Superhydrophobic catalyst for catalyzing ethanol-water coupling and its preparation method and application

Abstract

The invention discloses a super-hydrophobic catalyst for catalyzing ethanol aqueous phase coupling and its preparation method and application, it is intended to provide a kind of catalyst that can effectively improve the hydrophobicity of simple nickel-based catalyst, promote lower-carbon alcohol to be further coupled to higher alcohol, the super-hydrophobic catalyst obtained after ball milling has improved the ethanol conversion rate of ethanol coupling synthesis of higher-carbon alcohols and the selectivity of C6+ alcohol products, its technical scheme is that nickel-based catalyst and super-hydrophobic polymer polydivinylbenzene are added to ball mill according to mass ratio of 1:0-4, and the super-hydrophobic catalyst obtained by ball milling for 2-10 hours at a rotating speed of 200-600rpm is provided; the catalyst ethanol aqueous phase synthesizes higher-carbon alcohols; belongs to the field of synthesis technology.

Description

Technical Field

[0001] The present invention relates to a super hydrophobic catalyst, specifically, a plurality of Ni-based catalysts coupled with a hydrophobic polymer PDVB. The present invention also relates to the application of the super hydrophobic catalyst and a method for catalyzing the aqueous phase synthesis of higher alcohols from ethanol. Technical Background

[0002] In response to increasingly severe environmental challenges, particularly the strained energy supply caused by overconsumption of fossil resources, the exploration and application of renewable energy has become a global focus, accelerating the transformation of the energy structure. As a unique renewable carbon resource, biomass plays a significant role in sustainable energy substitution and carbon emission reduction. Thanks to the maturity of industrial fermentation technology, ethanol derived from biomass sugars has been successfully commercialized, becoming a leader in the biofuel field and occupying a dominant market position.

[0003] The blending of ethanol into gasoline not only reduces dependence on pure fossil fuels but also optimizes the combustion process by providing additional oxygen, improving engine efficiency and effectively reducing pollutant emissions. However, certain inherent properties of ethanol, such as its low cetane number, low energy density, and high auto-ignition temperature, limit its widespread use in diesel engines. In contrast, higher carbon alcohols (such as isoheptanol) are considered more ideal diesel additive candidates due to their higher cetane number, energy density, lower auto-ignition temperature, and good compatibility with traditional fuel systems.

[0004] For many years, researchers have been committed to developing efficient heterogeneous catalysts to optimize the Guerbet coupling reaction. Initially, some progress was made using catalysts with acid-base dual functions (such as MgO, MgAlO, etc.), but the high reaction temperature and the resulting side reactions limited their application. Subsequently, the introduction of transition metals (such as Ni, Cu, etc.) as promoters, combined with homogeneous bases, significantly improved the reaction rate. In particular, Ni-based catalysts have received widespread attention in the field of ethanol coupling due to their low cost and excellent catalytic activity.

[0005] Compared to expensive precious metal catalysts, Ni-based non-precious metal catalysts not only reduce costs but also improve economic benefits. However, while Ni-based monometallic catalysts promote alcohol dehydrogenation and hydrogenation, they are also prone to causing C-C bond cleavage, increasing the formation of by-products. To this end, researchers are exploring ways to optimize the performance of Ni-based catalysts and improve their selectivity and stability by constructing bimetallic or multimetallic catalysts, manipulating catalyst structure, and adding additives.

[0006] The Guerbet coupling process for converting low-order alcohols to higher-order alcohols involves a complex cascade of reactions, including alcohol dehydrogenation, aldol condensation and dehydration, and hydrogenation and saturation of the final product. The key to promoting aldol condensation in this process lies in selecting a suitable catalyst, while also addressing the issue of catalyst "poisoning" caused by the generation of water molecules, which places higher demands on the catalyst's hydrophobic properties. Summary of the Invention

[0007] In order to overcome the deficiencies of the above-mentioned prior art, the first object of the present invention is to propose a new super-hydrophobic catalyst formed by coupling a Ni-based catalyst with a hydrophobic polymer PDVB. This series of catalysts improves the hydrophobic properties of the simple nickel-based catalyst by simple ball milling with hydrophobic polydivinylbenzene, promotes the further coupling of low-carbon alcohols to higher alcohols, and the super-hydrophobic catalyst obtained after ball milling has improved the ethanol conversion rate and the selectivity of C6+ alcohol products for the synthesis of higher-carbon alcohols by ethanol coupling.

