Oil-soluble composite ionic liquid and application thereof in catalytic hydrogenation of inferior oil

Abstract

The invention discloses an oil-soluble composite ionic liquid and application thereof. The oil-soluble composite ionic liquid is composed of a tetraphenyl phosphine oxometallate ionic liquid and a tetraphenyl phosphine metal chloride ionic liquid. The preparation process of the composite ionic liquid is simple, the cost is low, the synthesis of the oil-soluble composite ionic liquid can be realized only through ion exchange, neutralization reaction and physical mixing, and the method can provide a new design thought and industrial application for developing an efficient, stable and low-cost hydrogenation catalyst.

Description

Technical Field

[0001] This invention relates to the field of hydrogenation catalysis technology for inferior oils, specifically to a method for preparing and applying an oil-soluble composite ionic liquid for hydrogenation of inferior oils. Background Technology

[0002] In the early 20th century, the petrochemical industry experienced rapid development, with processed products finding widespread application. However, the petrochemical industry currently faces two major challenges: the limitation of crude oil reserves and the treatment of residual oil from production processes. Regarding the depletion of crude oil reserves, the development and application of renewable energy have received widespread attention. The treatment of residual oil from production processes, however, is limited by technology and cost, resulting in poor continuous processing capacity, high catalyst usage, and poor final oil quality. Therefore, developing efficient, stable, widely applicable, and low-cost hydrogenation catalysts is an effective way to solve these problems.

[0003] Inferior oil mainly refers to the high-boiling-point mixture remaining after extraction, purification, and refining processes in the petrochemical industry. It possesses extremely high viscosity and a pungent odor, and its main components are high-molecular-weight hydrocarbons. Improper storage and handling can severely burden the environment. Among existing technologies, suspended-bed hydrogenation technology is a feasible method for treating inferior oil and improving its quality. This is a crucial means of converting inferior oil into liquid fuels and other chemical products, and the key lies in the hydrogenation catalyst used.

[0004] Despite the significant efforts and progress made by researchers in the chemical industry, the design and construction of efficient and stable hydrogenation catalysts remain a core challenge in the catalytic conversion of inferior oil in suspended bed catalytic converters. Typical suspended bed hydrogenation technologies abroad, such as the solid powder catalyst developed by BP, the nanoscale iron-based catalyst developed by UOP, and the solid powder catalyst developed by INTEVEP, offer advantages such as strong feedstock adaptability, efficient coke suppression, and multi-stage catalytic hydrogenation. However, they require demanding reaction conditions, often necessitating high reaction temperatures and pressures, resulting in high energy and hydrogen consumption. Therefore, developing a low-cost, stable, widely applicable, and highly effective catalyst for the hydrogenation of inferior oil holds great promise for future applications. Summary of the Invention

[0005] This invention addresses the problems of poor stability, high cost, narrow applicability, and cumbersome synthesis routes of existing hydrogenation catalysts by providing a novel, highly efficient oil-soluble composite ionic liquid. Its preparation method is simple, can be scaled up, and exhibits good hydrogenation activity and stability in inferior oils.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: One of the objectives of this invention is to protect an oil-soluble composite ionic liquid, which is composed of a tetraphenylphosphine metal oxoacid ionic liquid and a tetraphenylphosphine metal chloride ionic liquid.

[0007] Furthermore, the atomic ratio of the metal in the tetraphenylphosphine metal oxyacid salt ionic liquid to the tetraphenylphosphine metal chloride ionic liquid is 0.1~10.

[0008] Furthermore, the preparation of the tetraphenylphosphine metal oxometalate ionic liquid includes the following steps: 1) Using methanol as the mobile phase, tetraphenylphosphine chloride is ion-exchanged through a strong base anion exchange resin, and the liquid is collected to obtain a tetraphenylphosphine hydroxide methanol solution. 2) After adding a metal oxo acid to the obtained tetraphenylphosphine hydroxide methanol solution for neutralization reaction, the solvent is removed by rotary evaporation and then dried to obtain a tetraphenylphosphine metal oxo acid salt ionic liquid.

