Dehydrogenation catalysts and precursors thereof, methods of making and use

Abstract

The application discloses a dehydrogenation catalyst and a precursor, a preparation method and application thereof. The dehydrogenation catalyst precursor is obtained through the following steps: mixing an aqueous solution of a precipitant and an aqueous solution of a metal salt to perform a precipitation reaction; and then performing post-treatment. The aqueous solution of the metal salt comprises a copper salt and a carrier alkaline earth metal salt. The temperature of the precipitation reaction is 30-90 DEG C. The end point pH value of the precipitation reaction is 6.0-10.0. The dehydrogenation catalyst precursor comprises an active component precursor and a carrier. The active component precursor is copper oxide. The carrier is one or more of alkaline earth metal oxides. The content of the copper oxide is 10%-75%. The content of the carrier is 5%-51%. The NH3 adsorption amount of the dehydrogenation catalyst precursor is less than 90 umol / g. The dehydrogenation catalyst obtained by reducing the dehydrogenation catalyst precursor is applied to a dehydrogenation reaction for preparing methyl isobutyl ketone. The temperature of the dehydrogenation reaction is 200-300 DEG C. The pressure of the dehydrogenation reaction is 0-0.5 MPa, and the dehydrogenation catalyst has high conversion rate and selectivity.

Description

Technical Field

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

[0002] Methyl isobutyl ketone (MIBK) is an excellent chemical intermediate and medium-boiling organic solvent. It is mainly used as a raw material for the production of rubber antioxidants, a dewaxing agent for lubricating oils, a flotation agent for mining, an extractant for organic synthesis, and a diluent, as well as a high-grade coating solvent for automobiles, aerospace, and home decoration.

[0003] Currently, the industrial production methods for methyl isobutyl ketone (MIBK) are mainly categorized by raw materials into the isopropanol route and the acetone route. Isopropanol-based MIBK production units can simultaneously produce polyketones, namely methyl isobutyl ketone, diisobutyl ketone, and acetone. Previously, since acetone was primarily produced via isopropanol dehydrogenation, the isopropanol method was the preferred industrial route for MIBK production. However, with the large-scale construction of phenol-ketone plants, acetone supply is abundant, and its cost is significantly lower than the isopropanol method. Therefore, the isopropanol-based MIBK synthesis process has gradually been replaced by the acetone method. Regarding the acetone raw material route, there are three-step and one-step methods. The three-step acetone method has been industrialized for many years, and companies such as Dow Chemical in the United States and Mitsui Chemicals in Japan still use this process to produce MIBK. Due to the rapid development of multifunctional catalysts, the one-step acetone method has been industrialized in Japan and Germany. This process has advantages such as a short process flow, low investment, high acetone conversion rate, high selectivity for MIBK, and low raw material and energy consumption, making it the most competitive and promising method. Currently, all domestic methyl isobutyl ketone (MOH) manufacturers use the one-step acetone production method.

[0004] Rubber antioxidant 6PPD is currently the most widely used environmentally friendly antioxidant globally. The main production method for 6PPD involves the hydrogenation synthesis of p-aminodiphenylamine and methyl isobutyl ketone (MIBK) under catalysis. However, during this hydrogenation process, some MIBK is hydrogenated to form methyl isobutyl methanol (MIBC). To further improve raw material utilization, reduce production costs, minimize waste, and enhance the competitiveness of existing products, the MIBC in the waste liquid is gas-phase catalytically dehydrogenated to produce MIBK, which is then reused in the synthesis of antioxidant 6PPD. This not only reduces wastewater discharge but also improves raw material utilization and reduces material consumption, resulting in significant economic benefits.

[0005] Extensive research has been conducted both domestically and internationally on the dehydrogenation of secondary alcohols, with numerous reports on dehydrogenation reactions of cyclohexanol, isopropanol, 2-butanol, and cyclopentanol. Regarding catalyst systems for the dehydrogenation of secondary alcohols to ketones, although various catalysts are used, copper-based catalysts are predominant, including copper-zinc, copper-aluminum, and copper-silicon catalysts. However, research on the dehydrogenation of methyl isobutyl methanol to prepare methyl isobutyl ketones is relatively limited.

[0006] Chinese invention patent CN100486695C discloses for the first time in China a CuO / ZnO / Al2O3 catalyst for the gas-phase catalytic dehydrogenation of methyl isobutyl alcohol to methyl isobutyl ketone. This copper-zinc-aluminum dehydrogenation catalyst is prepared by co-precipitation and calcination using a mixed salt solution of Cu(NO3)2, Zn(NO3)2, and Al(NO3)3. The prepared copper-based catalyst, when applied to the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone, achieves a single-pass conversion rate of 60%–82% and a selectivity of 96%–99%. However, its low single-pass conversion rate does not meet the requirements for industrial applications. To obtain a higher conversion rate, this patent employs a multi-pass cyclic reaction, but this method not only increases energy consumption but also hinders production efficiency.

[0007] Nanjing Chemical Industry Group Research Institute disclosed a copper-zinc-aluminum catalyst for the dehydrogenation of 4-methyl-2-pentanol in patent CN104275186A. This catalyst was prepared by a co-precipitation method, with the mass percentages of CuO, ZnO, and Al2O3 being 20%–70%, 28%–70%, and 1%–10%, respectively. When this catalyst was used for the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone, the highest selectivity was 93.3% when the conversion of methyl isobutyl methanol was greater than 95%; however, when the selectivity of methyl isobutyl ketone was greater than 99%, the conversion rates were all below 90%. It is difficult for the catalyst obtained by this method to simultaneously achieve an activity of greater than 95% conversion of methyl isobutyl methanol and greater than 99% selectivity of methyl isobutyl ketone.

[0008] In their paper "Study on the Process and Kinetics of Gas-Phase Catalytic Dehydrogenation of MIBC to MIBK," Zhejiang University suggests that the main reaction for the gas-phase dehydrogenation of methyl isobutyl methanol to synthesize methyl isobutyl ketone is endothermic, thus high-temperature conditions are beneficial for improving its conversion rate. Since the equilibrium conversion rate is low at low temperatures, high-temperature conditions are necessary to achieve a high conversion rate. However, high-temperature conditions also increase side reactions, leading to a decrease in the selectivity of the target product. Summary of the Invention

[0009] To address the shortcomings of existing copper-zinc-aluminum dehydrogenation catalysts used in the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone (MEK), which employ alumina as a support and exhibit poor selectivity for the target product, this invention provides a dehydrogenation catalyst, its precursor, preparation method, and application. The dehydrogenation catalyst described in this invention is applied to the dehydrogenation reaction of methyl isobutyl methanol to MEK. This catalyst exhibits excellent performance and can significantly improve the selectivity of MEK and the conversion rate of methyl isobutyl methanol.

[0010] The present invention solves the above-mentioned technical problems by adopting the following technical solutions:

[0011] This invention provides a dehydrogenation catalyst precursor, comprising an active component precursor and a support; wherein the active component precursor comprises copper oxide; the support comprises one or more alkaline earth metal oxides; the content of copper oxide is 10%-75%; the content of the support is 5%-51%; wherein the percentages are the percentages of the mass of each component to the total mass of the dehydrogenation catalyst precursor; and the NH3 adsorption capacity of the dehydrogenation catalyst precursor is less than 90 μmol / g.

