A catalyst suitable for the production of methyl acrylate, its preparation and use

Abstract

The present invention discloses a catalyst suitable for producing methacrylic acid, its preparation method and application. The catalyst comprises an active component as shown in the general formula PMo a V b In c Ir d X e Z f O g The catalyst of the present invention has the advantages of high conversion rate of methacrolein and low catalyst abrasion in the reaction of producing methacrylic acid.

Description

Technical Field

[0001] This invention relates to the field of methacrylic acid preparation, and more specifically to a catalyst suitable for the production of methacrylic acid, its preparation method, and its application. Background Technology

[0002] Methyl methacrylate (MMA) is a crucial chemical intermediate widely used in the construction industry, transportation, household appliance materials, container manufacturing, optical lens production, and resin and plastic modifier production. It can also be used to prepare coatings, adhesives, waterproofing agents, and rubber modifiers. Currently, the main industrial process for producing MMA is the ACH (acetone-cyanohydrin process), which uses acetone and hydrogen cyanide as raw materials and requires the addition of sulfuric acid. During the reaction, sulfuric acid is highly corrosive to equipment, hydrogen cyanide is extremely toxic, the byproduct ammonium bisulfate is difficult to separate, and the overall atom utilization rate is low. Therefore, research and development of new processes have been spurred. The route of producing methacrolein through isobutylene oxidation, followed by further oxidation to methacrylic acid, and then reacting with CH3OH to produce MMA has become a research hotspot both domestically and internationally. This method significantly improves the environmental friendliness of the reaction raw materials. A crucial step in this route is the development of selective oxidation of methacrolein to methacrylic acid; therefore, the development of highly active, long-life catalysts is of great significance.

[0003] Catalysts for the selective oxidation of methacrolein to methacrylic acid have been reported in the literature, with most studies focusing on heteropolyacids or salts with P, Mo, and V as the main components. These catalysts are based on the Keggin structure, and the addition of other modifying elements, such as alkali metals, can improve stability and help suppress excessive oxidation of methacrylic acid. Transition metal doping also significantly affects catalyst performance due to its good redox properties. CN1483014A discloses a catalyst for the oxidation of methacrolein to methacrylic acid and its application. However, this catalyst suffers from drawbacks such as poor thermal stability, poor mechanical strength, low methacrolein reactivity, and poor selectivity for methacrylic acid.

[0004] Existing catalysts for the production of methacrylic acid suffer from problems to varying degrees, such as low raw material conversion rate, poor product selectivity, and high catalyst wear rate. Further research and development of catalysts suitable for the production of methacrylic acid and improvement of catalyst performance are of great significance. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a catalyst suitable for the production of methacrylic acid, its preparation method, and its application. The catalyst of this invention, when used in the production of methacrylic acid, has the advantages of high methacrolein conversion rate and low catalyst wear.

[0006] A first aspect of the present invention provides a catalyst suitable for the production of methacrylic acid, the catalyst comprising an active component represented by general formula (1):

[0007] PMo a V b In c Ir d X e Z f O g Equation (1)

[0008] In formula (1), X includes one or more selected from transition metals;

[0009] Z includes one or more selected from alkali metals and alkaline earth metals;

[0010] The value of 'a' ranges from 2.0 to 12.0.

[0011] b takes values ​​from 0.1 to 1.2;

[0012] c takes values ​​from 0.1 to 1.5;

[0013] The value of d ranges from 0.1 to 1.7;

[0014] e ranges from 0.1 to 1.0;

[0015] f takes values ​​from 0.1 to 1.2;

[0016] g represents the number of moles of oxygen atoms required to satisfy the valence of other elements in the active component.

[0017] According to the present invention, X includes one or more of Sc, Ti, Y, Zr, Nb, Hf, Ta, Cr, V, Mn, Tc, W, Re, Fe, Ru, Os, Co, Rh, Ni, Pd, Pt, Cu, Ag, Au, Zn and Cd.

