Dehydrogenation catalysts and precursors thereof, methods of making, use and dehydrogenation reactions

Abstract

The application discloses a dehydrogenation catalyst and a precursor, a preparation method, application and a dehydrogenation reaction of the dehydrogenation catalyst. The preparation method of the dehydrogenation catalyst precursor comprises the following steps: S1: adding a precipitant solution into a mixed solution to perform a precipitation reaction, so as to obtain a slurry; wherein the mixed solution is a mixed solution of a metal salt solution and a colloidal silica solution, and the metal salt solution comprises a copper salt; the end point pH value of the precipitation reaction ranges from 7 to 11; S2: performing post-treatment on the slurry to obtain the dehydrogenation catalyst precursor. The dehydrogenation catalyst obtained by reducing the dehydrogenation catalyst precursor has a large specific surface area, high dispersity and excellent catalytic activity, and when the dehydrogenation catalyst is used for catalyzing a dehydrogenation reaction of methyl isobutyl carbinol to prepare methyl isobutyl ketone, the dehydrogenation catalyst has high conversion rate and selectivity.

Description

Technical Field

[0001] This invention relates to a dehydrogenation catalyst and its precursor, preparation method, application and dehydrogenation reaction. Background Technology

[0002] Methyl isobutyl ketone (MIBK) is one of the most important acetone derivatives. As an excellent chemical intermediate and medium-boiling-point organic solvent, it is mainly used as a high-grade coating solvent in the automotive, aerospace, and home decoration industries; a dewaxing agent for lubricating oils; an extractant and diluent for organic synthesis; a surfactant; and a rubber antioxidant for tires.

[0003] Rubber antioxidant 6PPD (also known as antioxidant 4020) is one of the high-performance, general-purpose antioxidants among amine antioxidants and is currently the most widely used environmentally friendly antioxidant globally. The production method of antioxidant 6PPD mainly involves the hydrogenation synthesis of p-aminodiphenylamine and methyl isobutyl ketone under the action of a catalyst. This method has a short process flow and readily available raw materials, making it the main method for industrial production of antioxidant 6PPD both domestically and internationally. However, during this hydrogenation process, some methyl isobutyl ketone (MIBK) is hydrogenated to methyl isobutyl methanol (MIBC). In the early stages, the byproduct rich in MIBC was sold at a low price as waste liquid, resulting in excessive raw material consumption. To further improve raw material utilization, reduce production costs, reduce waste, and enhance the competitiveness of existing products, the MIBC in the waste liquid is catalytically dehydrogenated in the gas phase to produce MIBK, which is then reused in the synthesis of antioxidant 6PPD. This method not only reduces the discharge of production waste liquid but also improves raw material utilization and reduces material consumption, resulting in significant economic benefits.

[0004]

[0005] Currently, the catalysts used in the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone are all copper-zinc-aluminum catalysts, which have small specific surface areas (all less than 75 m²). 2 / g), the active component has poor dispersibility, resulting in a low conversion rate of methyl isobutyl methanol.

[0006] For example, Zhejiang University disclosed a copper-based catalyst for the gas-phase catalytic dehydrogenation of methyl isobutyl alcohol and its preparation method in patent CN100486695C. This copper-zinc-aluminum catalyst is prepared by co-precipitation and calcination using 5-10 parts by weight of Cu(NO3)2·3H2O, 1-10 parts by weight of Zn(NO3)2·6H2O, 1-5 parts by weight of Al(NO3)3·9H2O, and 5-20 parts by weight of alkaline carbonate precipitant. When applied to the dehydrogenation of methyl isobutyl methanol to synthesize methyl isobutyl ketone, the maximum single-pass conversion rate is only 82%.

[0007] For example, the Nanjing Chemical Industry Group Research Institute disclosed a 4-methyl-2-pentanol dehydrogenation catalyst in patent CN104275186A. The mass percentages of CuO, ZnO, and Al2O3 in this catalyst are 20%–70%, 28%–70%, and 1%–10%, respectively. The copper-zinc-aluminum catalyst prepared by the co-precipitation method has a small specific surface area, all less than 75 m². 2 / g, the conversion rate of methyl isobutyl methanol is around 90%.

[0008] In summary, there is an urgent need to develop a novel dehydrogenation catalyst and preparation method for the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone, which can overcome the problems of poor catalyst activity and low conversion rate in existing technologies. Summary of the Invention

[0009] To overcome the shortcomings of existing technologies, such as poor catalyst activity and low conversion rates in the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone, this invention provides a dehydrogenation catalyst, its precursor, preparation method, application, and dehydrogenation reaction. The dehydrogenation catalyst provided by this invention has a large specific surface area, resulting in high dispersibility and excellent catalytic activity. When used to catalyze the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone, it can effectively improve the conversion rate and selectivity.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] This invention provides a method for preparing a dehydrogenation catalyst precursor, comprising the following steps:

[0012] S1: Add the precipitant solution to the mixed solution to carry out the precipitation reaction, age it, and obtain the slurry;

[0013] The mixed solution is a mixture of a metal salt solution and a silica gel solution, wherein the metal salt solution includes copper salt; the endpoint pH value of the precipitation reaction is in the range of 7 to 11.

[0014] S2: The slurry is post-processed to obtain the dehydrogenation catalyst precursor.

[0015] In this invention, the metal salt solution in step S1 refers to an aqueous solution of a soluble metal salt.

[0016] In step S1, the copper salt is a conventional soluble copper salt in the art, such as one or more of copper nitrate, copper sulfate, copper chloride and copper acetate. The copper nitrate in this invention is preferably in the form of copper nitrate trihydrate.

[0017] In step S1, the amount of copper salt added is preferably 10%-75%. This amount is calculated as the percentage of the mass of copper oxide (copper oxide) in the copper salt solution relative to the total mass of the metal oxide in the metal salt solution and the total mass of silica in the silica gel solution.

