Hydrodeoxygenation catalyst, method for preparing same, and use thereof

Abstract

The application discloses a hydrodeoxygenation catalyst and a preparation method and application thereof, and the hydrodeoxygenation catalyst comprises a carrier and an active component, wherein gamma-Al2O3 modified by Nb2O5 is used as the carrier, and metal Fe and Ni are used as the active component. The application promotes the interaction between the Ni-Fe active component and the surface of the carrier through Nb2O5 modification, thereby preventing the phenomenon of active component loss in the reaction process, improving the stability of the catalyst, and promoting the electronic interaction between the Ni-Fe active component and the carrier after the Nb2O5 modification, thereby improving the catalytic performance of the catalyst. The gamma-Al2O3 composite carrier modified by Nb2O5 is a carrier with both acidity and good stability, and the bimetallic catalyst can well control the morphology and electronic structure of the main metal due to the introduction of the second metal, thereby improving the catalytic performance of the bimetallic catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a hydrodeoxygenation catalyst, a preparation method and application thereof. BACKGROUND

[0002] With the development of society, the large consumption of non-renewable energy leads to environmental pollution and energy crisis. Finding renewable energy to replace non-renewable energy is the focus of current researchers. Bio-oil obtained by biomass pyrolysis is a sustainable and green raw material, which has attracted the attention of many researchers. However, due to the characteristics of high viscosity, low combustion value and strong corrosion of bio-oil derived from biomass, these will limit its wide application in industry. Catalytic hydrodeoxygenation is an effective way to improve the quality of bio-oil. Guaiacol has three different C-O bonds (Caryl-OH, Calkyl-OAr, and Caryl-OCH3), and is a typical biomass platform compound. Through the hydrodeoxygenation of guaiacol, a series of high value-added chemicals such as benzene, phenol, cyclohexanol and cyclohexane can be prepared, among which cyclohexanol is a bulk chemical that can be used to prepare adipic acid, caprolactam, perfumes, drugs, polymers, plasticizers, etc. The reaction process of preparing cyclohexanol by hydrodeoxygenation of guaiacol is challenging, as it involves aromatic ring hydrogenation and selective removal of oxygen-containing functional groups. Therefore, the key to preparing cyclohexanol by hydrodeoxygenation of guaiacol lies in the preparation of a high-performance hydrodeoxygenation catalyst.

[0003] Traditional metal sulfide catalysts (such as MoS, CoMoS and NiMoS) are used in the hydrodeoxygenation reaction of guaiacol. Such catalysts show good catalytic activity and selectivity, but the reaction system requires harsh reaction conditions, and the poor structural stability of such catalysts leads to poor catalyst cycle life. In recent years, researchers have developed noble metal catalysts (such as Pt, Pd and Ru) for guaiacol hydrodeoxygenation reactions. Noble metal catalysts exhibit excellent catalytic activity, but their high cost and scarcity greatly limit their widespread application in industry. Therefore, finding a low-cost, high-activity, high-selectivity and high-stability catalyst for guaiacol catalytic hydrodeoxygenation to prepare cyclohexanol has attracted widespread attention. Although ordinary nickel-carbon catalysts are low in cost, the lack of acid sites in the catalyst leads to poor deoxygenation activity during the reaction, and the catalyst stability is also poor.

[0004] A patent (CN115672377A) discloses a nitrogen-doped carbon-supported cobalt catalyst and is used in a guaiacol hydrodeoxygenation reaction to prepare cyclohexanol, although good catalytic effect can be achieved, the preparation cost of the catalyst is high and the catalyst yield is low. Therefore, how to prepare a catalyst with low cost, high activity, high selectivity, acid sites, high deoxygenation activity and high stability is a problem to be solved at present. SUMMARY

[0005] The main purpose of the present application is to provide a hydrodeoxygenation catalyst and its preparation method and application, aiming at solving the problems of high cost and low activity of existing catalysts, lack of acid sites leading to unsatisfactory deoxygenation activity in the reaction process, and poor stability of the catalyst.

