CN111514893A - Catalyst with sub-nanometer composite structure and preparation method thereof - Google Patents

Abstract

The invention discloses a catalyst with a sub-nano composite structure. The catalyst uses metal M as an active component, oxide _NOx as a carrier, and the active component M is dispersed on the carrier _NOx in the form of atomic clusters and single atoms respectively. . The catalyst of the present invention uses oxide _NOx as a carrier, and is loaded with atomic clusters (clusters of the same metal atom M ⁰ ) and single atoms (metal atoms M anchored by the M-O-N interface) in the form of The active component M enables the catalyst to exhibit excellent reactivity and stability in the activation of carbonyl bonds.

Description

A kind of catalyst with sub-nano composite structure and preparation method thereof

technical field

The invention relates to the technical field of catalysts, in particular to a catalyst with a sub-nano composite structure and a preparation method thereof.

Background technique

With the increasingly severe crisis of fossil energy, it is urgent to develop green renewable energy. Although biomass is a renewable resource with abundant reserves, it cannot directly replace fossil fuels due to its high oxygen content. In the chemical industry, effective activation of carbon-oxygen bonds is recognized as the most effective method to improve the quality of biomass fuels and obtain high value-added chemicals. However, the active components of current hydrogenation catalysts still rely on noble metals such as palladium, platinum, gold, and ruthenium, which severely limit their large-scale applications due to low reserves and high costs. Therefore, the development of non-precious metal catalysts with high activity and stability has an urgent application prospect.

It is well known that the activity and stability of catalysts are the two most concerned issues in industrial applications. In order to improve the catalytic efficiency, the most effective strategy is to reduce the particle size of metal catalysts from nanometers to sub-nanometers (clusters or single atoms). However, the industrialized practical application of single atoms still faces severe challenges due to the complexity of synthetic strategies, low metal loadings, and instability of atomic metals. In order to improve the stability of the catalyst, two or more different metals are usually compounded to improve the stability of the catalyst through the synergistic effect between the two or more metals. However, because it is difficult to achieve at the atomic level, it is also A tricky puzzle.

SUMMARY OF THE INVENTION

Based on the technical problems existing in the background technology, the present invention proposes a catalyst with a sub-nano composite structure and a preparation method thereof. The catalyst is supported by an oxide NO _x as a carrier and is loaded with atomic clusters (the same metal atom M ⁰ ). The active component M in the form of clusters) and single atoms (metal atoms M anchored by the MON interface) makes the catalyst exhibit excellent reactivity and stability for carbonyl bond activation.

The present invention provides a catalyst with a sub-nano composite structure. The catalyst uses metal M as an active component, oxide _NOx as a carrier, and the active component M is dispersed in the carrier _NOx in the form of atomic clusters and single atoms, respectively. superior.

Preferably, the active component M in the form of atomic clusters is a cluster of the same metal atom M ⁰ ; the active component M in the form of a single atom is the metal atom M anchored at the MON interface.

Preferably, in the catalyst, 0.5-10 wt % of the active component M is dispersed on the carrier NO _x in the form of atomic clusters, 1-49 wt % of the active component M is dispersed on the carrier NO _x in the form of single atoms, 50 -95wt% oxide _NOx as carrier.

Preferably, the metal M is a combination of one or more of copper, nickel, cobalt, iron, manganese, magnesium, and zinc; the oxide _NOx is silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, A combination of one or more of cerium oxide.

The preparation method of the above-mentioned catalyst with a sub-nano composite structure includes: performing a hydrothermal reaction on a salt of metal M and oxide NO _x to obtain a catalyst precursor; calcining and reducing the catalyst precursor in a reducing atmosphere to obtain the catalyst precursor having Catalysts with sub-nanocomposite structures.

Preferably, the temperature of the hydrothermal reaction is 80-160°C, and the time is 6-48h; the temperature of the calcination reduction reaction is preferably 200-550°C, and the time is preferably 1-12h.

Preferably, the preparation method specifically includes: adding the soluble salt of metal M and oxide NO _x into water and mixing, then adding an alkaline substance, and stirring to form a uniform emulsion; placing the emulsion in a hydrothermal reaction kettle, at 80 ℃ React at -160°C for 6-48h, filter, wash, and dry to obtain a catalyst precursor; place the catalyst precursor in a reducing atmosphere, calcine and reduce it at 200-550°C for 1-12h, to obtain the sub-nanometer composite structure catalyst.

