Pretreatment method and application of aluminum oxide loaded copper oxide-rare earth metal oxide catalyst

Abstract

The invention discloses a pretreatment method and application of an aluminum oxide loaded copper oxide-rare earth metal oxide catalyst. The pretreatment method comprises the following steps: adding an aluminum oxide loaded copper oxide-rare earth metal oxide catalyst for the reaction of preparing higher alcohol from ethanol into a mixed solution of one or more of C1-C8 alcohols, dipping at 10-90 DEG C for 1-24 hours, filtering to remove redundant alcohols after dipping is completed, and drying in a drying oven at 40-200 DEG C for 1-24 hours to complete the pretreatment of the catalyst. The invention provides the application of the aluminum oxide loaded copper oxide-rare earth metal oxide catalyst treated by the pretreatment method in the reaction of preparing higher alcohol from ethanol. According to the pretreatment method disclosed by the invention, the selectivity of the product higher alcohol is remarkably improved, and the conversion rate of the ethanol is unchanged or slightly improved, so that the problem that the conversion rate and the selectivity are difficult to consider at the same time in the prior art is solved.

Description

(I) Technical field

[0001] The invention relates to a pretreatment method of an alumina-loaded copper oxide-rare earth metal oxide catalyst for a reaction of preparing higher alcohols from ethanol and an application thereof in the reaction of preparing higher alcohols from ethanol. (II) Background technology

[0002] Nowadays, governments around the world are seeking effective ways to solve environmental problems such as the global energy crisis and the greenhouse effect. Carbon-containing biomass is an important raw material for the production of clean energy and other chemicals such as renewable biomass fuels. Among them, bioethanol is the product with the largest output and the highest degree of commercialization today, and its production technology is quite mature. However, as a fuel, ethanol has problems such as low energy density, strong hygroscopicity, and corrosion of automobile engine cylinders, so it is not an ideal gasoline blending component. Compared with ethanol, n-butanol has a high energy density, is difficult to dissolve in water, and can be mixed with gasoline in a higher proportion (close to 20%), making it an ideal blending component for gasoline. Similar to butanol, higher alcohols such as hexanol and octanol can also be used as excellent fuel blending components, especially their higher cetane number, which is suitable for use as diesel additives to increase the oxygen content of diesel, and can significantly reduce particulate matter and nitrogen oxides produced during diesel combustion. In addition to being used as fuel, these higher alcohols are also important industrial solvents and synthetic raw materials, which can be used in coatings, rubber, plastics, cosmetics, fragrances and other industries.

[0003] Under mild reaction conditions, ethanol dehydrogenation coupling follows the Guerbet reaction mechanism, and the target product n-butanol undergoes four cascade reaction steps: first, ethanol molecules are dehydrogenated to produce acetaldehyde, then acetaldehyde undergoes aldol condensation to produce 3-hydroxybutyraldehyde, then 3-hydroxybutyraldehyde is dehydrated to produce crotonaldehyde, and finally crotonaldehyde is hydrogenated to produce n-butanol. The product n-butanol can further undergo Guerbet reaction to produce higher carbon alcohols (such as hexanol, 2-ethylbutanol, octanol, 2-ethylhexanol, etc.). In addition to the main reaction, ethanol will dehydrate to produce ether and ethylene, and ethanol and acetaldehyde will react to produce ethyl acetate and 1,1-diethoxyethane, etc., which is not conducive to the improvement of the selectivity of higher alcohols such as n-butanol and n-hexanol.

