Method for preparing acetonitrile by dehydrogenation ammoniation of ethanol

Abstract

The invention discloses a method for preparing acetonitrile through ethanol dehydrogenation ammoniation. The method comprises the following steps: contacting and reacting a mixed raw material containing ethanol and ammonia gas with a catalyst to obtain a product containing acetonitrile, the catalyst comprises tin oxide, rare earth and petal-shaped aluminum oxide. The prepared catalyst is applied to acetonitrile preparation through ethanol dehydrogenation ammoniation, has the advantages of high acetonitrile selectivity, high stability and the like, and is better in stability compared with tin oxide, rare earth and amorphous alumina catalysts.

Description

Technical Field

[0001] The present application relates to a method for preparing acetonitrile by ethanol dehydrogenation and amination, belonging to the field of chemical engineering technology. Background Art

[0002] Acetonitrile is an organic chemical raw material with quite wide uses. Besides being used as an extractant for extracting butadiene and isoprene from olefins and paraffins in petrochemical industry, it is also widely used as a synthetic raw material for fine chemicals such as organic synthesis, medicine, pesticide, surfactant, dye, etc., and as a mobile phase solvent for thin layer chromatography, paper chromatography, spectroscopy, polarography and high performance liquid chromatography (HPLC). The latest application is used as a solvent for DNA synthesis and purification, a solvent for organic EL material synthesis, a cleaning solvent for electronic components such as chips, etc. These uses have very high requirements for the purity of acetonitrile (≥99.9%). Acetonitrile with a purity of ≥99.9% is quite popular in the market and has wide uses, and its proportion in consumption exceeds 66%.

[0003] At present, globally, acetonitrile is mainly recovered as a crude by-product in the production of acrylonitrile by ammoxidation of propylene. However, only 20 - 30 kg of acetonitrile can be obtained from 1 ton of acrylonitrile, and the purity is not high, especially it is very difficult to obtain acetonitrile with a purity of ≥99.9%. The production of acetonitrile by ethanol amination and dehydrogenation is a beneficial supplement to the source of acetonitrile. Compared with other methods for obtaining acetonitrile, the process for producing acetonitrile by ethanol amination and dehydrogenation is simple, has low energy consumption, high atom utilization rate, high selectivity for acetonitrile, few side reactions, low investment, and low operating cost, and can be industrialized;

[0004] The catalysts used for the production of acetonitrile by ethanol dehydrogenation and amination are divided into two categories: dehydrogenation / hydrogenation catalysts and dehydration catalysts. The dehydrogenation / hydrogenation catalysts mainly use Ni, Cu, Fe, Cr, Co, Rh, Zr, Pb, Ag, etc. as the main active components, and among them, cobalt and nickel are the most widely used. Usually, second and third components are also needed to be added as promoters, such as Cu, Na, Mg, Ca, etc. 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 selective and highly stable catalyst SnRe / FAl 2 O 3 (Re represents rare earth, F (Flow-like) represents petal-like) for the production of acetonitrile by ethanol dehydrogenation and amination.

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

[0007] The catalyst comprises tin oxide, rare earth and petal-like alumina.

[0008] Optionally, the mass of the tin oxide is 1.25 to 30 wt% of the mass of the catalyst, and the mass of the tin oxide is based on the mass of tin element.

[0009] Optionally, the mass of the tin oxide is any value among 1.25 wt%, 2.50 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt% or a range value between two values of the mass of the catalyst.

[0010] Optionally, the mass of the rare earth is 0.05 to 2.0 wt% of the mass of the catalyst.

[0011] Optionally, the mass of the rare earth is any value among 0.05 wt%, 0.10 wt%, 0.25 wt%, 0.5 wt%, 0.75 wt%, 1.0 wt%, 1.25 wt%, 1.50 wt%, 1.75 wt%, 2.0 wt% or a range value between two values of the mass of the catalyst.

[0012] Optionally, the preparation method of the catalyst is to knead, dry, and calcine petal-shaped alumina, rare earth nitrate, and a solution containing a tin salt precursor to obtain the catalyst;

[0013] Optionally, the tin-containing precursor is selected from SnCl 2 , SnCl 4 , SnSO 4 and at least one of them.

[0014] Optionally, the drying temperature is 80 to 100 °C, and the drying time is 3 to 6 h.

[0015] Optionally, the calcination temperature is selected from 500 to 1000 °C, and the calcination time is 2 to 4 h.

[0016] Optionally, the molar ratio of ammonia to ethanol is 2 to 8.