[0009] Furthermore, the strong base anion exchange resin includes one or more of Amberjet 4000Cl, AmberliteIRA900Cl, Amberjet UP4000, Amberjet 4500(OH), IMAC HP555, and AmberliteFPA90Cl.

[0010] Furthermore, the exchange capacity of the strong base anion exchange resin is 1 to 10 times the molar amount of tetraphenylphosphine chloride, and the mobile phase with pH ≥ 8 is collected.

[0011] Furthermore, the metal oxoacid includes one or two of molybdic acid, tungstic acid, etc. When two are used, the ratio of metal atoms is 0.01-100.

[0012] Furthermore, the amount of the metal oxoacid is calculated based on a 1:1 molar ratio of protonated hydrogen to hydroxide ions in the tetraphenylphosphine hydroxide methanol solution.

[0013] Furthermore, the neutralization reaction is carried out at a temperature of 25-65°C for a time of 1-48 hours.

[0014] Furthermore, the temperature of the rotary evaporation is 30-80°C.

[0015] Furthermore, the drying temperature is 60~120 ℃, and the time is 6~24 h.

[0016] Furthermore, the tetraphenylphosphine metal chloride ionic liquid is prepared by mixing tetraphenylphosphine chloride and a metal chloride and heating and stirring until a homogeneous liquid is formed.

[0017] Furthermore, the metal chloride includes one or more of CuCl2, FeCl3, CoCl2, NiCl2, etc. When two are used, the ratio of metal atoms is 0.01-100.

[0018] Furthermore, the molar ratio of the metal chloride to tetraphenylphosphine chloride used is 1 to 10.

[0019] Furthermore, the heating temperature range is 80~160℃.

[0020] Another objective of this invention is to protect the application of the oil-soluble composite ionic liquid in the catalytic hydrogenation of inferior oils.

[0021] Furthermore, its application method involves generating a multi-metal sulfide catalyst in situ from the oil-soluble composite ionic liquid in a hydrogenation reactor under the conditions of inferior oil and sulfur source, and then using it for the catalytic hydrogenation of inferior oil.

[0022] Furthermore, the hydrogenation reaction device used is a suspended bed hydrogenation reactor.

[0023] Furthermore, the inferior oil includes one or more of the following: medium-temperature coal tar, vacuum residue, and atmospheric residue.

[0024] Furthermore, the amount of the inferior oil used is calculated based on a mass ratio of 0.01% to 20% of the metal in the oil-soluble composite ionic liquid.

[0025] Furthermore, the sulfur source includes one or more of sublimed sulfur, thiourea, dimethyl sulfide, etc., and its amount is calculated based on the molar ratio of the sulfur element contained therein to the metal in the metal oxoacid used in the oil-soluble composite ionic liquid being 1-30.

[0026] Furthermore, the hydrogen pressure during the reaction is 0~15 MPa, the reaction temperature is 300~450 ℃, the stirring speed is 300~1200 r / min, the reaction time is 1~24 h, and the hydrogen-to-oil ratio is 0~2000.

[0027] The technical solution of the present invention has the following advantages: (1) The method for preparing oil-soluble composite ionic liquid proposed in this invention can highly disperse the active components in the reaction system. Through the strong interaction between metals and metal sulfides, the activity and stability of the catalyst can be greatly improved, thereby solving the problems of poor stability, complex synthesis process and low activity of existing hydrogenation catalysts. This provides a new design idea for developing efficient, stable and low-cost hydrogenation catalysts.

[0028] (2) The oil-soluble composite ionic liquid prepared by this invention can achieve efficient hydrogenation of different inferior oils after sulfidation. Specifically, the oil-soluble composite ionic liquid prepared by this invention can achieve hydrogenation of aliphatic and aromatic oils to different degrees and depths after in-situ sulfidation. The polymetallic sulfide catalyst generated in-situ using the oil-soluble composite ionic liquid prepared by this invention can achieve a conversion rate of over 50% for inferior oils and a selectivity of over 60% for gasoline and diesel. In addition, the structure and combination of the oil-soluble composite ionic liquid are highly designable, and this preparation method can be extended to the hydrogenation process of different inferior oils. Detailed Implementation

