Supported catalysts for the gas phase hydrodeoxygenation of furfural and methods of making and using the same

Abstract

The application relates to the technical field of catalytic hydrogenation, in particular to a supported catalyst for furaldehyde gas-phase hydrogenation deoxygenation and a preparation and use method thereof. The supported catalyst has high activity, high selectivity of hydrogenation deoxygenation products and high catalytic stability. The supported catalyst is used for catalyzing furaldehyde gas-phase selective hydrogenation deoxygenation; the supported catalyst comprises a carrier and an active component supported on the carrier, and the active component comprises molybdenum oxide. The application is used for preparing 2-methyl furan by furaldehyde gas-phase hydrogenation deoxygenation.

Description

Technical Field

[0001] This application relates to the field of catalytic hydrogenation technology, and in particular to a supported catalyst for the gas-phase hydrogenation deoxygenation of furfural and its preparation and use methods. Background Technology

[0002] With the increasing depletion of fossil fuels globally, the development and utilization of biomass energy has become an effective way to achieve sustainable development for human society. Biomass energy, namely lignocellulose, is mainly composed of cellulose, hemicellulose, and lignin. In the past few decades, the conversion of cellulose and hemicellulose has developed rapidly, yielding many commercial products such as ethanol and furfural.

[0003] Furfural is an important raw material for the preparation of high-value-added chemicals. In the preparation of hydrodeoxygenation products such as 2-methylfuran, furfuryl alcohol, tetrahydrofurfural alcohol and methyltetrahydrofuran, the selectivity of each hydrodeoxygenation product is the key to the hydrodeoxygenation reaction of furfural, which seriously affects the conversion efficiency of furfural in the reaction process.

[0004] Currently, taking 2-methylfuran as an example of a product of hydrodeoxygenation, the main method for converting furfural is to use Cu-Cr composite oxide catalysts. However, 2-methylfuran has low selectivity, and Cr-containing catalysts cause environmental pollution, making them unsuitable for large-scale use. Meanwhile, Cu... + Supported catalysts prepared by adding alkali metals and / or alkaline earth metals as co-catalysts to the active component will, when used, exhibit problems due to the presence of Cu in the active component. + During the hydrodeoxygenation process, it is easily reduced to Cu metal, and Cu metal is prone to migration and aggregation on the catalyst surface, which makes the catalyst prone to sintering, crystal growth, reduced activity, poor stability, requiring multiple separation and regeneration, and causing great environmental pollution. Summary of the Invention

[0005] Therefore, it is necessary to provide a supported catalyst for the gas-phase hydrodeoxygenation of furfural, as well as its preparation and application method. This supported catalyst exhibits high activity, high selectivity for the hydrodeoxygenation products, and high catalytic stability.

[0006] In a first aspect, a supported catalyst is provided for catalyzing the gas-phase selective hydrodeoxygenation of furfural; the supported catalyst comprises: a support, and an active component supported on the support, the active component comprising molybdenum oxide.

[0007] Optionally, in the supported catalyst, the active component contains molybdenum at a mass percentage of 0.1 wt% to 40 wt%.

[0008] Optionally, the molecular formula of the molybdenum oxide is represented as MoO. x, of which 0 <x≤3。

[0009] Optionally, the support is selected from one or more of TiO2, SiO2, MCM-41, ZrO2, Al2O3, MgO and CeO2.

[0010] In a second aspect, a method for preparing a supported catalyst as described in the first aspect is provided, comprising:

[0011] The supported catalyst is prepared by loading the active component onto the support through impregnation or co-precipitation.

[0012] Optionally, the impregnation method for loading molybdenum oxide onto the support to prepare the supported catalyst includes:

[0013] Prepare a precursor solution of the active component;

[0014] While stirring, the precursor solution is dropped onto the carrier so that the precursor solution adheres to the carrier;

[0015] The supported catalyst is prepared by drying, calcining, and granulating the support to which the precursor solution is attached.

[0016] Optionally, the precursor solution of the active component satisfies at least one of the following conditions:

[0017] (1) The precursor of the active component includes at least one of molybdate, molybdic acid and molybdenum oxide;

[0018] Optionally, the precursor of the active component includes one or more of the following: ammonium heptamolybdate, ammonium molybdate, sodium molybdate, molybdenum pentachloride, sodium phosphomolybdate, 12-silicomolybdic acid, and molybdenum trioxide;

[0019] (2) The concentration of the precursor of the active component in the precursor solution is 0.001 g / mL to 0.4 g / mL.

[0020] Optionally, during impregnation, the preparation method further includes: ultrasonically treating the impregnated precursor solution and the carrier to cause the precursor solution to diffuse in the carrier.

[0021] Optionally, the ultrasonic treatment power is 50W to 250W, and the time is 0.5h to 4h.

[0022] Optionally, the drying temperature is 90℃~120℃, and the time is 8h~24h;

[0023] And / or,

[0024] The roasting temperature is 400℃~900℃, and the time is 3h~8h;

[0025] And / or,

[0026] The supported catalyst used in the tableting and granulation process has a mesh size of 10 to 100 mesh.

[0027] Optionally, the preparation method further includes activating the supported catalyst.

[0028] Optionally, the activation of the supported catalyst includes:

[0029] The supported catalyst is subjected to a pre-reduction treatment to activate it.

[0030] Optionally, the supported catalyst is pre-reduced using a reducing gas, the reducing gas including hydrogen or a mixture of hydrogen and an inert gas.

[0031] Optionally, in the reducing gas, the volume percentage of hydrogen is 20% to 100%;

[0032] Optionally, the pre-reduction treatment is carried out at a temperature of 200℃ to 600℃ for a time of 0.5h to 5h.

[0033] Thirdly, a method for gas-phase hydrogenation deoxygenation of furfural using a supported catalyst as described in the first aspect is provided, comprising:

[0034] Vaporization treatment of furfural or furfural solution;

[0035] The furfural or furfural solution after gasification is subjected to a hydrodeoxygenation reaction under the catalysis of the supported catalyst to prepare the hydrodeoxygenation product.

[0036] Optionally, the hydrogenation deoxygenation product is 2-methylfuran;

[0037] Hydrogen gas is brought into contact with the gasified furfural or furfural solution to cause a hydrogenation deoxygenation reaction in the gasified furfural or furfural solution, wherein the molar ratio of hydrogen gas to furfural is (30-500):1.

[0038] Optionally, the hydrodeoxygenation reaction is carried out at a temperature of 200℃ to 600℃, a pressure of 0.1 MPa to 1 MPa, and a total space velocity of 800 mL / h. -1 g cat -1 ~90000mL h -1 g cat -1 .

[0039] Optionally, the solvent used to prepare the furfural solution includes one or more of the following: cyclopentyl methyl ether, 1,4-dioxane, anisole, cyclopentane, toluene, methanol, ethanol, n-propanol, isopropanol, n-butanol, and isobutanol.

