M-phenylenediamine hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention provides a catalyst for preparing 1, 3-cyclohexanediamine by m-phenylenediamine hydrogenation, 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 SSZ-13 molecular sieve. Compared with the prior art, the catalyst can inhibit side reaction at lower reaction temperature and pressure and higher substrate concentration and reaction space velocity, higher raw material conversion rate and 1, 3-cyclohexanediamine selectivity are obtained, the catalyst is stable in performance and long in service life, the production efficiency can be remarkably improved, the production cost is reduced, and the catalyst is suitable for industrial production. The industrial application is facilitated.

Description

TECHNICAL FIELD

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

[0002] 1,3-cyclohexanediamine is widely used in plastics and dye production (mainly rubber compounding agent and epoxy resin curing agent in plastics; and mainly important intermediate for preparing azo dyes and sulfur dyes in dyes). In recent years, with the increasing demand for high-temperature-resistant materials, the demand for 1,3-cyclohexanediamine also increases, and it plays an important role in industrial production.

[0003] The existing technology discloses a synthesis method of 1,3-cyclohexanediamine, which includes:

[0004] (1) Junya Cao, Fenggang Han, etc. take m-phenylenediamine as a raw material, and under the action of a self-made Ru / g-C3N4 (25 wt% of the weight of the raw material) catalyst, the temperature is 130 DEG C, the pressure is 5 MPa, and tetrahydrofuran is used as a solvent, and the reaction conversion rate is 96%, and the selectivity is 82%;

[0005] (2) Ma Hongxian takes p-phenylenediamine as a raw material, and uses Ru / Al2O3 as a catalyst, lithium hydroxide as an additive, and a mixture of water and isopropanol as a solvent, and investigates the preparation of the catalyst and the hydrogenation process, and when investigating the stability of the catalyst, it is found that after the catalyst is used for four times, the conversion rate of the raw material decreases from 65% to 37%;

[0006] (3) Yang Yanmi studies the preparation process of 1,3-cyclohexanediamine by selective hydrogenation of m-phenylenediamine, and uses LiOH modified Ru / Al2O3 as a catalyst, and tetrahydrofuran as a solvent, and the initial reaction conversion rate reaches 100%, and the selectivity is 97%, however, when the solid bed continuous stability is investigated, it is found that the specific surface area and pore volume of the catalyst decrease, Ru is seriously lost, and the conversion rate rapidly decreases.

[0007] (5) Chinese patent CN117069594A takes m-dinitrobenzene as a raw material, and adopts a two-step hydrogenation method to prepare 1,3-cyclohexanediamine, which is complicated to operate and is not conducive to industrial mass production.

[0008] In addition, 1,3-cyclohexanediamine has two isomers, trans-1,3-cyclohexanediamine and cis-1,4-cyclohexanediamine, and the structural formula is as follows:

[0009]

[0010] The trans-isomer is more stable and superior in preparing a polymer, and a higher proportion of the trans-isomer is often required in synthesis.

[0011] In summary, existing technologies often use Al2O3 or activated carbon-supported ruthenium as catalysts. Activated carbon, due to its flammability, requires extremely strict control of reaction conditions, making it difficult to operate. The presence of acidic sites on the surface of Al2O3 promotes the deamination side reaction, reducing product selectivity. The active component is loaded onto the support via a simple impregnation method, which can lead to active component loss during use, reduced catalytic efficiency, and difficulty in regenerating the catalyst. Summary of the Invention

[0012] In response to problems in the existing technology and safety, the present invention provides a catalyst for preparing 1,3-cyclohexanediamine by hydrogenating m-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, and Tm, preferably Mo; and the carrier is SSZ-13 molecular sieve.

[0013] A method for preparing a catalyst for hydrogenating m-phenylenediamine to prepare 1,3-cyclohexanediamine, comprising the following steps:

[0014] (1) Preparation of SSZ-13 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 the mixture is stirred evenly before adding organosiloxane and stirring thoroughly until a uniform gel is formed. The gel is crystallized at a constant temperature, filtered, washed with water, dried and calcined to obtain isomorphous substitution of SSZ-13 molecular sieve;

[0015] (2) Alkali metal modifier modification: lithium hydroxide is dissolved in deionized water to prepare a solution, isomorphously substituted SSZ-13 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;

[0016] (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.