[0012] In this invention, the copper oxide content is preferably 30%-70%, for example 39.5%, 42.3%, 44.5%, 44.7%, 46.9%, 49.4% or 63.8%.

[0013] In this invention, the content of the carrier is preferably 5%-40%; the content of the carrier is, for example, 10%, 17%, 20%, 25%, 48% or 50.6%.

[0014] In this invention, the alkaline earth metal oxide can be a conventionally selected alkaline earth metal oxide in the art, such as beryllium oxide, magnesium oxide, calcium oxide, strontium oxide or barium oxide, preferably magnesium oxide or calcium oxide.

[0015] In this invention, the NH3 adsorption capacity of the dehydrogenation catalyst precursor is preferably less than 60 μmol / g, more preferably less than 50 μmol / g, even more preferably less than 20 μmol / g, and may even be 0 μmol / g.

[0016] In this invention, the NH3 adsorption capacity of the dehydrogenation catalyst precursor is, for example, 12 μmol / g, 16 μmol / g, 25 μmol / g, 32 μmol / g, 35 μmol / g, 36 μmol / g, 40 μmol / g, 42 μmol / g, 43 μmol / g, 48 μmol / g, or 55 μmol / g.

[0017] In this invention, the dehydrogenation catalyst precursor may further include an auxiliary oxide.

[0018] The auxiliary oxide preferably includes one or more oxides of La, Na, K, Cr, Zn, In, Ce, Zr, Mo, Ni, Ru and Mn, and more preferably includes one or two oxides of Zn or Zr.

[0019] Preferably, the content of the auxiliary oxide is 5%-50%, where the percentage is the mass of the auxiliary oxide relative to the total mass of the dehydrogenation catalyst precursor.

[0020] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor includes CuO, ZnO and MgO, wherein the content of CuO is 44.5%, the content of ZnO is 45.5%, and the content of MgO is 10%.

[0021] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor comprises CuO, ZnO and CaO, wherein the content of CuO is 46.9%, the content of ZnO is 48.1%, and the content of CaO is 5%.

[0022] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor includes CuO, ZnO and CaO, wherein the content of CuO is 39.5%, the content of ZnO is 40.5%, and the content of CaO is 20%.

[0023] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor comprises CuO, ZnO and CaO, wherein the content of CuO is 63.8%, the content of ZnO is 26.2%, and the content of CaO is 10%.

[0024] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor includes CuO, ZnO and CaO, wherein the content of CuO is 44.7%, the content of ZnO is 15.3%, and the content of CaO is 40%.

[0025] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor includes CuO, ZnO and MgO, wherein the content of CuO is 39.5%, the content of ZnO is 40.5%, and the content of MgO is 20%.

[0026] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor includes CuO, ZrO2 and MgO, wherein the content of CuO is 42.3%, the content of ZrO2 is 32.7%, and the content of MgO is 25%.

[0027] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor comprises CuO and MgO, wherein the content of CuO is 49.4% and the content of MgO is 50.6%.

[0028] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor includes CuO, ZnO and MgO, wherein the content of CuO is 10%, the content of ZnO is 42%, and the content of MgO is 48%.

[0029] In a specific embodiment of the present invention, the dehydrogenation catalyst precursor includes CuO, ZnO and MgO, wherein the content of CuO is 75%, the content of ZnO is 8%, and the content of MgO is 17%.

[0030] This invention provides a method for preparing the dehydrogenation catalyst precursor as described above, comprising the following steps:

[0031] A precipitant aqueous solution and a metal salt aqueous solution are mixed to carry out a precipitation reaction; then post-processing is performed to obtain the final product; wherein, the metal salt aqueous solution includes copper salt and a carrier alkaline earth metal salt;

[0032] The precipitation reaction is carried out at a temperature of 30-90℃.

[0033] The endpoint pH of the precipitation reaction is 6.0-10.0.

[0034] In some embodiments of the present invention, the mixing method is to simultaneously add an aqueous solution of a precipitant and an aqueous solution of a metal salt.

[0035] In some embodiments of the present invention, the mixing method is to add an aqueous solution of a precipitant to an aqueous solution of a metal salt.

[0036] In this invention, the temperature of the precipitation reaction is preferably 40-80℃, for example, 60℃ or 70℃.

[0037] In this invention, the endpoint pH value of the precipitation reaction is preferably 7.0-9.0, for example 8.0 or 8.5.

[0038] In this invention, the copper salt preferably includes one or more of copper nitrate, copper sulfate, copper chloride, and copper acetate and their derivatives.

[0039] In this invention, the carrier alkaline earth metal salt preferably includes one or more of alkaline earth metal nitrates, hydrochlorides, and sulfates and their derivatives, and more preferably includes one or more of magnesium nitrate or calcium nitrate and their derivatives. The alkaline earth metal can be a conventionally selected alkaline earth metal in the art, such as beryllium, magnesium, calcium, strontium, or barium, preferably magnesium or calcium.

[0040] In this invention, the metal salt aqueous solution refers to the solution in which all metal salts are soluble in water.

[0041] In this invention, the aqueous solution of the metal salt preferably further includes an auxiliary metal salt. The auxiliary metal salt preferably includes one or more of the nitrates, carbonates, and sulfates and their derivatives of La, Na, K, Cr, Zn, In, Ce, Zr, Mo, Ni, Ru, and Mn, and more preferably includes one or two of zinc nitrate and zirconium nitrate and their derivatives.

[0042] In this invention, the molar concentration of the metal salt in the aqueous solution is preferably 0.2-5 mol / L, more preferably 0.5-2 mol / L, for example 0.6 mol / L, 0.8 mol / L, 1.0 mol / L, or 1.1 mol / L. The molar concentration of the metal salt refers to the total molar concentration of all metal salts in the aqueous solution.

[0043] In this invention, the precipitant in the aqueous precipitant solution can be a conventional soluble alkaline substance in the art, preferably including one or more of K2CO3, Na2CO3, NaOH, NaHCO3, and KOH. The aqueous precipitant solution refers to an aqueous solution of the aforementioned conventionally used soluble alkaline substances as precipitants in the art.

[0044] In this invention, the mass fraction of the precipitant in the aqueous precipitant solution can be 5%-30%, for example, 10%, 11% or 12%, where the percentage is the mass percentage of the precipitant in the aqueous precipitant solution.

[0045] In this invention, the post-processing can be carried out using conventional post-processing methods in the art, generally including aging, washing, filtering, drying, calcination and molding.

[0046] The aging process can be carried out using methods conventional in the art. The aging time is preferably 0.5-6 hours, for example, 2 hours, 3 hours, or 4 hours. The aging temperature is preferably 40-80°C, for example, 60°C or 70°C.

[0047] The washing process can be performed using methods conventional in the art. Preferably, the detergent used for washing is deionized water.

[0048] The filtering can be performed using methods conventional in the art.

