Preparation method of ruthenium-based catalyst and application of ruthenium-based catalyst in squalene hydrogenation reaction

Abstract

The invention discloses a method for preparing a carbon-supported ruthenium-based bimetallic catalyst by an impregnation method. The method is used for hydrogenating squalene obtained by extracting multicoloured leaves into squalane. The catalyst takes activated carbon as a carrier, and a main metal ruthenium and auxiliary metal elements (such as iron, manganese, cobalt, copper, cerium and the like) are loaded through an impregnation method. The preparation process comprises the following steps: (1) pretreatment of an activated carbon carrier: pretreating the activated carbon carrier by adopting a chemical modification method, and adjusting the number of oxygen-containing functional groups and surface acid sites on the surface of the activated carbon; (2) dipping treatment: dipping the pretreated catalyst into a solution containing metal salt for 12 hours; (3) roasting treatment: putting the metal-loaded carrier into a tubular furnace, roasting in a nitrogen atmosphere, heating to 300-600 DEG C, and maintaining for 3 hours; and (4) reduction treatment: putting the roasted catalyst into the tubular furnace again, carrying out reduction treatment in a hydrogen atmosphere, heating to 300 DEG C, and maintaining for 3 hours to obtain the catalyst. The catalyst shows high activity, high selectivity and good long-term stability in a squalene hydrogenation reaction, the yield of squalene can be effectively improved, the production cost is reduced, and the catalyst has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to a method for hydrogenating squalene extracted from Panicum scabra leaves using a ruthenium-on-carbon catalyst. This technology is widely used in the fields of biomedicine, chemical industry, and energy. Background Art

[0002] Squalene is an important natural active substance with numerous bioactive properties and applications, including antioxidant and immune-enhancing properties. It is widely found in plants and animals, such as marine fish and olive oil, and is widely used in cosmetics, health supplements, and pharmaceuticals. However, the extraction and hydrogenation of squalene suffer from low efficiency and high costs. Traditionally, squalene is primarily derived from shark liver oil, but overfishing has led to a sharp decline in shark populations, necessitating the search for sustainable alternative sources. In recent years, due to limited marine resources and environmental protection requirements, the extraction of squalene from plants has become a research hotspot. Paniculata variegata leaves are a key source of squalene, being rich in squalene and its derivatives. As an olefin with unsaturated carbon-carbon double bonds, squalene is easily oxidized by air. Hydrogenation can convert squalene into more stable saturated alkanes. Existing hydrogenation catalysts are mostly based on precious metals, such as platinum and palladium, which offer good catalytic performance but are relatively expensive. Ruthenium-on-carbon catalysts, due to their excellent catalytic performance and stability, have gained widespread application in organic synthesis. Ruthenium-on-carbon catalysts improve catalytic efficiency and anti-loss properties by embedding ruthenium particles on a carbon carrier, enabling them to exhibit excellent performance in olefin hydrogenation reactions. Summary of the Invention

[0003] This invention provides a technology for producing squalane by hydrogenating squalene using a ruthenium-on-carbon catalyst. The goal is to provide a green, environmentally friendly, efficient, and economical technology for extracting and hydrogenating squalene, reducing environmental burdens and improving resource utilization efficiency.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A method for preparing a carbon-supported ruthenium-based bimetallic catalyst comprises the following steps:

[0006] (1) Pretreatment of activated carbon carrier: Chemical modification is used to pretreat activated carbon to change the type and number of functional groups on the surface of activated carbon. Chemical modification can change the hydrophilicity / hydrophobicity and acidity of activated carbon and improve the adsorption performance of activated carbon carrier.

[0007] (2) Impregnation treatment: The modified activated carbon is impregnated in a solution containing the main metal Ru and the auxiliary metal. After the impregnation process is completed, it is dried to obtain an activated carbon carrier loaded with bimetallic materials.

