A propylene oxidation catalyst, its preparation and use

Abstract

The present application relates to a kind of propylene oxidation catalyst, the catalyst includes carrier and active metal oxide component, the active metal oxide is the following component:Mo, Bi, Fe, X, Y, Z and O, wherein, the component X is selected from at least one of Ag, Zr, Ni, Mn, Mg;The component Y is selected from at least one of K, Cs, Rb, Li, Na;The component Z is selected from at least one of Co, Ce, La;Preferably, the molar ratio of the component Mo, Bi, Fe, X, Y and Z is 12:(0.3-4.2):(0.4-4.0):(0.6-9.0):(0.1-0.8):(0.5-5.8);And / or, the molar number of the component O is the total number of oxygen atom required to meet the valence of other components.This application also provides a kind of propylene oxidation catalyst preparation method and application.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, and in particular relates to a propylene oxidation catalyst, its preparation method, and its application. Background Technology

[0002] The selective oxidation of olefins to prepare unsaturated aldehydes and unsaturated acids is an important chemical process. The production of unsaturated aldehydes uses a catalyst whose active components contain Mo and Bi.

[0003] Chinese patent CN107282056A provides a catalyst for the oxidative synthesis of acrolein and acrylic acid from propylene. It employs a support with a large number of macroporous structures and a catalyst with highly dispersed active components, which has significant benefits for improving the propylene oxidation reaction and heat dissipation of the catalyst bed.

[0004] Chinese patent CN114650880A provides a method for producing a multiphase mixed oxide catalyst, which comprises at least one active phase based on bismuth molybdate and a co-catalyst based on iron molybdate and at least one of cobalt and nickel. The catalyst of this type is produced by replacing the above-mentioned hydrothermal reaction with a microwave-assisted hydrothermal reaction, and has high reactivity.

[0005] To improve the conversion and selectivity of olefin oxidation reactions, existing technologies mainly focus on improvements to catalyst structure, catalyst composition, and reaction methods. However, there are no existing technologies that address improving the lattice oxygen migration rate within the catalyst. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a propylene oxidation catalyst, its preparation method, and its application.

[0007] Therefore, in a first aspect, the present invention provides a propylene oxidation catalyst, the catalyst comprising a support and an active metal oxide component, wherein the active metal oxide comprises the following components: Mo, Bi, Fe, X, Y, Z and O, wherein component X is selected from at least one of Ag, Zr, Ni, Mn and Mg; component Y is selected from at least one of K, Cs, Rb, Li and Na; and component Z is selected from at least one of Co, Ce and La.

[0008] In some embodiments of the present invention, the molar ratio of the components Mo, Bi, Fe, X, Y and Z is 12:(0.3-4.2):(0.4-4.0):(0.6-9.0):(0.1-0.8):(0.5-5.8); and / or, the number of moles of the component O is the total number of oxygen atoms required to satisfy the valence of the other components.

[0009] In some embodiments of the present invention, the molar ratio of component Z to component Fe in the active metal oxide component is 4.0-10.0; preferably 5.5-8.2.

[0010] In some embodiments of the present invention, the active metal oxide component is represented by the following general formula: Mo 12 Bi a Fe b X c Y d Z e O χ X is selected from at least one of Ag, Zr, Ni, Mn, and Mg; Y is selected from at least one of K, Cs, Rb, Li, and Na; and Z is selected from at least one of Co, Ce, and La.

[0011] In some embodiments of the present invention, in the general formula of the active metal oxide component, the value of a ranges from 0.3 to 4.2; the value of b ranges from 0.4 to 4.0; the value of c ranges from 0.6 to 9.0; the value of d ranges from 0.1 to 0.8; the value of e ranges from 0.5 to 5.8; and x is the total number of oxygen atoms required to satisfy the valence of other elements.

[0012] In some embodiments of the present invention, the value of e / b ranges from 4.0 to 10.0; preferably from 5.5 to 8.2.