[0029] The preparation and application of an oil-soluble composite ionic liquid includes the following steps: 1) Dissolve tetraphenylphosphine chloride in a certain amount of methanol, perform ion exchange through a strong base anion exchange resin, use methanol as the mobile phase, collect the liquid, and obtain a tetraphenylphosphine hydroxide methanol solution. 2) With a molar ratio of proton hydrogen in the metal oxoacid to hydroxide ions in the tetraphenylphosphine hydroxide methanol solution of 1:1, the metal oxoacid is added to the obtained tetraphenylphosphine hydroxide methanol solution, and the neutralization reaction is carried out at 25~65℃ for 1~48 h. Then, the solvent is removed by rotary evaporation at 30~80℃, and then dried at 60~120℃ for 6~24 h to obtain the tetraphenylphosphine metal oxoacid ionic liquid. 3) Mix the metal chloride with tetraphenylphosphine chloride at a molar ratio of 1 to 10, and heat and stir at 80 to 160 °C until a homogeneous liquid is formed to obtain a tetraphenylphosphine metal chloride ionic liquid; 4) In application, the obtained tetraphenylphosphonic metal oxo acid salt ionic liquid is mixed with tetraphenylphosphonic metal chloride salt ionic liquid to form an oil-soluble composite ionic liquid, and added as a catalyst precursor to a suspended bed hydrogenation reactor. Under the condition of the presence of inferior oil and sulfur source, it generates a polymetallic sulfide catalyst in situ, and is used for the catalytic hydrogenation of inferior oil.

[0030] The strong-base anion exchange resin includes one or more of Amberjet 4000Cl, AmberliteIRA900Cl, Amberjet UP4000, Amberjet 4500(OH), IMAC HP555, and Amberlite FPA90Cl. The metal oxoacid includes one or two of molybdic acid and tungstic acid. The metal chloride includes one or more of CuCl2, FeCl3, CoCl2, and NiCl2. The inferior oil includes one or more of medium-temperature coal tar, vacuum residue, and atmospheric residue, and its dosage is calculated based on a mass ratio of 0.01% to 20% of the metal in the oil-soluble composite ionic liquid. The sulfur source includes one or more of sublimed sulfur, thiourea, and dimethyl sulfide, and its dosage is calculated based on a molar ratio of sulfur to the metal in the tetraphenylmetal oxoacid phosphonate ionic liquid of 1-30. The hydrogen pressure during the reaction is 0~15 MPa, the reaction temperature is 300~450 ℃, the stirring speed is 300~1200 r / min, the reaction time is 1~24 h, and the hydrogen-to-oil ratio is 0~2000.

[0031] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The present invention will be described in detail below through specific embodiments.

[0033] Example 1: Preparation of an oil-soluble composite ionic liquid and its application in the hydrogenation of medium-temperature coal tar (wherein, the catalyst precursor is only a tetraphenylmolybdate phosphine salt ionic liquid, and the atomic ratio of sulfur to molybdenum is 20): (1) Measure 300 mL of strong base anion exchange resin (Amberlite IRA900 Cl), rinse it with deionized water, activate it with sodium hydroxide aqueous solution, rinse it with deionized water until neutral, and finally replace the mobile phase with methanol; weigh 37.5 g of tetraphenylphosphine chloride and dissolve it in 150 mL of methanol, and use methanol as the mobile phase. Pass the tetraphenylphosphine chloride methanol solution through the anion exchange resin and collect the mobile phase with pH≥8 to obtain the tetraphenylphosphine hydroxide methanol solution. (2) Using phenolphthalein as an indicator, the concentration of the tetraphenylphosphine hydroxide methanol solution was determined with 0.1 mol / L hydrochloric acid solution, and the content of tetraphenylphosphine hydroxide was determined to be 0.1128 g / g. Then, 7.2 g of molybdic acid was weighed and added to 280.9 g of tetraphenylphosphine hydroxide methanol solution, and stirred at room temperature for 12 h. The reaction solution became a transparent liquid. Then, the reaction solution was placed in a rotary evaporator and evaporated to dryness at 70 °C. Then, it was dried in a vacuum oven at 80 °C for 12 h to obtain tetraphenylphosphine molybdate ionic liquid. (3) Weigh 0.5055 g of tetraphenylphosphine molybdate ionic liquid, 0.3864 g of sublimed sulfur powder, and 40 g of medium-temperature coal tar into a 150 mL suspended bed high-pressure reactor. Seal the reactor and turn on the stirrer (stirring speed 600 r / min). Purge the air from the reactor with high-purity H2 and pressurize to 8 MPa. Heat the reactor to 400 ℃ at a rate of 5 ℃ / min and react for 5 h. After the reactor cools to room temperature, place the reaction solution in an automatic distillation apparatus to separate and characterize the product.