[0040] Optionally, in the furfural solution, the molar ratio of the solvent used to prepare the furfural solution to furfural is greater than 0 and less than or equal to 300.

[0041] Compared with the prior art, this application has the following beneficial effects:

[0042] By loading an active component, including molybdenum oxide, onto a support, the oxygen vacancies on the molybdenum oxide can capture oxygen from the carbonyl group of furfural during use. Furthermore, the selectivity of different hydrodeoxygenation products can be improved by adjusting the molybdenum content in the supported catalyst and the catalytic reaction conditions. Simultaneously, compared with related technologies that use Cu... + Compared to supported catalysts prepared by adding alkali metals and / or alkaline earth metals as co-catalysts to the active component, molybdenum oxide exhibits a more stable structure, is less prone to excessive reduction that could decrease the active component, and has a higher atomic number, making it less susceptible to migration. Furthermore, the catalyst is less prone to sintering and is more stable. Therefore, it can address the problems in related technologies, such as poor selectivity in the preparation of hydrodeoxygenation products from furfural, the tendency for catalysts to sinter and grow crystals, resulting in reduced activity, poor stability, the need for multiple separation and regeneration processes, and significant environmental pollution. Detailed Implementation

[0043] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0044] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "exemplary," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0045] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0046] In this document, unless otherwise stated, "one or more" means one or more.

[0047] In this document, terms such as "for example," "like," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the content covered by different technical solutions presented earlier and later. However, they should not be construed as limitations on the preceding technical solution or as restrictions on the scope of protection of this document. In this document, unless otherwise specified, A (like B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0048] In this article, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "options" in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "option" is independent.

[0049] In this article, descriptions such as "optionally contains" and "optionally includes" indicate whether or not the component X is present. "Optional component X" indicates whether component X is present or absent, or whether or not component X is present.

[0050] In this document, the terms "first aspect," "second aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0052] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0053] In this document, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise expressly and specifically defined. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise expressly and specifically defined.

[0054] In this document, when referring to numerical intervals (i.e., numerical ranges), unless otherwise specified, the distribution of selectable values ​​within a numerical interval is considered continuous, and includes the two endpoints (i.e., the minimum and maximum values) of the numerical interval, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in this numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, and other numerical interval types.

[0055] In this document, temperature parameters are used. Unless otherwise specified, both isothermal processing and processing within a certain temperature range are permitted. The isothermal processing allows temperature fluctuations within the precision range controlled by the instrument.

[0056] Based on the above technical problems, in a first aspect, some embodiments of this application provide a supported catalyst for the selective hydrodeoxygenation of furfural in the gas phase; the supported catalyst includes: a support, and an active component supported on the support, the active component including molybdenum oxide.

[0057] In supported catalysts, the support plays the role of carrying the active components. It has high mechanical strength and large specific surface area, which can effectively enhance the mechanical strength and activity of the supported catalyst.

[0058] The active component refers to the component that directly catalyzes the hydrodeoxygenation reaction. Different active components have different selectivity for the hydrodeoxygenation products.

[0059] In the supported catalyst provided in this application embodiment, by loading an active component, including molybdenum oxide, onto a support, the oxygen vacancies on the molybdenum oxide catalyst can capture oxygen on the carbonyl group of furfural during use. Furthermore, the selectivity of the corresponding hydrodeoxygenation products can be improved by adjusting the content of molybdenum in the supported catalyst and the catalytic reaction conditions, etc., for different hydrodeoxygenation products. Meanwhile, compared with related technologies that use Cu... +Compared with the supported catalyst prepared by adding alkali metal and / or alkaline earth metal as a promoter to the active component, molybdenum oxide has a stable structure, is not easily over-reduced to reduce the active component, and has a large atomic number and is not easily migrated, so the catalyst is not easily sintered and is relatively stable. Therefore, it can solve the problems in the related technology such as poor selectivity of the hydrogenation deoxygenation product in the preparation of furfural, easy sintering and crystal growth of the catalyst, reduced activity, poor stability, multiple separation and regeneration required, and large environmental pollution.

[0060] In summary, the supported catalyst provided by the embodiments of the present application has high activity, high selectivity of the hydrogenation deoxygenation product, and relatively high catalytic stability, and has great application value.

[0061] In some embodiments, in the supported catalyst, the mass percentage of molybdenum element contained in the active component is 0.1 wt% to 40 wt%. For example, the mass percentage of molybdenum element contained in the active component can be 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 10 wt%, 16 wt%, 32 wt%, 40 wt%, etc.

[0062] In these embodiments, by controlling the mass percentage of molybdenum element contained in the active component within the range of 0.1 wt% to 40 wt%, when it is applied to the gas-phase hydrogenation deoxygenation of furfural to produce 2-methylfuran, the loading is more appropriate, which can ensure relatively high catalytic activity and prevent continuous hydrogenation and further hydrogenolysis based on 2-methylfuran caused by too high loading, resulting in reduced selectivity.

[0063] Furthermore, the mass percentage of molybdenum element contained in the active component is 0.5 wt% to 16 wt%.

[0064] In some embodiments, the molecular formula of the molybdenum oxide is expressed as MoO x , where 0 < x ≤ 3.

[0065] In these embodiments, the molecular formula of the molybdenum oxide is MoO x , where when 0 < x ≤ 3, the selectivity of 2-methylfuran can be maximally improved.

[0066] Among them, the specific selection of the above carrier is not limited, as long as the carrier can meet relatively high mechanical strength and large specific surface area, which is convenient for improving the mechanical strength and activity of the supported catalyst, it is within the protection scope of the present application.

[0067] In some embodiments, the carrier is selected from one or more of TiO2, SiO2, MCM-41, ZrO2, Al2O3, MgO, and CeO2.

[0068] For example, the support can be a single-component support, in which case the support is TiO2, SiO2, MCM-41, ZrO2, Al2O3, MgO or CeO2; or, the support can be a composite support, in which case the support can be composed of two or more components selected from TiO2, SiO2, MCM-41, ZrO2, Al2O3, MgO and CeO2.

[0069] The supported catalyst can be written in the form of active component / support. In this case, when the support is a single-component support, the supported catalyst can be MoO. x / TiO2、MoOx / ZrO2、MoO x / SiO2、MoO x / MCM-41、MoO x / Al2O3、MoO x / MgO or MoO x / CeO2; In the case where the support is a composite support, the supported catalyst can be MoO2. x / SiO2-Al2O3、MoO x / TiO2-Al2O3 or MoO x / MgO-Al2O3, etc.

[0070] Further, the support is one or more selected from TiO2, ZrO2, MCM-41, SiO2, MgO, and Al2O3. Further, the supported catalyst includes: MoO x / TiO2、MoO x / MCM-41、MoO x / ZrO2、MoO x / SiO2、MoO x / MgO and MoO x One or more of Al2O3.