[0017] Optionally, the molar ratio of ammonia to ethanol is any value among 2, 3, 4, 5, 6, 7, 8 or a range value between two values.

[0018] Optionally, the mass space velocity of ethanol is 0.1 to 1.0 h -1 .

[0019] Optionally, the mass space velocity of ethanol is 0.1 h -1 , 0.2 h -1 , 0.3 h -1 , 0.4 h -1 , 0.5 h -1 , 0.6 h -1 , 0.7 h -1 , 0.8 h-1 、0.9 h -1 、1.0 h -1 Any value within or a range between two values among these.

[0020] Optionally, the reaction pressure is 0.1 - 0.5 MPa, and the reaction temperature is 350 - 500 °C.

[0021] Optionally, the reaction pressure is selected from any value within or a range between two values among 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, and 0.5 MPa.

[0022] Optionally, the reaction temperature is selected from any value within or a range between two values among 350 °C, 400 °C, 450 °C, 460 °C, 480 °C, and 550 °C.

[0023] The beneficial effects that can be produced by this application include:

[0024] The catalyst prepared by this application is used in the process of ethanol dehydrogenation amination to acetonitrile. Compared with the SnRe / NAl 2 O 3 (where N represents amorphous) catalyst, it shows higher acetonitrile selectivity and better stability. Specific Embodiments

[0025] The following details this application with reference to embodiments, but this application is not limited to these embodiments.

[0026] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0027] The analysis methods in the embodiments of this application are as follows:

[0028] The products are analyzed using gas chromatography Agilent 7890A.

[0029] In the embodiments of this application, the catalyst activity evaluation indicators, namely ethanol conversion rate, ammonia conversion rate, and acetonitrile selectivity, are all calculated based on mass:

[0030] Ethanol conversion rate:

[0031]

[0032] Ammonia conversion rate:

[0033]

[0034] Acetonitrile selectivity:

[0035]

[0036] In the above formulas, m represents mass.

[0037] Comparative Example 1

[0038] Weigh a certain amount of SnCl 2 ·2H 2 O and dissolve it in an aqueous solution of EDTA. The ratio of the solution to SnCl 2 is 3 ml / g (volume / mass), and the volume ratio of EDTA to water is 1 / 2. Place it in a sealed container and stir at 60°C for 6 hours. Then add a certain amount of amorphous alumina and lanthanum nitrate to the sealed container for kneading and forming. Dry it at 100°C for 3 hours and calcine it in a flowing air atmosphere at 800°C for 3 hours. The content of tin in the prepared catalyst Cat-A is 20 wt%, and the content of La is 0.50 wt%.

[0039] Comparative Example 2

[0040] Weigh a certain amount of SnCl 2 ·2H 2 O and dissolve it in an aqueous solution of EDTA. The ratio of the solution to SnCl 2 is 3 ml / g (volume / mass), and the volume ratio of EDTA to water is 1 / 2. Place it in a sealed container and stir at 60°C for 6 hours. Then add a certain amount of petal-shaped alumina to the sealed container for kneading and forming. Dry it at 100°C for 3 hours and calcine it in a flowing air atmosphere at 800°C for 3 hours. The content of tin in the prepared catalyst Cat-B is 20 wt%.

[0041] Example 1

[0042] Weigh a certain amount of SnCl 2 ·2H 2 O and dissolve it in an aqueous solution of EDTA. The ratio of the solution to SnCl 2 is 3 ml / g (volume / mass), and the volume ratio of EDTA to water is 1 / 2. Place it in a sealed container and stir at 60°C for 6 hours. Then add a certain amount of petal-shaped alumina and lanthanum nitrate to the sealed container for kneading and forming. Dry it at 100°C for 3 hours and calcine it in a flowing air atmosphere at 800°C for 3 hours. The content of tin in the prepared catalyst Cat-C is 20 wt%, and the content of La is 0.50 wt%.

[0043] Example 2

[0044] Weigh a certain amount of SnCl 4 ·5H 2 O and SnCl 2 ·2H 2 O and dissolve them in an aqueous solution of EDTA. Among them, SnCl 4 ·5H2 O and SnCl 2 ·2H 2 O has a mass ratio of 1 / 1, the ratio of the solution to (SnCl 2 +SnCl 4 ) is 2 ml / g (volume / mass), the volume ratio of EDTA to water is 1 / 1. It is placed in a sealed container and stirred at 70 °C for 4 hours. Then, a certain amount of petal-shaped alumina and cerium nitrate are added to the sealed container for kneading and forming, dried at 80 °C for 6 hours, and calcined in a flowing air atmosphere at 500 °C for 2 hours. The content of tin in the prepared catalyst Cat-D is 1.25 wt%, and the content of Ce is 0.05 wt%.