The soluble salt of metal M and the oxide NO _x form the precursor by high temperature hydrothermal method under alkaline conditions. After calcination and reduction, part of M is reduced to form atomic clusters distributed on the surface of the catalyst. At the same time, part of M ^δ+ and NO When the bonds are connected together, they are anchored on the surface of the catalyst with the MON interface, and finally show extremely high catalytic reduction activity of carbon-oxygen bonds.

Preferably, the alkaline substance is one or more combinations of sodium hydroxide, potassium hydroxide, and ammonia;

Preferably, the filtering method is centrifugal separation, the centrifugal speed is 3000-8000rpm/min, and the centrifugal time is 3-15min; the solvent for washing is one or a combination of water, absolute ethanol and acetone The drying conditions are vacuum degree 0.01-0.1MPa, drying temperature≤90℃, drying time 6-48h; the reducing atmosphere is a gas containing hydrogen, preferably H ₂ /Ar or H with a volume ratio of 1:9 ₂ /N ₂ .

Preferably, the oxide _NOx is prepared by the following method: adding an organic alkoxide or inorganic salt containing N element to an alcohol/water mixed solvent, and performing a constant temperature reaction at 20-80° C. for 1-24 hours, and the reaction is completed. After filtering, washing, drying and calcining, the corresponding oxide NO _x is obtained.

Preferably, the oxide _NOx is prepared by the following method: adding an organic alkoxide or inorganic salt containing N element to an alcohol/water mixed solvent with a volume ratio of 1-10:1, and obtaining a concentration of 0.1 -1.0mol/L solution, react the solution at 20-80℃ for 1-24h, centrifuge with deionized water or ethanol for 3-6 times after the reaction, and then dry it at 40-90℃ for 6-24h , and then calcined at 250-850°C for 1-6h in a muffle furnace to obtain the corresponding oxide NO _x ;

Preferably, the organic alkoxide or inorganic salt containing N element is ethyl orthosilicate, methyl orthosilicate, propyl orthosilicate, butyl orthosilicate, isopropyl orthosilicate, zirconium oxynitrate , zirconium nitrate, zirconium oxychloride, zirconium sulfate, zirconium acetylacetonate, n-butyl zirconium oxide, aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum potassium sulfate dodecahydrate, titanium tetrachloride, tetrabutyl titanate, One or more combinations of tetraethyl titanate, tetraisopropyl titanate, tetraisobutyl titanate, cerium nitrate, cerium nitrate, cerium oxalate or cerium sulfate;

Preferably, the alcohol/water mixed solvent is a mixed solvent composed of ethanol or methanol and water.

The present invention also provides a method for the catalytic reduction reaction of a carbonyl-containing compound, wherein the carbonyl group of the carbonyl-containing compound is reduced to an alcoholic hydroxyl group or a methylene group under the condition of a catalyst, and the catalyst is the above-mentioned catalyst.

Preferably, the carbonyl-containing compound is an unsaturated aldehyde, ketone or carboxylic acid, preferably furfural, benzaldehyde, p-hydroxybenzaldehyde, methoxybenzaldehyde, vanillin, ethyl vanillin, cinnamaldehyde, clove one or a combination of more of the aldehydes;

The amount ratio of the catalyst to the carbonyl-containing compound is preferably (0.01-0.5): (0.03-300); the solvent of the reaction is preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tertiary One or more of butanol, cyclohexane and benzene; the temperature of the reaction is preferably 30-200°C, and the time of the reaction is preferably 5-2880min; the gas used in the reaction is preferably one of hydrogen, nitrogen and argon. One or more combinations, its body pressure is 0.2-6.5MPa.

The catalyst of the present invention performs hydrothermal reaction in an alkaline hydrothermal environment, forms a uniform compound with metal ions (M ^δ+ ) and carrier oxides (NO _x ) through slow etching, and is further treated in a reducing atmosphere to obtain a compound composed of A sub-nano composite metal catalyst formed by complexing clusters (M ⁰ ) of the same metal element with single atoms (anchored by the MON interface).