[0071] The aforementioned supports can be obtained commercially or in-house, and no specific limitations are imposed here. All supports composed of the aforementioned compounds with different crystal forms, specific surface areas, and textures are within the scope of protection of this application.

[0072] Secondly, some embodiments of this application provide a method for preparing a supported catalyst as described in the first aspect, comprising:

[0073] The supported catalyst was prepared by loading the active component onto the support through impregnation or co-precipitation.

[0074] In some embodiments, the supported catalyst is prepared by impregnation, in which the active component is loaded onto a support, including the following steps S11) to S13):

[0075] S11) Prepare a precursor solution of the active component;

[0076] The precursor of the active component can be any molybdenum source capable of preparing molybdenum oxide. No specific limitations are made on its selection. All molybdenum sources capable of preparing the above-mentioned molybdenum oxide are within the scope of protection of this application.

[0077] In some embodiments, the precursor of the active component may include at least one selected from molybdate, molybdic acid, and molybdenum oxide. Optionally, the precursor of the active component may include ammonium heptamolybdate ((NH4)6Mo7O 24 Ammonium molybdate ((NH4)2MoO4), sodium molybdate (Na2MoO4), molybdenum pentachloride (MoCl5), sodium phosphomolybdate (Na3PMo) 12 O 40 ), 12-silicomolybdic acid (H4SiMo) 12 O 40 One or more of molybdenum trioxide (MoO3) and molybdenum trioxide (MoO3).

[0078] Furthermore, the precursor of this active component includes: ammonium heptamolybdate ((NH4)6Mo7O 24 It can be one or more of the following: ammonium molybdate ((NH4)2MoO4) and sodium molybdate (Na2MoO4).

[0079] In some embodiments, the solvent used in the precursor solution can dissolve the precursor without reacting with it, and can be volatilized and removed during the drying and calcination process; no specific limitation is made here.

[0080] In some embodiments of this application, the solvent used for the precursor solution can be water, ammonia, or cyclohexane. In these embodiments, using water as the solvent has the advantages of being economical, environmentally friendly, inexpensive, and readily available.

[0081] In some embodiments, the concentration of the precursor of the active component in the precursor solution can be from 0.001 g / mL to 0.4 g / mL. For example, the concentration can be 0.001 g / mL, 0.004 g / mL, 0.008 g / mL, 0.016 g / mL, 0.032 g / mL, 0.064 g / mL, 0.12 g / mL, 0.24 g / mL, 0.36 g / mL, or 0.4 g / mL, etc. Optionally, the concentration of the precursor is from 0.003 g / mL to 0.36 g / mL.

[0082] S12) Under stirring, the precursor solution is dropped onto the carrier so that the precursor solution adheres to the carrier;

[0083] By directly impregnating the carrier with the precursor solution through dropwise addition, unnecessary waste of the precursor solution can be avoided.

[0084] In some embodiments, a glass rod can be used to stir the precursor solution and the carrier, and stirring can continue for 10 min to 60 min after the addition is completed. Optionally, stirring can continue for 10 min to 30 min.

[0085] In these embodiments, impregnation uniformity can be improved, thereby enabling the precursor solution to be uniformly loaded on the carrier.

[0086] To further ensure uniform loading of the precursor solution on the carrier, in some alternative embodiments, the preparation method may further include, during impregnation, ultrasonic treatment of the impregnated precursor solution and carrier to allow the precursor solution to diffuse within the carrier.

[0087] In some embodiments, the ultrasonic treatment power is 50W to 250W, and the time is 0.5h to 4h. Optionally, the ultrasonic treatment power is 100W to 200W, and the time is 1h to 2h.

[0088] S13) The supported catalyst is prepared by drying, calcining and granulating the support with the precursor solution attached.

[0089] In some embodiments, the supported catalyst is prepared by co-precipitation, which loads the active component onto a support. This process may include:

[0090] A mixed solution of the precursor of the active component and the support was prepared, and the pH value was adjusted to cause the precursor to form a hydroxide precipitate.

[0091] The precipitate was filtered, dried, calcined, and granulated to prepare the supported catalyst.

[0092] In these embodiments, the precursor of the active component can be found in the above description of the preparation of supported catalysts by impregnation, and the precursor of the support can be selected according to the chemical composition of the support.

[0093] For example, when the support is silica, the precursor of the support can be tetraethyl orthosilicate. In this case, in order to generate hydroxide precipitates from both precursors, the pH value can be adjusted to acidity.

[0094] In the above embodiments, the carrier can be purchased commercially or obtained by self-production, and no specific limitation is made here.

[0095] In some embodiments, the drying temperature can be 90°C to 120°C, and the drying time can be 8 hours to 24 hours.

[0096] Optionally, the drying temperature is 100℃~120℃, such as 100℃, 110℃ or 120℃; the time is 12h~18h, such as 12h, 13h, 14h, 15h, 16h, 17h or 18h.

[0097] In other embodiments, the calcination temperature can be 400℃ to 900℃, and the time can be 3h to 8h. Optionally, the calcination temperature is 450℃ to 700℃, such as 450℃, 500℃, 550℃, 600℃, 650℃, or 700℃; and the time is 4h to 8h, such as 4h, 5h, 6h, 7h, or 8h.

[0098] In some embodiments, the mesh size of the supported catalyst for tableting and granulation is 10 to 100 mesh.

[0099] The preparation method of the supported catalyst provided in the embodiments of this application is simple and easy to operate, and can make the active components uniformly loaded on the support.

[0100] In this process, the main component of the supported catalyst is +6 molybdenum oxide. In order to maintain the high catalytic activity of molybdenum oxide, in some embodiments, the preparation method further includes activating the supported catalyst.

[0101] In some embodiments, activation of the supported catalyst includes:

[0102] The supported catalyst is pre-reduced to activate it.

[0103] In some embodiments, a reducing gas may be used to pre-reduce the supported catalyst, the reducing gas including hydrogen or a mixture of hydrogen and an inert gas.

[0104] Optionally, hydrogen accounts for 20% to 100% of the volume of the reducing gas.

[0105] Taking a mixture of hydrogen and an inert gas as an example, the reducing gas can be expressed as a volume percentage of H2 / inert gas. If the reducing gas is a mixture of hydrogen and nitrogen, and the volume percentage of hydrogen is 20%, then the reducing gas can be 20% H2 / N2. Further, if the volume percentage of hydrogen is 30% to 100%, the reducing gas can be, for example, 30% H2 / N2, 50% H2 / N2, 50% H2 / Ar, 50% H2 / He, 70% H2 / N2, 90% H2 / N2, or 100% H2 (in which case the purity of hydrogen can be 99.9%), etc.