[0004] In the publicly published literature, Ishii and his colleagues reported for the first time the first truly homogeneous catalytic system for the conversion of ethanol to n-butanol. They prepared a noble metal iridium complex catalyst, and used phosphine as a ligand and 1,7-butadiene as a hydrogen acceptor to catalyze the upgrading of ethanol to higher alcohols in the presence of a strong base sodium ethoxide. The final ethanol conversion rate and total higher alcohol selectivity reached 41% and 90%, respectively. The alcohol dehydrogenation and aldehyde hydrogenation steps in the Guerbet reaction pathway can be achieved on the metal iridium complex, while the aldol condensation step is carried out on the strong base sodium ethoxide [Chemistry Letters, 2009, 38 (8): 838-839]. Dowson et al. prepared a series of Ru-based complex homogeneous catalysts and applied them to the ethanol to n-butanol reaction. Among them, [RuCl2 (η 6 -p-cymene)]2 as a catalyst precursor and bis(diphenylphosphino)methane as a ligand. At 423K and in an alkaline environment in the presence of sodium ethoxide, a 20.4% ethanol conversion rate and a 90% n-butanol selectivity were achieved after 4 hours of reaction [Angewandte Chemie, 2013, 52(34):9005-9008]. Although the above two catalysts show good catalytic effects, their catalyst preparation process is cumbersome. Soluble strong bases such as sodium hydroxide and sodium ethoxide are used as catalysts for the acetaldehyde aldol condensation step, which makes it difficult to separate the catalyst, the reaction time is long, and the reaction is difficult to carry out continuously, which is not conducive to industrial scale-up production. In recent years, metal-supported catalysts have been widely used in the dehydrogenation condensation of ethanol to produce higher alcohols, and have shown excellent catalytic performance. For example, He et al. reported a single-atom Ru catalyst supported by a layered Mg-Al composite oxide, and used it in the ethanol condensation reaction to produce higher alcohols. At 623K, 0.1MPa N2, WHSV=3.2h -1Under the reaction conditions, the Ru / Mg3Al1-LDO catalyst with a Ru loading of 1.04wt% exhibited an ethanol conversion rate of 29.6% and a selectivity of 82.6% for C4 and higher alcohols. The catalyst characterization results show that atomically dispersed Ru promotes the dehydrogenation of ethanol and regulates the acid-base properties of the catalyst to a certain extent, thereby further promoting the aldol condensation of acetaldehyde [Applied Catalysis B: Environmental, 2022, 309: 121271-121280]. Jordison et al. used La2O3 to modify the Ni / γ-Al2O3 catalyst in a reactor to synthesize higher alcohols from ethanol. The total selectivity of the higher alcohols obtained at 503K exceeded 85%, and the yield was as high as 38%. Under the same conditions, the total yield of higher alcohols on the Ni / γ-Al2O3 catalyst was only 26%. The CO2-TPD and NH3-TPD characterizations showed that the addition of La2O3 effectively reduced the number of acidic sites and significantly increased the number of basic sites, which not only promoted the condensation of acetaldehyde into higher alcohols, but also inhibited the formation of by-products such as ether, ethylene, and ethyl acetate [Industrial & Engineering Chemistry Research, 2015, 54(44): 10991-11000]. x / Al2O3 catalyst (MO x (rare earth metal oxides) in a fixed bed ethanol continuous catalytic conversion to synthesize higher alcohols (reaction conditions: 523K, 3MP N 2， LHSV=2mL / (h·g cat )) showed an ethanol conversion rate of 45.6% and a higher alcohol yield of 26.9%. The addition of rare earth metal oxides increases the active sites for aldol condensation, and the stability of the catalyst is also significantly improved due to the interaction between the Cu active sites and the rare earth metal oxides [CN202110593460.X; CN113443964B]. The present invention pre-treats the alumina-supported copper oxide-rare earth metal oxide catalyst by using one or more C1-C8 alcohols, introduces hydrophobic groups on the catalyst surface, promotes the condensation coupling of reaction intermediates such as acetaldehyde and butyraldehyde, thereby further improving the selectivity of higher alcohols, and since the ethanol to higher alcohol reaction generates water, the weakening of the water adsorption capacity of the hydrophobic catalyst surface is also conducive to the forward progress of the overall reaction. (III) Summary of the invention

[0005] The first technical problem to be solved by the present invention is to provide a pretreatment method for an alumina-supported copper oxide-rare earth metal oxide catalyst used in the reaction of preparing higher alcohols from ethanol.

[0006] The second technical problem of the present invention is to provide the use of the treated alumina-supported copper oxide-rare earth metal oxide catalyst in the reaction of preparing higher alcohols from ethanol.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for pretreating an alumina-supported copper oxide-rare earth metal oxide catalyst for the reaction of ethanol to produce higher alcohols. The method comprises: adding the alumina-supported copper oxide-rare earth metal oxide catalyst for the reaction of ethanol to produce higher alcohols to a mixed solution of one or more C1-C8 alcohols, impregnating at 10-90°C for 1-24h, filtering to remove excess alcohol after the impregnation, and then drying in an oven at 40-200°C for 1-24h to complete the pretreatment of the catalyst.