[0018] In step S1, the mass fraction of copper salt in the metal salt solution is preferably 8 wt% to 40 wt%, for example 12.4 wt%, 15.7 wt%, 16.7 wt%, 21.3 wt%, or 22.8 wt%.

[0019] In some preferred embodiments, in step S1, the metal salt solution further includes an auxiliary metal salt.

[0020] The auxiliary metal salt may be one or more of the nitrates, carbonates and sulfates of Na, K, Ca, Mg, Zn, In, Ce, Zr, Mg, Mo, Ni and Mn, preferably nitrates.

[0021] In some specific embodiments, the nitrate is preferably zinc nitrate hexahydrate, nickel nitrate hexahydrate, or zirconium nitrate pentahydrate.

[0022] The preferred amount of the additive metal salt is 0.01% to 6%. The addition amount is calculated as the mass percentage of the oxide of the additive metal in the metal salt solution to the total mass of silica in the silica gel solution, based on the oxide form of the additive metal.

[0023] The mass fraction of the auxiliary metal salt in the metal salt solution is preferably 0.01 wt% to 6 wt%, for example 0.12 wt%, 0.20 wt%, 0.30 wt%, 0.32 wt%, or 0.50 wt%.

[0024] In this invention, in step S1, the silica gel solution refers to a heterogeneous dispersion system formed by nano-sized silica particles in water. Silica gel solutions have a high specific surface area and controllable particle size distribution. Using silica gel solutions to prepare dehydrogenation catalysts is beneficial for increasing the specific surface area of ​​the dehydrogenation catalyst and the dispersibility of its active components, thereby increasing the number of active sites on the surface of the dehydrogenation catalyst and improving its activity.

[0025] In step S1, the amount of silica gel solution added is 25% to 90%. This amount is calculated as the percentage of the mass of silica in the silica gel solution relative to the mass of the metal oxide in the metal salt solution and the total mass of silica in the silica gel solution.

[0026] In step S1, the silica sol solution can be prepared using conventional methods in the art, and the raw materials for its preparation may include one or more of silica sol, fumed silica, methyl silicate, ethyl silicate and propyl silicate.

[0027] In some embodiments of the present invention, the raw material for preparing the silica gel solution is silica sol, and the silica gel solution can be obtained by mixing the silica sol with deionized water and then adding an acidic substance.

[0028] The mass fraction of SiO2 in the silica sol is preferably 20% to 40%, for example, 25%.

[0029] The acidic substance is a conventional soluble acid in the art, preferably one or more of nitric acid, sulfuric acid, acetic acid and hydrochloric acid, and the nitric acid in the present invention is preferably concentrated nitric acid.

[0030] In some embodiments of the present invention, the mass fraction of the concentrated nitric acid is preferably 65 wt% to 68 wt%.

[0031] The amount of concentrated nitric acid added depends on the pH value of the mixed solution of silica sol and deionized water, and the pH value is preferably 3 to 5.

[0032] In some embodiments of the present invention, the raw materials for preparing the silica gel solution are one or more selected from fumed silica, methyl silicate, ethyl silicate, and propyl silicate. The silica gel solution can be obtained by mixing one or more of the fumed silica, methyl silicate, ethyl silicate, and propyl silicate with deionized water. When methyl silicate, ethyl silicate, and propyl silicate are used to prepare the silica gel solution, the raw materials will gradually decompose into silica when mixed with water.

[0033] In step S1, the mass fraction of silica in the silica gel solution is preferably 5 wt% to 20 wt%, for example 5 wt%, 13.6 wt%, 14.2 wt%, 15.8 wt%, or 16.6 wt%.

[0034] In this invention, in step S1, the metal salt solution is mixed with the silica gel solution to obtain the mixed solution.

[0035] In this invention, in step S1, the precipitant in the precipitant solution is a conventional soluble alkaline substance in the art, such as one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, and potassium hydroxide, preferably sodium carbonate or potassium carbonate. The precipitant solution refers to an aqueous solution of the aforementioned conventionally used soluble alkaline substances as precipitants in the art.

[0036] In step S1, the mass fraction of the precipitant in the precipitant solution is preferably 10 wt% to 30 wt%, for example 10 wt%, 12 wt%, 15 wt%, 16.6 wt%, or 19.3 wt%.

[0037] In step S1, the precipitant solution is preferably added to the mixed solution over a period of 0.5 to 6 hours.

[0038] In step S1, in some specific implementations, the precipitant solution is added to the mixed solution by dripping.

[0039] This invention controls the dropping time of the above-mentioned precipitant solution within the range of 0.5 to 6 hours, so that the mixed solution system remains uniform throughout the reaction process, which is beneficial to improving repeatability.

[0040] In this invention, step S1 involves a precipitation reaction where the pH value increases from acidic to alkaline. The initial mixed solution is acidic; as the precipitant solution is gradually added, the pH value rises slowly. When the desired endpoint is reached, the addition of the precipitant solution is stopped. Therefore, controlling the precipitation reaction involves controlling the endpoint pH value. The endpoint pH value of the precipitation reaction determines the structure of the dehydrogenation catalyst. By controlling the endpoint pH value of the precipitation reaction to be alkaline, the acidic sites on the silica surface are neutralized, side reactions are reduced, and selectivity is improved.

[0041] In step S1, the endpoint pH value of the precipitation reaction is preferably 7 to 10, for example 7.5, 8.5 or 9.5.

[0042] In step S1, the temperature of the precipitation reaction is preferably 40°C to 80°C, for example 50°C or 60°C.

[0043] By setting the temperature of the precipitation reaction within the above-mentioned range, this invention can ensure a fast reaction rate and facilitate the control of actual industrial production, keeping the amount of water evaporation during the preparation process within a controllable range, and is highly operable.

