Light olefin ammoxidation catalyst and its preparation method and application

Abstract

The present invention discloses a catalyst for the ammoxidation of light olefins, a preparation method thereof, and an application thereof. The lattice oxygen concentration of the catalyst of the present invention is higher than that of α-Bi2Mo3O 12 The lattice oxygen concentration of α-Bi2Mo3O 12 The CAS number of the catalyst is 13595-85-2. The raw materials for preparing the catalyst include an active component and a carrier that has been subjected to a aging treatment. The carrier includes silicon dioxide and a carrier additive, and the carrier additive is an inorganic base. The catalyst of the present invention has a high lattice oxygen concentration and is used in the production of nitrile compounds. It has the advantages of high raw material conversion rate and high yield of product nitrile compounds, and the catalyst performance is stable.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, in particular to a low-carbon olefin ammoxidation catalyst and a preparation method thereof, and a method for producing nitrile compounds. Background Art

[0002] Currently, the industrial production of propylene to unsaturated nitriles via ammoxidation generally adopts the Sohio fluidized bed process. The catalyst is the core of this technology. From the perspective of the main elements of the catalyst, it can be mainly classified into Mo-Bi and Sb-Fe series, among which Mo-Bi series catalysts occupy a major position. In recent years, the research and performance improvement of catalysts have also been mainly carried out around them, and a rich theoretical foundation has been formed, such as oxidation-reduction cycle, active site isolation, lattice defects and interphase synergy.

[0003] By introducing metal components with variable valence states, such as Fe and Ce, into the catalyst, the redox properties of the catalyst can be improved, accelerating the recovery of the catalyst's active components to an effective state. By introducing metal elements with ionic radii greater than 0.8 nm and less than 0.8 nm, such as Cr, Ni, Mg, Mn, Zn, and Al, they can act as structural and electronic additives, improving the catalyst's structure and stability. By introducing rare earth elements, the amount of lattice oxygen in the catalyst can be increased, improving the catalyst's catalytic performance. By introducing elements such as Cs, Rb, P, B, and Al, the catalyst's surface can be modified and its acidity and alkalinity adjusted, improving the catalyst's selectivity and activity.

[0004] CN 103769129A discloses a fluidized bed catalyst for ammoxidation to produce unsaturated nitrile and a preparation method thereof, which uses silica sol as a carrier and contains an active component represented by the following general formula: Mo 12 Bi a Fe b Ni c X d Y e Z f Q g K h T i O x, wherein: X is at least one selected from Mg, Co, Ca, Be, Cu, Zn, Pb, Mn or Te; Y is at least one selected from La, Ce or Sm; Z is at least one selected from Rb, Li or Cs; Q is at least one selected from Sb, Nb or Ta; T is at least one selected from Be, Ca or Ba; a is in the range of 0.1 to 6.0; b is in the range of 0.1 to 10.0; c is in the range of 0.1 to 10.0; d is in the range of 0.1 The catalyst comprises a catalyst with a mass of 1000 Å and a mass of 1000 Å. The catalyst comprises a catalyst with a mass of 1000 Å and a mass of 2 ...

[0005] In addition, the catalysts in the prior art have the problem of low propylene conversion rate and acrylonitrile yield when performing propylene ammoxidation to produce acrylonitrile. Summary of the Invention

[0006] In response to the above-mentioned problems existing in the prior art, the present invention provides a new low-carbon olefin ammoxidation catalyst and a preparation method thereof. The active components of the low-carbon olefin ammoxidation catalyst of the present invention are relatively simple, and the catalyst has a high lattice oxygen concentration. When used to produce nitrile compounds, it has the advantages of high raw material conversion rate and high yield of product nitrile compounds, and the catalyst performance is stable.

[0007] The first aspect of the present invention provides a catalyst for the ammoxidation of light olefins, wherein the lattice oxygen concentration of the catalyst is higher than that of α-Bi2Mo3O 12 The lattice oxygen concentration of α-Bi2Mo3O 12 The CAS number is 13595-85-2; the raw materials for preparing the catalyst include active components and a carrier that has been aged, the carrier includes silicon dioxide and a carrier additive, and the carrier additive is an inorganic base.

[0008] According to some embodiments of the present invention, preferably, the lattice oxygen concentration of the catalyst is α-Bi2Mo3O 12 The lattice oxygen concentration of the catalyst is 1.1 to 5 times, preferably 1.5 to 4.5 times. In the present invention, the lattice oxygen concentration of the catalyst is compared with the standard material α-Bi2Mo3O 12In comparison, the improved catalyst is expressed as the multiple of the increase in lattice oxygen concentration, which is not limited by instruments and testing methods.

