New method for removing acrylonitrile and purifying acetonitrile by using resin column

Abstract

The invention discloses a novel method for removing acrylonitrile and purifying acetonitrile by using a resin column, and belongs to the technical field of chemical engineering. The method comprises the following steps: heating an acetonitrile crude product, an acidic resin column and an alkaline resin column, then controlling the continuous feeding of the acetonitrile crude product, and enabling the acetonitrile crude product to pass through a three-stage acidic resin column and then pass through a three-stage alkaline resin column to obtain purified acetonitrile. According to the method, acrylonitrile can be completely removed, and the acetonitrile purification effect is good; compared with a traditional chemical method, the method is more efficient, simpler, more convenient, green, safer and free of waste residues; the method can be used for treating a large amount of raw material acetonitrile, the treatment speed is high, and the regeneration cost is low.

Description

Technical Field

[0001] The invention specifically relates to a new method for removing acrylonitrile from a resin column and purifying acetonitrile, and belongs to the field of chemical production. Background Art

[0002] Acetonitrile, also known as methyl nitrile and methyl cyanide, is the single most saturated aliphatic nitrile. It exists as a colorless transparent liquid with a molecular weight of 41.052, a CAS number of 75-05-8, a melting point of -45°C, a boiling point of 81-82°C, and a density of 0.786 g / cm 3 , the flash point is 12.8℃ (CC). Because acetonitrile has a unique functional group cyano, it has excellent solvent properties. It is infinitely miscible with water and alcohol, can dissolve a variety of organic, inorganic and gaseous substances, and has a better distribution ratio and desorption ability, and can dissolve some inorganic salts. Because the carbon-nitrogen triple bond of acetonitrile is prone to typical nitrile reactions, acetonitrile can not only be used as a solvent, but also can be used to produce many nitrogen-containing compounds. It is an important organic intermediate. At present, pure acetonitrile is mostly used as a chromatographic analysis standard substance, a solvent for high-pressure liquid chromatography (HPLC), a gas chromatography stationary liquid, and as a solvent for most inorganic compounds, spectrophotometric determination and non-aqueous titration solvent.

[0003] At present, there are two main processes for removing acrylonitrile from acetonitrile solution: chemical removal of acrylonitrile and resin column removal of acrylonitrile.

[0004] In the chemical method for removing acrylonitrile, CN104529821A provides a method for removing acrylonitrile from an acetonitrile product, using acetonitrile with an organic component content of 97.5% to 99% as a raw material, preparing a strong oxidant solution with a mass concentration of 0.5% to 6% at room temperature, according to the molar ratio of acrylonitrile to strong oxidant = 1:1 to 1:2, weighing a certain amount of the strong oxidant solution into acetonitrile, starting stirring and heating, turning on the cooling water of the reflux pipe, when the strong oxidant is a stable strong oxidant, when the temperature reaches 74 to 80°C, controlling the heating to keep the solution reflux for 5 to 20 minutes, and obtaining the purified acetonitrile product; when the strong oxidant is a weakly stable strong oxidant, when the temperature reaches 30 to 40°C, controlling the heating to keep the solution reflux for 30 to 50 minutes, and obtaining the purified acetonitrile product. This method does not affect the acetonitrile content of the product, the removal rate of acrylonitrile reaches 100%, and the product yield is greater than 99%. However, this chemical method for removing acrylonitrile uses traditional potassium permanganate oxidants, and there are problems such as impurities produced by the reaction are difficult to dissolve in water, need to be filtered to remove impurities, and the operation is cumbersome. In addition, the chemical method for removing acrylonitrile is also dangerous in industrial production: potassium permanganate dust or smoke can cause respiratory irritation and damage after inhalation, which is potentially harmful to operators.

[0005] Resin column removes acrylonitrile mainly by passing the acetonitrile solution through a chromatography column filled with resin, and the resin removes trace acrylonitrile in the acetonitrile solution through ion exchange / adsorption / reaction and other methods. CN101171233B provides a high-purity acetonitrile and a method for manufacturing the same, and the process mentions that the purified acetonitrile obtained is passed through a strongly acidic cation exchange resin to obtain high-purity acetonitrile. However, from the results, the effect of using resin alone to remove acrylonitrile is poor, and there are problems such as the flow rate of acetonitrile cannot be too fast, the processing volume is small, the regeneration cost is large, and the acrylonitrile cannot be completely removed in the end. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a new method for removing acrylonitrile and purifying acetonitrile by using a resin column. The present invention uses high-concentration acetonitrile (acetonitrile content is 98.0-99.0% (v / v), acrylonitrile content is 10-20ppm) as raw material, and firstly passes the raw material through an acidic resin adsorption column to convert a trace amount of acrylonitrile in the acetonitrile solution into acrylic acid; and then passes through an alkaline resin adsorption column to adsorb acrylic acid impurities in the acetonitrile solution, thereby removing acrylonitrile.

