A NiCoAl / C catalyst and its application in furfural conversion

Abstract

The invention proposes a NiCoAl / C catalyst and application thereof in furfural conversion, belonging to the technical field of biomass conversion. The invention uses furfural as a raw material and NiCoAl / C as a catalyst, and catalyzes furfural to prepare cyclopentanone or tetrahydrofurfuryl alcohol with high selectivity and high conversion rate through simple regulation of the catalyst. Non-precious metal raw materials are used, the raw materials are easy and cheap to obtain, the process is simple, and the invention has good application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass conversion, and in particular relates to a NiCoAl / C catalyst and application thereof in furfural conversion. Background Art

[0002] The depletion of fossil fuels and petrochemicals has brought challenges of energy crisis and environmental pollution to mankind. For these reasons, biomass and its derivatives have attracted increasing attention in the production of renewable biofuels and value-added compounds, especially the conversion towards second-generation biofuels and platform molecules. Furfural is usually obtained by dehydration of xylose, a hemicellulose-derived pentose found in agricultural wastes such as corn stover, corn cobs and peanut shells. Furfural as a feedstock can be catalytically converted into a series of high value-added chemicals such as furfuryl alcohol (FOL), tetrahydrofurfuryl alcohol (THFOL), pentanediol (PeD), 2-methylfuran (MeF), 2-methyltetrahydrofuran (MTHF), cyclopentanone (CPO), etc. The hydrogenation products are highly dependent on the catalyst and reaction conditions.

[0003] Cyclopentanone is an important chemical intermediate in the production of pharmaceuticals, pesticides and rubber chemicals. In current industrial practice, cyclopentanone is produced by pyrolysis of adipic acid and its derivatives or oxidation of cyclopentene, which uses fossil products as raw materials, is energy-intensive, environmentally harmful and cost-ineffective.

[0004] Tetrahydrofurfuryl alcohol is a fully hydrogenated product and is widely used as a green solvent in the fields of medicine, industry and agriculture. In industry, the production of tetrahydrofurfuryl alcohol from furfural includes two consecutive steps: one is to hydrogenate furfural to produce furfuryl alcohol, and the other is to further hydrogenate furfuryl alcohol to produce tetrahydrofurfuryl alcohol. It is very ideal to synthesize tetrahydrofurfuryl alcohol from furfural in one step.

[0005] In contrast, the production of cyclopentanone and tetrahydrofurfuryl alcohol from furfural is a feasible and sustainable method. If biomass resources can be converted into high-value chemicals such as cyclopentanone and tetrahydrofurfuryl alcohol, on the one hand, the high-value utilization of biomass resources can be achieved, and on the other hand, the increasingly scarce energy situation can be alleviated, and carbon emissions can also be reduced. The present invention provides a high-efficiency NiCoAl / C catalyst, which can obtain high-yield cyclopentanone or tetrahydrofurfuryl alcohol through simple regulation of the catalyst, which is in line with the current concept of sustainable development. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a NiCoAl / C catalyst and its application in furfural conversion. The present invention uses furfural as a raw material and NiCoAl / C as a catalyst, and through simple regulation of the catalyst, furfural is catalyzed to prepare cyclopentanone or tetrahydrofurfuryl alcohol with high selectivity.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention:

[0009] The invention provides a NiCoAl / C catalyst, wherein the molar ratio of Ni, Co and Al in the NiCoAl / C catalyst is (0-1):(0-1):(0-4); and the molar ratio of Ni, Co and Al in the NiCoAl / C catalyst is not 0 at the same time.

[0010] Furthermore, the molar ratio of Ni, Co and Al in the NiCoAl / C catalyst is (0.5-1):(0.5-1):(0.5-2).

[0011] Furthermore, the molar ratio of Ni, Co and Al in the NiCoAl / C catalyst is 1:1:1.

[0012] The second technical solution of the present invention:

[0013] The present invention provides a method for preparing the NiCoAl / C catalyst, comprising the following steps:

[0014] Dissolve sodium hydroxide (NaOH) in water, add guaiacol, and stir evenly to obtain a mixed solution;

[0015] Add nickel salt, cobalt salt and aluminum salt to the mixed solution, stir evenly, filter the precipitate, wash or not wash, dry, calcine, and reduce under hydrogen atmosphere to obtain NiCoAl / C catalyst.

[0016] Furthermore, the nickel salt, cobalt salt and aluminum salt are respectively Ni(NO 3 ) 2 、Co(NO 3 ) 2 and Al(CH 3 COO 3 .

