A method for preparing acetonitrile by dehydrogenation and amination of ethanol

Abstract

The present application discloses a method for preparing acetonitrile by dehydrogenation and amination of ethanol. The method comprises contacting a mixed raw material containing ethanol and ammonia with a catalyst, reacting, and obtaining a product containing acetonitrile; the catalyst comprises tin oxide and aluminum oxide. The catalyst prepared in the present application is applied to preparing acetonitrile by dehydrogenation and amination of ethanol, and has the advantages of high ethanol conversion rate and high acetonitrile selectivity. Compared with conventional Co and Ni-based catalysts, tin is cheap and easy to obtain, and the catalyst is cheap.

Description

Technical Field

[0001] The present application relates to a method for preparing acetonitrile by dehydrogenation and amination of ethanol, and belongs to the technical field of chemical catalyst preparation. Background Art

[0002] Acetonitrile is an organic chemical raw material with a wide range of uses. In addition to being used as an extractant for extracting butadiene and isoprene from olefins and paraffins in petrochemicals, it is also widely used as a synthetic raw material for fine chemicals such as organic synthesis, medicine, pesticides, surfactants, dyes, and mobile phase solvents for thin layer chromatography, paper chromatography, spectroscopy, polarography, and high performance liquid chromatography (HPLC). The latest application is used as a DNA synthesis purification solvent, a solvent for the synthesis of organic EL materials, and a cleaning solvent for electronic components such as chips. These uses have high requirements for the purity of acetonitrile (≥99.9%). Acetonitrile with a purity of ≥99.9% is more popular in the market and has a wide range of uses, accounting for more than 66% of consumption.

[0003] Nowadays, acetonitrile is mainly recovered as a crude byproduct in the process of producing acrylonitrile from propylene ammoxidation worldwide. However, only 20-30 kg of acetonitrile can be obtained from 1 ton of acrylonitrile, and the purity is not high, especially it is difficult to achieve acetonitrile with a purity of ≥99.9%. The production of acetonitrile by ammoniating and dehydrogenating ethanol is a beneficial supplement to the source of acetonitrile. Compared with other methods for obtaining acetonitrile, the production of acetonitrile by ammoniating and dehydrogenating ethanol is simple in process, low in energy consumption, high in atomic utilization, high in acetonitrile selectivity, few side reactions, low in investment, low in operating costs, and can be industrialized;

[0004] The catalysts used in the production of acetonitrile by dehydrogenation and amination of ethanol are divided into two categories: dehydrogenation / hydrogenation catalysts and dehydration catalysts. Dehydrogenation / hydrogenation catalysts are mainly composed of Ni, Cu, Fe, Cr, Co, Rh, Zr, Pb and Ag as the main active components, among which cobalt and nickel are the most widely used. Usually, a second and third component are also required as a co-catalyst, such as Cu, Na, Mg, Ca and rare earth elements, and the elements of the catalyst are complex. Summary of the invention

[0005] The present application aims to develop a highly active and highly selective catalyst Sn / Al2O3 for the dehydrogenation of ethanol to produce acetonitrile.

[0006] According to one aspect of the present application, a method for preparing acetonitrile by dehydrogenation and amination of ethanol is provided, wherein a mixed raw material containing ethanol and ammonia is contacted with a catalyst to react to obtain a product containing acetonitrile;

[0007] The catalyst includes tin oxide and aluminum oxide.

[0008] Optionally, the mass of the tin oxide is 1.25-50 wt % of the mass of the catalyst, and the mass of the tin oxide is calculated as the mass of the tin element.

[0009] Optionally, the mass of the tin oxide is any value of 1.25wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt% of the catalyst mass, or a range between two values.

[0010] Optionally, the catalyst preparation method comprises kneading aluminum oxide and a solution containing a tin salt precursor, drying, and calcining in an inactive atmosphere to obtain the catalyst;

[0011] The solvent of the solution containing the tin salt precursor is ethylenediaminetetraacetic acid and water.

[0012] Optionally, the volume ratio of EDTA to water is 1:1-4.

[0013] Optionally, the volume ratio of ethylenediaminetetraacetic acid to water is any value of 1:1, 1:2, 1:3, 1:4, or a range value between two values.

[0014] Optionally, the tin-containing precursor is selected from at least one of SnCl2, SnCl4, and SnSO4.

[0015] Optionally, in the solution containing the tin salt precursor, the volume ratio of the mass of the tin salt precursor to the solvent is 1 g: 2 to 4 mL.