[0007] In the acetonitrile solution finally obtained by the present invention, the removal rate of acrylonitrile reaches 100%, and the product yield is greater than 99%, indicating that the present invention can completely remove acrylonitrile and has a good effect in purifying acetonitrile. The present invention also avoids the problems of chemical acrylonitrile removal, such as the reaction-generated impurities are insoluble in water, the impurities need to be filtered to remove, the operation is cumbersome, and there is a certain risk in industrial production. At the same time, the present invention can process a large amount of raw materials, has a fast processing speed, and has a low regeneration cost, and solves the problems of the resin column acrylonitrile removal method in the prior art, such as the small processing capacity of acetonitrile, the large regeneration cost, and the inability to completely remove acrylonitrile.

[0008] In view of the above technical problems, the technical solution of the present invention is as follows:

[0009] The present invention provides a novel method for removing acrylonitrile from a resin column to purify acetonitrile, the method comprising:

[0010] (1) Preheating: Heat the crude acetonitrile, the acidic resin column, and the basic resin column separately;

[0011] (2) Purification: The crude acetonitrile is passed through an acidic resin column and a basic resin column to obtain purified acetonitrile.

[0012] In one embodiment of the present invention, the acetonitrile content in the crude acetonitrile is 98.0-99.0% (v / v), and the acrylonitrile content is 10-20 ppm.

[0013] In one embodiment of the present invention, the acetonitrile content in the crude acetonitrile is 98.0-99.0% (v / v), and the acrylonitrile content is 14 ppm.

[0014] In one embodiment of the present invention, the heating temperature is 50-70°C; preferably, the heating temperature is 60°C.

[0015] In one embodiment of the present invention, the feed rate of the crude acetonitrile through the acidic resin column or the basic resin column is 0.1-5 BV / h; preferably, the feed rate is 0.5-3 BV / h; more preferably, the feed rate is 2 BV / h.

[0016] In one embodiment of the present invention, the filler of the acidic resin column is 001x7 gel strong acid cation exchange resin.

[0017] In one embodiment of the present invention, the preparation method of the acidic resin column is: washing the acidic resin in water, letting it stand, pouring it into a chromatography column for filling, draining the water, and obtaining the acidic resin column.

[0018] In one embodiment of the present invention, the outer diameter:height of the acidic resin column is (10:500) to (50:500); preferably, the outer diameter:height of the acidic resin column is 15:500.

[0019] In one embodiment of the present invention, the acidic resin is 001x7 gel strong acid cation exchange resin.

[0020] In one embodiment of the present invention, the standing time is 0.2 to 1 h.

[0021] In one embodiment of the present invention, the chromatography column is a glass chromatography column, a gel chromatography column or a pressurized chromatography column.

[0022] In one embodiment of the present invention, the filling volume of the acidic resin column is 300-700 mL; preferably, the filling volume is 500 mL.

[0023] In one embodiment of the present invention, the loading amount of the acidic resin is 250-400 g.

[0024] In one embodiment of the present invention, the acidic resin column is passed through an HCl solution before use.

[0025] In one embodiment of the present invention, the concentration of the HCl solution is 2% to 8% (v / v).

[0026] In one embodiment of the present invention, the throughput of the HCl solution is 2 to 3 times the volume of the resin packed in the chromatography column; preferably, the throughput is 2 times the volume of the resin packed in the resin column.

[0027] In one embodiment of the present invention, the acidic resin column is: 001x7 gel strong acid cation exchange resin is put into water for cleaning, allowed to stand for 0.5h, and then poured into a glass chromatography column with a filling amount of 500mL, so that its outer diameter: height = 15:500, and deionized water is drained; 5% (v / v) HCl solution is used to pass through the acidic resin column filled with 001x7 gel strong acid cation exchange resin (the amount of HCl solution passed is twice the volume of the filled resin) to obtain an acidic resin column.

