Oxide-loaded heterogeneous catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, and provides an oxide-loaded heterogeneous catalyst as well as a preparation method and application thereof. The oxide-loaded heterogeneous catalyst comprises an oxide carrier and an active metal component covalently loaded on the oxide carrier, the active metal component is selected from at least one of Rh, Pb, Ir and Ru; the content of the active metal component in the catalyst in terms of elements is (0.39-0.94) wt%; the dispersity of the active metal component on the catalyst is (69.9 to 100.2) percent. The preparation method of the oxide-loaded heterogeneous catalyst provided by the invention is simple, and expensive phosphorus-containing organic ligands do not need to be used; compared with an existing oxide-loaded heterogeneous catalyst, the prepared oxide-loaded heterogeneous catalyst has the advantages that the dispersity and the loading capacity of active components are higher, and the catalyst has good catalytic performance on olefin hydroformylation, especially high-carbon olefin hydroformylation reaction and has good stability.

Description

Technical Field

[0001] The present invention relates to the field of catalyst technology, and more particularly to an oxide-supported heterogeneous catalyst and a preparation method and application thereof. Background Art

[0002] Hydroformylation is the carbonylation process in which olefins react with synthesis gas (CO / H2) to produce aldehydes. The aldehyde groups generated by hydroformylation can be further converted into imines, amines, hemiacetals, acetals, aminals, carboxyl groups, hydroxyl groups, and other groups. Aldehydes produced by hydroformylation are widely used in the synthesis of fine chemicals such as plasticizers, surfactants, pharmaceuticals, pesticides, and flavorings. The growing demand for aldehydes and alcohols in the chemical industry, coupled with the abundant supply of inexpensive olefins from the petroleum industry, has driven the rapid development of hydroformylation.

[0003] At present, my country's hydroformylation reaction still uses homogeneous catalysts based on rhodium-phosphine complexes. Although this type of catalyst has high activity and selectivity, the subsequent separation and treatment is difficult and costly, especially in the reaction of long-chain olefins. At the same time, the high price of the phosphine-containing ligand itself and its sensitivity to water also restrict the industrial development of the hydroformylation reaction. Compared with homogeneous hydroformylation catalysts, heterogeneous hydroformylation catalysts have the advantage of being easy to separate. In industry, heterogeneous hydroformylation catalysts are often prepared by loading precious metals (such as Pt, Pd and Rh) on the surface of oxides. However, the surface energy of most active metals is greater than the surface energy of solid-phase oxide supports, which makes the active metals easily agglomerated when the oxide support surface is highly loaded, thereby greatly affecting the performance of the obtained heterogeneous catalyst. Therefore, how to ensure that the active metals are efficiently loaded on the oxide support while achieving high dispersion remains the main goal of the current heterogeneous catalytic hydroformylation reaction catalyst design and is also a research hotspot in this field.

[0004] Yin et al. (the 29th Annual Academic Conference of the Chinese Chemical Society, Engineering Science and Technology Series I) rely on electrostatic force to adsorb Rh onto SiO2, Al2O3 and MCM-41 surfaces to prepare heterogeneous catalysts, and a comparative study was conducted on the synthesis of tricyclodecane unsaturated monoaldehyde by dicyclopentadiene hydroformylation. However, this weak electrostatic force between the active metal and the carrier is difficult to overcome the cohesion between the active components, and thus it is impossible to ensure high dispersion during efficient loading. To remedy the above-mentioned shortcomings, Wang et al. (Int. J. Chem. Kinet., 2015, 47: 621-628) use a variety of organophosphine ligands to modify the electrostatic load onto the active metal on the Fe3O4 surface, so as to achieve high load and high dispersion by means of the coordination bond formed between the P atom in the organophosphine ligand and the active metal, thereby improving the performance of the catalyst. However, the catalyst has failed to break away from the limitation of phosphorus ligands, and the preparation process is complicated, and an oxygen-free environment is required, which is costly.

[0005] Therefore, it is very meaningful to provide a method for preparing a heterogeneous catalyst that can improve the loading and dispersion of active metals on oxide supports without using phosphine ligands. Summary of the Invention

[0006] The purpose of the present invention is to provide an oxide-supported heterogeneous catalyst and its preparation method and application, so as to solve the technical problems in the prior art of low loading and easy agglomeration of active metals on oxide supports, resulting in poor catalytic performance, as well as high cost and environmentally unfriendly phosphorus waste caused by the use of phosphine-containing ligands.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] In a first aspect, the present invention provides an oxide-supported heterogeneous catalyst comprising an oxide support and an active metal component covalently supported on the oxide support;

[0009] The active metal component is selected from at least one of Rh, Pb, Ir, and Ru;

[0010] The content of the active metal component in the catalyst is (0.39-0.94) wt% in terms of element;

[0011] The dispersion degree of the active metal component on the catalyst is (69.9-100.2)%.