[0006] To achieve the above-mentioned purpose, the present application provides a hydrodeoxygenation catalyst, which comprises a carrier and an active component, wherein Nb2O5 modified γ-Al2O3 is used as the carrier, and metal Fe and Ni are used as the active component.

[0007] The present application also provides a preparation method of the hydrodeoxygenation catalyst as described above, comprising the following steps:

[0008] S1, dissolving niobium oxalate in water, adding γ-Al2O3, stirring, drying, calcining to obtain Nb2O5 modified γ-Al2O3 carrier;

[0009] S2, dissolving nickel nitrate hexahydrate and iron nitrate nonahydrate in water, then mixing with the Nb2O5 modified γ-Al2O3 carrier to obtain a mixed solution, ultrasonic treating the mixed solution, impregnating, drying to obtain a solid;

[0010] S3, grinding the solid, calcining to obtain the hydrodeoxygenation catalyst.

[0011] Optionally, in step S1, the mass ratio of the niobium oxalate to γ-Al2O3 is 5-20:1-2.

[0012] Optionally, in step S1, the stirring time is 10-14h.

[0013] Optionally, in step S1, the drying temperature is 110-130℃; and / or,

[0014] The drying time is 10-14h.

[0015] Optionally, in step S1, the calcining temperature is 320-370℃; and / or,

[0016] The calcining time is 1-3h.

[0017] Optionally, in step S2, the mass ratio of the nickel nitrate hexahydrate, the iron nitrate nonahydrate, and the Nb2O5 modified and modified gamma-Al2O3 carrier is 2-6:4-16:15-90.

[0018] Optionally, in step S2, the ultrasonic treatment time is 8-12 min; and / or,

[0019] the impregnation time is 10-14 h; and / or,

[0020] the drying temperature is 90-110 DEG C; and / or,

[0021] the drying time is 10-14 h.

[0022] The application further provides an application of the hydrodeoxygenation catalyst or the hydrodeoxygenation catalyst prepared by the preparation method.

[0023] The isopropyl alcohol, guaiacol, and the hydrodeoxygenation catalyst are added into a high-pressure reaction container, and a magnetic stirrer is used, air in the high-pressure reaction container is replaced by hydrogen, vacuum is drawn, heating is performed, hydrogen is introduced until the reaction pressure reaches 2-6 MPa, and the hydrodeoxygenation reaction is performed to prepare cyclohexanol.

[0024] Optionally, the mass ratio of the isopropyl alcohol, guaiacol, and the hydrodeoxygenation catalyst is 50-150:3-8:1-3; and / or,

[0025] the hydrodeoxygenation reaction temperature is 150-250 DEG C; and / or,

[0026] the hydrodeoxygenation reaction time is 4-6 h.

[0027] The application has the following beneficial effects:

[0028] (1) In the technical scheme provided by the application, the Nb2O5 modification promotes the interaction between the Ni-Fe active component and the carrier surface, thereby preventing the loss of the active component during the reaction and improving the stability of the catalyst; and after the Nb2O5 modification, the electronic interaction between the Ni-Fe active component and the carrier is promoted, thereby improving the catalytic performance of the catalyst.

[0029] (2) This invention innovatively proposes the use of a Nb2O5-modified γ-Al2O3 supported Ni-Fe catalyst for the hydrodeoxygenation of guaiacol to cyclohexanol. The catalyst support γ-Al2O3 has excellent pore structure properties and acid sites on its surface. The acid sites of the support promote the removal of oxygen-containing functional groups in the hydrodeoxygenation process of guaiacol. The Nb2O5-modified γ-Al2O3 composite support is a support that has both acidity and good stability. Due to the introduction of the second metal, the bimetallic catalyst can effectively regulate the morphology and electronic structure of the main metal, thereby improving the catalytic performance of the bimetallic catalyst. Fe is an oxygen-loving metal, and the introduction of Fe is beneficial to promoting the hydrodeoxygenation reaction. The Nb2O5-modified γ-Al2O3 supported Ni-Fe bimetallic catalyst has excellent catalytic performance in the hydrodeoxygenation of guaiacol to cyclohexanol.