[0028] In one embodiment of the present invention, the filler of the alkaline resin column is LX-6703 food grade macroporous acrylic acid weak base anion exchange resin.

[0029] In one embodiment of the present invention, the preparation method of the basic resin column is: wash the basic resin in water, let it stand, pour it into a chromatography column for filling, drain the water, and obtain the basic resin column.

[0030] In one embodiment of the present invention, the outer diameter:height of the alkaline resin column is (10:500) to (50:500); preferably, the outer diameter:height of the alkaline resin column is 15:500.

[0031] In one embodiment of the present invention, the alkaline resin is LX-6703 food grade macroporous acrylic acid weak base anion exchange resin.

[0032] In one embodiment of the present invention, the standing time is 0.2 to 1 h.

[0033] In one embodiment of the present invention, the chromatography column is a glass chromatography column, a gel chromatography column or a pressurized chromatography column.

[0034] In one embodiment of the present invention, the filling volume of the basic resin column is 300-700 mL; preferably, the filling volume is 500 mL.

[0035] In one embodiment of the present invention, the loading amount of the basic resin is 300 to 450 g.

[0036] In one embodiment of the present invention, the basic resin column is passed through a NaOH solution before use.

[0037] In one embodiment of the present invention, the concentration of the NaOH solution is 2% to 8% (w / v, g / 100 mL).

[0038] In one embodiment of the present invention, the throughput of the NaOH solution is 2 to 3 times the volume of the chromatography column packed resin; preferably, the throughput is 2 times the volume of the chromatography column packed resin.

[0039] In one embodiment of the present invention, the alkaline resin column is: LX-6703 food grade macroporous acrylic acid weak base anion exchange resin is put into water for cleaning, allowed to stand for 0.5h, and then poured into a glass chromatography column with a filling amount of 500mL, so that its outer diameter: height = 15m:500m, and deionized water is drained; a 5% (w / v, g / 100mL) NaOH solution is used to pass through the alkaline resin column filled with LX-6703 food grade macroporous acrylic acid weak base anion exchange resin (the amount of NaOH solution passed is twice the volume of the filled resin) to obtain a basic resin column.

[0040] In one embodiment of the present invention, the method is:

[0041] (1) Preheating: Heat the crude acetonitrile, the acidic resin column, and the basic resin column to 50-70°C respectively;

[0042] (2) Purification: The crude acetonitrile is passed through a first-stage acidic resin column, a second-stage acidic resin column, a third-stage acidic resin column and a first-stage basic resin column, a second-stage basic resin column, and a third-stage basic resin column in sequence at a feed rate of 0.1 to 5 BV / h to obtain purified acetonitrile.

[0043] In one embodiment of the present invention, the concentration of the crude acetonitrile is 98% to 99% (v / v).

[0044] In one embodiment of the present invention, the heating temperature is 60°C.

[0045] In one embodiment of the present invention, the feed rate of the crude acetonitrile through the acidic resin column or the basic resin column is 0.5 to 3 BV / h; preferably, the feed rate is 2 BV / h.

[0046] In one embodiment of the present invention, the filler of the acidic resin column is 001x7 gel strong acid cation exchange resin.

[0047] In one embodiment of the present invention, the preparation method of the first-level acid resin column, the second-level acid resin column, and the third-level acid resin column is: the acid resin is washed in water, allowed to stand, poured into a chromatography column for filling, and the water is drained to obtain a first-level acid resin column, and the second-level acid resin column and the third-level acid resin column are obtained in the same way.

[0048] In one embodiment of the present invention, the outer diameter:height of the acidic resin column is (10:500) to (50:500); preferably, the outer diameter:height of the acidic resin column is 15:500.

[0049] In one embodiment of the present invention, the acidic resin is 001x7 gel strong acid cation exchange resin.

[0050] In one embodiment of the present invention, the standing time is 0.2 to 1 h.

[0051] In one embodiment of the present invention, the chromatography column is a glass chromatography column, a gel chromatography column or a pressurized chromatography column.

[0052] In one embodiment of the present invention, the loading amount of the acidic resin is 300-700 mL; preferably, the loading amount is 500 mL.

[0053] In one embodiment of the present invention, the loading amount of the acidic resin is 250-400 g.

[0054] In one embodiment of the present invention, the acidic resin column is passed through an HCl solution before use.

[0055] In one embodiment of the present invention, the concentration of the HCl solution is 2% to 8% (v / v).