[0012] In the present invention, the dispersion degree of the active metal component on the catalyst = (n CO ) / (mn M )×100%. Where, n CO is the amount of CO adsorbed by the catalyst (active metal component), m is the number of CO adsorbed by a single active metal component atom in theory (for example, when Rh exists in the form of a single atom, Rh(CO)2 is formed after Rh adsorbs CO, and the amount of CO adsorbed by a single Rh atom (i.e., m) = 2), and n M It is the amount of active metal component supported on the catalyst.

[0013] In the oxide-supported heterogeneous catalyst provided by the present invention, if the active metal component is Rh, the catalyst can be used for the hydroformylation reaction of various olefins, including olefins that are relatively difficult to react, such as isooctene. If the active metal component is Pb, Ir, or Ru, the catalyst is generally more suitable for the hydroformylation reaction of α-olefins, and the catalytic effect for olefins that are relatively difficult to react, such as isooctene, is relatively poor.

[0014] According to some embodiments of the present invention, the content of the active metal component in the catalyst calculated as an element is (0.5 to 0.92) wt%.

[0015] According to some embodiments of the present invention, the content of the active metal component in the catalyst calculated as an element is (0.6 to 0.9) wt%.

[0016] According to some embodiments of the present invention, the dispersion degree of the active metal component on the catalyst is (72-95) wt%.

[0017] According to some embodiments of the present invention, the dispersion degree of the active metal component on the catalyst is (74-90) wt%.

[0018] According to some embodiments of the present invention, the oxide support includes at least one of a metal oxide, a non-metal oxide, a zeolite containing a metal oxide and / or a non-metal oxide, or a molecular sieve.

[0019] According to some embodiments of the present invention, the oxide support comprises Al2O3.

[0020] According to some embodiments of the present invention, the oxide support comprises γ-Al2O3.

[0021] According to some embodiments of the present invention, the particle size of the oxide carrier is ≤100 μm, and the specific surface area is ≥200 m 2 / g.

[0022] According to some embodiments of the present invention, the particle size of the oxide carrier is 30 to 100 μm, and the specific surface area is 200 to 250 m 2 / g.

[0023] According to some embodiments of the present invention, the oxide support is modified by C doping.

[0024] According to some embodiments of the present invention, the C doping modification includes: dispersing the oxide support and the carbon source in water, stirring and mixing, evaporating the water, crushing the obtained solid, and then performing a gas-phase hydrothermal reaction to obtain the C-doped modified oxide support.

[0025] According to some embodiments of the present invention, the stirring and mixing is carried out for 20 to 60 minutes to ensure that the oxide support and the carbon source are evenly mixed.

[0026] In the present invention, various common methods can be used to evaporate the water, such as heating.

[0027] In the present invention, the purpose of pulverizing the obtained solid is to disperse the solid agglomerated during the volatilization of water, so as to make the particles of the C-doped modified oxide support more uniform. Various common solid dispersion operations such as grinding can be used.

[0028] According to some embodiments of the present invention, the conditions of the gas-phase hydrothermal reaction include: reaction temperature of 160-220° C., preferably 180-200° C., and reaction time of 2-20 h, preferably 6-15 h.

[0029] According to some embodiments of the present invention, the C doping modification further comprises: washing and drying the product after the gas phase hydrothermal reaction.

[0030] According to some embodiments of the present invention, the carbon source includes at least one of glucose, mannose, maltose, chitosan, sodium alginate, and cellulose.

[0031] In the present invention, glucose is used as a carbon source to prepare the oxide support for C doping modification. Compared with other types of carbon sources, the catalytic performance of the finally prepared catalyst is better and it is also more advantageous from a cost perspective.

[0032] According to some embodiments of the present invention, the mass ratio of the carbon source to the oxide support is 0.1 to 0.5, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc.

[0033] Preferably, the mass ratio of the carbon source to the oxide carrier is 0.2 to 0.4.

[0034] In a second aspect, the present invention provides a method for preparing an oxide-supported heterogeneous catalyst, comprising: covalently loading an active metal component onto an oxide support with the aid of urea hydrolysis, and then calcining to obtain the oxide-supported heterogeneous catalyst;

[0035] The molar ratio of the urea to the active metal component calculated as a single substance is less than 50;

[0036] The active metal component is selected from at least one of Rh, Pb, Ir, and Ru.

