Method for synthesizing 4-hydroxycyclopentyl-2-ketene by using copper-based bimetallic oxide to catalyze rearrangement of furfuryl alcohol

Abstract

The invention discloses a method for synthesizing 4-hydroxycyclopentyl-2-ketene by catalyzing rearrangement of furfuryl alcohol with a copper-based bimetallic oxide, which is characterized in that under the action of a copper-based composite metal oxide catalyst, furfuryl alcohol is subjected to one-step conversion in a stainless steel autoclave to generate a target product 4-hydroxycyclopentyl-2-ketene, wherein the heterogeneous catalyst is a CuX type composite bimetallic oxide, X is selected from one of La, Bi, Fe, Ce, Ga and Cr, and the theoretical atomic number ratio of Cu to X is (1-5): 1. And a novel, simple and efficient synthesis method is provided for the preparation of the renewable 4-hydroxycyclopentyl-2-ketene.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical preparation, and particularly relates to a method for synthesizing 4-hydroxycyclopent-2-enone by the rearrangement of furfuryl alcohol catalyzed by a copper-based bimetallic oxide. Background Art

[0002] 4-Hydroxycyclopent-2-enone is an α,β-unsaturated carbonyl compound, an organic compound with a special structure and high reactivity. It can be used as a monomer for unsaturated polymers and is used in the synthesis of other organic materials such as polymer materials. It is also an important component of pharmaceutically relevant compounds and an important precursor of many natural products. These compounds have wide application values in the fields of fine chemicals, medicine, pesticides, etc. Therefore, the synthesis of 4-hydroxycyclopent-2-enone is a hot topic in organic chemistry research. Unfortunately, the production capacity of 4-hydroxycyclopent-2-enone is very limited and far from meeting the application requirements in various fields. Therefore, it is of great significance to find new technologies for synthesizing renewable 4-hydroxycyclopent-2-enone using bulk chemicals as raw materials.

[0003] Biomass is the only renewable resource that can replace fossil raw materials to produce liquid fuels and bulk organic chemicals. Its development and utilization are of great significance for reducing dependence on fossil energy, cutting greenhouse gas emissions, and promoting sustainable development. In recent years, people have been making increasing efforts to establish new technologies for converting biomass into fuels or basic chemicals, which can be further used to produce fine chemicals, materials, or pharmaceuticals. Furfuryl alcohol is an important biomass platform compound, and many schemes have been developed for the conversion of furfuryl alcohol into 4-hydroxycyclopent-2-enone. For example, the research group of Hronec reported that furfuryl alcohol can be converted into 4-hydroxycyclopent-2-enone (HCP) under the catalysis of hydrogen protons formed by the self-dissociation of water at 180 - 200 °C (Journal of Industrial and Engineering Chemistry, 2014, 20(2): 650 - 655.). Unfortunately, the yield of HCP is very low (i.e., about 50%).

[0004] Zhang's team used catalysts such as sodium hydroxide, sodium carbonate, or calcium oxide to reduce the concentration of hydrogen protons generated in situ by water at 240 °C (Green Chemistry, 2016, 18(12): 3607 - 3613). Although the conversion rate of furfuryl alcohol decreased, the selectivity of HCP increased, and the yield of HCP was about 80%. However, the reaction temperature (240 °C) and energy consumption in this work are relatively high, and the concentration of furfuryl alcohol in the reaction is low (10 wt.%), which is not conducive to production in practical applications.

[0005] Zou's team synthesized a pure solid Lewis acid catalyst. At 150 °C, in a water / n-hexane biphasic solvent system, the rearrangement reaction of furfuryl alcohol was carried out (Green Chemistry, 2020, 22(8): 2549-2557), and the yield of HCP was about 85%. However, in this work, the concentration of furfuryl alcohol in the system was also very low (about 5 wt.%), and there were disadvantages such as a complex catalyst preparation process, expensive catalyst materials, and high costs. Since some polymers were easily formed during the reaction process, this phenomenon became more serious as the concentration of furfuryl alcohol in the system gradually increased, resulting in a gradual decrease in the yield of the target product - 4-hydroxycyclopent-2-enone. Summary of the Invention

[0006] In view of the above technical problems, the present invention provides a method for synthesizing 4-hydroxycyclopent-2-enone by the rearrangement of furfuryl alcohol catalyzed by a copper-based bimetallic oxide. Under the action of a copper-based composite metal oxide catalyst, furfuryl alcohol is directly converted into the target product - 4-hydroxycyclopent-2-enone in a stainless steel autoclave, providing a new, simple and efficient synthesis method for the preparation of renewable 4-hydroxycyclopent-2-enone.

