A Ni-Sn@C-SDB catalyst and its application and a method for catalyzing the aqueous catalytic synthesis of higher alcohols from ethanol

Abstract

The invention discloses a Ni-Sn@C-SDB catalyst and its application and a method for catalyzing the aqueous catalytic synthesis of higher alcohols from ethanol. The catalyst is prepared by ball milling a Ni-Sn bimetallic catalyst and a hydrophobic polymer SDB to obtain NiSn@C-SDB. The hydrophobic polymer is ball milled to greatly increase the hydrophobicity of the catalyst, thereby reducing the phenomenon of deactivation caused by the dehydration of the aldol condensation reaction and the water molecules in the reaction raw materials, resulting in the blockage of the catalyst internal pores, the formation of "water poisoning", and the formation of a phenomenon of deactivation. The catalyst is applied in the reaction of catalyzing the one-step synthesis of higher alcohols from aqueous ethanol, showing excellent catalytic efficiency, high reaction activity, high ethanol conversion rate, and increased selectivity for C6+ higher alcohols. The catalyst is simple to prepare, low in cost, and the reaction performance of the catalyst is improved by simple ball milling, which is more conducive to its production application. The invention belongs to the field of catalyst technology.

Description

Technical Field

[0001] The present invention relates to a catalyst, in particular to a Ni-Sn@C-SDB catalyst. The present invention also relates to the application of the Ni-Sn@C-SDB catalyst and a method for catalyzing the aqueous phase synthesis of higher alcohols from ethanol. Technical Background

[0002] At present, environmental problems are becoming increasingly serious mainly due to the excessive consumption of fossil resources. The supply of traditional energy is facing huge pressure, which has aroused people's increasing attention to renewable energy and accelerated energy transformation. Biomass is recognized as the only renewable carbon resource. The use of biomass is of great significance for sustainable alternative energy and reducing carbon emissions. Due to the long history of industrial fermentation production, ethanol extracted from biomass sugar has been identified as the most successful commercial biofuel among existing alternative biofuels, accounting for the largest share of global biofuel production and consumption. Blending ethanol into gasoline can replace pure fossil fuels, provide additional oxygen, improve combustion performance, thereby improving engine performance and reducing pollutant emissions. Although fuel ethanol has many advantages, its inherent disadvantages such as low cetane number (11), low energy density (26MJ / kg), high autoignition temperature (420℃), and high hygroscopicity have hindered its widespread application in diesel engines. Compared with ethanol, higher carbon alcohols (such as isoheptanol) have higher cetane number (≥17), higher energy density (≥32MJ / kg), lower autoignition temperature (≤345℃), lower hygroscopicity and better compatibility with traditional fuel systems, making them ideal diesel additives.

[0003] In the Guerbet coupling of low-order alcohols, the primary chain propagation reaction proceeds through a cascade of steps, including initial dehydrogenation of the alcohol to form an aldehyde, followed by aldol self-condensation / cross-condensation and dehydration, and the final hydrogenation of the unsaturated condensation product to produce a saturated higher-order alcohol. Guerbet coupling offers an atom- and step-economical strategy, leveraging abundant fuel ethanol. Research is primarily focused on coupling between isopentanol and ethanol within fuel ethanol to produce higher-carbon isomerized alcohols. Promoting aldol condensation typically requires an alkaline condensing agent and a hydrogenation / dehydrogenation metal catalyst. The aldol self-condensation / cross-condensation and dehydration in the second step of the Guerbet coupling process generate water molecules, which can enter the catalyst's internal pores, clog the reaction site, cause "water poisoning," and rapidly deactivate the catalyst. This places higher demands on the catalyst's hydrophobic properties.