[0030] (3) The present invention provides a low-cost, economical, universal, environmentally friendly and non-corrosive equipment that can improve the yield of cyclohexanol under relatively mild reaction conditions when applied to the guaiacol hydrogenation process.

[0031] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, or solution B, or a solution where both A and B are satisfied simultaneously. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0034] Example 1

[0035] Preparation method of a hydrodeoxygenation catalyst and application thereof in guaiacol hydrodeoxygenation reaction

[0036] (1) 5.0 g of niobium oxalate was dissolved in distilled water, 1.0 g of γ-Al2O3 was added, stirred for 10 h, dried at 110°C for 10 h, and the dried solid powder was calcined at 320°C in a muffle furnace for 1 h to obtain a Nb2O5 modified γ-Al2O3 carrier;

[0037] (2) 2.0 g of nickel nitrate hexahydrate and 4.0 g of iron nitrate nonahydrate were dissolved in 50 mL of distilled water, then mixed with 1.5 g of the Nb2O5 modified γ-Al2O3 carrier to obtain a mixed solution, the mixed solution was ultrasonically treated for 8 min, and then impregnated for 10 h, and then dried at 90°C in an oven for 10 h to obtain a solid;

[0038] (3) The solid was ground and then placed in a tube furnace for calcination and reduction, the first stage was calcination at a temperature increasing rate of 5°C / min in a muffle furnace, the second stage was calcination at 400°C in a muffle furnace for 4 h, the third stage was reduction at 400°C in a tube furnace under hydrogen for 2 h, and the fourth stage was cooling to room temperature under nitrogen protection to obtain a hydrodeoxygenation catalyst;

[0039] (4) 10 g of isopropyl alcohol, 0.5 g of guaiacol, and 0.1 g of the hydrodeoxygenation catalyst were added to a high-pressure reaction kettle, and a magnetic stirrer was placed in the kettle, the kettle was sealed, the air in the kettle was replaced with hydrogen for 4 times, and then vacuumized, the kettle was placed in the jacket of an electric heating kettle and heated to 200°C, the hydrogen bottle total valve and the inlet valve were opened to introduce hydrogen to a reaction pressure of 4 MPa, and a hydrodeoxygenation reaction was carried out to prepare cyclohexanol;

[0040] (5) After 6 hours, the reaction was completed, the electric heating kettle and the hydrogen bottle total valve were closed, and the reaction kettle was placed in a cold water bath to cool to room temperature to obtain a cooled reaction liquid, which was filtered and quantified to obtain a product, and the product was qualitatively and quantitatively analyzed by gas chromatography.

[0041] Under the conditions of 200°C and 4.0 MPa, the guaiacol conversion rate was 99.9%, and the cyclohexanol selectivity was 90.1% after 6 hours of reaction.

[0042] Example 2

[0043] Preparation method of a hydrodeoxygenation catalyst and application thereof in guaiacol hydrodeoxygenation reaction

[0044] (1) 20.0 g of niobium oxalate was dissolved in distilled water, 2.0 g of γ-Al2O3 was added, stirred for 14 h, dried at 130°C for 14 h, and the dried solid powder was calcined at 370°C in a muffle furnace for 3 h to obtain a Nb2O5 modified γ-Al2O3 carrier;

[0045] (2) Dissolve 0.6 g of nickel nitrate hexahydrate and 1.6 g of iron nitrate nonahydrate in 50 mL of distilled water, then mix with 9.0 g of Nb2O5 modified γ-Al2O3 carrier to obtain a mixed solution, ultrasonic treat the mixed solution for 12 min, impregnate for 14 h, and dry in a drying oven at 110 ℃ for 14 h to obtain a solid;

[0046] (3) Grind the solid, then put it into a tube furnace for calcination and reduction, the first stage is to calcine in a muffle furnace at a temperature rising rate of 4 ℃ / min, the second stage is to calcine in a muffle furnace at 300 ℃ for 3 h, the third stage is to reduce in a tube furnace at 300 ℃ for 1 h under hydrogen condition, and the fourth stage is to cool to room temperature under nitrogen protection to obtain a hydrodeoxygenation catalyst;