[0007] The present invention is achieved by the following technical solutions:

[0008] The present invention provides a method for synthesizing 4-hydroxycyclopent-2-enone by the rearrangement of furfuryl alcohol catalyzed by a copper-based bimetallic oxide. The method is as follows: Using furfuryl alcohol as a raw material, under the promotion of a heterogeneous catalyst, an aqueous phase rearrangement reaction occurs to selectively obtain the 4-hydroxycyclopent-2-enone; wherein the heterogeneous catalyst is a CuX type composite bimetallic oxide, X is selected from one of La, Bi, Fe, Ce, Ga, Cr, and the theoretical atomic ratio of Cu / X is 1-5:1.

[0009] The chemical structural formulas of the raw material furfuryl alcohol and the target product 4-hydroxycyclopent-2-enone are shown in Table 1

[0010]

[0011] The reaction path of the present invention is as follows:

[0012]

[0013] Further, in the above technical solution, the reaction is carried out in a batch reactor. Water and the copper-based composite oxide catalyst are placed in a stainless steel autoclave. The dosage ratio of water to the catalyst is 20,000 - 2,000:1; (preferably 20,000 - 4,000:1, more preferably 8,000 - 5,000:1). The air in the reactor is removed (the reactor is purged with nitrogen 6 times). The reaction temperature is 160 - 240 °C (preferably 190 - 235 °C, more preferably 200 - 220 °C). The concentration of the furfuryl alcohol aqueous solution is 10 wt.% - 50 wt.% (preferably 10 wt.% - 40 wt.%, more preferably 10 wt.% - 30 wt.%). The reaction time is 4 - 5 minutes.

[0014] Further, in the above technical solution, the CuX type composite double metal oxide is selected from oxides of CuLa, CuBi, CuFe, CuCe, CuGa, and CuCr. The theoretical atomic number ratio of Cu / X is preferably 1 - 4:1; more preferably 1 - 3:1.

[0015] Further, in the above technical solution, the CuX type composite metal oxide catalyst uses Cu(NO3)2·3H2O and La(NO3)3·6H2O, Bi(NO3)3·5H2O, Fe(NO3)3·9H2O, Ce(NO3)3·6H2O, Ga(NO3)3·9H2O, or Cr(NO3)3·9H2O as precursors, and a double metal mixed oxide is synthesized by the co-precipitation method. Their theoretical atomic number ratio of Cu / X is 1 - 5:1, (preferably 1 - 4:1; more preferably 1 - 3:1).

[0016] Further, in the above technical solution, the CuX type composite metal oxide is prepared by the deposition-precipitation method.

[0017] The specific process is as follows: The copper nitrate and X nitrate solutions are mixed according to the range of the theoretical atomic number ratio. The concentration of copper nitrate in the mixed solution is 1 - 5 mol / L, and the concentration of the X nitrate solution is 1 mol / L. Then, the mixed solution is slowly dropped into 2 mol / L sodium carbonate or an aqueous solution of sodium carbonate and sodium hydroxide at 30 - 110 °C (preferably 40 - 100 °C, more preferably 50 - 90 °C) (the volume ratio of the mixed solution to the sodium carbonate or the mixed aqueous solution of sodium carbonate and sodium hydroxide is 1:1). Under the condition of controlling the pH value to be 9 - 12, rapid stirring is carried out, and the pH is adjusted by continuously adding 1 mol / L precipitant Na2CO3 or NaOH solution. Aging is carried out at 70 - 90 °C for 18 - 24 hours, drying is carried out in an oven at 80 - 200 °C for 4 - 48 hours, and then calcination is carried out at 300 - 800 °C (preferably 350 - 750 °C, more preferably 400 - 700 °C) for 0.5 - 10 hours (preferably 1 - 8 hours, more preferably 1 - 6 hours) to obtain the CuX type double metal composite metal oxide catalyst.

[0018] X nitrate is selected from one of La(NO3)3·6H2O, Bi(NO3)3·5H2O, Fe(NO3)3·9H2O, Ce(NO3)3·6H2O, Ga(NO3)3·9H2O and Cr(NO3)3·9H2O.