[0044] In some preferred embodiments, step S2 includes aging, filtering, washing, drying, calcination, and shaping.

[0045] The aging temperature is preferably 40℃~80℃, for example 50℃ or 60℃.

[0046] The aging time is preferably 1 to 4 hours.

[0047] The filtering method described herein is a conventional filtering method in the art.

[0048] The washing method described herein is a conventional washing method in the art.

[0049] The drying temperature is preferably 80℃ to 150℃, for example 120℃.

[0050] The drying time is preferably 8 to 12 hours.

[0051] The roasting temperature is preferably 300℃ to 600℃, for example 400℃, 450℃, 500℃ or 550℃.

[0052] The roasting time is preferably 1 to 4 hours.

[0053] The molding method can be a conventional method in the art, such as tableting.

[0054] The present invention also provides a dehydrogenation catalyst precursor, which is prepared according to the above-described method for preparing a dehydrogenation catalyst precursor. The dehydrogenation catalyst precursor includes an active component precursor and a support, wherein the active component precursor includes copper oxide and the support is SiO2.

[0055] In this invention, the content of copper oxide is 10% to 75%, for example 23.8%, 29.4%, 40.6%, 55.2%, 55.3% or 60.2%, where the percentage is the mass percentage of copper oxide in the dehydrogenation catalyst precursor.

[0056] In this invention, the content of the support is 25% to 90%, for example 39.2%, 44.1%, 58.2%, 70.4%, 76.2% or 44.2%, where the percentage is the mass percentage of the support relative to the dehydrogenation catalyst precursor.

[0057] In this invention, the specific surface area of ​​the dehydrogenation catalyst precursor is preferably 160–600 m². 2 / g, for example 180m 2 / g, 278m 2 / g, 296m 2 / g, 316m 2 / g, 360m 2 / g or 405m 2 / g.

[0058] In this invention, the pore volume of the dehydrogenation catalyst precursor is preferably 0.3 cm. 3 / g~1.5cm 3 / g, for example 0.36cm 3 / g, 0.45cm 3 / g, 0.5cm 3 / g, 0.64cm 3 / g, 0.66cm 3 / g or 0.91cm 3 / g.

[0059] In some embodiments of the present invention, the active component precursor further includes an auxiliary oxide, which is one or more oxides of elements such as Na, K, Ca, Mg, Zn, In, Ce, Zr, Mg, Mo, Ni and Mn.

[0060] The content of the auxiliary oxide is preferably 0.01% to 6%, for example 0.2%, 0.5%, 0.6%, 0.7% or 1.2%, where the percentage is the mass percentage of the auxiliary oxide to the dehydrogenation catalyst precursor.

[0061] The present invention also provides a dehydrogenation catalyst precursor, which includes an active component precursor and a support, wherein the active component precursor includes copper oxide and the support is SiO2, wherein the content of copper oxide is 10% to 75% and the content of the support is 25% to 90%.

[0062] The present invention also provides a dehydrogenation catalyst, which is obtained by reduction of the above-mentioned dehydrogenation catalyst precursor. The dehydrogenation catalyst includes an active component and a support, wherein the active component includes copper and the support is SiO2.

[0063] In this invention, the copper content is 10% to 60%, where the percentage is the mass percentage of copper in the dehydrogenation catalyst.

[0064] In this invention, during the reduction process of the dehydrogenation catalyst precursor, copper oxide is reduced to copper; the silica support remains unchanged; when the dehydrogenation catalyst precursor also includes an auxiliary oxide, the auxiliary oxide will not be reduced.

[0065] In some embodiments of the present invention, the active component further includes an auxiliary oxide, which is one or more oxides of elements such as Na, K, Ca, Mg, Zn, In, Ce, Zr, Mg, Mo, Ni and Mn.

[0066] In this invention, the reduction time is preferably 1 to 72 hours, for example 4 hours, 24 hours or 36 hours.

[0067] In this invention, the reducing atmosphere can be hydrogen or a mixture of hydrogen and nitrogen.

[0068] In some embodiments of the present invention, the reducing atmosphere is a mixture of hydrogen and nitrogen, wherein the volume percentage of hydrogen is preferably 0.1% to 50%. In the actual operation of reduction using a mixed gas, the volume percentage of hydrogen in the mixed gas can be dynamically changed, that is, the volume percentage of hydrogen in the mixed gas can be gradually increased from a low concentration of 0.1% to a high concentration of 50%.

[0069] The present invention also provides a dehydrogenation catalyst, comprising an active component and a support, wherein the active component comprises copper, and the support is SiO2, wherein the content of copper is 10% to 60%, and the content of the support is 40% to 90%.

[0070] The present invention also provides a dehydrogenation reaction for preparing methyl isobutyl ketone, which uses the above-mentioned dehydrogenation catalyst to catalyze the dehydrogenation reaction of the reaction raw materials, wherein the reaction raw materials include methyl isobutyl methanol, the temperature of the dehydrogenation reaction is 160℃~260℃, and the pressure of the dehydrogenation reaction is 0~0.5MPa.

[0071] The present invention also provides the application of the above-mentioned dehydrogenation catalyst in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, wherein the reaction raw material for the dehydrogenation reaction includes methyl isobutyl methanol, the temperature of the dehydrogenation reaction is 160℃~260℃, and the pressure of the dehydrogenation reaction is 0~0.5MPa.

[0072] In this invention, the dehydrogenation reaction is preferably a gas-phase dehydrogenation reaction.

[0073] In this invention, the liquid hourly space velocity (LHSV) of the dehydrogenation reaction can be 0.2–4.0 h⁻¹. -1 Preferably 0.5–2.0 h -1 For example, 0.6h -1 1.0h -1 Or 1.5h -1 .

