WO1994026698A1 - High-purity acetonitrile and purification of crude acetonitrile - Google Patents

Abstract

High-purity acetonitrile which has less absorptions in the ultraviolet region of the wavelengths of 200-400 nm and is useable as a module-phase solvent in liquid chromatography, in particular, high-performance liquid chromatography. A simplified method of purifying crude acetonitrile either by bringing crude acetonitrile into contact with nascent oxygen and then with at least one compound selected from among basic substances and adsorbents, optionally followed by the separation and removal of low-boiling and high-boiling compounds, or by bringing crude acetonitrile into contact with nascent oxygen, separating and removing low-boiling and high-boiling compounds, and bringing the acetonitrile thus treated into contact with at least one compound selected from among basic substances and adsorbents.

Description

 Specification

 Method for purifying high-purity acetonitrile and crude acetonitrile

 The present invention relates to a method for purifying high-purity acetonitrile and crude acetonitrile. Specifically, high-performance liquid chromatography with an ultraviolet absorbance of wavelengths of 200 to 400 nm of 0.05 or less--a simple method for high-purity acetonitrile and crude acetonitrile for mobile phase solvents. In addition to a method for purification, a high-purity purification is carried out and industrially used as a mobile phase solvent for liquid chromatography, especially for high performance liquid chromatography, a wavelength of 200 to 40 O nm is used. The present invention relates to a purification method for obtaining high-purity acetonitrile with low absorption in the ultraviolet region. Background art

 Currently, commercially available acetonitrile is mainly produced as a by-product in the production of acrylonitrile or methacrylonitrile by the catalytic ammoxidation reaction of propylene or isobutene with ammonia and molecular oxygen. The product obtained is recovered and purified. Since acetonitrile obtained as a by-product contains many impurities, various methods for purification have been proposed.

For example, as a method for removing aryl alcohol in acetonitrile, a method of distilling and separating after reacting with sulfuric acid is disclosed in Japanese Patent Application Laid-Open No. 51-23218, which is an extractive distillation method in the presence of water. JP-A-5-143939-49 discloses a method of reacting with an aqueous solution of an alkali metal salt or an alkaline earth metal salt of hypochlorous acid. — It is disclosed in 3 2 5 18 As a method of removing oxazole in acetonitrile, a method of separating after reaction with molecular chlorine is disclosed in Japanese Patent Application Laid-Open No. 59-105556, which discloses extraction and distillation in the presence of water. A method for performing this is disclosed in Japanese Patent Application Laid-Open No. 55-143950. As a method for purifying acetonitrile, a method of distilling after reacting with a basic compound is disclosed in JP-A-56-54949, and a method using three distillation columns is disclosed in JP-A-56-549. It is disclosed in Japanese Patent Application Publication No. Sho 58-124. That is, the main impurities contained in acetonitrile are aryl alcohol, oxazole, acrylonitrile, etc. In order to remove these, it is necessary to combine conventionally disclosed methods, and the process must be carried out. It becomes very complicated. In this method, it was not possible to obtain acetonitrile having the absorbance of ultraviolet light having a wavelength of 200 to 400 nm of 0.05 or less, which is the object of the present inventors.

 East German Patent No. DD 2 172 212 A1 discloses a method of distilling after contact treatment with ozone, in which aryl alcohol, oxazole, lactone and the like are simultaneously decomposed and separated by distillation. A good way to get rid of it is disclosed. However, when the present inventors conducted additional tests, it was possible to reduce the absorbance of ultraviolet light having a wavelength of 200 to 400 nm of the acetate nitrile used as a raw material, but it was possible to reduce the absorbance of the wavelength of 200 to 400 nm. Acetonitrile having an ultraviolet absorbance of 0.05 or less could not be obtained.