[0004] Over the past few decades, heterogeneous catalysts for alcohol coupling have been extensively explored. Initially, bifunctional catalysts with acidic and basic sites (such as MgO, MgAlO, and HAP) were used to complete the alcohol coupling process. However, due to the weak catalytic activity of these catalysts, high reaction temperatures exceeding 300°C are required, which often leads to excessive side reactions such as alcohol dehydration or decomposition, reducing the yield of high alcohols (less than 20%). To address these shortcomings, the introduction of transition metal promoters with dehydrogenation functions (such as Ru, Rh, Pd, Pt, Au, Ni, and Cu) combined with homogeneous bases can also effectively accelerate the coupling reaction rate. In particular, nickel-based catalysts have been widely studied in ethanol coupling due to their low cost and ease of availability compared to precious metal catalysts.

[0005] Compared to rare precious metals such as 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. Meanwhile, although Ni-based metal catalysts have excellent catalytic activity for alcohol dehydrogenation and hydrogenation reactions, the strong CC bond cleavage ability of Ni-based monometallic catalysts can result in excessively high byproduct selectivity. Summary of the Invention

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the first object of the present invention is to propose a Ni-Sn@C-SDB catalyst. The Ni-Sn bimetallic catalyst is simply ball-milled with a hydrophobic styrene-divinylbenzene copolymer to improve the hydrophobic properties of a simple Ni-Sn carbon-coated catalyst, thereby promoting the further coupling of low-carbon alcohols to higher alcohols. The ball-milled catalyst has improved ethanol conversion rate and selectivity for C6+ alcohol products in the synthesis of higher-carbon alcohols by coupling ethanol.

[0007] A second object of the present invention is to provide a method for aqueous-phase catalytic synthesis of higher alcohols from ethanol using a Ni-Sn@C-SDB catalyst. The catalyst catalyzes the further coupling of lower alcohols to higher alcohols, and the ball-milled catalyst improves both the ethanol conversion rate and the selectivity of C6+ alcohol products in the ethanol coupling synthesis of higher alcohols.

[0008] To this end, the first technical solution provided by the present invention is as follows:

[0009] A Ni-Sn@C-SDB catalyst is prepared by ball milling using a Ni-Sn bimetallic catalyst and a hydrophobic polymer SDB;

[0010] The mass ratio of the Ni-Sn bimetallic catalyst to the hydrophobic polymer SDB is 1:(0.5-3).

[0011] The ball milling time is 3-5 hours, and the ball milling rate is 100-500 rpm; more preferably, the ball milling time is 4 hours, and the ball milling rate is 300 rpm;

[0012] Furthermore, the mass ratio of the NiSn@C catalyst and the hydrophobic polymer SDB used in ball milling is preferably 1:1.

[0013] Furthermore, the above-mentioned Ni-Sn@C-SDB catalyst, the Ni-Sn bimetallic catalyst is prepared by the following method:

[0014] 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;

[0015] The molar ratio of Ni / Sn in the nickel salt and the tin salt is (1-30):1, and the molar ratio of Ni in the nickel salt to the carbon source precursor is 1:(0.2-5);

[0016] S2, place the nickel-tin bimetallic catalyst gel precursor prepared in S1 in an inert gas atmosphere at 1-10 ° C

[0017] A controlled high-temperature self-reduction carbonization reaction is carried out at 400-700° C. at a heating rate of 1 / min for 2-4 hours to obtain a Ni-Sn bimetallic carbon-coated bimetallic catalyst.

[0018] Furthermore, the nickel salt includes nickel nitrate, nickel chloride, nickel acetate, and nickel hydroxide, preferably nickel nitrate.

[0019] Furthermore, the tin salt includes tin nitrate, tin citrate, and tin chloride, preferably tin chloride.

[0020] Furthermore, the preferred molar ratio of Ni / Sn in the nickel salt and the tin salt is 20:1.

[0021] Furthermore, the carbon source precursor is an organic compound containing C, H, and O that can complex with nickel and tin metal ions, preferably citric acid, and the molar ratio of Ni in the nickel salt to the carbon source precursor is 1:2.

[0022] Furthermore, the temperature of the controlled high-temperature self-reduction carbonization reaction is 500-600°C, and the reaction time is 2-4 hours; more preferably, the reaction time is 550°C for 2 hours.