[0017] Furthermore, in step (1), the molar ratio of ruthenium trichloride, accelerator, and organosiloxane is 1:1-1.5:0.8-1.2.

[0018] Furthermore, in step (1), the molar ratio of ruthenium trichloride, accelerator and organosiloxane is 1:1.2:1.

[0019] Further, the molar ratio of the organosiloxane, the pseudoboehmite, the phosphoric acid, the template agent and the deionized water in step (1) is 1:1:1.2:1.5:50.

[0020] Further, the soluble salt of the promoter is one or more of the nitrate salt, the chloride salt, the sulfate salt, the carbonate salt and the acetate salt of the metal in Mo, and is preferably the nitrate salt.

[0021] Further, the organosiloxane is one or more of KH-570, KH-590, A-1100 and Y-5691, and is preferably KH-570.

[0022] Further, the template agent is one or more of diethylamine, tetraphosphate and polyhexamethylene biguanide, and is preferably diethylamine.

[0023] Further, the crystallization temperature is 100-150℃, and the crystallization time is 5h; the calcination temperature is 300℃-700℃, and the calcination time is 1h.

[0024] Further, the crystallization temperature is 120℃, and the crystallization time is 5h; the calcination temperature is 400℃, and the calcination time is 1h.

[0025] Further, the molar ratio of the lithium hydroxide in step (2), the deionized water in step (2) and the organosiloxane in step (1) is 3:7:1;

[0026] Further, the immersion temperature in step (2) is 50-70℃, and is preferably 60℃; and the reflux time is 0.5-24h, and is preferably 10h.

[0027] Further, in step (3), the pH is adjusted to 10 with ammonia water.

[0028] Further, in step (3), the molar ratio of the hydrazine hydrate to the ruthenium trichloride is 10-20:1; and the mass fraction of the hydrazine hydrate in the hydrazine hydrate aqueous solution is 5-90%.

[0029] Further, in step (3), the reduction temperature is 20-70℃, and the reduction time is 50min.

[0030] Further, in step (3), the molar ratio of the hydrazine hydrate to the ruthenium trichloride is 15:1; the mass fraction of the hydrazine hydrate in the hydrazine hydrate aqueous solution is 10%; the reduction temperature in step (3) is 60℃, and the reduction time is 50min.

[0031] The SSZ-13 molecular sieve of the present application has a special three-dimensional pore structure and a large specific surface area, and is different from carriers such as activated carbon and Al2O3, and the pore structure of the SSZ-13 molecular sieve is formed by AlO4 and SiO4 tetrahedrons connected head to tail through oxygen atoms and arranged orderly. The arrangement forms ellipsoidal cages with eight-membered ring structures (0.73 nm x 1.2 nm) and three-dimensional cross-pore structures, and the pore size is 0.38 nm x 0.38 nm. The structure enables the SSZ-13 molecular sieve to effectively promote the conversion of small molecule compounds in a catalytic reaction, and the molecular sieve has a preferential selective adsorption effect on polar, unsaturated and easily polarized molecules. M-phenylenediamine is a polar compound with -NH2 polar groups, and the aromatic ring therein is easily polarized, and can have a strong adsorption effect in the molecular sieve. Since the molecular diameter of m-phenylenediamine is moderate, the m-phenylenediamine can enter the pores of the SSZ-13 molecular sieve and be adsorbed. The aromatic ring of the hydrogenated m-phenylenediamine is converted into the aliphatic ring structure of 1,3-cyclohexanediamine, the adsorption of the SSZ-13 molecular sieve on the product 1,3-cyclohexanediamine is weakened, which is beneficial to inhibit the deamination side reaction of 1,3-cyclohexanediamine and improve the selectivity.

