WO2022247717A1 - Method for synthesizing higher alcohol by means of catalytic conversion of ethanol - Google Patents

Abstract

Disclosed in the present invention is a method for synthesizing a higher alcohol by means of catalytic conversion of ethanol. According to the method, ethanol is used as a raw material and is reacted under the action of a catalyst to generate a higher alcohol. The method is characterized in that the catalyst is a homogeneous mixture of a catalyst I and a catalyst II at a mass ratio of 1:10 to 10:1, the catalyst I is a solid catalyst for the dehydrogenation condensation of ethanol to generate the higher alcohol, and the catalyst II is a solid catalyst having the function of catalyzing an aldol condensation reaction of aldehydes or ketones containing α-H, more aldol condensation active centers are introduced on the basis of catalyst I, and both synergistically catalyze the conversion of ethanol into a higher alcohol. The present invention simultaneously improves the selectivity for a higher alcohol and the conversion rate of ethanol, and ultimately realizes the efficient conversion of ethanol into a higher alcohol under relatively mild reaction conditions without generating small-molecule cracking products. Moreover, the catalyst has excellent stability.

Description

A method for ethanol catalytic conversion to synthesize higher alcohols (1) Technical field

The invention relates to a method for synthesizing higher alcohols (mainly including C4-C8 alcohols) through catalytic conversion of ethanol.

(2) Background technology

Using bioethanol as a gasoline additive can increase gasoline octane while reducing greenhouse gas emissions, so it is generally accepted in the United States, China, Brazil and some European countries. However, ethanol is not an ideal gasoline blending component because of its strong hygroscopicity and low energy density. The bio-butanol prepared by upgrading bio-ethanol has higher calorific value and low corrosion, and can be used directly without modification of the engine, so it becomes a more ideal biofuel than bio-ethanol. In addition, butanol is also an important chemical raw material for the synthesis of dibutyl phthalate, butyl acrylate and other plastic/rubber plasticizers or coating/adhesive monomers. Industrial butanol is mainly synthesized from petroleum-based propylene through homogeneous carbonylation and hydrogenation reactions. The raw material is non-renewable, the process is complicated, the catalyst is expensive, and the production cost is high. On the other hand, the process of producing biomass ethanol by biological fermentation is quite mature and has a large industrial scale, and the global production of bioethanol is increasing year by year. Therefore, the conversion of bioethanol and ethanol from other sources into butanol and higher value-added higher alcohols such as hexanol and octanol by catalytic conversion has become one of the current academic and industrial hotspots.

The dehydrogenation of ethanol to higher alcohols follows the Guerbet mechanism, which mainly consists of three series reactions: dehydrogenation of ethanol to acetaldehyde, aldol condensation of acetaldehyde to crotonaldehyde, and hydrogenation of crotonaldehyde to butanol. Butanol can react with itself or ethanol to produce higher alcohols with higher carbon number such as hexanol and octanol through Guerbet reaction. In the published literature, the complex catalysts of iridium and ruthenium are used in the reaction of ethanol dehydrogenation and condensation to produce n-butanol, and have achieved higher selectivity and yield of butanol, but its preparation is complicated, and the use of hydrogen oxidation Soluble strong bases such as sodium and sodium ethoxide are used as catalysts in the aldol condensation step of acetaldehyde, especially if they use tank reactors, the separation of catalysts is difficult, and the reaction cannot be carried out continuously, which is not conducive to the large-scale production of butanol fuel [Angew. Chem.Int.Ed., 2013, 52, 9005-9008; J.Am.Chem.Soc., 2015, 137, 14264-14267]. Metal-supported multifunctional catalysts are widely used in the dehydrogenation condensation of ethanol to n-butanol, and exhibit superior performance. For example, the Cu/HAS-CeO ₂ catalyst with high specific surface CeO ₂ supports shows 67% ethanol conversion and 30% butanol yield (butanol is the main product) at a reaction temperature of 250°C, but it requires It is carried out in supercritical _CO2 medium, and the reaction pressure higher than 10MPa has high requirements on the material of the reaction equipment, and the production capacity of butanol per unit volume of the reactor is low, and its industrial application is also restricted to a certain extent [Green chemistry, 2015 , 17:3018-3025]. Ni-doped magnesium-aluminum composite oxides exhibited 18.7% conversion of ethanol and 15.9% yield of _C4 - _C6 alcohols under the reaction conditions of 250°C, 3MPa(N2), LHSV=3h ^-1 _[ Journal of Catalysis,2016,344:184-193]; and the use of Ni/Al ₂ O ₃ catalyst can also obtain 25% ethanol conversion and 20% butanol yield under the reaction conditions of 250°C and 7MPa(Ar) (Butanol is the main product) [Catalysts, 2012, 2:68-84]. Although the above-mentioned Ni catalyst can be used to obtain high butanol selectivity, its ethanol conversion activity is relatively low; at the same time, due to the strong CC bond cracking ability of metallic Ni, cracking products such as CH ₄ , CO, and CO ₂ will be produced. Resulting in a decrease in the yield of liquid products. However, the research group of the present invention has developed a copper-cerium oxide catalyst supported by activated carbon, which can be used under relatively mild reaction conditions (250°C, 2MPa, LHSV=2h ^-1 , nitrogen/ethanol=500:1 (volume ratio)) The C4-C8 alcohol selectivity and yield are as high as 61.0% and 28.2%, and there is no generation of cracking products such as CH ₄ , CO, CO ₂ [CN106076344 B; Chem.Commun., 2016,52:13749-13752 ]. Recently, the research group of the present invention also applied metal-organic framework-confined nano-Pd catalyst (Pd@UiO-66) to the reaction of ethanol dehydrogenation and condensation to n-butanol, and achieved up to 38.7% C4 under the conditions of 250°C and 2MPa -C8 alcohol yield, but the preparation of the catalyst is complicated, expensive, and 13.9% cracked products are produced, so it is also unfavorable for its large-scale preparation and application [CN108636453 B; ACS Catal., 2018, 8, 11973-11978 ].