[0023] Furthermore, the heating rate of the controlled high-temperature self-reduction carbonization reaction is 1-10°C / min. When the heating rate is controlled within this range, the average particle size of the obtained catalyst is smaller and more uniform, and more preferably 2-5°C / min.

[0024] Furthermore, the above-mentioned Ni-Sn@C-SDB catalyst and the hydrophobic polymer SDB are prepared by the following method:

[0025] S1. Styrene (St) monomer needs to be purified before use to improve the conversion rate. The steps are as follows: ① Weigh 50 mL of St into a 250 mL separatory funnel, add 30 mL of 15% NaOH solution, shake and wash, shake well and let 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, use an appropriate amount of anhydrous Na2SO4 (preferably anhydrous Na2SO4 without lumps) to dry and remove water until the liquid is transparent; ③ Distill the liquid under reduced pressure, collect the effluent, and refrigerate for later use.

[0026] S2. Commercially available benzoyl peroxide (BPO) is prone to decomposition upon prolonged storage and requires recrystallization before use: ① Slowly dissolve 6 g of BPO in 25 mL of chloroform with stirring; ② Filter the solution, drip the filtrate into an appropriate amount of methanol solution, and refrigerate and allow to stand; ③ Collect the crystals by filtration, wash with a small amount of methanol, and drain; ④ Vacuum dry at 25°C and store in a brown bottle at room temperature.

[0027] S3. Prepare a dispersion: add 1-5 parts by mass of organic matter, 0.1-0.6 parts by mass of sodium dodecylbenzenesulfonate (SDBS) and 0.1-0.6 parts by mass of cellulose ether (CE) to a three-necked flask, weigh 100-300 parts by mass of ultrapure water in a three-necked flask, stir and disperse at 75°C until clear, cool and set aside, and mark as liquid A.

[0028] S4. Prepare the oil phase: weigh 5-15 parts by mass of styrene (St) purified by S1, 5-15 parts by mass of divinylbenzene (DVB) purified by S1, 10-20 parts by mass of toluene, 10-20 parts by mass of 1,2-dichloroethane, and 5-16 parts by mass of n-heptane, mix them evenly, add 0.1-0.5 parts by mass of benzoyl peroxide (BPO) recrystallized by S2, and stir slowly until it is completely dissolved. Mark it as liquid B.

[0029] S5. Heat the dispersion prepared in S3 to 45°C in an oil bath and set aside. Under a nitrogen atmosphere, slowly add the oil phase prepared in S4, carefully controlling the stirring speed to form uniform oil droplets on the surface. Slowly raise the temperature to 88°C and react for 4 hours, using nitrogen protection throughout the process. After the pellets are formed, raise the temperature to 92°C and continue the reaction for 3 hours before ending.

[0030] S6. Washing and drying: The obtained product was washed with deionized water, ethanol, and acetone three times each in sequence, dried under vacuum at 60°C for 2 h, and then taken out and bagged, which was recorded as SDB.

[0031] It should be noted that the divinylbenzene (DVB) monomer was dried with anhydrous MgSO4 during purification, and the rest of the process was the same as S1.

[0032] Furthermore, the organic matter in step S3 is any one of polyvinyl alcohol-1799, polyvinyl alcohol-2099, polyvinyl alcohol-2499, and polyvinyl alcohol-2699.

[0033] Furthermore, in step S3, the mass ratio of the organic matter to the cellulose ether is preferably 7:1.

[0034] Furthermore, the mass ratio of sodium dodecylbenzenesulfonate and cellulose ether in step S3 is preferably 6:5.

[0035] Furthermore, the mass ratio of styrene and divinylbenzene used in step S4 is preferably 1:1.

[0036] The first technical solution provided by the second technical solution of the present invention is the application of the above-mentioned NiSn@C-SDB catalyst in the aqueous phase catalytic synthesis of higher alcohols from ethanol.