[0056] In one embodiment of the present invention, the throughput of the HCl solution is 2 to 3 times the volume of the chromatography column packed resin; preferably, the throughput is 2 times the volume of the chromatography column packed resin.

[0057] In one embodiment of the present invention, the filler of the alkaline resin column is LX-6703 food grade macroporous acrylic acid weak base anion exchange resin.

[0058] In one embodiment of the present invention, the preparation method of the basic resin column is: wash the basic resin in water, let it stand, pour it into a chromatography column for filling, drain the water, and obtain a first-level basic resin column. The second-level basic resin column and the third-level basic resin column are obtained by the same method.

[0059] In one embodiment of the present invention, the outer diameter:height of the alkaline resin column is (10:500) to (50:500); preferably, the outer diameter:height of the alkaline resin column is 15:500.

[0060] In one embodiment of the present invention, the alkaline resin is LX-6703 food grade macroporous acrylic acid weak base anion exchange resin.

[0061] In one embodiment of the present invention, the standing time is 0.2 to 1 h.

[0062] In one embodiment of the present invention, the chromatography column is a glass chromatography column, a gel chromatography column or a pressurized chromatography column.

[0063] In one embodiment of the present invention, the filling volume of the basic resin column is 300-700 mL; preferably, the filling volume is 500 mL.

[0064] In one embodiment of the present invention, the filling amount of the basic resin column is 300-450 g.

[0065] In one embodiment of the present invention, the basic resin column is passed through a NaOH solution before use.

[0066] In one embodiment of the present invention, the concentration of the NaOH solution is 2% to 8% (w / v, g / 100 mL).

[0067] In one embodiment of the present invention, the throughput of the NaOH solution is 2 to 3 times the volume of the chromatography column packed resin; preferably, the throughput is 2 times the volume of the chromatography column packed resin.

[0068] The present invention also provides high-purity acetonitrile, which is prepared by the above-mentioned preparation method.

[0069] In one embodiment of the present invention, acrylonitrile and acrylic acid are not detected in the high-purity acetonitrile, the removal rate of acrylonitrile is 100%, and the acetonitrile yield reaches 99.9%.

[0070] Beneficial Effects

[0071] (1) The method of the present invention has a 100% removal rate for acrylonitrile, and a product acetonitrile yield of greater than 99%. The acrylonitrile can be completely removed, and the effect of purifying acetonitrile is very good.

[0072] (2) Chemical methods for removing acrylonitrile also have certain risks in industrial production: inhalation of potassium permanganate dust or smoke can cause respiratory irritation and damage, which is potentially harmful to operators. Compared with the traditional method of removing acrylonitrile using potassium permanganate oxidants, the method of the present invention is more efficient, simple, green and safe, and does not produce waste residue. It avoids the problems of impurities produced by the reaction being difficult to dissolve in water, requiring filtration to remove impurities, complicated operations, and certain risks in industrial production.

[0073] (3) The method of the present invention can process a large amount of raw material acetonitrile, with a fast processing speed and low regeneration cost.

[0074] (4) The resin column in the method of the present invention is regenerable, environmentally friendly and cost-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 The present invention is a process flow chart of removing acrylonitrile and purifying acetonitrile by using a resin column. DETAILED DESCRIPTION

[0076] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0077] The methods involved in the following embodiments are:

[0078] 1. Use gas chromatography to analyze and identify acrylonitrile, acrylic acid and acetonitrile;

[0079] 2. The calculation method of acetonitrile yield is:

[0080] Acetonitrile yield = mass of acetonitrile after treatment / mass of acetonitrile in concentrated acetonitrile before treatment × 100%;

[0081] 3. Resin regeneration method:

[0082] The purpose of setting the same three-stage acidic resin column and the same three-stage alkaline resin column in the present invention is to achieve continuous feeding, that is, the raw material acetonitrile can be processed in large quantities and quickly. The processing speed of the resin column of the present invention can reach 2BV / h. The resin column reaches saturation after being used for 60 hours. When the resin in the first-stage resin column needs to be regenerated, it can be regenerated separately. After the regeneration is completed, it is connected to the third-stage resin column. By analogy, the regeneration method of the second and third-stage resin columns is the same.

[0083] (1) Acidic resin column regeneration method: Use saturated brine to pass through the resin column to remove soluble impurities in the resin, and then rinse it with clean water; pass 5BV of 5% (v / v) HCl solution through the resin column at a rate of 2BV / h, and rinse it with deionized water until it is neutral.