[0074] In the dehydrogenation reaction using the dehydrogenation catalyst described in this invention, a suitable dehydrogenation reaction temperature is crucial. This invention, by controlling the dehydrogenation reaction temperature within the aforementioned range, not only improves the conversion rate of methyl isobutyl methanol and ensures the long-term activity of the dehydrogenation catalyst, but also controls the occurrence of side reactions, ensuring the selectivity of methyl isobutyl ketone. The preferred temperature for the dehydrogenation reaction is 210℃ to 250℃, for example, 230℃.

[0075] In the above-described dehydrogenation reaction using the dehydrogenation catalyst described in this invention, a suitable dehydrogenation reaction pressure is also crucial. This invention ensures a high conversion rate of methyl isobutyl methanol by controlling the dehydrogenation reaction pressure within the aforementioned range. The dehydrogenation reaction pressure is, for example, 0.1 MPa, i.e., atmospheric pressure.

[0076] In some specific implementations, the dehydrogenation reaction includes the following steps:

[0077] (1) The dehydrogenation catalyst precursor is loaded into a fixed-bed reactor and reduced under a reducing atmosphere to obtain the dehydrogenation catalyst;

[0078] (2) Using an inert gas as a carrier gas, the reactants are introduced into a fixed-bed reactor to react and obtain the product; wherein, the reactants include methyl isobutyl methanol;

[0079] (3) The product is condensed and separated into gas and liquid to obtain methyl isobutyl ketone.

[0080] In step (1), the fixed-bed reactor is, for example, a tubular fixed-bed reactor, an axially adiabatic fixed-bed reactor, or a radially adiabatic fixed-bed reactor, preferably a tubular fixed-bed reactor. In step (2), the reaction feedstock can be methyl isobutyl methanol.

[0081] In step (2), the inert gas refers to a protective gas that does not participate in the reaction, and does not specifically refer to the rare gases corresponding to group 0 elements. The inert gas mentioned in this invention is, for example, one or more of argon, helium, and nitrogen, preferably nitrogen.

[0082] In step (3), the condensation is a conventional condensation method in the art.

[0083] In step (3), the gas-liquid separation is a conventional method in the art, such as gas-liquid separation in a separator.

[0084] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0085] The reagents and raw materials used in this invention are all commercially available.

[0086] The positive and progressive effects of this invention are as follows:

[0087] 1. The dehydrogenation catalyst precursor prepared by the method of the present invention, after reduction, can effectively avoid the occurrence of side reactions such as secondary alcohol dehydration and ketone condensation to higher ketones in the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone, and significantly improve the selectivity of methyl isobutyl ketone to more than 95%, or even more than 99%.

[0088] 2. The specific surface area of ​​the dehydrogenation catalyst prepared by this invention is more than twice that of conventional copper-zinc-aluminum catalysts, which can effectively improve the dispersibility and activity of the dehydrogenation catalyst. When the dehydrogenation catalyst prepared by this invention is used to catalyze the gas-phase dehydrogenation reaction of methyl isobutyl methanol to methyl isobutyl ketone, the conversion rate of methyl isobutyl methanol can be significantly improved, with a conversion rate of more than 95%, and even more than 99%. Detailed Implementation

[0089] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0090] Copper nitrate trihydrate (CAS: 10031-43-3)

[0091] Calcium nitrate tetrahydrate (CAS: 13477-34-4)

[0092] Zinc nitrate hexahydrate (CAS: 10196-18-6)

[0093] Nickel nitrate hexahydrate (CAS: 13478-00-7)

[0094] Zirconium nitrate pentahydrate (CAS: 13986-27-1)

[0095] Magnesium nitrate hexahydrate (CAS: 13446-18-9)

[0096] Sodium carbonate (CAS: 497-19-8)

[0097] Nitric acid (CAS: 7697-37-2)

[0098] Example 1

[0099] 1. Preparation of dehydrogenation catalyst precursors

[0100] (1) Place 95g of copper nitrate trihydrate and 1g of calcium nitrate tetrahydrate in a beaker, add 500g of deionized water to dissolve them completely, and the resulting metal salt solution (the mass fraction of copper salt is 12.4wt%, and the mass fraction of auxiliary metal salt is 0.12wt%) is denoted as solution 1.

[0101] (2) Weigh 300g of silica sol (SiO2 mass fraction of 25%), add 150g of deionized water and stir evenly. Then, slowly add concentrated nitric acid (add concentrated nitric acid with a mass fraction of 65wt% to 68wt% until the pH value is 3.5) with a dropper. The resulting silica sol solution (silica mass fraction of 16.6wt%) is recorded as solution 2.

[0102] (3) Weigh 100g of sodium carbonate, add 900g of deionized water to dissolve it, and the resulting precipitant solution (the mass fraction of the precipitant is 10wt%) is denoted as solution 3.

[0103] (4) Add precipitant solution 3 dropwise into the mixture of solution 1 and solution 2 at a time of 1 hour. Carry out the precipitation reaction at a temperature of 50°C. Terminate the reaction when the pH rises to 8.5. Then raise the temperature to 70°C and start aging for 4 hours.

[0104] (5) After aging, the slurry is filtered and washed. The obtained solid material is dried at 100°C for 12 hours, then roasted in a roasting furnace at 400°C for 4 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0105] The obtained dehydrogenation catalyst precursor contains approximately 29.4% copper oxide, approximately 70.4% SiO2 support, and approximately 0.2% auxiliary oxide.

[0106] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 360 m². 2 / g, pore volume 0.64cm 3 / g, see Table 1 for details.

[0107] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0108] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced in a hydrogen atmosphere; wherein the reduction temperature is 210℃ and the reduction time is 4h to obtain the dehydrogenation catalyst.