[0106] Optionally, the temperature of the pre-reduction treatment is 200℃ to 600℃, and the time is 0.5h to 5h. More optionally, the pre-reduction temperature is 250℃ to 500℃, for example, 250℃, 300℃, 350℃, 400℃, 450℃, or 500℃; and the time is 1h to 3h, for example, 1h, 1.5h, 2h, 2.5h, or 3h.

[0107] Thirdly, some embodiments of this application provide a method for gas-phase hydrodeoxygenation of furfural using the supported catalyst as described in the first aspect, comprising the following steps S21) to S22):

[0108] S21) Vaporize furfural or furfural solution;

[0109] The furfural mentioned above can be pure furfural solution, and the furfural solution can be prepared by mixing a solvent and pure furfural solution.

[0110] In some embodiments, the solvent used to prepare the above-mentioned furfural solution may include one or more of the following: cyclopentyl methyl ether, 1,4-dioxane, anisole, cyclopentane, toluene, methanol, ethanol, n-propanol, isopropanol, n-butanol, and isobutanol.

[0111] In some embodiments, in the above-mentioned furfural solution, the molar ratio of the solvent used to prepare the furfural solution to furfural is greater than 0 and less than or equal to 300.

[0112] S22) The furfural or furfural solution after gasification is subjected to a hydrodeoxygenation reaction under the catalysis of a supported catalyst to prepare the hydrodeoxygenation product.

[0113] In some embodiments, the hydrodeoxygenation product is 2-methylfuran; hydrogen is used to contact the vaporized furfural or furfural solution to induce a hydrodeoxygenation reaction, wherein the molar ratio of hydrogen to furfural is (30–500):1. Optionally, the molar ratio of hydrogen to furfural is (100–500):1.

[0114] In these embodiments, the molar ratio of hydrogen to furfural allows for sufficient furfural vaporization, and an excess of hydrogen promotes the conversion of furfural to 2-methylfuran.

[0115] In some embodiments, the temperature of the above-mentioned hydrodeoxygenation reaction is 200°C to 600°C, the pressure is 0.1 MPa to 1 MPa, and the total space velocity is 800 mL h⁻¹. -1 g cat -1 ~90000mL h -1 g cat -1 Optionally, the hydrodeoxygenation reaction is carried out at a temperature of 200℃ to 450℃, a pressure of 0.1 MPa to 0.5 MPa, and a total space velocity of 1000 mL / h. -1 g cat -1 ~80000mL h -1 g cat -1 .

[0116] Space velocity refers to the amount of gas processed per unit volume of catalyst per unit time under specified conditions.

[0117] A higher space velocity results in a shorter residence time, a lower reaction depth, but a higher throughput; a lower space velocity results in a longer residence time, a higher reaction depth, but a lower throughput.

[0118] In these embodiments, the reaction can be carried out in a continuous flow fixed-bed reactor, thereby allowing for control of the reaction depth by controlling the space velocity, and thus effective control over the products and selectivity of furfural gas-phase hydrodeoxygenation.

[0119] Taking 2-methylfuran, the product of the aforementioned hydrodeoxygenation, as an example, 2-methylfuran is an important chemical raw material that can be used to synthesize a series of organic chemical products, such as pentadiene, pentanediol, acetylacetonol, and related ketones. It is also an important pharmaceutical intermediate used in the production of drugs such as vitamin B1, chloroquine phosphate, and primamethane phosphate. Furthermore, 2-methylfuran possesses a high octane number (RON) of approximately 131, high energy density, and low water solubility, making it a very promising gasoline additive. Currently, the preparation of 2-methylfuran suffers from low selectivity, which hinders its application in the aforementioned fields. This application's embodiments, through catalyst improvement and the use of a continuous flow fixed-bed reactor for 2-methylfuran preparation, significantly improve the selectivity of 2-methylfuran, providing conditions for its application in these fields.

[0120] In order to objectively evaluate the technical effects of the embodiments of this application, this application will be described in detail by way of example through the following embodiments and comparative examples.

[0121] In the following examples and comparative examples, all raw materials were commercially available, and to maintain the reliability of the experiments, the raw materials used in the following examples and comparative examples had the same physical and chemical parameters or were prepared by the same processing method.

[0122] Example 1

[0123] Preparation of 0.5 wt% MoO x / TiO2 catalyst (i.e., MoO) x Molybdenum accounts for a significant portion of MoO₂. x (The percentage of TiO2 by total mass is 0.5 wt%)

[0124] Step 1) Prepare by impregnation, weigh 0.04g (NH4)6Mo7O 24 Dissolve in 5 mL of water in a 10 mL centrifuge tube to obtain (NH4)6Mo7O 24 Solution;

[0125] Step 2) Weigh 5.0g of TiO2 and place it in a 100mL beaker;

[0126] Step 3) (NH4)6Mo7O 24 The solution was slowly added to the TiO2 support using a dropper while stirring with a glass rod. After the addition was complete, stirring was continued for 10 minutes, and then the solution was placed in an ultrasonic bath for 2 hours to allow for full diffusion.

[0127] Step 4) Load (NH4)6Mo7O in Step 3) 24 The carrier obtained after solution treatment was dried in a 110℃ forced-air drying oven for 12 hours, and then calcined in a tube furnace at 650℃ for 4 hours in flowing air (air flow rate of 60 mL / min) to obtain a carrier powder loaded with molybdenum oxide.

[0128] Step 5): Compress the carrier powder obtained in Step 4) into tablets at a pressure of 15 MPa, crush, and sieve to obtain 40-60 mesh particles to obtain 0.5 wt% MoO. x / TiO2 catalyst.

[0129] Example 2

[0130] Preparation of 4.0 wt% MoO x / SiO2 catalyst (i.e., MoO) x Molybdenum accounts for a significant portion of MoO₂ x The percentage of SiO2 by total mass is 4 wt%.

[0131] In Example 2, 4.0 wt% MoO x The preparation method of the SiO2 catalyst is the same as that of the 0.5wt% MoO catalyst in Example 1. x The preparation methods for TiO2 catalysts are basically the same, the difference being:

[0132] In step 1), weigh out 0.36g of (NH4)6Mo7O 24 Dissolve in 15 mL of water to obtain (NH4)6Mo7O 24 Solution;

[0133] In step 2), weigh 5.0g of SiO2 and place it in a 100mL beaker.

[0134] Example 3

[0135] Preparation of 4.0 wt% MoO x / Al2O3 catalyst (i.e., MoO) x Molybdenum accounts for a significant portion of MoO₂ x (The percentage of total Al2O3 by mass is 4 wt%)

[0136] In Example 3, 4.0 wt% MoO x The preparation method of the Al2O3 catalyst is the same as that of the 0.5wt% MoO catalyst in Example 1. x The preparation methods for TiO2 catalysts are basically the same, the difference being:

[0137] In step 1), weigh out 0.36g of (NH4)6Mo7O 24 Dissolve in 10 mL of water to obtain (NH4)6Mo7O 24 Solution;

[0138] In step 2), weigh 5.0g of Al2O3 and place it in a 100mL beaker.