[0009] According to some embodiments of the present invention, after 20 in-situ light olefin pulses, a further 20 light olefin pulses are performed using the light olefin ammoxidation catalyst of the present invention after sufficient lattice oxygen replenishment. The light olefin conversion rate decreases by less than 6 percentage points. In preferred embodiments, the decrease can be less than 4.1 percentage points, or even only 1.8 percentage points. In the present invention, the decrease is 1.8 percentage points, for example, from 90% to 88.2%, a difference of 1.8 percentage points.

[0010] According to some embodiments of the present invention, preferably, the aging treatment conditions include: a temperature of 40 to 150° C., preferably 50 to 100° C.; and a time of 10 minutes to 10 hours, preferably 30 minutes to 5 hours.

[0011] According to some embodiments of the present invention, preferably, the carrier additive is selected from at least one of potassium hydroxide, calcium hydroxide, magnesium hydroxide, cobalt hydroxide, nickel hydroxide, zirconium hydroxide, and ammonium hydroxide, preferably ammonium hydroxide. In the present invention, the carrier additive can be added in solid form or in liquid form after being dissolved in a liquid. In a more preferred embodiment, the carrier additive is an aqueous ammonium hydroxide solution.

[0012] According to some embodiments of the present invention, preferably, the general formula of the active component is Mo 11.0 Bi b Fe c D d E e O x , wherein D is selected from at least one of Li, Na, K, Rb and Cs; E is selected from at least one of Ca, Mg, La, Ce, Pr, Nd, Zr, Te, Sb, Ni, Cr, W and Nb; wherein the value range of b is 0.1 to 5.0; the value range of c is 0.1 to 5.0; the value range of d is 0.1 to 5.0; the value range of e is 0.1 to 5.0; and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

[0013] According to some embodiments of the present invention, preferably, the weight of the carrier is 35 to 65 weight % of the weight of the catalyst.

[0014] According to some embodiments of the present invention, preferably, the weight of the carrier additive is 0.1 to 5 weight % of the weight of the carrier.

[0015] The second aspect of the present invention provides a method for preparing an ammonia oxidation catalyst, comprising: mixing a solution containing an active component precursor with a solution containing a carrier that has been aged, drying and calcining, wherein the carrier comprises silica and a carrier additive, and the carrier additive is an inorganic base.

[0016] According to some embodiments of the present invention, preferably, the solution containing the active component precursor includes a solution containing a Mo precursor and a solution containing a Bi precursor, a Fe precursor, a D precursor, and an E precursor, wherein D is selected from at least one of Li, Na, K, Rb, and Cs; and E is selected from at least one of Ca, Mg, La, Ce, Pr, Nd, Zr, Te, Sb, Ni, Cr, W, and Nb.

[0017] According to some embodiments of the present invention, preferably, a solution containing a Mo precursor is mixed with a solution containing a carrier that has been aged, and then mixed with solutions containing a Bi precursor, a Fe precursor, a D precursor, and an E precursor.

[0018] According to some embodiments of the present invention, preferably, the method for preparing a solution containing a carrier comprises: adding a carrier additive to a solution containing silicon dioxide. The solution containing silicon dioxide may be in a solid or liquid state, such as, but not limited to, silicon dioxide, silica sol, or the like.

[0019] According to some embodiments of the present invention, preferably, the adding rate is 0.2 to 5 g / min, more preferably, the adding rate is 0.5 to 2 g / min.

[0020] According to some embodiments of the present invention, preferably, the calcination conditions include: a temperature of 500-680°C, preferably 550-650°C.

[0021] According to some embodiments of the present invention, preferably, the calcination conditions include: a time of 0.2 to 4 hours, preferably 0.5 to 2.5 hours.

[0022] According to some embodiments of the present invention, the active component precursor may be a soluble salt of the active component, for example, the soluble salt of Mo may be but is not limited to (NH4)6Mo7O 24 For another example, the soluble salt of Bi may be, but is not limited to, Bi(NO 3 ) 3 .

[0023] According to some embodiments of the present invention, preferably, the carrier additive is selected from at least one of potassium hydroxide, calcium hydroxide, magnesium hydroxide, cobalt hydroxide, nickel hydroxide, zirconium hydroxide, and ammonium hydroxide, preferably ammonium hydroxide. In the present invention, the carrier additive can be added in solid form or in liquid form after being dissolved in a liquid. In a more preferred embodiment, the carrier additive is an aqueous ammonium hydroxide solution.