The invention provides a method for synthesizing higher alcohols by catalytic conversion of ethanol, using copper-based multifunctional supported catalyst I and supported catalyst II with acid-base centers to synergistically catalyze the conversion of ethanol to prepare higher alcohols. The reaction is carried out continuously in a fixed-bed reactor, and the catalyst I and catalyst II are uniformly mixed and loaded. By introducing Catalyst II, the number of active centers for aldol condensation of acetaldehyde is greatly increased, which not only significantly improves the selectivity of higher alcohols, but also moves the ethanol dehydrogenation equilibrium to the right, increasing the conversion rate of ethanol, and finally in a relatively mild The reaction conditions obtained were as high as 82.8% and 46.2% higher alcohol selectivity and yield, and no small molecular cracking products were produced. The two catalysts in the invention act synergistically, have high catalytic efficiency, no small molecular cracking products, low catalyst cost, simple process flow and mild reaction conditions, and are suitable for large-scale production of higher alcohols through continuous catalytic conversion of ethanol through a fixed bed.

(3) Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for synthesizing higher alcohols through efficient catalytic conversion of ethanol.

In order to realize the above-mentioned purpose of the invention, the present invention adopts following technical scheme:

A method for synthesizing higher alcohols by catalytic conversion of ethanol. The method uses ethanol as a raw material to react to generate higher alcohols under the action of a catalyst. The catalyst is Catalyst I and Catalyst I with a mass ratio of 1:10 to 10:1. A homogeneous mixture of II, the catalyst I is a solid catalyst for ethanol dehydrogenation condensation to generate higher alcohols, and the catalyst II is a solid catalyst with the function of catalyzing the aldol condensation reaction of aldehydes or ketones containing α-H, On the basis of catalyst I, more aldol condensation active centers are introduced, and the two synergistically catalyze the conversion of ethanol to higher alcohols.

In the present invention, the catalyst I is a solid catalyst for synthesizing higher alcohols through dehydrogenation and condensation of ethanol, which has the functions of catalyzing ethanol dehydrogenation, aldol condensation of acetaldehyde, and hydrogenation of crotonaldehyde.

Preferably, the catalyst I is an alumina-supported copper-rare earth metal oxide catalyst (Cu-MO _x /Al ₂ O ₃ ), which includes a carrier alumina and a copper active component supported on the surface of the carrier alumina and Rare earth metal oxide active component MO _x , the content of each component in the catalyst is expressed as follows in mass percent:

Carrier alumina 65%～98.9%

Copper active component 0.1%～15%

Rare earth metal oxide active component MO _x 1% to 20%;

Where M represents a rare earth metal, x=1, 1.5 or 2, and the copper active component exists in two forms of +1-valent Cu and zero-valent Cu, and the molar ratio of the two satisfies the following conditions: Cu ⁰ /Cu ⁺ =1: 13.1～1:4.

As a further preference, the content of each component in the alumina-supported copper-rare earth metal oxide catalyst is expressed in mass percent as follows:

Carrier alumina active component 73%～97.5%

Copper active component 0.5%～12%

Rare earth metal oxide active component MO _x 2% to 15%.

Preferably, the molar ratio of +1-valent Cu to zero-valent Cu in the alumina-supported copper-rare earth metal oxide catalyst satisfies the following condition: Cu ⁰ /Cu ⁺ =1:10˜1:6.

The alumina-supported copper-rare earth metal oxide catalyst of the present invention may contain other components that do not have a substantial impact on its catalytic performance, such as those introduced due to the use of commercial alumina carriers, soluble copper salts and rare earth metal salts, etc. small amount of impurities. Preferably, the alumina-supported copper-rare earth metal oxide catalyst (Cu-MO _x /Al ₂ O ₃ ) consists of carrier alumina and copper active components and rare earth metal oxide active components supported on the surface of carrier alumina Component MO _x composition.

In the alumina-supported copper-rare earth metal oxide catalyst of the present invention, the carrier alumina is granular, and there is no special requirement on its particle size. The particle diameter of the generally used alumina carrier is 0.2-5 mm. Preferably, the alumina support is granular, with a specific surface of 180-450 m ² /g, an average pore diameter of 1-12 nm, and a pore volume of 0.3-1.5 mL/g. .

In the alumina-supported copper-rare earth metal oxide catalyst of the present invention, in the rare earth metal oxide _MOx , M represents a rare earth metal, which can be Ce, La, Pr, Nd, Sm, Eu, Ho , Er, Sc, Y, etc. The rare earth metal oxide MO _x in the catalyst of the present invention may be one of CeO ₂ , La ₂ O ₃ , Sm ₂ O ₃ , Sc ₂ O ₃ , Y ₂ O _{3 ,} etc., or a mixture of two or more in any proportion.

In the alumina-supported copper-rare earth metal oxide catalyst of the present invention, the Cu ^O is supported on the surface of the carrier in the form of nanoparticles, and the Cu ⁺ is mainly highly dispersed on the surface of the alumina carrier in the form of single atoms, so The above-mentioned rare earth metal oxide active component MO _x is also in a highly dispersed state on the surface of the alumina carrier. This is because, there are strong interactions among the copper active components, _MOx , and alumina support, and these strong interactions inhibit the reduction of surface CuO species and stabilize Cu nanoparticles as well as Cu ⁺ and _MOx by forming chemical bonds. , thus not only greatly improving the dispersibility, but also enhancing the stability of Cu and La species. The structural characteristics of the alumina-supported copper-rare earth metal oxide catalyst of the present invention make it particularly suitable for the reaction of ethanol dehydrogenation and condensation to prepare higher alcohols (C4-C8 alcohols), and atomically dispersed Cu ⁺ and Cu nanoparticles are beneficial Dehydrogenation of ethanol and subsequent hydrogenation of crotonaldehyde, while the highly dispersed _MOx and the alumina support itself provides sufficient active sites for the aldol condensation of aldehydes, thereby driving the reaction equilibrium towards the production of higher alcohols .