[0109] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the mixture was subjected to a liquid hourly space velocity of 0.6 h⁻¹ under normal pressure, at 210 °C. -1 The reaction is carried out under certain conditions to obtain the product.

[0110] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0111] The conversion rate of methyl isobutyl methanol and the selectivity of methyl isobutyl ketone are detailed in Table 1, where:

[0112] The formula for the conversion rate of methyl isobutyl methanol is:

[0113]

[0114] The formula for calculating the selectivity of methyl isobutyl ketone is:

[0115]

[0116] Example 2

[0117] 1. Preparation of dehydrogenation catalyst precursors

[0118] (1) Place 138g of copper nitrate trihydrate and 5g of zinc nitrate hexahydrate in a beaker, add 500g of deionized water to dissolve them completely, and the resulting metal salt solution (the mass fraction of copper salt is 16.7wt%, and the mass fraction of auxiliary metal salt is 0.50wt%) is denoted as solution 1.

[0119] (2) Weigh 260g of silica sol (SiO2 mass fraction of 25%), add 150g of deionized water and stir evenly. Then, slowly add concentrated nitric acid (add concentrated nitric acid with a mass fraction of 65wt% to 68wt% until the pH value is 3.5) using a dropper. The resulting silica sol solution (silica mass fraction of 15.8wt%) is recorded as solution 2.

[0120] (3) Weigh 150g of sodium carbonate, add 850g of deionized water to dissolve it, and the resulting precipitant solution (precipitant mass fraction 15wt%) is recorded as solution 3.

[0121] (4) Add precipitant solution 3 dropwise into the mixture of solution 1 and solution 2 at a time of 4h. Carry out the precipitation reaction at a temperature of 60℃. Terminate the reaction when the pH rises to 8.5 and maintain the temperature at 60℃ for 4 hours.

[0122] (5) After aging, the slurry is filtered and washed. The obtained solid material is dried at 120°C for 8 hours, then roasted in a roasting furnace at 450°C for 2 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0123] The prepared dehydrogenation catalyst precursor contained approximately 40.6% copper oxide, approximately 58.2% SiO2 support, and approximately 1.2% auxiliary oxide.

[0124] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 405 m². 2 / g, pore volume is 0.91cm 3 / g, see Table 1 for details.

[0125] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0126] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced in a hydrogen atmosphere; wherein the reduction temperature is 230°C and the reduction time is 4h to obtain the dehydrogenation catalyst.

[0127] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the mixture was subjected to a liquid hourly space velocity of 0.6 h⁻¹ under normal pressure, at 230 °C. -1 The reaction is carried out under certain conditions to obtain the product.

[0128] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0129] Example 3

[0130] 1. Preparation of dehydrogenation catalyst precursors

[0131] (1) Place 210g of copper nitrate trihydrate and 4g of magnesium nitrate hexahydrate in a beaker, add 500g of deionized water to dissolve them completely, and the resulting metal salt solution (the mass fraction of copper salt is 22.8wt%, and the mass fraction of auxiliary metal salt is 0.32wt%) is denoted as solution 1.

[0132] (2) Weigh 180g of silica sol (SiO2 mass fraction of 25%), add 150g of deionized water and stir evenly. Then, slowly add concentrated nitric acid (add concentrated nitric acid with a mass fraction of 65wt% to 68wt% until the pH value is 3.5) using a dropper. The resulting silica sol solution (silica mass fraction of 13.6wt%) is recorded as solution 2.

[0133] (3) Weigh 240g of potassium carbonate, add 1000g of deionized water to dissolve it, and the resulting precipitant solution (precipitant mass fraction 19.3wt%) is recorded as solution 3.

[0134] (4) The precipitant solution was added dropwise to the mixture of solution 1 and solution 2 at a time of 1 hour. The precipitation reaction was carried out at a temperature of 40°C. The reaction was terminated when the pH rose to 7.5. The mixture was then aged at 40°C for 2 hours.

[0135] (5) After aging, the slurry is filtered and washed. The obtained solid material is dried at 120°C for 8 hours, then roasted in a roasting furnace at 450°C for 2 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0136] The obtained dehydrogenation catalyst precursor contains approximately 60.2% copper oxide, approximately 39.2% SiO2 support, and approximately 0.6% auxiliary oxide.

[0137] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 278 m². 2 / g, pore volume is 0.36cm 3 / g, see Table 1 for details.

[0138] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0139] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced in a hydrogen atmosphere; wherein the reduction temperature is 230°C and the reduction time is 4h to obtain the dehydrogenation catalyst.

[0140] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the mixture was subjected to atmospheric pressure, 230°C, and a liquid hourly space velocity of 1 h⁻¹. -1 The reaction is carried out under certain conditions to obtain the product.

[0141] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0142] Example 4

[0143] 1. Preparation of dehydrogenation catalyst precursors

[0144] (1) Place 76g of copper nitrate trihydrate in a beaker, add 300g of deionized water to dissolve it completely, and the resulting metal salt solution (metal salt mass fraction 15.7wt%) is denoted as solution 1.

[0145] (2) Weigh 80g of fumed silica, add 1600g of deionized water and stir until homogeneous. The resulting silica gel solution (silica mass fraction 5wt%) is denoted as solution 2.

[0146] (3) Weigh 120g of sodium carbonate, add 880g of deionized water to dissolve it, and the resulting precipitant solution (precipitant mass fraction 12wt%) is recorded as solution 3.

[0147] (4) Add the precipitant solution 3 dropwise to the mixture of solution 1 and solution 2 at a time of 1 hour. Carry out the precipitation reaction at a temperature of 50°C. Terminate the reaction when the pH rises to 9.5 and maintain the temperature at 50°C for 2 hours.