[0024] According to some embodiments of the present invention, preferably, the amount of the active component precursor is such that in the prepared light olefin ammoxidation catalyst, the active component has the general formula of Mo 11.0 Bi b Fe c D d E e O x , wherein D is selected from at least one of Li, Na, K, Rb and Cs; E is selected from at least one of Ca, Mg, La, Ce, Pr, Nd, Zr, Te, Sb, Ni, Cr, W and Nb; wherein the value range of b is 0.1 to 5.0; the value range of c is 0.1 to 5.0; the value range of d is 0.1 to 5.0; the value range of e is 0.1 to 5.0; and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

[0025] According to some embodiments of the present invention, preferably, the weight of the carrier is 35 to 65 weight % of the weight of the catalyst.

[0026] According to some embodiments of the present invention, preferably, the weight of the carrier additive is 0.1 to 5 weight % of the weight of the carrier.

[0027] According to a specific embodiment of the present invention, the preparation method may include but is not limited to:

[0028] (1) dissolving the Mo precursor to obtain solution I;

[0029] (2) dissolving a Bi precursor, an Fe precursor, a D precursor, and an E precursor (i.e., elements other than Mo) to obtain a solution II, wherein D is selected from at least one of Li, Na, K, Rb, and Cs; and E is selected from at least one of Ca, Mg, La, Ce, Pr, Nd, Zr, Te, Sb, Ni, Cr, W, and Nb;

[0030] (3) mixing a required amount of carrier silica sol and a carrier additive to obtain a mixed solution III, and performing an aging treatment;

[0031] (4) mixing solution I with the aging solution III, and then adding solution II to obtain a precipitated slurry;

[0032] (5) The slurry is spray-dried and calcined at 500-680°C for 0.2-4 hours to obtain a catalyst.

[0033] The third aspect of the present invention provides an ammonia oxidation catalyst obtained according to the above preparation method, wherein the lattice oxygen concentration of the catalyst is higher than that of α-Bi2Mo3O 12 The lattice oxygen concentration of α-Bi2Mo3O12 The CAS number is 13595-85-2; the raw materials for preparing the catalyst include active components and a carrier that has been aged, the carrier includes silicon dioxide and a carrier additive, and the carrier additive is an inorganic base.

[0034] According to some embodiments of the present invention, preferably, the lattice oxygen concentration of the catalyst is α-Bi2Mo3O 12 The lattice oxygen concentration is 1.1 to 5 times, preferably 1.5 to 4.5 times.

[0035] According to some embodiments of the present invention, after 20 in-situ light olefin pulses, 20 light olefin pulse reactions are performed again after fully replenishing lattice oxygen using the above-mentioned light olefin ammoxidation catalyst of the present invention, and the light olefin conversion rate decreases by less than 6 percentage points. In preferred cases, the decrease can be less than 4.1 percentage points, or even only 1.8 percentage points.

[0036] According to some embodiments of the present invention, preferably, the general formula of the active component is Mo 11.0 Bi b Fe c D d E e O x , wherein D is selected from at least one of Li, Na, K, Rb and Cs; E is selected from at least one of Ca, Mg, La, Ce, Pr, Nd, Zr, Te, Sb, Ni, Cr, W and Nb; wherein the value range of b is 0.1 to 5.0; the value range of c is 0.1 to 5.0; the value range of d is 0.1 to 5.0; the value range of e is 0.1 to 5.0; and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

[0037] According to some embodiments of the present invention, preferably, the weight of the carrier is 35 to 65 weight % of the weight of the catalyst.

[0038] According to some embodiments of the present invention, preferably, the weight of the carrier additive is 0.1 to 5 weight % of the weight of the carrier.

[0039] A fourth aspect of the present invention provides a method for producing nitrile compounds, comprising: contacting a light olefin feedstock, ammonia and air to carry out an ammoxidation reaction in the presence of the above-mentioned light olefin ammoxidation catalyst or the light olefin ammoxidation catalyst obtained according to the above-mentioned preparation method.

[0040] According to some embodiments of the present invention, preferably, the light olefin raw material is propylene and / or isobutylene.

[0041] According to some embodiments of the present invention, preferably, the molar ratio of the light olefin feedstock, ammonia and air is 1:1.05-1.3:9.2-9.8.

[0042] According to some embodiments of the present invention, preferably, the reaction conditions include: a temperature of 420-440°C.

[0043] According to some embodiments of the present invention, preferably, the reaction conditions include: a reaction pressure of 0.06 to 0.14 MPa.

[0044] According to some embodiments of the present invention, preferably, the propylene loading (WWH) of the catalyst is 0.06 to 0.10 h -1 .

[0045] According to some embodiments of the present invention, the nitrile compound may be, but is not limited to, acrylonitrile, methacrylonitrile, and the like.