 As described above, it is difficult to remove a small amount of impurities contained in crude acetonitrile by the conventionally disclosed method, and therefore, general commercially available acetonitrile is 200 to 400 Due to the high absorbance in the ultraviolet region of nm, it was unsatisfactory as a liquid chromatography mobile phase solvent used in this region, especially as a high-speed liquid chromatography mobile phase solvent. However, there is no disclosure of an industrial method for producing commercially available liquid chromatography acetonitrile for a mobile phase solvent, and the technical development has been awaited.

Crude acetonitrile contains impurities derived from its manufacturing method, and therefore has absorption in the ultraviolet region of wavelength 200 to 400 nm, but the ultraviolet absorption in this region is mainly due to the double impurities. This is due to bonding. For example, C = C double bond, C = 0 group, COOH carboxyl group, CHO aldehyde group, C = N double bonds, N - 0 nitroso group, have a bond or a functional group such as N 0 ₂ nitro groups You Compounds have absorption in this region, specifically, allylic alcohol, oxazole, acrylonitrile, methacrylonitrile, cis and trans crocrotritolyl, acrylic acid, acrylic acid Methyl, methacrylic acid, methyl methacrylate, acetic acid, acrolein, methacrolein, and acetone are applicable. It is very difficult to separate and remove such compounds to obtain acetonitrile having an absorbance at a wavelength of 200 to 400 nm of 0.05 or less. For example, in order to reduce the absorbance of acetonitrile at a wavelength of 200 nm to 0.05 or less, acrylonitrile in acetonitrile is 1.5 ppm or less, and oxazole is 0.8 ppm or less. Acrylonitrile is less than 0.2 ppm, methacrylonitrile is less than 0.2 ppm, cis-crotonitrile is less than 0.2 ppm, acrylic acid is less than 0.2 ppm, and methyl acrylate is 0. .2 ppm or less, acetic acid must be 30 ppm or less, and the same applies to other impurities. In practice, most of these compounds coexist in acetonitrile, so the limit value of each compound is even smaller, so that high-purity acetonitril can be obtained. Requires advanced separation and purification technology.

 A first object of the present invention is to disclose a high-purity acetate nitrile for high-performance liquid chromatography and a mobile phase solvent having an absorbance of ultraviolet light having a wavelength of 200 to 400 nm of 0.05 or less. A second object of the present invention is to provide a simple method for purifying crude acetonitrile and a more advanced purification to industrially carry out liquid chromatography-mobile phase solvents, especially high-performance liquid-mouth chromatography-mobile phase solvents. The present invention discloses a purification method for producing acetonitrile having an absorbance of ultraviolet rays having a wavelength of from 200 to 400 nm and having a wavelength of not more than 0.05.

The present inventors have conducted a detailed study on a method of contact treatment with ozone, and found that acid and permanganate reducing substances are generated by the contact treatment with ozone, and these are basic substances and / or They grasped that they were removed by contact with the adsorbent, and found a simple purification method that was the object of the present invention. Even more surprisingly, the liquid treated with ozone was brought into contact with one or more basic substances and adsorbents. By removing the low-boiling compounds and high-boiling compounds contained in the acetonitrile later, an acetonitrile having an ultraviolet absorbance of 0.05 to 400 nm or less of ultraviolet light having a wavelength of 0.05 or less can be obtained. Thus, the present invention has been completed. Disclosure of the invention

 That is, the present invention provides a method for purifying crude acetonitrile.

 (1) a first step of contacting crude acetonitrile as a raw material with nascent oxygen; and

 (2) a second step of bringing the acetonitrile that has passed through the first step into contact with at least one substance selected from a basic substance and an adsorbent; and, if necessary,

 (3) The third step of separating and removing low-boiling compounds and high-boiling compounds contained in the acetonitrile that has passed through the second step, or

 (4) After the first step, perform the third step, and then perform the second step

This is a method for purifying crude acetonitrile, characterized by purifying the crude acetonitrile in the following order.

 The crude acetonitrile as a raw material in the present invention includes acetonitrile having a light absorbance of ultraviolet light having a wavelength of 200 nm of 0.1 or more, propylene, isobutene or tertiary butanol, and ammonium nitrate. Crude acetonitril, which is obtained as a by-product when acrylonitrile or methacrylonitrile is produced by catalytic ammoxidation reaction with oxygen, can be used.