[0018] According to the present invention, Z includes one or more of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr and Ba.

[0019] According to the present invention, the value of a is 8.0 to 12.0.

[0020] According to the present invention, b takes the value of 0.6 to 1.0.

[0021] According to the present invention, c takes the value of 0.45 to 1.4.

[0022] According to the present invention, d takes the value of 0.45 to 1.4.

[0023] According to the present invention, e takes the value of 0.6 to 1.0.

[0024] According to the present invention, f takes a value of 0.6 to 1.0.

[0025] According to the present invention, a, b, c, d, e and f represent the molar ratios of Mo, V, In, Ir, X and Z to P, respectively.

[0026] According to the present invention, the ratio of c to d is (0.1 to 5):1, preferably (0.35 to 3.0):1, and more preferably (1 to 3):1.

[0027] According to the present invention, the catalyst exhibits two reduction peaks in the temperature-programmed reduction (TPR) spectrum, preferably two reduction peaks with different relative intensities.

[0028] According to the present invention, the position of the main reduction peak is 400℃~570℃, preferably 400℃~510℃; the position of the secondary reduction peak is 600℃~700℃, preferably 600℃~660℃.

[0029] According to the present invention, the positions of the main reduction peak and the secondary reduction peak differ by 120°C to 180°C.

[0030] According to the present invention, the ratio of the peak area of ​​the main reduction peak to the peak area of ​​the secondary reduction peak is (2-20):1.

[0031] According to the present invention, the catalyst further includes a support. The support includes one or more of lithium oxide, magnesium oxide, aluminum oxide, zirconium dioxide, silicon dioxide, titanium dioxide, vanadium dioxide, diatomaceous earth, kaolin, and pumice.

[0032] According to the present invention, in the catalyst, the content of the support is 10 wt% to 50 wt%; and the content of the active component is 50 wt% to 90 wt%.

[0033] According to the present invention, the carrier may be a powdered solid particle, preferably with a particle size of 0.1 mm to 20 mm, more preferably 1 mm to 10 mm.

[0034] According to the present invention, the catalyst surface has a cluster structure, preferably the cluster structure accounts for 30% to 70% of the surface area.

[0035] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst, comprising the following steps:

[0036] (1) Mix the P source, Mo source, V source, In source, Ir source, X source and Z source to obtain a mixed solution;

[0037] (2) The mixture obtained in step (1) is mixed with the support to obtain the catalyst precursor;

[0038] (3) The catalyst precursor obtained in step (2) is dried and calcined to obtain the catalyst.

[0039] According to the present invention, preferably, the mixing temperature in step (1) is 20°C to 90°C, and more preferably 50°C to 80°C.

[0040] According to the present invention, preferably, the pH value of the mixture in step (1) is adjusted to 0.5 to 7, more preferably 1 to 6, and more preferably 2 to 5.

[0041] According to the present invention, the pH adjuster for adjusting pH includes one or more selected from nitric acid, oxalic acid, formic acid, acetic acid, gluconic acid, acrylic acid, and citric acid.

[0042] According to the present invention, the P source in step (1) comprises a phosphorus-containing compound, preferably phosphoric acid. The Mo source comprises a molybdenum-containing compound, preferably ammonium molybdate. The V source comprises a vanadium-containing compound, preferably ammonium metavanadate. The In source comprises an indium-containing compound, preferably indium nitrate. The Ir source comprises an iridium-containing compound, preferably iridium trinitrate. The X source comprises a transition metal-containing compound, preferably a transition metal salt. The Z source comprises at least one of an alkaline earth metal compound and an alkali metal compound, preferably a salt containing the element Z.

[0043] According to the present invention, the drying temperature in step (3) is 60°C to 150°C. The drying time is 1 hour to 48 hours.

[0044] According to the present invention, the calcination temperature in step (3) is 300℃~500℃. The calcination time is 1h~48h.