[0148] (5) After aging, the slurry is filtered and washed. The obtained solid material is dried at 120°C for 8 hours, then roasted in a roasting furnace at 500°C for 2 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0149] The obtained dehydrogenation catalyst precursor contained approximately 23.8% copper oxide and approximately 76.2% SiO2 support.

[0150] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 180 m². 2 / g, pore volume 0.5cm 3 / g, see Table 1 for details.

[0151] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0152] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced in a hydrogen atmosphere; wherein the reduction temperature is 230°C and the reduction time is 4h to obtain the dehydrogenation catalyst.

[0153] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the mixture was subjected to a liquid hourly space velocity of 1.5 h⁻¹ under normal pressure, at 250 °C. -1 The reaction is carried out under certain conditions to obtain the product.

[0154] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0155] Example 5

[0156] 1. Preparation of dehydrogenation catalyst precursors

[0157] (1) Place 190g of copper nitrate trihydrate, 2g of nickel nitrate hexahydrate and 1.5g of magnesium nitrate hexahydrate in a beaker, add 500g of deionized water to dissolve them completely, and the resulting metal salt solution (the mass fraction of copper salt is 21.3wt% and the mass fraction of auxiliary metal salt is 0.30wt%) is denoted as solution 1.

[0158] (2) Weigh 168g of silica sol (SiO2 mass fraction of 30%), add 150g of deionized water and stir evenly. Then, slowly add concentrated nitric acid (add concentrated nitric acid with a mass fraction of 65wt% to 68wt% until the pH value is 3.5) using a dropper. The resulting silica sol solution (silica mass fraction of 15.8wt%) is recorded as solution 2.

[0159] (3) Weigh 200g of sodium carbonate, add 1000g of deionized water to dissolve it, and the resulting precipitant solution (precipitant mass fraction 16.6wt%) is denoted as solution 3.

[0160] (4) Add the precipitant solution 3 dropwise into the mixture of solution 1 and solution 2 at a time of 2 hours. Carry out the precipitation reaction at a temperature of 40°C. Terminate the reaction when the pH rises to 9.5. Then raise the temperature to 70°C and age for 2 hours.

[0161] (5) After aging, the slurry is filtered and washed. The obtained solid material is dried at 120°C for 12 hours, then roasted in a roasting furnace at 550°C for 2 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0162] The prepared dehydrogenation catalyst precursor contained approximately 55.2% copper oxide, approximately 44.1% SiO2 support, and approximately 0.7% auxiliary oxide.

[0163] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 296 m². 2 / g, pore volume 0.66cm 3 / g, see Table 1 for details.

[0164] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0165] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced in a hydrogen atmosphere; wherein the reduction temperature is 230°C and the reduction time is 4h to obtain the dehydrogenation catalyst.

[0166] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the mixture was subjected to a liquid hourly space velocity of 0.6 h⁻¹ under normal pressure, at 230 °C.-1 The reaction is carried out under certain conditions to obtain the product.

[0167] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0168] Example 6

[0169] 1. Preparation of dehydrogenation catalyst precursors

[0170] (1) Weigh 190g of copper nitrate trihydrate and 1.8g of zirconium nitrate hexahydrate into a beaker, add 500g of deionized water to dissolve them completely, and the resulting metal salt solution (the mass fraction of copper salt is 21.3wt%, and the mass fraction of auxiliary metal salt is 0.2wt%) is denoted as solution 1.

[0171] (2) Weigh 200g of silica sol (SiO2 mass fraction of 25%), add 150g of deionized water and stir evenly. Then, slowly add concentrated nitric acid (add concentrated nitric acid with a mass fraction of 65wt% to 68wt% until the pH value is 3.5) with a dropper. The resulting silica sol solution (silica mass fraction of 14.2wt%) is recorded as solution 2.

[0172] (3) Weigh 200g of sodium carbonate, add 1000g of deionized water to dissolve it, and the resulting precipitant solution (precipitant mass fraction 16.7wt%) is denoted as solution 3.

[0173] (4) Add precipitant solution 3 dropwise into the mixture of solution 1 and solution 2 at a time of 1 hour. Carry out the precipitation reaction at a temperature of 60°C. Terminate the reaction when the pH rises to 10. Then, heat the mixture to 60°C and age it for 3 hours.

[0174] (5) After aging, the slurry is filtered and washed. The obtained solid material is dried at 90°C for 12 hours, then roasted in a roasting furnace at 550°C for 2 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0175] The prepared dehydrogenation catalyst precursor contained approximately 55.3% copper oxide, approximately 44.2% SiO2 support, and approximately 0.5% auxiliary oxide.

[0176] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 316 m². 2 / g, pore volume 0.45cm 3 / g, see Table 1 for details.

[0177] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0178] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced in a hydrogen atmosphere; wherein the reduction temperature is 230°C and the reduction time is 4h to obtain the dehydrogenation catalyst.

[0179] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the mixture was subjected to atmospheric pressure, 230°C, and a liquid hourly space velocity of 2 h⁻¹. -1 The reaction is carried out under certain conditions to obtain the product.

[0180] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0181] Comparative Example 1

[0182] 1. Preparation of dehydrogenation catalyst precursors

[0183] (1) Place 82g of copper nitrate trihydrate, 102g of zinc nitrate hexahydrate and 52g of aluminum nitrate nonahydrate in a beaker, add 1000g of deionized water to dissolve them completely, and the resulting metal salt solution is called solution 1.

[0184] (2) Weigh 100g of sodium carbonate and dissolve it in 900g of deionized water. This solution is called solution 2.

[0185] (3) Add precipitant solution 2 to solution 1 and carry out precipitation reaction at 50°C. Stop the reaction when the pH rises to 8.5 and then heat to 50°C for 3 hours.

[0186] (4) After aging, the slurry is filtered and washed. The obtained solid material is dried at 120°C for 8 hours, then roasted in a roasting furnace at 450°C for 2 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0187] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 68 m². 2 / g, pore volume 0.25cm 3 / g, see Table 1 for details.