[0046] Beneficial effects of the present invention:

[0047] (1) The present invention improves the propylene conversion rate, acrylonitrile selectivity and catalyst stability by providing a catalyst with specific elements and proportions and adding a carrier additive during the catalyst preparation process. The lattice oxygen of the catalyst was tested by the in-situ pulse method, and it was found that the catalyst of the present invention has a high lattice oxygen concentration, which is higher than that of the standard material α-Bi2Mo3O 12 (CAS: 13595-85-2, also known as Alpha-Bi2Mo3O 12 ) compared to α-Bi2Mo3O 12 The lattice oxygen concentration is 1.1 to 5 times, preferably 1.5 to 4.5 times, of the lattice oxygen concentration. After 20 in-situ light olefin pulses, 20 light olefin pulse reactions are performed again using the light olefin ammoxidation catalyst of the present invention to fully replenish lattice oxygen. The light olefin conversion rate decreases by less than 6 percentage points. In preferred cases, the decrease can be less than 4.1 percentage points, or even only 1.8 percentage points.

[0048] (2) As demonstrated in the subsequent examples of the present invention, the activity of the catalyst of the present invention was evaluated in a fluidized bed reactor with an inner diameter of 38 mm, wherein the catalyst loading was 400 g, the reaction temperature was 430°C, the air:propylene molar ratio was 9.7:1, the ammonia:propylene molar ratio was 1.25:1, the reaction pressure was 0.085 MPa, and the propylene load (WWH) was 0.06 h -1 Under the conditions of , the propylene conversion rate is greater than 98%, and the acrylonitrile single-pass yield reaches more than 83%, achieving good results. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1The catalyst of Example 1 of the present invention was subjected to 20 in-situ propylene pulses, and then the light olefin ammoxidation catalyst of Example 1 was fully replenished with lattice oxygen and then pulsed with propylene 20 times again. The propylene conversion rate of each pulse is shown in FIG.

[0050] Figure 2 The catalyst of Comparative Example 6 was subjected to 20 in-situ propylene pulses, and then the light olefin ammoxidation catalyst of Comparative Example 6 was fully replenished with lattice oxygen and then pulsed with propylene 20 times again. The propylene conversion rate of each pulse is shown in FIG.

[0051] Figure 3 For α-Bi2Mo3O 12 Compared with the lattice oxygen concentration of the catalyst of Example 1 and the catalyst of Comparative Example 6, the lattice oxygen concentration of Alpha-Bi2Mo3O 12 α-Bi2Mo3O 12 . DETAILED DESCRIPTION

[0052] In order to make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are only for illustration and do not limit the scope of application of the present invention.

[0053] The test method of the present invention and the equipment used in the test are as follows:

[0054] Unless otherwise specified, the raw materials used in the examples and comparative examples are all publicly available in the prior art, and can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0055] (1) In the present invention, the definitions of propylene conversion, acrylonitrile selectivity and per pass yield are as follows:

[0056]

[0057]

[0058]

[0059]

[0060] (2) The catalyst in-situ pulse test was carried out on a chemical adsorption device equipped with a gas chromatograph. The catalyst sample loading amount was 0.3 g, the pulse gas quantitative loop was 0.25 ml, and the pulse interval time was 11 minutes. An inert gas was used as the carrier gas, preferably nitrogen, argon and helium, and most preferably helium. The tail gas was detected for composition changes using a hydrogen flame ionization detector FID and a thermal conductivity TCD detector. Before testing the catalyst sample, a blank experiment was performed. The temperature was programmed to 380-450°C. Before the start of the pulse reaction, an inert gas was purged for 2 hours, followed by 20 pulses of light olefin gas. Then, 10% O2 pulse gas was passed through to measure the number of moles of O2 consumed in each pulse. Until there was no significant change in the number of O2 moles in the last few times, it was considered that the catalyst had fully replenished the lattice oxygen available for the reaction. The lattice oxygen concentration of the catalyst available for the reaction each time was represented by the symbol C, in units of mol / g.

[0061] C = moles of O2 consumed per pulse / mass of catalyst.

[0062] The conversion of light olefins per pulse is defined as follows:

[0063] Conversion rate of light olefins (%) = number of moles of light olefins removed in each pulse reaction / number of moles of light olefins in a blank experiment under the same conditions × 100.

[0064] Unless otherwise specified, percentages and concentrations in the Examples and Comparative Examples are percentages by weight.