[0032] The present application has the following beneficial effects:

[0033] (1) The present application uses the SSZ-13 molecular sieve as a catalyst carrier, and since the pore structure of the molecular sieve is formed by AlO4 and SiO4 tetrahedrons connected head to tail through oxygen atoms and arranged orderly, the catalyst has a preferential selective adsorption effect on polar, unsaturated and easily polarized molecules, thereby enhancing the adsorption of the catalyst on m-phenylenediamine molecules and weakening the adsorption of the catalyst on the product 1,3-cyclohexanediamine, which is beneficial to inhibit the deamination side reaction of 1,3-cyclohexanediamine and improve the selectivity;

[0034] (2) The present application introduces the metal salts of active metals and promoters into the formation process of the SSZ-13 molecular sieve framework, so that the molecular sieve is combined closely with the active metals, the component loss rate is greatly reduced, the active metal is easily maintained in a reduced state, and the service life of the catalyst is prolonged;

[0035] (3) The present application enables the carrier to maintain alkalinity for a long time by firmly combining lithium hydroxide in the carrier, and does not damage the original pores 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, thereby making the product easy to separate;

[0036] (4) The catalyst of the present application is used for preparing 1,3-cyclohexanediamine by selectively hydrogenating m-phenylenediamine, the conversion rate of m-phenylenediamine reaches 100%, the selectivity of 1,3-cyclohexanediamine reaches more than 99.1%, and the catalyst has the characteristics of difficult component loss, long service life and good selectivity. DETAILED DESCRIPTION

[0037] Example 1

[0038] (1) Preparation of Ru-Mo isomorphously substituted SSZ-13 molecular sieve: KH-570, pseudoboehmite, phosphoric acid, diisopropanolamine and deionized water were weighed according to the molar ratio of 1:1:1.2:1.5:50. The pseudoboehmite was added to the mixture of phosphoric acid (concentration 80wt%), diisopropanolamine and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 were added. After stirring, KH-570 was added, wherein the molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-570 was 1:1.2:1. The gel 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, washed with 80°C distilled water until the pH value was constant, dried at 100°C, and calcined at 400°C in a muffle furnace for 1h to obtain Ru-Mo isomorphously substituted SSZ-13.

[0039] (2) Modification by alkali metal modifier: Lithium hydroxide was dissolved in deionized water to form a solution. The isomorphously substituted SSZ-13 molecular sieve was immersed in the solution, and the solution was refluxed at the same time. Then the catalyst precursor modified by alkali metal was obtained by filtering, washing and drying. The molar ratio of lithium hydroxide, deionized water and KH-570 in step (1) was 3:7:1. The immersion temperature was 60°C, and the refluxing time was 10h.

[0040] (3) Catalyst activation: The catalyst precursor modified by lithium hydroxide was immersed in an aqueous hydrazine hydrate solution (hydrazine hydrate content 10wt%), wherein the molar ratio of hydrazine hydrate to ruthenium trichloride was 15:1. The pH value was adjusted to 10 with ammonia water, and the reduction temperature was heated to 60°C. The catalyst product C1 was obtained by reduction for 50min, centrifugal filtration, washing and drying.

[0041] Example 2

[0042] (1) Ru-Pr isomorphously substituted SSZ-13 molecular sieve preparation: KH-590, pseudoboehmite, phosphoric acid, diisopropanolamine and deionized water are weighed in a molar ratio of 1:1:1.2:1.5:50. The pseudoboehmite is added to a mixture of phosphoric acid (concentration 80wt%), diisopropanolamine and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Pr(NO3)3 are added. After stirring, KH-590 is added, wherein the molar ratio of hydrated ruthenium trichloride, Pr(NO3)3 and KH-590 is 1:1.2:1. The mixture is stirred at 30°C until a uniform gel is obtained. The gel is sealed in a stainless steel autoclave and crystallized at 120°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-Pr isomorphously substituted SSZ-13.

[0043] (2) Alkali metal modifier modification: lithium hydroxide is dissolved in deionized water to form a solution, and the isomorphously substituted SSZ-13 molecular sieve is immersed in the solution while the solution is refluxed. Then the catalyst precursor is obtained by filtering, washing and drying. The molar ratio of lithium hydroxide, deionized water and KH-590 in step (1) is 3:7:1. The immersion temperature is 60°C and the refluxing time is 10h.

[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 and ruthenium trichloride is 15:1. The pH value is adjusted to 10 with ammonia water, and the reduction temperature is heated to 60°C. The catalyst product C2 is obtained by reduction for 50min, centrifugal filtration, washing and drying.

