Method for purifying coal-based ethanol and method for preparing acetonitrile by promoting coal-based ethanol dehydroamination
By purifying coal-based ethanol with solid adsorbent composition, the problem of impurities affecting the reaction performance of the catalyst is solved, and the effect of efficient preparation of high-purity acetonitrile is achieved.
Patent Information
- Application Number
- CN202410148055.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-01
- Publication Date
- 2025-08-01
AI Technical Summary
The prior art is difficult to effectively remove trace ester compounds, polymers and pyridine bases in coal-based ethanol, which affects the reaction performance of the catalyst, making it difficult for the acetonitrile purity to reach ≥99.9%.
The coal-based ethanol is purified by solid adsorbent compositions (activated carbon and molecular sieve, silica gel, white clay, etc.), impurities are removed by physical adsorption method, and then acetonitrile is dehydrogenated with ammonia under a catalyst.
The purification effect of coal-based ethanol is improved, so that the purified ethanol exhibits high ethanol conversion and high acetonitrile selectivity on the catalyst, meeting the purity requirement of ≥99.9%.
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Abstract
Description
Technical Field
[0001] The present application relates to a purification method for coal-based ethanol and a method for promoting the dehydrogenation amination of coal-based ethanol to acetonitrile, belonging to the technical field of application of chemical adsorbents. Background Art
[0002] Acetonitrile is an organic chemical raw material with quite wide applications. Besides being used as an extraction agent 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 as a solvent for DNA synthesis purification, a solvent for organic EL material synthesis, a cleaning solvent for electronic components such as chips, etc. These applications 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 applications, and its proportion in the consumption volume exceeds 66%.
[0003] Currently, globally, acetonitrile is mainly recovered as a crude by-product during 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 dehydrogenation amination of ethanol is a beneficial supplement to the source of acetonitrile. Compared with other methods for obtaining acetonitrile, the process for producing acetonitrile by dehydrogenation amination of ethanol 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. At present, the output of bio-ethanol is limited, while the successful development and industrial production of coal-based ethanol (derived from coal, coke oven gas and steel mill tail gas) (> 3 million tons / year) provides a raw material guarantee for this project.
[0004] The catalysts used for the production of acetonitrile by dehydrogenation amination of ethanol 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.
[0005] For the process of producing acetonitrile by dehydrogenation amination of coal-based ethanol, impurities such as ester compounds, polymers and pyridine bases in coal-based ethanol seriously affect the reaction performance of the catalyst (as shown in Table 1), and generally need to be removed to below 50 ppm. How to remove trace ester compounds, polymers and pyridine bases and other impurities in coal-based ethanol is a meaningful research topic. Summary of the Invention
[0006] The object of the present invention is to provide a method for removing trace ester compounds, polymers, pyridine bases and other impurities from coal-based ethanol by physical adsorption, and dehydrogenating and aminating the qualified coal-based ethanol (wherein the ester compounds, polymers, pyridine bases, etc. < 50 ppm) after purification to produce acetonitrile. Specifically, a solid adsorbent is developed to purify coal-based ethanol, and the purified ethanol and ammonia mixed raw material is reacted with a catalyst to obtain a product containing acetonitrile.
[0007] In one aspect of the present application, a purification method of coal-based ethanol is provided, and the purification method includes:
[0008] Contacting coal-based ethanol I containing impurities with a solid adsorbent, adsorbing, to obtain purified coal-based ethanol II;
[0009] The solid adsorbent is composed of solid adsorbent A and solid adsorbent B;
[0010] The solid adsorbent A is activated carbon and / or resin;
[0011] The solid adsorbent B is selected from at least one of molecular sieve, silica gel, clay, and diatomaceous earth.
[0012] Optionally, the impurities include ester compounds, polymers, and pyridine bases;
[0013] In the coal-based ethanol II, the total concentration of ester compounds, polymers, and pyridine bases < 50 ppm.
[0014] Optionally, in the solid adsorbent, the volume ratio of solid adsorbent A to solid adsorbent B is 0.2 - 1:1.
[0015] Optionally, in the solid adsorbent, the volume ratio of solid adsorbent A to solid adsorbent B independently selects any value from 0.2:1, 0.4:1, 0.5:1, 0.75:1, 1 or the range value between any two of the above.