[0047] (4) Put 5.0 g of isopropyl alcohol, 0.3 g of guaiacol, and 0.15 g of the hydrodeoxygenation catalyst into a high-pressure reaction kettle, and put the kettle into a magnetic stirrer, seal the kettle, replace the air in the kettle with hydrogen for 3 times, vacuumize, put the kettle into the jacket of an electric heating kettle, heat to 150 ℃, open the hydrogen bottle total valve and the inlet valve to introduce hydrogen to a reaction pressure of 3.0 MPa, and carry out hydrodeoxygenation reaction to prepare cyclohexanol;

[0048] (5) After 5 h, stop the electric heating kettle and the hydrogen bottle total valve, and put the reaction kettle into a cold water bath to cool to room temperature to obtain a cooled reaction liquid, filter and quantify to obtain a product, and use gas chromatography to qualitatively and quantitatively analyze the product.

[0049] Under the conditions of 150 ℃ and 3.0 MPa for 5 h, the conversion rate of guaiacol is 90.7%, and the selectivity of cyclohexanol is 87.5%.

[0050] Example 3

[0051] A preparation method of a hydrodeoxygenation catalyst and application thereof in a guaiacol hydrodeoxygenation reaction

[0052] (1) Dissolve 10.0 g of niobium oxalate in distilled water, add 1.5 g of γ-Al2O3, stir for 12 h, dry at 120 ℃ for 12 h, and calcine the dried solid powder in a muffle furnace at 350 ℃ for 2 h to obtain a Nb2O5 modified γ-Al2O3 carrier;

[0053] (2) Dissolve 0.4 g of nickel nitrate hexahydrate and 1.0 g of iron nitrate nonahydrate in 50 mL of distilled water, then mix with 5.0 g of the Nb2O5 modified γ-Al2O3 carrier to obtain a mixed solution, ultrasonic treat the mixed solution for 10 min, impregnate for 12 h, and dry in a drying oven at 100 ℃ for 12 h to obtain a solid;

[0054] (3) The solid is ground and then put into a tube furnace for roasting and reduction, the first stage is roasting in a muffle furnace at a temperature increasing rate of 6℃ / min, the second stage is roasting in the muffle furnace at 500℃ for 5h, the third stage is reduction in the tube furnace under hydrogen condition at 500℃ for 3h, and the fourth stage is cooling to room temperature 30℃ under nitrogen protection, to obtain a hydrogen-deoxidation catalyst;

[0055] (4) In a high-pressure reaction kettle, 15g of isopropyl alcohol, 0.8g of guaiacol and 0.3g of the hydrogen-deoxidation catalyst are added and put into a magnetic stirrer, the kettle is sealed, the air in the kettle is replaced with hydrogen for 5 times, vacuum is drawn, the kettle is put into the jacket of an electric heating kettle and heated to 250℃, the hydrogen bottle total valve and the inlet valve are opened to introduce hydrogen to a reaction pressure of 5MPa, and the hydrogen-deoxidation reaction is carried out to prepare cyclohexanol;

[0056] (5) After 7h, the reaction is completed, the electric heating kettle and the hydrogen bottle total valve are closed, the reaction kettle is put into a cold water bath to cool to room temperature, a cooled reaction liquid is obtained, filtration and quantification are carried out to obtain a product, and the product is qualitatively and quantitatively analyzed by gas chromatography.

[0057] Under the conditions of 250℃ and 5.0MPa for 7h, the conversion rate of guaiacol is 95.7% and the selectivity of cyclohexanol is 88.7%.

