Preparation of a composite carrier-supported bimetallic catalyst for catalyzing the selective in-situ hydrogenation of carbon-oxygen double bonds

Abstract

The present invention discloses a method for preparing a composite carrier-supported bimetallic catalyst for catalyzing the selective in-situ hydrogenation of carbon-oxygen double bonds. The method is to prepare a metal oxide composite carrier-supported bimetallic active site catalyst, and then apply the catalyst to the reaction of selective catalytic hydrogenation of carbon-oxygen double bonds. The present invention utilizes the multifunctionality of the composite carrier and the advantages of high dispersion of the support, the interaction of the bimetallic, the regulation of the electronic structure and the mutual stability, to achieve selective catalytic hydrogenation of carbon-oxygen double bonds. The catalyst is simple to prepare, economical, has high catalytic activity, and the metal site is not easy to lose. It can realize the function of hydrogenating carbon-oxygen double bonds at various positions. The catalyst has broad application prospects in the application of selective hydrogenation.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of chemical intermediates and relates to a method for catalyzing selective in-situ hydrogenation of carbon-oxygen double bonds. Background Art

[0002] The hydrogenation reduction of carbon-oxygen double bonds is an important chemical intermediate reaction with broad application prospects. Among them, the selective hydrogenation reduction of ketones can be used to prepare alcohols, but other unsaturated functional groups can still be retained, which plays an important role in pharmaceutical intermediates; the catalytic hydrogenation of carbon dioxide to prepare formic acid and its derivatives has important and far-reaching significance for the achievement of carbon neutrality and carbon peak goals.

[0003] The catalysts mainly used in the reaction process can be divided into two types: homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts have obvious shortcomings such as being difficult to separate from reactants and products and difficult to recycle. At present, heterogeneous catalysts have become a more economical and practical way to catalyze the reaction. In addition, in the hydrogenation reaction of unsaturated bonds, it is often necessary to carry out the reaction under the action of hydrogen donors such as hydrogen and formic acid. Due to the limitations in the reaction process, this has hindered its development to a certain extent. Therefore, it is particularly important to prepare a stable and highly active in-situ hydrogenation catalyst.

[0004] Huang Hanmin et al. reported a metal complex catalyst for the selective hydrogenation of β-substituted unsaturated ketones, achieving a selectivity of up to 97% ee; the metal complex catalyst showed high catalytic activity in the reaction. However, the system still has disadvantages such as difficult catalyst recovery, the need for external hydrogen, and difficulty in product separation and purification. This makes this type of catalyst have certain limitations in practical applications. (Organic Letters, 2014, 16(15): 3912-3915.).

[0005] Chinese patent application number 201910288391.4 discloses a selective C=O bond hydrogenation catalyst and a preparation method thereof. This type of catalyst is applied to the selective hydrogenation reaction of cinnamaldehyde and shows good catalytic activity and recyclability. However, the preparation process of the catalyst is complicated, which is not conducive to practical operation.

[0006] As can be seen from the above, the methods for selective hydrogenation of carbon-oxygen double bonds reported in the current literature and patents have disadvantages such as complicated catalyst preparation and harsh reaction conditions. In addition, the use of high-pressure hydrogen as a hydrogen source has high equipment requirements, and hydrogen is a flammable and explosive gas, which may bring certain safety costs, thereby limiting the large-scale production application of selective hydrogenation in the chemical industry. Summary of the invention

[0007] Purpose of the invention: The purpose of the present invention is to provide a method for preparing an efficient and stable catalyst and a method for selective hydrogenation of carbon-oxygen double bonds.