 As the crude acetonitrile of the raw material, a crude acetonitril having an absorbance of 0.1 or more for ultraviolet light having a wavelength of 200 nm can be used, and preferably, a crude acetonitrile having a wavelength of 200 nm is used. Crude acetonitrile having an ultraviolet absorbance of 0.1 or more and 5 or less, more preferably crude acetonitrile having an absorbance of ultraviolet light of a wavelength of 200 nm of 0.1 or more and 3 or less. Is good.

Further, the present invention does not particularly limit crude acetonitrile as a raw material, and crude acetonitrile produced by another production method can also be used as a raw material. Specifically, ethane, propane, butane, isobutane, pen Crude acetonitrile induced by an ammoxidation reaction of a saturated hydrocarbon compound such as benzene, an aromatic compound such as carbon monoxide, toluene, or xylene.

 According to the method of the present invention, the crude acetonitrile having an absorbance of ultraviolet light having a wavelength of 200 nm of 0.1 or more is used as a raw material, and the absorbance of ultraviolet light having a wavelength of 200 to 400 nm is 0.05 or less. Acetonitrile can be obtained.

 Furthermore, crude acetonitrile having an absorbance of ultraviolet light having a wavelength of 200 nm less than 0.1 can be used as a raw material. However, the use of these raw materials is not an attractive method, mainly because of the small effect from an economic point of view.

 In the present invention, the absorbance of acetonitrile for ultraviolet light is a value measured using an Iseki cell having an optical path length of 10 mm and distilled water at the detection wavelength as a control. The first step of the present invention is a step of contacting crude acetonitrile with nascent oxygen. The purpose of this step is to decompose impurities having double bonds, especially aryl alcohol, oxazole, acrylonitrile, etc., which are difficult to remove by methods such as distillation, adsorption or reaction, by contact with nascent oxygen. It is to convert the compound into a compound that can be easily separated and removed in the subsequent steps. Compounds that generate nascent oxygen include permanganic acid or salts thereof, such as permanganate potassium lime, peroxides such as hydrogen peroxide, sodium peroxide, barium peroxide, oxyacid or salts thereof. For example, sodium hypochlorite, potassium hypochlorite, sodium hypoiodite, potassium hypoiodite, sodium hypobromite, sodium hypochlorite Lithium, sodium chlorate, sodium chlorate, sodium iodate, sodium iodate, sodium bromate, sodium bromate, sodium perchlorate , Potassium perchlorate, perchloric acid, periodic acid, sodium periodate, potassium periodate, ozone-containing gas, etc., and preferably ozone-containing gas . Through this step, the effect of separating and removing impurities in the subsequent steps can be significantly improved.

The ozone-containing gas used in the present invention is obtained by supplying air or oxygen or an oxygen-containing gas to an ozone generator, and is used for contact with crude acetate. It can also be used after diluting it with a gas such as nitrogen, carbon dioxide or air. The concentration of ozone in the ozone-containing gas is from 0.01 to 5.0 V, preferably from 0.1 to 2.0 V. If the ozone concentration is too low, the time required for contact with the crude acetonitril increases, and the efficiency increases due to the increase in the size of the reactor and the accompanying loss of acetonitril due to the supplied gas. Not. Also, it is difficult to increase the ozone concentration to 5 V 0 1% or more due to the performance of the ozone generator. The temperature at which the crude acetonitrile is brought into contact with the ozone-containing gas is 140 to 80 ° C, preferably 10 to 40 ° C. If the temperature is too low, there are problems such as a slow reaction rate and precipitation of trace components. If the temperature is too high, an excessive reaction proceeds and the yield of acetonitrile decreases.

 The pressure at which the crude acetonitrile is brought into contact with the ozone-containing gas may be reduced pressure, normal pressure, or pressurized pressure, but is preferably in the range of normal pressure to 10 atm.