[0045] According to the present invention, the roasting atmosphere in step (3) is an oxygen-containing atmosphere. Further, the volume content of oxygen in the oxygen-containing atmosphere is 10-40%. Even further, the roasting atmosphere is air.

[0046] According to the present invention, the catalyst prepared by the preparation method has a cluster structure on its surface, preferably the cluster structure accounts for 30% to 70% of the surface area.

[0047] The third aspect of the present invention provides the application of the above-described catalyst or the catalyst prepared by the above-described method in the production of methacrylic acid.

[0048] According to the present invention, the reaction is carried out using methacrolein and oxygen-containing gas as raw materials, and the raw materials react with a catalyst to obtain methacrylic acid.

[0049] According to the present invention, a diluting gaseous material may also be added to the feed gas; the presence of the diluting gaseous material can make the reaction more stable and controllable.

[0050] According to the present invention, the dilutive gaseous material is water. The water exists in the form of water vapor.

[0051] According to the present invention, the oxygen-containing gas is at least one of air, pure oxygen, and oxygen-enriched gas, preferably air.

[0052] According to the present invention, the reaction temperature is 100°C to 500°C.

[0053] According to the present invention, in the raw material gas, the volume ratio of methacrolein to oxygen-containing gas is 1:(10-30).

[0054] According to the present invention, the volume ratio of the added diluent gaseous material to methacrolein is (1-8):1.

[0055] According to the present invention, the total volumetric space velocity of the feed gas is 1000-4000 h⁻¹. -1 .

[0056] Compared with the prior art, the main beneficial effects achieved by the present invention are as follows:

[0057] (1) In this invention, the catalyst comprises the general formula PMo a V b In c Ir d X e Z f O g The active component shown includes X, which comprises one or more selected from transition metals; and Z, which comprises one or more selected from alkali metals and alkaline earth metals. Preferably, a specific ratio of In and Ir is added to the active component of the catalyst. The synergistic effect of In and Ir increases the area of ​​the main reduction peak of the catalyst and decreases the reduction temperature, thus giving the catalyst stronger oxidation ability and making it easier to be reduced to a lower oxidation state, which is beneficial to improving catalyst performance. In and Ir have a synergistic effect on improving the catalytic performance of the catalyst in the reaction of methacrylic acid, especially on the conversion rate of methacrolein and the catalyst attrition rate.

[0058] The catalyst of this invention has a cluster structure with a high surface area ratio, which is beneficial to the presence of more active centers in the selective oxidation reaction, thereby promoting the adsorption of the reactant methacrolein on the catalyst surface and the desorption of the reaction product.

[0059] (2) In the preparation method of the catalyst, a specific ratio of In source and Ir source is added to the active component source. The synergistic effect of In and Ir improves the catalytic performance of the catalyst in the reaction of methacrylic acid, especially the synergistic effect on the conversion rate of methacrolein and the wear rate of the catalyst.

[0060] (3) In this invention, the catalyst is suitable for the production of methacrylic acid. When the catalyst of this invention is used in the production of acrylic acid, the reaction results show that the conversion rate of methacrolein can be as high as 86% or more, and the attenuation rate can be less than 1.0%. Attached Figure Description

[0061] Figure 1 This is an SEM image of the catalyst prepared in Example 1.

[0062] Figure 2 This is a SEM image of the catalyst prepared in Comparative Example 1.

[0063] Figure 3 This is a TPR diagram of the catalysts prepared in Comparative Example 1 and Example 1. Detailed Implementation

[0064] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the following description.

[0065] In this invention, the TPR testing instrument is an AutoChem II 2950, ​​manufactured by Micron Instruments, Inc., USA. The testing method involves pretreating a 50mg sample in an O2 and Ar atmosphere (50ml / min, 5vol% O2) at 450℃ for 30 minutes. After cooling to room temperature, an H2 and Ar atmosphere (50ml / min, 5vol% H2) is introduced for 15 minutes, and then the temperature is increased to 800℃ at a rate of 10℃ / min. The test parameter is the curve of relative intensity changing with reduction temperature.