[0008] Technical solution: In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0009] A carbon-oxygen double bond selective in-situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2 is prepared by the following method:

[0010] 1) Weigh Cu(NO3)2·3H2O, RuCl3, ZrO2-SO3-SiO2 and other substances in a mass ratio of (1-10):(1-10):(98-80), place them in a round-bottom flask, add 50-300 mL of water and stir thoroughly;

[0011] 2) placing the mixed liquid in step 1 in an oven to dry the water, the drying temperature is 100-150° C., and the drying time is: 12-36 hours; the catalyst precursor 1 can be obtained;

[0012] 3) taking out the catalyst precursor in step 2, grinding it into powder and placing it in a ceramic crucible for calcination at a temperature of 300 to 500° C. for a calcination time of 2 to 8 hours to obtain a precursor 2;

[0013] 4) The catalyst precursor 2 prepared in step 3 is placed in a tubular furnace and reduced by introducing gas, wherein the introduced gas is H2 or CO or a mixture of H2 and CO, the reduction temperature is 300-600°C, and the reduction time is 2-6h.

[0014] 5) The Cu-Ru / ZrO2-SO3-SiO2 catalyst for selective in-situ hydrogenation of carbon-oxygen double bonds prepared according to claim 1 is applied to an experiment for in-situ selective hydrogenation of carbon-oxygen double bonds, which is characterized by comprising the following steps:

[0015] 6) The carbon-oxygen double bond selective in situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2 prepared according to claim 1, a compound containing a carbon-oxygen double bond as a substrate (such as ethyl levulinate, benzaldehyde, acetophenone, furfural), and a solvent are added into a reactor to form a reaction system.

[0016] 7) The reaction is carried out at a temperature of 120-200° C. under the protection of an inert gas for 0.01-10 hours, and after the reaction is completed, separation and purification are performed to achieve selective hydrogenation of the carbon-oxygen double bond.

[0017] 8) The solvent is methanol, ethanol, isopropanol, sec-butanol, preferably isopropanol.

[0018] Beneficial effects: Compared with the existing technology, the advantages of the present invention include: the present invention adopts a carbon-oxygen double bond selective in-situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2 prepared by a simple and easy-to-operate impregnation method. The prepared carbon-oxygen double bond selective in-situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2 has the advantages of good metal dispersion, small metal particle size, high hydrogenation activity, can be recycled for multiple times and maintain high reaction activity. In addition, the shortcomings of high temperature and high pressure in the process of carbon-oxygen double bond in-situ selective hydrogenation reaction are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The X-ray diffraction pattern (XRD pattern) of the prepared catalyst is shown as follows:

[0020] Figure 2 Transmission electron microscopy (TEM) image of the prepared catalyst

[0021] Figure 3 Nitrogen adsorption-desorption curve and pore size distribution of the prepared catalyst

[0022] Figure 4 The test analysis diagram shows the effects of reaction temperature, reaction time and catalyst amount on the transfer hydrogenation of ethyl levulinate to prepare γ-valerolactone

[0023] Figure 5 Catalyst recycling diagram

[0024] Table 1 Effect of different catalysts on the transfer hydrogenation of ethyl levulinate to prepare γ-valerolactone

[0025] Table 2 shows the test analysis of the effect of different reaction solvents on the transfer hydrogenation of ethyl levulinate to prepare γ-valerolactone

[0026] Table 3 shows the reaction performance test of different compounds containing carbon-oxygen double bonds in this reaction system

[0027] Table 4 shows the specific surface area, pore volume and average pore diameter of the catalysts DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation mode of the present invention is described in detail below in conjunction with specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the claims attached to the application.

[0029] 1. Preparation of Cu-Ru / ZrO2-SO3-SiO2 Catalyst for Selective In-situ Hydrogenation of Carbon and Oxygen Double Bonds

[0030] The specific preparation process is as follows:

[0031] 0.378g Cu(NO3)2·3H2O, 0.2045g RuCl3·3H2O and 1.9g ZrO2-SO3-SiO2 carrier were placed in a flask, 100mL deionized water was added and stirred for 12h. After the reaction was completed, it was placed in an oven at 120℃ to dry and remove moisture. After drying, it was taken out and ground into powder with a mortar, and placed in a ceramic crucible and calcined at 400℃ for 4h. The calcined catalyst precursor was then placed in a tubular furnace and reduced with hydrogen at 450℃ for 2h to obtain the carbon-oxygen double bond selective in situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2. The catalysts prepared at different reduction temperatures were named Cu-Ru / ZrO2-SO3-SiO2-350, Cu-Ru / ZrO2-SO3-SiO2-450, and Cu-Ru / ZrO2-SO3-SiO2-550, respectively.