Preferably, the alumina-supported copper-rare earth metal oxide catalyst is prepared by a preparation method comprising the following steps: loading the precursor of copper precursor and rare earth metal oxide MO _x on the surface of alumina support by wet impregnation , and then the alumina carrier loaded with the precursor is calcined in air or an inert gas atmosphere (the calcining temperature is preferably 400-800°C), and then the calcined product is subjected to high-temperature reduction treatment at 350-500°C in a reducing gas, and finally An aluminum oxide supported copper-rare earth metal oxide catalyst is obtained. By controlling the reduction temperature, this method can not only effectively control the molar ratio of Cu ⁰ and Cu ⁺ in the catalyst, but also adjust the acid-base properties of the catalyst surface to achieve the balance of acid-base sites, which can more effectively promote the Aldol condensation reaction, which further drives the reaction equilibrium to promote the production of higher alcohols.

In a second aspect, the present invention provides a method for preparing the alumina-supported copper-rare earth metal oxide catalyst (Cu-MO _x /Al ₂ O ₃ ), comprising the following steps:

(1) Immerse the dry alumina carrier in the mixed solution of the copper precursor and the precursor of the rare earth metal oxide _MOx , stir and mix and let stand for 1-48h;

(2) Drying the mixture obtained in step (1), so that the copper precursor and the precursor of the rare earth metal oxide MO _x are evenly loaded on the inner and outer surfaces of the alumina carrier;

(3) putting the precursor-loaded alumina carrier obtained by drying in step (2) into a muffle furnace and roasting for 0.5-48 hours at 400-800° C. in an air or inert gas atmosphere;

(4) The calcined product of step (3) is subjected to high-temperature reduction treatment at 350-500° C. in a reducing gas to finally obtain an alumina-supported copper-rare earth metal oxide catalyst.

In the above preparation method, the copper precursor may be copper nitrate, copper chloride, copper acetate, copper acetylacetonate and other soluble copper salts. The precursor of the rare earth metal oxide MO _x can be soluble salts such as nitrates and acetylacetonate salts of rare earth metals. The solvent for preparing the mixed solution of the copper precursor and the MO _x precursor can be one of deionized water, methanol, ethanol, isopropanol, acetylacetone, chloroform, tetrahydrofuran and N,N-dimethylformamide, etc. A mixture of two or more in any proportion. The concentration and ratio of the two precursors in the mixed solution of the precursor of the copper precursor and the rare earth metal oxide MO _x can be determined according to the loading of the copper active component and the rare earth metal oxide MO _x in the desired catalyst, Generally speaking, the concentration of the copper precursor in the solution is between 0.05-1.0 mol/L, and the concentration of the precursor of the rare earth metal oxide MO _x is between 0.05-1.0 mol/L.

As a preference, the drying treatment described in step (2) is carried out in a rotary evaporator, first dried at 10-60°C and 0.005-0.1MPa for 0.5-24h, and then dried at 65-95°C and 0.005-0.1MPa 0.5～10h.

Preferably, in step (4), the reducing gas is hydrogen or a mixture of hydrogen/gas A, the gas A is an inert gas or nitrogen, and the volume percentage of hydrogen in the reducing gas is 0.5% to 100%.

Preferably, the high-temperature reduction treatment is carried out in a flowing reducing gas, the space velocity of the reducing gas is 50-5000h ^-1 , the reduction temperature is 350-500°C, and the reduction time is 0.5-48h. More preferably, the reduction temperature is 450-500° C., and the reduction time is 5-10 hours.

The catalyst II in the present invention is a solid catalyst with the function of catalyzing the aldol condensation reaction of aldehydes or ketones containing α-H, preferably a solid catalyst with the function of catalyzing the aldol condensation reaction of acetaldehyde.

Preferably, the catalyst II is an alumina-supported metal oxide catalyst, which includes an alumina carrier and a metal oxide active component loaded on the alumina carrier, and the metal oxide active component is a rare earth metal At least one of the oxides; in the catalyst, the content of each component is expressed as follows in mass percent:

Alumina carrier 80%～99.9%

Metal oxide active components 0.1% to 20%.

The alumina-supported 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 by using commercial alumina supports, soluble metal salt chemical reagents, and the like. Preferably, the alumina-supported metal oxide catalyst consists of carrier alumina and metal oxide active components supported on the surface of the carrier alumina.

In the present invention, the carrier alumina is granular, and there is no special requirement on its particle size. The particle diameter of the generally used alumina carrier is 0.2-5mm. Preferably, the alumina support is granular, with a specific surface of 180-450 m ² /g, an average pore diameter of 1-12 nm, and a pore volume of 0.3-1.5 mL/g.

In the alumina-supported metal oxide catalyst of the present invention, the metal oxide is at least one selected from rare earth metal oxides. In the rare earth metal oxide MO _x , M represents a rare earth metal, such as Ce, La, Pr, Nd, Sm, Eu, Ho, Er, Sc, Y, etc., x=1, 1.5 or 2. The rare earth metal oxide MO _x in the catalyst of the present invention may be one of CeO ₂ , La ₂ O ₃ , Sm ₂ O ₃ , Sc ₂ O ₃ , Y ₂ O _{3 ,} etc., or a mixture of two or more in any proportion.

Preferably, the alumina-supported metal oxide catalyst is prepared by a preparation method comprising the following steps: loading the precursor of the rare earth metal oxide on the surface of the alumina support by wet impregnation, and then oxidizing the precursor loaded with The aluminum carrier is calcined in air or an inert gas atmosphere (the calcining temperature is preferably 400-800° C.), and an alumina-supported metal oxide catalyst is finally obtained.

The present invention also provides a method for preparing the alumina-supported metal oxide catalyst, comprising the following steps:

(a) immersing the dry alumina carrier in the solution of the precursor of the metal oxide, stirring and mixing and then standing still for 1-48h;

(b) drying the mixture obtained in step (a), so that the precursor of the metal oxide is evenly loaded on the inner and outer surfaces of the alumina carrier, and the alumina carrier supporting the precursor is obtained;

(c) Put the precursor-loaded alumina carrier obtained by drying in step (b) into a muffle furnace and bake at 400-800°C for 0.5-48 hours in an air or inert gas atmosphere to finally obtain an alumina-supported metal oxide catalyst.