[0013] In some embodiments of the present invention, the catalyst is used in propylene pulse tests, and when the pulse interval is greater than 60 seconds, the rate of decrease in propylene conversion is less than 10% in the first three propylene pulse tests. If the rate of decrease in propylene conversion is less than 10% in the first three propylene pulse tests, it indicates that the catalyst has a relatively fast lattice oxygen migration rate.

[0014] In the oxidation reaction of propylene with the catalyst, surface and shallow active lattice oxygen is consumed, leading to a decrease in catalyst activity. Bulk lattice oxygen migrates to the shallow layer of the catalyst to restore activity. The migration rate of lattice oxygen can be represented by the change in propylene conversion rate during continuous propylene pulse tests. The propylene conversion rate is calculated based on the amount of unreacted propylene in the tail gas after the pulse test and the amount of propylene in the feed gas after the pulse test. In this invention, the propylene conversion rate decreases by less than 10% in the first three propylene pulse tests.

[0015] In some embodiments of the present invention, the support is selected from at least one of SiO2, Al2O3 and TiO2.

[0016] In some embodiments of the present invention, the specific surface area of ​​the carrier is 70-120 m². 2 / g; and / or, the pore volume of the carrier is 0.06-0.11 mL / g.

[0017] In some embodiments of the present invention, the content of the support is 5%-20% by weight based on the total weight of the catalyst; and / or the content of the active metal oxide component is 80%-95% by weight.

[0018] The second aspect of the present invention provides a method for preparing a catalyst as described in the first aspect, the method comprising: mixing an active metal oxide precursor with a support precursor, and aging and calcining the mixture to obtain the catalyst.

[0019] In some embodiments of the present invention, the roasting atmosphere is air.

[0020] In some embodiments of the present invention, the oxygen content of the air is less than 30%, preferably less than 20%.

[0021] In some embodiments of the present invention, the air flow rate is 10-18 mL / (min·gcat), preferably 12-17 mL / (min·gcat).

[0022] In this invention, the air flow unit "mL / (min·gcat)" refers to the air flow rate of milliliters per minute relative to one gram of catalyst.

[0023] In some embodiments of the present invention, the roasting includes two stages of roasting.

[0024] In some embodiments of the present invention, the method includes the following specific steps:

[0025] S1, the active metal oxide precursor is mixed with the carrier precursor to obtain a slurry;

[0026] S2, the obtained slurry is aged, dried and pulverized to obtain the catalyst precursor;

[0027] S3, the obtained catalyst precursor is subjected to two-stage calcination to obtain the catalyst;

[0028] In some embodiments of the present invention, the material in which the active metal oxide component of the active metal oxide precursor is Fe is added separately at the end for mixing.

[0029] In some embodiments of the present invention, the conditions for the two-stage roasting include: the roasting temperature of the first stage is 300-400℃, preferably 320-390℃; and the roasting time is 60-90 min.

[0030] In some embodiments of the present invention, the conditions for the two-stage roasting include: the roasting temperature of the second stage is 450-550℃, preferably 460-520℃; and the roasting time is 100-450 min, preferably 120-380 min.

[0031] In some embodiments of the present invention, the aging conditions include: an aging temperature of 60-80°C, for example 70°C; and an aging time of 8-50 hours, for example 24 hours.

[0032] In some embodiments of the present invention, the drying conditions include: a drying temperature of 120-150°C, for example 135°C; and a drying time of 16-30 hours, for example 20 hours.

[0033] In some embodiments of the present invention, the active metal oxide precursor comprises a soluble salt containing a metal element represented by a general formula, obtained by compounding, wherein the general formula is Mo. 12 Bi a Fe b X c Y d Z e O χ X is selected from at least one of Ag, Zr, Ni, Mn, and Mg; Y is selected from at least one of K, Cs, Rb, Li, and Na; and Z is selected from at least one of Co, Ce, and La.

[0034] In some embodiments of the present invention, the carrier precursor includes, but is not limited to, silicon dioxide, silica sol, or titanium dioxide.