[0032] The following will discuss the effect of different reduction temperatures on the prepared carbon-oxygen double bond selective in situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2.

[0033] Depend on Figure 1 It can be seen that the XRD characteristic diffraction peaks of the prepared carbon-oxygen double bond selective in-situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2 do not have obvious diffraction peaks of Cu, Ru and their oxides. According to the corresponding standard card comparison, it is found that the main XRD diffraction peaks of the catalyst are ZrO2 and SiO2 in the carrier.

[0034] Depend on Figure 2 It can be seen that the prepared catalyst has good metal dispersion, and high-resolution TEM further confirms the loading of Cu and Ru bimetallics.

[0035] Depend on Figure 3 As shown in Table 1, the prepared catalysts are all mesoporous catalysts. As the specific surface area of ​​the metal-supported catalyst decreases, it indicates that the catalyst is dispersed on the surface of the catalyst carrier. In addition, the pore size distribution of the catalyst is very uniform.

[0036] Table 1

[0037]

[0038] a Specific surface area. b Pore ​​volume. cAverage pore size distribution byBJH. d Calculated by ICP-OES analysis.

[0039] 2. Using the above catalyst to prepare γ-valerolactone from ethyl levulinate

[0040] The specific preparation process is as follows:

[0041] A certain amount of carbon-oxygen double bond selective in-situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2, 1mmol ethyl levulinate and 5mL isopropanol were added to a 15mL thick-walled pressure tube in sequence, and the air in the pressure tube was removed with a nitrogen gas flow, and then the pressure tube was sealed and placed in an oil bath pot set to the reaction temperature for reaction, and stirring was continued during the reaction. After the tape was finished, it was cooled to room temperature, and the product was detected and analyzed by gas chromatograph, and the conversion rate of ethyl levulinate and the yield of γ-valerolactone were calculated by area normalization method.

[0042] (1) Comparison of catalyst performance

[0043] Table 2 Catalytic performance of catalysts prepared under different conditions

[0044]

[0045]

[0046]

[0047] Reaction conditions: EL 1mmol, catalyst 100mg, 2-PrOH 5mL, 180℃, 12h, N2. a mixture of Ru / ZrO2-SO3-SiO2-450 and Cu / ZrO2-SO3-SiO2-450, b 5wt%H2O added, c conducted in the air.

[0048] As shown in Table 2, compared with the bimetallic supported catalysts prepared under other conditions, the carbon-oxygen double bond selective in-situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2 showed higher catalytic activity in the in-situ selective hydrogenation of ethyl levulinate to prepare γ-valerolactone. The conversion rate of ethyl levulinate was 100%, and the yield of γ-valerolactone was 100%. Therefore, in the following test, we chose the Cu-Ru / ZrO2-SO3-SiO2-450 catalyst as an example for exploration.

[0049] (2) Reaction temperature, reaction time and catalyst amount

[0050] Depend on Figure 4 It can be seen that when the reaction temperature reaches 180°C and the reaction time is 12h, the conversion rate of ethyl levulinate reaches 100% and the yield of γ-valerolactone reaches 100%. However, when the reaction temperature is further increased to 200°C and the reaction time is further extended, the yield of γ-valerolactone and the conversion rate of ethyl levulinate both decrease.

[0051] (3) Research on different hydrogen-donating solvents

[0052] Table 3 Reaction performance test of different hydrogen donor solvents and different levulinic esters in the reaction system a

[0053]

[0054] a Reaction conditions: EL 1mmol, catalyst 100mg, 2-PrOH 5mL, 180℃, 12h, N2.