[0049] The drying process can be carried out using methods conventional in the art. The drying time is preferably 8-24 hours, for example, 10 hours, 12 hours, or 20 hours. The drying temperature is preferably 80-150°C, for example, 100°C or 120°C.

[0050] The calcination can be carried out using methods conventional in the art. The calcination time is preferably 0.5-4 hours, for example, 1 hour, 2 hours, or 3 hours. The calcination temperature is preferably 300-500°C, for example, 360°C, 400°C, or 450°C.

[0051] The molding process can be carried out using conventional methods in the art, preferably compression molding, for example, compression molding into a cylindrical sheet.

[0052] This invention provides a dehydrogenation catalyst precursor, which is prepared by the method described above for preparing a dehydrogenation catalyst precursor.

[0053] The present invention provides a dehydrogenation catalyst, which is obtained by reduction of a dehydrogenation catalyst precursor as described above; the dehydrogenation catalyst includes an active component and a support, wherein the active component includes copper; the support includes one or more alkaline earth metal oxides.

[0054] In this invention, during the reduction process of the dehydrogenation catalyst precursor, CuO is reduced to copper; the support remains unchanged; when the dehydrogenation catalyst precursor also includes an auxiliary oxide, the auxiliary oxide will not be reduced.

[0055] In this invention, the reduction temperature is preferably 160-260℃, for example 210℃ or 230℃.

[0056] In this invention, the reduction time is preferably 1-72 hours, for example, 4 hours, 6 hours, 24 hours or 36 hours.

[0057] In this invention, the reducing atmosphere can be hydrogen or a mixture of hydrogen and an inert atmosphere. The inert atmosphere can be nitrogen or an inert gas; for example, argon.

[0058] In some embodiments of the present invention, the reducing atmosphere is a mixture of hydrogen and an inert atmosphere; wherein the volume percentage of hydrogen is preferably 0.5%-20%, for example 5%.

[0059] The present invention provides a dehydrogenation catalyst comprising an active component and a support; the active component comprises copper; the support comprises one or more alkaline earth metal oxides; the copper content is 8%-60%, and the support content is 7%-66%, wherein the percentages are the percentages of the mass of each component to the total mass of the dehydrogenation catalyst.

[0060] This invention provides the application of the dehydrogenation catalyst described above 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 200-300℃; and the pressure of the dehydrogenation reaction is 0-0.5 MPa.

[0061] The present invention also provides a dehydrogenation reaction for preparing methyl isobutyl ketone, which uses the dehydrogenation catalyst described above; the reactants for the dehydrogenation reaction include methyl isobutyl methanol; the temperature of the dehydrogenation reaction is 200-300°C; and the pressure of the dehydrogenation reaction is 0-0.5 MPa.

[0062] In this invention, the dehydrogenation reaction is preferably a gas-phase dehydrogenation reaction.

[0063] In some embodiments of the present invention, the reactant for the dehydrogenation reaction is methyl isobutyl methanol.

[0064] In this invention, the appropriate temperature of the dehydrogenation reaction is crucial for the dehydrogenation catalyst prepared by this invention. By controlling the temperature of the dehydrogenation reaction within the aforementioned range, this invention not only improves the conversion rate of methyl isobutyl methanol and ensures the activity of the dehydrogenation catalyst under long-term operation, but also reduces the generation of side reactions and ensures the selectivity of methyl isobutyl ketone. The preferred temperature of the dehydrogenation reaction is 210-250℃, for example, 230℃ or 240℃.

[0065] 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 preferred pressure for the dehydrogenation reaction is 0-0.2 MPa. Here, the pressure refers to the pressure of the reaction system under gauge pressure; 0 MPa corresponds to atmospheric pressure.

[0066] In this invention, the liquid hourly space velocity (LISH) of the dehydrogenation reaction can be 0.2-4.0 h⁻¹. -1 Preferably, it is 0.6-2.5h. -1 For example, 0.8h -1 1.0h -1 1.2h -1 Or 1.5h -1 .

[0067] In some embodiments of the present invention, the dehydrogenation reaction includes the following steps:

[0068] (1) The reaction raw materials are vaporized and then passed into a reactor loaded with the dehydrogenation catalyst to carry out a dehydrogenation reaction to obtain the product;

[0069] (2) The product is condensed and separated into gas and liquid to obtain methyl isobutyl ketone.

[0070] In step (1), the reactor is preferably a fixed-bed reactor. 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, with a tubular fixed-bed reactor being preferred.

[0071] In step (1), the raw material for the dehydrogenation reaction can be methyl isobutyl methanol.

[0072] In step (1), the carrier gas for the dehydrogenation reaction is preferably an inert gas. 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 described in this invention is, for example, one or more of argon, helium, and nitrogen, preferably nitrogen.

[0073] In step (2), the condensation is a conventional condensation method in the art.

[0074] In step (2), the gas-liquid separation is a conventional method in the art, such as gas-liquid separation in a separator.

[0075] 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.

[0076] The reagents and raw materials used in this invention are all commercially available.

[0077] The positive and progressive effects of this invention are as follows:

[0078] 1. The dehydrogenation catalyst precursor prepared by the method of the present invention has reduced acidic sites on its surface when reduced to obtain a dehydrogenation catalyst. When applied to the preparation of methyl isobutyl ketone, it can further reduce the occurrence of side reactions. The selectivity of the obtained methyl isobutyl ketone is above 90%, and can even reach above 99%, which is conducive to industrial promotion.

[0079] 2. The dehydrogenation catalyst prepared in this invention can be applied to the gas-phase reaction of catalyzing the preparation of methyl isobutyl ketone from methyl isobutyl methanol, which can significantly improve the conversion rate of methyl isobutyl methanol, with a conversion rate of over 94%, and even over 98%. Attached Figure Description

[0080] Figure 1 The image shows the XRD pattern of the dehydrogenation catalyst precursor prepared in Example 1.

[0081] Figure 2 The image shows the XRD pattern of the dehydrogenation catalyst precursor prepared in Example 2.

[0082] Figure 3 This is the GC-MS spectrum of methyl isobutyl ketone standard.

[0083] Figure 4 The image shows the GC-MS spectrum of methyl isobutyl ketone prepared in Example 1. Detailed Implementation

[0084] 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.

[0085] GC-MS system (Model: Agilent 5977B GC / MSD)

[0086] X-ray diffractometer (Model: BRUKER D8 ADVANCE)

[0087] Chemisorption analyzer (Model: AMI-300)

[0088] Methyl isobutyl methanol (CAS: 108-11-2)

[0089] Methyl isobutyl ketone (CAS: 108-10-1)

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

[0091] Zinc nitrate hexahydrate (CAS: 10196-18-6)

[0092] Magnesium nitrate hexahydrate (CAS: 13446-18-9)

[0093] Calcium nitrate tetrahydrate (CAS: 13477-34-4)

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

[0095] Sodium carbonate (CAS: 497-19-8)

[0096] The GC-MS spectrum of the methyl isobutyl ketone standard is shown below. Figure 3 As shown.