[0017] Furthermore, the molar ratio of sodium hydroxide to guaiacol is 1:1.

[0018] Furthermore, the molar ratio of sodium hydroxide to nickel salt is (1.5-2.5):1, preferably 2:1.

[0019] Furthermore, the calcination temperature is 500-700°C;

[0020] The reduction temperature is 400-500°C.

[0021] Furthermore, the preparation method of the NiCoAl / C catalyst comprises the following steps:

[0022] Step 1, dissolving NaOH in ultrapure water, adding guaiacol thereto, stirring the mixture evenly, and finally turning it into a dark brown mixed solution;

[0023] Step 2: Ni(NO 3 ) 2 、Co(NO 3 ) 2 and Al(CH 3 COO 3 Add into the above mixed solution and then stir;

[0024] Step 3, filtering the precipitate in the above solution, washing it with ultrapure water several times, and then drying it in an oven to completely remove moisture;

[0025] Step 4: Grind the dried precipitate solid with a mortar, sieve it, and place it in a tube furnace. 2 calcined at 500℃-700℃ in H 2 The catalyst obtained by reduction at 400°C-500°C under the atmosphere is recorded as NiCoAl / C(W) catalyst;

[0026] Alternatively, in step 3, the precipitate is filtered but not washed, and the other steps are the same, and the catalyst finally obtained is recorded as NiCoAl / C (UW) catalyst.

[0027] Furthermore, in step 1, the molar ratio of NaOH to guaiacol is 1:1, the stirring time is 30 min, and the stirring speed is 600 r / min; in step 2, NaOH and Ni(NO 3 ) 2 The molar ratio is 2:1; in step 3, the drying time in the oven is 24h, and the drying temperature is 80°C; the mesh size of the sieve in step 4 is 80-100 mesh; the heating rate of the tubular furnace is 10°C / min, N 2 The calcination temperature is preferably 600° C. and the calcination time is 1 h. The hydrogen reduction temperature is preferably 450° C. and the reduction time is 4 h.

[0028] The present invention simply modifies the catalyst by adjusting the pH value during the catalyst preparation process (i.e., by washing to neutrality or without washing), thereby changing the phase composition of the catalyst. Cobalt aluminate exists in the NiCoAl / C(UW) catalyst, while the substance is not detected in the NiCoAl / C(W) catalyst. The NiCoAl / C(UW) catalyst contains a large amount of reduced metals, which is conducive to the generation of tetrahydrofurfuryl alcohol, while the NiCoAl / C(W) catalyst contains abundant acid sites, which is conducive to the conversion into cyclopentanone. The adsorption configurations of furfural on the two catalysts are also different. Furfural on the NiCoAl / C(UW) catalyst is a parallel adsorption configuration, which is conducive to the hydrogenation of double bonds; while furfural on the NiCoAl / C(W) catalyst is a vertical adsorption configuration, which is conducive to the ring opening.

[0029] The third technical solution of the present invention:

[0030] The present invention provides application of the NiCoAl / C catalyst in furfural conversion.

[0031] Furthermore, the NiCoAl / C catalyst is used to catalyze furfural to prepare cyclopentanone or tetrahydrofurfuryl alcohol.

[0032] Furthermore, the present invention uses furfural as a raw material and water as a solvent, and catalytically converts cyclopentanone or tetrahydrofurfuryl alcohol with high selectivity under the action of a NiCoAl / C catalyst, the reaction temperature is 120-180°C, preferably 150-170°C, the reaction time is 2-16h, preferably 4-12h, and the hydrogen pressure in the reaction system is 1-6MPa, preferably 2-5MPa.

[0033] The mass of furfural is 0.1-2wt% of water, preferably 0.64wt%, and the mass of NiCoAl / C catalyst is 10-50wt% of furfural, preferably 30-35wt%, and most preferably 31.2wt%.

[0034] Compared with the prior art, the present invention has the following advantages and technical effects:

[0035] 1. The present invention provides a NiCoAl / C catalyst and its application in furfural conversion. The NiCoAl / C catalyst of the present invention achieves the purpose of catalytic conversion of furfural to cyclopentanone or tetrahydrofurfuryl alcohol with high conversion rate and high selectivity through the synergistic effect of three metals.

[0036] 2. The present invention adjusts the yield of cyclopentanone or tetrahydrofurfuryl alcohol by simply regulating the catalyst, adjusting the pH value by washing the catalyst, and changing the properties of the catalyst.