 The contact between the crude acetonitrile and the ozone-containing gas can be performed in a batch system or a continuous system. The batch method can be carried out in a single-stage or multi-stage contact tank having a stirring device or a bubble tower, but is preferably performed in a contact tank having a stirring device to improve gas-liquid contact. New Furthermore, in order to improve the contact between the crude acetonitrile and the ozone-containing gas, the ozone-containing gas is preferably supplied as small bubbles from one or more nozzles into the acetonitrile. . Further, the ozone-containing gas is preferably supplied to a position below or beside the stirring blade, and the optimum position is determined by observing the stirring state of the acetonitrile depending on the structure of the tank and the blade. And the number can be determined.

The contact between the crude acetonitrile and the ozone-containing gas in the batch method depends on the amount of impurities contained in the crude acetonitrile, but the volume of the acetonitrile contacted with the ozone-containing gas is different. It is preferable to supply a gas volume of 1 to 1000 times, preferably 100 to 1000 times, for 1 to 300 minutes, preferably 10 to 120 minutes. . If the supply time is too short, the reaction between the ozone and the impurities will be insufficient, and the loss due to the entrainment of acetonitril due to the high gas flow rate will occur. If the supply time is too long, there is no advantage from the viewpoint of productivity, and an excessive oxidation reaction proceeds.

 The supply time of the ozone-containing gas can also be determined by analyzing the ozone concentration in the exhaust gas. Specifically, it is preferable to supply the ozone-containing gas until the ozone concentration in the exhaust gas becomes 80% or more, preferably 90% or more of the ozone concentration of the supplied gas. For analysis of the ozone concentration, a continuous analyzer using an iodine titration method, an ultraviolet absorption method, a chemiluminescence method, or the like can be used.

 In the continuous method, the reaction can be carried out in a packed tower, a wet wall tower, a bubble tower, or the like, but it is preferably carried out in a packed tower. As the packing material for the packed tower, Raschig ring, wrestling ring, Berlassador, interlock saddle, teralet packing, pole ring, McMahon packing, Dixon ring, etc. can be used. . These fillers can be made of a material such as porcelain, metal, plastic, or carbon. The contact between the crude acetonitrile and the ozone-containing gas can be carried out in countercurrent or cocurrent, but it is preferable to make contact in countercurrent. In the packed tower, a liquid redistribution plate can be provided at an appropriate height to increase the gas-liquid contact efficiency. The ratio of the ozone-containing gas to the crude acetonitrile is preferably 1 to 1000, preferably 10 to 100, by volume, and flooding occurs according to the characteristics of the packed tower. No value is chosen.

 The second step of the present invention is a step of bringing the acetonitrile that has passed through the first step into contact with at least one substance selected from a basic substance and an adsorbent. The purpose of this step is to convert impurities contained in the acetonitrile that has passed through the first step into compounds that can be easily separated, or to perform adsorption separation.

 The contact of the acetonitrile with the basic substance and the adsorbent in the second step of the present invention is at a temperature of 140 to 80 ° C, preferably at a temperature of 5 to 60 ° C. More preferably, it is carried out at a temperature of 10 to 40. As the basic substance in the present invention, a liquid or solid basic substance is used.

Liquid basic substances include Li, Na, K, Rb and Alkali metals. Is a compound selected from the group consisting of hydroxides of Cs, carbonates or bicarbonates, hydroxides of Mg, Ca, Sr or Ba as alkaline earth metals, ammonia or amine, or The aqueous solution or the solution can be used.

 The amine used here has a boiling point of at least 5 ° C, preferably 1 ° C, compared to the boiling point of acetonitrile in order to facilitate separation and removal in the subsequent distillation step. It is preferable to use an amine separated by 0 ° C or more, specifically, methylamine, dimethylamine, trimethylamine, ethylamine, getylamine, triethylamine, Propylamine, isopropylamine, dipropylamine, tripropylamine, s-butylamine, t-butylamine, dibutylamine, triptylamine, pentylamine, t 1-Pentylamine, hexylamine, heptylamine, octylamine, ethylenediamine, 1,2—pan mouth, 1,3—propanediamine, ethanolamine, Aliphatic amines such as ethanolamine and triethanolamine, or aromatics such as aniline, pyridine, quinoline, 0-toluidine, m-toluidine, p-toluidine Family.