[0066] In this invention, the SEM instrument model is ZEISS Merlin, and the testing method is to observe the morphology of the catalyst surface under a high voltage of 20.0kV and a scale of 200nm. The test parameter is the catalyst surface profile.

[0067] In this invention, the wear rate testing instrument is model CWXJ-88. The testing method is as follows: 100g of catalyst is placed in the wear rate testing instrument drum and rotated for 30 minutes. The sample is then sieved through a 20-mesh sieve, and the mass m of the broken catalyst is measured. The wear rate is m / 100*100%. The test parameter is the wear rate.

[0068] In this invention, the method for evaluating the selectivity of the catalyst is as follows:

[0069] Reactor: Fixed-bed microreactor, inner diameter 10 mm, reactor length 400 mm;

[0070] Catalyst loading: 2 grams;

[0071] Reaction temperature: 310℃;

[0072] Reaction time: 4 hours;

[0073] Raw material volume ratio: Methacrolein: Air: Water vapor = 1:20:4;

[0074] Total volumetric space velocity of feed gas: 2500 h -1 .

[0075] In this invention, the room temperature in each embodiment is 20°C.

[0076] In this invention, the subscript "g" of element Q in each embodiment and Table 1 indicates the number of moles of oxygen atoms required to satisfy the valence of other elements in the active component.

[0077] Example 1

[0078] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.09 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.09 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 0.9 Ir 0.9 Co 0.8 Rb 0.8 O g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 4.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0079] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0080] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0081] PMo 10 VIn 0.9 Ir 0.9 Co 0.8 Rb 0.8 O g (33wt%) + TiO2 (67wt%)

[0082] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0083] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0084] The prepared catalyst was subjected to SEM analysis, and the results are shown in the figure. Figure 1 The cluster structure accounts for 55% of the surface area.

[0085] The TPR diagram of the catalyst in this example is shown below. Figure 3 .

[0086] Example 2

[0087] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.047 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.133 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 0.47 Ir 1.33 Co 0.8 Rb 0.8 O g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 4.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0088] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0089] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0090] PMo 10 VIn 0.47 Ir 1.33 Co 0.8 Rb 0.8 O g (33w%) + TiO2 (67w%)

[0091] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0092] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0093] Example 3

[0094] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.135 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.045 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 1.35 Ir 0.45 Co 0.8 Rb 0.8 O g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 4.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0095] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0096] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0097] PMo 10 VIn 1.35 Ir 0.45 Co 0.8 Rb 0.8 O g (33w%) + TiO2 (67w%)

[0098] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0099] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0100] Example 4

[0101] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 0.8 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.09 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.09 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.09 mol of Co, and rubidium nitrate (RbNO3) containing 0.1 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C until the mixture solution contains the active component PMo8VIn. 0.9 Ir 0.9 Co 0.9 RbO g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 1.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0102] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0103] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0104] PMo8VIn 0.9 Ir 0.9 Co 0.9 RbO g (33w%) + TiO2 (67w%)

[0105] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0106] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0107] Example 5

[0108] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.07 mol of V, indium nitrate (In(NO3)3) containing 0.09 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.09 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.06 mol of Co, and rubidium nitrate (RbNO3) containing 0.06 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 V 0.7 In 0.9 Ir 0.9 Co 0.6 Rb 0.6 O g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 6.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0109] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0110] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0111] PMo 10 V 0.7 In 0.9 Ir 0.9 Co 0.6 Rb 0.6 O g (33w%) + TiO2 (67w%)

[0112] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0113] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0114] Example 6

[0115] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.016 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.164 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 0.16 Ir 1.64 Co 0.8 Rb 0.8 O g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 4.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0116] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0117] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0118] PMo 10 VIn 0.16 Ir 1.64 Co 0.8 Rb 0.8 O g (33w%) + TiO2 (67w%)

[0119] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0120] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0121] Example 7

[0122] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.15 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.03 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 1.5 Ir 0.3 Co 0.8 Rb 0.8 O g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 4.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0123] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0124] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0125] PMo 10 VIn 1.5 Ir 0.3 Co 0.8 Rb 0.8 O g (33w%) + TiO2 (67w%)

[0126] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0127] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0128] Example 8

[0129] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.09 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.09 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 0.9 Ir 0.9 Co 0.8 Rb 0.8 O g The concentration is 0.5 g / g, and 0.1 mol / L nitric acid is used. Adjust the pH value to 0.5. The active component mixture I was obtained.