[0037] 3. The catalyst of the present invention uses non-precious metal raw materials, the raw materials are easy and cheap to obtain, the process is simple, and it has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0039] Figure 1 is the GC-MS spectrum of the catalytic conversion of furfural into cyclopentanone and tetrahydrofurfuryl alcohol in Example 6;

[0040] Figure 2 is the XRD pattern of the catalyst of Example 1-17;

[0041] Figure 3 is the NH of the catalysts of Examples 1, 4, 5, 8-17 3 -TPD graph;

[0042] Figure 4 is the pyridine infrared image of the catalyst of Example 4;

[0043] Figure 5 It is the pyridine infrared image of the catalyst of Example 8-17. DETAILED DESCRIPTION

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0045] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0046] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0047] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0048] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0049] All raw materials used in the examples of the present invention are commercially available.

[0050] The technical solution of the present invention is further illustrated by the following embodiments.

[0051] Example 1

[0052] Catalyst preparation:

[0053] (1) Dissolve 0.02 mol of NaOH in 50 mL of ultrapure water, add 0.02 mol of guaiacol, stir the mixture at 400 r / min for 30 min, and finally turn into a dark brown mixed solution.

[0054] (2) Ni(NO 3 ) 2 、Co(NO 3 ) 2 (both 0.005 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0055] (3) The precipitate in the above solution was filtered and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0056] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The reduction was carried out at 450℃ for 4h under the atmosphere, and the heating rate of the tube furnace was 10℃ / min. The catalyst finally obtained was recorded as NiCo / C(UW) catalyst.

[0057] Reaction evaluation: The NiCo / C(UW) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen 5 times, and then 2MPa of hydrogen was filled, and the reaction was carried out at 160°C for 8h, with a heating rate of 5°C / min, and the reaction was cooled to room temperature after the reaction was completed. The liquid and gas components were analyzed by gas chromatography and GC-MS, and the furfural conversion rate was 100%, and the tetrahydrofurfuryl alcohol yield was 58.58%. The reaction evaluation conditions and results are shown in Table 1.

[0058] Example 2

[0059] Catalyst preparation:

[0060] (1) 0.025 mol of NaOH was dissolved in 50 mL of ultrapure water, and 0.025 mol of guaiacol was added thereto. The mixture was stirred at 400 r / min for 30 min, and finally turned into a dark brown mixed solution.

[0061] (2) Ni(NO 3 ) 2 、Al(CH 3 COO 3 (both 0.005 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0062] (3) The precipitate in the above solution was filtered and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0063] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The reduction was carried out at 450℃ for 4h under the atmosphere, and the heating rate of the tube furnace was 10℃ / min. The catalyst finally obtained was recorded as NiAl / C(UW) catalyst.

[0064] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 1.

[0065] Example 3

[0066] Catalyst preparation:

[0067] (1) 0.025 mol of NaOH was dissolved in 50 mL of ultrapure water, and 0.025 mol of guaiacol was added thereto. The mixture was stirred at 400 r / min for 30 min, and finally turned into a dark brown mixed solution.

[0068] (2) Co(NO 3 ) 2 、Al(CH 3 COO 3 (both 0.005 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0069] (3) The precipitate in the above solution was filtered and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0070] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The reduction was carried out at 450°C for 4 h under the atmosphere, and the heating rate of the tube furnace was 10°C / min. The catalyst finally obtained was recorded as CoAl / C(UW) catalyst.

[0071] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 1.

[0072] Example 4

[0073] Catalyst preparation:

[0074] (1) 0.035 mol of NaOH was dissolved in 50 mL of ultrapure water, and 0.035 mol of guaiacol was added thereto. The mixture was stirred at 400 r / min for 30 min, and finally turned into a dark brown mixed solution.

[0075] (2) Ni(NO 3 ) 2 、Co(NO 3 ) 2 、Al(CH 3 COO 3 (both 0.005 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0076] (3) The precipitate in the above solution was filtered and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0077] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The reduction was carried out at 450℃ for 4h under the atmosphere, and the heating rate of the tube furnace was 10℃ / min. The catalyst finally obtained was recorded as NiCoAl / C(UW) catalyst.

[0078] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 1.

[0079] Example 5

[0080] Catalyst preparation:

[0081] (1) Dissolve 0.02 mol of NaOH in 50 mL of ultrapure water, add 0.02 mol of guaiacol, stir the mixture at 400 r / min for 30 min, and finally turn into a dark brown mixed solution.