[0008] A second object of the present invention is to provide a method for synthesizing higher carbon alcohols from ethanol in an aqueous phase using a nickel-based PDVB catalyst. The catalyst catalyzes the further coupling of lower carbon alcohols to higher alcohols, and the ball-milled catalyst improves the ethanol conversion rate and the selectivity of C6+ alcohol products in the ethanol coupling synthesis of higher carbon alcohols.

[0009] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0010] To this end, the first technical solution provided by the present invention is as follows:

[0011] A super-hydrophobic catalyst for catalyzing ethanol-water coupling is obtained by adding a nickel-based catalyst and a super-hydrophobic polymer polydivinylbenzene into a ball mill at a mass ratio of 1:0-4, and ball milling the mixture at a rotation speed of 200-600 rpm for 2-10 hours.

[0012] Compared to rare precious metals like Pd and Ru, the transition metal Ni is abundant and exhibits excellent catalytic performance in many typical reactions. Therefore, Ni-based non-precious metal catalysts can effectively replace precious metal catalysts, reducing catalyst costs and improving economic benefits. Furthermore, Ni-based metal catalysts exhibit excellent catalytic activity for alcohol dehydrogenation and hydrogenation reactions.

[0013] Furthermore, in the above-mentioned super-hydrophobic catalyst for catalyzing the coupling of ethanol with water, the mass ratio of the nickel-based catalyst to the super-hydrophobic polymer polydivinylbenzene is 1:1.

[0014] Furthermore, the above-mentioned super-hydrophobic catalyst for catalyzing the aqueous phase coupling of ethanol, the nickel-based catalyst is prepared by the following method:

[0015] S1, dissolving the nickel salt and the carbon source precursor in a solvent, stirring at room temperature to form a complex to obtain a homogeneous solution, and then heating and stirring to form a nickel-based catalyst gel precursor;

[0016] The molar ratio of the nickel salt to the carbon source is 1:2;

[0017] S2. The nickel-based catalyst gel precursor of S1 is placed in an inert gas atmosphere and subjected to a controlled high-temperature self-reduction carbonization reaction at 550° C. for 2 hours to obtain a nickel-coated carbon Ni@CA catalyst.

[0018] Furthermore, the above-mentioned super-hydrophobic catalyst for catalyzing the aqueous phase coupling of ethanol, the nickel-based catalyst is prepared by the following method:

[0019] S1, dissolving nickel salt, tin salt and carbon source precursor in a solvent, stirring at room temperature to form a complex to obtain a homogeneous solution, and then heating and stirring to form a nickel-tin bimetallic catalyst gel precursor;

[0020] The molar ratio of Ni / Sn in the nickel salt and the tin salt is 20:1, and the molar ratio of Ni in the nickel salt to the carbon source precursor is 1:2;

[0021] S2. The nickel-tin bimetallic catalyst gel precursor of S1 was placed in an inert gas atmosphere and subjected to a controlled high-temperature self-reduction carbonization reaction at 550°C for 2 hours to obtain a nickel-tin-coated carbon NiSn@CA bimetallic-based catalyst.