[0008] (3) Calcination treatment: The activated carbon carrier loaded with Ru-M bimetallic was placed in a nitrogen atmosphere and heated in a tube furnace for calcination treatment;

[0009] (4) Reduction treatment: The activated carbon carrier loaded with Ru-M bimetallic was placed in a hydrogen atmosphere and heated in a tube furnace for reduction treatment;

[0010] Preferably, the modification method in step (1) is oxidation modification or acid-base modification;

[0011] Preferably, the modification method in step (1) is to use 5wt% nitric acid solution for oxidation modification;

[0012] Preferably, the modification method in step (1) uses 5wt% sulfuric acid solution for acid-base modification;

[0013] Preferably, the oxidation modification treatment time in step (1) is 6 hours;

[0014] Preferably, the acid-base modification treatment time in step (1) is 6 hours;

[0015] Preferably, the impregnation treatment in step (2) includes a co-impregnation method and a step-by-step impregnation method; the loading amount of metal Ru is 2 wt%; the auxiliary metal includes any one of Fe, Mn, Co, Cu, and Ce;

[0016] Preferably, the calcination temperature in step (3) is 300-600° C. and the calcination time is 3 hours;

[0017] Preferably, the reduction treatment temperature in step (4) is 300° C. and the reduction treatment time is 3 h.

[0018] The beneficial effects of the above technical solution of the present invention are as follows:

[0019] 1. Chemically modify the activated carbon carrier to change the type and number of functional groups on the activated carbon surface, the hydrophilicity / hydrophobicity of the activated carbon, and adjust the surface acidity. In addition, using activated carbon as a carrier to load active metals results in high metal dispersion.

[0020] 2. The active metals of the catalyst are main metal ruthenium and auxiliary metals (Fe, Mn, Co, Cu, Ce). Ru is the main active component, which hydrogenates unsaturated carbon-carbon double bonds. The auxiliary metal plays an auxiliary role to improve product selectivity.

[0021] 3. The present invention uses ruthenium as the main active metal, which has low preparation cost, long-term stability, and can be recycled multiple times. The ruthenium-based bimetallic catalyst prepared by the present invention has the advantages of high efficiency and low by-products. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the embodiments.

[0023] Example 1

[0024] A method for preparing a co-impregnation Ru-Fe / AC catalyst comprises the following steps:

[0025] (1) Activated carbon carrier pretreatment: oxidative modification treatment was performed using a 5 wt% dilute nitric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidative pickling time of 6 h.

[0026] (2) Preparation of precursor solution: Weigh RuCl3 and FeCl3·6H2O and dissolve them in deionized water to obtain a mixed metal salt solution A, where the mass ratio of Ru to Fe in solution A is 1:1;

[0027] (3) Impregnation treatment: The activated carbon after oxidation modification was impregnated in mixed metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru-Fe;

[0028] (4) Calcination: The Ru-Fe loaded activated carbon support was placed in a nitrogen atmosphere and heated in a tube furnace for calcination; the calcination temperature was 300°C, the calcination time was 3 hours, and the heating rate was 5°C / min;

[0029] (5) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced under a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Fe / AC catalyst prepared by the co-impregnation method.

[0030] Example 2

[0031] A method for preparing a co-impregnated Ru-Fe / AC catalyst. The preparation process of Example 2 is roughly similar to that of Example 1, with the main difference being the modification method of the activated carbon support pretreatment in step (1). The specific steps are as follows:

[0032] (1) Activated carbon carrier pretreatment: The activated carbon carrier was subjected to acid treatment modification using a 5 wt% sulfuric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidation treatment pickling time of 6 h.

[0033] (2) Preparation of precursor solution: Weigh RuCl3 and FeCl3·6H2O and dissolve them in deionized water to obtain a mixed metal salt solution A, where the mass ratio of Ru to Fe in solution A is 1:1;

[0034] (3) Impregnation treatment: The activated carbon after oxidation modification was impregnated in mixed metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru-Fe;

[0035] (4) Calcination: The Ru-Fe loaded activated carbon support was placed in a nitrogen atmosphere and heated in a tube furnace for calcination; the calcination temperature was 300°C, the calcination time was 3 hours, and the heating rate was 5°C / min;

[0036] (5) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced under a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Fe / AC catalyst prepared by the co-impregnation method.

