Composite metal oxide catalyst, method for preparing the same, and use thereof

Abstract

This application discloses a composite metal oxide catalyst, its preparation method, and its application. The composite metal oxide catalyst comprises a support and metal oxides supported on the surface of the support; the metal oxides include metal oxide I, metal oxide II, and metal oxide III; metal oxide I is selected from at least one of manganese oxide, ferrous oxide, cobalt oxide, nickel oxide, copper oxide, and zinc oxide; metal oxide II is selected from at least one of magnesium oxide, calcium oxide, strontium oxide, and barium oxide; metal oxide III is selected from at least one of lithium oxide, sodium oxide, and potassium oxide; the loading amount of metal oxide I is 0.1–20 wt%, the loading amount of metal oxide II is 0.01–5 wt%, the loading amount of metal oxide III is 0.01–5 wt%, and the remainder is the support.

Description

Technical Field

[0001] This application relates to a composite metal oxide catalyst, its preparation method, and its application, belonging to the field of catalysts. Background Technology

[0002] Acetonitrile is an important chemical used in the production of pesticides, pharmaceuticals, dyes, and other products. The main production methods for acetonitrile include acetic acid ammoniation, acetylene ammoniation, ethanol ammoniation, and propylene ammoniation as a byproduct. Currently, the primary method for industrial acetonitrile production is the propylene ammoniation byproduct method, where acetonitrile is produced as a byproduct of propylene ammoniation. This method limits acetonitrile production due to the limited output of acrylonitrile. Therefore, developing new and economical acetonitrile production methods remains a challenge. Acetate ester ammoniation to acetonitrile is a promising route due to its mild conditions, environmental friendliness, and economic efficiency. Currently, the conversion rate and selectivity of acetonitrile produced by acetate ester ammoniation need further improvement. Furthermore, since acetate ester ammoniation produces alcohols as byproducts, these alcohols can be recycled to produce acetate esters. Therefore, to improve the overall economic efficiency of the route, the selectivity of the byproduct alcohols also needs further improvement. Thus, improving the acetate ester conversion rate and the selectivity of acetonitrile and alcohols is crucial for making the acetate ester ammoniation method more economical and enabling industrial application. Summary of the Invention

[0003] According to one aspect of this application, a composite metal oxide catalyst is provided, the composite metal oxide catalyst being composed of a support and a metal oxide supported on the surface of the support;

[0004] The metal oxides include metal oxide I, metal oxide II, and metal oxide III;

[0005] The metal oxide I is selected from at least one of manganese oxide, ferrous oxide, cobalt oxide, nickel oxide, copper oxide, and zinc oxide;

[0006] The metal oxide II is selected from at least one of magnesium oxide, calcium oxide, strontium oxide and barium oxide;

[0007] The metal oxide III is selected from at least one of lithium oxide, sodium oxide, and potassium oxide;

[0008] In the composite metal oxide catalyst, the loading of metal oxide I is 0.1–20 wt%, the loading of metal oxide II is 0.01–5 wt%, the loading of metal oxide III is 0.01–5 wt%, and the remainder is a support.

[0009] The carrier is selected from at least one of silicon oxide, aluminum oxide, titanium oxide, and zirconium oxide.

[0010] According to another aspect of this application, a method for preparing the above-mentioned composite metal oxide catalyst is provided, comprising the following steps:

[0011] (1) The support precursor is mixed with metal oxide I and metal oxide II to obtain a mixture, an acid solution containing alcohol is added, kneaded, shaped, dried I, and calcined I to obtain the catalyst precursor.

[0012] (2) An equal volume of aqueous solution containing metal oxide III precursor is impregnated onto the catalyst precursor, dried (II), and calcined (II) to obtain the composite metal oxide catalyst.

[0013] Optionally, the following steps are included:

[0014] 1) Mix the carrier precursor with metal oxide I and metal oxide II evenly to obtain mixture 1, then add acidic solution and stir and knead to form the mixture into spheres or strips, dry and calcine to obtain catalyst precursor; 2) Impregnate the above-formed catalyst precursor with an equal volume of alkali metal salt, dry and calcine to obtain catalyst for producing acetonitrile.

[0015] The carrier precursor is selected from at least one of silica sol, water glass, silica, tetraethyl silicate, γ-alumina, boehmite, aluminum isopropoxide, titanium dioxide, and zirconium dioxide.