[0045] Example 3

[0046] According to the content of the active component tin, a certain amount of SnSO 4 is dissolved in the EDTA and aqueous solution. The ratio of the solution to SnSO 4 is 4 ml / g (volume / mass), the volume ratio of EDTA to water is 1 / 4. It is placed in a sealed container and stirred at 50 °C for 4 hours. Then, a certain amount of petal-shaped alumina and praseodymium nitrate are added to the sealed container for kneading and forming, dried at 90 °C for 5 hours, and calcined in a flowing air atmosphere at 1000 °C for 4 hours. The content of tin in the prepared catalyst Cat-E is 30 wt%, and the content of Pr is 2 wt%.

[0047] Example 4

[0048] According to the content of the active component tin, a certain amount of SnCl 4 ·5H 2 O is dissolved in the EDTA and aqueous solution. The ratio of the solution to SnCl 4 is 3 ml / g (volume / mass), the volume ratio of EDTA to water is 1 / 2. It is placed in a sealed container and stirred at 65 °C for 4 hours. Then, a certain amount of petal-shaped alumina and lanthanum nitrate are added to the sealed container for kneading and forming, dried at 85 °C for 4 hours, and calcined in a flowing air atmosphere at 750 °C for 3 hours. The content of tin in the prepared catalyst Cat-F is 10 wt%, and the content of La is 1 wt%.

[0049] Example 5

[0050] According to the content of the active component tin, a certain amount of SnCl 4 ·5H 2 O is dissolved in the EDTA and aqueous solution. The ratio of the solution to SnCl 4The ratio (volume / mass) is 3 ml / g, the volume ratio of EDTA to water is 1 / 2. It is placed in a sealed container and stirred at 65°C for 4 hours. Then, a certain amount of petal-shaped alumina and lanthanum nitrate are added to the sealed container for kneading and forming, dried at 85°C for 4 hours, and calcined in a flowing air atmosphere at 900°C for 3 hours. The content of tin in the prepared catalyst Cat-G is 15 wt%, and the content of La is 1.5 wt%.

[0051] Example 6

[0052] The catalytic performance of the catalysts prepared in Comparative Examples 1-2 for the dehydrogenation amination of ethanol to acetonitrile was evaluated on a self-made small reaction device. The reactor has a diameter of 9 mm and a catalyst loading of 4 g. Under ammonia gas conditions, it is heated to 430°C at a heating rate of 10°C / min, and ethanol is introduced. The evaluation durations are 3 h and 240 h respectively. The reaction conditions are: temperature is 430°C, pressure is 0.1 MPa, and the ethanol mass space velocity is 0.5 h -1 , and the molar ratio of ammonia to ethanol is 6:1. The products are analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.

[0053] Example 7

[0054] The catalytic performance of the catalyst prepared in Example 1 for the dehydrogenation amination of ethanol to acetonitrile was evaluated on a self-made small reaction device. The reactor has a diameter of 9 mm and a catalyst loading of 4 g. The reaction conditions are shown in Table 1. Under ammonia gas conditions, it is heated to 430°C at a heating rate of 10°C / min, and ethanol is introduced. The evaluation durations are 3 h and 240 h respectively. The reaction conditions are: temperature is 430°C, pressure is 0.1 MPa, and the ethanol mass space velocity is 0.5 h -1 , and the molar ratio of ammonia to ethanol is 6:1. The products are analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.

[0055] Example 8

[0056] The catalytic performance of the catalyst prepared in Example 2 for the dehydrogenation amination of ethanol to acetonitrile was evaluated on a self-made small reaction device. The reactor has a diameter of 9 mm and a catalyst loading of 4 g. The reaction conditions are shown in Table 1. Under ammonia gas conditions, it is heated to 500°C at a heating rate of 10°C / min, and ethanol is introduced. The evaluation durations are 3 h and 240 h respectively. The reaction conditions are: temperature is 500°C, pressure is 0.1 MPa, and the ethanol mass space velocity is 0.1 h -1 , and the molar ratio of ammonia to ethanol is 2:1. The products are analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.