[0037] According to some embodiments of the present invention, the molar ratio of urea to the active metal component calculated as a single substance is less than 45.

[0038] According to some embodiments of the present invention, the molar ratio of urea to the active metal component calculated as a single substance is less than 42.

[0039] According to some embodiments of the present invention, the molar ratio of urea to the active metal component calculated as a single substance is ≤40.

[0040] According to some embodiments of the present invention, the molar ratio of urea to the active metal component calculated as a single substance is 10-40.

[0041] According to some embodiments of the present invention, the molar ratio of urea to the active metal component calculated as a single substance is 20-40.

[0042] According to some embodiments of the present invention, the oxide support includes at least one of a metal oxide, a non-metal oxide, a zeolite containing a metal oxide and / or a non-metal oxide, or a molecular sieve.

[0043] According to some embodiments of the present invention, the oxide support comprises Al2O3.

[0044] According to some embodiments of the present invention, the oxide support comprises γ-Al2O3.

[0045] According to some embodiments of the present invention, the particle size of the oxide carrier is ≤100 μm, and the specific surface area is ≥200 m 2 / g.

[0046] According to some embodiments of the present invention, the particle size of the oxide carrier is 30 to 100 μm, and the specific surface area is 200 to 250 m 2 / g.

[0047] According to some embodiments of the present invention, the oxide support is modified by C doping.

[0048] According to some embodiments of the present invention, the C doping modification includes: dispersing the oxide support and the carbon source in water, stirring and mixing, evaporating the water, crushing the obtained solid, and then performing a gas-phase hydrothermal reaction to obtain the C-doped modified oxide support.

[0049] According to some embodiments of the present invention, the stirring and mixing is carried out for 20 to 60 minutes to ensure that the oxide support and the carbon source are evenly mixed.

[0050] In the present invention, various common methods can be used to evaporate the water, such as heating.

[0051] In the present invention, the purpose of pulverizing the obtained solid is to disperse the solid agglomerated during the volatilization of water, so as to make the particles of the C-doped modified oxide support more uniform. Various common solid dispersion operations such as grinding can be used.

[0052] According to some embodiments of the present invention, the conditions of the gas-phase hydrothermal reaction include: reaction temperature of 160-220° C., preferably 180-200° C., and reaction time of 2-20 h, preferably 6-15 h.

[0053] According to some embodiments of the present invention, the C doping modification further comprises: washing and drying the product after the gas phase hydrothermal reaction.

[0054] According to some embodiments of the present invention, the carbon source includes at least one of glucose, mannose, maltose, chitosan, sodium alginate, and cellulose.

[0055] In the present invention, glucose is used as a carbon source to prepare the oxide support for C doping modification. Compared with other types of carbon sources, the catalytic performance of the finally prepared catalyst is better and it is also more advantageous from a cost perspective.

[0056] According to some embodiments of the present invention, the mass ratio of the carbon source to the oxide support is 0.1 to 0.5, for example, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc.

[0057] Preferably, the mass ratio of the carbon source to the oxide carrier is 0.2 to 0.4.

[0058] According to some embodiments of the present invention, the preparation method comprises the following steps:

[0059] S1. The oxide support is added to the solvent and stirred to obtain a first dispersion;

[0060] S2. The active metal precursor is added to the first dispersion, stirred and mixed to obtain a second dispersion;

[0061] S3. Urea is added to the second dispersion and mixed, and the temperature is raised to 50 to 100 ° C and stirred for reaction;

[0062] S4. After the reaction is completed, the reaction solution is cooled to room temperature and then solid-liquid separation is performed, and the obtained solid is calcined to obtain the oxide-supported heterogeneous catalyst.

[0063] In the preparation method of the oxide-supported heterogeneous catalyst provided by the present invention, the active metal ion M m+ It is combined with the oxide support (YO) in the dispersion through weak electrostatic interaction. After adding urea to the dispersion, urea hydrolyzes to produce NH3 and NH4 + , CO2 and HCO3 - NH3 preferentially reacts with active metal ions M m+ Complexation to form [M(NH3) n ] m+ At the same time, as urea hydrolyzes, the pH of the dispersion increases (from acidic to weakly acidic), causing the hydroxyl groups on the surface of the oxide support to lose protons and convert into oxygen anions YO - . Then, YO - With [M(NH3) n ] m+ Covalent replacement of active metal ions M by YOMm+ The weak electrostatic interaction between the metal and the oxide carrier effectively overcomes the agglomeration force between the metals, thereby ensuring high dispersibility at high loads. In addition, the combined [M(NH3) n ] m+ The residual positive charge can prevent or reduce the free [M(NH3) n ] m+ Aggregation at the same site further improves the dispersion of active metals on the oxide support.