[0188] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0189] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced under a mixed gas of hydrogen and nitrogen; wherein the reduction temperature is 230°C and the reduction time is 4h, and the dehydrogenation catalyst is obtained.

[0190] (2) The product was obtained by reacting methyl isobutyl methanol as raw material and nitrogen as carrier gas under normal pressure, 230°C and liquid hourly space velocity of 0.6 h-1.

[0191] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0192] Comparative Example 2

[0193] 1. Preparation of dehydrogenation catalyst precursors

[0194] (1) Place 138g of copper nitrate trihydrate and 5g of zinc nitrate in a beaker, add 500g of deionized water to dissolve them completely, and the resulting metal salt solution is denoted as solution 1.

[0195] (2) Weigh 260g of silica sol (SiO2 mass fraction of 25%), add 150g of deionized water and stir evenly. Then, slowly add concentrated nitric acid (add concentrated nitric acid with a mass fraction of 65wt% to 68wt% until the pH value is 3.5) using a dropper. The resulting silica sol solution (silica mass fraction of 15.8wt%) is recorded as solution 2.

[0196] (3) Weigh 150g of sodium carbonate, add 850g of deionized water to dissolve it, and the resulting precipitant solution (precipitant mass fraction 15wt%) is recorded as solution 3.

[0197] (4) Add precipitant solution 3 dropwise into the mixture of solution 1 and solution 2 at a time of about 1 hour. Carry out the precipitation reaction at a temperature of 60°C. Terminate the reaction when the pH rises to 6.5 and maintain the temperature at 60°C for 4 hours.

[0198] (5) After aging, the slurry is filtered and washed. The obtained solid material is dried at 120°C for 8 hours, then roasted in a roasting furnace at 450°C for 2 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0199] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 372 m². 2 / g, pore volume 0.48cm 3 / g, see Table 1 for details.

[0200] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0201] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced under a mixed gas of hydrogen and nitrogen; wherein the reduction temperature is 230°C and the reduction time is 4h, and the dehydrogenation catalyst is obtained.

[0202] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the mixture was subjected to a liquid hourly space velocity of 0.6 h⁻¹ under normal pressure, at 230 °C. -1 The reaction is carried out under certain conditions to obtain the product.

[0203] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0204] Comparative Example 3

[0205] 1. Preparation of dehydrogenation catalyst precursors

[0206] The preparation method of the dehydrogenation catalyst precursor is the same as in Example 5.

[0207] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0208] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced in a hydrogen atmosphere; wherein the reduction temperature is 230°C and the reduction time is 4h to obtain the dehydrogenation catalyst.

[0209] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the time space velocity was 0.6 h⁻¹ at 0.5 MPa, 300 °C, and a raw material mass liquid hourly space velocity of 0.6 h⁻¹. -1 The reaction is carried out under certain conditions to obtain the product.

[0210] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0211] Comparative Example 4

[0212] 1. Preparation of dehydrogenation catalyst precursors

[0213] The preparation method of the dehydrogenation catalyst precursor is the same as in Example 5.

[0214] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0215] (1) The dehydrogenation catalyst precursor is loaded into the fixed bed reactor and activated and reduced in a hydrogen atmosphere; wherein the reduction temperature is 230°C and the reduction time is 4h to obtain the dehydrogenation catalyst.

[0216] (2) Using methyl isobutyl methanol as raw material and nitrogen as carrier gas, the mixture was subjected to a flow rate of 0.8 MPa, 230 °C, and a raw material mass liquid hourly space velocity of 0.6 h⁻¹. -1 The reaction is carried out under certain conditions to obtain the product.

[0217] (3) The product is condensed and separated into gas and liquid in a separator to obtain methyl isobutyl ketone.

[0218] Comparative Example 5

[0219] 1. Preparation of dehydrogenation catalyst precursors

[0220] (1) Place 190g of copper nitrate trihydrate, 2g of nickel nitrate hexahydrate and 1.5g of magnesium nitrate hexahydrate in a beaker, add 500g of deionized water to dissolve them completely, and the resulting metal salt solution is called solution 1.

[0221] (2) Weigh 240g of sodium silicate nonahydrate, add 370g of deionized water and stir well. Then slowly add concentrated nitric acid with a dropper and record it as solution 2.

[0222] (3) Weigh 200g of sodium carbonate, add 1000g of deionized water to dissolve it, and the resulting precipitant solution (precipitant mass fraction 20wt%) is denoted as solution 3.

[0223] (4) Add precipitant solution 3 to the mixture of solution 1 and solution 2, carry out the precipitation reaction at 40°C, stop the reaction when the pH rises to 9.5, and then heat to 70°C for 2 hours to age.

[0224] (5) After aging, the slurry is filtered and washed. The obtained solid material is dried at 120°C for 12 hours, then roasted in a roasting furnace at 550°C for 2 hours, pressed into tablets and crushed into particles of 20-40 mesh to obtain the dehydrogenation catalyst precursor.

[0225] The specific surface area of ​​the prepared dehydrogenation catalyst precursor is 148 m². 2 / g, pore volume 0.35cm 3 / g, see Table 1 for details.

[0226] 2. Preparation of methyl isobutyl ketone by dehydrogenation of methyl isobutyl methanol

[0227] The preparation method of methyl isobutyl ketone is the same as in Example 2.

[0228] Table 1

[0229]

[0230]

[0231] As shown in Table 1:

[0232] (1) The dehydrogenation catalyst precursors prepared in Examples 1-6 all have large specific surface areas, and their specific surface areas are all greater than 180 m². 2 / g, and can even exceed 400m 2 / g; The dehydrogenation catalysts prepared in Examples 1 to 6 were used to catalyze the gas-phase dehydrogenation reaction of methyl isobutyl methanol to methyl isobutyl ketone. The conversion rate of methyl isobutyl methanol can reach more than 95%, or even more than 99%, and the selectivity of methyl isobutyl ketone can reach more than 95%, or even more than 99%.