[0097] Example 1

[0098] 1. Preparation of dehydrogenation catalyst precursors

[0099] (1) Weigh 135g of copper nitrate trihydrate, 166g of zinc nitrate hexahydrate and 64g of magnesium nitrate hexahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0100] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0101] (3) Add solution B to solution A at a temperature of 70℃ to carry out precipitation reaction. Stop the reaction when the pH rises to 8.0 and maintain 70℃ for aging for 2 hours.

[0102] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 80°C for 20 hours, then roasted in a roasting furnace at 360°C for 4 hours, and finally compressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0103] The obtained dehydrogenation catalyst precursor contained 44.5% CuO, 10% MgO support, and approximately 45.5% ZnO auxiliary oxide.

[0104] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was determined to be 40 μmol / g using an AMI-300 chemisorption analyzer.

[0105] The above-mentioned dehydrogenation catalyst precursor was subjected to XRD analysis using an X-ray diffractometer. The obtained XRD pattern is shown in the figure. Figure 1 .

[0106] 2. Preparation of methyl isobutyl ketone

[0107] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced with hydrogen to obtain the dehydrogenation catalyst. The reduction temperature was 230℃ and the reduction time was 6h.

[0108] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 1.0 h⁻¹ -1 The raw material is vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 230°C and a pressure of atmospheric pressure. The reaction product is condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone. The obtained methyl isobutyl ketone is analyzed by GC-MS, and the GC-MS spectrum is shown below. Figure 4 .Will Figure 4 and Figure 3 As can be seen from the comparison, the product obtained in this embodiment is methyl isobutyl ketone.

[0109] Example 2

[0110] 1. Preparation of dehydrogenation catalyst precursors

[0111] (1) Weigh 143g of copper nitrate trihydrate, 176g of zinc nitrate hexahydrate and 21g of calcium nitrate tetrahydrate into a beaker, add 1300g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0112] (2) Weigh 170g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0113] (3) At a temperature of 40℃, solution B is added to solution A to carry out a precipitation reaction. The reaction is terminated when the pH rises to 7.0, and then the temperature is raised to 80℃ for 4 hours for aging.

[0114] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 120°C for 8 hours, then calcined in a calcining furnace at 450°C for 2 hours, and then pressed into tablets to obtain the dehydrogenation catalyst precursor.

[0115] The obtained dehydrogenation catalyst precursor contained 46.9% CuO, 5% CaO support, and approximately 48.1% ZnO auxiliary oxide.

[0116] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was measured on an AMI-300 chemisorption analyzer and found to be 35 μmol / g.

[0117] The above-mentioned dehydrogenation catalyst precursor was subjected to XRD analysis using an X-ray diffractometer. The obtained XRD pattern is shown in the figure. Figure 2 .

[0118] 2. Preparation of methyl isobutyl ketone

[0119] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced by a mixture of hydrogen and nitrogen (hydrogen volume ratio of 5%) to obtain the dehydrogenation catalyst. The reduction temperature was 230℃ and the reduction time was 24h.

[0120] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 0.6 h⁻¹ -1 The raw materials are vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 230°C and a normal pressure. The reaction products are condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone.

[0121] Example 3

[0122] 1. Preparation of dehydrogenation catalyst precursors

[0123] (1) Weigh 120g of copper nitrate trihydrate, 148g of zinc nitrate hexahydrate and 84g of calcium nitrate tetrahydrate into a beaker, add 1300g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0124] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0125] (3) At a temperature of 40℃, solution B and solution A were added to the reactor simultaneously for precipitation reaction, and the pH was maintained at 7.0. After the addition was completed, the temperature was raised to 70℃ and aged for 2 hours.

[0126] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 120°C for 8 hours, then calcined in a calcining furnace at 400°C for 4 hours, and then pressed into tablets to obtain the dehydrogenation catalyst precursor.

[0127] The obtained dehydrogenation catalyst precursor contained 39.5% CuO, 20% CaO support, and approximately 40.5% ZnO auxiliary oxide.

[0128] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was measured on an AMI-300 chemisorption analyzer and found to be 25 μmol / g.

[0129] 2. Preparation of methyl isobutyl ketone

[0130] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced with hydrogen to obtain the dehydrogenation catalyst. The reduction temperature was 210℃ and the reduction time was 6h.

[0131] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 1.0 h⁻¹ -1 The raw materials are vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 230°C and a normal pressure. The reaction products are condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone.

[0132] Example 4

[0133] 1. Preparation of dehydrogenation catalyst precursors

[0134] (1) Weigh 194g of copper nitrate trihydrate, 96g of zinc nitrate hexahydrate and 42g of calcium nitrate tetrahydrate into a beaker, add 1300g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0135] (2) Weigh 170g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0136] (3) At a temperature of 70℃, solution B and solution A were added to the reactor simultaneously to carry out precipitation reaction, and the pH was maintained at 8.5. After the addition was completed, the reactor was aged for 2 hours.

[0137] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 150°C for 8 hours, then roasted in a roasting furnace at 450°C for 3 hours, and finally compressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0138] The obtained dehydrogenation catalyst precursor contained 63.8% CuO, 10% CaO support, and approximately 26.2% ZnO auxiliary oxide.

[0139] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was measured on an AMI-300 chemisorption analyzer and found to be 32 μmol / g.

[0140] 2. Preparation of methyl isobutyl ketone

[0141] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced by a mixture of hydrogen and nitrogen (hydrogen volume ratio of 5%) to obtain the dehydrogenation catalyst. The reduction temperature was 230℃ and the reduction time was 36h.

[0142] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 1.2 h⁻¹ -1 The raw materials are vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 250°C and a normal pressure. The reaction products are condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone.

[0143] Example 5

[0144] 1. Preparation of dehydrogenation catalyst precursors

[0145] (1) Weigh 136g of copper nitrate trihydrate, 56g of zinc nitrate hexahydrate and 255g of magnesium nitrate hexahydrate into a beaker, add 1600g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.1mol / L) is denoted as solution A.

[0146] (2) Weigh 230g of sodium carbonate, add 2000g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0147] (3) At a temperature of 40℃, solution B and solution A were added to the reactor simultaneously for precipitation reaction, and the pH was maintained at 8.5. After the addition was completed, the temperature was raised to 80℃ and the aging continued for 3 hours.

[0148] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 120°C for 10 hours, then calcined in a calcining furnace at 400°C for 4 hours, and finally compressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0149] The obtained dehydrogenation catalyst precursor contained 44.7% CuO, 40% CaO support, and approximately 15.3% ZnO auxiliary oxide.

[0150] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was determined to be 12 μmol / g using an AMI-300 chemisorption analyzer.

[0151] 2. Preparation of methyl isobutyl ketone

[0152] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced with hydrogen to obtain the dehydrogenation catalyst. The reduction temperature was 230℃ and the reduction time was 6h.

[0153] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 0.8 h⁻¹ -1 The raw materials are vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 230°C and a normal pressure. The reaction products are condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone.

[0154] Example 6

[0155] 1. Preparation of dehydrogenation catalyst precursors

[0156] (1) Weigh 120g of copper nitrate trihydrate, 148g of zinc nitrate hexahydrate and 127g of magnesium nitrate hexahydrate into a beaker, add 1500g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0157] (2) Weigh 200g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 12%) is denoted as solution B.