[0035] In some embodiments of the present invention, the amount of the soluble salt of the metal element represented by the general formula and the amount of the support precursor in the active metal oxide precursor are calculated by the general formula, wherein the general formula is Mo. 12 Bi a Fe b X c Y d Z e O χ Where X is selected from at least one of Ag, Zr, Ni, Mn, and Mg; Y is selected from at least one of K, Cs, Rb, Li, and Na; Z is selected from at least one of Co, Ce, and La; the value of a ranges from 0.3 to 4.2; the value of b ranges from 0.4 to 4.0; the value of c ranges from 0.6 to 9.0; the value of d ranges from 0.1 to 0.8; the value of e ranges from 0.5 to 5.8; and χ is the total number of oxygen atoms required to satisfy the valence of other elements.

[0036] In some embodiments of the present invention, the soluble salt of the metal element represented by the general formula includes the nitrate of the metal element represented by the general formula.

[0037] A third aspect of the present invention provides a propylene oxidation catalyst prepared by the preparation method described in the second aspect.

[0038] In some embodiments of the present invention, the catalyst comprises a support and an active metal oxide component, the active metal oxide component being represented by the following general formula: Mo 12 Bi a Fe b X c Y d Z e O χ X is selected from at least one of Ag, Zr, Ni, Mn, and Mg; Y is selected from at least one of K, Cs, Rb, Li, and Na; and Z is selected from at least one of Co, Ce, and La.

[0039] In some embodiments of the present invention, in the general formula of the active metal oxide component, the value of a ranges from 0.3 to 4.2; the value of b ranges from 0.4 to 4.0; the value of c ranges from 0.6 to 9.0; the value of d ranges from 0.1 to 0.8; the value of e ranges from 0.5 to 5.8; and x is the total number of oxygen atoms required to satisfy the valence of other elements.

[0040] In some embodiments of the present invention, the value of e / b ranges from 4.0 to 10.0; preferably from 5.5 to 8.2.

[0041] In some embodiments of the present invention, the catalyst is used in propylene pulse tests, and when the pulse interval is greater than 60s, the propylene conversion rate decreases by less than 10% in the first three propylene pulse tests; it has a fast lattice oxygen migration rate.

[0042] In some embodiments of the present invention, the support is selected from at least one of SiO2, Al2O3 and TiO2.

[0043] In some embodiments of the present invention, the content of the support is 5%-20% by weight based on the total weight of the catalyst; and / or the content of the active metal oxide component is 80%-95% by weight.

[0044] The fourth aspect of the present invention provides the use of the catalyst as described in the first aspect or the catalyst as described in the third aspect in the oxidation of propylene to prepare acrolein and acrylic acid.

[0045] Beneficial effects:

[0046] 1. The catalyst of the present invention has a rapid lattice oxygen migration rate, and when used in pulsed tests of propylene selective oxidation reaction, it has a high propylene conversion rate and a small rate of decrease in propylene conversion rate in multiple interval tests.

[0047] 2. In the catalyst preparation process of the present invention, air with a specific flow rate is used as the calcination atmosphere, and the catalyst calcination conditions are optimized by combining two-stage calcination with other specific calcination conditions such as calcination temperature and calcination time, thereby obtaining a catalyst with a fast lattice oxygen migration rate. Detailed Implementation

[0048] To make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present invention.

[0049] Example 1

[0050] This embodiment provides a method for preparing a propylene oxidation catalyst, including the preparation of 400g of (NH4)6Mo7O 24 ·4H2O was added to 400g of 70℃ warm water and stirred until completely dissolved. Then, 1.26g of KNO3 and 1.84g of CsNO3 were added to obtain material 1. Next, 71.6g of Bi(NO3)3·5H2O, 185g of Co(NO3)2·6H2O, 194g of Ni(NO3)2·6H2O, 70.4g of Mn(NO3)2 (50%), 196g of Ce(NO3)3·3H2O and 8.8g of La(NO3)3·3H2O were weighed and added to 60g of 70℃ hot water and stirred to dissolve to obtain material 2. 30g of 70℃ hot water was added to 80g of Fe(NO3)3·9H2O and stirred to dissolve to obtain material 3.