[0058] Comparative Example 1

[0059] A preparation method of a catalyst and application thereof in a guaiacol hydrogen-deoxidation reaction

[0060] (1) 1.0g of γ-Al2O3 is stirred in distilled water for 10h and dried at 110℃ for 10h, and then the dried solid powder is roasted in a muffle furnace at 320℃ for 1h to obtain a γ-Al2O3 carrier;

[0061] (2) 50mL of distilled water is added to 2.0g of nickel nitrate hexahydrate and 4.0g of iron nitrate nonahydrate to dissolve, and then mixed with 1.5g of the γ-Al2O3 carrier to obtain a mixed solution, the mixed solution is ultrasonically treated for 8min and impregnated for 10h, and then dried in a drying oven at 90℃ for 10h to obtain a solid;

[0062] (3) The solid is ground and then put into a tube furnace for roasting and reduction, the first stage is roasting in a muffle furnace at a temperature increasing rate of 6℃ / min, the second stage is roasting in the muffle furnace at 500℃ for 5h, the third stage is reduction in the tube furnace under hydrogen condition at 500℃ for 3h, and the fourth stage is cooling to room temperature 30℃ under nitrogen protection, to obtain a hydrogen-deoxidation catalyst;

[0063] (4) In the high-pressure reactor, 10 g of isopropyl alcohol, 0.5 g of guaiacol and 0.1 g of the catalyst were added and placed in a magnetic stirrer. After the reactor was sealed, the air in the reactor was replaced with hydrogen for 4 times, and then vacuumized. The reactor was placed in the jacket of an electric heating reactor and heated to 200℃. The hydrogen bottle total valve and the inlet valve were opened to introduce hydrogen to a reaction pressure of 4 MPa. The guaiacol was hydrogenated to prepare cyclohexanol;

[0064] (5) After 6 hours, the reaction was completed. The electric heating reactor and the hydrogen bottle total valve were closed, and the reactor was placed in a cold water bath to reduce the temperature to room temperature to obtain a cooled reaction liquid. The reaction liquid was filtered and quantified to obtain the product. The product was qualitatively and quantitatively analyzed by gas chromatography.

[0065] Under the conditions of 200℃ and 4.0 MPa for 6 hours, the conversion rate of guaiacol was 60.3%, and the selectivity of cyclohexanol was 59.8%.

[0066] Comparative Example 2

[0067] A preparation method of a catalyst and its application in guaiacol hydrogenation and deoxidation reaction

[0068] (1) 5.0 g of niobium oxalate was dissolved in distilled water, 1.0 g of γ-Al2O3 was added, stirred for 10 h, and dried at 110℃ for 10 h. The dried solid powder was calcined at 320℃ in a muffle furnace for 1 h to obtain a Nb2O5 modified γ-Al2O3 carrier;

[0069] (2) 2.0 g of nickel nitrate hexahydrate was dissolved in 50 mL of distilled water, and then mixed with 1.5 g of the Nb2O5 modified γ-Al2O3 carrier to obtain a mixed solution. The mixed solution was ultrasonically treated for 8 min and impregnated for 10 h. The solid was obtained by drying at 90℃ in an oven for 10 h;

[0070] (3) The solid was ground and then placed in a tube furnace for calcination and reduction. The first stage was calcination in a muffle furnace at a temperature increasing rate of 5℃ / min. The second stage was calcination at 400℃ in a muffle furnace for 4 h. The third stage was reduction at 400℃ in a tube furnace under hydrogen for 2 h. The fourth stage was cooling to room temperature under nitrogen protection to obtain a hydrogenation and deoxidation catalyst;

[0071] (4) In the high-pressure reactor, 10 g of isopropyl alcohol, 0.5 g of guaiacol and 0.1 g of the hydrogenation and deoxidation catalyst were added and placed in a magnetic stirrer. After the reactor was sealed, the air in the reactor was replaced with hydrogen for 4 times, and then vacuumized. The reactor was placed in the jacket of an electric heating reactor and heated to 200℃. The hydrogen bottle total valve and the inlet valve were opened to introduce hydrogen to a reaction pressure of 4 MPa. The guaiacol was hydrogenated to prepare cyclohexanol;

[0072] (5) After 6 hours, the reaction was completed, the electric heating kettle and the hydrogen bottle total valve were closed, the reaction kettle was placed in a cold water bath to reduce to room temperature, a cooled reaction liquid was obtained, filtered and quantified to obtain a product, and the product was qualitatively and quantitatively analyzed by gas chromatography.