[0158] (3) At a temperature of 40℃, solution B and solution A were added to the reactor simultaneously for precipitation reaction, and the pH was maintained at 7.0. After the addition was completed, the temperature was raised to 70℃ and the aging continued for 3 hours.

[0159] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 100°C for 12 hours, then roasted in a roasting furnace at 400°C for 2 hours, and finally compressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0160] The obtained dehydrogenation catalyst precursor contained 39.5% CuO, 20% MgO support, and approximately 40.5% ZnO auxiliary oxide.

[0161] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was measured on an AMI-300 chemisorption analyzer and found to be 36 μmol / g.

[0162] 2. Preparation of methyl isobutyl ketone

[0163] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced with hydrogen to obtain the dehydrogenation catalyst. The reduction temperature was 230℃ and the reduction time was 6h.

[0164] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 1.0 h⁻¹ -1 The raw materials are vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 250°C and a reaction pressure of 0.5 MPa. The reaction products are condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone.

[0165] Example 7

[0166] 1. Preparation of dehydrogenation catalyst precursors

[0167] (1) Weigh 128g of copper nitrate trihydrate, 114g of zirconium nitrate pentahydrate and 159g of magnesium nitrate hexahydrate into a beaker, add 1500g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 0.9mol / L) is denoted as solution A.

[0168] (2) Weigh 250g of sodium carbonate, add 2000g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 11%) is denoted as solution B.

[0169] (3) Add solution B to solution A at a temperature of 60℃ to carry out precipitation reaction. Stop adding precipitant solution when the pH rises to 9.0, and continue aging at 60℃ for 3 hours.

[0170] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 100°C for 12 hours, then roasted in a roasting furnace at 500°C for 1 hour, and finally compressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0171] The obtained dehydrogenation catalyst precursor contained 42.3% CuO, 25% MgO support, and 32.7% ZrO2 promoter oxide.

[0172] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was determined to be 43 μmol / g using an AMI-300 chemisorption analyzer.

[0173] 2. Preparation of methyl isobutyl ketone

[0174] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced with hydrogen to obtain the dehydrogenation catalyst. The reduction temperature was 230℃ and the reduction time was 4h.

[0175] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 1.5 h⁻¹ -1 The raw materials are vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 240°C and a normal pressure. The reaction products are condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone.

[0176] Example 8

[0177] 1. Preparation of dehydrogenation catalyst precursors

[0178] (1) Weigh 150g of copper nitrate trihydrate and 322g of magnesium nitrate hexahydrate into a beaker, add 1600g of deionized water to dissolve them completely, and the resulting aqueous solution of the metal salt (the molar concentration of the metal salt is 1.2mol / L) is denoted as solution A.

[0179] (2) Weigh 240g of sodium carbonate, add 2000g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 11%) is denoted as solution B.

[0180] By controlling the amount of the above raw materials, the CuO content in the obtained dehydrogenation catalyst precursor is 49.4%, and the MgO support content is 50.6%.

[0181] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was determined to be 55 μmol / g using an AMI-300 chemisorption analyzer.

[0182] The remaining conditions are the same as in Example 1.

[0183] Example 9

[0184] 1. Preparation of dehydrogenation catalyst precursors

[0185] (1) Weigh 30g of copper nitrate trihydrate, 175g of zinc nitrate hexahydrate and 268g of magnesium nitrate hexahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.3mol / L) is denoted as solution A.

[0186] (2) Weigh 220g of sodium carbonate, add 2000g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0187] By controlling the above-mentioned raw material dosages, the CuO content in the obtained dehydrogenation catalyst precursor is 10%, the ZnO content is 48%, and the MgO content is 42%.

[0188] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was determined to be 16 μmol / g using an AMI-300 chemisorption analyzer.

[0189] The remaining conditions are the same as in Example 1.

[0190] Example 10

[0191] 1. Preparation of dehydrogenation catalyst precursors

[0192] (1) Weigh 228g of copper nitrate trihydrate, 62g of zinc nitrate hexahydrate and 51g of magnesium nitrate hexahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0193] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0194] By controlling the amount of the above raw materials, the content of CuO in the obtained dehydrogenation catalyst precursor is 75%, the content of ZnO is 17%, and the content of MgO is 8%.

[0195] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was determined to be 48 μmol / g using an AMI-300 chemisorption analyzer.

[0196] The remaining conditions are the same as in Example 1.

[0197] Example 11

[0198] 1. Preparation of dehydrogenation catalyst precursors

[0199] (1) Weigh 135g of copper nitrate trihydrate, 166g of zinc nitrate hexahydrate and 64g of magnesium nitrate hexahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0200] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0201] (3) At a temperature of 30℃, solution B was added to solution A to carry out a precipitation reaction. The reaction was terminated when the pH rose to 8.0, and the temperature was maintained at 30℃ for 4 hours.

[0202] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 80°C for 20 hours, then roasted in a roasting furnace at 360°C for 4 hours, and finally compressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0203] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was determined to be 42 μmol / g using an AMI-300 chemisorption analyzer.

[0204] The remaining conditions are the same as in Example 1.

[0205] Example 12

[0206] 1. Preparation of dehydrogenation catalyst precursors

[0207] (1) Weigh 135g of copper nitrate trihydrate, 166g of zinc nitrate hexahydrate and 64g of magnesium nitrate hexahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0208] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0209] (3) Add solution B to solution A at a temperature of 90℃ to carry out precipitation reaction. Terminate the reaction when the pH rises to 8.0 and maintain aging at 90℃ for 2 hours.

[0210] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 80°C for 20 hours, then roasted in a roasting furnace at 360°C for 4 hours, and finally compressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0211] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was measured on an AMI-300 chemisorption analyzer and found to be 36 μmol / g.

[0212] The remaining conditions are the same as in Example 1.

[0213] Example 13

[0214] The preparation of the dehydrogenation catalyst precursor was the same as in Example 1, except that the reaction pressure was controlled at 0.2 MPa during the preparation of methyl isobutyl ketone, and the other conditions were kept the same as in Example 1.

[0215] Comparative Example 1

[0216] 1. Preparation of dehydrogenation catalyst precursors

[0217] (1) Weigh 240g of copper nitrate trihydrate and 120g of zinc nitrate hexahydrate into a beaker, add 1600g of deionized water to dissolve them completely, and the resulting metal salt aqueous solution is denoted as solution A.

[0218] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant is denoted as solution B.

[0219] (3) Add solution B to solution A and carry out the precipitation reaction at 50°C. Terminate the reaction when the pH rises to 7.0-7.2 and then heat to 60°C for 30 minutes to age.

[0220] (4) After aging, the slurry is filtered and washed. After washing, 50g of pseudoboehmite is added and stirred evenly. The resulting solid material is dried at 120℃ for 8 hours, then calcined in a calcining furnace at 450℃ for 2 hours. Finally, it is pressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0221] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was measured on an AMI-300 chemisorption analyzer and found to be 260 μmol / g.

[0222] 2. Preparation of methyl isobutyl ketone

[0223] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced with hydrogen to obtain the dehydrogenation catalyst. The reduction temperature was 230℃ and the reduction time was 6h.