[0037] The third technical solution of the present invention provides a method for catalyzing ethanol aqueous phase catalytic synthesis of higher alcohols according to the first technical solution,

[0038] Specifically, the NiSn@C-SDB catalyst described in the third aspect is combined with alkali, ethanol, and water to form a reaction system. Under a H2 atmosphere, the initial pressure is set to 0.1-1 MPa, and the reaction is carried out at 160-230°C for 6-24 hours to synthesize higher carbon alcohols.

[0039] The mass ratio of the catalyst: base: ethanol: water is 0.15:0.88:5:5 to 0.6:0.88:5:5; more preferably, the mass ratio of NiSn@C-SDB catalyst: base: small molecule alcohol: water is 0.3:0.88:5:5.

[0040] Furthermore, the base in the reaction system is sodium hydroxide or potassium hydroxide.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] 1. The technical solution provided by this invention introduces the promoting effect of metallic Sn on the formation of higher alcohols. The inhibitory effect of metallic Sn on Ni-CO bond cleavage may inhibit the continued cleavage of the CO bond 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 metallic Sn on Ni-CO bond cleavage may be related to the formation of Ni3Sn alloys on the surface and Sn atoms located at Ni defect sites.

[0043] 2. The technical solution provided by the present invention synthesizes the NiSn@C-SDB catalyst by ball milling the prepared NiSn@C and the hydrophobic polymer SDB; the hydrophobic polymer is ball milled to greatly increase the hydrophobicity of the catalyst, thereby reducing the phenomenon of deactivation caused by dehydration of the aldol condensation reaction and clogging of the internal pores of the catalyst due to water molecules in the reaction raw materials during the reaction, forming "water poisoning".

[0044] 3. The technical solution provided by the present invention applies the prepared NiSn@C-SDB catalyst to the one-step synthesis of higher alcohols from aqueous ethanol, showing excellent catalytic efficiency, high reaction activity, high ethanol conversion rate and increased selectivity for C6+ higher alcohols.

[0045] 4. The technical solution provided by the present invention is simple to prepare the catalyst with low cost, and the reaction performance of the catalyst is improved by simple ball milling, which is more conducive to its production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 TEM image of the NiSn@C catalyst prepared in Example 1.

[0047] Figure 2 TEM image of NiSn@C-SDB after ball milling of NiSn@C catalyst and hydrophobic polymer SDB.

[0048] Figure 3 XRD patterns of NiSn@C and NiSn@C-SDB after ball milling of NiSn@C catalyst and hydrophobic polymer SDB.

[0049] Figure 4 is the contact angle of NiSn@C-SDB after ball milling of NiSn@C catalyst and hydrophobic polymer SDB.

[0050] Figure 5 This is the GC gas chromatogram of the oil phase product with a ball milling ratio of 1:1 for NiSn@C-SDB.

[0051] Specific embodiment

[0052] 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.

[0053] 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.

[0054] Example 1

[0055] This embodiment provides a Ni-Sn bimetallic catalyst, which is prepared by the following steps in sequence:

[0056] 1) Weigh 10 g of ultrapure water, 5.6 g of citric acid, 0.22 g of tin chloride, and 3.68 g of nickel nitrate, add them sequentially and stir to dissolve to form a homogeneous complex solution, stir at room temperature for 4 h, then place the resulting homogeneous solution on a 100 ° C hot plate and continue stirring at 500 rpm until the solvent evaporates to form a gel, and then transfer it to a 100 ° C oven and dry it for 36 h to obtain a Ni-Sn bimetallic catalyst precursor.

[0057] 2) The prepared Ni-Sn bimetallic catalyst precursor was placed in a tubular furnace, heated to a calcination temperature of 550°C at a heating rate of 5°C / min under a nitrogen atmosphere, and calcined at this temperature for 2 h to obtain a NiSn@C catalyst.