[0130] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0131] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0132] PMo 10 VIn 0.9 Ir 0.9 Co 0.8 Rb 0.8 O g (33w%) + TiO2 (67w%)

[0133] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0134] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0135] Example 9

[0136] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.09 mol of In, iridium trinitrate (HNO3.1 / 3Ir) containing 0.09 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 0.9 Ir 0.9 Co 0.8 Rb 0.8 O g The concentration of the active ingredient was 0.5 g / g. 0.1 mol / L ammonia water was used to adjust the pH value to 7.0 to obtain active ingredient mixture I.

[0137] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0138] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0139] PMo 10 VIn 0.9 Ir 0.9 Co 0.8 Rb 0.8 O g (33w%) + TiO2 (67w%)

[0140] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0141] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0142] Comparative Example 1

[0143] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, iridium trinitrate (HNO3.1 / 3Ir) containing 0.09 mol of Ir, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 0.9 Ir 0.9 Co 0.8 Rb 0.8 O g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 4.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0144] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0145] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0146] PMo 10 VIr 0.9 Co 0.8 Rb 0.8 O g (33wt%) + TiO2 (67wt%)

[0147] The prepared catalyst was evaluated, and the results are shown in Table 1.

[0148] The prepared catalyst was subjected to TPR testing, and the test results are shown in Table 2.

[0149] The TPR diagram of the catalyst in this example is shown below. Figure 3 The prepared catalyst was subjected to SEM analysis, and the results are shown in the figure. Figure 2 The cluster structure accounts for 15% of the surface area.

[0150] Comparative Example 2

[0151] Step 1: Add phosphoric acid (H3PO4) containing 0.1 mol of phosphorus to a three-necked flask. Then add ammonium molybdate ((NH4)2MoO4) containing 1.0 mol of Mo, ammonium metavanadate (NH4VO3) containing 0.1 mol of V, indium nitrate (In(NO3)3) containing 0.09 mol of In, cobalt nitrate (Co(NO3)2) containing 0.08 mol of Co, and rubidium nitrate (RbNO3) containing 0.08 mol of Rb. Dissolve the mixture at 80°C, and continue stirring at 80°C to evaporate the mixture until the solution contains the active component PMo. 10 VIn 0.9 Ir 0.9 Co 0.8 Rb 0.8 O g The concentration of the active ingredient was 0.5 g / g. The pH was adjusted to 4.0 using 0.1 mol / L nitric acid to obtain active ingredient mixture I.

[0152] Step 2: Take 200g of the above active component mixture I, cool it to room temperature, and mix it with spherical titanium dioxide support particles with a diameter of 5mm to obtain the catalyst precursor.

[0153] Step 3: The catalyst precursor was dried in an oven at 80°C for 12 hours, and then calcined in a muffle furnace at 360°C in air for 10 hours to obtain a catalyst with the following composition:

[0154] PMo 10 VIn 0.9 Co 0.8 Rb 0.8 O g (33wt%) + TiO2 (67wt%)

[0155] The prepared catalyst was evaluated, and the results are shown in Table 1. The prepared catalyst underwent TPR testing, and the results are shown in Table 2.

[0156] Table 1 Catalyst Evaluation Effect

[0157]

[0158] Table 2. TPR test results for each catalyst example.

[0159]

[0160] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on 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 terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A catalyst suitable for the production of methacrylic acid, said catalyst comprising an active component represented by general formula (1): PMo a V b In c Ir d X e Z f O g Formula (1) In formula (1), X includes one or more selected from transition metals; Z includes one or more selected from alkali metals and alkaline earth metals; The value of 'a' ranges from 2.0 to 12.