In the above preparation method, the precursor of the metal oxide may be a soluble salt such as metal nitrate or acetylacetonate. The solvent for preparing the precursor solution of the metal oxide can be one or both of deionized water, methanol, ethanol, isopropanol, acetylacetone, chloroform, tetrahydrofuran and N,N-dimethylformamide, etc. A mixture of the above in any proportion. The concentration of the precursor in the solution of the metal oxide precursor is determined according to the loading capacity of the metal oxide MO _x in the catalyst. Generally speaking, the concentration of the metal oxide precursor in the solution is between 0.05 and 1.0 between mol/L.

As a preference, the drying treatment described in step (b) is carried out in a rotary evaporator, first dried at 10-60°C and 0.0005-0.1MPa for 0.5-24h, and then dried at 65-95°C and 0.0005-0.1MPa 0.5～10h.

The reaction of catalytic conversion of ethanol to synthesize higher alcohols described in the present invention can be carried out in reactors such as fixed bed, ebullating bed, tank reactor, etc. When loading the catalyst, the catalysts I and II can be mixed uniformly in advance, and then Packed into the catalyst zone of the reactor.

The method for synthesizing higher alcohols through catalytic conversion of ethanol in the present invention is suitable for continuous reaction process and also suitable for batch reaction process.

As a preference, the reaction described in the present invention is carried out continuously in a fixed-bed reactor, and the catalyst I and catalyst II are uniformly mixed and then filled in the isothermal zone of the reaction tube.

As a further preference, the reaction is carried out continuously in a fixed-bed reactor, and the catalyst I and catalyst II are uniformly mixed and then filled in the isothermal zone of the reaction tube. The reaction conditions for the continuous catalytic synthesis of higher alcohols by ethanol are: The temperature is 150-300°C, the reaction pressure is 0.1-5.0MPa, the liquid space velocity is 0.2-6.0mL/(h·g·cat), nitrogen/ethanol=100-1000:1 (volume ratio). Under this condition, the combined catalyst of the present invention is applied to the continuous catalytic synthesis of higher alcohols by fixed-bed ethanol, and its higher alcohol selectivity and yield are high. Ethanol can be recycled.

The higher alcohols in the present invention refer to C4-C8 alcohols, including n-butanol, n-hexanol, 2-ethylbutanol, n-octanol, 2-ethylhexanol and the like.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

(1) The present invention introduces a solid catalyst that catalyzes the aldol condensation reaction of aldehydes or ketones containing α-H on the basis of a single solid catalyst used for ethanol dehydrogenation condensation to generate higher alcohols by means of uniform mixing, As a result, more aldol condensation active centers are introduced, which greatly promotes the aldol condensation of acetaldehyde, and at the same time pulls the ethanol dehydrogenation equilibrium to move to the right, thereby simultaneously improving the higher alcohol selectivity and ethanol conversion rate, and finally in a relatively mild reaction Under the conditions, the high-efficiency conversion of ethanol to higher alcohols is realized, and no small molecular cracking products are produced; and the catalyst has excellent stability.

(2) In the catalyst I used in the present invention——Cu-MO _x /Al ₂ O ₃ catalysts, due to the strong interaction between copper, rare earth metal oxides and alumina supports, the copper active components, Rare earth metal oxides are highly dispersed and stable on the alumina support, and the Cu active component is +1-valent Cu (dispersed at the atomic level or present at the interface between Cu nanoparticles and the oxide support) and zero-valent Cu ( Existing in the form of Cu nanoparticles) in a certain proportion, this structural feature makes the catalyst have a large number of efficient and stable ethanol dehydrogenation, crotonaldehyde hydrogenation and acetaldehyde aldol condensation active centers, and finally makes the catalyst can be used as A high-efficiency and high-stability catalyst for producing higher alcohols from ethanol.

(3) The preparation method of the catalyst of the present invention is simple and convenient, and the cost is low. By controlling the reduction temperature, not only the molar ratio of Cu ⁰ and Cu ⁺ in the catalyst is effectively controlled, but also the balance of the acid-base sites on the catalyst is realized, and the balanced Cu ⁺ -Cu The synergistic effect of ⁰ site and balanced acid-base site makes the catalyst have higher ethanol dehydrogenation activity and higher alcohol selectivity.

(4) In the catalyst II used in the present invention——alumina-supported metal oxide catalyst, the alumina carrier and the rare earth metal oxides supported by it provide a large number of moderate-strength Lewis acid and Lewis base catalytic active sites respectively, and these acids Alkaline active centers act synergistically, so that the catalyst has high aldol condensation activity; and the catalyst also has good stability.

(5) The combined catalyst of the present invention is suitable for the industrialized production of ethanol fixed-bed continuous catalytic conversion to synthesize higher alcohols, and overcomes the complexity of catalyst preparation and separation difficulties in the batch reaction process using homogeneous catalysts or powdery catalysts, labor intensity is large, A series of problems such as unsafe production operations.

(6) The present invention creatively supports the Cu-MO _x /Al ₂ O ₃ catalyst with the function of catalyzing the dehydrogenation condensation of ethanol to generate higher alcohols and the alumina with the function of catalyzing the aldol condensation reaction of aldehydes or ketones containing α-H Type metal oxide catalysts are uniformly mixed and loaded in a fixed-bed reactor, and through the synergistic effect between the two, the efficient conversion of ethanol to higher alcohols is realized. The two catalysts in the present invention act synergistically, have high catalytic efficiency, no small molecular cracking products, excellent stability, low catalyst cost, simple process flow, mild reaction conditions, and are suitable for large-scale production of ethanol through fixed-bed continuous catalytic conversion. alcohol.

(4) Description of drawings

Fig. 1 is the HRTEM image (A), the HAADF-STEM image and the corresponding element distribution images (B and C) of the Cu-La ₂ O ₃ /Al ₂ O ₃ catalyst prepared in Example 5.

Fig. 2 is another HAADF-STEM image and corresponding element distribution image (A), HRTEM image and corresponding crystal diffraction image (B) of the Cu-La ₂ O ₃ /Al ₂ O ₃ catalyst prepared in Example 5.