[0224] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 1.0 h⁻¹ -1 The raw materials are vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 230°C and a normal pressure. The reaction products are condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone.

[0225] Comparative Example 2

[0226] 1. Preparation of dehydrogenation catalyst precursors

[0227] (1) Weigh 171g of copper nitrate trihydrate and 152g of zirconium nitrate pentahydrate into a beaker, add 1000g of deionized water to dissolve them completely, and the resulting aqueous solution of the metal salt (the molar concentration of the metal salt is 1.1mol / L) is denoted as solution A.

[0228] (2) Weigh 180g of sodium carbonate, add 1700g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0229] (3) Add solution B to solution A at a temperature of 60℃ to carry out precipitation reaction. Stop adding precipitant solution when the pH rises to 9.0, and continue aging at 60℃ for 3 hours.

[0230] (4) After aging, the slurry is filtered and washed. The resulting solid material is dried at 100°C for 12 hours, then roasted in a roasting furnace at 500°C for 1 hour, and finally compressed into cylindrical tablets to obtain the dehydrogenation catalyst precursor.

[0231] The obtained dehydrogenation catalyst precursor contained 56.3% CuO and 43.7% ZrO2 promoter oxide.

[0232] The adsorption capacity of the catalyst precursor NH3-TPD was determined to be 180 μmol / g using an AMI-300 chemisorption analyzer.

[0233] 2. Preparation of methyl isobutyl ketone

[0234] (1) The above-mentioned dehydrogenation catalyst precursor was loaded into a fixed bed reactor and reduced with hydrogen to obtain the dehydrogenation catalyst. The reduction temperature was 230℃ and the reduction time was 6h.

[0235] (2) Using methyl isobutyl methanol as raw material, with a liquid hourly space velocity of 1.0 h⁻¹ -1 The raw materials are vaporized in the vaporizer via a metering pump, and then mixed with nitrogen before entering the reactor. The reactor is maintained at a reaction temperature of 230°C and a normal pressure. The reaction products are condensed to room temperature and then separated into gas and liquid phases in a separator. The liquid reaction product is collected to obtain methyl isobutyl ketone.

[0236] Comparative Example 3

[0237] The preparation of the dehydrogenation catalyst precursor was the same as in Example 6, except that the reaction temperature was controlled at 350°C during the preparation of methyl isobutyl ketone, and the other conditions were kept the same as in Example 6.

[0238] Comparative Example 4

[0239] The preparation of the dehydrogenation catalyst precursor was the same as in Example 6, except that the reaction pressure was controlled at 4 MPa during the preparation of methyl isobutyl ketone, and the other conditions were kept the same as in Example 6.

[0240] Comparative Example 5

[0241] 1. Preparation of dehydrogenation catalyst precursors

[0242] (1) Weigh 135g of copper nitrate trihydrate, 166g of zinc nitrate hexahydrate and 74g of aluminum nitrate nonahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0243] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0244] By controlling the amount of the above raw materials, the content of CuO in the obtained dehydrogenation catalyst precursor is 44.5%, the content of ZnO is 45.5%, and the content of alumina is 10%.

[0245] The remaining conditions are the same as in Example 1.

[0246] Comparative Example 6

[0247] 1. Preparation of dehydrogenation catalyst precursors

[0248] (1) Weigh 258g of copper nitrate trihydrate, 18g of zinc nitrate hexahydrate and 65g of magnesium nitrate hexahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.0mol / L) is denoted as solution A.

[0249] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0250] By controlling the amount of the above raw materials, the content of CuO in the obtained dehydrogenation catalyst precursor is 85%, the content of ZnO is 5%, and the content of MgO is 10%.

[0251] The remaining conditions are the same as in Example 1.

[0252] Comparative Example 7

[0253] 1. Preparation of dehydrogenation catalyst precursors

[0254] (1) Weigh 15g of copper nitrate trihydrate, 165g of zinc nitrate hexahydrate and 320g of magnesium nitrate hexahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 1.4mol / L) is denoted as solution A.

[0255] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0256] By controlling the amount of the above raw materials, the content of CuO in the obtained dehydrogenation catalyst precursor is 5%, the content of ZnO is 45%, and the content of MgO is 50%.

[0257] The remaining conditions are the same as in Example 1.

[0258] Comparative Example 8

[0259] 1. Preparation of dehydrogenation catalyst precursors

[0260] (1) Weigh 148g of copper nitrate trihydrate, 182g of zinc nitrate hexahydrate and 12g of magnesium nitrate hexahydrate into a beaker, add 1350g of deionized water to dissolve them completely, and the resulting aqueous solution of metal salt (the molar concentration of the metal salt is 0.9mol / L) is denoted as solution A.

[0261] (2) Weigh 175g of sodium carbonate, add 1500g of deionized water to dissolve it, and the resulting aqueous solution of precipitant (mass fraction of 10%) is denoted as solution B.

[0262] By controlling the amount of the above raw materials, the content of CuO in the obtained dehydrogenation catalyst precursor is 48.4%, the content of ZnO is 49.6%, and the content of MgO is 2%.

[0263] The remaining conditions are the same as in Example 1.

[0264] Comparative Example 9

[0265] The final pH value of the precipitation reaction was controlled at 5.5, and the other conditions were kept the same as in Example 1.

[0266] The adsorption capacity of the dehydrogenation catalyst precursor NH3-TPD was measured on an AMI-300 chemisorption analyzer and found to be 96 μmol / g.

[0267] The main parameters and conditions in the preparation process of the dehydrogenation catalyst precursors in Examples 1-13 and Comparative Examples 1-9 are shown in Table 1.

[0268] Table 1

[0269]

[0270] The specific reaction conditions and results for the preparation of methyl isobutyl ketone in Examples 1-13 and Comparative Examples 1-9 are shown in Table 2, wherein:

[0271] (1) The formula for the conversion rate of methyl isobutyl methanol is:

[0272]

[0273] In the formula:

[0274] ω1: The mass fraction of methyl isobutyl methanol in the raw material, expressed as a percentage;

[0275] ω2: The mass fraction of methyl isobutyl methanol in the product, expressed as a percentage.

[0276] (2) The formula for calculating the selectivity of methyl isobutyl ketone is:

[0277]

[0278] In the formula:

[0279] ω1: The mass fraction of methyl isobutyl methanol in the raw material, expressed as a percentage;

[0280] ω2: The mass fraction of methyl isobutyl methanol in the product, expressed as a percentage (%).

[0281] ω3: The mass fraction of methyl isobutyl ketone in the product, expressed as a percentage.

[0282] Table 2

[0283]

[0284]

[0285] According to Table 2:

[0286] Comparing the methyl isobutyl methanol conversion and methyl isobutyl ketone selectivity of Examples 1-13 and Comparative Examples 1-9, it can be seen that the dehydrogenation catalyst prepared in this invention, when used to catalyze the dehydrogenation reaction of methyl isobutyl methanol to obtain methyl isobutyl ketone, can achieve both higher methyl isobutyl methanol conversion and higher methyl isobutyl ketone selectivity. Specifically, the methyl isobutyl methanol conversion can reach over 94%, or even over 97%; and the methyl isobutyl ketone selectivity can reach 99% or higher.