[0084] (2) Alkaline resin column regeneration method: Use saturated salt water to pass through the resin column to remove soluble impurities in the resin, and then rinse it with clean water; then pass 5BV of 5% (w / v, g / 100mL) NaOH solution through the resin column at a rate of 2BV / h, and rinse it with deionized water until it is neutral.

[0085] The raw materials involved in the following embodiments are:

[0086] The 001x7 gel strong acid cation exchange resin, LX-6703 food grade macroporous acrylic acid weak base anion exchange resin, and LSC-930 acid-based resin chelating resin involved in the present invention were purchased from Xi'an Lanxiao Technology Co., Ltd.;

[0087] The crude acetonitrile product described below is concentrated acetonitrile (produced by Nantong Liyang Chemical Co., Ltd.), which is produced by reacting raw acetic acid with ammonia in the presence of a catalyst; the acetonitrile content in the crude acetonitrile product is 98.0-99.0% (v / v), and the acrylonitrile content is 14ppm.

[0088] Example 1: A method for removing acrylonitrile from a resin column to purify acetonitrile

[0089] The specific steps are as follows:

[0090] 1. Preparation of acid and alkaline resin columns:

[0091] The acid resin (001x7 gel strong acid cation exchange resin) was washed in deionized water, allowed to stand for 0.5 h, and then poured into a glass chromatography column. The filling amount of the glass chromatography column was 500 mL, and the filling amount of the acid resin was 310 g, so that the outer diameter: height = 15:500, and the deionized water was drained to obtain a first-level acid resin column. The second-level acid resin column and the third-level acid resin column were obtained by the same treatment;

[0092] The alkaline resin (LX-6703 food-grade macroporous acrylic weak-base anion exchange resin) was washed in deionized water, allowed to stand for 0.5 h, and then poured into a glass chromatography column, the filling amount of the glass chromatography column was 500 mL, the filling amount of the alkaline resin was 393 g, and the outer diameter: height was 15:500, and the deionized water was drained to obtain a first-level alkaline resin column, a second-level alkaline resin column, and a third-level alkaline resin column;

[0093] Before using the resin column, a 5% (v / v) HCl solution is passed through an acidic resin column filled with 001x7 gel strong acid cation exchange resin (the amount of HCl solution passed is twice the volume of the loaded resin), and a 5% (w / v, g / 100 mL) NaOH solution is passed through a resin column filled with LXC-6703 (the amount of NaOH solution passed is twice the volume of the loaded resin), the purpose of which is to activate the resin and increase the resin adsorption capacity; finally, a first-level acidic resin column, a second-level acidic resin column, a third-level acidic resin column and a first-level basic resin column, a second-level basic resin column, and a third-level basic resin column treated with HCl or NaOH are obtained;

[0094] 2. Remove acrylonitrile and purify acetonitrile:

[0095] (1) Preheating: heating the crude acetonitrile and the acidic and basic resin columns treated with HCl or NaOH prepared in step (1) to 60° C. respectively;

[0096] (2) Purification: The crude acetonitrile is adjusted to be continuously fed at a rate of 2 BV / h, first passing through 1, 2, and 3 acidic resin columns in sequence, and then the crude acetonitrile after passing through the acidic resin columns is passed through 1, 2, and 3 basic resin columns in sequence to obtain purified acetonitrile.

[0097] The specific process is as follows Figure 1 shown.

[0098] The results are as follows:

[0099] No acrylonitrile was detected in the crude acetonitrile after passing through the 3-stage acidic resin column, which means that acrylonitrile was completely converted into acrylic acid at this time; no acrylonitrile and acrylic acid were detected in the crude acetonitrile after passing through the 3-stage basic resin column, indicating that the removal rate of acrylonitrile was 100% and the acetonitrile yield reached 99.9%.

[0100] Example 2: A method for removing acrylonitrile from a resin column to purify acetonitrile

[0101] The specific implementation is the same as in Example 1, except that step 2(2) is adjusted to:

[0102] (2) Purification: The crude acetonitrile is adjusted to be continuously fed at a rate of 0.5 BV / h, first passing through 1, 2, and 3 acidic resin columns in sequence, and then the crude acetonitrile after passing through the acidic resin columns is passed through 1, 2, and 3 basic resin columns in sequence to obtain purified acetonitrile.