[0022] Although Ni-based metal catalysts possess excellent catalytic activity for alcohol dehydrogenation and hydrogenation, the strong C-C bond cleavage ability of Ni-based monometallic catalysts can result in excessive selectivity for byproducts. Regarding the catalytic role of Sn metal, relevant studies have shown that in aqueous-phase reforming of oxygenated hydrocarbons, the introduction of Sn into Ni catalysts can significantly weaken Ni's C-O bond cleavage activity, thereby suppressing the methane produced by hydrogenolysis and promoting the formation of dehydrogenated products. We have also observed a similar effect of Sn metal on the formation of higher alcohols. This inhibitory effect of Sn metal on Ni C-O bond cleavage may inhibit the continued C-O bond cleavage of the aldehyde intermediate formed by dehydrogenation. The released aldehyde intermediate further promotes the subsequent aldol condensation process, achieving carbon chain growth. This inhibitory effect of Sn metal on Ni C-O bond cleavage may be related to the formation of Sn atoms located at Ni defect sites and the formation of Ni3Sn alloys on the surface.

[0023] Furthermore, the above-mentioned super-hydrophobic catalyst for catalyzing the aqueous phase coupling of ethanol, the nickel-based catalyst is prepared by the following method:

[0024] S1. Dissolve nickel salt, carbon source precursor, and L-cysteine ​​in deionized water and stir until completely dissolved; evaporate the mixture at 80°C to gradually gel, and then dry it at 100°C until completely dry;

[0025] S2, placing the nickel-based catalyst gel precursor of S1 in an inert gas atmosphere at 550°C for a controlled high-temperature self-reduction carbonization reaction for 2 hours to obtain a nickel-coated carbon-sulfur Ni@CS catalyst;

[0026] The molar ratio of Ni in the nickel salt to the molar ratio of S in L-cysteine ​​is 30:1; the molar ratio of Ni in the nickel salt to the carbon source precursor is 1:2.

[0027] Furthermore, in the above-mentioned super-hydrophobic catalyst for catalyzing the coupling of ethanol with water, the nickel salt includes nickel nitrate, nickel chloride, nickel acetate, and nickel hydroxide, preferably nickel nitrate; the tin salt includes tin nitrate, tin citrate, and tin chloride, preferably tin chloride; and the carbon source is citric acid.

[0028] Furthermore, the above-mentioned super hydrophobic catalyst for catalyzing the coupling of ethanol into water, the polydivinylbenzene is prepared by the following method: 10g of purified divinylbenzene is stirred in 50g of solvent N,N-dimethylformamide at room temperature for 1h, then transferred to an autoclave, and heat treated at 100°C for 12h. The obtained solid is washed with methanol and dried at 100°C overnight to obtain polydivinylbenzene.

[0029] The second technical solution of the present invention is that the super-hydrophobic catalyst is used to catalyze the coupling synthesis of higher alcohols in ethanol water phase.

[0030] The third technical solution of the present invention is a method for synthesizing higher alcohols from ethanol in an aqueous phase using a super-hydrophobic nickel-based catalyst, wherein the super-hydrophobic catalyst described in the first technical solution is used in a reaction system with a base, ethanol, and water. Under an H2 atmosphere, the initial pressure is set to 0.1 MPa, and the reaction is carried out at 230°C for 12 hours to synthesize higher alcohols.

[0031] Furthermore, in the above-mentioned method of synthesizing higher alcohols from ethanol in aqueous phase using a superhydrophobic nickel-based catalyst, the mass ratio of superhydrophobic catalyst: base: ethanol: water is 0.3:0.88:5:5; the base can be sodium hydroxide or potassium hydroxide.

[0032] The reaction of synthesizing higher carbon alcohols from ethanol in aqueous phase follows the Guerbet reaction principle, and the reaction steps can generally be divided into: (1) ethanol undergoes catalytic dehydrogenation reaction at the metal active center; (2) the aldehyde intermediates formed by dehydrogenation undergo aldol condensation under the action of base / acid; (3) after the aldol condensation forms a higher carbon chain, the higher carbon chain is catalyzed by hydrogenation at the metal active center to form the desired higher carbon chain alcohol product.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] The technical solution provided by the present invention synthesizes a super-hydrophobic nickel-based catalyst by ball milling the nickel-based catalyst and hydrophobic polymer PDVB prepared; The hydrophobic degree of the catalyst is greatly increased by ball milling the hydrophobic polymer, reducing the water molecules in the aldol condensation reaction dehydration and the reaction raw materials causing the catalyst internal pores to be blocked during the reaction, forming a "water poisoning" situation and causing the phenomenon of deactivation. The technical solution provided by the present invention applies the various super-hydrophobic catalysts prepared in the reaction of catalyzing aqueous ethanol one-step synthesis of higher alcohols, showing excellent catalytic efficiency, higher reaction activity, higher ethanol conversion and selectivity to C6+ higher alcohols are also increased. The technical solution provided by the present invention has simple catalyst preparation and low cost, improves the reaction performance of the catalyst by simple ball milling, and is more conducive to its production application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the contact angle of nickel-based NiSn@CA catalyst and superhydrophobic polymer PDVB.