[0016] Optionally, in the solid adsorbent, the volume ratio of solid adsorbent A to solid adsorbent B is 0.3 - 0.9.
[0017] Optionally, the conditions for adsorption are: the adsorption temperature is 5 - 30 °C; the adsorption pressure is 0.1 - 3.0 Mpa; the mass space velocity of coal-based ethanol I is 0.2 - 1 h -1 。
[0018] Optionally, the adsorption temperature independently selects any value from 5 °C, 10 °C, 15 °C, 25 °C, 30 °C or the range value between any two of the above.
[0019] Optionally, the adsorption pressure is independently selected from any value among 0.1 Mpa, 0.3 Mpa, 0.5 Mpa, 1 Mpa, 2 Mpa, 2.8 Mpa, 3.0 Mpa or a range value between any two of the above.
[0020] Optionally, the mass hourly space velocity of the coal-based ethanol I is independently selected from any value among 0.2 h -1 , 0.3 h -1 , 0.4 h -1 , 0.5 h. -1 , 0.8 h -1 , 1 h -1 or a range value between any two of the above.
[0021] Optionally, the conditions for the adsorption are: the adsorption temperature is 10 - 25 °C; the adsorption pressure is 0.3 - 2.8 Mpa; the mass hourly space velocity of the coal-based ethanol I is 0.4 - 0.8 h -1 .
[0022] In another aspect of the present application, a method for promoting the dehydrogenation amination of coal-based ethanol to acetonitrile is provided. The method includes:
[0023] Contacting and reacting a raw material containing the coal-based ethanol and ammonia with a catalyst to obtain a product containing acetonitrile; wherein, the coal-based ethanol is the purified coal-based ethanol II obtained by the above purification method. The catalyst used is self-made 20 wt% Sn / Al2O3 or 30 wt% Sn / Al2O3.
[0024] Optionally, for the dehydrogenation amination of the purified coal-based ethanol II to acetonitrile, the molar ratio of ammonia to coal-based ethanol is 2 - 8.
[0025] Optionally, the molar ratio of ammonia to coal-based ethanol is independently selected from any value among 2, 3, 4, 5, 6, 7, 8 or a range value between any two of the above.
[0026] Optionally, the mass hourly space velocity of the coal-based ethanol is 0.1 - 1.0 h -1 .
[0027] Optionally, the mass hourly space velocity of the coal-based ethanol is independently selected from any value among 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 or a range value between any two of the above.
[0028] Optionally, the pressure of the reaction is 0.1 to 0.5 MPa, and the temperature of the reaction is 350 to 500 °C.
[0029] Optionally, the pressure of the reaction is independently selected from any value of 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa or a range value between any two of the above.
[0030] Optionally, the temperature of the reaction is independently selected from any value of 350 °C, 400 °C, 430 °C, 450 °C, 460 °C, 480 °C, 550 °C or a range value between any two of the above.
[0031] The beneficial effects that can be produced by this application include:
[0032] 1) The effect of removing impurities such as ester compounds, polymers, and pyridine bases in coal-based ethanol by the physical adsorption method in this application;
[0033] 2) In the process of dehydrogenating and aminating ethanol to produce acetonitrile, compared with the dehydrogenation and amination of purified coal-based ethanol and unpurified coal-based ethanol, the former shows higher ethanol conversion and higher acetonitrile selectivity on the same catalyst. Detailed implementation manners
[0034] The following describes this application in detail with reference to the examples, but this application is not limited to these examples.
[0035] Unless otherwise specified, the raw materials in the examples of this application are all purchased through commercial channels.
[0036] The analysis methods in the examples of this application are as follows:
[0037] Agilent 7890A gas chromatography is used to analyze the raw materials and products.
[0038] In the examples of this application, the catalyst activity evaluation indexes, namely ethanol conversion, ammonia conversion, and acetonitrile selectivity, are all calculated based on mass:
[0039] Ethanol conversion:
[0040]
[0041] Ammonia conversion:
[0042]
[0043] Acetonitrile selectivity:
[0044]
[0045] In the above formulas, m represents mass.
[0046] Comparative Example 1
[0047] According to the content of the active component tin, a certain amount of SnCl2·2H2O was weighed and dissolved in ethanol. The solution was added to the alumina support by the equal-volume impregnation method, stirred evenly, air-dried at room temperature, dried at 120 °C for 6 hours, and calcined at 700 °C for 3 hours. The content of tin in the prepared catalyst Cat-A was 20 wt%.