[0064] In the present invention, by firstly making the active metal ion M m+ After being combined with the oxide support through weak electrostatic interaction, urea is added to ensure the active metal ion M m+ While efficiently loading, it can also prevent the hydrolysis of urea from causing some active metal ions M to increase in the dispersion pH. m+ With weak acid anions (such as HCO3 - OH - etc.) first form a precipitate.

[0065] In the present invention, by controlling the amount of urea added, the molar ratio of urea to active metal components (based on simple substance) is less than 50, so that the pH of the dispersion at the end of the reaction can be controlled between 5 and 7, and the active metal ion M m+ It will not form precipitation with weak acid ions in the dispersion.

[0066] According to some embodiments of the present invention, the active metal precursor comprises an active metal salt.

[0067] According to some embodiments of the present invention, the active metal precursor includes chloride salts and nitrate salts of active metals.

[0068] According to some embodiments of the present invention, the active metal precursor includes chloride and nitrate salts of Rh.

[0069] According to some embodiments of the present invention, the active metal precursor includes at least one of RhCl3, RhCl3·xH2O (such as RhCl3·3H2O), Rh(NO3)3, and Rh(NO3)3·2H2O.

[0070] According to some embodiments of the present invention, the concentration of the oxide carrier in the first dispersion is 0.5 to 10 wt%, for example, it can be 0.5 wt%, 0.6 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, etc.

[0071] Preferably, the concentration of the oxide carrier in the first dispersion is 0.8-5 wt %.

[0072] More preferably, the concentration of the oxide carrier in the first dispersion is 1 to 3 wt %.

[0073] According to some embodiments of the present invention, the molar concentration of the active metal precursor in the second dispersion is 0.1 to 10 mmol / L, for example, it can be 0.1 mmol / L, 0.2 mmol / L, 0.3 mmol / L, 0.4 mmol / L, 0.5 mmol / L, 0.6 mmol / L, 0.7 mmol / L, 0.8 mmol / L, 0.9 mmol / L, 1 mmol / L, 1.1 mmol / L, 1.2 mmol / L, 1.3 mmol / L, 1.4 mmol / L, 1.5 mmol / L, 1.6 mmol / L, 1.8 mmol / L, 2 mmol / L, 2.5 mmol / L, 3 mmol / L, 4 mmol / L, 5 mmol / L, 6 mmol / L, 7 mmol / L, 8 mmol / L, 9 mmol / L, 10 mmol / L, etc.

[0074] Preferably, the molar concentration of the active metal precursor in the second dispersion is 0.3 to 3 mmol / L.

[0075] More preferably, the molar concentration of the active metal precursor in the second dispersion is 0.5 to 1.5 mmol / L.

[0076] According to some embodiments of the present invention, the stirring and mixing in step S1 is performed at room temperature for 5 to 15 minutes.

[0077] According to some embodiments of the present invention, the stirring and mixing in step S2 is carried out at a temperature of 25 to 60° C. and for a time of 8 to 12 hours.

[0078] According to some embodiments of the present invention, the temperature of the stirring reaction in step S3 is 80-90°C.

[0079] According to some embodiments of the present invention, the stirring reaction time in step S3 is 2 to 6 hours, preferably 4 to 6 hours.

[0080] According to some embodiments of the present invention, in step S4, drying is performed before calcination; preferably, the drying is vacuum drying.

[0081] According to some embodiments of the present invention, the calcination in step S4 is performed in an inert atmosphere.

[0082] According to some embodiments of the present invention, the inert atmosphere includes at least one of nitrogen and an inert gas.

[0083] According to some embodiments of the present invention, the calcination in step S4 includes performing step-by-step continuous calcination in multiple temperature intervals within the range of room temperature to 600°C.

[0084] According to some embodiments of the present invention, the calcination includes: first heating the temperature to 200°C at a heating rate of 1-10°C / min and holding the temperature for 1-2 hours; then heating the temperature to 300-600°C at a heating rate of 1-2°C / min and holding the temperature for 3-10 hours.

[0085] According to some embodiments of the present invention, after the calcination in step S4 is completed, the material is cooled to room temperature at a rate of 1 to 10° C. / min or a natural cooling rate.

[0086] According to some embodiments of the invention, the solvent comprises water.

[0087] In a third aspect, the present invention provides an oxide-supported heterogeneous catalyst prepared by the preparation method described in the second aspect.