The catalyst exhibits excellent reactivity and stability in carbonyl bond activation by adjusting the interaction force between the metal and the support, combined with its unique sub-nanocomposite structure. The catalyst not only has the characteristics of small active metal size, high dispersion and high loading, but also has the advantages of safe and simple operation process, low cost, easy batch preparation, etc., and has industrial application prospects.

Description of drawings

Fig. 1 is the preparation process flow chart and transmission electron microscope picture of the catalyst described in Example 1;

Fig. 2 is the XANES spectrogram of CuO, Cu foil, _CuSiO and the catalyst described in Example 1;

Fig. ₃ is CuO, Cu foil, CuSiO3 and the EXAFS spectrum of the catalyst described in Example 1 after Fourier transformation;

Fig. 4 is the spectrogram after fitting fitting of the EXAFS spectrum of the catalyst described in Example 1;

Fig. 5 is CuSiO ₃ and the Auger electron spectrogram of the catalyst described in Example 1;

Fig. 6 is the result of hierarchical amplification catalytic reaction of vanillin directionally generating vanillin;

Fig. 7 is the result of hierarchical amplification catalytic reaction of vanillin to directionally generate 4-methylguaiacol;

Fig. 8 is the amplified catalytic reaction result of furfural directional generation of furfuryl alcohol;

Fig. 9 is the amplified catalytic reaction result of furfural directional generation of 2-methylfuran;

Fig. 10 is the amplified catalytic reaction result that cinnamaldehyde is directed to generate cinnamyl alcohol;

Figure 11 shows the results of the amplified catalytic reaction of benzaldehyde to directionally generate benzyl alcohol.

Detailed ways

Hereinafter, the technical solutions of the present invention will be described in detail through specific embodiments.

Example 1

A preparation method of a catalyst with a sub-nano composite structure, specifically comprising:

(1) 80 mL of ethanol and 25 mL of ammonia water with a concentration of 28 wt % were mixed and stirred at room temperature to obtain solution A, and then 5 mL of ethyl orthosilicate was rapidly added to solution A to obtain silica dispersion B (silicon dioxide) The particle size is 500 nm), then copper nitrate (the molar ratio of Cu and Si elements is 2:3) is added to the silica dispersion B, and after it is completely dissolved, ammonia water with a concentration of 28 wt% is added and stirred evenly A precursor solution C is obtained, and the molar ratio between copper nitrate and ammonia water (NH ₃ ·H ₂ O) in the precursor solution C is 1:10;

(2) The solution C was transferred to a reaction kettle with a polytetrafluoroethylene lining, placed in an electric heating blast drying oven at 140°C, and reacted for 24 h. The obtained product was centrifuged and washed with distilled water for several times. drying in an oven;

(3) The above-mentioned dried sample was placed in a reducing atmosphere of H ₂ /Ar with a volume ratio of 1:9, and calcined at 200° C. for 12 h to obtain the catalyst with a sub-nano composite structure, using Cu ⁰ /Cu-doped _SiO2 said.

Referring to Figures 1-5, Figure 1 shows the preparation process flow of the catalyst described in Example 1 and the characterization of its morphology and structure, wherein Figure 1(a) is the preparation process flow chart of the catalyst described in Example 1. , Figure 1(b) is the transmission electron microscope picture of the catalyst described in Example 1, Figure 1(c) is the spherical aberration corrected high-angle annular dark field scanning transmission electron microscope picture of the catalyst described in Example 1 and the corresponding energy dispersion X-ray spectroscopy (EDX), Figure 1(d) is a high-resolution transmission electron microscope image, and the corresponding Fourier transform (FFT) image is inserted in d in the form of a small image.

Figures 2-5 show the chemical state and coordination information of the catalyst described in Example 1, wherein Figure 2 is the X-ray absorption near-edge structure spectrum of CuO, Cu foil, CuSiO ₃ and the catalyst described in Example 1 (XANES ), indicating that the valence state of the copper atom of the catalyst described in Example 1 is located between Cu ⁰ (copper foil) and Cu ²⁺ (CuSiO ₃ ), and its electronic structure is Cu ^δ+ (0<δ<2), Figure 3 is the extended X-ray absorption fine structure spectrum (EXAFS) of CuO, Cu foil, _CuSiO3 and the catalyst described in Example 1, indicating that the catalyst described in Example 1 mainly exists in the form of Cu-O-Si coordination, A small part also exists in the form of Cu-Cu coordination. Figure 4 is the fitting fitting pattern of the EXAFS of the catalyst described in Example 1, which shows that the catalyst described in Example 1 has a Cu-O-Si coordination form (single atom Cu- The ratio of O-Si) to Cu-Cu coordination form (metallic copper clusters) is about 3:1, Fig. 5 is the Auger electron spectrum of the catalyst described in Example 1, which shows that Cu and _SiO2 produce The close interaction forms a new Cu-O-Si interface.