[0048] The dehydrogenative amination reaction performance of the Cat-A catalyst was evaluated using unpurified coal-based ethanol in a self-made small reaction device. The reactor had a diameter of 9 mm, and the loading amount of the Cat-A catalyst was 4 g. Under ammonia conditions, the temperature was raised to 430 °C at a heating rate of 10 °C / min, and ethanol was introduced. The evaluation duration was 50 h. The reaction conditions were: temperature 430 °C, pressure 0.1 MPa, mass space velocity of coal-based ethanol 0.5 h -1 , and the molar ratio of ammonia to coal-based ethanol was 6:1. The products were analyzed by Agilent 7890A GC. The specific evaluation results are shown in Table 1.
[0049] Comparative Example 2
[0050] 100 ml of 8-16 mesh activated carbon was loaded into a stainless steel reaction tube, and at 25 ℃ , 1.0 Mpa, WHSV: 1.0 h -1 Under these conditions, the coal-based ethanol was pumped into the stainless steel reaction tube (the raw material entered from the bottom and exited from the top) by a liquid pump to obtain purified coal-based ethanol for standby.
[0051] The dehydrogenative amination reaction performance of the Cat-A catalyst was evaluated using the purified coal-based ethanol in a self-made small reaction device. The reactor had a diameter of 9 mm, and the loading amount of the Cat-A catalyst was 4 g. Under ammonia conditions, the temperature was raised to 430 °C at a heating rate of 10 °C / min, and the purified coal-based ethanol was introduced. The evaluation duration was 50 h. The reaction conditions were: temperature 430 °C, pressure 0.1 MPa, mass space velocity of the purified coal-based ethanol 0.5 h -1 , and the molar ratio of ammonia to the purified coal-based ethanol was 6:1. The products were analyzed by Agilent 7890A GC. The specific evaluation results are shown in Table 1.
[0052] Comparative Example 3
[0053] 100 ml of 8-16 mesh 5A molecular sieve was loaded into a stainless steel reaction tube, and at 25 ℃ , 1.0 Mpa, WHSV: 1.0 h -1 , the coal-based ethanol was pumped into the stainless steel reaction tube (the raw material entered from the bottom and exited from the top) by a liquid pump to obtain purified coal-based ethanol for standby.
[0054] The dehydrogenation amination reaction performance of Cat-A catalyst to produce acetonitrile was evaluated using purified coal-based ethanol on a self-made small reaction device. The reactor had a diameter of 9 mm, and the loading amount of Cat-A catalyst was 4 g. Under ammonia gas conditions, the temperature was increased to 430 °C at a heating rate of 10 °C / min, and purified coal-based ethanol was introduced. The evaluation duration was 50 h. The reaction conditions were: temperature 430 °C, pressure 0.1 MPa, and the mass space velocity of purified coal-based ethanol was 0.5 h -1 , and the molar ratio of ammonia gas to purified coal-based ethanol was 6:1. The products were analyzed by Agilent 7890A GC. The specific evaluation results are shown in Table 1.
[0055] Example 1
[0056] Mix 50 ml of 8-16 mesh activated carbon and 50 ml of 5A molecular sieve evenly and load them into a stainless-steel reaction tube. At 25 °C, 1.0 Mpa, WHSV: 1.0 h -1 , pump coal-based ethanol into the stainless-steel reaction tube (the raw material enters from the bottom and exits from the top) by a liquid pump to obtain purified coal-based ethanol for standby.
[0057] The dehydrogenation amination reaction performance of Cat-A catalyst to produce acetonitrile was evaluated using purified coal-based ethanol on a self-made small reaction device. The reactor had a diameter of 9 mm, and the loading amount of Cat-A catalyst was 4 g. Under ammonia gas conditions, the temperature was increased to 430 °C at a heating rate of 10 °C / min, and purified coal-based ethanol was introduced. The evaluation duration was 50 h. The reaction conditions were: temperature 430 °C, pressure 0.1 MPa, and the mass space velocity of purified coal-based ethanol was 0.5 h -1 , and the molar ratio of ammonia gas to purified coal-based ethanol was 6:1. The products were analyzed by Agilent 7890A GC. The specific evaluation results are shown in Table 1.