[0055] The amount of catalyst was controlled to be 100 mg, the reaction time was 12 h, 5 mL of methanol was used as the hydrogen supply solvent, 1 mmol of ethyl levulinate was added, and the reaction temperature was controlled at 180° C. γ-valerolactone was prepared under the above conditions, and then the conversion rate of ethyl levulinate and the yield of γ-valerolactone were calculated respectively, and the test results shown in Table 3 were obtained.

[0056] The amount of catalyst was controlled to be 100 mg, the reaction time was 12 h, 5 mL of ethanol was used as the hydrogen supply solvent, 1 mmol of ethyl levulinate was added, and the reaction temperature was controlled at 180° C. γ-valerolactone was prepared under the above conditions, and then the conversion rate of ethyl levulinate and the yield of γ-valerolactone were calculated respectively, and the test results shown in Table 3 were obtained.

[0057] The amount of catalyst was controlled to be 100 mg, the reaction time was 12 h, 5 mL of isopropanol was used as the hydrogen supply solvent, 1 mmol of ethyl levulinate was added, and the reaction temperature was controlled at 180° C. γ-valerolactone was prepared under the above conditions, and then the conversion rate of ethyl levulinate and the yield of γ-valerolactone were calculated respectively, and the test results shown in Table 3 were obtained.

[0058] The amount of catalyst was controlled to be 100 mg, the reaction time was 12 h, 5 mL of sec-butyl alcohol was used as the hydrogen supply solvent, 1 mmol of ethyl levulinate was added, and the reaction temperature was controlled at 180° C. γ-valerolactone was prepared under the above conditions, and then the conversion rate of ethyl levulinate and the yield of γ-valerolactone were calculated respectively, and the test results shown in Table 3 were obtained.

[0059] The amount of catalyst was controlled to be 100 mg, the reaction time was 12 h, 5 mL of 3-pentanol was used as a hydrogen supply solvent, 1 mmol of ethyl levulinate was added, and the reaction temperature was controlled at 180° C. γ-valerolactone was prepared under the above conditions, and then the conversion rate of ethyl levulinate and the yield of γ-valerolactone were calculated respectively, and the test results shown in Table 3 were obtained.

[0060] It can be seen from Table 3 that when sec-butyl alcohol and 3-pentanol are used as hydrogen supply solvents, at a reaction temperature of 180° C., the conversion rate of ethyl levulinate reaches more than 95%, and the yield of γ-valerolactone reaches more than 90%.

[0061] (4) In situ selective hydrogenation of other compounds containing carbon-oxygen double bonds

[0062] Table 4 In situ selective hydrogenation expansion of compounds containing carbon-oxygen double bonds

[0063]

[0064] a Reaction conditions: substrate 1mmol, Cu-Ru / ZrO2-SO3-SiO2100mg, 2-PrOH5mL, 180℃, 12h, N2.

[0065] 1 mmol of the compound containing a carbon-oxygen double bond in Table 4 was taken respectively, the reaction temperature was controlled at 180°C, and the reaction time was 12 h. Under the above reaction conditions, it was subjected to in-situ selective hydrogenation, and then the conversion rate of the substrate and the yield of the product were calculated respectively, and the test results shown in Table 4 were obtained.

[0066] As shown in Table 4, the catalyst has a high hydrogenation activity for compounds containing carbon-oxygen double bonds, the conversion rate of the substrates reaches more than 90%, and the yield of most products can reach more than 99%.

[0067] (5) Evaluation of catalyst circulation effect

[0068] The amount of the carbon-oxygen double bond selective in-situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2 was 100 mg, the reaction temperature was controlled to be 180°C, and the reaction time was 12 h. The catalyst was then used repeatedly 1-5 times to prepare γ-valerolactone under the above reaction conditions, and then the conversion rate of ethyl levulinate and the yield of γ-valerolactone were calculated respectively to obtain the following: Figure 5 The test results are shown.