Figure 3 is the XRD patterns of Cu-La ₂ O ₃ /Al ₂ O ₃ catalysts obtained by reduction at different temperatures: (a) Comparative Example 3, 250°C; (b) Comparative Example 4, 350°C; (c) implementation Example 5, 500°C; (d) Comparative Example 5, 550°C.

Figure 4 shows the Cu 2p XPS (A) and Cu LMM spectra (B) of Cu-La ₂ O ₃ /Al ₂ O ₃ catalysts reduced at different temperatures: (a) Comparative Example 3, 250°C; (b) Comparative Example 4, 350°C; (c) Example 5, 500°C; (d) Comparative Example 5, 550°C.

Fig. 5 is the schematic diagram of ethanol continuous catalytic conversion synthesis higher alcohol fixed-bed reaction device; Among Fig. 1, 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-one-way valve, 10-reaction tube, 11-reaction furnace, 12-condenser, 13-condensed water outlet, 14-condensed water inlet, 15- Filter, 16-back pressure valve, 17-product collection tank.

Fig. 6 is the result of the stability test of the catalyst Ie prepared according to Example 5 in the reaction of the continuous catalytic conversion of ethanol to higher alcohols in a fixed bed; the reaction conditions are: temperature 260°C, pressure 3.0MPa, liquid space velocity is 2mL/(h ·g·cat), nitrogen/ethanol=250:1 (volume ratio). Due to the strong interaction between copper, rare earth metal oxides and alumina support, the sintering of copper and rare earth metal oxides is limited, so that the Cu-MO _x /Al ₂ O ₃ catalyst can be used in the reaction of ethanol to higher alcohols It shows excellent stability and shows good prospects for industrial application.

Fig. 7 is the X-ray diffraction (XRD) spectrogram of catalyst Ie prepared according to embodiment 5 in described fixed-bed ethanol continuous catalytic conversion synthetic higher alcohol reaction 200h before and after catalyst, reaction condition is: temperature 260 ℃, pressure 3.0 MPa, the liquid space velocity is 2mL/(h·g·cat), nitrogen/ethanol=250:1 (volume ratio). It can be seen that the active components of copper and La ₂ O ₃ are highly dispersed on the surface of alumina support, and after 200 hours of reaction, only a small number of Cu nanoparticles grow slightly, and most of Cu and La ₂ O ₃ still maintain a high degree of scattered state.

(5) Specific implementation methods

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

The alumina carrier used in the examples is granular, with a particle diameter of 0.2-5 mm, a specific surface of 291 m ² /g, an average pore diameter of 10.1 nm, and a pore volume of 0.74 mL/g.

Example 1

Add 0.7603g of copper nitrate (Cu(NO ₃ ) ₂ 3H ₂ O) and 0.4555g of cerium nitrate (Ce(NO ₃ ) ₃ 6H ₂ O) into 10ml of absolute ethanol, and after they are dissolved and mixed evenly, Add 2g of alumina carrier (specific surface: 291m ² /g, average pore diameter: 10.1nm, pore volume: 0.74mL/g) into it and impregnate for 4h. The above mixture was first dried on a rotary evaporator at 50° C. and 0.09 MPa for 3 hours, and then dried at 80° C. and 0.09 MPa for 2 hours. The dried solid matter is calcined in a muffle furnace at 450°C in an air atmosphere for 3 hours, and then in a tube furnace or a fixed bed reactor with 10% H ₂ /N ₂ mixed gas at 500°C and a gas space velocity Catalyst Ia was obtained by reducing for 6h under the condition of 1800h ^-1 . Its weight content of metal Cu is 8.4wt%, the loading amount of _CeO2 is 7.6wt%, and the rest is alumina support. Using X-ray fluorescence spectroscopy (XPS) to analyze the surface element composition and valence state of the catalyst, it is proved that in the reduced catalyst, cerium exists in the form of CeO ₂ , while the copper active components are in the form of +1-valent Cu and zero-valent Cu Both forms exist and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:6.4.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Ia, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 2

The preparation method of catalyst Ib was the same as that in Example 1, but the masses of copper nitrate (Cu(NO ₃ ) ₂ ·3H ₂ O) and cerium nitrate (Ce(NO ₃ ) ₃ ·6H ₂ O) were 0.6083g and 0.4555g, respectively. The weight content of its metal Cu is 6.8wt%, the weight content of _CeO2 is 7.7wt%, and the rest is alumina carrier. Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that in the reduced catalyst, cerium exists in the form of CeO ₂ , while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu, and The Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:6.9.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Ib, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 3

Add 0.7603g of copper nitrate (Cu(NO ₃ ) ₂ 3H ₂ O) and 0.4542g of lanthanum nitrate (La(NO ₃ ) ₃ 6H ₂ O) into 10ml of absolute ethanol, and after they are dissolved and mixed evenly, Add 2g of alumina carrier into it and impregnate for 4h. The above mixture was first dried on a rotary evaporator at 50° C. and 0.09 MPa for 3 hours, and then dried at 80° C. and 0.09 MPa for 2 hours. The dried solid matter is calcined in a muffle furnace at 450°C in an air atmosphere for 3 hours, and then in a tube furnace or a fixed bed reactor with 10% H ₂ /N ₂ mixed gas at 500°C and a gas space velocity Catalyst Ic was obtained by reduction under the condition of 1800h ^-1 for 6h. The weight content of metal Cu is 8.4wt%, the weight content of _La2O3 is 7.7wt%, and the rest is alumina _carrier . Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:6.0.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Ic, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 4

The preparation method of the catalyst Id is the same as in Example 3, but the mass of lanthanum nitrate (La(NO ₃ ) ₃ ·6H ₂ O) is 0.3407g. The weight content of metal Cu is 8.6wt%, the weight content of _La2O3 is 5.9wt%, and the rest is alumina _carrier . Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:6.2.

The continuous catalytic conversion of ethanol to synthesize higher alcohols fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Id, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 5

The preparation method of catalyst Ie is the same as in Example 3, but the quality of copper nitrate (Cu(NO ₃ ) ₂ 3H ₂ O) is 0.4562g, and the quality of lanthanum nitrate (La(NO ₃ ) ₃ .6H ₂ O) is 0.2725g . The weight content of metal Cu is 5.4wt%, the weight content of _La2O3 is 4.8wt%, and the rest is alumina _carrier . Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:8.3.