[0045] Example 3:

[0046] (1) Ru-Mo isomorphously substituted SSZ-13 molecular sieve preparation: KH-570, pseudoboehmite, phosphoric acid, diisopropanolamine and deionized water are weighed in a molar ratio of 1:1:1.2:1.5:50. The pseudoboehmite is added to a mixture of phosphoric acid (concentration 80wt%), diisopropanolamine and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 are added. After stirring, KH-570 is added, wherein the molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-570 is 1:1.5:1.2. The mixture is stirred at 30°C until a uniform gel is obtained. The gel is sealed in a stainless steel autoclave and crystallized at 150°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 700°C for 1h in a muffle furnace to obtain Ru-Mo isomorphously substituted SSZ-13.

[0047] (2) Alkali modifier modification: Lithium hydroxide is dissolved in deionized water to form a solution, and the isomorphously substituted SSZ-13 molecular sieve is immersed in the solution while the solution is refluxed, and then filtered, washed, and dried to obtain an alkali-modified catalyst precursor; wherein the molar ratio of lithium hydroxide, deionized water, and KH-570 in step (1) is 3:7:1; the immersion temperature is 70°C, and the refluxing time is 10h.

[0048] (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 20:1, adjusted to pH=12 with ammonia water, heated to a reduction temperature of 70°C, reduced for 50min, and then centrifuged, filtered, washed, and dried to obtain catalyst product C3.

[0049] Example 4:

[0050] (1) Preparation of Ru-Mo isomorphously substituted SSZ-13 molecular sieve: KH-570, pseudoboehmite, phosphoric acid, diisopropanolamine, and deionized water are weighed in a molar ratio of 1:1:1.2:1.5:50. The pseudoboehmite is added to a mixture of phosphoric acid (concentration 80wt%), diisopropanolamine, and deionized water, and then hydrous ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 are added. After stirring uniformly, KH-570 is added, wherein the molar ratio of hydrous ruthenium trichloride, Mo(NO3)3, and KH-570 is 1:1:0.8. The mixture is stirred thoroughly 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, filtered, washed with 80°C distilled water until the pH value is constant, and dried at 100°C. The product is calcined at 300°C for 1h in a muffle furnace to obtain Ru-Mo isomorphously substituted SSZ-13.

[0051] (2) Alkali modifier modification: Lithium hydroxide is dissolved in deionized water to form a solution, and the isomorphously substituted SSZ-13 molecular sieve is immersed in the solution while the solution is refluxed, and then filtered, washed, and dried to obtain an alkali-modified catalyst precursor; wherein the molar ratio of lithium hydroxide, deionized water, and KH-570 in step (1) is 3:7:1; the immersion temperature is 70°C, and the refluxing time is 10h.

[0052] (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 20:1, adjusted to pH=12 with ammonia water, heated to a reduction temperature of 70°C, reduced for 50min, and then centrifuged, filtered, washed, and dried to obtain catalyst product C3.

[0053] Example 5:

[0054] (1) Ru-Mo isomorphous substitution SSZ-13 molecular sieve preparation: KH-570, pseudoboehmite, phosphoric acid, diisopropanolamine and deionized water were weighed in a molar ratio of 1:1:0.5:1:50. The pseudoboehmite was added to the mixture of phosphoric acid (concentration 80wt%), diisopropanolamine and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 were added. After stirring, KH-570 was added, wherein the molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-570 was 1:0.8:0.5. 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 90°C for 5h. After complete crystallization, the product was centrifuged and filtered, washed with 80°C distilled water until the pH value was constant, dried at 100°C, and calcined at 200°C for 1h in a muffle furnace to obtain Ru-Mo isomorphous substitution SSZ-13.

[0055] (2) Alkali metal modifier modification: lithium hydroxide was dissolved in deionized water to form a solution, and the isomorphously substituted SSZ-13 molecular sieve was immersed in the solution while the solution was refluxed. Then the catalyst precursor was obtained by filtering, washing and drying. The molar ratio of lithium hydroxide, deionized water and KH-570 in step (1) was 3:2:1. The immersion temperature was 40°C and the refluxing time was 10h.