 The solvent used for the solution used here has a boiling point of 5 ° C or more compared to the boiling point of acetonitrile in order to facilitate separation and removal in the next distillation step. It is preferable to use a solvent which is separated by 10 or more. Specifically, methanol, 1-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3 —Pennol, ethylene glycol, 1,3—dioxane, 1,4-dioxane, 1,2—propanediol, 1,3—aliphatic alcohols such as propanediol, or pentane, hexane, octane And saturated aliphatic hydrocarbons such as nonane and decane. In addition, it is also possible to use acetonitrile itself as a solvent.

The concentration of the basic substance in these aqueous solutions or solutions can be arbitrarily set at a concentration equal to or lower than the saturation solubility, but may be a slurry. The amount of addition of these liquid basic substances may be such that the pH value of an aqueous solution obtained by diluting the acetate to 1/10 with water becomes 5 or more, but it is preferable. Is 5-9, more preferred It is better to control it to be 6-8.

 The contact between the acetonitrile and the liquid basic substance is carried out by injecting into a pipe with a line mixer or a single- or multi-stage contact tank with a stirring device to promote the reaction. It is preferable to add the compound. The added liquid basic substance forms a salt with an acid such as carboxylic acid and precipitates as a sticky precipitate.Therefore, in order to prevent troubles due to clogging in the next distillation step, filtration and sedimentation are performed. An operation of separating these precipitates by separation or the like is required. If water is contained in the basic substance added as a liquid, the water must be removed to form an azeotropic composition with acetonitril when the water is separated and removed in the next distillation step. At the same time, acetonitrile is also removed, resulting in a problem that the recovery rate of acetonitrile is reduced.

 Further, an ammonia gas or an ammonia-containing gas as a basic substance can be supplied into the acetonitril to cause a reaction. In order to improve the contact between the ammonia gas or the gas containing ammonia and the acetonitrile and promote the reaction, small bubbles are supplied from one or more nozzles into the acetonitrile, or stirring is performed. It is good to use the method. The supply amount of ammonia or ammonia-containing gas may be any amount as long as the pH value of an aqueous solution obtained by diluting the acetonitrile to 110 with water is 5 or more, preferably 5 to 9, more preferably 5 to 9. Should be controlled to be 6 to 8.

Solid basic substances include anion exchange resins, alkali metal hydroxides, carbonates or bicarbonates, alkaline earth metal oxides, hydroxides, or carbonates, and mixtures of different metal oxides. A solid base, a substance in which an alkali metal or alkaline earth metal compound is supported on a carrier, activated carbon, and the like. As the anion exchange resin of the present invention, a porous or gel type strongly basic anion exchange resin or a weakly basic anion exchange resin can be used. Either an ion exchange resin for an aqueous solution or an ion exchange resin for a non-aqueous solution can be used. Strongly basic anion exchange resin regenerates exchange groups such as trimethylammonium group and dimethylethanol group by regeneration treatment. Arbitrary preferable to use an ionic form as the OH-type or C 0 ₃ form. Further, the Jakushio group anion exchange resin arbitrariness preferred to use after performing a reproduction process 1-3 Kyua Mi Bruno exchange group such as N a OH, with NH ₄ 0 H like. After performing an exchange group regeneration treatment, these anion exchange resins are brought into contact with a sufficient amount of acetonitrile and washed to remove water and impurities contained in the ion exchange resin before use. Good to use.