Fig. 1 is the HRTEM image (A), HAADF-STEM image and corresponding EDX mapping image (B and C) of the catalyst I-e prepared in Example 5.

Fig. 2 is another HAADF-STEM image and corresponding EDX mapping image (A), HRTEM image and corresponding crystal diffraction image (B) of catalyst I-e prepared in Example 5.

As can be seen from (A) of Fig. 1, apart from the lattice fringes _of the alumina grains and their various crystal planes, no distinguishable Cu or _La2O3 nanoparticles were found in the typical HRTEM photograph of catalyst Ie, This indicates that metallic Cu and La ₂ O ₃ should be highly dispersed on the Cu-La ₂ O ₃ /Al ₂ O ₃ catalyst, while Fig. 1(B) shows that there are a large number of single atoms in typical HAADF-STEM pictures Cu. HAADF-STEM and corresponding EDX mapping analysis (Fig. 1(C)) further confirmed the highly dispersed nature of copper and lanthanum species on the alumina support.

The HAADF-STEM and corresponding EDX mapping analysis of Fig. 2 confirmed that a small amount of copper exists in the form of nano-copper; the HRTEM image and corresponding crystal diffraction pattern in Fig. 2 further confirmed the above results.

(c) of FIG. 3 shows the XRD pattern of catalyst Ie. It can be seen from the figure that the Cu-La ₂ O ₃ /Al ₂ O ₃ catalyst exhibits extremely weak Cu diffraction peaks, indicating that metal Cu is highly dispersed on these catalysts; and no La ₂ O ₃ is found in the XRD patterns of the catalysts. Characteristic diffraction peaks, which indicate that La ₂ O ₃ is also highly dispersed on these catalysts.

Figure 4(c) shows the Cu 2p XPS (A) and Cu LMM spectra (B) of catalyst Ie. It can be seen from Figure 4 that the Cu ²⁺ in the copper precursor has been reduced to Cu ⁺ and Cu ⁰ , the former is the main form, and the Cu ⁰ /Cu ⁺ ratio is calculated from the relative peak areas of the Cu ⁺ and Cu ⁰ peaks (Molar ratio) is 1:8.3.

From Figures 1 to 4, it can be concluded that there are two types of Cu components on the surface of the catalyst Ie, that is, Cu ⁺ that is atomically dispersed on the surface of the alumina support or exists at the interface between the Cu nanoparticles and the alumina support and A small amount of Cu ⁰ in the form of nanoparticles and La ₂ O ₃ are also highly dispersed on the surface of catalyst Ie.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Ie, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 6

The preparation method of catalyst If is the same as in Example 3, but the quality of copper nitrate (Cu(NO ₃ ) ₂ 3H ₂ O) is 0.2281g, and the quality of lanthanum nitrate (La(NO ₃ ) ₃ .6H ₂ O) is 0.1362g . The weight content of metal Cu is 2.8wt%, the weight content of _La2O3 is 2.4wt% _, and the rest is alumina carrier. Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:9.1.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst If, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 7

The preparation method of catalyst Ig is the same as in Example 5, but 0.2725 g of lanthanum nitrate (La(NO ₃ ) ₃ ·6H ₂ O) is replaced by 0.2798 g of samarium nitrate (Sm(NO ₃ ) ₃ ·6H ₂ O). The weight content of metal Cu is 5.5wt%, the weight content of _Sm2O3 is 4.9wt%, and the rest is alumina _carrier . Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that samarium exists in the form of Sm ₂ O ₃ in the reduced catalyst, while copper active components exist in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:8.2.

Continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reactor as shown in Figure 5, take 1g of catalyst Ig, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 8

The preparation method of catalyst Ih is the same as in Example 5, but 0.2725 g of lanthanum nitrate (La(NO ₃ ) ₃ ·6H ₂ O) is replaced by 0.2738 g of praseodymium nitrate (Pr(NO ₃ ) ₃ ·6H ₂ O). The weight content of metal Cu is 5.5wt%, the weight content of _Pr2O3 is 4.7wt% _, and the rest is alumina carrier. Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that praseodymium exists in the form of Pr ₂ O ₃ in the reduced catalyst, and the copper active component exists in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:8.2.

Continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reactor as shown in Figure 5, take 1g of catalyst 1h, then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Comparative example 1

The preparation and reduction methods of catalyst Ii are the same as in Example 5, but lanthanum nitrate (La(NO ₃ ) ₃ ·6H ₂ O) is not added. The weight content of metal Cu is 5.7wt%, and the rest is alumina carrier. Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that the copper active component exists in two forms of +1-valent Cu and zero-valent Cu in the reduced catalyst, and the Cu ⁰ /Cu ⁺ ratio (mole Ratio) is 1:4.3.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Ii, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Comparative example 2

The preparation and reduction methods of catalyst Ij are the same as in Comparative Example 1, but the original 2 g of alumina carrier is replaced with 2 g of cerium oxide carrier. The weight content of metal Cu is 5.7wt%, and the rest is cerium oxide carrier (specific surface area 82m ^{2 /} g, average pore diameter 4.2nm, pore volume 0.26mL/g). Using XPS and high-resolution transmission electron microscopy (HRTEM) characterization techniques to observe and analyze the surface element composition and valence state of the catalyst, the microscopic morphology and crystal structure of the catalyst, it is proved that cerium exists in the form of _CeO2 in the reduced catalyst , while the copper active component exists in the form of Cu nanoparticles mainly composed of zero-valent copper.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Ij, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Comparative example 3

The preparation and reduction method of catalyst Ik are the same as in Example 5, but the catalyst reduction temperature is 250°C. The weight content of metal Cu is 5.4wt%, the weight content of _La2O3 is 4.8wt%, and the rest is alumina _carrier . Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:17.0.