[0009] Preferably, the impregnation is carried out under shaking conditions.

[0010] In the present invention, the C1-C8 alcohol is selected from at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, n-pentanol, n-hexanol, n-heptanol and n-octanol.

[0011] The alumina-supported copper oxide-rare earth metal oxide catalyst for ethanol to higher alcohol reaction of the present invention comprises an alumina carrier and copper oxide and rare earth metal oxide supported on the surface thereof. The content of each component in the alumina-supported copper oxide-rare earth metal oxide catalyst is expressed in mass percentage as follows:

[0012] Alumina carrier 55%~96.5%

[0013] Copper oxide 2%~25%

[0014] Rare earth metal oxides 1.5%~20%

[0015] The rare earth metal element contained in the alumina-supported copper oxide-rare earth metal oxide catalyst is lanthanum, samarium or praseodymium.

[0016] Preferably, in the alumina-supported copper oxide-rare earth metal oxide catalyst, the molar ratio of copper oxide to rare earth metal oxide is 3:1 to 3:6.

[0017] The alumina-supported copper oxide-rare earth metal oxide catalyst of the present invention may contain other components that do not substantially affect its catalytic performance, such as a small amount of impurities introduced due to the use of commercial alumina carriers, soluble copper salts and rare earth metal salts during the preparation process.

[0018] In the present invention, the carrier alumina is in granular form, and there is no special requirement for its particle size. The particle diameter of the generally used alumina carrier is 0.2 to 5 mm. Preferably, the alumina carrier is in granular form, and the specific surface area is 180 to 450 m 2 / g, average pore diameter 1-15nm, pore volume 0.3-1.5mL / g.

[0019] The alumina-supported copper oxide-rare earth metal oxide catalyst is prepared by an impregnation method, that is, copper oxide and rare earth metal oxide precursors are loaded onto the surface of the alumina carrier by impregnation, and then the alumina carrier loaded with copper oxide and rare earth metal oxide precursors is calcined in air or an inert gas atmosphere to obtain the alumina-supported copper oxide-rare earth metal oxide catalyst. The specific preparation steps of the alumina-supported copper oxide-rare earth metal oxide catalyst of the present invention are as follows:

[0020] (1) immersing a dried alumina support in a mixed solution of copper oxide and a rare earth metal oxide precursor, shaking and mixing, and then standing for 1 to 48 hours;

[0021] (2) drying the mixture obtained in step (1) so that the precursors of copper oxide and rare earth metal oxide are evenly loaded on the inner and outer surfaces of the alumina support;

[0022] (3) placing the alumina carrier loaded with copper oxide and rare earth metal oxide precursor obtained by drying in step (2) in a muffle furnace and calcining at 300-800° C. in air or inert gas atmosphere for 0.5-24 h to obtain an alumina-loaded copper oxide-rare earth metal oxide catalyst.

[0023] In the above preparation method, the copper oxide precursor can be a soluble copper salt such as copper nitrate, copper chloride, copper acetate, copper acetylacetonate, etc. The rare earth metal oxide precursor can be a nitrate of a rare earth metal, a acetylacetonate, or a mixture of several of them. The solvent for preparing the mixed solution of the copper oxide and rare earth metal oxide precursor can be one or a mixture of any proportion of deionized water, methanol, ethanol, isopropanol, acetylacetone, chloroform, tetrahydrofuran, and N,N-dimethylformamide.

[0024] Preferably, the drying treatment in step (2) is carried out in a rotary evaporator and an oven, first drying in a rotary evaporator at 10-60°C and 0.005-0.1 MPa for 1-24 h, and then drying in an oven at 50-150°C for 1-48 h.

[0025] In a second aspect, the present invention provides use of a catalyst treated by the pretreatment method described in the first aspect in a reaction of producing higher alcohols from ethanol.

[0026] Preferably, the ethanol to higher alcohol reaction is continuously carried out in a fixed bed reactor. The catalyst pretreated with C1-C8 alcohol is in-situ reduced with ethanol before use, and the reduction conditions are: temperature of 150-300°C, pressure of normal pressure to 6.0 MPa, and liquid space velocity of ethanol of 0.5-5.0 mL / (h·g cat ), nitrogen / ethanol = 100-800:1 (volume ratio). The reaction conditions of the ethanol to higher alcohol reaction are: temperature of 200-300°C, pressure of normal pressure to 6.0 MPa, liquid space velocity of ethanol of 0.5-5.0 mL / (h·g cat ). Under this condition, the catalyst has high selectivity and yield of higher alcohols and excellent stability. The main by-products of the reaction are ether, ethyl acetate, etc., and the unreacted ethanol can be recycled.