[0016] The alcohol is selected from at least one of ethanol, propanol, and butanol;

[0017] The acid is selected from organic acids and inorganic acids;

[0018] The organic acid is selected from at least one of acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, and benzoic acid;

[0019] The inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid, and nitric acid;

[0020] In the acid solution containing alcohol, the mass fraction of alcohol is 0.1-10 wt%, the mass fraction of organic acid is 0.1-20 wt%, the mass fraction of inorganic acid is 0.1-30 wt%, and the remainder is water;

[0021] The mass ratio of the mixture to the acid solution containing alcohol is 3 to 10:1.

[0022] The temperature of the drying process I is 100–140°C;

[0023] The drying time for step I is 12–36 hours;

[0024] The temperature of the calcination I is 300–600°C;

[0025] The roasting time for the first stage is 3 to 24 hours.

[0026] The metal oxide III precursor is selected from at least one of lithium nitrate, sodium nitrate, potassium nitrate, lithium chloride, sodium chloride, and potassium chloride.

[0027] The temperature of the drying II process is 100–140°C;

[0028] The drying time for step II is 12–36 hours;

[0029] The temperature of calcination II is 300–600°C;

[0030] The roasting time for the second stage is 3 to 24 hours.

[0031] According to another aspect of this application, a method for producing acetonitrile by reacting acetate with ammonia is provided, comprising the following steps:

[0032] The raw materials containing acetate and ammonia are contacted with a catalyst and reacted to obtain a product containing acetonitrile.

[0033] The catalyst is the aforementioned composite metal oxide catalyst.

[0034] The acetate is selected from at least one of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and cyclohexyl acetate;

[0035] In the raw materials, the space velocity of the acetate is 0.1-3 h⁻¹. -1 ;

[0036] In the raw materials, the molar ratio of ammonia to acetate is 1 to 60:1.

[0037] The reaction temperature is 200–400°C;

[0038] The reaction is carried out at a pressure of 0.1–1 MPa.

[0039] The beneficial effects that this application can produce include:

[0040] 1) The catalyst for producing acetonitrile provided in this application can be used in the reaction of acetate with ammonia to produce acetonitrile. The conversion rate of acetate can reach more than 99%, and the selectivity of acetonitrile can reach more than 99.5%.

[0041] 2) The catalyst preparation method for producing acetonitrile provided in this application is simple, easy to scale up, and the selectivity of by-product alcohols can reach more than 99.5%, which is economical. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments, but this application is not limited to these embodiments. Unless otherwise specified, the raw materials used in the embodiments of this application were all purchased commercially.

[0043] In the embodiments of this application, the conversion rate and selectivity are calculated as follows:

[0044] Conversion rate of acetate = (1 - moles of acetate in product / moles of acetate in feed) * 100%

[0045] Selectivity of acetonitrile = (moles of acetonitrile in the product / (moles of acetate in the feed - moles of acetate in the product)) * 100%

[0046] Alcohol selectivity = (moles of alcohol in product / (moles of acetate in feed - moles of acetate in product)) * 100%

[0047] Example 1

[0048] 158.2 g of 30% silica sol, 2.5 g of manganese monoxide, and 0.005 g of magnesium oxide were mixed evenly and then added to 16.1 g of a mixed solution of ethanol-acetic acid-hydrochloric acid, with concentrations of 1%, 5%, and 30% for ethanol, acetic acid, and hydrochloric acid, respectively. After mixing evenly, the mixture was shaped into spheres, dried at 100°C for 12 hours, and calcined at 300°C for 24 hours to obtain the catalyst precursor. 0.12 g of lithium nitrate was prepared into an aqueous solution and impregnated onto the catalyst precursor by an equal volume. The solution was then dried at 100°C for 12 hours and calcined at 300°C for 24 hours to obtain catalyst A. Catalyst A was loaded into a tubular reactor and reacted with methyl acetate and ammonia gas at a reaction temperature of 350°C, a pressure of 0.1 MPa, and a methyl acetate space velocity of 1 h⁻¹. -1 The molar ratio of ammonia to methyl acetate was 10:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0049] Example 2