[0058] The NiSn@C catalyst was characterized by transmission electron microscopy (TEM). Figure 1 The catalyst boasts high loading and good dispersibility. X-ray diffraction (XRD) observations reveal the presence of a Ni3Sn alloy phase within the catalyst. However, due to the low proportion of Sn in the metal, its diffraction peak is easily submerged by the strong diffraction peak of metallic Ni. Contact angle measurements reveal that the hydrophobicity of NiSn@C is relatively small, indicating weak hydrophobicity.

[0059] Example 2

[0060] This embodiment provides a method for preparing a hydrophobic polymer styrene-divinylbenzene copolymer, which is prepared by the following methods in sequence:

[0061] Step 1) Pretreatment of styrene monomer and divinylbenzene (DVB) monomer

[0062] 1) Styrene monomer pretreatment

[0063] ① Weigh 50 mL of styrene monomer (St) into a 250 mL separatory funnel, add 30 mL of 15% NaOH solution and shake to wash, shake well, let stand to separate the layers, take the upper layer, and repeat the operation three times;

[0064] ② Wash the collected liquid with deionized water several times until it is neutral, and dry it with an appropriate amount of anhydrous Na2SO4 (preferably anhydrous Na2SO4 without lumps) until the liquid is transparent;

[0065] ③The liquid is distilled under reduced pressure at a pressure of 0.1 MPa and a temperature of 90-95°C, the effluent is collected and refrigerated for later use.

[0066] 2) Divinylbenzene (DVB) monomer pretreatment

[0067] ① Weigh 50 mL of divinylbenzene (DVB) into a 250 mL separatory funnel, add 30 mL of 15% NaOH solution and shake to wash. After shaking, let it stand to separate the layers. Take the upper layer and repeat the process three times.

[0068] ② Wash the collected liquid with deionized water three times until it is neutral, and dry it with an appropriate amount of anhydrous MgSO4 (preferably anhydrous MgSO4 without agglomeration) until the liquid is transparent;

[0069] ③The liquid was distilled under reduced pressure at a pressure of 0.1 MPa and a temperature of 125°C, and the effluent was collected and refrigerated for later use.

[0070] Step 2) Benzoyl Oxide (BPO) Pre-treatment:

[0071] ① Slowly dissolve 6g of BPO in 25mL of chloroform by stirring;

[0072] ②Filter the solution, add the filtrate dropwise into 20ml of methanol solution, and refrigerate and let stand;

[0073] ③ Collect the crystals by filtration, wash them three times with 25 ml of methanol, and drain them;

[0074] ④ Dry in a vacuum drying oven at 25℃ and 0.1MPa and store in a brown bottle at room temperature.

[0075] Step 3) Preparation of dispersion

[0076] Add 3.5 g of polyvinyl alcohol, 0.6 g of sodium dodecylbenzenesulfonate (SDBS) and 0.5 g of cellulose ether (CE) to a three-necked flask. Add 300 g of ultrapure water to the three-necked flask and stir and disperse at 75°C until clear. Cool and set aside. Label it as liquid A.

[0077] Step 4) Preparation of oil phase

[0078] Weigh 10 g of purified styrene (St), 10 g of purified divinylbenzene (DVB), 15.8 g of toluene, 12.4 g of 1,2-dichloroethane, and 11.6 g of n-heptane and mix them evenly. Add 0.2 g of recrystallized benzoyl peroxide (BPO) and slowly stir until it is completely dissolved. This is labeled as solution B.

[0079] Step 5) Heat the prepared dispersion A in an oil bath to 45°C and set aside. Slowly add the prepared dispersion B under a nitrogen atmosphere, stirring at 1000 rpm to form uniform oil droplets on the surface. Slowly raise the temperature to 88°C and react for 4 hours, using nitrogen as a protective blanket. Once pellets are formed, raise the temperature to 92°C and continue the reaction for 3 hours before termination.

[0080] Step 6) Washing and Drying: The obtained product was washed with deionized water, ethanol, and acetone three times each in sequence, dried under vacuum at 60° C. for 2 h, and then taken out and bagged, which was recorded as SDB.