[0065] [Example 1]

[0066] 985.0 g (NH4)6Mo7O 24 ·4H2O was dissolved in 910 g of water to obtain solution (I). 131.8 g of Bi(NO3)3·5H2O, 657.6 g of Ni(NO3)2·6H2O, 276.3 g of Fe(NO3)3·9H2O, 138.6 g of Mg(NO3)2·6H2O, 4.1 g of KOH, and 19.2 g of Ca(NO3)3·4H2O were heated and dissolved in 180 g of water to obtain solution (II). 116 g of a 10% aqueous ammonia solution was added to 1250 g of silica sol having a silicon content of 40% at a rate of 1.5 g / min to form a mixed solution (III), in which the ammonia solution accounted for 2.0% by weight. The mixed solution (III) was aged at 80°C for 1.5 hours. Solution (I) and solution (III) were mixed, and then solution (II) was added to obtain a precipitate slurry. The prepared slurry was formed into microspheres and dried in a spray dryer, and finally calcined in a rotary calciner at 600 ° C for 2 hours to obtain a Mo- 11.0 Bi 0.5 Fe 1.3 K 0.1 Ni 4.5 Mg1.1 Ca 0.2 O x The catalyst comprises 31% by weight of the carrier.

[0067] The lattice oxygen concentration of the obtained catalyst is α-Bi2Mo3O with CAS number 13595-85-2 12 The lattice oxygen concentration was 3.7 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 2.3 percentage points. The results are shown in Table 1.

[0068] [Example 2]

[0069] 1013.0 g (NH4)6Mo7O 24 ·4H2O was dissolved in 965 g of water to obtain solution (I). 246.8 g of Bi(NO3)3·5H2O, 786.1 g of Ni(NO3)2·6H2O, 342.1 g of Fe(NO3)3·9H2O, 201.1 g of Mg(NO3)2·6H2O, 15.3 g of RbNO3, and 239.4 g of La(NO3)3·6H2O were dissolved in 220 g of water by heating to obtain solution (II). 307 g of a 1% KOH solution was added to 2138 g of silica sol having a silicon content of 40% at a rate of 1.8 g / min to form a mixed solution (III), in which the weight percentage of KOH was 0.4%. The mixed solution (III) was aged at 65°C for 2.0 hours. Solution (I) and solution (III) were mixed, and then solution (II) was added to obtain a precipitate slurry. The prepared slurry was formed into microspheres and dried in a spray dryer, and finally calcined in a rotary calciner at 610°C for 1.5 hours to obtain a Mo- 11.0 Bi 1.0 Fe 1.6 Rb 0. 2Ni 5.2 Mg 1.5 La 1.1 K 0.1 O x The catalyst comprises 39% by weight of the carrier.

[0070] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 3.2 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by only 2.1 percentage points. The results are shown in Table 1.

[0071] [Example 3]

[0072] 990.0 g (NH4)6Mo7O 24·4H2O was dissolved in 810 g of water to obtain solution (I). 269.8 g of Bi(NO3)3·5H2O, 651.3 g of Ni(NO3)2·6H2O, 486.7 g of Fe(NO3)3·9H2O, 5.9 g of CrO3, 6.8 g of CsNO3, and 146.9 g of Pr(NO3)3·6H2O were dissolved in 225 g of water by heating to obtain solution (II). 238 g of a 1% KOH solution was added to 1850 g of silica sol having a silicon content of 40% at a rate of 1.6 g / min to form a mixed solution (III), in which the weight percentage of KOH was 0.3%. The mixed solution (III) was aged at 70°C for 2.0 hours. Solution (I) and solution (III) were mixed, and then solution (II) was added to obtain a precipitate slurry. The prepared slurry was formed into microspheres and dried in a spray dryer, and finally calcined in a rotary calciner at 600 ° C for 2 hours to obtain a Mo- 11.0 Bi 1.1 Fe 2.4 Cs 0.1 Ni 4.4 Pr 0.7 Cr 0. 1K 0.1 O x The catalyst comprises 37% by weight of the carrier.

[0073] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 2.8 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then subjected to another 20 propylene pulses. The propylene conversion rate dropped by only 2.4 percentage points. The results are shown in Table 1.

[0074] [Example 4]

[0075] 898.0 g (NH4)6Mo7O 24·4H2O was dissolved in 780 g of water to obtain solution (I). 210.6 g of Bi(NO3)3·5H2O, 367.1 g of Ni(NO3)2·6H2O, 548.1 g of Fe(NO3)3·9H2O, 106.5 g of Mg(NO3)2·6H2O, 3.5 g of KOH, and 212.3 g of Zr(NO3)3·5H2O were dissolved in 210 g of water by heating to obtain solution (II). 98.5 g of a 10% aqueous ammonia solution was added to 1560 g of silica sol having a silicon content of 40% at a rate of 1.5 g / min to form a mixed solution (III), in which the ammonia solution accounted for 1.6% by weight. The mixed solution (III) was aged at 85°C for 1.0 hour. Solution (I) and solution (III) were mixed, and then solution (II) and 14.5 g of Sb2O3 powder were added to obtain a precipitate slurry. The prepared slurry was formed into microspheres and dried in a spray dryer, and finally calcined in a rotary calciner at 620°C for 1.5 hours to obtain a Mo- 11.0 Bi 0.9 Fe 2.9 K 0.1 Ni 2.7 Mg 0.9 Zr 1.1 Sb 0.1 O x The catalyst comprises 36% by weight of the carrier.