[0050] 128.4 g of 35% water glass, 0.05 g of ferrous oxide, and 2.5 g of calcium oxide were mixed thoroughly and then added to a 16.4 g solution of propanol-propionic acid-sulfuric acid, where the concentrations of propanol, propionic acid, and sulfuric acid were 5%, 0.1%, and 20%, respectively. After thorough mixing, the mixture was shaped into strips, dried at 120°C for 15 hours, and calcined at 350°C for 12 hours to obtain the catalyst precursor. 3.4 g of sodium nitrate was prepared into an aqueous solution and impregnated onto the catalyst precursor in equal volume. The solution was then dried at 120°C for 15 hours and calcined at 350°C for 12 hours to obtain catalyst B. Catalyst B was loaded into a tubular reactor and reacted with ethyl acetate and ammonia gas at a reaction temperature of 400°C, a pressure of 0.1 MPa, and an ethyl acetate space velocity of 3 h⁻¹. -1 The molar ratio of ammonia to ethyl acetate was 40:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0051] Example 3

[0052] 46.5g of silica, 1.5g of cobalt oxide, and 1g of strontium oxide were mixed evenly and then added to a mixed solution of butanol, butyric acid, and nitric acid, with concentrations of 0.1%, 2%, and 20%, respectively. After thorough mixing, the mixture was shaped into spheres, dried at 140℃ for 24 hours, and calcined at 400℃ for 15 hours to obtain the catalyst precursor. 1.1g of potassium nitrate was prepared into an aqueous solution and impregnated onto the catalyst precursor in equal volume. The solution was then dried at 140℃ for 24 hours and calcined at 400℃ for 15 hours to obtain catalyst C. Catalyst C was loaded into a tubular reactor and reacted with methyl acetate and ammonia gas at 300℃ and 0.5MPa, with a methyl acetate space velocity of 0.1 h⁻¹. -1 The molar ratio of ammonia to methyl acetate was 1:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0053] Example 4

[0054] 276.1 g of tetraethyl silicate, 10 g of nickel oxide, and 1.5 g of barium oxide were mixed evenly and then added to a 9 g mixed solution of ethanol-oxalic acid-hydrochloric acid, with concentrations of 10%, 1%, and 30% for ethanol, oxalic acid, and hydrochloric acid, respectively. After thorough mixing, the mixture was shaped into spheres, dried at 100 °C for 36 hours, and calcined at 450 °C for 6 hours to obtain the catalyst precursor. 2.1 g of lithium chloride was prepared into an aqueous solution and impregnated onto the catalyst precursor by an equal volume. The solution was then dried at 100 °C for 36 hours and calcined at 450 °C for 6 hours to obtain catalyst D. Catalyst D was loaded into a tubular reactor and propyl acetate and ammonia gas were introduced to react with the catalyst at a reaction temperature of 250 °C, a pressure of 0.1 MPa, and a propyl acetate space velocity of 1 h⁻¹. -1 The molar ratio of ammonia to propyl acetate was 60:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0055] Example 5

[0056] 49g of γ-alumina, 0.5g of copper oxide, and 0.5g of magnesium oxide were mixed evenly and then added to a mixed solution of ethanol-malonic acid-sulfuric acid, with concentrations of 6%, 10%, and 10% for ethanol, malonic acid, and sulfuric acid, respectively. After thorough mixing, the mixture was shaped into spheres, dried at 120℃ for 12 hours, and calcined at 500℃ for 4 hours to obtain the catalyst precursor. 0.05g of sodium chloride was prepared into an aqueous solution and impregnated onto the catalyst precursor by an equal volume. The solution was then dried at 120℃ for 12 hours and calcined at 500℃ for 4 hours to obtain catalyst E. Catalyst E was loaded into a tubular reactor and reacted with butyl acetate and ammonia gas at a reaction temperature of 200℃, a pressure of 0.1MPa, and a butyl acetate space velocity of 0.5h⁻¹.-1 The molar ratio of ammonia to butyl acetate was 60:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0057] Example 6