[0056] (3) Catalyst activation: the lithium hydroxide modified catalyst precursor was immersed in an aqueous hydrazine hydrate solution (hydrazine hydrate content 10wt%), wherein the molar ratio of hydrazine hydrate to ruthenium trichloride was 8:1. The pH value was adjusted to 7 with ammonia water, and the reduction temperature was heated to 40°C. The catalyst product C5 was obtained by reduction for 50min, centrifugal filtration, washing and drying.

[0057] Example 6:

[0058] (1) Ru-Mo isomorphous substitution SSZ-13 molecular sieve preparation: KH-570, pseudoboehmite, phosphoric acid, diisopropanolamine and deionized water were weighed in a molar ratio of 1:2:2:1.5:50. The pseudoboehmite was added to the mixture of phosphoric acid (concentration 80wt%), diisopropanolamine and deionized water, and then hydrated ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 were added. After stirring, KH-570 was added, wherein the molar ratio of hydrated ruthenium trichloride, Mo(NO3)3 and KH-570 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 180°C for 5h. After complete crystallization, the product was centrifuged and filtered, washed with 80°C distilled water until the pH value was constant, dried at 100°C, and calcined at 800°C for 1h in a muffle furnace to obtain Ru-Mo isomorphous substitution SSZ-13.

[0059] (2) Alkali modifier modification: Lithium hydroxide is dissolved in deionized water to form a solution, and the isomorphously substituted SSZ-13 molecular sieve is immersed in the solution, and the solution is refluxed, and then filtered, washed and dried to obtain an alkali modified catalyst precursor; wherein the molar ratio of lithium hydroxide, deionized water and KH-570 in step (1) is 5:10:1; the immersion temperature is 80°C, and the refluxing time is 10h.

[0060] (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 25:1, adjusted to pH = 12 with ammonia water, heated to a reduction temperature of 80°C, reduced for 50min, centrifuged, filtered, washed and dried to obtain catalyst product C6.

[0061] Example 7:

[0062] A commercially available Ru metal loaded Ru / Al2O3 catalyst with a loading of 5wt% is purchased and recorded as catalyst C7.

[0063] Example 8:

[0064] (1) Preparation of Ru-Mo isomorphously substituted SSZ-13 molecular sieve: KH-570, pseudo-boehmite, phosphoric acid, diisopropanolamine and deionized water are weighed according to the molar ratio of 1:1:1.2:1.5:50. The pseudo-boehmite is added to the mixture of phosphoric acid (concentration 80wt%), diisopropanolamine and deionized water, and then hydrous ruthenium trichloride (ruthenium content 43wt%) and Mo(NO3)3 are added, and after stirring uniformly, KH-570 is added, wherein the molar ratio of hydrous ruthenium trichloride, Mo(NO3)3 and KH-570 is 1:1:0.8; the gel is fully stirred at 30°C until a uniform gel is obtained, the gel is sealed in a stainless steel autoclave, crystallized at 100°C for 5h, the product is centrifuged and filtered, washed with 80°C distilled water until the pH value is constant, and dried at 100°C, and then calcined at 300°C in a muffle furnace for 1h to obtain Ru-Mo isomorphously substituted SSZ-13.

[0065] (2) The isomorphously substituted SSZ-13 molecular sieve is immersed in a deionized water solution, and the solution is refluxed, and then filtered, washed and dried to obtain a catalyst precursor; wherein the molar ratio of deionized water to KH-570 in step (1) is 7:1; the immersion temperature is 50°C, and the refluxing time is 10h.

[0066] (3) Catalyst activation: the catalyst precursor was immersed in aqueous hydrazine hydrate solution (hydrazine hydrate content 10wt%), the molar ratio of hydrazine hydrate to ruthenium trichloride was 10:1, adjusted to pH=8 with ammonia water, heated to a reduction temperature of 50°C, reduced for 50 min, centrifuged, filtered, washed, and dried to obtain catalyst product C8.