[0037] Example 3

[0038] The preparation process of Example 3 is similar to that of Example 1, with the main difference being the calcination temperature in step (4). The specific steps are as follows:

[0039] (1) Activated carbon carrier pretreatment: oxidative modification treatment was performed using a 5 wt% dilute nitric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidative acid washing time of 6 h.

[0040] (2) Preparation of precursor solution: Weigh RuCl3 and FeCl3·6H2O and dissolve them in deionized water to obtain a mixed metal salt solution A, where the mass ratio of Ru to Fe in solution A is 1:1;

[0041] (3) Impregnation treatment: The activated carbon after oxidation modification was impregnated in mixed metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru-Fe;

[0042] (4) Calcination: The Ru-Fe loaded activated carbon support was placed in a nitrogen atmosphere and heated in a tube furnace for calcination; the calcination temperature was 450°C, the calcination time was 3 hours, and the heating rate was 5°C / min;

[0043] (5) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced under a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Fe / AC catalyst prepared by the co-impregnation method.

[0044] Example 4

[0045] The preparation process of this embodiment 4 is similar to that of embodiment 1, the main difference being the calcination temperature in step (4). The specific steps are as follows:

[0046] (1) Activated carbon carrier pretreatment: oxidative modification treatment was performed using a 5 wt% dilute nitric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidative pickling time of 6 h.

[0047] (2) Preparation of precursor solution: Weigh RuCl3 and FeCl3·6H2O and dissolve them in deionized water to obtain a mixed metal salt solution A, where the mass ratio of Ru to Fe in solution A is 1:1;

[0048] (3) Impregnation treatment: The activated carbon after oxidation modification was impregnated in mixed metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru-Fe;

[0049] (4) Calcination: The Ru-Fe loaded activated carbon support was placed in a nitrogen atmosphere and heated in a tube furnace for calcination; the calcination temperature was 600°C, the calcination time was 3 hours, and the heating rate was 5°C / min;

[0050] (5) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced under a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Fe / AC catalyst prepared by the co-impregnation method.

[0051] Example 5

[0052] A step-by-step impregnation method for preparing a Ru-Fe / AC catalyst. The preparation process of Example 5 is roughly similar to that of Example 1, with the main difference being the preparation of the precursor solution in step (2). The specific steps are as follows:

[0053] (1) Activated carbon carrier pretreatment: oxidative modification treatment was performed using a 5 wt% dilute nitric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidative pickling time of 6 h.

[0054] (2) Preparation of precursor solution: Weigh RuCl3 and dissolve it in deionized water to obtain metal salt solution A; weigh FeCl3·6H2O and dissolve it in deionized water to obtain metal salt solution B; the mass ratio of Ru to Fe in solution A and solution B is 1:1;

[0055] (3) First impregnation treatment: The activated carbon after oxidation modification was impregnated in metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru;

[0056] (4) Second impregnation treatment: The Ru-loaded activated carbon support was impregnated in the metal salt solution B and immersed again at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain a Ru-Fe-loaded activated carbon support;

[0057] (5) Calcination treatment: The Ru-Fe loaded activated carbon support was placed in a nitrogen atmosphere and heated in a tube furnace for calcination treatment; the calcination temperature was 300°C, the calcination time was 3 hours, and the heating rate was 5°C / min;

[0058] (6) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced under a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Fe / AC catalyst prepared by the step-by-step impregnation method.

[0059] Example 6

[0060] A method for preparing a co-impregnation Ru-Mn / AC catalyst. The preparation process of Example 6 is roughly similar to that of Example 1, with the main difference being the type of metal salt in the precursor solution in step (2). The specific steps are as follows:

[0061] (1) Activated carbon carrier pretreatment: oxidative modification treatment was performed using a 5 wt% dilute nitric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidative acid washing time of 6 h.

[0062] (2) Preparation of precursor solution: Weigh RuCl3 and Mn(NO3)2·4H2O and dissolve them in deionized water to obtain a mixed metal salt solution A. The mass ratio of Ru to Mn in solution A is 1:1.