[0058] 60.4 g of boehmite, 6 g of zinc oxide, and 1.5 g of calcium oxide were mixed evenly and then added to a mixed solution of propanol, benzoic acid, and nitric acid, with concentrations of 8%, 3%, and 30%, respectively. After thorough mixing, the mixture was shaped into spheres, dried at 140 °C for 24 hours, and calcined at 550 °C for 6 hours to obtain the catalyst precursor. 0.2 g of potassium chloride was prepared into an aqueous solution and impregnated onto the catalyst precursor in equal volume. The solution was then dried at 140 °C for 24 hours and calcined at 550 °C for 6 hours to obtain catalyst F. Catalyst F was loaded into a tubular reactor and cyclohexyl acetate and ammonia were introduced to react with the catalyst. The reaction temperature was 250 °C, the pressure was 0.1 MPa, and the cyclohexyl acetate space velocity was 2 h⁻¹. -1 The molar ratio of ammonia to cyclohexyl acetate was 30:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0059] Example 7

[0060] 314g of aluminum isopropoxide, 7.5g of manganese monoxide, and 0.5g of strontium oxide were mixed evenly and then added to a 40g mixed solution of butanol-propionic acid-nitric acid, with concentrations of 1%, 10%, and 20% for butanol, propionic acid, and nitric acid, respectively. After thorough mixing, the mixture was shaped into strips, dried at 120℃ for 36 hours, and calcined at 600℃ for 3 hours to obtain the catalyst precursor. 0.5g of sodium chloride was prepared into an aqueous solution and impregnated onto the catalyst precursor in equal volume. The solution was then dried at 120℃ for 36 hours and calcined at 600℃ for 3 hours to obtain catalyst G. Catalyst G was loaded into a tubular reactor and methyl acetate and ammonia gas were introduced to react with the catalyst at a reaction temperature of 300℃, a pressure of 0.1MPa, and a methyl acetate space velocity of 1 h⁻¹. -1 The molar ratio of ammonia to methyl acetate was 20:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0061] Example 8

[0062] 38.5g of titanium dioxide, 10g of ferrous oxide, and 1.5g of magnesium oxide were mixed evenly and then added to a 10g mixed solution of ethanol-acetic acid-hydrochloric acid. The concentrations of ethanol, acetic acid, and hydrochloric acid were 10%, 20%, and 0.1%, respectively. After mixing evenly, the mixture was shaped into spheres, dried at 120℃ for 12 hours, and calcined at 550℃ for 6 hours to obtain the catalyst precursor. 0.07g of lithium chloride was prepared into an aqueous solution and impregnated onto the catalyst precursor by an equal volume. The solution was dried at 120℃ for 12 hours and calcined at 550℃ for 6 hours to obtain catalyst H. Catalyst H was loaded into a tubular reactor and methyl acetate and ammonia gas were introduced to react with the catalyst. The reaction temperature was 350℃, the pressure was 0.3MPa, and the methyl acetate space velocity was 1h⁻¹. -1 The molar ratio of ammonia to methyl acetate was 15:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0063] Example 9

[0064] 44.5g of zirconium dioxide, 5g of cobalt oxide, and 1g of calcium oxide were mixed evenly and then added to a 16.7g mixed solution of propanol-propionic acid-nitric acid, with concentrations of 4%, 5%, and 30% for propanol, propionic acid, and nitric acid, respectively. After thorough mixing, the mixture was shaped into spheres, dried at 120℃ for 24 hours, and calcined at 550℃ for 4 hours to obtain the catalyst precursor. 0.12g of lithium nitrate was prepared into an aqueous solution and impregnated onto the catalyst precursor by an equal volume. The solution was then dried at 120℃ for 24 hours and calcined at 550℃ for 4 hours to obtain catalyst I. Catalyst I was loaded into a tubular reactor and reacted with ethyl acetate and ammonia gas at a reaction temperature of 300℃, a pressure of 0.1MPa, and an ethyl acetate space velocity of 0.5h⁻¹. -1 The molar ratio of ammonia to ethyl acetate was 10:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0065] Comparative Example 1

[0066] 158.2 g of 30% silica sol, 2.5 g of manganese monoxide, and 0.005 g of magnesium oxide were mixed evenly, and then 16.1 g of 30% hydrochloric acid solution was added. After mixing evenly, the mixture was shaped into spheres, dried at 100℃ for 12 hours, and calcined at 300℃ for 24 hours to obtain catalyst J. Catalyst J was loaded into a tubular reactor and methyl acetate and ammonia gas were introduced to react with the catalyst. The reaction temperature was 350℃, the pressure was 0.1 MPa, and the methyl acetate space velocity was 1 h⁻¹. -1 The molar ratio of ammonia to methyl acetate was 10:1. The composition of the reaction products was analyzed by gas chromatography, and the calculated reaction results are listed in Table 1.