[0067] Examples 9-16

[0068] The catalysts of Examples 1-8 were used respectively in a fixed bed to perform the hydrogenation reaction of m-phenylenediamine, and the process conditions were as follows:

[0069] The catalyst was loaded into a fixed bed reaction tube, and quartz wool was packed at both ends of the bed. Nitrogen was used to detect the airtightness, and if the airtightness was good, nitrogen and hydrogen were used for replacement three times. Hydrogen was passed through a mass flow meter, and the flow rate was 0.08h -1 . The pressure was adjusted to 6 MPa, and the reactor was controlled to heat to 110°C. After the pressure and temperature were stable, isopropyl alcohol solution of m-phenylenediamine (m-phenylenediamine mass concentration 60%) was passed into the reactor using a high-pressure constant-flow pump, and the flow rate was 1h -1 . Under these conditions, the hydrogenation reaction was carried out, and after 10h, the hydrogen was vented, and the product was separated. The product was analyzed by gas chromatography, and the reaction results are shown in Table 1.

[0070] Table 1 Reaction results of catalysts prepared in Examples 9-16 applied to m-phenylenediamine hydrogenation

[0071]

[0072]

[0073] As can be seen from Table 1, the catalytic reaction effect of catalyst C1 is the best.

[0074] Examples 17-23

[0075] Based on catalysts C1 and C8 respectively, the hydrogenation reaction process of Examples 9-16 was used to perform the continuous hydrogenation experiment of m-phenylenediamine, and the catalyst life was tested, and the results are shown in Table 2.

[0076] Table 2 Results of continuous hydrogenation experiment of m-phenylenediamine

[0077]

[0078] From Table 2, the catalyst C1 of the present application is stable for 4000h, and no obvious decrease in conversion rate and selectivity is observed, while the conversion rate and selectivity of the C8 catalyst decrease seriously after 1000h. Due to the isomorphism replacement of active metal, the synergistic effect of the promoter and the active metal, the modification of the carrier by lithium hydroxide and the selective adsorption, the catalyst of the present application has the characteristics of long service life, high selectivity, and easy separation of products.

[0079] Although the specific embodiments of the present application are described above, the description 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-cyclohexanediamine by hydrogenating m-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 and Tm, preferably Mo; and the carrier is SSZ-13 molecular sieve.

2. A method for preparing a catalyst for hydrogenating m-phenylenediamine to 1,3-cyclohexanediamine according to claim 1, comprising the following steps: (1) Preparation of SSZ-13 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 the mixture is stirred evenly before adding organosiloxane and stirring thoroughly until a uniform gel is formed. The gel is crystallized at a constant temperature, filtered, washed with water, dried and calcined to obtain isomorphous substitution of SSZ-13 molecular sieve; (2) Alkali metal modifier modification: lithium hydroxide is dissolved in deionized water to prepare a solution, isomorphously substituted SSZ-13 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-cyclohexanediamine by hydrogenating m-phenylenediamine according to claim 2, characterized in that: In the step (1), the molar ratio of ruthenium trichloride, accelerator and organosiloxane is 1:1-1.5:0.8-1.

2.

4. The method for preparing a catalyst for hydrogenating m-phenylenediamine to prepare 1,3-cyclohexanediamine 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 1:1:1.2:1.5:

50.

5. The method for preparing a catalyst for preparing 1,3-cyclohexanediamine by hydrogenating m-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-cyclohexanediamine by hydrogenating m-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-570.

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

8. The method for preparing a catalyst for preparing 1,3-cyclohexanediamine by hydrogenating m-phenylenediamine according to claim 2, characterized in that: The crystallization temperature is 100-150° C., and the crystallization time is 5 hours; the sintering temperature is 300-700° C., and the sintering time is 1 hour.

9. The method for preparing a catalyst for hydrogenating m-phenylenediamine to prepare 1,3-cyclohexanediamine 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 3:7:1; the immersion temperature in step (2) is 50-70° C., preferably 60° C.; and the reflux time is 0.5-24 h, preferably 10 h.

10. The method for preparing a catalyst for hydrogenating m-phenylenediamine to prepare 1,3-cyclohexanediamine according to claim 2, characterized in that: The molar ratio of hydrazine hydrate to ruthenium trichloride in step (3) is 10-20:1; the mass fraction of hydrazine hydrate in the hydrazine hydrate aqueous solution is 5-90%; the reduction temperature in step (3) is 20-70° C., and the reduction time is 50 minutes.

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