[0081] Example 3

[0082] This embodiment provides a method for preparing a hydrophobic catalyst NiSn@C-SDB, which comprises ball milling the NiSn@C catalyst prepared in Example 1 and the hydrophobic polymer SDB prepared in Example 2 at a speed of 300 rpm for 4 h in a superhydrophobic mass ratio of 1:0.5 to obtain hydrophobic catalysts NiSn@C-SDB with different mixing ratios.

[0083] Example 4

[0084] This embodiment provides a method for preparing a hydrophobic catalyst NiSn@C-SDB, which comprises ball milling the NiSn@C catalyst prepared in Example 1 and the hydrophobic polymer SDB prepared in Example 2 at a speed of 300 rpm for 4 h in a superhydrophobic mass ratio of 1:1 to obtain hydrophobic catalyst NiSn@C-SDB with different mixing ratios.

[0085] Example 5

[0086] This embodiment provides a method for preparing a hydrophobic catalyst NiSn@C-SDB, which comprises ball milling the NiSn@C catalyst prepared in Example 1 and the hydrophobic polymer SDB prepared in Example 2 at a superhydrophobic mass ratio of 1:1.5 at a rotation speed of 300 rpm for 4 hours to obtain the hydrophobic catalyst NiSn@C-SDB.

[0087] Example 6

[0088] This embodiment provides a method for preparing a hydrophobic catalyst NiSn@C-SDB, which comprises ball milling the NiSn@C catalyst prepared in Example 1 and the hydrophobic polymer SDB prepared in Example 2 at a speed of 300 rpm for 4 h in a superhydrophobic mass ratio of 1:2 to obtain hydrophobic catalyst NiSn@C-SDB with different mixing ratios.

[0089] Example 7

[0090] This embodiment provides a method for preparing a hydrophobic catalyst NiSn@C-SDB, which comprises ball milling the NiSn@C catalyst prepared in Example 1 and the hydrophobic polymer SDB prepared in Example 2 at a speed of 300 rpm for 4 h in a superhydrophobic mass ratio of 1:3 to obtain hydrophobic catalysts NiSn@C-SDB with different mixing ratios.

[0091] Example 8

[0092] The hydrophobic catalyst NiSn@C-SDB prepared in different mixing ratios in Example 1 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 catalyst prepared in Example 1, 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 main product of the oil phase was C6+ higher alcohols. The catalytic activity results of the products are shown in Table 1 below.

[0093] Example 9

[0094] The hydrophobic catalyst NiSn@C-SDB prepared in different mixing ratios in Example 3 was applied to a reaction system for synthesizing higher alcohols from ethanol in an aqueous phase. The reaction conditions were: 0.225 g of the catalyst in Example 3, 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 main product of the oil phase was C6+ higher alcohols. The catalytic activity results of the products are shown in Table 1 below.

[0095] Example 10

[0096] The hydrophobic catalyst NiSn@C-SDB prepared in Example 4 with different mixing ratios was applied to the reaction system for synthesizing higher alcohols from ethanol in aqueous phase. The reaction conditions were: 0.3 g of the catalyst from Example 4, 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 product and the liquid product 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 main product of the oil phase was C6+ higher alcohols. The gas chromatogram of the oil phase product gc is shown in FIG. Figure 5 The catalytic activity results of the products are shown in Table 1 below.

[0097] Example 11

[0098] The hydrophobic catalyst NiSn@C-SDB prepared in different mixing ratios in Example 5 was applied to a reaction system for synthesizing higher alcohols from ethanol in an aqueous phase. The reaction conditions were: 0.375 g of the catalyst in Example 5, 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 main product of the oil phase was C6+ higher alcohols. The catalytic activity results of the products are shown in Table 1 below.

[0099] Example 12

[0100] The hydrophobic catalyst NiSn@C-SDB prepared in different mixing ratios in Example 6 was applied to a reaction system for synthesizing higher alcohols from ethanol in an aqueous phase. The reaction conditions were: 0.45 g of the catalyst in Example 6, 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 main product of the oil phase was C6+ higher alcohols. The catalytic activity results of the products are shown in Table 1 below.