[0016] Optionally, in the solution containing the tin salt precursor, the volume ratio of the mass of the tin salt precursor to the solvent is any value of 1g:2mL, 1g:3mL, 1g:4mL, or a range value between two values.

[0017] Optionally, the drying temperature is 110-130° C., and the drying time is 6-12 hours.

[0018] Optionally, the calcination temperature is selected from 500 to 800° C., and the calcination time is 2 to 4 hours.

[0019] Optionally, the inert atmosphere is selected from at least one of nitrogen, helium and neon.

[0020] Optionally, the molar ratio of ammonia to ethanol is 2-8.

[0021] Optionally, the molar ratio of ammonia to ethanol is any value of 2, 3, 4, 5, 6, 7, 8, or a range value between two values.

[0022] Optionally, the mass space velocity of ethanol is 0.1 to 1.0 h -1 .

[0023] Optionally, the mass space velocity of the ethanol is 0.1h-1 、0.2h -1 、0.3h -1 、0.4h -1 , 0.5h -1 , 0.6h -1 、0.7h -1 、0.8h -1 、0.9h -1 , 1.0h -1 Any value or a range of values ​​between .

[0024] Optionally, the reaction pressure is 0.1-0.5 MPa, and the reaction temperature is 350-500°C.

[0025] Optionally, the reaction pressure is selected from any value among 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, or a range between two values.

[0026] Optionally, the reaction temperature is selected from any value of 350°C, 400°C, 450°C, 460°C, 480°C, 550°C, or a range between two values.

[0027] The beneficial effects of this application include:

[0028] The catalyst prepared in the present application is used in the process of ethanol dehydrogenation amination to produce acetonitrile, and shows high ethanol conversion rate and high acetonitrile selectivity. Compared with conventional Co and Ni-based catalysts, tin is cheap and easy to obtain, which reduces the price of the catalyst. DETAILED DESCRIPTION

[0029] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0030] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0031] The analysis method in the examples of this application is as follows:

[0032] The products were analyzed by gas chromatography (Agilent 7890A).

[0033] In the examples of the present application, the catalyst activity evaluation indexes, namely, ethanol conversion rate, ammonia conversion rate and acetonitrile selectivity are calculated based on mass:

[0034] Ethanol conversion rate:

[0035]

[0036] Ammonia conversion rate:

[0037]

[0038] Selectivity to acetonitrile:

[0039]

[0040] In the above formula, m represents mass.

[0041] Comparative Example 1

[0042] According to the content of active components cobalt and nickel, a certain amount of cobalt nitrate and nickel nitrate were weighed and dissolved in EDTA and aqueous solution, wherein the mass ratio of cobalt nitrate to nickel nitrate was 85 / 15, the ratio of solution to (cobalt nitrate + nickel nitrate) (volume / mass) was 3 ml / g, the volume ratio of EDTA to water was 1 / 2, placed in a sealed container and stirred at 60°C for 6 hours, then a certain amount of alumina was added to the sealed container for kneading and molding, dried at 120°C for 6 hours, and calcined at 700°C in a nitrogen atmosphere for 3 hours to obtain a catalyst Cat-A with a (cobalt + nickel) content of 20wt%.

[0043] Comparative Example 2

[0044] According to the content of active component tin, a certain amount of SnCl2·2H2O was weighed and dissolved in EDTA and aqueous solution, wherein the ratio of solution to SnCl2 (volume / mass) was 3 ml / g. The mixture was placed in a sealed container and stirred at 60°C for 6 hours. Then a certain amount of alumina was added to the sealed container and kneaded into a mixture. The mixture was dried at 120°C for 6 hours and calcined at 700°C in an air atmosphere for 3 hours to obtain a catalyst Cat-B with a tin content of 20 wt%.

[0045] Comparative Example 3

[0046] According to the content of tin as the active component, a certain amount of SnCl2·2H2O was weighed and dissolved in an aqueous solution, wherein the ratio of the solution to SnCl2 (volume / mass) was 3 ml / g. The mixture was placed in a sealed container and stirred at 60°C for 6 hours. Then a certain amount of alumina was added to the sealed container and kneaded into a shape. The mixture was dried at 120°C for 6 hours and calcined at 700°C in a nitrogen atmosphere for 3 hours to obtain a catalyst Cat-C with a tin content of 20 wt%.