[0082] (2) Ni(NO 3 ) 2 、Co(NO 3 ) 2 (both 0.005 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0083] (3) The precipitate in the above solution was filtered, washed with water until the pH was about 7, and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0084] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The reduction was carried out at 450°C for 4 h under the atmosphere, and the heating rate of the tube furnace was 10°C / min. The catalyst finally obtained was recorded as NiCo / C(W) catalyst.

[0085] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 2.

[0086] Example 6

[0087] Catalyst preparation:

[0088] (1) 0.025 mol of NaOH was dissolved in 50 mL of ultrapure water, and 0.025 mol of guaiacol was added thereto. The mixture was stirred at 400 r / min for 30 min, and finally turned into a dark brown mixed solution.

[0089] (2) Ni(NO 3 ) 2 、Al(CH 3 COO 3 (both 0.005 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0090] (3) The precipitate in the above solution was filtered, washed with water until the pH was about 7, and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0091] (4) The dried solid was ground in a mortar and calcined at 600 °C for 1 h in a tube furnace under N2 atmosphere and then heated in H 2 The reduction was carried out at 450℃ for 4h under the atmosphere, and the heating rate of the tube furnace was 10℃ / min. The catalyst finally obtained was recorded as NiAl / C(W) catalyst.

[0092] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 2.

[0093] Example 7

[0094] Catalyst preparation:

[0095] (1) 0.025 mol of NaOH was dissolved in 50 mL of ultrapure water, and 0.025 mol of guaiacol was added thereto. The mixture was stirred at 400 r / min for 30 min, and finally turned into a dark brown mixed solution.

[0096] (2) Co(NO 3 ) 2 、Al(CH 3 COO 3 (both 0.005 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0097] (3) The precipitate in the above solution was filtered, washed with water until the pH was about 7, and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0098] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The reduction was carried out at 450°C for 4 h under the atmosphere, and the heating rate of the tube furnace was 10°C / min. The catalyst finally obtained was recorded as CoAl / C(W) catalyst.

[0099] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 2.

[0100] Example 8

[0101] Catalyst preparation:

[0102] (1) 0.035 mol of NaOH was dissolved in 50 mL of ultrapure water, and 0.035 mol of guaiacol was added thereto. The mixture was stirred at 400 r / min for 30 min, and finally turned into a dark brown mixed solution.

[0103] (2) Ni(NO 3 ) 2 、Co(NO 3 ) 2 、Al(CH 3 COO 3 (both 0.005 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0104] (3) The precipitate in the above solution was filtered, washed with water until the pH was about 7, and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0105] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The reduction was carried out at 450°C for 4 h under the atmosphere, and the heating rate of the tube furnace was 10°C / min. The catalyst finally obtained was recorded as NiCoAl / C(W) catalyst.

[0106] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 2.

[0107] Example 9

[0108] Catalyst preparation: Same as Example 8.

[0109] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen for 5 times, and then 2MPa of hydrogen was filled in, and the reaction was carried out at 160°C for 8h, with a heating rate of 5°C / min, and after the reaction was completed, the reaction was cooled to room temperature, and the liquid and gas components were analyzed by gas chromatography and GC-MS. The furfural conversion rate was 95.45%, and the cyclopentanone yield was 87.48%. The reaction evaluation conditions and results are shown in Table 2.

[0110] Example 10

[0111] Catalyst preparation: Same as Example 8.

[0112] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen 5 times, and then 4MPa of hydrogen was filled, and the reaction was carried out at 160°C for 8h, with a heating rate of 5°C / min, and the reaction was cooled to room temperature after the reaction was completed. The liquid and gas components were analyzed by gas chromatography and GC-MS, and the furfural conversion rate was 100%, and the cyclopentanone yield was 95.37%. The reaction evaluation conditions and results are shown in Table 2.

[0113] Embodiment 11

[0114] Catalyst preparation: Same as Example 8.

[0115] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen for 5 times, and then 5MPa of hydrogen was filled, and the reaction was carried out at 160°C for 8h, with a heating rate of 5°C / min, and after the reaction was completed, the reaction was cooled to room temperature, and the liquid and gas components were analyzed by gas chromatography and GC-MS. The furfural conversion rate was 100%, and the cyclopentanone yield was 92.21%. The reaction evaluation conditions and results are shown in Table 2.

[0116] Example 12

[0117] Catalyst preparation: Same as Example 8.