The continuous catalytic conversion of ethanol to synthesize higher alcohols fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Ik, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Comparative example 4

The preparation and reduction method of catalyst I1 are the same as in Example 5, but the catalyst reduction temperature is 350°C. The weight content of metal Cu is 5.4wt%, the weight content of _La2O3 is 4.8wt%, and the rest is alumina _carrier . Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:13.1.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst I1, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Comparative example 5

The preparation method of catalyst Im is the same as in Example 5, but the catalyst reduction temperature is 550°C. The weight content of metal Cu is 5.4wt%, the weight content of _La2O3 is 4.8wt%, and the rest is alumina _carrier . The surface element composition and valence state of the catalyst were analyzed by XPS characterization technology, and it was proved that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while copper active components exist in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:3.4.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Im, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Comparative example 6

The preparation and reduction method of the catalyst In are the same as in Example 5. The weight content of metal Cu is 5.4wt%, the weight content of _La2O3 is 4.8wt%, and the rest is silica gel carrier (specific surface area ^398m2 /g, average _pore diameter 10.1nm, pore volume 0.96mL/g). Using XPS and HRTEM characterization techniques to observe and analyze the surface element composition and valence state of the catalyst, the microscopic morphology and crystal structure of the catalyst, it proves that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while copper is active The component is in the form of Cu nanoparticles mainly composed of zero-valent copper.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst In and put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Comparative example 7

The preparation and reduction method of catalyst Io are the same as in Example 5. The weight content of metal Cu is 5.4wt%, the weight content of _La2O3 is 4.8wt%, and the rest is activated carbon carrier (specific surface area ^1209.2m2 /g, average _pore diameter 2.6nm, pore volume 0.53mL/g). Using XPS and HRTEM characterization techniques to observe and analyze the surface element composition and valence state of the catalyst, the microscopic morphology and crystal structure of the catalyst, it proves that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while copper is active The component is in the form of Cu nanoparticles mainly composed of zero-valent copper.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Io, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Comparative example 8: Comparative example 2 of CN 106076344 B

Add 0.7603g of copper nitrate (Cu(NO ₃ ) ₂ 3H ₂ O) and 0.4555g of cerium nitrate (Ce(NO ₃ ) ₃ 6H ₂ O) into 10ml of deionized water, and after they are dissolved and mixed evenly, put 2g of alumina carrier was added and impregnated for 4h. The above mixture was first dried on a rotary evaporator at 50° C. and 0.09 MPa for 3 hours, and then dried at 80° C. and 0.09 MPa for 2 hours. The dried solid material was calcined in a tube furnace at 450°C in a nitrogen atmosphere for 3h, and then reduced for 1h with 10% H ₂ /N ₂ mixed gas at 250°C and a gas space velocity of 1800h ^-1 to obtain the catalyst Ip . Its weight content of metal Cu is 8.4wt%, the loading amount of _CeO2 is 7.6wt%, and the rest is alumina support. Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that in the reduced catalyst, cerium exists in the form of CeO ₂ , while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu, and The Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:16.1.

The continuous catalytic conversion of ethanol to synthesize higher alcohol fixed-bed reaction device is shown in Figure 5. Weigh 1g of catalyst Ip, and then put it into the isothermal zone of the reaction tube of the fixed-bed reactor shown in Figure 5. Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 9

Add 0.4562g of copper nitrate (Cu(NO ₃ ) ₂ 3H ₂ O) and 0.3407g of lanthanum nitrate (La(NO ₃ ) ₃ 6H ₂ O) into 10ml of absolute ethanol, and after they are dissolved and mixed evenly, Add 2g of alumina carrier into it and impregnate for 4h. The above mixture was first dried on a rotary evaporator at 50° C. and 0.09 MPa for 3 hours, and then dried at 80° C. and 0.09 MPa for 2 hours. Put the dried solid material in a muffle furnace and roast at 450°C for 4h, and then reduce it in a tube furnace or a fixed bed reactor with 10% H ₂ /N ₂ mixed gas at 500°C and 1800h ^-1 Catalyst Iq was obtained after 6 h. Using XPS characterization technology to analyze the surface element composition and valence state of the catalyst, it is proved that lanthanum exists in the form of La ₂ O ₃ in the reduced catalyst, while the copper active component exists in two forms of +1-valent Cu and zero-valent Cu , and the Cu ⁰ /Cu ⁺ ratio (molar ratio) is 1:8.0.

Add 0.2725g of lanthanum nitrate (La(NO ₃ ) ₃ ·6H ₂ O) into 10ml of absolute ethanol, and after it is dissolved and mixed evenly, add 2g of alumina carrier into it and soak for 4h. Dry the above mixture on a rotary evaporator under the conditions of 50°C and 0.09MPa for 3h, then dry at 80°C and 0.09MPa for 2h, and then place the dried solid in a muffle furnace at 450°C for 4h to obtain Catalyst II-a.

The continuous catalytic conversion of ethanol to synthesize higher alcohols fixed-bed reaction device is shown in Figure 5. Weigh 1.2g of catalyst Iq and 0.8g of catalyst II-a and mix them uniformly to obtain combined catalyst I-q1.2II-a0.8. It is loaded into the isothermal zone of the reaction tube of the fixed bed reactor shown in Fig. 5 . Under the set reaction conditions, _N2 was used as the carrier gas to carry the ethanol raw material into the reactor to start the reaction, and the product was collected and analyzed after condensation.

Example 10

The catalyst preparation, reduction treatment and reaction method of Example 10 are the same as those of Example 9, but the catalyst I-q1II-a1 is obtained by mixing 1.0 g of catalyst I-q and 1.0 g of catalyst II-a uniformly.

Example 11

The catalyst preparation, reduction treatment and reaction method of embodiment 11 are the same as embodiment 9, but what is filled in the reaction tube is to obtain combined catalyst I-q0.8II-a1. 2.

Example 12

The catalyst preparation, reduction treatment and reaction method of embodiment 12 are the same as embodiment 9, but what is filled in the reaction tube is to obtain combined catalyst I-q0.67II-a1. 33.

Example 13

The catalyst preparation, reduction treatment and reaction method of _embodiment 13 are the _same as embodiment 9, but in _the preparation process of catalyst II, replace 0.2725g lanthanum nitrate (La( NO ₃ ) ₃ 6H ₂ O), the prepared catalyst is denoted as catalyst II-b, and what is loaded in the reaction tube is to obtain the combined catalyst I-q1II after mixing uniformly with 1.0g catalyst Iq and 1.0g catalyst II-b -b1.