[0047] Example 1

[0048] According to the content of active component tin, a certain amount of SnCl2·2H2O was weighed and dissolved in EDTA and aqueous solution, wherein the ratio of solution to SnCl2 (volume / mass) was 3 ml / g, and the volume ratio of EDTA to water was 1 / 2. The mixture was placed in a sealed container and stirred at 60°C for 6 hours. Then a certain amount of alumina was added to the sealed container and kneaded into shape. The mixture was dried at 120°C for 6 hours and calcined at 700°C in a nitrogen atmosphere for 3 hours to obtain a catalyst Cat-D with a tin content of 20 wt%.

[0049] Example 2

[0050] According to the content of active component tin, a certain amount of SnCl4·5H2O and SnCl2·2H2O are weighed and dissolved in EDTA and aqueous solution, wherein the mass ratio of SnCl4·5H2O and SnCl2·2H2O is 1 / 1, the ratio of solution to (SnCl2+SnCl4) (volume / mass) is 2ml / g, the volume ratio of EDTA and water is 1 / 1, placed in a sealed container and stirred at 70°C for 4 hours, and then a certain amount of alumina is added to the sealed container for kneading and molding, dried at 110°C for 12 hours, and calcined at 500°C in a nitrogen atmosphere for 4 hours to obtain a catalyst Cat-E with a tin content of 1.25wt%.

[0051] Example 3

[0052] According to the content of active component tin, a certain amount of SnSO4 is weighed and dissolved in EDTA and aqueous solution, wherein the ratio of solution to SnSO4 (volume / mass) is 4 ml / g, and the volume ratio of EDTA to water is 1 / 4. Place it in a closed container and stir at 50°C for 4 hours, then add a certain amount of alumina into the closed container and mix and knead it into shape, dry it at 130°C for 8 hours, and calcine it at 800°C in a nitrogen atmosphere for 2 hours to obtain a catalyst Cat-F with a tin content of 30wt%.

[0053] Example 4

[0054] According to the content of active component tin, a certain amount of SnCl4·5H2O was weighed and dissolved in EDTA and aqueous solution, wherein the ratio of solution to SnCl4 (volume / mass) was 3 ml / g, and the volume ratio of EDTA to water was 1 / 2. The mixture was placed in a sealed container and stirred at 65°C for 4 hours. Then a certain amount of alumina was added to the sealed container and kneaded into shape. The mixture was dried at 125°C for 10 hours and calcined at 750°C in a nitrogen atmosphere for 3 hours. The tin content of the obtained catalyst Cat-G was 50 wt%.

[0055] Example 5

[0056] The catalysts prepared in Comparative Examples 1 to 3 were used to evaluate the performance of ethanol dehydrogenation to acetonitrile in a self-made small-scale reactor. The reactor diameter was 9 mm, the catalyst loading was 4 g, and the temperature was raised to 430°C at a heating rate of 10°C / min under ammonia conditions. Ethanol was introduced and the evaluation time was 3 hours. The reaction conditions were: temperature of 430°C, pressure of 0.1 MPa, and ethanol mass space velocity of 0.5 h -1 , the molar ratio of ammonia to ethanol is 6: 1. The product was analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.

[0057] Example 6

[0058] The catalyst prepared in Example 1 was used to evaluate the performance of ethanol dehydrogenation to acetonitrile in a self-made small-scale reactor. The reactor diameter was 9 mm, the catalyst loading was 4 g, and the reaction conditions were as shown in Table 1. Under ammonia conditions, the temperature was raised to 430°C at a heating rate of 10°C / min, and ethanol was introduced. The evaluation time was 3 hours. The reaction conditions were: temperature of 430°C, pressure of 0.1 MPa, and ethanol mass space velocity of 0.5 h -1 , the molar ratio of ammonia to ethanol is 6: 1. The product was analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.

[0059] Example 7

[0060] The catalyst prepared in Example 2 was used to evaluate the performance of ethanol dehydrogenation to acetonitrile in a self-made small-scale reactor. The reactor diameter was 9 mm, the catalyst loading was 4 g, and the reaction conditions were as shown in Table 1. Under ammonia conditions, the temperature was raised to 500°C at a heating rate of 10°C / min, and ethanol was introduced. The evaluation time was 3 h. The reaction conditions were: temperature of 500°C, pressure of 0.1 MPa, and ethanol mass space velocity of 0.1 h -1 , the molar ratio of ammonia to ethanol is 2: 1. The product was analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.