[0139] Example 4

[0140] Preparation of 4.0 wt% MoO x / ZrO2 catalyst (i.e., MoO) x Molybdenum accounts for a significant portion of MoO₂ x The percentage of total ZrO2 by mass is 4 wt%.

[0141] In Example 4, 4.0 wt% MoO x The preparation method of the ZrO2 catalyst is the same as that of the 0.5wt% MoO catalyst in Example 1. x The preparation methods for TiO2 catalysts are basically the same, the difference being:

[0142] In step 1), weigh out 0.36g of (NH4)6Mo7O 24 Dissolve in 3 mL of water to obtain (NH4)6Mo7O 24 Solution;

[0143] In step 2), weigh 5.0g of ZrO2 and place it in a 100mL beaker.

[0144] Example 5

[0145] Preparation of 4.0 wt% MoO x / MgO catalyst (i.e., MoO) x Molybdenum accounts for a significant portion of MoO₂ x (The percentage of MgO by total mass is 4 wt%)

[0146] The preparation method of the 4.0 wt% MoOx / MgO catalyst in Example 5 is the same as that of the 0.5 wt% MoOx / MgO catalyst in Example 1. x The preparation methods for TiO2 catalysts are basically the same, the difference being:

[0147] In step 1), weigh out 0.36g of (NH4)6Mo7O 24 Dissolve in 4 mL of water to obtain (NH4)6Mo7O 24 Solution;

[0148] In step 2), weigh 5.0g of MgO and place it in a 100mL beaker.

[0149] Example 6

[0150] Preparation of 0.5 wt% MoO x / MCM-41 catalyst (i.e., MoO) x Molybdenum accounts for a significant portion of MoO₂ x (The percentage of the total mass of MCM-41 is 0.5 wt%):

[0151] In Example 6, 0.5 wt% MoO x The preparation method of / MCM-41 catalyst is the same as that of 0.5wt% MoO in Example 1. x The preparation methods for TiO2 catalysts are basically the same, the difference being:

[0152] In step 1), weigh out 0.0018 g of (NH4)6Mo7O 24 Dissolve in 20 mL of water in a 25 mL centrifuge tube to obtain (NH4)6Mo7O 24 Solution;

[0153] In step 2), tetraethyl orthosilicate is used as the silicon source, according to SiO2, [C 16 H 33The molar ratio of N(CH3)3]Br to H2O is 1.0:0.20:160. 0.3g of (NH4)6Mo7O is weighed out. 24 62.5g tetraethyl orthosilicate, 21.8g [C 16 H 33 N(CH3)3]Br, and 484 mL of water was added to a 1000 mL beaker. The mixture was magnetically stirred, and concentrated hydrochloric acid was added dropwise to adjust the pH to 0.5. Stirring continued for 5 days at room temperature. The mixture was filtered, washed multiple times, dried in an oven for 12 hours, and calcined at 650 °C for 8 hours in flowing air (air flow rate 60 mL / min) to prepare MCM-41. 5.0 g of MCM-41 was weighed and placed in a 100 mL beaker.

[0154] Example 7

[0155] Preparation of 0.5 wt% MoO x -MCM-41 catalyst (i.e., MoO) x Molybdenum accounts for a significant portion of MoO₂ x (The percentage of the total mass of MCM-41 is 0.5 wt%):

[0156] Prepared by precipitation (coprecipitation) method, with (NH4)6Mo7O 24 Molybdenum is the molybdenum source, and tetraethyl orthosilicate is the silicon source, according to the formula: MoO3, SiO2, [C 16 H 33 The molar ratio of N(CH3)3]Br to H2O is 0.025:1.0:0.20:160. 0.3 g of (NH4)6Mo7O was weighed out. 24 62.5g tetraethyl orthosilicate, 21.8g [C 16 H 33 [N(CH3)3]Br and 484 mL of water were added to a 1000 mL beaker, stirred magnetically, and concentrated hydrochloric acid was added dropwise to adjust the pH to 0.5. Stirring was continued for 5 days at room temperature. The mixture was filtered, washed multiple times, dried in an oven for 12 hours, and calcined at 650 °C for 8 hours in flowing air (air flow rate of 60 mL / min). The resulting powder was compressed into tablets under a pressure of 15 MPa, crushed, and sieved to obtain catalyst particles of 40–60 mesh.

[0157] Example 8

[0158] Preparation of 4.0 wt% MoO x / TiO2 catalyst (i.e., MoO) x Molybdenum accounts for a significant portion of MoO₂ x (The percentage of TiO2 by total mass is 4.0 wt%)

[0159] In Example 8, 4.0 wt% MoO xThe preparation method of the TiO2 catalyst is the same as that of the 0.5wt% MoO catalyst in Example 1. x The preparation methods for TiO2 catalysts are basically the same, the difference being:

[0160] In step 1), weigh out 0.36g of (NH4)6Mo7O 24 Dissolve in 5 mL of water in a 10 mL centrifuge tube to obtain (NH4)6Mo7O 24 Solution.

[0161] Test case

[0162] The catalysts provided in Examples 1-8 above were used to catalyze the gas-phase hydrogenation of furfural to 2-methylfuran. The catalytic performance of different supports under the same conditions, as well as the reaction of the same support under different activation conditions, specifications, catalyst loading, preparation methods, and different reaction conditions, were evaluated. The specific test conditions and results are as follows:

[0163] The gas-phase hydrogenation of furfural to 2-methylfuran was carried out in a continuous flow fixed-bed reactor under atmospheric pressure. The reaction tube was a U-shaped quartz tube (50 cm in length × 9 mm in inner diameter). The specific operation process is as follows:

[0164] 200 mg of each of the catalysts prepared in Examples 1 to 8 were packed into a U-shaped quartz tube and sandwiched between two layers of quartz wool to perform a pre-reduction treatment on the catalysts in order to activate the catalysts prepared in Examples 1 to 8.

[0165] After activation, furfural or its solution is injected into the vaporization chamber using a high-pressure injection pump. The furfural or its solution vaporized in the vaporization chamber enters the reaction tube along with hydrogen. The vaporization chamber and all pipelines are wrapped with heating belts. The temperature of the heating belts is adjusted to control the reaction temperature, as well as the partial pressures of furfural, solvent, and hydrogen, and the total space velocity. Samples are taken for analysis after different reaction times (the reactants and products are analyzed online via GC (Agilent 7890) autosampler, using an HP-5 capillary column and an FID detector). The detection results are shown in Tables 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 below.