[0103] The remaining steps are the same as in Example 1, and the results are as follows:

[0104] No acrylonitrile was detected in the crude acetonitrile after passing through the 3-stage acidic resin column, which means that acrylonitrile was completely converted into acrylic acid at this time; no acrylonitrile and acrylic acid were detected in the crude acetonitrile after passing through the 3-stage basic resin column, and the final acrylonitrile removal rate was 100%, and the acetonitrile yield was 99.9%.

[0105] Example 3: A method for removing acrylonitrile from a resin column to purify acetonitrile

[0106] The specific implementation is the same as in Example 1, except that step 2(1) is adjusted to:

[0107] (1) Preheating: heating the crude acetonitrile and the acidic and basic resin columns treated with HCl or NaOH prepared in step (1) to 40° C. respectively;

[0108] The remaining steps are the same as in Example 1, and the results are as follows:

[0109] The acrylonitrile content detected in the crude acetonitrile after passing through the 3-stage acidic resin column was 9 ppm, which means that the acrylonitrile was partially converted into acrylic acid at this time; the acrylonitrile content detected in the crude acetonitrile after passing through the 3-stage basic resin column was 4 ppm, and no acrylic acid was detected. The final acrylonitrile removal rate was 71.4%, and the acetonitrile yield was 99.3%.

[0110] Example 4: A method for removing acrylonitrile from a resin column to purify acetonitrile

[0111] The specific implementation is the same as in Example 1, except that step 2(1) is adjusted to:

[0112] (1) Preheating: heating the crude acetonitrile and the acidic and basic resin columns treated with HCl or NaOH prepared in step (1) to 70° C. respectively;

[0113] The remaining steps are the same as in Example 1, and the results are as follows:

[0114] No acrylonitrile was detected in the crude acetonitrile after passing through the 3-stage acidic resin column, which means that acrylonitrile was completely converted into acrylic acid at this time; no acrylonitrile and acrylic acid were detected in the crude acetonitrile after passing through the 3-stage basic resin column, and the final acrylonitrile removal rate was 100%, and the acetonitrile yield was 95.0%.

[0115] Example 5: A method for removing acrylonitrile from a resin column to purify acetonitrile

[0116] The specific implementation is the same as in Example 1, except that step 2(2) is adjusted to:

[0117] (2) Purification: The crude acetonitrile is adjusted to continuously feed at a rate of 5 BV / h, first passing through 1, 2, and 3 acidic resin columns in sequence, and then the crude acetonitrile after passing through the acidic resin columns is passed through 1, 2, and 3 basic resin columns in sequence to obtain purified acetonitrile.

[0118] The remaining steps are the same as in Example 1, and the results are as follows:

[0119] No acrylonitrile was detected in the crude acetonitrile after passing through the 3-stage acidic resin column, which means that acrylonitrile was completely converted into acrylic acid at this time; no acrylonitrile and acrylic acid were detected in the crude acetonitrile after passing through the 3-stage basic resin column, and the final acrylonitrile removal rate was 82.1%, and the acetonitrile yield was 99.3%.

[0120] Example 6: A method for removing acrylonitrile from a resin column to purify acetonitrile

[0121] The specific implementation is the same as in Example 1, except that step 2(1) is adjusted to:

[0122] (1) Preheating: heating the crude acetonitrile and the acidic and alkaline resin columns treated with HCl or NaOH prepared in step (1) to 75° C. respectively;

[0123] The remaining steps are the same as in Example 1, and the results are as follows:

[0124] No acrylonitrile was detected in the crude acetonitrile after passing through the 3-stage acidic resin column, which means that acrylonitrile was completely converted into acrylic acid at this time; no acrylonitrile and acrylic acid were detected in the crude acetonitrile after passing through the 3-stage basic resin column, and the final acrylonitrile removal rate was 100%, and the acetonitrile yield was 89.0%.