[0027] The higher alcohols described in the present invention include C4-C10 alcohols, namely, aliphatic primary carbon alcohols such as n-butanol, 2-ethylbutanol, n-hexanol, 2-ethylhexanol, n-octanol, 2-ethyloctanol, and n-decanol.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The C1-C8 alcohol pretreatment of the alumina-supported copper oxide-rare earth metal oxide catalyst increases the hydrophobicity of the catalyst, making it easier for reaction intermediates such as acetaldehyde and butyraldehyde, which are less polar than ethanol and water, to undergo condensation coupling reactions, thereby significantly increasing the selectivity of the product higher alcohols.

[0030] (2) The reaction of ethanol to produce higher alcohols produces water at the same time as the higher alcohols are produced, and the C1-C8 alcohol pretreatment of the alumina-supported copper oxide-rare earth metal oxide catalyst increases the hydrophobicity of the catalyst, thereby pulling the reaction to the right and promoting the conversion of ethanol, so that the conversion rate of ethanol remains unchanged or slightly improved, thereby solving the problem that the existing technology is difficult to take into account both conversion rate and selectivity at the same time.

[0031] (3) The catalyst preparation and pretreatment methods of the present invention are simple and reliable, with low production costs. At the same time, when applied to the reaction of ethanol to higher alcohols, a fixed bed continuous reaction process is adopted, and thus it is suitable for industrial application. (IV) Description of the drawings

[0032] Figure 1Schematic diagram of a fixed-bed reaction device for the dehydrogenation condensation of ethanol to produce higher alcohols: 1-hydrogen cylinder, 2-nitrogen cylinder, 3-raw material bottle, 4-high-pressure constant flow pump, 5-three-way valve, 6-pressure reducing valve, 7-stop valve, 8-mass flow meter, 9-check valve, 10-reaction tube, 11-reaction furnace, 12-condenser, 13 and 14-condensate inlet and outlet, 15-filter, 16-back pressure valve, 17-product collection tank, 18-catalyst bed. (V) Specific implementation methods

[0033] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0034] If no specific conditions are specified in the examples of the present invention, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be obtained by conventional technical means or purchased commercially.

[0035] The specific surface area of ​​the alumina carrier used in the embodiment of the present invention is 289m 2 / g, pore volume 0.61cm 3 / g, average pore size 7.2nm.

[0036] Example 1

[0037] Weigh 0.4562g Cu(NO3)2·3H2O and 0.4769g La(NO3)3·6H2O and add them to 8mL anhydrous ethanol. After they are completely dissolved and mixed evenly, add 2g alumina carrier and shake and impregnate for 4h. The above mixture is rotary evaporated on a rotary evaporator at 60℃ and 0.07MPa for 1h, and the solid matter after rotary evaporation is placed in an oven at 110℃ for 4h, and finally calcined in a muffle furnace at 500℃ in air atmosphere for 3h to obtain alumina-supported copper oxide-rare earth metal oxide catalyst. Take 2g of the calcined catalyst and add it to 20ml methanol and heat and shake it at 30℃ for 5h. After the shaking is completed, filter to remove excess methanol, and then bake it in an oven at 110℃ for 4h to obtain catalyst A.

[0038] Example 2

[0039] The preparation method of catalyst B is the same as that of Example 1, but the calcined catalyst is added to 20 ml of ethanol and heated and shaken at 40°C for 5 h, then filtered and dried in an oven at 110°C for 4 h.

[0040] Example 3

[0041] The preparation method of catalyst C is the same as that of Example 1, but the calcined catalyst is added to 20 ml of n-propanol and heated and shaken at 50°C for 5 h, then filtered and dried in an oven at 110°C for 4 h.

[0042] Example 4

[0043] Catalyst D was prepared in the same manner as in Example 1, except that the calcined catalyst was added to 20 ml of isopropanol and heated and shaken at 50°C for 5 h, then filtered and dried in an oven at 110°C for 4 h.