[0166] Test Example 1: Catalytic performance analysis of catalysts with the same support over reaction time:

[0167] The specific test conditions were as follows: 4.0 wt% MoO prepared in Example 8 was used. x200 mg of TiO2 catalyst was packed into the reaction tube. H2 was introduced during the pre-reduction treatment at a flow rate of 25 mL / min, a temperature of 300 °C, and a time of 2 h. In the hydrogenation deoxygenation of furfural to 2-methylfuran, a mixed solution of furfural and cyclopentyl methyl ether (molar ratio of cyclopentyl methyl ether to furfural was 8:1) was injected into the vaporization chamber at a rate of 0.5 mL / h. After vaporization in the vaporization chamber, furfural and cyclopentyl methyl ether, along with hydrogen, entered the reaction tube. The vaporization chamber and all pipelines were surrounded by a heating belt at a temperature of 180 °C. The reaction temperature was 300 °C, and the partial pressures of furfural, cyclopentyl methyl ether, and hydrogen were 0.3 kPa, 2.3 kPa, and 98.7 kPa, respectively. The total space velocity was 18500 mL / h. - 1 g cat -1 The changes in the production of 2-methylfuran by the gas-phase hydrogenation of furfural with reaction time are shown in Table 1 below:

[0168] Table 1. Catalytic performance of catalysts over reaction time

[0169]

[0170]

[0171] As shown in Table 1, under the above reaction conditions, the catalyst provided in Example 8 was used to catalyze the hydrogenation deoxygenation of furfural to 2-methylfuran. The catalyst reached a stable state after about 2 hours of reaction, and the selectivity of 2-methylfuran could reach 97%.

[0172] Test Example 2: Analysis of the effect of different total space velocities on the reaction performance of furfural hydrogenation to 2-methylfuran when using the catalyst provided in Example 8:

[0173] The test conditions in Test Example 2 are basically the same as those in Test Example 1, except that the total space velocity is adjusted to 1850 mL h⁻¹. -1 g cat -1 4600mL h -1 g cat -1 and 18500mL h -1 g cat -1 Tests revealed that 4.0 wt% MoO₂ under different total space velocities... x The TiO2-catalyzed gas-phase hydrogenation of furfural to 2-methylfuran is shown in Table 2 below.

[0174] Table 2. Effect of different total space velocities on the reaction performance of furfural hydrogenation to 2-methylfuran

[0175]

[0176] As shown in Table 2, under the above reaction conditions, the conversion rate of furfural decreases and the selectivity of 2-methylfuran decreases with increasing total space velocity. Even when the furfural conversion rate is relatively high (approximately 65%), the selectivity of 2-methylfuran can still reach 90%. Other hydrogenation deoxygenation products are 2-methyltetrahydrofuran, pentanol, and pentane.

[0177] Test Example 3: Catalytic performance analysis using different supports under the same reaction conditions:

[0178] The test conditions in Test Example 3 are basically the same as those in Test Example 1. The difference is that the catalysts provided in Examples 2, 3, 4, 5, and 8 are used to catalyze the gas-phase hydrogenation of furfural. The test results after 0.7 h of reaction are compared as shown in Table 3 below:

[0179] Table 3. Catalytic performance of different supports under the same reaction conditions

[0180]

[0181] As shown in Table 3, under the above reaction conditions, 2-methylfuran can be generated with high selectivity on different supports.

[0182] Test Example 4: Analysis of the impact of different preparation methods on catalyst performance:

[0183] The test conditions in Test Example 4 are basically the same as those in Test Example 1. The difference is that the catalysts provided in Example 7 and Example 6 are used for comparative analysis. The results are shown in Table 4 below:

[0184] Table 4. Effect of different preparation methods on catalyst performance

[0185]

[0186] As shown in Table 4, under the above reaction conditions, the catalysts prepared by impregnation and coprecipitation have no significant effect on the conversion rate of furfural and the selectivity of 2-methylfuran.

[0187] Test Example 5: Effect of Mo loading on the performance of furfural hydrogenation to 2-methylfuran:

[0188] The test conditions in Test Example 5 were basically the same as those in Test Example 1, except that the mass percentage of Mo in the catalyst was adjusted to 0.09 wt%, 0.49 wt%, 3.80 wt%, and 9.91 wt%, respectively. The specific test results are shown in Table 5 below.

[0189] Table 5. Effect of Mo loading on the performance of furfural hydrogenation to 2-methylfuran

[0190]

[0191] Table 5 shows that under the above reaction conditions, the higher the Mo loading, the higher the conversion rate of furfural and the higher the yield of 2-methylfuran. However, the selectivity of 2-methylfuran first increases and then decreases with increasing Mo loading, reaching its optimal value at a Mo loading of 3.80 wt%. In this test example, the other hydrodeoxygenation products were 2-methyltetrahydrofuran, pentanol, and pentane.

[0192] Test Example 6: Analysis of the effect of the solvent used in the furfural solution on the performance of the gas-phase hydrogenation of furfural to 2-methylfuran:

[0193] The test conditions in Test Example 6 were basically the same as those in Test Example 1, except that the catalyst provided in Example 1 was used to catalyze the gas-phase hydrogenation of furfural to 2-methylfuran. The solvents used in the furfural solution were ethanol and cyclopentyl methyl ether. When ethanol was used as the solvent in the furfural solution, the partial pressures of furfural, ethanol, and hydrogen during the reaction were 0.3 kPa, 4.7 kPa, and 96.3 kPa, respectively, and the total space velocity was 18900 mL h⁻¹. -1 g cat -1 When cyclopentyl methyl ether was used as the solvent in the furfural solution, the partial pressures of furfural, cyclopentyl methyl ether, and hydrogen, as well as the total space velocity, were the same as in Test Example 1. Specific test results are shown in Table 6 below:

[0194] Table 6. Effect of the solvent used in the furfural solution on the performance of the gas-phase hydrogenation of furfural to 2-methylfuran.

[0195]

[0196] Table 6 shows that when cyclopentyl methyl ether is used as the solvent, the selectivity for the gas-phase hydrogenation of furfural to 2-methylfuran is higher. When ethanol is used as the solvent, the conversion rate of furfural and the yield of 2-methylfuran are higher, but the selectivity is poor, and some furfural is converted to furfuryl alcohol. This may be because ethanol can also provide a hydrogen source for the hydrogenation of furfural. In this test example, other hydrogenation deoxygenation products were 2-methyltetrahydrofuran, pentanol, and pentane.