[0034] The results showed that the conversion rate of medium-temperature coal tar was 49.2%, and the selectivity for gasoline and diesel was 58.3%.

[0035] Example 2: Preparation of an oil-soluble composite ionic liquid and its application in the hydrogenation of medium-temperature coal tar (wherein, the catalyst precursor is only tetraphenylphosphine cobalt chloride ionic liquid (2:1), and the atomic ratio of sulfur to cobalt is 60): (1) Weigh 75.0 g tetraphenylphosphine chloride and 13.0 g cobalt dichloride into a 250 mL round-bottom flask, heat to 140 °C and stir until the reaction solution is a clear liquid to obtain tetraphenylphosphine cobalt chloride ionic liquid (2:1). (2) Weigh 0.8632 g of tetraphenylphosphine cobalt chloride ionic liquid (2:1), 1.8876 g of sublimed sulfur powder, and 40 g of medium-temperature coal tar into a 150 mL suspended bed high-pressure reactor. Seal the reactor and start stirring (stirring speed 600 r / min). Introduce high-purity H2 to remove air from the reactor and pressurize to 8 MPa. Increase the temperature to 400 ℃ at a rate of 5 ℃ / min and react for 5 h. After the reactor cools to room temperature, place the reaction solution in an automatic distillation apparatus to separate and characterize the product.

[0036] The results showed that the conversion rate of medium-temperature coal tar was 3.9%, and the selectivity for gasoline and diesel was 89.2%.

[0037] Example 3: Preparation of an oil-soluble composite ionic liquid and its application in the hydrogenation of medium-temperature coal tar (wherein, the atomic ratio of cobalt to molybdenum is 1 / 3, and the atomic ratio of sulfur to molybdenum is 20): (1) Measure 300 mL of strong base anion exchange resin (Amberlite IRA900 Cl), rinse it with deionized water, activate it with sodium hydroxide aqueous solution, rinse it with deionized water until neutral, and finally replace the mobile phase with methanol; weigh 37.5 g of tetraphenylphosphine chloride and dissolve it in 150 mL of methanol, and use methanol as the mobile phase. Pass the tetraphenylphosphine chloride methanol solution through the anion exchange resin and collect the mobile phase with pH≥8 to obtain the tetraphenylphosphine hydroxide methanol solution. (2) Using phenolphthalein as an indicator, the concentration of the tetraphenylphosphine hydroxide methanol solution was standardized with 0.1 mol / L hydrochloric acid solution, and the content of tetraphenylphosphine hydroxide was determined to be 0.1136 g / g. Then, 7.3 g of molybdic acid was weighed and added to 282.6 g of tetraphenylphosphine hydroxide methanol solution. The mixture was stirred at room temperature for 12 h, and the reaction solution became a transparent liquid. The reaction solution was then placed in a rotary evaporator and evaporated to dryness at 70 °C. It was then dried in a vacuum oven at 80 °C for 12 h to obtain tetraphenylphosphine molybdate ionic liquid. (3) Weigh 75.0 g of tetraphenylphosphine chloride and 13.0 g of cobalt dichloride into a 250 mL round-bottom flask, heat to 140 °C and stir until the reaction solution is a clear liquid to obtain tetraphenylphosphine cobalt chloride ionic liquid (2:1). (4) Weigh 0.4196 g of tetraphenylphosphine molybdate ionic liquid, 0.1467 g of tetraphenylphosphine cobalt chloride ionic liquid (2:1), 0.3208 g of sublimed sulfur powder, and 40 g of medium-temperature coal tar into a 150 mL suspended bed high-pressure reactor. Seal the reactor and turn on the stirrer (stirring speed 600 r / min). Introduce high-purity H2 to remove air from the reactor and pressurize to 8 MPa. Increase the temperature to 400 ℃ at a rate of 5 ℃ / min and react for 5 h. After the reactor cools to room temperature, place the reaction solution in an automatic distillation apparatus to separate and characterize the product.