[0287] The dehydrogenation catalyst precursors in Comparative Examples 1 and 5 were CuO-ZnO-Al2O3, which is outside the scope of this invention. A comparison of Comparative Examples 1, 5, and Example 1 shows that the dehydrogenation catalyst precursor in Example 1, CuO-ZnO-MgO, achieved a high methyl isobutyl methanol conversion rate of 96.8% and a methyl isobutyl ketone selectivity of 99.6% when used to catalyze the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone. However, Comparative Examples 1 and 5 could not simultaneously achieve both high methyl isobutyl methanol conversion and high methyl isobutyl ketone selectivity. In the research of dehydrogenation catalysts, the study of the support is crucial. Besides serving as the framework for the active components, dispersing them, and increasing catalyst strength, the support significantly influences the catalyst's activity and selectivity. Traditional copper-zinc-aluminum dehydrogenation catalysts, using alumina as the support, exhibit poor selectivity for the target product. When the support in the dehydrogenation catalyst is an alkaline earth metal oxide, the dehydrogenation catalyst obtained by reducing the dehydrogenation catalyst precursor exhibits superior performance, achieving both high conversion rates of methyl isobutyl methanol and high selectivity for methyl isobutyl ketone. This is likely because dehydrogenation catalysts using alumina as a support have abundant acidic sites on their surface, leading to more side reactions and poor selectivity for the target product, thus failing to achieve both high conversion rates of methyl isobutyl methanol and high selectivity for methyl isobutyl ketone. In contrast, the support in this invention comprises alkaline earth metal oxides, which reduces the acidic sites on the catalyst surface, thereby increasing the conversion rate of the dehydrogenation reaction feedstock and suppressing side reactions, thus improving the selectivity of the target product.

[0288] The dehydrogenation catalyst precursor obtained in Comparative Example 2 does not include the MgO support and is not within the scope of protection of this invention. As can be seen from the comparison between Comparative Example 2 and Example 7, when the dehydrogenation catalyst precursor in Comparative Example 2 is reduced to obtain the dehydrogenation catalyst and used to catalyze the dehydrogenation reaction of methyl isobutyl methanol to obtain methyl isobutyl ketone, the conversion rate of methyl isobutyl methanol is 83.2% and the selectivity of methyl isobutyl ketone is 90.4%. However, when the dehydrogenation catalyst in Example 7 is used, the conversion rate of methyl isobutyl methanol is as high as 97.8% and the selectivity of methyl isobutyl ketone is 99.2%. It can be seen that when the dehydrogenation catalyst precursor includes a support, the dehydrogenation catalyst obtained by its reduction can significantly improve the conversion rate of the dehydrogenation reaction feedstock and the selectivity of the target product.

[0289] The dehydrogenation reaction temperature in Comparative Example 3 was 350°C, which is too high and outside the scope of this invention. A comparison between Comparative Example 3 and Example 6 shows that the selectivity of methyl isobutyl ketone in Comparative Example 3 was significantly reduced. This indicates that excessively high dehydrogenation temperatures reduce the catalytic activity of the dehydrogenation catalyst, hindering the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone, increasing byproducts, and thus significantly reducing the selectivity of methyl isobutyl ketone.

[0290] The dehydrogenation reaction pressure in Comparative Example 4 was 4 MPa, which is too high and outside the scope of this invention. A comparison between Comparative Example 4 and Example 6 shows that the conversion rate of methyl isobutyl methanol in Comparative Example 4 was significantly reduced. This indicates that excessively high pressure during the dehydrogenation reaction is detrimental to the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone, thus leading to a significant decrease in the conversion rate of methyl isobutyl methanol. This may be because the dehydrogenation of methyl isobutyl methanol to methyl isobutyl ketone is a process involving increasing system pressure; when the pressure of the dehydrogenation reaction is too high, it is unfavorable for the forward progress of the dehydrogenation reaction.

[0291] In Comparative Examples 6 and 7, the levels of copper oxide, the active component precursor, were either too high or too low, which are outside the scope of protection of this invention. Compared with Example 1, the conversion rates of methyl isobutyl methanol obtained in Comparative Examples 6 and 7 were significantly reduced. This indicates that an appropriate copper oxide content is beneficial for improving the conversion rate of methyl isobutyl methanol while maintaining a high selectivity for methyl isobutyl ketone. This may be because when the copper oxide content in the dehydrogenation catalyst precursor is too high or too low, the resulting dehydrogenation catalyst cannot effectively catalyze the dehydrogenation reaction of methyl isobutyl methanol to obtain methyl isobutyl ketone.

[0292] The support content in Comparative Example 8 was 2%, which is too low and not within the scope of protection of this invention. A comparison between Comparative Example 8 and Example 1 shows that the conversion rate of methyl isobutyl methanol and the selectivity of methyl isobutyl ketone obtained in Comparative Example 8 were significantly lower than those in Example 1. This demonstrates that an appropriate support content is crucial for achieving both high methyl isobutyl methanol conversion and high methyl isobutyl ketone selectivity. This may be because when the support content in the dehydrogenation catalyst precursor is low, the support content in the resulting dehydrogenation catalyst is also low, failing to effectively form reaction sites for the dehydrogenation reaction and reduce acidic sites in the dehydrogenation catalyst. This hinders the dehydrogenation reaction and the yield of methyl isobutyl ketone from methyl isobutyl methanol.

[0293] The endpoint pH of the precipitation reaction in Comparative Example 9 was 5.5, which is too low and outside the scope of protection of this invention. A comparison between Comparative Example 9 and Example 1 shows that the conversion rate of methyl isobutyl methanol and the selectivity of methyl isobutyl ketone in Comparative Example 9 were significantly reduced. This is because the endpoint pH of the precipitation reaction is a key factor in the synthesis of the dehydrogenation catalyst precursor. The endpoint pH of the precipitation reaction determines the structure and surface properties of the dehydrogenation catalyst precursor, and therefore has a significant impact on the structure and performance of the dehydrogenation catalyst obtained by reducing the dehydrogenation catalyst precursor. In this invention, the endpoint pH of the precipitation reaction is 6.0-10.0, which is higher and helps to reduce the acidic sites in the obtained dehydrogenation catalyst precursor, thereby reducing side reactions and improving the selectivity of methyl isobutyl ketone.

[0294] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. The application of a dehydrogenation catalyst in the dehydrogenation reaction for the preparation of methyl isobutyl ketone; in, The reactants for the dehydrogenation reaction include methyl isobutyl methanol; the temperature of the dehydrogenation reaction is 200-300℃; and the pressure of the dehydrogenation reaction is 0-0.5 MPa. The dehydrogenation catalyst is obtained by reducing a dehydrogenation catalyst precursor; the dehydrogenation catalyst includes an active component and a support, wherein the active component includes copper; and the support includes one or more alkaline earth metal oxides. The dehydrogenation catalyst precursor comprises an active component precursor and a support; wherein the active component precursor comprises copper oxide; the support comprises one or more alkaline earth metal oxides; the content of copper oxide is 30%-49.4%; the content of the support is 20%-40%; wherein the percentages are the mass percentage of each component to the total mass of the dehydrogenation catalyst precursor; the NH3 adsorption capacity of the dehydrogenation catalyst precursor is less than 90 μmol / g; the dehydrogenation catalyst precursor also includes an auxiliary oxide; the auxiliary oxide comprises one or both of Zn or Zr elements. The alkaline earth metal oxide is magnesium oxide or calcium oxide; The content of the auxiliary oxide is 15.3%-50%, and the percentage is the percentage of the mass of the auxiliary oxide to the total mass of the dehydrogenation catalyst precursor.