[0051] 120g of 40wt% silica sol was added to material 1, and then material 2 was added to material 1 under rapid stirring to form a preliminary slurry. After 5 minutes, material 3 was added, and the mixture was aged at 70℃ for 24 hours. It was then transferred to an oven and dried at 135℃ for 20 hours, and then pulverized. a) The powder sieved through a 20-40 mesh sieve was subjected to two-stage calcination and used for pulse testing. b) The remaining powder was used to form a 5*5*2 Raschig ring catalyst precursor. 600g of the obtained catalyst precursor was subjected to two-stage calcination. The calcination conditions were: first-stage calcination temperature 350℃, calcination time 70 minutes; second-stage calcination temperature 480℃, calcination time 200 minutes; the calcination atmosphere was air, with a flow rate of 15mL / (min·gcat). After calcination, the finished catalyst was obtained. The catalyst composition is:

[0052] Mo 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 3.27 Mn 1.05 Ce 2.0 La 0.09 K0.16 Cs 0.05 +8.6% SiO2.

[0053] a) Propylene Pulse Test for Catalyst

[0054] Two g of catalyst powder (sieved through a 20-40 mesh screen) after two-stage calcination was loaded into a reaction tube. The temperature was raised to 360℃, and N2 was introduced for 30 min to purge until the adsorbed oxygen on the catalyst surface was completely desorbed. Then, three propylene pulse tests were performed (5 mL / test), with a pulse interval of 90 s, at a reaction temperature of 360℃. The amount of unreacted propylene was quantified by gas chromatography-TCD external standard method. The propylene conversion rate was calculated by subtracting the amount of unreacted propylene from the amount of feed propylene: propylene conversion rate (%) = 1 - (moles of unreacted propylene C / moles of feed propylene C) × 100%.

[0055] The propylene conversion rates in the three propylene pulse tests were 95%, 92%, and 90%, respectively.

[0056] Example 2

[0057] This embodiment provides a method for preparing a propylene oxidation catalyst that is the same as that in Example 1, except that 167g of Ce(NO3)3·3H2O and 44g of La(NO3)3·3H2O are added. The catalyst composition is: Mo 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 3.27 Mn 1.05 Ce 1.7 La 0.45 K 0.16 Cs 0.05 +8.6% SiO2.

[0058] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three propylene pulse tests were 95%, 92% and 90% respectively.

[0059] Example 3

[0060] This embodiment provides a method for preparing a propylene oxidation catalyst that is the same as that in Example 1, except that 167g of Ce(NO3)3·3H2O and 44g of La(NO3)3·3H2O are added, and 62g of Mg(NO3)2·6H2O is also added. The catalyst components are:

[0061] Mo 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 3.27 Mn1.05 Mg 1.24 Ce 1.7 La 0.45 K 0.16 Cs 0.05 +8.6% SiO2.

[0062] The catalyst was subjected to propylene pulse tests according to the method in Example 1. The propylene conversion rates in the three propylene pulse tests were 96%, 93%, and 92%, respectively.

[0063] Example 4

[0064] This embodiment provides a method for preparing a propylene oxidation catalyst that is the same as that in Example 1, except that 167g of Ce(NO3)3·3H2O and 44g of La(NO3)3·3H2O are added, and 93g of Mg(NO3)2·6H2O is also added. The catalyst composition is as follows:

[0065] Mo 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 3.27 Mn 1.05 Mg 1.86 Ce 1.7 La 0.45 K 0.16 Cs 0.05 +8.6% SiO2.

[0066] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three propylene pulse tests were 95%, 94%, and 91%, respectively.

[0067] Example 5

[0068] This embodiment provides a method for preparing a propylene oxidation catalyst that is the same as that in Example 1, except that 139g of Ni(NO3)2·6H2O, 152g of Ce(NO3)3·3H2O, and 44g of La(NO3)3·3H2O are added, along with 62g of Mg(NO3)2·6H2O. The catalyst composition is: Mo 12 Bi 0.78 Fe 1.04 Ni 2.50 Co 3.27 Mn 1.05 Mg 1.24 Ce 1.55 La 0.4 5K 0.16 Cs 0.05 +8.6% SiO2.

[0069] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three pulse tests were 95%, 93%, and 91%, respectively.