[0038] The results showed that the conversion rate of medium-temperature coal tar was 59.6%, and the selectivity for gasoline and diesel was 62.8%.

[0039] Example 4: Preparation of an oil-soluble composite ionic liquid and its application in the hydrogenation of medium-temperature coal tar (wherein, the atomic ratio of cobalt to molybdenum + tungsten is 1 / 3, the atomic ratio of molybdenum to tungsten is 1, and the atomic ratio of sulfur to molybdenum + tungsten is 20): (1) Measure 300 mL of strong base anion exchange resin (Amberlite IRA900 Cl), rinse it with deionized water, activate it with sodium hydroxide aqueous solution, rinse it with deionized water until neutral, and finally replace the mobile phase with methanol; weigh 37.5 g of tetraphenylphosphine chloride and dissolve it in 150 mL of methanol, and use methanol as the mobile phase. Pass the tetraphenylphosphine chloride methanol solution through the anion exchange resin and collect the mobile phase with pH≥8 to obtain the tetraphenylphosphine hydroxide methanol solution. (2) Using phenolphthalein as an indicator, the concentration of the tetraphenylphosphine hydroxide methanol solution was determined with 0.1 mol / L hydrochloric acid solution, and the content of tetraphenylphosphine hydroxide was determined to be 0.1101 g / g. Then, 3.6 g of molybdic acid and 5.6 g of tungstic acid were weighed and added to 293.6 g of tetraphenylphosphine hydroxide methanol solution. The mixture was stirred at room temperature for 12 h, and the reaction solution became a transparent liquid. The reaction solution was then placed in a rotary evaporator and evaporated to dryness at 70 °C. It was then dried in a vacuum oven at 80 °C for 12 h to obtain tetraphenylmolybdic tungstate phosphine salt ionic liquid. (3) Weigh 75.0 g of tetraphenylphosphine chloride and 13.0 g of cobalt dichloride into a 250 mL round-bottom flask, heat to 140 °C and stir until the reaction solution is a clear liquid to obtain tetraphenylphosphine cobalt chloride ionic liquid (2:1). (4) Weigh 0.2451 g of tetraphenylmolybdate phosphonate ionic liquid, 0.0814 g of tetraphenylphosphine cobalt chloride ionic liquid (2:1), 0.1777 g of sublimed sulfur powder, and 40 g of medium-temperature coal tar into a 150 mL suspended bed high-pressure reactor. Seal the reactor and turn on the stirrer (stirring speed 600 r / min). Introduce high-purity H2 to remove air from the reactor and pressurize to 8 MPa. Increase the temperature to 400 ℃ at a rate of 5 ℃ / min and react for 5 h. After the reactor cools to room temperature, place the reaction solution in an automatic distillation apparatus to separate and characterize the product.

[0040] The results showed that the conversion rate of medium-temperature coal tar was 51.2%, and the selectivity for gasoline and diesel was 65.4%.