[0063] (3) Impregnation treatment: The activated carbon after oxidation modification was impregnated in mixed metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru-Fe;

[0064] (4) Calcination treatment: The Ru-Mn loaded activated carbon support was placed in a nitrogen atmosphere and heated in a tube furnace for calcination treatment; the calcination temperature was 450°C, the calcination time was 3 hours, and the heating rate was 5°C / min;

[0065] (5) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced in a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Mn / AC catalyst prepared by the co-impregnation method.

[0066] Example 7

[0067] A method for preparing a co-impregnation Ru-Co / AC catalyst. The preparation process of Example 7 is roughly similar to that of Example 1, with the main difference being the type of metal salt in the precursor solution in step (2). The specific steps are as follows:

[0068] (1) Activated carbon carrier pretreatment: oxidative modification treatment was performed using a 5 wt% dilute nitric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidative acid washing time of 6 h.

[0069] (2) Preparation of precursor solution: Weigh RuCl3 and CoCl2·6H2O and dissolve them in deionized water to obtain a mixed metal salt solution A, where the mass ratio of Ru to Co in solution A is 1:1;

[0070] (3) Impregnation treatment: The activated carbon after oxidation modification was impregnated in mixed metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru-Fe;

[0071] (4) Calcination: The Ru-Co loaded activated carbon support was placed in a nitrogen atmosphere and heated in a tube furnace for calcination; the calcination temperature was 450°C, the calcination time was 3 h, and the heating rate was 5°C / min;

[0072] (5) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced under a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Co / AC catalyst prepared by the co-impregnation method.

[0073] Example 8

[0074] A method for preparing a co-impregnation Ru-Cu / AC catalyst. The preparation process of Example 8 is roughly similar to that of Example 1, with the main difference being the type of metal salt in the precursor solution in step (2). The specific steps are as follows:

[0075] (1) Activated carbon carrier pretreatment: oxidative modification treatment was performed using a 5 wt% dilute nitric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidative acid washing time of 6 h.

[0076] (2) Preparation of precursor solution: Weigh RuCl3 and CuCl2·2H2O and dissolve them in deionized water to obtain a mixed metal salt solution A, where the mass ratio of Ru to Cu in solution A is 1:1;

[0077] (3) Impregnation treatment: The activated carbon after oxidation modification was impregnated in mixed metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru-Fe;

[0078] (4) Calcination: The Ru-Cu loaded activated carbon support was placed in a nitrogen atmosphere and heated in a tube furnace for calcination; the calcination temperature was 450°C, the calcination time was 3 hours, and the heating rate was 5°C / min;

[0079] (5) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced under a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Cu / AC catalyst prepared by the co-impregnation method.

[0080] Example 9

[0081] A method for preparing a co-impregnation Ru-Ce / AC catalyst. The preparation process of Example 9 is roughly similar to that of Example 1, with the main difference being the type of metal salt in the precursor solution in step (2). The specific steps are as follows:

[0082] (1) Activated carbon carrier pretreatment: oxidative modification treatment was performed using a 5 wt% dilute nitric acid solution with a carrier to solution ratio of 6 g:150 mL and an oxidative pickling time of 6 h.

[0083] (2) Preparation of precursor solution: Weigh RuCl3 and Ce(NO3)3·6H2O and dissolve them in deionized water to obtain a mixed metal salt solution A. The mass ratio of Ru to Ce in solution A is 1:1.

[0084] (3) Impregnation treatment: The activated carbon after oxidation modification was impregnated in mixed metal salt solution A at room temperature for 12 h. After the impregnation process was completed, it was dried to obtain an activated carbon support loaded with Ru-Fe;

[0085] (4) Calcination: The Ru-Ce loaded activated carbon support was placed in a nitrogen atmosphere and calcined in a tube furnace at a temperature of 450°C, a calcination time of 3 h, and a heating rate of 5°C / min.