[0118] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen 5 times, and then 3MPa of hydrogen was filled, and the reaction was carried out at 150°C for 8h, with a heating rate of 5°C / min, and the reaction was cooled to room temperature after the reaction was completed. The liquid and gas components were analyzed by gas chromatography and GC-MS, and the furfural conversion rate was 93.87%, and the cyclopentanone yield was 88.87%. The reaction evaluation conditions and results are shown in Table 2.

[0119] Example 13

[0120] Catalyst preparation: Same as Example 8.

[0121] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen 5 times, and then 3MPa of hydrogen was filled, and the reaction was carried out at 170°C for 8h, with a heating rate of 5°C / min, and the reaction was cooled to room temperature after the reaction was completed. The liquid and gas components were analyzed by gas chromatography and GC-MS, and the furfural conversion rate was 100%, and the cyclopentanone yield was 89.36%. The reaction evaluation conditions and results are shown in Table 2.

[0122] Embodiment 14

[0123] Catalyst preparation: Same as Example 8.

[0124] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen 5 times, and then 3MPa of hydrogen was filled, and the reaction was carried out at 160°C for 4h, with a heating rate of 5°C / min, and the reaction was cooled to room temperature after the reaction was completed. The liquid phase components and gas phase components were analyzed by gas chromatography and GC-MS, and the furfural conversion rate was 92.76%, and the cyclopentanone yield was 84.10%. The reaction evaluation conditions and results are shown in Table 2.

[0125] Embodiment 15

[0126] Catalyst preparation: Same as Example 8.

[0127] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen for 5 times, and then 3MPa of hydrogen was filled in, and the reaction was carried out at 160°C for 6h, with a heating rate of 5°C / min, and the reaction was cooled to room temperature after the reaction was completed. The liquid and gas components were analyzed by gas chromatography and GC-MS, and the furfural conversion rate was 98.33%, and the cyclopentanone yield was 90.34%. The reaction evaluation conditions and results are shown in Table 2.

[0128] Example 16

[0129] Catalyst preparation: Same as Example 8.

[0130] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen for 5 times, and then 3MPa of hydrogen was filled in, and the reaction was carried out at 160°C for 10h, with a heating rate of 5°C / min, and after the reaction was completed, the reaction was cooled to room temperature, and the liquid and gas components were analyzed by gas chromatography and GC-MS. The furfural conversion rate was 100%, and the cyclopentanone yield was 96.08%. The reaction evaluation conditions and results are shown in Table 2.

[0131] Embodiment 17

[0132] Catalyst preparation: Same as Example 8.

[0133] Reaction evaluation: The NiCoAl / C(W) catalyst prepared by the above method was added to a high-pressure reactor, and furfural and water were added, mixed evenly, and the reactor was sealed; wherein the mass of furfural was 0.64wt% of the mass of water; the mass of the catalyst was 31.2wt% of the mass of furfural; then the air in the autoclave was replaced with hydrogen for 5 times, and then 3MPa of hydrogen was filled in, and the reaction was carried out at 160°C for 12h, with a heating rate of 5°C / min, and after the reaction was completed, the reaction was cooled to room temperature, and the liquid and gas components were analyzed by gas chromatography and GC-MS. The furfural conversion rate was 100%, and the cyclopentanone yield was 91.77%. The reaction evaluation conditions and results are shown in Table 2.

[0134] Embodiment 18

[0135] Catalyst preparation:

[0136] (1) Dissolve 0.05 mol of NaOH in 50 mL of ultrapure water, add 0.05 mol of guaiacol, stir the mixture at 400 r / min for 30 min, and finally turn into a dark brown mixed solution.

[0137] (2) Ni(NO 3 ) 2 、Co(NO 3 ) 2 (0.005 mol, 10 mL aqueous solution), Al(CH 3 COO 3 (0.01 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0138] (3) The precipitate in the above solution was filtered, washed with water until the pH was about 7, and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0139] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The catalyst was reduced at 450 °C for 4 h under a vacuum atmosphere, and the heating rate of the tube furnace was 10 °C / min. 2 / C(W) catalyst.

[0140] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 2.

[0141] Embodiment 19

[0142] Catalyst preparation:

[0143] (1) Dissolve 0.08 mol of NaOH in 50 mL of ultrapure water, add 0.08 mol of guaiacol, stir the mixture at 400 r / min for 30 min, and finally turn into a dark brown mixed solution.

[0144] (2) Ni(NO 3 ) 2 、Co(NO 3 ) 2 (0.005 mol, 10 mL aqueous solution), Al(CH 3 COO 3 (0.02 mol, 10 mL aqueous solution) was added to the above dark brown mixed solution, and then stirred at 400 r / min for 30 min.