[0125] Example 7: A method for removing acrylonitrile from a resin column to purify acetonitrile

[0126] The specific implementation is the same as in Example 1, except that step 1 is adjusted to:

[0127] 1. Preparation of acid and alkaline resin columns:

[0128] The acid resin (001x7 gel strong acid cation exchange resin) was washed in deionized water, allowed to stand for 0.5 h, and then poured into a glass chromatography column. The filling amount of the glass chromatography column was 500 mL, and the filling amount of the acid resin was 310 g, so that the outer diameter: height = 50:500, and the deionized water was drained to obtain a first-level acid resin column. The second-level acid resin column and the third-level acid resin column were obtained by the same treatment;

[0129] The alkaline resin (LX-6703 food-grade macroporous acrylic weak-base anion exchange resin) was washed in deionized water, allowed to stand for 0.5 h, and then poured into a glass chromatography column. The filling amount of the glass chromatography column was 500 mL, and the filling amount of the alkaline resin was 393 g, so that its outer diameter: height = 50:500, and the deionized water was drained to obtain a first-level alkaline resin column, a second-level alkaline resin column, and a third-level alkaline resin column;

[0130] Before using the resin column, a 5% (v / v) HCl solution is passed through an acidic resin column filled with 001x7 gel strong acid cation exchange resin (the amount of HCl solution passed is twice the volume of the loaded resin), and a 5% (w / v, g / 100 mL) NaOH solution is passed through a resin column filled with LXC-6703 (the amount of NaOH solution passed is twice the volume of the loaded resin); finally, a first-level acidic resin column, a second-level acidic resin column, a third-level acidic resin column and a first-level basic resin column, a second-level basic resin column, and a third-level basic resin column treated with HCl or NaOH are obtained;

[0131] The remaining steps are the same as in Example 1, and the results are as follows:

[0132] No acrylonitrile was detected in the crude acetonitrile after passing through the 3-stage acidic resin column, which means that acrylonitrile was completely converted into acrylic acid at this time; no acrylonitrile and acrylic acid were detected in the crude acetonitrile after passing through the 3-stage basic resin column, and the final acrylonitrile removal rate was 97.8%, and the acetonitrile yield was 99.7%.

[0133] Comparative Example 1: A method for removing acrylonitrile and purifying acetonitrile by using a resin column

[0134] The specific implementation method is the same as Example 1, except that the heating temperature of the crude acetonitrile and the acid and alkaline resin columns is not regulated, and the columns are directly passed at room temperature 25° C., that is, step 2 is adjusted to:

[0135] 2. Remove acrylonitrile and purify acetonitrile:

[0136] At room temperature of 25°C, the crude acetonitrile was adjusted to be continuously fed at a rate of 2BV / h, and first passed through the 1st, 2nd, and 3rd acidic resin columns in sequence, and then the crude acetonitrile after passing through the acidic resin columns was passed through the 1st, 2nd, and 3rd basic resin columns in sequence to obtain purified acetonitrile. The remaining steps were the same as in Example 1, and the results were as follows:

[0137] The acrylonitrile content detected in the crude acetonitrile after passing through the 3-stage acidic resin column was 14ppm, which means that acrylonitrile was not converted into acrylic acid at this time; the acrylonitrile content detected in the crude acetonitrile after passing through the 3-stage basic resin column was 8.3ppm, and no acrylic acid was detected. The final acrylonitrile removal rate was 40.7%, and the acetonitrile yield was 99.1%.

[0138] Comparative Example 2: A method for removing acrylonitrile and purifying acetonitrile by using a resin column

[0139] The specific implementation is the same as in Example 1, except that step 2(2) is adjusted to:

[0140] (2) Purification: The crude acetonitrile is adjusted to continuously feed at a rate of 8 BV / h, first passing through 1, 2, and 3 acidic resin columns in sequence, and then the crude acetonitrile after passing through the acidic resin columns is passed through 1, 2, and 3 basic resin columns in sequence to obtain purified acetonitrile.

[0141] The remaining steps are the same as in Example 1, and the results are as follows:

[0142] No acrylonitrile was detected in the crude acetonitrile after passing through the 3-stage acidic resin column, which means that acrylonitrile was completely converted into acrylic acid at this time; no acrylonitrile and acrylic acid were detected in the crude acetonitrile after passing through the 3-stage basic resin column, and the final acrylonitrile removal rate was 57.9%, and the acetonitrile yield was 99.0%.

[0143] Comparative Example 3: A method for removing acrylonitrile and purifying acetonitrile by using a resin column

[0144] 1. On the basis of Example 1, the 001x7 gel strong acid cation exchange resin is replaced by other acidic resins, such as LSC-930 acid-removing resin chelating resin, or the basic resin is replaced by other basic resins, and the other conditions are the same as in Example 1.

[0145] The results showed that acrylonitrile was only partially converted into acrylic acid, and the speed was slow and the efficiency was low.