[0070] Example 6

[0071] This embodiment provides a method for preparing a propylene oxidation catalyst that is the same as that in Example 1, except that 82.6 g of Bi(NO3)3·5H2O, 154 g of Ni(NO3)2·6H2O, 35.2 g of Mn(NO3)2 (50%), 167 g of Ce(NO3)3·3H2O, and 44 g of La(NO3)3·3H2O are added, along with 62 g of Mg(NO3)2·6H2O. The catalyst composition is as follows:

[0072] Mo 12 Bi 0.90 Fe 1.04 Ni 2.78 Co 3.27 Mn 0.58 Mg 1.24 Ce 1.7 La 0.45 K 0.16 Cs 0.05 +9.4% SiO2.

[0073] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three pulse tests were 96%, 94%, and 93%, respectively.

[0074] Example 7

[0075] This embodiment provides a method for preparing a propylene oxidation catalyst that is the same as that in Example 1, except that 204g of Co(NO3)2·6H2O, 128g of Ce(NO3)3·3H2O, and 44g of La(NO3)3·3H2O are added, along with 62g of Mg(NO3)2·6H2O. The catalyst composition is: Mo 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 3.60 Mn 1.05 Mg 1.24 Ce 1.30 La 0.4 5K 0.16 Cs 0.05 +8.6% SiO2.

[0076] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three pulse tests were 95%, 93%, and 91%, respectively.

[0077] Example 8

[0078] This embodiment provides a preparation method for a propylene oxidation catalyst that is the same as that in Example 1, except that 92g of Co(NO3)2·6H2O, 87.2g of Mn(NO3)2 (50%), 192g of Ce(NO3)3·3H2O, and 66g of La(NO3)3·3H2O are added, along with an additional 62g of Mg(NO3)2·6H2O. 180g of 40wt% silica sol is added to material 1. The catalyst composition is as follows:

[0079] Mo 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 1.62 Mn 1.30 Mg 1.24 Ce 1.95 La 0.67 K 0.16 Cs 0.05 +12.2% SiO2.

[0080] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three pulse tests were 95%, 93%, and 92%, respectively.

[0081] Example 9

[0082] This embodiment provides a method for preparing a propylene oxidation catalyst that is the same as that in Example 1, except that 169g of Co(NO3)2·6H2O, 182g of Ce(NO3)3·3H2O, and 44g of La(NO3)3·3H2O are added, along with 83g of Mg(NO3)2·6H2O. The catalyst composition is: Mo 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 3.00 Mn 1.05 Mg 1.6 Ce 1.85 La 0.4 5K 0.16 Cs 0.05 +8.6% SiO2.

[0083] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three pulse tests were 96%, 92%, and 91%, respectively.

[0084] Example 10

[0085] This embodiment provides a method for preparing a propylene oxidation catalyst that is the same as that in Example 1, except that 167g of Ce(NO3)3·3H2O and 66g of La(NO3)3·3H2O are added, and 124g of Mg(NO3)2·6H2O is also added. Material 1 contains 164g of 40wt% silica sol. The catalyst composition is: Mo... 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 3.27 Mn 1.05 Mg 2.48 Ce 1.7 La 0.68 K 0.16 Cs 0.05 +10.1% SiO2.

[0086] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three pulse tests were 96%, 94%, and 93%, respectively.

[0087] Example 11

[0088] This embodiment provides a preparation method for a propylene oxidation catalyst that is the same as that in Example 1, except that: 1.40 g of KNO3 is added; then 213.3 g of Co(NO3)2·6H2O, 83 g of Ce(NO3)3·3H2O, and 44 g of La(NO3)3·3H2O are added, and 62 g of Mg(NO3)2·6H2O is also added. The catalyst composition is: Mo 12 Bi 0.78 Fe 1.04 Ni 3.50 Co 3.77 Mn 1.05 Mg 1.24 Ce 0.85 La 0.45 K 0.18 Cs 0.05 +8.6% SiO2.

[0089] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three pulse tests were 95%, 94%, and 91%, respectively.