0. b takes values ​​from 0.1 to 1.2; c takes values ​​from 0.1 to 1.5; The value of d ranges from 0.1 to 1.7; e takes values ​​from 0.1 to 1.0; f takes values ​​from 0.1 to 1.2; g represents the number of moles of oxygen atoms required to satisfy the valence of other elements in the active component. The ratio of c to d is (0.1~5):1; The catalyst exhibits two reduction peaks with different relative intensities in the temperature-programmed reduction (TPR) spectrum.

2. The catalyst according to claim 1, characterized in that, c takes values ​​from 0.45 to 1.4; and / or d takes values ​​from 0.45 to 1.

4.

3. The catalyst according to claim 1, characterized in that, The ratio of c to d is (0.35~3.0):

1.

4. The catalyst according to claim 1, characterized in that, The ratio of c to d is (1~3):

1.

5. The catalyst according to claim 1, characterized in that, X includes one or more of Sc, Ti, Y, Zr, Nb, Hf, Ta, Cr, V, Mn, Tc, W, Re, Fe, Ru, Os, Co, Rh, Ni, Pd, Pt, Cu, Ag, Au, Zn, and Cd; And / or, the Z includes one or more of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr and Ba.

6. The catalyst according to claim 1, characterized in that, The main reduction peak is located at 400℃~570℃; the secondary reduction peak is located at 600℃~700℃.

7. The catalyst according to claim 6, characterized in that, The main reduction peak is located at 400℃~510℃; the secondary reduction peak is located at 600℃~660℃.

8. The catalyst according to claim 6, characterized in that, The positions of the main reduction peak and the secondary reduction peak differ by 120℃~180℃.

9. The catalyst according to claim 6, characterized in that, The ratio of the peak area of ​​the main reduction peak to the peak area of ​​the secondary reduction peak is (2~20):

1.

10. The catalyst according to claim 1, characterized in that, The catalyst further includes a support; the support includes one or more of lithium oxide, magnesium oxide, aluminum oxide, zirconium dioxide, silicon dioxide, titanium dioxide, vanadium dioxide, diatomite, kaolin, and pumice.

11. The catalyst according to claim 10, characterized in that, In the catalyst, the content of the support is 10wt%~50wt%, and the content of the active component is 50wt%~90wt%.

12. A method for preparing the catalyst according to any one of claims 1 to 11, comprising the following steps: (1) Mix the P source, Mo source, V source, In source, Ir source, X source and Z source to obtain a mixed solution; (2) The mixture obtained in step (1) is mixed with the support to obtain the catalyst precursor; (3) The catalyst precursor obtained in step (2) is dried and calcined to obtain the catalyst.

13. The preparation method according to claim 12, characterized in that, In step (1), the pH of the mixture is adjusted to 0.5~7.

14. The preparation method according to claim 13, characterized in that, In step (1), the pH of the mixture is adjusted to 1~6.

15. The preparation method according to claim 14, characterized in that, In step (1), the pH of the mixture is adjusted to 2-5.

16. The preparation method according to claim 12, characterized in that, In step (3), the drying temperature is 60℃~150℃ and the drying time is 1h~48h; And / or, the roasting temperature in step (3) is 300℃~500℃ and the roasting time is 1h~48h.

17. The preparation method according to claim 16, characterized in that, In step (3), the roasting atmosphere is an oxygen-containing atmosphere.

18. The preparation method according to claim 17, characterized in that, The volume content of oxygen in the oxygen-containing atmosphere described in step (3) is 10~40%.

19. The preparation method according to claim 18, characterized in that, In step (3), the roasting atmosphere is air.

20. The use of the catalyst according to any one of claims 1 to 11 or the catalyst prepared by the preparation method according to any one of claims 12 to 19 in the production of methacrylic acid.

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