[0076] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 2.5 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then subjected to another 20 propylene pulses. The propylene conversion dropped by only 1.8 percentage points. The results are shown in Table 1.

[0077] [Example 5]

[0078] 1104 g (NH4)6Mo7O 24·4H2O was dissolved in 935 g of water to obtain solution (I). 267.8 g of Bi(NO3)3·5H2O, 453.2 g of Ni(NO3)2·6H2O, 635.8 g of Fe(NO3)3·9H2O, 108.3 g of Ce(NO3)2·6H2O, 6.9 g of RbNO3, and 89.6 g of Ca(NO3)3·4H2O were heated and dissolved in 175 g of water to obtain solution (II). 127 g of a 10% aqueous ammonia solution was added to 2130 g of silica sol having a silicon content of 40% at a rate of 2.0 g / min to form a mixed solution (III), in which the weight percentage of the aqueous ammonia solution was 1.5%. The mixed solution (III) was aged at 90°C for 30 minutes. Solution (I) and solution (III) were mixed, and then solution (II) was added to obtain a precipitate slurry. The prepared slurry was formed into microspheres and dried in a spray dryer, and finally calcined in a rotary calciner at 620°C for 2.5 hours to obtain a Mo- 11.0 Bi 1.0 Fe 2.8 Rb 0.1 Ni 2.7 Ce 0.4 Ca 0.7 O x The catalyst comprises 39% by weight of the carrier.

[0079] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. It was found that the propylene conversion rate dropped by only 2.5 percentage points.

[0080] [Example 6]

[0081] The method of Example 1 was followed, except that 116 g of a 10% aqueous ammonia solution was added to 1250 g of silica sol having a silicon content of 40% at a rate of 1.0 g / min to form a mixed solution (III).

[0082] The lattice oxygen concentration of the obtained catalyst was measured to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 3.1 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 2.9 percentage points. The results are shown in Table 1.

[0083] [Example 7]

[0084] The method of Example 1 was followed, except that 116 g of a 10% aqueous ammonia solution was added to 1250 g of silica sol having a silicon content of 40% at a rate of 5.0 g / min to form a mixed solution (III).

[0085] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 1.8 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 5.7 percentage points. The results are shown in Table 1.

[0086] [Example 8]

[0087] The method of Example 1 was followed, except that 116 g of a 10% aqueous ammonia solution was added to 1250 g of silica sol having a silicon content of 40% at a rate of 0.5 g / min to form a mixed solution (III).

[0088] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 2.6 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 3.2 percentage points. The results are shown in Table 1.

[0089] [Example 9]

[0090] The method of Example 1 was followed, except that the mixed solution (III) was aged at 100°C for 50 minutes.

[0091] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 1.5 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 3.4 percentage points. The results are shown in Table 1.

[0092] [Example 10]

[0093] The method of Example 1 was followed, except that the mixed solution (III) was aged at 50°C for 5 hours.

[0094] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 2.9 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 3.2 percentage points. The results are shown in Table 1.

[0095] [Example 11]

[0096] The method of Example 1 was followed, except that the mixed solution (III) was aged at 40°C for 10 hours.

[0097] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 1.7 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 4.1 percentage points. The results are shown in Table 1.

[0098] [Example 12]

[0099] The method of Example 1 was followed, except that the mixed solution (III) was aged at 150°C for 30 minutes.

[0100] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 1.4 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 5.6 percentage points. The results are shown in Table 1.

[0101] [Comparative Example 1]

[0102] The method of Example 1 was followed, except that no ammonia solution was added.

[0103] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 0.9 times that of the catalyst. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 7.8 percentage points. The results are shown in Table 1.

[0104] [Comparative Example 2]

[0105] The method of Example 1 was followed, except that the ammonia solution was added at a rate of 10 g / min. It was found that the silica sol solution immediately gelled.

[0106] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 0.3 times the original concentration. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 14.6 percentage points. The results are shown in Table 1.

[0107] [Comparative Example 3]

[0108] The method of Example 1 was followed, except that 412 g of a 10% by weight ammonia solution was added to the silica sol, and the ammonia solution accounted for 7.6% by weight. It was found that the silica sol solution immediately gelled.

[0109] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 0.2 times the original concentration. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 19.2 percentage points. The results are shown in Table 1.