[0057] Example 9

[0058] The reaction performance of the catalyst prepared in Example 3 was evaluated for the dehydrogenative amination of ethanol to acetonitrile on a self-made small-scale reaction device. The reactor had a diameter of 9 mm and a catalyst loading of 4 g. The reaction conditions were as shown in Table 1. Under ammonia conditions, the temperature was raised to 550 °C at a heating rate of 10 °C / min, and ethanol was introduced. The evaluation durations were 3 h and 240 h respectively. The reaction conditions were: temperature 550 °C, pressure 0.3 MPa, and ethanol mass space velocity 0.3 h -1 , and the molar ratio of ammonia to ethanol was 4:1. The products were analyzed by Agilent 7890 AGC, and the specific evaluation results are shown in Table 1.

[0059] Example 10

[0060] The reaction performance of the catalyst prepared in Example 4 was evaluated for the dehydrogenative amination of ethanol to acetonitrile on a self-made small-scale reaction device. The reactor had a diameter of 9 mm and a catalyst loading of 4 g. The reaction conditions were as shown in Table 1. Under ammonia conditions, the temperature was raised to 350 °C at a heating rate of 10 °C / min, and ethanol was introduced. The evaluation durations were 3 h and 240 h respectively. The reaction conditions were: temperature 350 °C, pressure 0.5 MPa, and ethanol mass space velocity 1.0 h -1 , and the molar ratio of ammonia to ethanol was 8:1. The products were analyzed by Agilent 7890 AGC, and the specific evaluation results are shown in Table 1.

[0061] Example 11

[0062] The reaction performance of the catalyst prepared in Example 5 was evaluated for the dehydrogenative amination of ethanol to acetonitrile on a self-made small-scale reaction device. The reactor had a diameter of 9 mm and a catalyst loading of 4 g. 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 durations were 3 h and 240 h respectively. The reaction conditions were: temperature 450 °C, pressure 0.2 MPa, and ethanol mass space velocity 0.8 h -1 , and the molar ratio of ammonia to ethanol was 8:1. The products were analyzed by Agilent 7890 AGC, and the specific evaluation results are shown in Table 1.

[0063] Table 1 Catalyst reaction performance

[0064] 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 0.30 0.50 0.20 <![CDATA[Ethanol mass space velocity (h -1 )]]> 0.5 0.5 0.5 0.1 0.3 1.0 0.8 Reaction temperature (°C) 430 430 430 500 550 350 450 Molar ratio of ammonia to alcohol 6 / 1 6 / 1 6 / 1 2 / 1 4 / 1 8 / 1 8 / 1 Ethanol conversion rate (%) / 3h* 97.95 97.92 98.96 99.98 99.96 99.89 99.69 Acetonitrile selectivity (%) / 3h 88.79 88.84 89.91 90.08 90.25 90.81 90.51 Ethanol conversion rate (%) / 240h** 87.95 92.92 98.90 99.92 99.93 99.79 99.70 Acetonitrile selectivity (%) / 240h 86.81 87.64 89.81 90.07 90.24 90.75 90.65

[0065] *: Reaction time is 3 h; **: Reaction time 240 h

[0066] The experimental results in Table 1 show that compared with SnLa / NAl 2 O 3 (Cat-A) and Sn / FAl 2 O 3 (Cat-B) catalysts, SnLa / FAl2 O 3 (Cat-C) had slightly higher initial ethanol conversion and acetonitrile selectivity (reaction time 3 h), with little difference. However, after continuous operation for 240 h, it was obvious that the reaction performance on Cat-A and Cat-B decreased significantly, while the changes in ethanol conversion and acetonitrile selectivity on the Cat-C catalyst were very small. Under the investigated reaction conditions, the prepared Cat-D, Cat-E, Cat-F, and Cat-G catalysts had excellent reaction performance.

[0067] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all 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, rare earth and petal-shaped alumina.

2. The method according to claim 1, characterized in that The mass of the tin oxide is 1.25-30wt% 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 mass of the rare earth is 0.05-2 wt % of the mass of the catalyst.

4. The method according to claim 1, characterized in that: The preparation method of the catalyst comprises the following steps: kneading, drying and calcining petal-shaped aluminum oxide, rare earth nitrate and a solution containing a tin salt precursor to obtain the catalyst.

5. The method according to claim 4, characterized in that The tin-containing precursor is selected from at least one of SnCl2, SnCl4, and SnSO4.

6. The method according to claim 4, characterized in that The drying temperature is 80-100° C., and the drying time is 3-6 hours.

7. The method according to claim 4, characterized in that The calcination temperature is selected from 500 to 1000° C., and the calcination time is 2 to 4 hours.

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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