[0088] In a fourth aspect, the present invention provides use of the oxide-supported heterogeneous catalyst described in the first or third aspect in a heterogeneous catalytic reaction, especially an olefin hydroformylation reaction.

[0089] The beneficial effects of the present invention are at least:

[0090] The preparation method of the oxide-supported heterogeneous catalyst provided by the present invention is simple and does not require the use of expensive phosphorus-containing organic ligands. Compared with existing oxide-supported heterogeneous catalysts, the prepared oxide-supported heterogeneous catalyst has higher dispersibility and loading of active components, has good catalytic performance for olefin hydroformylation, especially high-carbon olefin hydroformylation, and has good stability. Therefore, it has broad industrial application prospects in the field of heterogeneous catalysis of olefin hydroformylation. DETAILED DESCRIPTION

[0091] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate this patent in detail and do not limit the scope of protection of the present invention in any way.

[0092] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments, and equipment used in the following examples, etc., are all commercially available or can be obtained by existing methods; the reagent amounts used, unless otherwise specified, are the amounts used in conventional experimental procedures; and the experimental methods described, unless otherwise specified, are all conventional methods.

[0093] In the various embodiments and comparative examples of the present invention, the particle size of the γ-Al2O3 used is 30 to 100 μm, and the specific surface area is 200 to 250 m 2 / g.

[0094] Example 1

[0095] 1 g of γ-Al2O3 was dispersed in 0.1 L of water and stirred at room temperature for 10 min. Then, 1 mL of RhCl3 aqueous solution was added under stirring to make the molar concentration of RhCl3 in the dispersion 1 mmol / L. Subsequently, the mixture was stirred at a constant temperature of 25°C for 10 h. Urea was added to make the molar ratio of urea to Rh (as a single substance) 40. After stirring and reacting at 80°C for 4 h, the above mixture was filtered and separated. The obtained solid was transferred to a vacuum drying oven and vacuum dried at 60°C for 8 h. After being taken out and weighed, a rhodium metal-loaded product was obtained.

[0096] The loaded product was transferred to a tube furnace. After nitrogen was introduced to completely displace the air inside the tube furnace, the temperature was raised to 200°C at a rate of 10°C / min under a nitrogen atmosphere and held at that temperature for 1 hour. Subsequently, the temperature was raised to 450°C at a rate of 1°C / min and held at that temperature for 5 hours. After the heating was turned off, the mixture was allowed to cool naturally to room temperature, yielding the Rh / γ-Al2O3 heterogeneous catalyst.

[0097] Example 2

[0098] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to Example 1, except that the molar concentration of RhCl3 in the dispersion is 0.4 mmol / L.

[0099] Example 3

[0100] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to Example 1, except that the molar concentration of RhCl3 in the dispersion is 0.6 mmol / L.

[0101] Example 4

[0102] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to Example 1, except that the molar concentration of RhCl3 in the dispersion is 0.8 mmol / L.

[0103] Example 5

[0104] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to Example 1, except that the molar concentration of RhCl3 in the dispersion is 1.2 mmol / L.

[0105] Example 6

[0106] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that the molar ratio of urea to Rh (as a single substance) is 10.

[0107] Example 7

[0108] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that the molar ratio of urea to Rh (in terms of elemental mass) is 20.

[0109] Example 8

[0110] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that the molar ratio of urea to Rh (based on elemental mass) is 30.

[0111] Example 9

[0112] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that the molar ratio of urea to Rh (as single substances) is 50.

[0113] Example 10

[0114] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to that of Example 1, except that after adding urea, the reaction was stirred at 50°C for 4 hours.

[0115] Example 11

[0116] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to that of Example 1, except that after adding urea, the reaction was stirred at 60°C for 4 hours.

[0117] Example 12

[0118] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that after adding urea, the reaction is stirred at 70°C for 4 hours.

[0119] Example 13

[0120] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to that of Example 1, except that after adding urea, the reaction was stirred at 90°C for 4 hours.

[0121] Example 14

[0122] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to that of Example 1, except that after adding urea, the reaction was stirred at 80°C for 2 hours.

[0123] Example 15

[0124] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to that of Example 1, except that after adding urea, the reaction was stirred at 80°C for 3 hours.

[0125] Example 16

[0126] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that after adding urea, the reaction is stirred at 80°C for 5 hours.

[0127] Example 17

[0128] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that after adding urea, the reaction is stirred at 80°C for 6 hours.

[0129] Example 18

[0130] The preparation method of Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that γ-Al2O3 is replaced by active Al2O3 (particle size of 30-100 μm, specific surface area of ​​167-192 m 2 / g).