[0197] Test Example 7: Analysis of the Influence of Different Pre-reduction Conditions on the Reaction Performance of Furfural Hydrogenation to 2-Methylfuran:

[0198] The test conditions in Test Example 7 were basically the same as those in Test Example 1, except that the catalyst provided in Example 1 was used, and the pre-reduction temperatures were 300℃, 340℃, 360℃, and 400℃, respectively. After the pre-reduction was completed, the temperature was lowered to 300℃ in a pre-reduction atmosphere for the hydrodeoxygenation reaction. The specific test results are shown in Table 7 below:

[0199] Table 7. Effects of different pre-reduction conditions on the performance of furfural hydrogenation to 2-methylfuran

[0200]

[0201] As shown in Table 7, under the above reaction conditions, the higher the pre-reduction temperature, the lower the selectivity of 2-methylfuran, the higher the selectivity of furfuryl alcohol, and the no significant effect on the conversion rate of furfural. In this test example, the other hydrogenation deoxygenation products were 2-methyltetrahydrofuran, pentanol, and pentane.

[0202] Test Example 8: Analysis of the effect of reaction temperature on the performance of furfural hydrogenation to 2-methylfuran:

[0203] The test conditions in Test Example 8 were basically the same as those in Test Example 1, except that the pre-reduction temperature was 450℃, and after the pre-reduction, the temperature was lowered to 300℃ in a pre-reduction atmosphere for the hydrodeoxygenation reaction. After the reaction reached stability for a period of time, it was held for a period of time, and then the temperature was successively increased to 315℃, 330℃, and 345℃ for further reaction. The final reaction test results are shown in Table 8 below:

[0204] Table 8. Effect of reaction temperature on the performance of furfural hydrogenation to 2-methylfuran

[0205]

[0206] As shown in Table 8, under the above reaction conditions, the conversion rate of furfural increases with increasing reaction temperature, while the selectivity of 2-methylfuran decreases. Furfural is more prone to over-hydrogenation. The optimal selectivity is achieved at a reaction temperature of 300℃, while the optimal conversion rate and yield of 2-methylfuran are observed at a reaction temperature of 345℃, with a selectivity still exceeding 90%. In this test example, other hydrogenation deoxygenation products were 2-methyltetrahydrofuran, pentanol, and pentane.

[0207] Test Example 9: Analysis of the effect of different total space velocities on the performance of furfural hydrogenation to 2-methylfuran using the catalyst provided in Example 1:

[0208] The test conditions in Test Example 9 were basically the same as those in Test Example 1, except that the catalyst provided in Example 1 was used to catalyze the hydrogenation deoxygenation of furfural to 2-methylfuran. The furfural solution was a mixed solution of furfural and ethanol. During the reaction, the partial pressures of furfural, ethanol, and hydrogen were 0.3 kPa, 4.7 kPa, and 96.3 kPa, respectively, and the total space velocity was 6300 mL h⁻¹. -1 g cat -1 18900mL h -1 g cat -1 and 75600mL h -1 g cat -1 The test results at different total airspeeds are shown in Table 9 below:

[0209] Table 9. Effect of different total space velocities on the performance of furfural hydrogenation to 2-methylfuran

[0210]

[0211] As shown in Table 9, under the above reaction conditions, with the increase of total space velocity, the conversion rate of furfural decreases, the selectivity of 2-methylfuran decreases significantly, and the selectivity of furfuryl alcohol increases, gradually becoming the main product. In this test example, the other hydrogenation deoxygenation products were 2-methyltetrahydrofuran and tetrahydrofurfuryl alcohol.

[0212] Test Example 10: Effects of different carrier specifications on MoO x Analysis of the effect of TiO2 on the performance of furfural hydrogenation to 2-methylfuran:

[0213] The test conditions in Test Example 10 were basically the same as those in Test Example 1, except that commercially available anatase TiO2(R) and P25 support were used, and the catalyst loading and preparation method were the same as those provided in Example 8. Specific test results are shown in Table 10 below:

[0214] Table 10. Effects of different carrier specifications on MoO x The effect of TiO2 catalytic performance on the hydrogenation of furfural to 2-methylfuran

[0215]

[0216] Table 10 shows that different specifications of TiO2 supports affect MoO2. x The performance of TiO2-catalyzed gas-phase hydrogenation of furfural to 2-methylfuran was not significantly affected. In this test example, other hydrogenation deoxygenation products were 2-methyltetrahydrofuran, pentanol, and pentane.

[0217] Comparative Example 1: Preparation of catalyst using quartz sand to replace the support:

[0218] (NH4)6Mo7O 24 The catalyst was placed directly in a tube furnace and calcined at 650°C for 4 hours in flowing air (air flow rate of 60 mL / min). 8.0 mg of the calcined powder was then physically mixed with 1 g of quartz sand and ground thoroughly. The resulting catalyst was labeled as MoOx-silica-mix.

[0219] Test Example 11: Analysis of the impact of replacing the support with a non-supported material on catalytic performance:

[0220] The test conditions in Test Example 11 were basically the same as those in Test Example 1, except that the MoOx-silica-mix catalyst was pre-reduced in H2 at 600℃ and a flow rate of 25 mL / min for 0.5 h, and the total space velocity in the gas-phase hydrogenation of furfural to 2-methylfuran was 60,000 mL / h. -1 g cat -1 The test was conducted. The specific test results are shown in Table 11 below:

[0221] Table 11. Effect of replacing the support with a non-supported material on catalytic performance

[0222] Reaction time (min) Furfural conversion rate (%) 2-Methylfuran selectivity (%) 40 4.7 98.6 70 1.6 98.3 100 1.3 98.5 130 <1 98.6

[0223] As shown in Table 11, under the above reaction conditions, MoOx-silica-mix can catalyze the gas-phase hydrogenation of furfural to 2-methylfuran with high selectivity, but it quickly deactivates and cannot meet the catalytic requirements.

[0224] Comparative Example 2: The support (TiO2) in this application was used directly as a catalyst after calcination without loading molybdenum oxide.

[0225] Take 2g of TiO2 and place it directly in a tube furnace and calcine it at 650℃ for 4h in flowing air (air flow rate of 60mL / min). Press the obtained powder into tablets under a pressure of 15MPa, crush it, and sieve it to obtain 40-60 mesh TiO2 particles.

[0226] Comparative Example 3: The support (SiO2) in this application was used directly as a catalyst after calcination without loading molybdenum oxide.

[0227] The catalyst preparation methods in Comparative Example 3 and Comparative Example 2 are basically the same, except that SiO2 support is used as the catalyst.

[0228] Comparative Example 4: The support (Al2O3) in this application was used directly as a catalyst after calcination without loading molybdenum oxide.

[0229] The catalyst preparation methods in Comparative Example 4 and Comparative Example 2 are basically the same, except that Al2O3 support is used as the catalyst.

[0230] Comparative Example 5: The support (ZrO2) in this application was used directly as a catalyst after calcination without molybdenum oxide loading.

[0231] The catalyst preparation methods in Comparative Example 5 and Comparative Example 2 are basically the same, except that ZrO2 support is used as the catalyst.