[0067] Table 1 Results of acetate amination reaction

[0068] Serial Number Conversion rate % Acetonitrile selectivity % Alcohol selectivity % Example 1 99.3 99.6 99.5 Example 2 99.4 99.5 99.7 Example 3 99.2 99.7 99.6 Example 4 99.1 99.8 99.8 Example 5 99.5 99.6 99.7 Example 6 99.4 99.7 99.7 Example 7 99.2 99.7 99.6 Example 8 99.6 99.8 99.5 Example 9 99.4 99.6 99.8 Comparative Example 1 99.5 93.3 91.4

[0069] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A composite metal oxide catalyst, characterized in that, The composite metal oxide catalyst consists of a support and a metal oxide supported on the surface of the support; The metal oxides include metal oxide I, metal oxide II, and metal oxide III; The metal oxide I is selected from at least one of manganese oxide, ferrous oxide, cobalt oxide, nickel oxide, copper oxide, and zinc oxide; The metal oxide II is selected from at least one of magnesium oxide, calcium oxide, strontium oxide and barium oxide; The metal oxide III is selected from at least one of lithium oxide, sodium oxide, and potassium oxide; In the composite metal oxide catalyst, the loading of metal oxide I is 0.1–20 wt%, the loading of metal oxide II is 0.01–5 wt%, the loading of metal oxide III is 0.01–5 wt%, and the remainder is a support.

2. The composite metal oxide catalyst according to claim 1, characterized in that, The carrier is selected from at least one of silicon oxide, aluminum oxide, titanium oxide, and zirconium oxide.

3. A method for preparing the composite metal oxide catalyst according to any one of claims 1 or 2, characterized in that, Includes the following steps: (1) The support precursor is mixed with metal oxide I and metal oxide II to obtain a mixture, an acid solution containing alcohol is added, kneaded, shaped, dried I, and calcined I to obtain the catalyst precursor. (2) An equal volume of aqueous solution containing metal oxide III precursor is impregnated onto the catalyst precursor, dried (II), and calcined (II) to obtain the composite metal oxide catalyst.

4. The preparation method according to claim 3, characterized in that, The carrier precursor is selected from at least one of silica sol, water glass, silica, tetraethyl silicate, γ-alumina, boehmite, aluminum isopropoxide, titanium dioxide, and zirconium dioxide. The alcohol is selected from at least one of ethanol, propanol, and butanol; The acid is selected from organic acids and inorganic acids; The organic acid is selected from at least one of acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, and benzoic acid; The inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid, and nitric acid; In the acid solution containing alcohol, the mass fraction of alcohol is 0.1-10 wt%, the mass fraction of organic acid is 0.1-20 wt%, the mass fraction of inorganic acid is 0.1-30 wt%, and the remainder is water; The mass ratio of the mixture to the acid solution containing alcohol is 3 to 10:

1.

5. The preparation method according to claim 3, characterized in that, The temperature of the drying process I is 100–140°C; The drying time for step I is 12–36 hours; The temperature of the calcination I is 300–600°C; The roasting time for the first stage is 3 to 24 hours.

6. The preparation method according to claim 3, characterized in that, The metal oxide III precursor is selected from at least one of lithium nitrate, sodium nitrate, potassium nitrate, lithium chloride, sodium chloride, and potassium chloride.

7. The preparation method according to claim 3, characterized in that, The temperature of the drying II process is 100–140°C; The drying time for step II is 12–36 hours; The temperature of calcination II is 300–600°C; The roasting time for the second stage is 3 to 24 hours.

8. A method for producing acetonitrile by reacting acetate with ammonia, characterized in that, Includes the following steps: The raw materials containing acetate and ammonia are contacted with a catalyst and reacted to obtain a product containing acetonitrile. The catalyst is the composite metal oxide catalyst according to any one of claims 1 or 2.

9. The method according to claim 8, characterized in that, The acetate is selected from at least one of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and cyclohexyl acetate; In the raw materials, the space velocity of the acetate is 0.1-3 h⁻¹. -1 ; In the raw materials, the molar ratio of ammonia to acetate is 1 to 60:

1.

10. The method according to claim 8, characterized in that, The reaction temperature is 200–400°C; The reaction is carried out at a pressure of 0.1–1 MPa.