[0131] Example 19

[0132] The preparation method of Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that γ-Al2O3 is replaced by mesoporous Al2O3 (particle size of 30-100 μm, specific surface area of ​​123-145 m 2 / g).

[0133] Example 20

[0134] The preparation method of Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that γ-Al2O3 is replaced by silicon dioxide (particle size of 30-100 μm and specific surface area of ​​200-250 m 2 / g).

[0135] Example 21

[0136] The preparation method of Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that γ-Al2O3 is replaced by SBA-15 (particle size of 30-100 μm, specific surface area of ​​200-250 m 2 / g).

[0137] Example 22

[0138] The preparation method of Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that γ-Al2O3 is replaced by ZSM-35 (particle size of 30-100 μm, specific surface area of ​​200-250 m 2 / g).

[0139] Example 23

[0140] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to that of Example 1, except that the RhCl3 aqueous solution is added to the dispersion and then stirred at a constant temperature of 25°C for 5 hours.

[0141] Example 24

[0142] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to Example 1, with the only difference being that the loaded product was heated to 200°C at a rate of 10°C / min under a nitrogen atmosphere, and then immediately heated to 450°C at a rate of 1°C / min and kept at that temperature for 5 hours without holding the temperature for 1 hour.

[0143] Example 25

[0144] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to that of Example 1, except that the loaded product is directly heated to 450°C at a rate of 10°C / min under a nitrogen atmosphere and then kept at this temperature for 5 hours.

[0145] Example 26

[0146] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to Example 1, with the only difference being that RhCl3 is replaced by Rh(NO3)3.

[0147] Example 27

[0148] The preparation method of Ru / γ-Al2O3 heterogeneous catalyst refers to Example 1, except that RhCl3 is replaced by RuCl3.

[0149] Example 28

[0150] The preparation method of the Rh / C-γ-Al2O3 heterogeneous catalyst refers to Example 1, except that γ-Al2O3 is replaced by an equal mass of C-γ-Al2O3.

[0151] The preparation method of C-γ-Al2O3 includes: dispersing 1g of γ-Al2O3 in 20mL of deionized water, adding 0.3g of glucose, and magnetically stirring for 30 minutes. The resulting mixture is then placed in an oven and dried overnight at 60°C to completely evaporate the water. The resulting solid is lightly ground in a mortar and pestle, then transferred to a 10mL glass bottle. The glass bottle is placed in a 100mL polytetrafluoroethylene-lined reactor, and 5mL of deionized water is added between the glass bottle and the polytetrafluoroethylene liner. The reactor is placed in an oven at 180°C for 6 hours. After the reaction is completed, the reactor is naturally cooled to room temperature. The solid in the glass bottle is washed alternately with water and ethanol and then dried in a vacuum drying oven at 60°C for 8 hours to obtain C-γ-Al2O3.

[0152] Comparative Example 1

[0153] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst refers to Example 1, except that the RhCl3 aqueous solution and urea are added to the dispersion at the same time, stirred at a constant temperature of 25°C for 10 hours, and then stirred at 80°C for 4 hours.

[0154] Comparative Example 2

[0155] The preparation method of the Rh / γ-Al2O3 heterogeneous catalyst is similar to that of Example 1, except that urea is not added during the preparation of the rhodium metal-loaded product.

[0156] Specifically, the preparation method of the rhodium metal-loaded product includes: dispersing 1g of γ-Al2O3 in 0.1L of water, stirring and mixing at room temperature for 10 minutes, adding 1mL of RhCl3 aqueous solution under stirring to make the molar concentration of RhCl3 in the dispersion 1mmol / L, then stirring at a constant temperature of 25°C for 10 hours, and then stirring and reacting at 80°C for 4 hours, filtering and separating the above mixture, transferring the obtained solid to a vacuum drying oven, vacuum drying at 60°C for 8 hours, taking out and weighing to obtain the rhodium metal-loaded product.

[0157] Comparative Example 3

[0158] The preparation method of the Ru / γ-Al2O3 heterogeneous catalyst refers to Example 24, except that no urea is added during the preparation of the ruthenium metal-loaded product.

[0159] Catalyst performance evaluation:

[0160] (1) Catalytic performance evaluation

[0161] Take 200 mg of each catalyst of Example 1-23 or Comparative Example 1-2, mix them with 30 mL of isooctene and 10 mL of toluene, and transfer them into a high-pressure reactor. A CO / H2 mixed gas (the volume ratio of CO and H2 is 1:1) is introduced into the reactor. After replacing the air in the reactor, the pressure is increased to 6 MPa, stirring is started, and the reaction is carried out at a constant temperature of 100°C for 7 hours. The reaction results are shown in Table 1.