[0044] Example 5

[0045] The preparation method of catalyst E is the same as that of Example 1, but the calcined catalyst is added to 20 ml of n-butanol and heated and shaken at 60°C for 5 h, then filtered and dried in an oven at 120°C for 4 h.

[0046] Example 6

[0047] Catalyst F was prepared in the same manner as in Example 1, except that the calcined catalyst was added to 20 ml of sec-butyl alcohol and heated and shaken at 70°C for 5 h, then filtered and dried in an oven at 120°C for 4 h.

[0048] Example 7

[0049] The preparation method of catalyst G is the same as that of Example 1, but the calcined catalyst is added to 20 ml of n-pentanol and heated and shaken at 80°C for 5 h, then filtered and dried in an oven at 140°C for 4 h.

[0050] Example 8

[0051] The preparation method of catalyst H is the same as that of Example 1, but the calcined catalyst is added to 20 ml of n-hexanol and heated and shaken at 85°C for 5 h, then filtered and dried in an oven at 160°C for 4 h.

[0052] Example 9

[0053] The preparation method of catalyst I is the same as that of Example 1, but the calcined catalyst is added to 20 ml of n-heptanol and heated and shaken at 85° C. for 5 h, then filtered and dried in an oven at 180° C. for 4 h.

[0054] Example 10

[0055] The preparation method of catalyst J is the same as that of Example 1, but the calcined catalyst is added to 20 ml of n-octanol and heated and shaken at 85°C for 5 h, then filtered and dried in an oven at 200°C for 4 h.

[0056] Embodiment 11

[0057] The preparation method of catalyst K is the same as that of Example 1, but the calcined catalyst is added to a mixture of 10 ml of ethanol and 10 ml of n-butanol and heated and shaken at 60°C for 5 h, then filtered and dried in an oven at 120°C for 4 h.

[0058] Example 12

[0059] The preparation method of catalyst L is the same as that of Example 1, but the calcined catalyst is added to a mixture of 10 ml of ethanol and 10 ml of n-hexanol and heated and shaken at 60°C for 5 h, then filtered and dried in an oven at 160°C for 4 h.

[0060] Example 13

[0061] The preparation method of catalyst M is the same as that of Example 1, except that 0.4080 g of samarium nitrate (Sm(NO3)3·6H2O) is used to replace 0.4769 g of lanthanum nitrate (La(NO3)3·6H2O), and the calcined catalyst is added to 20 ml of n-butanol and heated and shaken at 60°C for 5 h, then filtered and dried in an oven at 120°C for 4 h.

[0062] Embodiment 14

[0063] The preparation method of catalyst N is the same as that of Example 1, except that 0.3993 g of praseodymium nitrate (Pr(NO3)3·6H2O) is used to replace 0.4769 g of lanthanum nitrate (La(NO3)3·6H2O), and the calcined catalyst is added to 20 ml of n-butanol and heated and shaken at 60°C for 5 h, then filtered and dried in an oven at 120°C for 4 h.

[0064] Comparative Example 1

[0065] The preparation method of catalyst O is the same as that of Example 1, but the calcined catalyst is not subjected to alcohol pretreatment.

[0066] Comparative Example 2

[0067] The preparation method of Catalyst P is the same as that of Comparative Example 1, except that 0.4080 g of samarium nitrate (Sm(NO3)3·6H2O) is used to replace 0.4769 g of lanthanum nitrate (La(NO3)3·6H2O).

[0068] Comparative Example 3

[0069] The preparation method of catalyst Q is the same as that of comparative example 1, except that 0.3993 g of praseodymium nitrate (Pr(NO3)3·6H2O) is used to replace 0.4769 g of lanthanum nitrate (La(NO3)3·6H2O).

[0070] Embodiment 15

[0071] Reaction device such as Figure 1 As shown, the catalysts A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P and Q prepared in the above examples and comparative examples were respectively loaded into the reaction tube of the fixed bed reactor, and the catalysts were first subjected to ethanol in-situ reduction treatment. The reduction conditions were set as follows: temperature 250° C., normal pressure, and liquid space velocity of ethanol 1.0 mL / (h·g cat), nitrogen / ethanol = 250:1 (volume ratio), and then a fixed bed continuous catalytic synthesis of higher alcohols was carried out. The reaction conditions were set as follows: 250°C, 1MP, liquid space velocity 1mL / (h·g cat ), and the results are shown in Table 1.