[0090] Example 12

[0091] This embodiment provides a preparation method for a propylene oxidation catalyst that is the same as that in Example 1, except that 82.6 g of Bi(NO3)3·5H2O, 169.4 g of Co(NO3)2·6H2O, 108 g of Ni(NO3)2·6H2O, 169.4 g of Ce(NO3)3·3H2O, and 44 g of La(NO3)3·3H2O are added, along with 93 g of Mg(NO3)2·6H2O. The catalyst composition is as follows:

[0092] Mo 12 Bi 0.90 Fe 1.04 Ni 1.95 Co 2.99 Mn 1.05 Mg 1.86 Ce 1.72 La 0.45 K 0.16 Cs 0.05 +8.6% SiO2.

[0093] The catalyst was subjected to propylene pulse tests according to the method in Example 1, and the propylene conversion rates in the three pulse tests were 95%, 93%, and 91%, respectively.

[0094] Example 13

[0095] This embodiment provides the same propylene oxidation catalyst prepared by the same method as in Example 12.

[0096] The catalyst was subjected to propylene pulse tests according to the method of Example 1, with the only difference being that the pulse interval was 60 seconds, and the propylene conversion rates in the three propylene pulse tests were 95%, 93%, and 90%, respectively.

[0097] Comparative Example 1

[0098] The catalyst preparation method in this comparative example is the same as that in Example 1, except that 100g of Fe(NO3)3·9H2O and other substances were added to 60g of 70°C hot water and stirred to dissolve, thus preparing material 2. The catalyst composition is: Mo 12 Bi 0.78 Fe 1.30 Ni 3.50 Co 3.27 Mn 1.05 Ce 2.0 La 0.09 K 0.16 Cs 0.05 +8.6% SiO2.

[0099] The catalyst was subjected to propylene pulse tests according to the method of Example 1. The propylene conversion rates in the three pulse tests were 94%, 87%, and 79%, respectively.

[0100] Comparative Example 2

[0101] The catalyst preparation method in this comparative example is the same as that in Example 1, except that 30g of 70°C hot water was added to 120g of Fe(NO3)3·9H2O and stirred to dissolve, yielding material 3. The catalyst composition is: Mo. 12 Bi 0.78 Fe 1.56 Ni 3.50 Co 3.27 Mn 1.05 Ce 2.0 La 0.09 K 0.16 Cs 0.05 +8.6% SiO2.

[0102] The catalyst was subjected to propylene pulse tests according to the method in Example 1. The propylene conversion rates in the three pulse tests were 95%, 87%, and 82%, respectively.

[0103] Comparative Example 3

[0104] The catalyst preparation method in this comparative example is the same as that in Example 1, except that the catalyst is subjected to a first-stage calcination at a temperature of 480°C for 200 min.

[0105] The catalyst was subjected to propylene pulse tests according to the method in Example 1. The propylene conversion rates in the three pulse tests were 95%, 88%, and 81%, respectively.

[0106] Comparative Example 4

[0107] The catalyst preparation method of this comparative example is the same as that of Example 1, the only difference being that the calcination atmosphere is oxygen-enriched air with an oxygen content of 30%.

[0108] The catalyst was subjected to propylene pulse tests according to the method of Example 1, and the propylene conversion rates in the three pulse tests were 94%, 89%, and 80%, respectively.

[0109] Experimental Example 1

[0110] 300g of each of the catalysts prepared in Examples 1-12 and Comparative Examples 1-4 were respectively packed into fixed-bed reactors. The inner diameter of the fixed-bed reactors was 25.4mm and the length of the reactors was 1300mm. The raw material propylene: air: water vapor was introduced into the fixed-bed reactors at a ratio of 10:73:17, and the reactors were operated at a temperature of 375℃ and a pressure of 0.1kg / cm². 2 1200 h -1The reaction was carried out under the specified conditions for 2000 h. The reaction product was absorbed with dilute acid at 0 °C, analyzed by gas chromatography, and the carbon balance was calculated. Data with a carbon balance of 95%-105% inactivation was considered valid. The following calculations were performed after product analysis:

[0111] Propylene conversion rate (%) = 1 - (number of moles of unreacted propylene C / number of moles of C in all products) × 100%

[0112] Yield of a certain product (%) = (Number of moles of C of the product produced / Total number of moles of C of all products) × 100%

[0113] Product selectivity (%) = Product yield / Propylene conversion rate × 100%

[0114] The results are shown in Table 1.