[0041] Example 5: Preparation of an oil-soluble composite ionic liquid and its application in the hydrogenation of medium-temperature coal tar (wherein, the atomic ratio of cobalt + nickel to molybdenum is 1 / 3, the atomic ratio of cobalt + nickel is 1, and the atomic ratio of sulfur to molybdenum is 20): (1) Measure 300 mL of strong base anion exchange resin (Amberlite IRA900 Cl), rinse it with deionized water, activate it with sodium hydroxide aqueous solution, rinse it with deionized water until neutral, and finally replace the mobile phase with methanol; weigh 37.5 g of tetraphenylphosphine chloride and dissolve it in 150 mL of methanol, and use methanol as the mobile phase. Pass the tetraphenylphosphine chloride methanol solution through the anion exchange resin and collect the mobile phase with pH≥8 to obtain the tetraphenylphosphine hydroxide methanol solution. (2) Using phenolphthalein as an indicator, the concentration of the tetraphenylphosphine hydroxide methanol solution was standardized with 0.1 mol / L hydrochloric acid solution, and the content of tetraphenylphosphine hydroxide was determined to be 0.1122 g / g. Then, 7.5 g of molybdic acid was weighed and added to 293.7 g of tetraphenylphosphine hydroxide methanol solution, and stirred at room temperature for 12 h. The reaction solution became a transparent liquid. Then, the reaction solution was placed in a rotary evaporator and evaporated to dryness at 70 °C. Then, it was dried in a vacuum oven at 80 °C for 12 h to obtain tetraphenylmolybdate phosphine salt ionic liquid. (3) Weigh 75.0 g tetraphenylphosphine chloride, 6.5 g cobalt dichloride, and 6.5 g nickel dichloride into a 250 mL round-bottom flask, heat to 140 °C and stir until the reaction solution is a clear liquid to obtain tetraphenylphosphine cobalt nickel dichloride ionic liquid (2:(0.5+0.5)).

[0042] (4) Weigh 0.4197 g of tetraphenylphosphine molybdate ionic liquid, 0.1471 g of tetraphenylphosphine cobalt nickel chloride ionic liquid (2:(0.5+0.5)), 0.3208 g of sublimed sulfur powder, and 40 g of medium-temperature coal tar into a 150 mL suspended bed high-pressure reactor. Seal the reactor and turn on the stirrer (stirring speed 600 r / min). Introduce high-purity H2 to remove air from the reactor and pressurize to 8 MPa. Increase the temperature to 400 ℃ at a rate of 5 ℃ / min and react for 5 h. After the reactor cools to room temperature, place the reaction solution in an automatic distillation apparatus to separate and characterize the product.

[0043] The results showed that the conversion rate of medium-temperature coal tar was 60.7%, and the selectivity for gasoline and diesel was 73.1%.

[0044] Example 6: Preparation of an oil-soluble composite ionic liquid and its application in the hydrogenation of extra-heavy oil residue (wherein the atomic ratio of cobalt to molybdenum is 1 / 3, and the atomic ratio of sulfur to molybdenum is 20): (1) Measure 300 mL of strong base anion exchange resin (Amberlite IRA900 Cl), rinse it with deionized water, activate it with sodium hydroxide aqueous solution, rinse it with deionized water until neutral, and finally replace the mobile phase with methanol; weigh 37.5 g of tetraphenylphosphine chloride and dissolve it in 150 mL of methanol, and use methanol as the mobile phase. Pass the tetraphenylphosphine chloride methanol solution through the anion exchange resin and collect the mobile phase with pH≥8 to obtain the tetraphenylphosphine hydroxide methanol solution. (2) Using phenolphthalein as an indicator, the concentration of the tetraphenylphosphine hydroxide methanol solution was standardized with 0.1 mol / L hydrochloric acid solution, and the content of tetraphenylphosphine hydroxide was determined to be 0.1132 g / g. Then, 7.4 g of molybdic acid was weighed and added to 287.8 g of tetraphenylphosphine hydroxide methanol solution, and stirred at room temperature for 12 h. The reaction solution became a transparent liquid. Then, the reaction solution was placed in a rotary evaporator and evaporated to dryness at 70 °C. Then, it was dried in a vacuum oven at 80 °C for 12 h to obtain tetraphenylphosphine molybdate ionic liquid. (3) Weigh 75.0 g of tetraphenylphosphine chloride and 13.0 g of cobalt dichloride into a 250 mL round-bottom flask, heat to 140 °C and stir until the reaction solution is a clear liquid to obtain tetraphenylphosphine cobalt chloride ionic liquid (2:1). (4) Weigh 0.4190 g of tetraphenylphosphine molybdate ionic liquid, 0.1465 g of tetraphenylphosphine cobalt chloride ionic liquid (2:1), 0.3208 g of sublimed sulfur powder, and 40 g of extra-heavy oil residue into a 150 mL suspended bed high-pressure reactor. Seal the reactor and turn on the stirrer (stirring speed 600 r / min). Introduce high-purity H2 to remove air from the reactor and pressurize to 8 MPa. Increase the temperature to 400 ℃ at a rate of 5 ℃ / min and react for 5 h. After the reactor cools to room temperature, place the reaction solution in an automatic distillation apparatus to separate and characterize the product.