[0072] Table 1 Reaction performance of different catalysts in the continuous catalytic synthesis of higher alcohols by ethanol fixed bed

[0073]

[0074]

Claims

1. A pretreatment method for an alumina-supported copper oxide-rare earth metal oxide catalyst for ethanol to higher alcohol reaction, characterized in that The pretreatment method comprises: adding an alumina-supported copper oxide-rare earth metal oxide catalyst used for the reaction of ethanol to prepare higher alcohols to a mixed solution of one or more C1-C8 alcohols, impregnating at 10-90° C. for 1-24 hours, filtering to remove excess alcohol after the impregnation, and then drying in an oven at 40-200° C. for 1-24 hours to complete the pretreatment of the catalyst.

2. The pretreatment method according to claim 1, characterized in that: The impregnation is carried out under shaking conditions.

3. The pretreatment method according to claim 1, characterized in that: The C1-C8 alcohol is selected from at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, n-pentanol, n-hexanol, n-heptanol and n-octanol.

4. The pretreatment method according to claim 1, characterized in that: The alumina-supported copper oxide-rare earth metal oxide catalyst for ethanol to higher alcohol reaction comprises an alumina carrier and copper oxide and rare earth metal oxide supported on the surface thereof. The content of each component in the alumina-supported copper oxide-rare earth metal oxide catalyst is expressed in mass percentage as follows: Alumina carrier 55%~96.5% Copper oxide 2%~25% Rare earth metal oxides 1.5%~20% The rare earth metal element contained in the alumina-supported copper oxide-rare earth metal oxide catalyst is lanthanum, samarium or praseodymium.

5. The pretreatment method according to claim 1, characterized in that: In the alumina-supported copper oxide-rare earth metal oxide catalyst, the molar ratio of copper oxide to rare earth metal oxide is 3:1 to 3:

6.

6. The pretreatment method according to claim 1, characterized in that: The alumina carrier is in granular form with a specific surface area of ​​180 to 450 m 2 / g, average pore diameter 1-15nm, pore volume 0.3-1.5mL / g.

7. The pretreatment method according to claim 1, characterized in that: The specific preparation steps of the alumina-supported copper oxide-rare earth metal oxide catalyst are as follows: (1) immersing a dried alumina support in a mixed solution of copper oxide and a rare earth metal oxide precursor, shaking and mixing, and then standing for 1 to 48 hours; (2) drying the mixture obtained in step (1) so that the precursors of copper oxide and rare earth metal oxide are evenly loaded on the inner and outer surfaces of the alumina support; (3) placing the alumina carrier loaded with copper oxide and rare earth metal oxide precursor obtained by drying in step (2) in a muffle furnace and calcining at 300-800° C. in air or inert gas atmosphere for 0.5-24 h to obtain an alumina-loaded copper oxide-rare earth metal oxide catalyst.

8. The pretreatment method according to claim 7, characterized in that: The copper oxide precursor is a soluble copper salt; the rare earth metal oxide precursor is one or a mixture of rare earth metal nitrates and acetylacetonates; the solvent for preparing a mixed solution of copper oxide and rare earth metal oxide precursors is one or a mixture of any proportion of two or more of deionized water, methanol, ethanol, isopropanol, acetylacetone, chloroform, tetrahydrofuran and N,N-dimethylformamide.

9. Use of the alumina-supported copper oxide-rare earth metal oxide catalyst treated by the pretreatment method according to any one of claims 1 to 8 in the reaction of ethanol to produce higher alcohols.

10. The use according to claim 9, characterized in that: The reaction of preparing higher alcohols from ethanol is continuously carried out in a fixed bed reactor. The alumina-supported copper oxide-rare earth metal oxide catalyst treated by the pretreatment method according to any one of claims 1 to 8 is in-situ reduced with ethanol before use. The reduction conditions are: temperature of 150 to 300° C., pressure of normal pressure to 6.0 MPa, and liquid space velocity of ethanol of 0.5 to 5.0 mL / (h·g cat ), volume ratio of nitrogen / ethanol = 100-800:1; the reaction conditions of the ethanol to higher alcohol reaction are: temperature of 200-300°C, pressure of normal pressure-6.0MPa, liquid space velocity of ethanol of 0.5-5.0mL / (h·g cat ).

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