[0162] 200 mg of the catalyst of Example 24 or Comparative Example 3 was taken, mixed with 4.5 mL of 1-octene and 1.0 mL of toluene, and then transferred to a high-pressure reactor. A CO / H2 mixed gas (the volume ratio of CO and H2 was 1:1) was introduced into the reactor. After replacing the air in the reactor, the pressure was increased to 10 MPa, stirring was started, and the reaction was carried out at a constant temperature of 150°C for 25 hours. The reaction results are shown in Table 1.

[0163] in:

[0164] (1) Conversion rate 烯烃 =(n 烷烃 +n 醛 +n 醇 ) / (n 烷烃 +n 醛 +n 醇 +n 剩余的烯烃 )×100%.

[0165] (2) Selectivity (醛+醇) =(n 醛 +n 醇 ) / (n 烷烃 +n 醛 +n 醇 )×100%.

[0166] n in the formula 烷烃 、n 醛 、n 醇 、n 剩余的烯烃 They refer to the molar amounts of alkanes, aldehydes, alcohols, and unreacted olefins in the products, respectively.

[0167] (3) Dispersion of active metal component (M) = (n CO ) / (mn M )×100%.

[0168] Where n CO is the amount of CO adsorbed by the active metal component, m is the number of CO adsorbed by a single active metal component atom, and n M It is the amount of active metal component supported on the catalyst.

[0169] The amount of CO adsorbed by the component was measured using a fully automatic chemisorption analyzer. The test conditions were: in a He atmosphere with a flow rate of 50 mL / min, after purging at room temperature for 30 minutes, heating from room temperature to 200°C at a heating rate of 10°C / min and maintaining for 5 minutes; He was replaced with H2 with a flow rate of 50 mL / min, and reduced at 200°C for 1 hour; after cooling to 50°C at a cooling rate of 20°C / min, it was purged with He at a flow rate of 25 mL / min for 5 minutes; a fixed volume of a 10% CO-95% He mixture with a flow rate of 25 mL / min was introduced every 3 minutes, and the unadsorbed CO was detected by a thermal conductivity detector until the adsorption reached saturation; the difference between the introduced CO and the detected CO was calculated, which was the amount of CO adsorbed by the active metal component.

[0170] (4) Active metal component (M) content: measured using an inductively coupled plasma spectrometer (iCAP 6300).

[0171] Table 1

[0172]

[0173]

[0174] Note: M in the table represents active metal components; M content represents the content of active metal components in the catalyst in terms of elements.

[0175] (2) Stability evaluation

[0176] After the catalytic performance evaluation, the catalyst of Example 1 was separated from the reaction mixture, washed, and dried. The catalytic performance evaluation reaction in (1) was repeated. The results of the six-cycle reaction are shown in Table 2.

[0177] Table 2

[0178] Number of cycles Conversion rate (%) (aldehyde + alcohol) selectivity (%) 1 84.4 95.3 2 84.0 95.0 3 84.2 95.4 4 83.8 95.2 5 83.3 95.1 6 82.5 94.8

[0179] As can be seen from Table 2, after 6 cycles of use, the conversion rate and selectivity of the oxide-supported heterogeneous catalyst provided by the present invention only decreased by 2.3% and 0.5%, respectively, and the catalyst has good stability.

[0180] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An oxide-supported heterogeneous catalyst, characterized in that: comprising an oxide support and an active metal component covalently supported on the oxide support; The active metal component is selected from at least one of Rh, Pb, Ir, and Ru; The content of the active metal component in the catalyst calculated as element is (0.39-0.94) wt%, preferably (0.5-0.92) wt%, more preferably (0.6-0.9) wt%; The dispersion degree of the active metal component on the catalyst is (69.9-100.2) wt %, preferably (72-95) wt %, and more preferably (74-90) wt %.

2. The heterogeneous catalyst according to claim 1, characterized in that The oxide support comprises at least one of a metal oxide, a non-metal oxide, a zeolite containing a metal oxide and / or a non-metal oxide, or a molecular sieve; preferably, the oxide support comprises Al2O3; more preferably, the oxide support comprises γ-Al2O3; And / or, the particle size of the oxide carrier is ≤100 μm, and the specific surface area is ≥200 m 2 / g; Preferably, the particle size of the oxide carrier is 30 to 100 μm, and the specific surface area is 200 to 250 m 2 / g.