[0058] Example 2
[0059] Mix 20 ml of 8-16 mesh activated carbon, 50 ml of 13X molecular sieve and 50 ml of clay evenly and load them into a stainless-steel tube. At 5 °C, 0.1 Mpa, WHSV: 0.2 h -1 , pump coal-based ethanol into the stainless-steel reaction tube (the raw material enters from the bottom and exits from the top) by a liquid pump to obtain purified coal-based ethanol for standby.
[0060] The dehydrogenation amination reaction performance of Cat-A catalyst was evaluated using purified coal-based ethanol on a self-made small-scale reaction device. The reactor had a diameter of 9 mm, and the loading amount of Cat-A catalyst was 4 g. The reaction conditions were as shown in Table 1. Under ammonia gas conditions, the temperature was raised to 500 °C at a heating rate of 10 °C / min, and purified coal-based ethanol was introduced. The evaluation duration was 50 h. The reaction conditions were: temperature 500 °C, pressure 0.1 MPa, mass space velocity of purified coal-based ethanol 0.1 h -1 , and the molar ratio of ammonia gas to purified coal-based ethanol was 2:1. The products were analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.
[0061] Example 3
[0062] 75 ml of 8-16 mesh acidic resin (D-005), 50 ml of silica gel, and 50 ml of 3A molecular sieve were mixed evenly and loaded into a stainless steel reaction tube. At 30 °C, 3.0 Mpa, WHSV: 0.5 h -1 , and coal-based ethanol was pumped into the stainless steel reaction tube (the raw material entered from the bottom and exited from the top) by a liquid pump to obtain purified coal-based ethanol for standby.
[0063] The dehydrogenation amination reaction performance of Cat-A catalyst was evaluated using purified coal-based ethanol on a self-made small-scale reaction device. The reactor had a diameter of 9 mm, and the loading amount of Cat-A catalyst was 4 g. The reaction conditions were as shown in Table 1. Under ammonia gas conditions, the temperature was raised to 450 °C at a heating rate of 10 °C / min, and purified coal-based ethanol was introduced. The evaluation duration was 50 h. The reaction conditions were: temperature 550 °C, pressure 0.3 MPa, mass space velocity of purified coal-based ethanol 0.3 h -1 , and the molar ratio of ammonia gas to purified coal-based ethanol was 4:1. The products were analyzed by Agilent 7890A GC, and the specific evaluation results are shown in Table 1.
[0064] Example 4
[0065] 60 ml of 20-40 mesh acidic resin (D-005), 40 ml of Y-type molecular sieve, and 40 ml of clay were mixed evenly and loaded into a stainless steel reactor. At 25 °C, 0.1 Mpa, WHSV: 0.4 h -1 , and coal-based ethanol was pumped into the stainless steel reaction tube (the raw material entered from the bottom and exited from the top) by a liquid pump to obtain purified coal-based ethanol for standby.
[0066] The dehydrogenation amination reaction performance of Cat-A catalyst was evaluated using purified coal-based ethanol on a self-made small-scale reaction device. The reactor had a diameter of 9 mm, and the loading amount of Cat-A catalyst was 4 g. The reaction conditions were as shown in Table 1. Under ammonia gas conditions, the temperature was raised to 400 °C at a heating rate of 10 °C / min, and then purified coal-based ethanol was introduced. The evaluation duration was 50 h. The reaction conditions were: temperature 450 °C, pressure 0.5 MPa, and the mass space velocity of purified coal-based ethanol 0.8 h -1 , and the molar ratio of ammonia gas to purified coal-based ethanol was 8:1. The products were analyzed using Agilent 7890AGC, and the specific evaluation results are shown in Table 1.
[0067] Example 5
[0068] According to the content of the active component tin, a certain amount of SnCl2·2H2O was weighed and dissolved in ethanol. This solution was added to the alumina support using the equal-volume impregnation method, stirred evenly, air-dried at room temperature, dried at 125 °C for 10 hours, and calcined at 750 °C for 3 hours to obtain a catalyst Cat-B with a tin content of 30 wt%.