[0233] (2) Comparative Example 1 used a conventional copper-zinc-aluminum catalyst, which significantly reduced the specific surface area, and the conversion rate of methyl isobutyl methanol was reduced to 86.5%, and the selectivity of methyl isobutyl ketone was reduced to 90.8%.

[0234] (3) Comparative Example 2 is a catalyst obtained by precipitation under acidic conditions. The conversion rate of methyl isobutyl methanol is slightly reduced, and the selectivity of methyl isobutyl ketone is significantly reduced. This is because the preparation of the catalyst under alkaline conditions in this invention neutralizes the acidic sites on the surface, avoiding side reactions such as dehydration of secondary alcohols and ketone condensation into higher ketones, thereby effectively improving the selectivity of methyl isobutyl ketone.

[0235] (4) The reaction temperature of Comparative Example 3 is higher than the range of protection of this application. Although high temperature is beneficial to improving the conversion rate of methyl isobutyl methanol, it is also beneficial to the side reaction, resulting in a significant decrease in the selectivity of methyl isobutyl ketone to 66.2%.

[0236] (5) In Comparative Example 4, the conversion rate of methyl isobutyl methanol decreased significantly to 60.4% when reacted at 0.8 MPa. This is because the reaction of methyl isobutyl methanol dehydrogenation to methyl isobutyl ketone is a reaction with increased volume, which increases the reaction pressure and thus inhibits the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone.

[0237] (6) Comparative Example 5 used soluble silicate to prepare SiO2 support, and the specific surface area of ​​the resulting catalyst was only 148 m². 2 / g, the conversion rate of methyl isobutyl methanol decreased to 88.2%, and the selectivity of methyl isobutyl ketone was only 92.4%.

Claims

1. The application of a dehydrogenation catalyst in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The method for preparing the precursor of the dehydrogenation catalyst includes the following steps: S1: Add the precipitant solution to the mixed solution to carry out the precipitation reaction and obtain the slurry; The mixed solution is a mixture of a metal salt solution and a silica gel solution, wherein the metal salt solution includes copper salt; the endpoint pH value of the precipitation reaction is in the range of 7 to 11. S2: The slurry is post-processed to obtain the precursor of the dehydrogenation catalyst; In step S1, the amount of copper salt added is 10% to 75%; wherein, the method for calculating the amount of copper salt is based on the mass percentage of copper oxide in the copper salt solution as a percentage of the mass of the metal oxide in the metal salt solution and the total mass of silica in the silica gel solution. In step S1, the metal salt solution further includes an auxiliary metal salt; In step S1, the auxiliary metal salt is one or more of the nitrates of Ca, Mg, Zn, Zr and Ni elements; In step S1, the amount of the auxiliary metal salt added is 0.01% to 6%; wherein, the method for calculating the amount of the addition is based on the mass percentage of the mass of the auxiliary metal oxide in the form of the auxiliary metal oxide in the auxiliary metal salt solution and the total mass of silica in the silica gel solution. In step S2, the post-processing includes aging, filtration, washing, drying, calcination, and molding; The dehydrogenation catalyst is obtained by reducing the precursor of the dehydrogenation catalyst. The dehydrogenation catalyst includes an active component and a support, wherein the active component includes copper and the support is SiO2.

2. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the copper salt is one or more of copper nitrate, copper sulfate, copper chloride, and copper acetate.

3. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the mass fraction of copper salt in the metal salt solution is 8wt% to 40wt%.

4. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the copper salt is copper nitrate.

5. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the raw materials for preparing the silica sol are one or more of silica sol, fumed silica, methyl silicate, ethyl silicate, and propyl silicate.

6. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the mass fraction of silica in the silica gel solution is 5wt%~20wt%.

7. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the precipitant in the precipitant solution is one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, and potassium hydroxide.

8. The application of the dehydrogenation catalyst according to claim 7 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the precipitant in the precipitant solution is sodium carbonate or potassium carbonate.

9. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the mass fraction of the precipitant in the precipitant solution is 10wt%~30wt%.

10. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The auxiliary metal salt mentioned in step S1 is a nitrate.

11. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the precipitant solution is added to the mixed solution dropwise during the precipitation reaction.

12. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the precipitant solution is added to the mixed solution over a period of 0.5 to 6 hours.

13. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the final pH value of the precipitation reaction is 7 to 10.

14. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In step S1, the temperature of the precipitation reaction is 40℃~80℃.

15. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, It meets one or more of the following conditions: (1) The aging temperature is 40℃~80℃; (2) The aging time is 1h~4h; (3) The drying temperature is 80℃~150℃; (4) The drying time is 8h~12h; (5) The roasting temperature is 300℃~600℃; (6) The roasting time is 1h~4h; (7) The molding method is tablet molding.

16. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The specific surface area of ​​the precursor for the dehydrogenation catalyst is 160–600 m². 2 / g.

17. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The pore volume of the precursor for the dehydrogenation catalyst is 0.3 cm³ / g to 1.5 cm³ / g.

18. The application of the dehydrogenation catalyst according to claim 17 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The reduction time is 1 to 72 hours.

19. The application of the dehydrogenation catalyst according to claim 17 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The reducing atmosphere is hydrogen or a mixture of hydrogen and nitrogen.

20. The application of the dehydrogenation catalyst according to claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, wherein, The reactants for the dehydrogenation reaction include methyl isobutyl methanol, the temperature of the dehydrogenation reaction is 160℃~260℃, and the pressure of the dehydrogenation reaction is 0~0.5MPa.

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