[0145] (3) The precipitate in the above solution was filtered, washed with water until the pH was about 7, and then dried in an oven at 80°C for 24 h to completely remove moisture.

[0146] (4) The dried solid was ground in a mortar and then heated in a tube furnace. 2 calcined at 600 °C for 1 h in H 2 The catalyst was reduced at 450 °C for 4 h under a vacuum atmosphere, and the heating rate of the tube furnace was 10 °C / min. 4 / C(W) catalyst.

[0147] Reaction evaluation: The operating procedure of the reaction evaluation is consistent with that of Example 1, but the reaction conditions and results are shown in Table 2.

[0148] Table 1

[0149]

[0150] Table 2

[0151]

[0152]

[0153] The GC-MS spectrum of furfural catalytic conversion into cyclopentanone and tetrahydrofurfuryl alcohol in Example 6 is shown in Figure 1 ;

[0154] The XRD patterns of the catalysts of Examples 1-17 are shown in Figure 2 ;

[0155] NH of the catalysts of Examples 1, 4, 5, 8-17 3 -TPD chart Figure 3 ;

[0156] The pyridine infrared image of the catalyst of Example 4 is shown in Figure 4 ;

[0157] The pyridine infrared image of the catalyst of Example 8-17 is shown in Figure 5 .

[0158] By comparing Example 4 with Example 8, it can be seen that the NiCoAl / C catalyst catalyzes furfural to produce tetrahydrofurfuryl alcohol and cyclopentanone with high conversion rate and high selectivity before and after the washing treatment. Specifically, the phase composition of the catalyst is changed before and after the washing treatment of the NiCoAl / C catalyst, thereby changing the adsorption configuration of furfural on the catalyst, so that furfural is converted into tetrahydrofurfuryl alcohol and cyclopentanone with high conversion rate and high selectivity.

[0159] By comparing Example 4 with Example 8, it can be seen that the properties of the NiCoAl / C catalyst can be easily controlled by adjusting the pH during the preparation process, thereby changing the yield of the main product.

[0160] Comparison of Examples 1, 2, 3, and 4 shows that the synergistic effect of Ni, Co, and Al promotes the highly selective conversion of furfural into cyclopentanone.

[0161] Comparison of Examples 5, 6, 7, and 8 shows that Co and Al act synergistically, while Ni plays an auxiliary hydrogenation role to promote the high-selective conversion of furfural into cyclopentanone.

[0162] By comparing Example 8 with Examples 18 and 19, it can be seen that increasing the proportion of Al in the catalyst reduces the hydrogenation effect of the catalyst, and more substrate is converted into the intermediate product furfuryl alcohol, thereby reducing the yield of cyclopentanone, proving that the catalyst molar ratio in Example 8 is the most preferred.

[0163] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing a NiCoAl / C catalyst, characterized in that: The following steps are involved: Dissolve sodium hydroxide in water, add guaiacol, and stir evenly to obtain a mixed solution; Adding nickel salt, cobalt salt and aluminum salt to the mixed solution, stirring evenly, filtering the precipitate, drying without washing, calcining, and reducing under hydrogen atmosphere to obtain NiCoAl / C catalyst, which is recorded as NiCoAl / C (UW) catalyst; The nickel salt, cobalt salt and aluminum salt are Ni(NO3)2, Co(NO3)2 and Al(CH3COO)3 respectively; The molar ratio of sodium hydroxide to guaiacol is 1:1; The molar ratio of the sodium hydroxide to the nickel salt is (1.5-2.5):1; The calcination temperature is 500-700°C; The reduction temperature is 400-500°C; The molar ratio of Ni, Co and Al in the NiCoAl / C catalyst is (0-1):(0-1):(0-4); the molar numbers of Ni, Co and Al in the NiCoAl / C catalyst are not 0; The NiCoAl / C catalyst is used for catalyzing furfural to prepare tetrahydrofurfuryl alcohol.

2. The method for preparing the NiCoAl / C catalyst according to claim 1, characterized in that: The molar ratio of Ni, Co and Al in the NiCoAl / C catalyst is (0.5-1):(0.5-1):(0.5-2).

3. The method for preparing the NiCoAl / C catalyst according to claim 2, characterized in that: The molar ratio of Ni, Co and Al in the NiCoAl / C catalyst is 1:1:

1.

4. Use of a NiCoAl / C catalyst prepared according to the method according to any one of claims 1 to 3 in catalyzing furfural to prepare tetrahydrofurfuryl alcohol.

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