Example 2

A preparation method of a catalyst with a sub-nano composite structure, specifically comprising:

(1) 80 mL of ethanol, 20 mL of ammonia water with a concentration of 28 wt % and an appropriate amount of water were mixed and stirred at room temperature to obtain solution A, and then 6 mL of ethyl orthosilicate was rapidly added to solution A to obtain silica dispersion B (the particle size of silica is 500 nm), then add nickel sulfate (the molar ratio of Ni and Si elements is 5:4) to the silica dispersion B, and after it is completely dissolved, add a concentration of 28wt% to it. Ammonia water and stirring uniformly to obtain precursor solution C, the molar ratio between nickel sulfate and ammonia water (NH ₃ ·H ₂ O) in the precursor solution is 1:10;

(2) The precursor solution C was transferred to a reaction kettle with a polytetrafluoroethylene lining, placed in an electric heating blast drying oven at 80°C, and reacted for 12 hours. The obtained product was centrifuged and washed with distilled water for several times. , placed in an oven to dry;

(3) Take the above-mentioned dried sample and place it in a reducing atmosphere of H ₂ /N ₂ with a volume ratio of 1:9, and calcinate at 500° C. for 1 h to obtain the catalyst with the sub-nano composite structure. Ni ⁰ /Ni- doped SiO ₂ indicated.

Example 3

A preparation method of a catalyst with a sub-nano composite structure, specifically comprising:

(1) 70 mL of ethanol and 10 mL of ammonia water with a concentration of 28 wt % were mixed and stirred at room temperature to obtain solution A, and then 4 mL of n-butyl zirconium oxide was rapidly added to solution A to obtain dispersion liquid B of zirconium hydroxide. Dispersion B was centrifuged and dried, calcined at 550 °C for 5 h to obtain zirconium dioxide, and zirconium dioxide and cobalt chloride (the molar ratio of Co and Zr elements was 3:1) were added to ammonia water with a concentration of 28 wt% and stirred. uniform, to obtain a precursor solution C, and the molar ratio between cobalt chloride and ammonia water (NH ₃ ·H ₂ O) in the precursor solution C is 1:10;

(2) Transfer the precursor solution C to a reaction kettle with a polytetrafluoroethylene lining, place it in an electric heating blast drying oven at 120°C, and react for 24 hours, and the obtained product is centrifuged and washed with distilled water for several times. , placed in an oven to dry;

(3) The above-mentioned dried sample was placed in a reducing atmosphere of H ₂ /Ar with a volume ratio of 1:9, and calcined at 350° C. for 6 h to obtain the catalyst with the sub-nano composite structure, using Co ⁰ /Co-doped ZrO ₂ said.

Example 4

A preparation method of a catalyst with a sub-nano composite structure, specifically comprising:

(1) 80 mL of n-butanol and 20 mL of ammonia water (NH ₃ ·H ₂ O) with a concentration of 28 wt % were mixed and stirred at room temperature to obtain solution A, and then 4 mL of tetrabutyl titanate was rapidly added to solution A to obtain Titanium hydroxide dispersion B, the dispersion B is centrifuged and dried, calcined at 500 ° C for 6 hours to obtain titanium dioxide, titanium dioxide and ferric chloride (the molar ratio of Fe and Ti elements is 3:2) are added to the concentration of 28wt% of ammonia water and stir evenly to obtain a precursor solution C, and the molar ratio between ferric chloride and ammonia water in the precursor solution C is 1:10;

(2) The precursor solution C was transferred to a reaction kettle with a polytetrafluoroethylene lining, placed in an electric heating blast drying oven at 160°C, and reacted for 48 hours. The obtained product was centrifuged and washed with distilled water for several times. , placed in an oven to dry;

(3) The above-mentioned dried samples were placed in a reducing atmosphere of H ₂ /Ar with a volume ratio of 1:9, and calcined at 550° C. for 4 hours to obtain the catalyst with the sub-nano composite structure, using Fe ⁰ /Fe-doped _TiO2 said.