[0045] The results showed that the conversion rate of extra-heavy oil to atmospheric residue was 66.4%, and the selectivity for gasoline and diesel was 75.6%.

[0046] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. An oil-soluble composite ionic liquid, characterized in that, The oil-soluble composite ionic liquid is composed of a tetraphenylphosphine metal oxo acid salt ionic liquid and a tetraphenylphosphine metal chloride salt ionic liquid with a metal atomic ratio of 0.1 to 10.

2. The oil-soluble composite ionic liquid according to claim 1, characterized in that, The preparation of the tetraphenyl metal oxophosphate ionic liquid includes the following steps: 1) Using methanol as the mobile phase, tetraphenylphosphine chloride is ion-exchanged through a strong base anion exchange resin, and the liquid is collected to obtain a tetraphenylphosphine hydroxide methanol solution. 2) After adding a metal oxo acid to the obtained tetraphenylphosphine hydroxide methanol solution for neutralization reaction, the solvent is removed by rotary evaporation and then dried to obtain a tetraphenylphosphine metal oxo acid salt ionic liquid.

3. The oil-soluble composite ionic liquid according to claim 2, characterized in that, The strong base anion exchange resin includes one or more of Amberjet 4000Cl, Amberlite IRA900Cl, Amberjet UP4000, Amberjet 4500(OH), IMAC HP555, and Amberlite FPA90Cl; the metal oxoacid includes one or two of molybdic acid and tungstic acid, and the amount of the metal oxoacid is calculated based on a 1:1 molar ratio of proton hydrogen in the metal oxoacid to hydroxide ions in the tetraphenylphosphine hydroxide methanol solution; the neutralization reaction is carried out at a temperature of 25~65℃ for 1~48 h.

4. The oil-soluble composite ionic liquid according to claim 1, characterized in that, The tetraphenylphosphine metal chloride ionic liquid is prepared by mixing tetraphenylphosphine chloride and a metal chloride, heating and stirring until a homogeneous liquid is formed.

5. The oil-soluble composite ionic liquid according to claim 4, characterized in that, The metal chloride includes one or more of CuCl2, FeCl3, CoCl2, and NiCl2, and its molar ratio with tetraphenylphosphine chloride is 1 to 10; the heating temperature range is 80 to 160°C.

6. The application of the oil-soluble composite ionic liquid as described in claim 1 in the catalytic hydrogenation of inferior oil, characterized in that, In a hydrogenation reactor, under the conditions of inferior oil and sulfur source, the oil-soluble composite ionic liquid is used to generate a polymetallic sulfide catalyst in situ, which is then used for the catalytic hydrogenation of inferior oil.

7. The application according to claim 6, characterized in that, The hydrogenation reaction apparatus used is a suspended bed hydrogenation reactor.

8. The application according to claim 6, characterized in that, The inferior oil includes one or more of medium-temperature coal tar, vacuum residue, and extra-heavy atmospheric residue; its dosage is calculated based on a mass ratio of 0.01% to 20% of the metal in the oil-soluble composite ionic liquid.

9. The application according to claim 6, characterized in that, The sulfur source includes one or more of sublimed sulfur, thiourea, and dimethyl sulfide, and its dosage is calculated based on a molar ratio of sulfur element to metal in the metal oxoacid used in the oil-soluble composite ionic liquid of 1-30.

10. The application according to claim 6, characterized in that, The hydrogen pressure during the reaction is 0~15 MPa, the reaction temperature is 300~450 ℃, the stirring speed is 300~1200 r / min, the reaction time is 1~24 h, and the hydrogen-to-oil ratio is 0~2000.