[0101] Example 13

[0102] The hydrophobic catalyst NiSn@C-SDB prepared in different mixing ratios in Example 7 was applied to a reaction system for synthesizing higher alcohols from ethanol in an aqueous phase. The reaction conditions were: 0.6 g of the catalyst in Example 7, 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 main product of the oil phase was C6+ higher alcohols. The catalytic activity results of the products are shown in Table 1 below.

[0103] in:

[0104]

[0105] The data in Table 1 show that when the NiSn@C catalyst and hydrophobic polymer SDB were milled at a mass ratio of 1:0.5 to 1:3, the ethanol conversion, alcohol yield, and higher alcohol selectivity were all higher than those of the catalyst without ball milling. In particular, at a mass ratio of 1:1, the catalytic reaction achieved an ethanol conversion of 79.4% and a higher alcohol selectivity of 70.5%. Increasing or decreasing the ball milling ratio slightly decreased the ethanol conversion and C6+ selectivity. Furthermore, the catalyst without ball milling the hydrophobic polymer exhibited lower ethanol conversion, alcohol yield, and C6+ selectivity.

[0106] Table 1 Catalytic performance test results of hydrophobic NiSn@C-SDB catalyst

[0107] Proportion Ethanol conversion rate Carbon yield of alcohol products C6+ product selectivity 1:0 64.6 34.2 59.8 1:0.5 76.1 39.3 66.8 1:1 79.4 48.0 70.5 1:1.5 78.6 45.9 70.4 1:2 76.3 45.5 69.3 1:3 77.2 43.6 69.3

[0108] In summary, the hydrophobic NiSn@C-SDB catalyst synthesized using the present method demonstrates excellent catalytic efficiency, high reactivity, and high selectivity for high-value C6+ higher alcohols in the one-step synthesis of higher alcohols from ethanol, with selectivity exceeding 70%. Furthermore, the present method is simple to prepare and inexpensive, and the catalyst's reactivity can be modified through simple ball milling, further facilitating its production and application.

[0109] 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 Ni-Sn@C-SDB catalyst, characterized in that: It was prepared by ball milling using Ni-Sn bimetallic catalyst and hydrophobic polymer SDB; The mass ratio of the Ni-Sn bimetallic catalyst to the hydrophobic polymer SDB is 1:(0.5-3); The Ni-Sn bimetallic catalyst is prepared by the following method: A1. Dissolve nickel salt, tin salt and carbon source precursor in a solvent, stir at room temperature to form a complex to obtain a homogeneous solution, and then heat and stir to form a nickel-tin bimetallic catalyst gel precursor; The molar ratio of Ni / Sn in the nickel salt and the tin salt is (1-30):1, and the molar ratio of Ni in the nickel salt to the carbon source precursor is 1:(0.2-5); A2. The nickel-tin bimetallic catalyst gel precursor prepared in A1 is placed in an inert gas atmosphere, and subjected to a controlled high-temperature self-reduction carbonization reaction at 400-700°C at a heating rate of 1-10°C / min for 2-4 hours to obtain a Ni-Sn bimetallic carbon-coated bimetallic catalyst.

2. The Ni-Sn@C-SDB catalyst according to claim 1, characterized in that The ball milling time is 3-5 hours, and the ball milling speed is 100-500 rpm.

3. The Ni-Sn@C-SDB catalyst according to claim 1, characterized in that The nickel salt is one of nickel nitrate, nickel chloride and nickel acetate; the tin salt is one of tin nitrate, tin citrate and tin chloride.

