should understand that various modifications or changes made on the basis of the technical solutions of the present application without creative labor are still within the scope of protection of the present application.

Claims

1. A catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenation of 1,3-phenylenediamine, characterized in that: The catalyst mainly consists of an active component, an alkali metal modifier, a promoter and a carrier; the active component is ruthenium trichloride, the alkali metal modifier is lithium hydroxide, the promoter is one or more of Pr, Nd, Mo, Lu, Tm, preferably Mo; and the carrier is SAPO-34 molecular sieve.

2. A method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 1, comprising the following steps: (1) Preparation of SAPO-34 molecular sieve with isomorphous substitution of active metal and promoter: pseudo-boehmite is added to a mixture of phosphoric acid, template and deionized water, ruthenium trichloride and metal salt of promoter are added, and after stirring evenly, organosiloxane is added and stirred thoroughly until a uniform gel is formed. The gel is crystallized at a constant temperature, and then filtered, washed with water, dried and calcined to obtain isomorphous substitution of SAPO-34 molecular sieve; (2) Alkali metal modifier modification: lithium hydroxide is dissolved in deionized water to prepare a solution, the isomorphously substituted SAPO-34 molecular sieve is impregnated in the solution, and the solution is refluxed, then filtered, washed, and dried to obtain an alkali metal-modified catalyst precursor; (3) Catalyst activation: The catalyst precursor is immersed in a hydrazine hydrate aqueous solution, adjusted to a pH of 8 to 12 with ammonia water, heated for reduction, and then filtered, washed, and dried to obtain a catalyst product.

3. The method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 2, characterized in that: In the step (1), the molar ratio of ruthenium trichloride, accelerator and organosiloxane is 1:1-1.5:1-1.

5.

4. The method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 2, characterized in that: In the step (1), the molar ratio of the organosiloxane, pseudo-boehmite, phosphoric acid, template and deionized water is 1:1.2:1:1.5:

60.

5. The method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 2, characterized in that: The soluble salt of the promoter is one or more of nitrate, chloride, sulfate, carbonate and acetate of the metal in Mo, preferably nitrate.

6. The method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 2, characterized in that: The organosiloxane is one or more of KH-570, KH-590, A-1100, and Y-5691, preferably KH-590.

7. The method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 2, characterized in that: The template agent is one or more of diethylamine, tetrapolyphosphate, and polyhexamethylene biguanide, preferably tetrapolyphosphate.

8. The method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 2, characterized in that: The crystallization temperature is 100-130° C., and the crystallization time is 5 hours; the sintering temperature is 400-600° C., and the sintering time is 1 hour.

9. The method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 2, characterized in that: The molar ratio of lithium hydroxide in step (2), deionized water in step (2), and organosiloxane in step (1) is 2:5:1; the immersion temperature in step (2) is 50-60° C., preferably 55° C.; and the reflux time is 2-15 hours, preferably 8 hours.

10. The method for preparing a catalyst for preparing 1,3-cyclohexanedimethylamine by hydrogenating 1,3-phenylenediamine according to claim 2, characterized in that: The molar ratio of hydrazine hydrate to ruthenium trichloride in step (3) is 15-20:1; the mass fraction of hydrazine hydrate in the hydrazine hydrate aqueous solution is 20-40%; the reduction temperature in step (3) is 30-60° C., and the reduction time is 50 minutes.

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