[0086] (5) Reduction treatment: The calcined catalyst was placed in a tubular furnace again and reduced in a hydrogen atmosphere; the reduction temperature was 300°C, the calcination time was 3 h, and the heating rate was 5°C / min, thereby obtaining a Ru-Ce / AC catalyst prepared by the co-impregnation method.

[0087] 0.1g of the catalyst prepared in Example 1-9, 15g of isopropanol and 2g of squalene were weighed and added to a 40mL autoclave, purged three times with high-purity hydrogen, and finally pressurized to 2MPa and sealed to carry out catalytic hydrogenation. The initial stirring speed during the temperature rise was 200rpm, and the speed was increased to 1000rpm when heated to 180°C, and the timing was started. The reaction time was 18h. After the reaction was completed, the autoclave was cooled to room temperature, the catalyst and the reaction solution mixture and the reacted gas were collected, and the solution and gas components obtained by the catalytic hydrogenation reaction were analyzed separately using gas chromatography to calculate the conversion and selectivity. The specific results are shown in Table 1.

[0088] Table 1 Experimental results of catalytic hydrogenation of squalene on carbon-supported ruthenium-based bimetallic catalyst

[0089] Example Conversion Rate % Squalane yield / % 1 82.6 79.0 2 54.1 45.9 3 92.2 87.6 4 71.5 68.2 5 71.8 50.7 6 73.3 56.2 7 80.8 54.1 8 71.2 50.6 9 75.6 60.8

Claims

1. A method for preparing a carbon-supported ruthenium-based bimetallic catalyst, characterized in that: The following steps are involved: (1) Activated carbon carrier pretreatment: Activated carbon is pretreated by chemical modification to change the type and number of functional groups on the surface of activated carbon, the hydrophilicity / hydrophobicity of activated carbon, and the adsorption properties of the carrier; (2) Impregnation treatment: The modified activated carbon is impregnated in a solution containing the main metal Ru and the auxiliary metal. After the impregnation process is completed, it is dried to obtain an activated carbon carrier loaded with bimetallic materials. (3) Calcination treatment: The activated carbon carrier loaded with bimetallic materials is placed in a nitrogen atmosphere and heated in a tube furnace for calcination treatment; (4) Reduction treatment: The activated carbon carrier loaded with bimetallic is placed in a hydrogen atmosphere and heated in a tubular furnace for reduction treatment to obtain a loaded ruthenium-based bimetallic catalyst.

2. The method for preparing a carbon-supported ruthenium-based bimetallic catalyst according to claim 1, wherein: The chemical modification method in step (1) is any one of oxidation modification and acid-base modification. The oxidation modification method adopts a nitric acid solution with a concentration of 0 to 10 wt% for oxidation modification; the oxidation modification treatment time is 0.5 to 9 hours. The acid-base modification method adopts a sulfuric acid solution with a concentration of 0 to 10 wt% for oxidation modification; the acid-base modification treatment time is 0.5 to 9 hours.

3. The method for preparing a carbon-supported ruthenium-based bimetallic catalyst according to claim 1, wherein: In step (2), the auxiliary metal is any one of Fe, Mn, Co, Cu, and Ce; the mass fraction of the main metal Ru is 2% of the activated carbon carrier; and the mass ratio of the main metal to the auxiliary metal is 1:

1.

4. The method for preparing a carbon-supported ruthenium-based bimetallic catalyst according to claim 1, wherein: The calcination treatment temperature in step (3) is 300-600°C, the time is 0.5-6h, and the heating rate is 5°C / min.

5. The method for preparing a carbon-supported ruthenium-based bimetallic catalyst according to claim 1, wherein: The reduction treatment temperature in step (4) is 450° C., the time is 0.5 to 6 h, and the heating rate is 5° C. / min.

6. Use of a catalyst prepared by the method according to any one of claims 1 to 5, characterized in that: The catalyst is used for direct hydrogenation reaction of squalene in an aqueous phase, the reaction temperature is 160-200° C., the reaction time is 0.5-24 h, and the reaction pressure is 0.5-4 MPa.