2. The application of the dehydrogenation catalyst as described in claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In the dehydrogenation catalyst precursor, the content of copper oxide is 39.5%, 42.3%, 44.5%, 44.7%, 46.9%, or 49.4%.

3. The application of the dehydrogenation catalyst as described in claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, In the dehydrogenation catalyst precursor, the content of the support is 20% or 25%.

4. The application of the dehydrogenation catalyst as described in claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The NH3 adsorption capacity of the dehydrogenation catalyst precursor is less than 60 μmol / g.

5. The application of the dehydrogenation catalyst as described in claim 4 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The NH3 adsorption capacity of the dehydrogenation catalyst precursor is less than 50 μmol / g.

6. The application of the dehydrogenation catalyst as described in claim 5 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The NH3 adsorption capacity of the dehydrogenation catalyst precursor is less than 20 μmol / g.

7. The application of the dehydrogenation catalyst as described in claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The NH3 adsorption capacity of the dehydrogenation catalyst precursor is 12 μmol / g, 16 μmol / g, 25 μmol / g, 32 μmol / g, 35 μmol / g, 36 μmol / g, 40 μmol / g, 42 μmol / g, 43 μmol / g, 48 μmol / g, or 55 μmol / g.

8. The application of the dehydrogenation catalyst as described in claim 1 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The method for preparing the dehydrogenation catalyst precursor includes the following steps: A precipitant aqueous solution and a metal salt aqueous solution are mixed to carry out a precipitation reaction; then post-processing is performed to obtain the final product; wherein, the metal salt aqueous solution includes copper salt and a carrier alkaline earth metal salt; The precipitation reaction is carried out at a temperature of 30-90℃. The endpoint pH of the precipitation reaction is 6.0-10.

0.

9. The application of the dehydrogenation catalyst as described in claim 8 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The mixing method includes simultaneously adding an aqueous solution of a precipitant and an aqueous solution of a metal salt, or adding an aqueous solution of a precipitant to an aqueous solution of a metal salt.

10. The application of the dehydrogenation catalyst according to claim 9 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The precipitation reaction is carried out at a temperature of 40-80℃.

11. The application of the dehydrogenation catalyst according to claim 10 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The precipitation reaction is carried out at a temperature of 60°C or 70°C.

12. The application of the dehydrogenation catalyst according to claim 9 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The endpoint pH of the precipitation reaction is 7.0-9.

0.

13. The application of the dehydrogenation catalyst according to claim 12 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The endpoint pH of the precipitation reaction is 8.0 or 8.

5.

14. The application of the dehydrogenation catalyst according to claim 9 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The copper salt includes one or more of copper nitrate, copper sulfate, copper chloride, and copper acetate.

15. The application of the dehydrogenation catalyst according to claim 14 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The carrier alkaline earth metal salt includes one or more of the alkaline earth metal nitrates, hydrochlorides, and sulfates.

16. The application of the dehydrogenation catalyst according to claim 9 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The aqueous solution of the metal salt also includes an auxiliary metal salt, which includes one or both of zinc nitrate and zirconium nitrate.

17. The application of the dehydrogenation catalyst according to claim 9 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The molar concentration of the metal salt in the aqueous solution of the metal salt is 0.2-5 mol / L.

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 molar concentration of the metal salt in the aqueous solution of the metal salt is 0.5-2 mol / L.

19. The application of the dehydrogenation catalyst according to claim 9 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The precipitant in the aqueous solution is an alkaline substance.

20. The application of the dehydrogenation catalyst according to claim 19 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, It includes one or more of K2CO3, Na2CO3, NaOH, NaHCO3, and KOH.

21. The application of the dehydrogenation catalyst according to claim 9 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The mass fraction of the precipitant in the aqueous precipitant solution is 5%-30%, and the percentage is the mass percentage of the precipitant in the aqueous precipitant solution.

22. The application of the dehydrogenation catalyst according to claim 9 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The post-processing includes aging, washing, filtering, drying, calcination, and shaping; The aging time is 0.5-6 hours; The aging temperature is 40-80℃; The detergent used for washing is deionized water; The drying time is 8-24 hours; The drying temperature is 80-150℃; The roasting time is 0.5-4 hours; The roasting temperature is 300-500℃; The molding method is tablet molding.

23. 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 reduction temperature is 160-260℃.

24. The application of the dehydrogenation catalyst according to claim 23 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The reduction temperature is 210℃ or 230℃.

25. 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 restoration time is 1-72 hours.

26. 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 restoration time is 4h, 6h, 24h or 36h.

27. 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 reducing atmosphere is hydrogen or a mixture of hydrogen and an inert atmosphere; wherein, in the mixture of hydrogen and an inert atmosphere, the volume percentage of hydrogen is 0.5%-20%.

28. The use of the dehydrogenation catalyst according to any one of claims 1 to 27 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The dehydrogenation reaction includes the following steps: vaporizing the reaction raw material, then passing it into a reactor loaded with the dehydrogenation catalyst for reaction, and obtaining the product after condensation and gas-liquid separation; wherein, the reactor is a fixed-bed reactor.

29. The use of the dehydrogenation catalyst as described in claim 28 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The reactor is a tubular fixed-bed reactor, an axially adiabatic fixed-bed reactor, or a radially adiabatic fixed-bed reactor.

30. The use of the dehydrogenation catalyst as described in claim 28 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The dehydrogenation reaction is a gas-phase dehydrogenation reaction.

31. The application of the dehydrogenation catalyst as described in claim 28 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The dehydrogenation reaction is carried out at a temperature of 210-250℃.

32. The application of the dehydrogenation catalyst as described in claim 31 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The dehydrogenation reaction is carried out at a temperature of 230°C or 240°C.

33. The application of the dehydrogenation catalyst as described in claim 28 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The pressure of the dehydrogenation reaction is 0-0.2 MPa.

34. The application of the dehydrogenation catalyst as described in claim 28 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The liquid hourly space velocity (LHSV) of the dehydrogenation reaction is 0.2-4.0 h⁻¹. -1 .

35. The use of the dehydrogenation catalyst as described in claim 34 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The liquid hourly space velocity (LHSV) of the dehydrogenation reaction is 0.6-2.5 h⁻¹. -1 .

36. The use of the dehydrogenation catalyst as described in claim 35 in the dehydrogenation reaction for the preparation of methyl isobutyl ketone, characterized in that, The liquid hourly space velocity (LHSV) for the dehydrogenation reaction is 0.8 h⁻¹. -1 1.0h -1 1.2h -1 Or 1.5h -1 .

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