[0019] Furthermore, in the above technical solution, the ratio of the amount of the heterogeneous catalyst to the solvent water is 2 mg - 14 mg: 40 g; (preferably 2 mg - 11 mg, more preferably 5 mg - 8 mg). The air in the reactor is removed with nitrogen, the reaction temperature is 160 - 240 °C (preferably 190 - 235 °C, more preferably 200 - 220 °C), the concentration of the furfuryl alcohol aqueous solution is 10 wt.% - 50 wt.% (preferably 10 wt.% - 40 wt.%, more preferably 10 wt.% - 30 wt.%), and the reaction time is 4 - 5 min.

[0020] The present invention uses a CuX-type composite double metal oxide catalyst to carry out the reaction at a lower temperature (200 °C) and a higher initial concentration of furfuryl alcohol (20 wt.%), and the yield of the target product 4-hydroxycyclopent-2-enone (90%) is significantly higher than the previously reported. It provides a new, simple and efficient synthesis method for the one-step preparation of 4-hydroxycyclopent-2-enone from furfuryl alcohol.

[0021] The beneficial effects that this application can produce include:

[0022] 1. The method introduced in the present invention is easy to operate, can directly synthesize 4-hydroxycyclopent-2-enone from furfuryl alcohol in one step through an aqueous-phase reaction, constituting an environmentally friendly and efficient synthesis route. In addition, the catalyst preparation process adopted is simple, the reaction conditions are mild, and it has good stability. This method not only achieves a high conversion rate of furfuryl alcohol but also ensures excellent selectivity for 4-hydroxycyclopent-2-enone, so it is suitable for large-scale industrial production applications.

[0023] 2. The present invention uses a stainless-steel batch reactor, and under the action of the catalyst, it realizes the one-step direct conversion of furfuryl alcohol to 4-hydroxycyclopent-2-enone. It has multiple advantages such as a simple process route, mild reaction conditions, and environmental friendliness.

[0024] 3. The present invention innovatively designs and prepares a series of CuX-type composite metal oxide catalysts for the efficient conversion of furfuryl alcohol into high-value-added 4-hydroxycyclopent-2-enone. When the aqueous-phase rearrangement reaction occurs at a constant temperature, this catalyst can promote the reaction to be directly completed in one step. Compared with previous reports, this method not only increases the concentration of furfuryl alcohol in the reaction system but also significantly improves its conversion rate and the yield of the target product. Under the optimal conditions, the conversion rate of furfuryl alcohol can exceed 96%, and the yield of 4-hydroxycyclopent-2-enone can also reach over 90%. This achievement demonstrates good catalytic performance and has the potential for actual industrial production. Description of the Drawings

[0025] Figure 1 It is the liquid chromatogram of the products of synthesizing 4-hydroxycyclopent-2-enone from furfuryl alcohol in Example 2 and Example 7.

[0026] Figure 2 It is the mass spectrometry control chart of the target product 4-hydroxycyclopent-2-enone obtained in Example 7. Detailed Description of the Invention

[0027] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0028] Example 1

[0029] (1) Preparation of the solid base CuLa catalyst: 20 mL of Cu(NO3)2·3H2O (14.5051 g) and La(NO3)3·6H2O (8.6588 g) nitrate solutions (3 mol / L and 1 mol / L respectively) were dropped into 20 mL of distilled water containing 2 mol / L Na2CO3 (4.2384 g). Stir rapidly under the condition of a constant pH value of 10, and adjust the pH by continuously adding 1 mol / L NaOH solution. The obtained gel was aged at 80 °C for 24 hours, then centrifuged, and the solid was washed with distilled water until the pH of the filtrate was neutral. The obtained product was dried in an oven at 70 °C for 24 hours, and then calcined at 500 °C for 3 hours in an air atmosphere.

[0030] (2) Put 5 mg of the above CuLa catalyst and 40 g of water into a stainless-steel autoclave. The reactor was purged with nitrogen 6 times, and the reaction temperature was 200 °C. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL / min), 20 mL of an aqueous solution of furfuryl alcohol with a concentration of 20 wt.% was injected into the reactor. The reaction time was 5 minutes. After the reaction ended, the heating was turned off, and the temperature was rapidly cooled with cold water to reduce the temperature of the reaction kettle to about 50 °C. The product and the catalyst were separated by filtration. Based on the quantitative results of gas chromatography, the conversion rate of furfuryl alcohol was 100%, and the yield of 4-hydroxycyclopent-2-enone was 90%.