Comparative example 9

The catalyst preparation, reduction treatment and reaction method of Comparative Example 9 were the same as in Example 9, but 1.0 g of catalyst I-q was filled in the reaction tube.

Comparative example 10

The catalyst preparation, reduction treatment and reaction method of Comparative Example 10 are the same as in Example 9, but 1.0 g of catalyst II-a is filled in the reaction tube.

Comparative example 11

The catalyst preparation, reduction treatment and reaction method of Comparative Example 11 are the same as in Example 9, but the catalyst packed in the reaction tube isothermal zone is divided into two layers, the upper layer is 1.0g catalyst I-q, and the lower floor is 1.0g catalyst II-a. It is I-q1+II-a1.

Comparative example 12

The catalyst preparation of comparative example 12, reduction treatment and reaction method are the same as embodiment 9, but in the preparation process of catalyst II, replace 2.0g alumina carrier with 2.0g gac carrier, the prepared catalyst is denoted as catalyst II-c, and What is filled in the reaction tube is the combined catalyst I-q1II-c1 obtained after mixing uniformly 1.0 g of catalyst I-q and 1.0 g of catalyst II-c.

Table 1 shows the reaction conditions and results of the single catalyst prepared in Examples and Comparative Examples in the continuous dehydrogenation condensation of ethanol to higher alcohols in a fixed bed.

Table 1 Reaction conditions and results of different catalysts in the fixed-bed ethanol continuous dehydrogenation condensation to higher alcohols

The mixed catalysts with different loading methods were used in the continuous catalytic synthesis of higher alcohols in a fixed bed of ethanol, and the results are shown in Table 2.

Table 2 The results of continuous catalytic synthesis of higher alcohols by ethanol fixed bed catalysts with different loading methods

Claims (10)

1. A method for synthesizing higher alcohols by catalytic conversion of ethanol, the method uses ethanol as a raw material, reacts to generate higher alcohols under the action of a catalyst, and is characterized in that the catalyst is a catalyst with a mass ratio of 1:10 to 10:1 A homogeneous mixture of Catalyst I and Catalyst II, the Catalyst I is a solid catalyst for the dehydrogenation and condensation of ethanol to generate higher alcohols, and the Catalyst II has the function of catalyzing the aldol condensation reaction of aldehydes or ketones containing α-H On the basis of catalyst I, more aldol condensation active centers are introduced, and the two synergistically catalyze the conversion of ethanol to higher alcohols.
2. The method according to claim 1, characterized in that: the catalyst I is an alumina-supported copper-rare earth metal oxide catalyst, which includes carrier alumina and copper active components and rare earths loaded on the surface of carrier alumina The metal oxide active component MO _x , the content of each component in the catalyst is expressed as follows in mass percent:

   Carrier alumina 65%～98.9%

   Copper active component 0.1%～15%

   Rare earth metal oxide active component MO _x 1% to 20%;

   Where M represents a rare earth metal, x=1, 1.5 or 2, and the copper active component exists in two forms of +1-valent Cu and zero-valent Cu, and the molar ratio of the two satisfies the following conditions: Cu ⁰ /Cu ⁺ =1: 13.1～1:4.
3. The method according to claim 2, characterized in that: the content of each component in the alumina-supported copper-rare earth metal oxide catalyst is expressed in mass percent as follows:

   Carrier alumina active component 73%～97.5%

   Copper active component 0.5%～12%

   Rare earth metal oxide active component MO _x 2% to 15%.
4. The method according to claim 2, characterized in that: the molar ratio of +1-valent Cu and zero-valent Cu in the alumina-supported copper-rare earth metal oxide catalyst satisfies the following conditions: Cu ⁰ /Cu ⁺ =1: 10～1:6.
5. The method according to any one of claims 2-4, characterized in that: the alumina-supported copper-rare earth metal oxide catalyst is prepared by a preparation method comprising the following steps: wet impregnation of copper precursor and rare earth The precursor of the metal oxide MO _x is loaded on the surface of the alumina carrier, and then the alumina carrier loaded with the precursor is calcined in air or an inert gas atmosphere (the calcining temperature is preferably 400-800 ° C), and then the calcined product is High-temperature reduction treatment is carried out at 350-500° C. (preferably 450-500° C.) in a reducing gas to finally obtain an alumina-supported copper-rare earth metal oxide catalyst.
6. The method according to claim 1, characterized in that: the catalyst II is an alumina-supported metal oxide catalyst, which includes an alumina carrier and a metal oxide active component loaded on the alumina carrier, the The active component of the metal oxide is at least one of the rare earth metal oxides; in the catalyst, the content of each component is expressed as follows in mass percent:

   Alumina carrier 80%～99.9%

   Metal oxide active components 0.1% to 20%.
7. The method according to claim 6, characterized in that: the alumina-supported metal oxide catalyst is prepared by a preparation method comprising the steps of: loading the precursor of the rare earth metal oxide to the alumina support by wet impregnation surface, and then calcining the alumina carrier loaded with the precursor in air or an inert gas atmosphere (the calcining temperature is preferably 400-800° C.), and finally an alumina-supported metal oxide catalyst is obtained.
8. The method according to claim 2 or 6, characterized in that: the alumina carrier is granular, with a specific surface of 180-450m ² /g, an average pore diameter of 1-12nm, and a pore volume of 0.3-1.5mL/g;
9. The method according to claim 2 or 6, characterized in that: the rare earth metal oxide MO _x in the catalyst I and the rare earth metal oxide in the catalyst II are each independently CeO ₂ , La ₂ O ₃ , Sm ₂ O _3. One of Sc ₂ O ₃ , Y ₂ O ₃ or a mixture of two or more in any proportion.
10. The method according to claim 1, characterized in that: said reaction is carried out continuously in a fixed-bed reactor, and said catalyst I and catalyst II are uniformly mixed and then filled in the isothermal zone of the reaction tube.

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