[0115] Table 1 Product Analysis Results

[0116]

[0117]

[0118] 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 propylene oxidation catalyst, said catalyst comprising a support and an active metal oxide component, characterized in that, The active metal oxide comprises the following components: Mo, Bi, Fe, X, Y, Z, and O, wherein component X is selected from at least one of Ag, Zr, Ni, Mn, and Mg; component Y is selected from at least one of K, Cs, Rb, Li, and Na; component Z is selected from at least one of Co, Ce, and La; the molar ratio of components Mo, Bi, Fe, X, Y, and Z is 12:(0.3-4.2):(0.4-4.0):(0.6-9.0):(0.1-0.8):(0.5-5.8); and the number of moles of component O is the total number of oxygen atoms required to satisfy the valence of the other components. In the active metal oxide component, the molar ratio of component Z to component Fe is (5.36 / 1.04) to 8.2; The method for preparing the catalyst includes: mixing an active metal oxide precursor with a support precursor, and then aging and calcining the mixture to obtain the catalyst. The roasting atmosphere is air; the roasting includes two stages of roasting. The conditions for the two-stage roasting include: the first stage roasting temperature is 300-400℃; the roasting time is 60-90 min; the second stage roasting temperature is 450-550℃; the roasting time is 100-450 min.

2. The catalyst according to claim 1, characterized in that, In the active metal oxide component, the molar ratio of component Z to component Fe is 5.5-8.

2.

3. The catalyst according to claim 1, characterized in that, The catalyst is used in propylene pulse tests, and when the pulse interval is greater than 60s, the propylene conversion rate decreases by less than 10% in the first three propylene pulse tests.

4. The catalyst according to any one of claims 1-3, characterized in that, The support is selected from at least one of SiO2, Al2O3 and TiO2.

5. The catalyst according to claim 4, characterized in that, The specific surface area of ​​the carrier is 70-120 m². 2 / g; and / or, the pore volume of the carrier is 0.06-0.11 mL / g.

6. The catalyst according to any one of claims 1-3, characterized in that, Based on the total weight of the catalyst, the content of the support is 5%-20% by weight; and / or, the content of the active metal oxide component is 80%-95% by weight.

7. A method for preparing a catalyst according to any one of claims 1-6, characterized in that, include: The catalyst is obtained by mixing an active metal oxide precursor with a support precursor and then aging and calcining it. The roasting atmosphere is air; The roasting process includes two stages; The conditions for the two-stage roasting include: the first stage roasting temperature is 300-400℃; the roasting time is 60-90 min; the second stage roasting temperature is 450-550℃; the roasting time is 100-450 min.

8. The method for preparing the catalyst according to claim 7, characterized in that, The air flow rate is 10-18 mL / (min·gcat).

9. The method for preparing the catalyst according to claim 8, characterized in that, The air flow rate is 12-17 mL / (min·gcat).

10. The method for preparing the catalyst according to claim 7, characterized in that, The active metal oxide precursor comprises a soluble salt of a metal element represented by the general formula of the active metal oxide component, obtained by compounding; and / or, the carrier precursor comprises silicon dioxide, silica sol, or titanium dioxide.

11. The preparation method according to claim 7, characterized in that, The active metal oxide component of the active metal oxide precursor is Fe, which is added separately at the end for mixing.

12. The preparation method according to claim 7, characterized in that, The conditions for the two-stage roasting include: the first stage roasting temperature is 320-390℃; and / or the second stage roasting temperature is 460-520℃; and the roasting time is 120-380 min.

13. A propylene oxidation catalyst prepared by the preparation method according to any one of claims 7-12.

14. The application of the catalyst according to any one of claims 1-6 or the catalyst according to claim 13 in the oxidation of propylene to prepare acrolein and acrylic acid.

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