[0069] 25 ml of 8-16 mesh acidic resin (D-005), 25 ml of activated carbon, 20 ml of BEA molecular sieve, and 30 ml of diatomite adsorbent were mixed evenly and loaded into a stainless-steel reactor. At 25 °C, 0.1 Mpa, and WHSV: 0.3 h -1 , and the coal-based ethanol was pumped into the stainless-steel reaction tube (the raw material entered from the bottom and exited from the top) by a liquid pump to obtain purified coal-based ethanol for standby.
[0070] The dehydrogenation amination reaction performance of catalyst Cat-B was evaluated using purified coal-based ethanol on a self-made small-scale reaction device. The reactor had a diameter of 9 mm, and the loading amount of Cat-B catalyst was 4 g. Under ammonia gas conditions, the temperature was raised to 430 °C at a heating rate of 10 °C / min, and then purified coal-based ethanol was introduced. The evaluation duration was 50 h. The reaction conditions were: temperature 430 °C, pressure 0.1 MPa, and the mass space velocity of purified coal-based ethanol 0.5 h -1 , and the molar ratio of ammonia gas to purified coal-based ethanol was 6:1. The products were analyzed using Agilent 7890A GC, and the specific evaluation results are shown in Table 1.
[0071] Table 1 Catalyst reaction performance
[0072]
[0073] The experimental results in Table 1 show that, compared with the dehydrogenation amination of unpurified coal-based ethanol to acetonitrile (Comparative Example 1), both the ethanol conversion rate and acetonitrile selectivity were significantly improved during the dehydrogenation amination of purified coal-based ethanol to acetonitrile, as in Example 1.
[0074] The dehydrogenamination of coal-based ethanol adsorbed and purified by single solid adsorbent A (Comparative Example 2) or solid adsorbent B (Comparative Example 3) has a certain degree of improvement compared with that of the unpurified one (Comparative Example 1), but it is not as excellent as the reaction performance of the dehydrogenamination of coal-based ethanol purified after mixing A / B, such as in Examples 1 to 5.
[0075] As mentioned above, only several embodiments of the present application are described, and it does 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 above is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.
Claims
1. A purification method for coal-based ethanol, characterized in that the purification method includes: bringing the coal-based ethanol I containing impurities into contact with a solid adsorbent for adsorption to obtain purified coal-based ethanol II; the solid adsorbent is composed of solid adsorbent A and solid adsorbent B; the solid adsorbent A is activated carbon and / or resin; the solid adsorbent B is selected from at least one of molecular sieve, silica gel, clay, and diatomaceous earth.
2. The purification method according to claim 1, characterized in that the impurities include ester compounds, polymers, and pyridine bases; in the coal-based ethanol II, the total concentration of ester compounds, polymers, and pyridine bases < 50 ppm.
3. The purification method according to claim 1, characterized in that in the solid adsorbent, the volume ratio of solid adsorbent A to solid adsorbent B is 0.2 - 1:
1.
4. The purification method according to claim 1, characterized in that in the solid adsorbent, the volume ratio of solid adsorbent A to solid adsorbent B is 0.3 - 0.
9.
5. The purification method according to claim 1, characterized in that The adsorption conditions are as follows: the adsorption temperature is 5 - 30 °C; the adsorption pressure is 0.1 - 3.0 Mpa; the mass space velocity of coal-based ethanol I is 0.2 - 1 h -1 .
6. The purification method according to claim 1, characterized in that The adsorption conditions are as follows: the adsorption temperature is 10 - 25°C; the adsorption pressure is 0.3 - 2.8 Mpa; the mass space velocity of coal-based ethanol I is 0.4 - 0.8 h -1 .
7. A method for promoting the dehydrogenation amination of coal-based ethanol to acetonitrile, characterized in that the method includes: bringing a raw material containing coal-based ethanol and ammonia into contact with a catalyst for reaction to obtain a product containing acetonitrile; the coal-based ethanol is the purified coal-based ethanol II obtained by the purification method according to any one of claims 1 - 6.
8. The method according to claim 7, characterized in that the molar ratio of ammonia to coal-based ethanol is 2 - 8.
9. The method according to claim 7, characterized in that The mass hourly space velocity of the coal-based ethanol is 0.1 to 1.0 h -1 .
10. The method according to claim 7, characterized in that the pressure of the reaction is 0.1 - 0.5 MPa, and the temperature of the reaction is 350 - 500 °C.