[0146] 2. Based on Example 1, step 2(2) was adjusted to pass the crude acetonitrile through the first and second acidic resin columns, and then through the first and second basic resin columns. The remaining conditions were the same as those in Example 1.

[0147] The results showed that: there were problems such as only part of acrylonitrile was converted into acrylic acid and incomplete removal of acrylonitrile;

[0148] 3. Based on Example 1, step 2(2) was adjusted to pass the crude acetonitrile through 1, 2, 3, and 4 acidic resin columns in sequence, and then through 1, 2, 3, and 4 basic resin columns in sequence.

[0149] The results showed that: the results were not further optimized, and 4-stage resin columns would increase the complexity of the operation, so it was not necessary to set up 4 or more stages of resin columns.

[0150] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for removing acrylonitrile from a resin column to purify acetonitrile, characterized in that: The method is: (1) Preheating: Heat the crude acetonitrile, the acidic resin column, and the basic resin column to 50-70°C respectively; (2) Purification: The crude acetonitrile is passed through an acidic resin column and a basic resin column in sequence at a feed rate of 0.1 to 5 BV / h to obtain purified acetonitrile; The acetonitrile content in the crude acetonitrile product is 98.0-99.0% v / v, and the acrylonitrile content is 10-20 ppm; The filler of the acidic resin column is 001x7 gel strong acid cation exchange resin; The filler of the alkaline resin column is LX-6703 food-grade macroporous acrylic acid weak-base anion exchange resin.

2. The method according to claim 1, characterized in that The heating temperature is 60°C.

3. The method according to claim 1 or 2, characterized in that: The feed rate is 0.5-3 BV / h; preferably, the feed rate is 2 BV / h.

4. The method according to any one of claims 1 to 3, characterized in that: The preparation method of the acidic resin column is as follows: 001x7 gel strong acid cation exchange resin is put into water for washing, poured into a chromatography column for filling, and the water is drained to obtain an acidic resin column; and, before use, HCl solution is passed through the acidic resin column; The preparation method of the alkaline resin column is as follows: LX-6703 food-grade macroporous acrylic acid weak-base anion exchange resin is put into water for cleaning, poured into a chromatography column for filling, and the water is drained to obtain an alkaline resin column, and NaOH solution is passed through the alkaline resin column before use.

5. The method according to any one of claims 1 to 4, characterized in that: The acetonitrile content in the crude acetonitrile product is 98.0-99.0% (v / v), and the acrylonitrile content is 14 ppm.

6. The method according to any one of claims 1 to 5, characterized in that: The outer diameter:height of the acidic resin column or the alkaline resin column is (10:500) to (50:500); the filling volume of the acidic resin column or the alkaline resin column is 300 to 700 mL.

7. The method according to claim 4 or 6, characterized in that: The chromatography column is a glass chromatography column, a gel chromatography column or a pressurized chromatography column.

8. The method according to claim 1, characterized in that The method is: (1) Preheating: Heat the crude acetonitrile, the acidic resin column, and the basic resin column to 50-70°C respectively; (2) Purification: The crude acetonitrile is passed through a first-stage acidic resin column, a second-stage acidic resin column, a third-stage acidic resin column, a first-stage basic resin column, a second-stage basic resin column, and a third-stage basic resin column in sequence at a feed rate of 0.1 to 5 BV / h to obtain purified acetonitrile; The preparation method of the first-level acid resin column, the second-level acid resin column, and the third-level acid resin column is as follows: wash the acid resin in water, pour it into a resin column for filling, drain the water, and obtain the first-level acid resin column; obtain the second-level acid resin column and the third-level acid resin column in the same way; and pass the first, second, and third-level acid resin columns with HCl solution before use; The preparation method of the first-level alkaline resin column, the second-level alkaline resin column, and the third-level alkaline resin column is as follows: wash the alkaline resin in water, pour it into a resin column for filling, drain the water, and obtain the first-level alkaline resin column. The second-level alkaline resin column and the third-level alkaline resin column are obtained by the same method, and NaOH solution is used to pass through the first, second, and third-level alkaline resin columns before use.

9. High-purity acetonitrile prepared by the method according to any one of claims 1 to 8.

10. The high-purity acetonitrile according to claim 9, characterized in that In the high-purity acetonitrile, no acrylonitrile and acrylic acid were detected, the removal rate of acrylonitrile was 100%, and the acetonitrile yield reached 99.9%.

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