[0069] Depend on Figure 5 It can be seen that as the number of times the catalyst is reused increases, the conversion rate of LA remains almost 100%, indicating that the carbon-oxygen double bond selective in situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2 shows high activity and stability after repeated use.

[0070] The above embodiments are investigated by the influence of different preparation conditions on the catalyst, reaction temperature, reaction time, catalyst dosage and other conditions on the catalytic transfer of ethyl levulinate to prepare γ-valerolactone reaction performance, and the best catalyst is Cu-Ru / ZrO2-SO3-SiO2-450, the reaction temperature is 180°C, the catalyst dosage is 100mg, and the reaction time is 12h. Under the conditions, 100% γ-valerolactone yield and 100% conversion rate of ethyl levulinate are obtained. The catalyst has shown higher activity for the conversion of ethyl levulinate and the yield of γ-valerolactone, the reaction conditions are mild, and the raw materials and products are green and environmentally friendly, cheap and easy to obtain and can all be derived from renewable resources such as biomass. In addition, the multiple circulation effect is stable and easy to recycle. Therefore, the technical scheme has a considerable positive effect on the research of in-situ selective hydrogenation of carbon-oxygen double bonds.

[0071] Finally, it should be noted that the above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novelties disclosed herein.

Claims

1. A catalyst for catalyzing the selective in-situ hydrogenation of carbon-oxygen double bonds, characterized in that: The catalyst is prepared by loading the active components Cu and Ru particles on a metal oxide composite carrier through impregnation, calcination and reduction. The preparation method is as follows: 1) Weigh a certain mass ratio of Cu(NO3)2·3H2O, RuCl3, and ZrO2-SO3-SiO2 (1-10):(1-10):(98-80), place in a round-bottom flask, add appropriate amount of water and stir thoroughly; 2) placing the mixed liquid in step 1 in an oven and drying the water at 100-150° C. for 12-36 hours to obtain a catalyst precursor 1; 3) taking out the catalyst precursor in step 2, grinding it into powder and placing it in a ceramic crucible and calcining it at 300-500° C. for 2-8 hours to obtain precursor 2; 4) The catalyst precursor 2 prepared in step 3 is placed in a tubular furnace and introduced with a reducing gas for calcination reduction at 300-600° C. for 2-6 hours to finally obtain a carbon-oxygen double bond selective in-situ hydrogenation catalyst Cu-Ru / ZrO2-SO3-SiO2.

2. A catalyst for catalyzing the selective in-situ hydrogenation of carbon-oxygen double bonds according to claim 1, characterized in that: In step 1), the reaction temperature is room temperature, the stirring speed is 600-800 rpm, and the stirring time is 6-12 h.

3. A catalyst for catalyzing the selective in-situ hydrogenation of carbon-oxygen double bonds according to claim 1, characterized in that: In step 4), the precursor is reduced under reducing gas conditions at 450-600° C., and the calcination time is 2-6 hours.

4. The use of the catalyst for catalyzing the selective in-situ hydrogenation of carbon-oxygen double bonds as claimed in claim 1 for catalyzing the selective hydrogenation of carbon-oxygen double bonds, characterized in that it comprises the following steps: 1) adding the catalyst for catalyzing selective in-situ hydrogenation of carbon-oxygen double bonds, a substrate containing carbon-oxygen double bonds, and a solvent into a reactor to form a reaction system, wherein the mass of the substrate in the system is 0.01-2 mmol, and the mass ratio of the catalyst to the substrate containing carbon-oxygen double bonds is 0.5-2.0; 2) The reaction system in step 1 is set at a reaction temperature of 100-200° C., and the reaction is carried out for 0.01-10 hours under the protection of an inert gas. After the reaction is completed, the product is separated and purified to obtain the product; 3) The reaction system solvent in step 1 is methanol, ethanol, isopropanol, sec-butanol, and 3-pentanol.

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