[0036] Figure 2 Oil phase gas chromatograms of nickel-based NiSn@CA catalyst and superhydrophobic nickel-based catalyst NiSn@CA-PDVB.

[0037] Specific embodiment

[0038] The following is a further description of specific embodiments of the present invention. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0039] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental raw materials used in the following examples are commercially available unless otherwise specified.

[0040] Example 1

[0041] This example provides a method for synthesizing a hydrophobic polymer polydivinylbenzene (PDVB), which is prepared by the following steps:

[0042] Divinylbenzene (DVB) monomer needs to be purified before use to improve the conversion rate. The steps are as follows: ① Weigh DVB into a separatory funnel, add NaOH solution and shake to wash, shake well and let it stand to separate the layers, take the upper layer of liquid, and repeat the operation three times; ② Wash the collected liquid with deionized water several times until neutral, dry it with an appropriate amount of anhydrous Mg2SO4 to remove water, and wait until the liquid is transparent; ③ Distill the liquid under reduced pressure, collect the effluent, and refrigerate it for later use.

[0043] 10 g of purified divinylbenzene was stirred in 50 g of N,N-dimethylformamide (DMF) solvent at room temperature for 1 h, then transferred to an autoclave and heat-treated at 100°C for 12 h. The obtained solid was washed with methanol and dried at 100°C overnight to obtain polydivinylbenzene.

[0044] Example 2

[0045] This example provides a method for synthesizing superhydrophobic Ni@CA-PDVB.

[0046] The nickel-based catalyst Ni@CA and the hydrophobic polymer PDVB prepared in Example 1 were ball-milled at a speed of 300 rpm for 4 h in a superhydrophobic mass ratio of 1:1 to obtain a superhydrophobic nickel-based Ni@CA-PDVB catalyst.

[0047] The nickel-based catalyst Ni@CA is prepared by the following method:

[0048] S1, dissolving 3.68g nickel nitrate and 5.6g citric acid carbon source in 10g deionized water, stirring at room temperature for 4h to form a complex to obtain a homogeneous solution, and then heating to 100°C and stirring to form a nickel-based catalyst gel precursor;

[0049] S2. The nickel-based catalyst gel precursor of S1 is placed in an inert gas atmosphere and subjected to a controlled high-temperature self-reduction carbonization reaction at 550° C. for 2 hours to obtain a nickel-coated carbon Ni@CA catalyst.

[0050] Example 3

[0051] The nickel-based Ni@CA catalyst prepared in Example 2 was applied to a reaction system for synthesizing higher alcohols from ethanol in an aqueous phase. The reaction conditions were: 0.15 g of the prepared nickel-based catalyst, 0.88 g of sodium hydroxide, 5 g of ethanol, 5 g of water, an initial pressure of 0.1 MPa, and a reaction temperature of 230° C. for 12 h. After the reaction, the reactor was cooled to room temperature, and then the gaseous and liquid products were collected. The liquid products were centrifuged to obtain an oil phase, an aqueous phase, and a catalyst solid phase. The oil phase and the aqueous phase were then analyzed by gas chromatography. The catalytic activity results of the products are shown in Table 1 below.