[0073] The guaiacol conversion rate was 79.7% and the cyclohexanol selectivity was 73.8% under the condition of 200 DEG C and 4.0 MPa for 6 hours.

[0074] Compared with the gamma-Al2O3 carrier without modification in Comparative Example 1, the catalyst prepared in Examples 1-3 has a significantly improved guaiacol conversion rate and a greatly improved cyclohexanol selectivity in the preparation of cyclohexanol by guaiacol hydrodeoxygenation; compared with the catalyst without loading iron metal in Comparative Example 2, the catalyst prepared in Examples 1-3 loaded with Ni-Fe bimetal has a higher guaiacol conversion rate and a better cyclohexanol selectivity in the preparation of cyclohexanol by guaiacol hydrodeoxygenation.

[0075] In summary, in the technical solution provided by the present application, the stability of the catalyst is improved by modifying the Nb2O5 and loading the Ni-Fe bimetal active component, thereby improving the catalytic performance of the catalyst in the preparation of cyclohexanol by guaiacol hydrodeoxygenation, and the guaiacol conversion rate and the cyclohexanol selectivity are both improved.

[0076] The above is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the patent protection scope of the present application.

Claims

1. Use of a hydrodeoxygenation catalyst, characterized in that, The application is applied to catalytic guaiacol hydrogenation deoxidization reaction, comprising the following steps: Isopropanol, guaiacol and the hydrogenation deoxidization catalyst are added into a high-pressure reaction container, and a magnetic stirrer is put in, air in the high-pressure reaction container is replaced by hydrogen, vacuum is pumped, heated, hydrogen is introduced until the reaction pressure reaches 2-6 MPa, and the hydrogenation deoxidization reaction is carried out to prepare cyclohexanol; The hydrogenation deoxidization catalyst comprises a carrier and an active component, wherein γ-Al2O3 modified by Nb2O5 is used as the carrier, and Fe and Ni are used as the active component; The preparation method of the hydrogenation deoxidization catalyst comprises the following steps: S1, dissolving niobium oxalate in water, adding γ-Al2O3, stirring, drying, and calcining to obtain γ-Al2O3 modified by Nb2O5 as a carrier; S2, dissolving nickel nitrate hexahydrate and iron nitrate nonahydrate in water, then mixing with the γ-Al2O3 modified by Nb2O5 to obtain a mixed solution, ultrasonic treatment, impregnation, and drying to obtain a solid; S3, grinding and calcining the solid to obtain the hydrogenation deoxidization catalyst; In step S1, the mass ratio of the niobium oxalate to the γ-Al2O3 is 5-20:1-2; In step S2, the mass ratio of the nickel nitrate hexahydrate, the iron nitrate nonahydrate and the γ-Al2O3 modified by Nb2O5 is 2-6:4-16:15-90.

2. The use of a hydrodeoxygenation catalyst according to claim 1, characterized in that In step S1, the stirring time is 10-14 h.

3. The use of a hydrodeoxygenation catalyst according to claim 1, wherein In step S1, the drying temperature is 110-130°C; and / or, The drying time is 10-14 h.

4. The use of a hydrodeoxygenation catalyst according to claim 1, wherein In step S1, the calcination temperature is 320-370°C; and / or, The calcination time is 1-3 h.

5. The use of a hydrodeoxygenation catalyst according to claim 1, wherein In step S2, the ultrasonic treatment time is 8-12 min; and / or, The impregnation time is 10-14 h; and / or, The drying temperature is 90-110°C; and / or, The drying time is 10-14 h.

6. The use according to claim 1, wherein The mass ratio of the isopropanol, the guaiacol and the hydrogenation deoxidization catalyst is 50-150:3-8:1-3; and / or, The hydrogenation deoxidization reaction temperature is 150-250°C; and / or, The hydrogenation deoxidization reaction time is 4-6 h.