The catalyst Cu ⁰ /Cu-doped SiO ₂ described in the above Example 1 was used for the carbonyl activation reduction reaction of vanillin. Specifically, the catalyst prepared in Example 1 was added to the reaction kettle, and then vanillin and the reaction solvent were added. , charged with hydrogen or nitrogen, and reacted in a hydrogen or nitrogen atmosphere to obtain the corresponding product. The consumption of reaction raw materials is 0.03-300g, the consumption of catalyst is 0.01-0.5g respectively, and the reaction solvent is methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, cyclohexane or benzene , the reaction temperature is 30-200°C, the gas pressure is 0.2-6.5MPa, and the reaction time is 5-2880min. The results are shown in Figures 6 and 7. In Figures 6 and 7, the amount of catalyst corresponding to 10mmol of reaction raw materials is 0.04g , the catalyst dosage corresponding to 40mmol of reaction raw materials is 0.15g.

The catalyst Ni ⁰ /Ni-doped SiO ₂ described in the above Example 2 was used for the carbonyl activation reduction reaction of furfural. Specifically, the catalyst prepared in Example 2 was added to the reaction kettle, then furfural and the reaction solvent were added, and hydrogen was charged. Or nitrogen, the reaction is carried out under hydrogen or nitrogen atmosphere to obtain the corresponding product. The consumption of the reaction raw materials is 0.03-300g, the consumption of the catalyst is 0.01-0.5g, and the reaction solvent is water, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, cyclohexane or Benzene, the reaction temperature is 30-200°C, the gas pressure is 0.2-6.5MPa, and the reaction time is 5-2880min. The results are shown in Figures 8 and 9. In Figures 8 and 9, the amount of catalyst used is 0.15g, and the gas pressure is 0.15g. is 4MPa.

The catalyst Co ⁰ /Co-doped ZrO ₂ described in the above Example 3 was used for the carbonyl activation reduction reaction of cinnamaldehyde. Specifically, the catalyst prepared in Example 3 was added to the reaction kettle, and then the cinnamaldehyde and the reaction solvent were added. Introduce hydrogen or nitrogen, and carry out the reaction under the atmosphere of hydrogen or nitrogen to obtain the corresponding product. The consumption of reaction raw materials is 0.03-300g, the consumption of catalyst is 0.01-0.5g, and the reaction solvent is methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, cyclohexane or benzene, The reaction temperature is 30-200°C, the gas pressure is 0.2-6.5MPa, and the reaction time is 5-2880min. The results are shown in Figure 10. In Figure 10, the catalyst dosage is 0.15g and the gas pressure is 0.5MPa.

The catalyst Fe ⁰ /Fe-doped TiO ₂ described in the above-mentioned Example 4 was used for the carbonyl activation reduction reaction of benzaldehyde. Specifically, the catalyst prepared in Example 4 was added to the reaction kettle, and then benzaldehyde and the reaction solvent were added to fill it. Introduce hydrogen or nitrogen, and carry out the reaction under the atmosphere of hydrogen or nitrogen to obtain the corresponding product. The consumption of reaction raw materials is 0.03-300g, the consumption of catalyst is 0.01-0.5g, and the reaction solvent is methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, cyclohexane or benzene, The reaction temperature is 30-200°C, the gas pressure is 0.2-6.5MPa, and the reaction time is 5-2880min. The results are shown in Figure 11. In Figure 11, the catalyst dosage is 0.15g and the gas pressure is 6MPa.

The above is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Equivalent replacement or modification of the invention shall be included within the protection scope of the present invention.

Claims (10)

1. The catalyst with a sub-nanometer composite structure is characterized in that the catalyst takes metal M as an active component and oxide NO_xAs carrier, active component M is respectively dispersed in the form of atom cluster and single atom in carrier NO_xThe above.

2. The catalyst with sub-nanocomposite structure according to claim 1, wherein the active component M in the form of atomic clusters is the same metal atom M⁰(ii) clusters of (a); the active component M existing in the form of a single atom is a metal atom M anchored by an M-O-N interface.