3. The heterogeneous catalyst according to claim 2, characterized in that The oxide support is modified by C doping; Preferably, the C doping modification comprises: dispersing the oxide support and the carbon source in water, stirring and mixing, evaporating the water, pulverizing the obtained solid, and then performing a gas phase hydrothermal reaction to obtain the C doped and modified oxide support; More preferably, The carbon source includes at least one of glucose, mannose, maltose, chitosan, sodium alginate, and cellulose; And / or, the mass ratio of the carbon source to the oxide support is 0.1 to 0.5, preferably 0.2 to 0.

4.

4. A method for preparing an oxide-supported heterogeneous catalyst, characterized in that: include: The active metal components are covalently loaded on the oxide support with the aid of urea hydrolysis, and then calcined to obtain the oxide-supported heterogeneous catalyst; The molar ratio of urea to the active metal component calculated as a single substance is less than 50, preferably ≤40, more preferably 10 to 40, and even more preferably 20 to 40; The active metal component is selected from at least one of Rh, Pb, Ir, and Ru.

5. The preparation method according to claim 4, characterized in that The oxide support comprises at least one of a metal oxide, a non-metal oxide, a zeolite containing a metal oxide and / or a non-metal oxide, or a molecular sieve; preferably, the oxide support comprises Al2O3; more preferably, the oxide support comprises γ-Al2O3; And / or, the particle size of the oxide carrier is ≤100 μm, and the specific surface area is ≥200 m 2 / g; Preferably, the particle size of the oxide carrier is 30 to 100 μm, and the specific surface area is 200 to 250 m 2 / g.

6. The preparation method according to claim 5, characterized in that The oxide support is modified by C doping; Preferably, the C doping modification comprises: dispersing the oxide support and the carbon source in water, stirring and mixing, evaporating the water, pulverizing the obtained solid, and then performing a gas phase hydrothermal reaction to obtain the C doped and modified oxide support; More preferably, The carbon source includes at least one of glucose, mannose, maltose, chitosan, sodium alginate, and cellulose; And / or, the mass ratio of the carbon source to the oxide support is 0.1 to 0.5, preferably 0.2 to 0.

4.

7. The preparation method according to any one of claims 4 to 6, characterized in that The steps include: S1. The oxide support is added to the solvent and stirred to obtain a first dispersion; S2. The active metal precursor is added to the first dispersion, stirred and mixed to obtain a second dispersion; S3. Urea is added to the second dispersion and mixed, and the temperature is raised to 50 to 100 ° C and stirred for reaction; S4. After the reaction is completed, the reaction solution is cooled to room temperature and then solid-liquid separation is performed, and the obtained solid is calcined to obtain the oxide-supported heterogeneous catalyst.

8. The preparation method according to claim 7, characterized in that The active metal precursor includes an active metal salt; Preferably, the active metal precursor includes chloride and nitrate salts of active metals; More preferably, the active metal precursor includes chloride and nitrate salts of Rh; More preferably, the active metal precursor includes RhCl3, RhCl 3· At least one of xH2O, Rh(NO3)3, and Rh(NO3)3·2H2O.

9. The preparation method according to claim 7 or 8, characterized in that The concentration of the oxide carrier in the first dispersion is 0.5 to 10 wt %; And / or, the molar concentration of the active metal precursor in the second dispersion is 0.1 to 10 mmol / L.

10. The preparation method according to any one of claims 7 to 9, characterized in that: The stirring and mixing in step S2 is performed at a temperature of 25 to 60° C. and for a time of 8 to 12 hours; And / or, the stirring reaction temperature in step S3 is 80-90°C; And / or, the stirring reaction time in step S3 is 2 to 6 hours.

11. The preparation method according to any one of claims 7 to 10, characterized in that: The calcination in step S4 is carried out in an inert atmosphere; And / or, the calcination in step S4 includes performing step-by-step continuous calcination in multiple temperature intervals within the range of room temperature to 600° C.; preferably, the calcination includes: first heating to 200° C. at a heating rate of 1 to 10° C. / min, and holding the temperature for 1 to 2 hours; then heating to 300 to 600° C. at a heating rate of 1 to 2° C. / min, and holding the temperature for 3 to 10 hours; And / or, after the calcination in step S4 is completed, the mixture is cooled to room temperature at a rate of 1 to 10° C. / min or a natural cooling rate.

12. An oxide-supported heterogeneous catalyst prepared by the preparation method according to any one of claims 4 to 11.

13. Use of the oxide-supported heterogeneous catalyst according to any one of claims 1 to 3 or 12 in heterogeneous catalytic reactions, especially olefin hydroformylation reactions.

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