[0052] Example 4

[0053] The superhydrophobic nickel-based Ni@CA-PDVB catalyst prepared in Example 2 was applied to the reaction system for synthesizing higher alcohols in an ethanol aqueous phase. The reaction conditions were: 0.3 g of the catalyst prepared in Example 2, 0.88 g of sodium hydroxide, 5 g of ethanol, 5 g of water, an initial pressure of 0.1 MPa, and a reaction temperature of 230° C. for 12 h. After the reaction, the reactor was cooled to room temperature, and then the gas phase product and the liquid phase product were collected. The liquid phase product was centrifuged to obtain an oil phase, an aqueous phase, and a catalyst solid phase. The oil phase and the aqueous phase were then detected and analyzed by gas chromatography. The catalytic activity results of the product are shown in Table 1 below.

[0054] Example 5

[0055] This example provides a method for synthesizing superhydrophobic NiSn@CA-PDVB.

[0056] The prepared nickel-based catalyst NiSn@CA and the hydrophobic polymer PDVB prepared in Example 1 were ball-milled at a speed of 300 rpm for 4 h in a superhydrophobic mass ratio of 1:1 to obtain a superhydrophobic nickel-based NiSn@CA-PDVB catalyst.

[0057] The NiSn@CA is prepared by the following method:

[0058] S1, 3.68g nickel nitrate, 0.22g tin tetrachloride and 5.6g citric acid carbon source were dissolved in 10g deionized water, stirred at room temperature for 4h to form a complex to obtain a homogeneous solution, and then heated to 100°C and stirred to form a nickel-tin bimetallic catalyst gel precursor;

[0059] S2. The nickel-tin bimetallic catalyst gel precursor of S1 was placed in an inert gas atmosphere and subjected to a controlled high-temperature self-reduction carbonization reaction at 550°C for 2 hours to obtain a nickel-tin-coated carbon NiSn@CA bimetallic-based catalyst.

[0060] Example 6

[0061] The nickel-based NiSn@CA catalyst prepared in Example 5 was applied to a reaction system for synthesizing higher alcohols from ethanol in an aqueous phase. The reaction conditions were: 0.15 g of the prepared nickel-based catalyst, 0.88 g of sodium hydroxide, 5 g of ethanol, 5 g of water, an initial pressure of 0.1 MPa, and a reaction temperature of 230° C. for 12 h. After the reaction, the reactor was cooled to room temperature, and then the gaseous and liquid products were collected. The liquid product was centrifuged to obtain an oil phase, an aqueous phase, and a catalyst solid phase. The oil phase and the aqueous phase were then analyzed by gas chromatography. The catalytic activity results of the products are shown in Table 1 below.

[0062] Example 7

[0063] The superhydrophobic nickel-based NiSn@CA-PDVB catalyst prepared in Example 5 was applied to the reaction system for synthesizing higher alcohols in an ethanol aqueous phase. The reaction conditions were: 0.3 g of the catalyst prepared in Example 2, 0.88 g of sodium hydroxide, 5 g of ethanol, 5 g of water, an initial pressure of 0.1 MPa, and a reaction temperature of 230° C. for 12 h. After the reaction, the reactor was cooled to room temperature, and then the gaseous and liquid products were collected. The liquid product was centrifuged to obtain an oil phase, an aqueous phase, and a catalyst solid phase. The oil phase and the aqueous phase were then detected and analyzed by gas chromatography. The catalytic activity results of the product are shown in Table 1 below.

[0064] Example 8

[0065] This example provides a method for synthesizing superhydrophobic Ni@CS-PDVB.

[0066] The prepared nickel-based catalyst Ni@CS and the hydrophobic polymer PDVB prepared in Example 1 were ball-milled at a speed of 300 rpm for 4 h in a superhydrophobic mass ratio of 1:1 to obtain a superhydrophobic nickel-based Ni@CS-PDVB catalyst.