[0061] Example 8

[0062] The catalyst prepared in Example 3 was used to evaluate the performance of ethanol dehydrogenation to acetonitrile in a self-made small-scale reactor. The reactor diameter was 9 mm, the catalyst loading was 4 g, and the reaction conditions were as shown in Table 1. Under ammonia conditions, the temperature was raised to 450°C at a heating rate of 10°C / min, and ethanol was introduced. The evaluation time was 3 hours. The reaction conditions were: temperature of 550°C, pressure of 0.3 MPa, and ethanol mass space velocity of 0.3 h -1 , the molar ratio of ammonia to ethanol is 4: 1. The product was analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.

[0063] Example 9

[0064] The catalyst prepared in Example 4 was used to evaluate the performance of ethanol dehydrogenation to acetonitrile in a self-made small-scale reactor. The reactor diameter was 9 mm, the catalyst loading was 4 g, and the reaction conditions were as shown in Table 1. Under ammonia conditions, the temperature was raised to 400°C at a heating rate of 10°C / min, and ethanol was introduced. The evaluation time was 3 hours. The reaction conditions were: temperature of 350°C, pressure of 0.5 MPa, and ethanol mass space velocity of 1.0 h -1 , the molar ratio of ammonia to ethanol is 8: 1. The product was analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.

[0065] Table 1 Catalyst reaction performance

[0066] Cat-A Cat-B Cat-C Cat-D Cat-E Cat-F Cat-G Reaction pressure (MPa) 0.10 0.10 0.10 0.10 0.10 0.30 0.50 <![CDATA[Weight hourly space velocity of ethanol (h -1 )]]> 0.5 0.5 0.5 0.5 0.1 0.3 1.0 Reaction temperature (℃) 430 430 430 430 500 550 350 Amine alcohol molar ratio 6 / 1 6 / 1 6 / 1 6 / 1 2 / 1 4 / 1 8 / 1 Ethanol conversion rate (%) 97.95 97.92 98.96 99.93 99.98 99.95 99.99 Ammonia conversion rate (%) 14.13 14.69 15.03 15.97 16.09 16.08 16.24 Acetonitrile selectivity (%) 82.89 82.64 83.81 88.84 90.08 90.25 90.81

[0067] The experimental results in Table 1 show that compared with the cobalt-based / nickel-based (EDTA+water solvent) alumina catalyst (Cat-A) prepared in a nitrogen atmosphere, the air-calcined tin-based (EDTA+water solvent) alumina (Cat-B), and the nitrogen-calcined tin-based (water solvent) alumina (Cat-C), the acetonitrile selectivity on the tin-based (EDTA+water solvent) alumina catalyst (Cat-D) prepared in a nitrogen atmosphere is significantly higher. Under the reaction conditions examined, the reaction performance of the prepared Cat-E, Cat-F and Cat-G catalysts is excellent.

[0068] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing acetonitrile by dehydrogenation of ethanol, characterized in that: The mixed raw material containing ethanol and ammonia is contacted with a catalyst to react and obtain a product containing acetonitrile; The catalyst includes tin oxide and aluminum oxide.

2. The method according to claim 1, characterized in that The mass of the tin oxide is 1.25-50wt% of the mass of the catalyst, and the mass of the tin oxide is calculated based on the mass of the tin element.

3. The method according to claim 1, characterized in that The preparation method of the catalyst comprises kneading aluminum oxide and a solution containing a tin salt precursor, drying, and calcining in an inactive atmosphere to obtain the catalyst; The solvent of the solution containing the tin salt precursor is ethylenediaminetetraacetic acid and water.

4. The method according to claim 3, characterized in that The volume ratio of EDTA to water is 1:1-4.

5. The method according to claim 3, characterized in that: The tin-containing salt precursor is SnCl4; In the solution containing the tin salt precursor, the volume ratio of the mass of the tin salt precursor to the solvent is 1 g: 2 to 4 mL.

6. The method according to claim 3, characterized in that The drying temperature is 110-130° C., and the drying time is 6-12 hours.

7. The method according to claim 3, characterized in that The calcination temperature is selected from 500 to 800° C., and the calcination time is 2 to 4 hours; The inert atmosphere is selected from at least one of nitrogen, helium and neon.

8. The method according to claim 1, characterized in that The molar ratio of ammonia to ethanol is 2-8.

9. The method according to claim 1, characterized in that: The mass space velocity of the ethanol is 0.1 to 1.0 h -1 .

10. The method according to claim 1, characterized in that: The reaction pressure is 0.1-0.5 MPa, and the reaction temperature is 350-500°C.

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