3. Catalyst with sub-nanocomposite structure according to claim 1 or 2, characterized in that in the catalyst 0.5-10 wt% of active component M is dispersed in the form of atomic clusters in the carrier NO_xFrom 1 to 49% by weight of active ingredient M are dispersed in the form of a single atom in the carrier NO_x50-95 wt% of oxide NO_xIs a carrier.

4. The catalyst with a sub-nanocomposite structure according to any one of claims 1 to 3, wherein the metal M is one or a combination of more of copper, nickel, cobalt, iron, manganese, magnesium, zinc; oxide NO_xIs one or the combination of more of silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide and cerium dioxide.

5. A method for preparing a catalyst having a sub-nanocomposite structure according to any one of claims 1 to 4, comprising: by reacting salts and oxides of metals M NO_xCarrying out hydrothermal reaction to obtain a catalyst precursor; and calcining and reducing the catalyst precursor in a reducing atmosphere to obtain the catalyst with the sub-nano composite structure.

6. The method for preparing a catalyst with a sub-nano composite structure according to claim 5, wherein the temperature of the hydrothermal reaction is 80-160 ℃ and the time is 6-48 h; the temperature of the calcination reduction reaction is preferably 200-550 ℃, and the time is preferably 1-12 h.

7. Process for the preparation of a catalyst with a sub-nanocomposite structure according to any of claims 5 to 6The preparation method is characterized by comprising the following steps: by reacting soluble salts of metal M with oxides NO_xAdding water, mixing, adding alkaline substance, and stirring to obtain uniform emulsion; putting the emulsion into a hydrothermal reaction kettle for reaction, filtering, washing and drying to obtain a catalyst precursor; placing the catalyst precursor in a reducing atmosphere for calcination and reduction to obtain the catalyst with the sub-nano composite structure;

preferably, the alkaline substance is one or more of sodium hydroxide, potassium hydroxide and ammonia water; the washing solvent is one or a combination of water, absolute ethyl alcohol and acetone; the reducing atmosphere is a gas containing hydrogen, preferably H in a volume ratio of 1:9₂/Ar or H₂/N₂。

8. Process for the preparation of a catalyst with a sub-nanocomposite structure according to any of claims 5 to 7, characterised in that the oxide NO is_xThe preparation method comprises the following steps: adding organic alkoxide or inorganic salt containing N element into alcohol/water mixed solvent for constant temperature reaction, filtering, washing, drying and calcining to obtain corresponding oxide NO_x；

Preferably, the organic alkoxide or inorganic salt containing N element is one or a combination of more of ethyl orthosilicate, methyl orthosilicate, propyl orthosilicate, butyl orthosilicate, isopropyl orthosilicate, zirconyl nitrate, zirconium oxychloride, zirconium sulfate, zirconium acetylacetonate, aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum potassium sulfate dodecahydrate, titanium tetrachloride, tetrabutyl titanate, tetraethyl titanate, tetraisopropyl titanate, tetraisobutyl titanate, cerium nitrate, cerous nitrate, cerium oxalate or cerium sulfate; the alcohol/water mixed solvent is a mixed solvent composed of ethanol or methanol and water.

9. A method for catalytic reduction of a carbonyl group-containing compound, wherein the carbonyl group of the carbonyl group-containing compound is reduced to an alcoholic hydroxyl group or a methylene group under the condition of a catalyst, wherein the catalyst is the catalyst according to any one of claims 1 to 4 or the catalyst prepared by the preparation method according to any one of claims 5 to 8.

10. The method for catalytic reduction reaction of carbonyl compound according to claim 9, characterized in that, the carbonyl compound is unsaturated aldehyde, ketone or carboxylic acid, preferably furfural, benzaldehyde, p-hydroxybenzaldehyde, methoxybenzaldehyde, vanillin, ethyl vanillin, cinnamaldehyde, syringaldehyde or one or more combinations thereof;

the dosage ratio of the catalyst to the carbonyl-containing compound is preferably (0.01-0.5) to (0.03-300); the solvent for reaction is preferably one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, cyclohexane and benzene; the reaction temperature is preferably 30-200 ℃, and the reaction time is preferably 5-2880 min; the gas used in the reaction is preferably one or the combination of more of hydrogen, nitrogen and argon, and the gas pressure is 0.2-6.5 MPa.

Images