[0031] Example 2

[0032] (1) Preparation of solid base CuBi catalyst: 20 mL of Cu(NO3)2·3H2O (14.4963 g) and Bi(NO3)3·5H2O (9.7020 g) nitrate solutions (3 mol / L and 1 mol / L respectively) were dropped into 20 mL of an aqueous solution of 2 mol / L Na2CO3 (4.2384 g). Rapid stirring was carried out under the condition of a constant pH value of 10, and the pH was adjusted by continuously adding 1 mol / L NaOH aqueous solution. The obtained gel was aged at 80 °C for 24 hours, then centrifuged, and the solid was washed with distilled water until the pH of the filtrate was neutral. The obtained product was dried in an oven at 70 °C for 24 hours, and then calcined at 500 °C for 3 hours in an air atmosphere.

[0033] (2) 5 mg of the above CuBi catalyst and 40 g of water were placed in a stainless-steel autoclave. The reactor was purged with nitrogen 6 times, and the reaction temperature was 200 °C. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL / min), 20 mL of an aqueous solution of furfuryl alcohol with a concentration of 20 wt.% was injected into the reactor. The reaction time was 5 minutes. After the reaction, the heating was turned off, and the temperature was rapidly decreased with cold water to lower the temperature of the autoclave to about 50 °C. The product and the catalyst were separated by filtration. Based on the quantitative results of gas chromatography, the conversion rate of furfuryl alcohol was 99%, and the yield of 4-hydroxycyclopent-2-enone was 69%.

[0034] Example 3

[0035] (1) Preparation of solid base CuFe catalyst: 20 mL of Cu(NO3)2·3H2O (14.4968 g) and Fe(NO3)3·9H2O (8.0822 g) nitrate solutions (3 mol / L and 1 mol / L respectively) were dropped into 20 mL of an aqueous solution of 2 mol / L Na2CO3 (4.2384 g). Rapid stirring was carried out under the condition of a constant pH value of 10, and the pH was adjusted by continuously adding 1 mol / L NaOH aqueous solution. The obtained gel was aged at 80 °C for 24 hours, then centrifuged, and the solid was washed with distilled water until the pH was neutral. The obtained product was dried in an oven at 70 °C for 24 hours, and then calcined at 500 °C for 3 hours in an air atmosphere.

[0036] (2) 5 mg of the above CuFe catalyst and 40 g of water were placed in a stainless-steel autoclave. The reactor was purged with nitrogen 6 times, and the reaction temperature was 200 °C. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL·min -1) 20 mL of an aqueous furfuryl alcohol solution with a concentration of 20 wt.% was injected into the reactor. The reaction time was 5 minutes. After the reaction, heating was turned off and the temperature was rapidly decreased with cold water until the temperature of the reaction kettle dropped to about 50 °C. The product and the catalyst were separated by filtration. Based on the quantitative results of gas chromatography, the conversion rate of furfuryl alcohol was 96%, and the yield of 4-hydroxycyclopent-2-enone was 79%.

[0037] Example 4

[0038] (1) Preparation of the solid base CuCe catalyst: 20 mL of Cu(NO3)2·3H2O (14.5001 g) and Ce(NO3)3·6H2O (8.6850 g) nitrate solutions (3 mol / L and 1 mol / L respectively) were dropped into 20 mL of an aqueous solution of 2 mol / L Na2CO3 (4.2384 g). Rapid stirring was carried out under the condition of a constant pH value of 10, and the pH was adjusted by continuously adding 1 mol / L NaOH solution. The obtained gel was aged at 80 °C for 24 hours, then centrifuged, and the solid was washed with distilled water until the pH of the filtrate was neutral. The obtained product was dried in an oven at 70 °C for 24 hours, and then calcined at 500 °C for 3 hours in an air atmosphere.

[0039] (2) 5 mg of the above CuCe catalyst and 40 g of water were placed in a stainless-steel autoclave. The reactor was purged with nitrogen 6 times, and the reaction temperature was 200 °C. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL·min -1 ) 20 mL of an aqueous furfuryl alcohol solution with a concentration of 20 wt.% was injected into the reactor. The reaction time was 5 minutes. After the reaction, heating was turned off and the temperature was rapidly decreased with cold water until the temperature of the reaction kettle dropped to about 50 °C. The product and the catalyst were separated by filtration. Based on the quantitative results of gas chromatography, the conversion rate of furfuryl alcohol was 98%, and the yield of 4-hydroxycyclopent-2-enone was 73%.