[0110] [Comparative Example 4]

[0111] The method of Example 2 was followed, except that no KOH solution was added.

[0112] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 0.7 times the original concentration. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 10.3 percentage points. The results are shown in Table 1.

[0113] [Comparative Example 5]

[0114] The method of Example 2 was followed, except that a KOH solution with a concentration of 1% was added at a rate of 20 g / min. It was found that the silica sol solution immediately gelled.

[0115] The lattice oxygen concentration of the obtained catalyst was determined to be α-Bi2Mo3O with CAS number 13595-85-2. 12 The lattice oxygen concentration was 0.4 times the original concentration. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 10.2 percentage points. The results are shown in Table 1.

[0116] [Comparative Example 6]

[0117] The method of Example 1 is the same, except that no aging treatment is performed, that is:

[0118] 985.0 g (NH4)6Mo7O 24·4H2O was dissolved in 910 g of water to obtain solution (I). 131.8 g of Bi(NO3)3·5H2O, 657.6 g of Ni(NO3)2·6H2O, 276.3 g of Fe(NO3)3·9H2O, 138.6 g of Mg(NO3)2·6H2O, 4.1 g of KOH, and 19.2 g of Ca(NO3)3·4H2O were dissolved in 180 g of water by heating to obtain solution (II). 116 g of a 10% aqueous ammonia solution was added to 1250 g of silica sol having a silicon content of 40% at a rate of 1.5 g / min to form a mixed solution (III), in which the weight percentage of the aqueous ammonia solution was 2.0%. Solutions (I) and (III) were mixed, and then solution (II) was added to obtain a precipitate slurry. The prepared slurry was formed into microspheres and dried in a spray dryer, and finally calcined in a rotary calciner at 600 ° C for 2 hours to obtain a Mo- 11.0 Bi 0.5 Fe 1.3 K 0.1 Ni 4.5 Mg 1.1 Ca 0.2 O x The catalyst comprises 31% by weight of the carrier.

[0119] The lattice oxygen concentration of the obtained catalyst is α-Bi2Mo3O with CAS number 13595-85-2 12 The lattice oxygen concentration was 0.5 times the original concentration. After 20 propylene in-situ pulses, the catalyst was oxygenated and then pulsed with 20 more propylene pulses. The propylene conversion dropped by 4.6 percentage points. The results are shown in Table 1.

[0120] Test Example 1

[0121] The catalysts prepared in Examples 1 to 12 and Comparative Examples 1 to 6 were used to perform the reaction of propylene ammoxidation to synthesize acrylonitrile under the following conditions. The results are shown in Table 1.

[0122] The reactor and process conditions are as follows:

[0123] φ38 mm fluidized bed reactor

[0124] Reaction temperature 430℃

[0125] Reaction pressure 0.085MPa

[0126] Catalyst loading 400g

[0127] Catalyst propylene loading (WWH) 0.06 hours -1

[0128] The raw material ratio (molar): propylene / ammonia / air = 1 / 1.25 / 9.7.

[0129]

[0130]

[0131] Test Example 2

[0132] The catalyst of Example 1 was subjected to 20 propylene pulses in situ, and the light olefin ammoxidation catalyst of Example 1 was fully supplemented with lattice oxygen and then pulsed with propylene 20 times. The propylene conversion rate of each pulse was as follows: Figure 1 .

[0133] The catalyst of Comparative Example 6 was subjected to 20 propylene pulses in situ, and the catalyst of Comparative Example 6 was fully replenished with lattice oxygen and then pulsed with propylene 20 times. The propylene conversion rate of each pulse was Figure 2 .

[0134] Test Example 3

[0135] With α-Bi2Mo3O 12 The lattice oxygen concentration of the catalysts of Example 1 and Comparative Example 6 was increased by 4 pulses each time. Figure 3 . Figure 3 Medium Alpha-Bi2Mo3O 12 α-Bi2Mo3O 12 .

[0136] from Figure 1 and Figure 2 It can be seen that in Example 1, a specific amount of ammonium hydroxide solution was added at a certain rate. After 20 propylene in-situ pulses, the catalyst was oxygenated and then subjected to 20 propylene pulses again. The decrease in propylene conversion was relatively low.

[0137] from Figure 3 It can be seen that Example 1 has a higher lattice oxygen concentration.

[0138] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, under the technical enlightenment provided by the present invention, as common knowledge in the art, other equivalent variations and improvements can be made, which should also be considered as the scope of protection of the present invention.