[0067] The Ni@CS is prepared by the following method:

[0068] S1. Dissolve 6.89 g nickel nitrate, 9.13 g citric acid carbon source, and 0.096 g L-cysteine ​​in deionized water and stir until completely dissolved; evaporate the mixture at 80°C to gradually gel, and then dry it at 100°C until completely dry;

[0069] S2, placing the nickel-based catalyst gel precursor of S1 in an inert gas atmosphere at 550°C for a controlled high-temperature self-reduction carbonization reaction for 2 hours to obtain a nickel-coated carbon-sulfur Ni@CS catalyst;

[0070] Example 9

[0071] The prepared nickel-based Ni@CS catalyst was applied to a reaction system for synthesizing higher alcohols from ethanol in an aqueous phase. The reaction conditions were: 0.15 g of the prepared nickel-based catalyst, 0.88 g of sodium hydroxide, 5 g of ethanol, 5 g of water, an initial pressure of 0.1 MPa, and a reaction time of 12 h at 230°C. After the reaction, the reactor was cooled to room temperature, and then the gaseous and liquid products were collected. The liquid product was centrifuged to obtain an oil phase, an aqueous phase, and a catalyst solid phase. The oil phase and aqueous phase were then analyzed by gas chromatography. The catalytic activity results of the products are shown in Table 1 below.

[0072] Example 10

[0073] The superhydrophobic nickel-based Ni@CS-PDVB catalyst prepared in Example 8 was applied to the reaction system for synthesizing higher alcohols in an ethanol aqueous phase. The reaction conditions were: 0.3 g of the catalyst prepared in Example 2, 0.88 g of sodium hydroxide, 5 g of ethanol, 5 g of water, an initial pressure of 0.1 MPa, and a reaction temperature of 230° C. for 12 h. After the reaction, the reactor was cooled to room temperature, and then the gaseous and liquid products were collected. The liquid product was centrifuged to obtain an oil phase, an aqueous phase, and a catalyst solid phase. The oil phase and the aqueous phase were then detected and analyzed by gas chromatography. The catalytic activity results of the product are shown in Table 1 below.

[0074] in:

[0075]

[0076]

[0077]

[0078] The data in Table 1 show that simple ball milling of the nickel-based catalyst and the hydrophobic polymer PDVB significantly improved the ethanol conversion, alcohol yield, and higher alcohol selectivity compared to the unmilled catalyst. Furthermore, the ethanol conversion, alcohol carbon yield, and C6+ selectivity of the catalyst without ball milling of the hydrophobic polymer were lower.

[0079] Table 1 Catalytic performance test results of hydrophobic NiSn@C-SDB catalyst

[0080] catalyst Ethanol conversion rate Carbon yield of alcohol products C6+ product selectivity Ni@CA 67.6 36.1 50.50 Ni@CA-PDVB 76.1 45.4 58.06 NiSn@CA 74.6 48.5 59.17 NiSn@CA-PDVB 83.3 57.7 69.95 Ni@CS 93.8 67.0 73.59 Ni@CS-PDVB 98.8 79.5 80.11

[0081] In summary, it can be seen that the super-hydrophobic nickel-based catalyst synthesized using the inventive method is applied in the reaction of catalytic ethanol one-step synthesis of higher alcohols, showing excellent catalytic efficiency, higher reaction activity and the high selectivity to high-value C6+ higher carbon alcohol products, the selectivity of C6+ alcohol products can be improved to a certain degree. In addition, the raw material preparation of the present invention is simple, low cost, and the reaction performance of catalyst can be changed by simple ball milling, which is more conducive to its production application.

[0082] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations of these embodiments may be made without departing from the principles and spirit of the present invention, and the changes still fall within the scope of protection of the present invention.

Claims

1. A super-hydrophobic catalyst for catalyzing ethanol-water coupling, characterized in that, The nickel-based catalyst and super-hydrophobic polymer polydivinylbenzene are added into a ball mill according to a mass ratio of 1:0-4, and ball milled at a rotation speed of 200-600 rpm for 2-10 hours to obtain the product.

2. a kind of super hydrophobic catalyst for catalyzing ethanol water coupling according to claim 1, is characterized in that, The mass ratio of the nickel-based catalyst to the super-hydrophobic polymer polydivinylbenzene is 1:

1.