[0040] Example 5

[0041] (1) Preparation of the solid base CuGa catalyst: 20 mL of Cu(NO3)2·3H2O (14.5008 g) and Ga(NO3)3·9H2O (5.1148 g) nitrate solutions (3 mol / L and 1 mol / L respectively) were dropped into 20 mL of an aqueous solution of 2 mol / L Na2CO3 (4.2384 g). Rapid stirring was carried out under the condition of a constant pH value of 10, and the pH was adjusted by continuously adding 1 M NaOH solution. Once the gel was obtained, it was aged at 80 °C for 24 hours, then centrifuged, and the solid was washed with distilled water until the pH was neutral. The obtained product was dried in an oven at 70 °C for 24 hours, and then calcined at 500 °C for 3 hours in an air atmosphere.

[0042] (2) Put 5 mg of the above CuGa catalyst and 40 g of water into a stainless-steel autoclave. The reactor was purged with nitrogen 6 times, and the reaction temperature was 200 °C. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL / min), 20 mL of an aqueous furfuryl alcohol solution with a concentration of 20 wt.% was injected into the reactor. The reaction time was 5 minutes. After the reaction, turn off the heating and rapidly cool with cold water to lower the temperature of the autoclave to about 50 °C, and separate the product from the catalyst by filtration. Based on the gas chromatography quantitative results, the conversion rate of furfuryl alcohol was 98%, and the yield of 4-hydroxycyclopent-2-enone was 68%.

[0043] Example 6

[0044] (1) Preparation of the solid base CuCr catalyst: Drop 20 mL of Cu(NO3)2·3H2O (14.4978 g) and Cr(NO3)3·9H2O (4.7662 g) nitrate solutions (3 mol / L and 1 mol / L respectively) into 20 mL of an aqueous solution containing 2 mol / L Na2CO3 (4.2384 g). Stir rapidly under the condition of a constant pH value of 10, and adjust the pH by continuously adding 1 mol / L NaOH solution. The obtained gel was aged at 80 °C for 24 hours, then centrifuged, and the solid was washed with distilled water until the pH was neutral. The obtained product was dried in an oven at 70 °C for 24 hours, and then calcined at 500 °C in an air atmosphere for 3 hours.

[0045] (2) Put 5 mg of the above CuCr catalyst and 40 g of water into a stainless-steel autoclave. The reactor was purged with nitrogen 6 times, and the reaction temperature was 200 °C. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL / min), 20 mL of an aqueous furfuryl alcohol solution with a concentration of 20 wt.% was injected into the reactor. The reaction time was 5 minutes. After the reaction, turn off the heating and rapidly cool with cold water to lower the temperature of the autoclave to about 50 °C, and separate the product from the catalyst by filtration. Based on the gas chromatography quantitative results, the conversion rate of furfuryl alcohol was 100%, and the yield of 4-hydroxycyclopent-2-enone was 67%. As can be seen from Table 2, the best effect is achieved when the CuLa catalyst is used. The reason is that the copper and lanthanum bimetallic oxides form specific active centers during the reaction, with a unique electronic structure, which is conducive to the adsorption and activation of furfuryl alcohol molecules. At the same time, the CuLa catalyst surface has Lewis acidic sites, which can promote the protonation of furfuryl alcohol molecules and is beneficial to the rearrangement reaction.

[0046] Table 2 Performance of different catalysts for the aqueous-phase rearrangement of furfuryl alcohol to 4-hydroxycyclopent-2-enone

[0047]

[0048] Examples 7 - 10

[0049] Using CuLa in Example 1 as the catalyst, 5 mg of the CuLa catalyst and 40 g of water were placed into a stainless-steel autoclave. The reactor was purged with nitrogen 6 times. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL / min), 20 mL of an aqueous furfuryl alcohol solution with a concentration of 20 wt.% was injected into the reactor. The reaction time was 5 minutes. The results at different reaction temperatures were tested. As shown in Table 3, when the reaction temperature was 200 °C, a better effect was obtained.

[0050] Table 3 Effect of reaction temperature on the rearrangement of furfuryl alcohol to 4-hydroxycyclopent-2-enone catalyzed by CuLa

[0051]

[0052]

[0053] Examples 11 - 14

[0054] Using CuLa in Example 1 as the catalyst, 5 mg of the CuLa catalyst and 40 g of water were placed into a stainless-steel autoclave. The reactor was purged with nitrogen 6 times. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL / min), 20 mL of an aqueous furfuryl alcohol solution was injected into the reactor at a reaction temperature of 200 °C and a reaction time of 5 minutes. The results under different concentrations of the aqueous furfuryl alcohol solution were tested. As shown in Table 4.