4. The Ni-Sn@C-SDB catalyst according to claim 1, characterized in that The hydrophobic polymer SDB is prepared by the following method: S1. Refined styrene or divinylbenzene monomer; S2, recrystallized benzoyl peroxide; S3. Preparation of dispersion Add 1-5 parts by mass of organic matter, 0.1-0.6 parts by mass of sodium dodecylbenzenesulfonate and 0.1-0.6 parts by mass of cellulose ether to a three-necked flask. Add 100-300 parts by mass of ultrapure water to the three-necked flask and stir and disperse at 75°C until clear. Cool and set aside. Label this as Solution A. S4. Prepare the oil phase: Weigh 5-15 parts by mass of styrene purified by S1, 5-15 parts by mass of divinylbenzene purified by S1, 10-20 parts by mass of toluene, 10-20 parts by mass of 1,2-dichloroethane, and 5-16 parts by mass of n-heptane, mix them evenly, add 0.1-0.5 parts by mass of benzoyl peroxide recrystallized by S2, and slowly stir until it is completely dissolved. This is labeled as Solution B. S5. Heat the dispersion prepared in S3 to 45°C in an oil bath and set aside. Slowly add the oil phase prepared in S4 under a nitrogen atmosphere, paying attention to controlling the stirring speed to form uniform oil droplets on the surface. Slowly raise the temperature to 88°C and react for 4 hours, using nitrogen protection throughout the process. After the small balls are formed, raise the temperature to 92°C and continue the reaction for 3 hours before ending. S6. Washing and drying: The obtained product was washed with deionized water, ethanol, and acetone three times each in sequence, dried under vacuum at 60°C for 2 h, and then taken out and bagged, which was recorded as SDB.

5. The Ni-Sn@C-SDB catalyst according to claim 4, characterized in that The organic matter in step S3 is any one of polyvinyl alcohol-1799, polyvinyl alcohol-2099, polyvinyl alcohol-2499, and polyvinyl alcohol-2699.

6. The Ni-Sn@C-SDB catalyst according to claim 4, characterized in that The method for refining styrene monomer described in step S1 is as follows: weigh 50 mL of styrene into a separatory funnel, add 30 mL of 15% NaOH solution, shake and wash, shake well and let stand to separate the layers, take the upper layer of liquid, and repeat the operation three times; wash the collected liquid with deionized water several times until neutral, dry it with anhydrous Na2SO4 to remove water, and remove the water until the liquid is transparent; distill the dried liquid under reduced pressure, collect the effluent, and refrigerate it for later use.

7. The Ni-Sn@C-SDB catalyst according to claim 4, characterized in that The method for refining divinylbenzene monomer described in step S1 is as follows: weigh 50 mL of divinylbenzene into a separatory funnel, add 30 mL of 15% NaOH solution, shake and wash, shake well and let stand to separate the layers, take the upper layer of liquid, and repeat the operation three times; wash the collected liquid with deionized water several times until neutral, dry it with anhydrous MgSO4 to remove water, and remove the liquid until the liquid is transparent; distill the dried liquid under reduced pressure, collect the effluent, and refrigerate it for later use.

8. The Ni-Sn@C-SDB catalyst according to claim 4, characterized in that The method for recrystallizing benzoyl peroxide in step S2 is as follows: 6 g of BPO is slowly dissolved in 25 mL of chloroform with stirring; the solution is filtered, and the filtrate is dripped into an appropriate amount of methanol solution, and refrigerated and allowed to stand; the crystals are collected by filtration, washed with methanol, dried, and then vacuum-dried at 25° C. and stored in a brown bottle at room temperature.

9. The Ni-Sn@C-SDB catalyst according to claim 1 is used for catalyzing the aqueous phase catalytic synthesis of higher alcohols from ethanol.

10. A method for synthesizing higher alcohols by ethanol aqueous phase catalysis, characterized in that: The method includes the following steps in sequence: The Ni-Sn@C-SDB catalyst according to claim 1 is combined with a base, ethanol, and water to form a reaction system, and the reaction is carried out at 160-230 ° C for 6-24 hours under a H2 atmosphere at an initial pressure of 0.1-1 MPa to synthesize higher carbon alcohols; The mass ratio of the catalyst: alkali: ethanol: water is 0.15:0.88:5:5 to 0.6:0.88:5:5.

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