3. a kind of super hydrophobic catalyst for catalyzing ethanol water coupling according to claim 1, is characterized in that, The nickel-based catalyst is prepared by the following method: S1, dissolving the nickel salt and the carbon source precursor in a solvent, stirring at room temperature to form a complex to obtain a homogeneous solution, and then heating and stirring to form a nickel-based catalyst gel precursor; The molar ratio of the nickel salt to the carbon source is 1:2; S2. The nickel-based catalyst gel precursor of S1 is placed in an inert gas atmosphere and subjected to a controlled high-temperature self-reduction carbonization reaction at 550° C. for 2 hours to obtain a nickel-coated carbon Ni@CA catalyst.

4. a kind of super hydrophobic catalyst for catalyzing ethanol water phase coupling according to claim 1, is characterized in that, The nickel-based catalyst is prepared by the following method: S1, dissolving nickel salt, tin salt and carbon source precursor in a solvent, stirring at room temperature to form a complex to obtain a homogeneous solution, and then heating and stirring to form a nickel-tin bimetallic catalyst gel precursor; The molar ratio of Ni / Sn in the nickel salt and the tin salt is 20:1, and the molar ratio of Ni in the nickel salt to the carbon source precursor is 1:2; S2. The nickel-tin bimetallic catalyst gel precursor of S1 was placed in an inert gas atmosphere and subjected to a controlled high-temperature self-reduction carbonization reaction at 550°C for 2 hours to obtain a nickel-tin-coated carbon NiSn@CA bimetallic-based catalyst.

5. a kind of super hydrophobic catalyst for catalyzing ethanol water coupling according to claim 1, is characterized in that, The nickel-based catalyst is prepared by the following method: S1. Dissolve nickel salt, carbon source precursor, and L-cysteine ​​in deionized water and stir until completely dissolved; evaporate the mixture at 80°C to gradually gel, and then dry it at 100°C until completely dry; S2, placing the nickel-based catalyst gel precursor of S1 in an inert gas atmosphere at 550°C for a controlled high-temperature self-reduction carbonization reaction for 2 hours to obtain a nickel-coated carbon-sulfur Ni@CS catalyst; The molar ratio of Ni in the nickel salt to the molar ratio of S in L-cysteine ​​is 30:1; the molar ratio of Ni in the nickel salt to the carbon source precursor is 1:

2.

6. a kind of super hydrophobic catalyst for catalyzing ethanol water phase coupling according to claim 4, is characterized in that, The nickel salts include nickel nitrate, nickel chloride, nickel acetate and nickel hydroxide; the tin salts include tin nitrate, tin citrate and tin chloride; and the carbon source is citric acid.

7. a kind of super hydrophobic catalyst for catalyzing ethanol water phase coupling according to claim 1, is characterized in that, The super-hydrophobic polymer polydivinylbenzene is prepared by the following method: 10 g of purified divinylbenzene is stirred in 50 g of solvent N,N-dimethylformamide at room temperature for 1 hour, then transferred to an autoclave, and heat-treated at 100°C for 12 hours. The obtained solid is washed with methanol and dried at 100°C overnight to obtain the super-hydrophobic polymer polydivinylbenzene.

8. super-hydrophobic catalyst according to claim 1 is used for coupling synthesis of higher alcohols in catalytic ethanol aqueous phase.

9. A method for synthesizing higher alcohols from ethanol in aqueous phase using a super-hydrophobic catalyst, characterized in that: The super-hydrophobic catalyst according to claim 1 is used to form a reaction system with alkali, ethanol and water. Under H2 atmosphere, the initial pressure is set to 0.1 MPa and the reaction is carried out at 230 ° C for 12 hours to synthesize higher carbon alcohols.

10. the method for super-hydrophobic catalyst catalysis ethanol aqueous phase synthesis higher alcohols according to claim 9, is characterized in that, The mass ratio of superhydrophobic catalyst: alkali: ethanol: water is 0.3:0.88:5:5; the alkali is sodium hydroxide or potassium hydroxide.

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