[0055] Table 4 Effect of initial concentration on the rearrangement of furfuryl alcohol to 4-hydroxycyclopent-2-enone catalyzed by CuLa

[0056]

[0057] Examples 15 - 20

[0058] Using CuLa in Example 1 as the catalyst, a certain amount of the catalyst and 40 g of water were placed into a stainless-steel autoclave. The reactor was purged with nitrogen 6 times. Using an HPLC pump (feeding time 2 minutes, feeding rate 10 mL / min), 20 mL of an aqueous furfuryl alcohol solution with a concentration of 20 wt.% was injected into the reactor. The reaction temperature was 200 °C and the reaction time was 5 minutes. As shown in Table 5, when the catalyst dosage was 5 mg, the best effect was obtained.

[0059] Table 5 Effect of catalyst dosage on the rearrangement of furfuryl alcohol to 4-hydroxycyclopent-2-enone catalyzed by CuLa

[0060]

[0061] As can be seen from the above embodiments, using furfuryl alcohol as a raw material, through an aqueous-phase rearrangement reaction, 4-hydroxycyclopent-2-enone with high added value can be directly synthesized in one step. Moreover, the concentration (20 wt.%) and yield (90%) of furfuryl alcohol in the system are both higher than those reported previously. At the same time, the conversion rate of furfuryl alcohol can reach more than 96%, and there are additional advantages such as simple preparation method of the catalyst, mild reaction conditions, and good stability. This makes this application conducive to industrial production and has practicality.

Claims

1. A method for synthesizing 4-hydroxycyclopent-2-enone by rearrangement of furfuryl alcohol catalyzed by copper-based bimetallic oxides, characterized in that: The method is as follows: Furfuryl alcohol is used as a raw material, and the 4-hydroxycyclopent-2-enone is selectively obtained through an aqueous phase rearrangement reaction under the promotion of a multiphase catalyst; wherein the multiphase catalyst is a CuX type composite bimetallic oxide, X is selected from one of La, Bi, Fe, Ce, Ga, and Cr, and the theoretical atomic ratio of Cu / X is 1 to 5:

1.

2. The method according to claim 1, characterized in that: The reaction is carried out in a batch reactor, water and a multiphase catalyst are placed in a stainless steel autoclave; air in the reactor is removed with an inert gas before the reaction, the reaction temperature is 160-240° C., the concentration of the furfuryl alcohol aqueous solution is 10wt.%-50wt.%, and the reaction time is 4-5 minutes.

3. The method according to claim 1 or 2, characterized in that: The CuX type composite bimetallic oxide is selected from the oxides of CuLa, CuBi, CuFe, CuCe, CuGa and CuCr, and the theoretical atomic ratio of Cu / X is 1 to 4:

1.

4. The method according to claim 1, characterized in that: The CuX type composite bimetallic oxide catalyst uses Cu(NO3)2·3H2O and La(NO3)3·6H2O, Bi(NO3)3·5H2O, Fe(NO3)3·9H2O, Ce(NO3)3·6H2O, Ga(NO3)3·9H2O or Cr(NO3)3·9H2O as precursors, and synthesizes the bimetallic mixed oxide by co-precipitation method, and the theoretical atomic ratio of Cu / X is 1 to 5:

1.

5. The method according to claim 1, characterized in that: CuX type composite bimetallic oxide catalyst was prepared by deposition precipitation method. The specific process is as follows: according to the theoretical atomic ratio range of Cu / X, copper nitrate and other metal nitrate solutions are mixed; the atomic ratio of Cu to X in the mixed solution is 1 to 5:1, and then the mixed solution is slowly dripped into sodium carbonate or sodium carbonate and sodium hydroxide aqueous solution at 30 to 110°C, and rapidly stirred under the condition of controlling the pH value to be 9 to 12, and the pH is adjusted by continuously adding 1 mol / L precipitant Na2CO3 or NaOH solution, and the pH is maintained between 9 and 12; aging at 70 to 90°C for 18 to 24 hours, drying in an oven at 80 to 200°C for 4 to 48 hours, and then calcining at 300 to 800°C for 0.5 to 10 hours to obtain a CuX type composite bimetallic oxide catalyst.

6. The method according to claim 1, characterized in that: The ratio of the amount of the multiphase catalyst to the solvent water is 2mg-14mg:40g.

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