Claims

1. A catalyst for the ammoxidation of light olefins, wherein the lattice oxygen concentration of the catalyst is α-Bi2Mo3O 12 The lattice oxygen concentration of α-Bi2Mo3O is 1.1~5 times that of 12 The CAS number is 13595-85-2; the raw materials for preparing the catalyst include an active component and a carrier that has been aged, the carrier includes silicon dioxide and a carrier additive, and the carrier additive is an inorganic base; The conditions of the aging treatment include: Temperature is 40~150℃; The time is 10 minutes to 10 hours; The general formula of the active component is Mo 11.0 Bi b Fe c D d E e O x , wherein D is selected from at least one of Li, Na, K, Rb and Cs; E is selected from at least one of Ca, Mg, La, Ce, Pr, Nd, Zr, Te, Sb, Ni, Cr, W and Nb; wherein b is in the range of 0.1 to 5.0; c is in the range of 0.1 to 5.0; d is in the range of 0.1 to 5.0; e is in the range of 0.1 to 5.0; and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst; The weight of the carrier additive is 0.1 to 5% by weight of the carrier.

2. The catalyst according to claim 1, characterized in that The lattice oxygen concentration of the catalyst is α-Bi2Mo3O 12 1.5~4.5 times the lattice oxygen concentration.

3. The catalyst according to claim 1, characterized in that The aging treatment conditions include: a temperature of 50-100° C.; and a time of 30 minutes to 5 hours.

4. The catalyst according to any one of claims 1 to 3, characterized in that The carrier additive is selected from at least one of potassium hydroxide, calcium hydroxide, magnesium hydroxide, cobalt hydroxide, nickel hydroxide, zirconium hydroxide and ammonium hydroxide.

5. The catalyst according to any one of claims 4, characterized in that The carrier additive is ammonium hydroxide.

6. The catalyst according to any one of claims 1 to 3, characterized in that The weight of the carrier is 35 to 65% by weight of the catalyst.

7. The method for preparing the light olefin ammoxidation catalyst according to any one of claims 1 to 6, comprising: Mixing a solution containing an active component precursor with a solution containing a carrier that has been aged, drying and calcining, wherein the carrier comprises silicon dioxide and a carrier additive, and the carrier additive is an inorganic base; The aging treatment conditions include: a temperature of 40 to 150° C.; and a time of 10 minutes to 10 hours.

8. The preparation method according to claim 7, characterized in that The solution containing the active component precursor includes a solution containing a Mo precursor and a solution containing a Bi precursor, a Fe precursor, a D precursor, and an E precursor, wherein D is selected from at least one of Li, Na, K, Rb, and Cs; and E is selected from at least one of Ca, Mg, La, Ce, Pr, Nd, Zr, Te, Sb, Ni, Cr, W, and Nb. and / or, the method for preparing the solution containing the carrier comprises: adding a carrier additive to a solution containing silica; And / or, the conditions for aging the solution containing the carrier include: a temperature of 40 to 150° C.; a time of 30 minutes to 5 hours; And / or, the calcination conditions include: a temperature of 500-680° C.; and a calcination time of 0.2-4 hours.

9. The preparation method according to claim 8, characterized in that The solution containing the Mo precursor is mixed with the solution containing the carrier that has been aged, and then mixed with the solution containing the Bi precursor, the Fe precursor, the D precursor, and the E precursor; and / or, the carrier additive is added to the silica-containing solution at a rate of 0.2 to 5 g / min; And / or, the calcination conditions include: a temperature of 550-650° C.; and a calcination time of 0.5-2.5 hours.

10. The preparation method according to claim 9, characterized in that The carrier additive is added to the silica-containing solution at a rate of 0.5 to 2 g / min.

11. The ammonia oxidation catalyst obtained by the preparation method according to any one of claims 7 to 10, wherein the lattice oxygen concentration of the catalyst is α-Bi2Mo3O 12 The lattice oxygen concentration of α-Bi2Mo3O is 1.1~5 times that of 12 The CAS number is 13595-85-2.

12. The catalyst according to claim 11, characterized in that The lattice oxygen concentration of the catalyst is α-Bi2Mo3O 12 1.5~4.5 times the lattice oxygen concentration.

13. A method for producing a nitrile compound, comprising: In the presence of the light olefin ammoxidation catalyst according to any one of claims 1 to 6 and 11 to 12 or the light olefin ammoxidation catalyst obtained by the preparation method according to any one of claims 7 to 10, a light olefin feedstock, ammonia and air are contacted to carry out an ammoxidation reaction.

14. The method according to claim 13, characterized in that The light olefin raw material is propylene and / or isobutylene; and / or, the molar ratio of the light olefin feedstock, ammonia, and air is 1:1.05-1.3:9.2-9.8; And / or, the reaction conditions include: temperature of 420-440° C., reaction pressure of 0.06-0.14 MPa; And / or, the propylene loading of the light olefin catalyst is 0.06~0.10 h -1 .

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