[0232] Comparative Example 6: The support (MgO) in this application was used directly as a catalyst after calcination without supporting molybdenum oxide.

[0233] The catalyst preparation methods in Comparative Example 6 and Comparative Example 2 are basically the same, except that MgO support is used as the catalyst.

[0234] Test Example 12: The specific surface area and catalytic performance of the catalysts provided in Comparative Examples 2-6 were analyzed.

[0235] The test conditions in Test Example 12 are basically the same as those in Test Example 3, except that the total space velocity is 18900 mL h⁻¹. -1 g cat -1 The specific test results are shown in Table 12 below:

[0236] Table 12. Effect of support on the catalytic performance of furfural gas-phase hydrogenation without molybdenum oxide loading.

[0237]

[0238]

[0239] As shown in Table 12, under the above reaction conditions, by using a support directly instead of a catalyst for catalysis, furfural can undergo transfer hydrogenation with an alcohol solvent on the support, with furfuryl alcohol being the main product. This differs from the products and selectivity obtained in Test Example 3 of this application, which used a catalyst supported on molybdenum oxide. This indicates that molybdenum oxide plays an activating role in the gas-phase hydrogenation deoxygenation of furfural to 2-methylfuran, thereby improving the selectivity of 2-methylfuran. In Test Example 12, the other hydrogenation deoxygenation product was tetrahydrofurfuryl alcohol.

[0240] In summary, the supported catalyst provided in this application embodiment consists of molybdenum oxide (MoO₂) as the active component. xThe catalyst consists of 0.1 wt% to 40 wt% of Mo and oxides acting as supports (such as TiO2, SiO2, MCM-41, ZrO2, Al2O3, MgO, and Al2O3-SiO2). In a continuous flow fixed-bed catalytic reactor, the catalyst of this application was used for the gas-phase hydrodeoxygenation of furfural, achieving the direct, highly selective (up to 97%) production of 2-methylfuran (e.g., MoO2) from furfural. x The catalyst can maintain furfural conversion above 60% (e.g., in Test Example 2 when the total space velocity is 1850 mL h⁻¹). -1 g cat -1 When the furfural conversion rate is 64.6%, the selectivity for 2-methylfuran in the product remains above 90%, and the content of byproducts such as furfuryl alcohol is below 10%, with stable performance. The catalyst of this application can be used for the direct production of 2-methylfuran by highly selective continuous hydrogenation of furfural.

[0241] In summary, the supported catalyst provided in this application has advantages such as high selectivity and stable catalytic performance, and can be used for large-scale production of 2-methylfuran. This creates conditions for the deep processing of furfural to produce 2-methylfuran, and solves the problems in related technologies where the production of 2-methylfuran has poor selectivity and the catalyst is prone to causing environmental pollution, which is not conducive to the deep processing of 2-methylfuran.

[0242] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0243] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for gas-phase hydrodeoxygenation of furfural using a supported catalyst, characterized in that, Comprising: Vaporizing furfural or a furfural solution; Subjecting the vaporized furfural or furfural solution to a hydrodeoxygenation reaction under the catalysis of a supported catalyst to prepare a hydrodeoxygenation product, wherein the hydrodeoxygenation product is 2-methylfuran; The supported catalyst includes: a carrier, and an active component supported on the carrier, the active component includes molybdenum oxide, and the molecular formula of the molybdenum oxide is expressed as MoOx, where 0 < x < 3; the carrier is selected from one or more of TiO2, SiO2, MCM-41, ZrO2, Al2O3, MgO, and CeO2.

2. The method according to claim 1, characterized in that, In the supported catalyst, the mass percentage content of molybdenum element contained in the active component is 0.1wt% - 40wt%.

3. The method according to claim 1, characterized in that, The preparation method of the supported catalyst includes: Using impregnation or co-precipitation to load the active component on the carrier to prepare the supported catalyst.

4. The method according to claim 3, characterized in that, The method of using impregnation to load the active component on the carrier to prepare the supported catalyst includes: Preparing a precursor solution of the active component; Under stirring, dropping the precursor solution onto the carrier so that the precursor solution adheres to the carrier; Drying, calcining, and tabletting and granulating the carrier attached with the precursor solution to prepare the supported catalyst.

5. The method according to claim 4, characterized in that, The precursor solution of the active component satisfies at least one of the following conditions: (1) The precursor of the active component includes at least one of molybdate, molybdic acid, and molybdenum oxide; (2) The concentration of the precursor of the active component in the precursor solution is 0.001g / mL - 0.4g / mL.

6. The method according to claim 4, characterized in that, The precursor of the active component includes one or more of ammonium heptamolybdate, ammonium molybdate, sodium molybdate, molybdenum pentachloride, sodium phosphomolybdate, 12-silicomolybdic acid, and molybdenum trioxide.

7. According to the method according to any one of claims 4 - 6, wherein The temperature of the drying is 90°C - 120°C, and the time is 8h - 24h; And / or, The temperature of the calcining is 400°C - 900°C, and the time is 3h - 8h; And / or, The mesh number of the tabletted and granulated supported catalyst is 10 - 100 mesh.

8. The method according to any one of claims 4-6, characterized in that, The preparation method further includes: activating the supported catalyst.

9. The method according to claim 8, characterized in that, The activation of the supported catalyst includes: Performing a pre-reduction treatment on the supported catalyst to activate the supported catalyst.

10. The method according to claim 9, characterized in that, Using a reducing gas to perform a pre-reduction treatment on the supported catalyst, and the reducing gas includes: hydrogen or a mixed gas of hydrogen and an inert gas.

11. The method according to claim 10, characterized in that, In the reducing gas, the volume ratio of hydrogen is 20% - 100%.

12. The method according to claim 10, characterized in that, The temperature of the pre-reduction treatment is 200°C - 600°C, and the time is 0.5h - 5h.

13. According to the method according to claim 1, wherein Using hydrogen to contact the vaporized furfural or furfural solution to cause the vaporized furfural or furfural solution to undergo a hydrodeoxygenation reaction, and the molar ratio of hydrogen to furfural is (30 - 500):

1.

14. The method according to claim 1 or 13, characterized in that, The hydrodeoxygenation reaction was carried out at a temperature of 200℃ to 600℃, a pressure of 0.1 MPa to 1 MPa, and a total space velocity of 800 mL·h. -1 ·g cat -1 ~90000 mL·h -1 ·g cat -1 .

15. The method according to claim 1 or 13, characterized in that, The solvents used to prepare the furfural solution include one or more of the following: cyclopentyl methyl ether, 1,4-dioxane, anisole, cyclopentane, toluene, methanol, ethanol, n-propanol, isopropanol, n-butanol, and isobutanol.

16. The method according to claim 15, characterized in that, In the furfural solution, the molar ratio of the solvent used to prepare the furfural solution to furfural is greater than 0 and less than or equal to 300.

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