 Specific examples of the solid basic substance of the present invention include hydroxides, carbonates or bicarbonates of alkali metals Li, Na, K, Rb, and Cs, and alkaline earths. Oxides, hydroxides or carbonates of the metals Mg, Ca, Sr, and Ba, silica magnesia, which is a mixture of different metal oxides, calcium silica, strontium silica, and silicon Examples of the carrier include oxides, hydroxides, carbonates, or bicarbonates, which are compounds of barium oxide, an alkali metal, or an alkaline earth metal. Activated carbon, silica, alumina, titania or zirconia is used, and the loading amount is 0.01 to 50 wt%, preferably 0.1 to 10 wt%.

Furthermore, as solid basic substances, N ₂₀ ,? ^ 1 ^ or 211_Rei _{1 2 - 1 ^^ 1 4 C} 1 - C 0 2 in is activated can also be used activated carbon was expressed basified. As the adsorbent, activated carbon, activated alumina, silica gel, synthetic zeolite, natural zeolite, adsorption resin, natural clay mineral, silica alumina, silica magnesia, silica polia and the like are used.

 Solid basic substances and Z or adsorbents can be handled as powders or granules, the size of which is between 0.01 and 100 mm, preferably between 0.01 and 2 A thing of 0 mm is good. Further, the powder can be used as a cylindrical or spherical molded body by tableting or the like.

 The contact between the basic substance and Z or the adsorbent with the acetonitril can be carried out in a continuous manner or in a batch manner. However, for industrial use, the continuous manner is preferred.

As a continuous method, a solid basic substance is filled in a part of a packed tower or pipe. Then, it can be supplied and contacted with the acetonitrile. Further, the space velocity SV is preferably operated at 0.001 to 100 (lZmin), preferably at 0.01 to 100 (1 / in).

 The batch method can be carried out in a contact tank equipped with a stirring device or a shaking device. The contact time is between 0.1 and 1000 minutes, preferably between 1 and 120 minutes.

 When the solid base and the adsorbent are used in the second step, the separation of the solid base and / or the adsorbent from acetonitrile becomes unnecessary, and the present invention can be carried out without the separation and removal step in the third step. The first purpose, simple acetonitrile purification, can be performed. That is, a simple method of purifying acetonitrile by simply passing through a packed bed composed of a solid base or an adsorbent without using a distillation column disclosed in East German Patent No.DD 2172 212 A1 is disclosed. Things. However, in order to obtain an acetonitrile having an absorbance of ultraviolet light having a wavelength of 200 to 400 nm of 0.05 or less, which is the second object of the present invention, the first step and the second step are continued. Processing by the third step is required.

 The third step of the present invention is a step of separating and removing low-boiling compounds and high-boiling compounds in acetonitrile that have passed through the first step or the second step. The purpose of this step is to separate and remove impurities such as compounds that cause ultraviolet absorption contained in acetonitrile, and that the absorbance of ultraviolet light at a wavelength of 200 to 400 nm is less than 0.05. Is to get acetonitrile.

 The method of separation and removal is selected from a distillation method and a membrane separation method, and a distillation method is particularly preferable as an industrial separation method.

 As the distillation column of the present invention, a tray column or a packed column is used. Examples of the tray tower include a cross-flow contact type with a downcomer and a countercurrent contact type without a downcomer. In addition, a bubble bell type, a perforated plate type, a valve type, or the like can be used as the tray opening. The number of stages in this distillation column is not particularly limited as long as it is at least 10 stages, but preferably 30 to 80 stages.

Examples of packed towers include lashing rings, dressing rings, and polish A tower filled with a wool ring, berl saddle, interlock saddle, teralet hacking, dixon ring or McMahon packing can be used. As the material of the filler, it is possible to use those made of porcelain, metal, plastic or carbon. Further, the packing tower may be provided with a liquid redistribution plate at an appropriate height to enhance the gas-liquid contact efficiency.

 In the present invention, as a method for separating and removing a compound having a low boiling point and a compound having a high boiling point as compared with acetonitrile, a method using two distillation columns may be mentioned. Specifically, a method in which low-boiling compounds are separated and removed from the top in the column I, and high-boiling compounds are separated and removed in the second column from the bottom to obtain purified acetonitrile from the top, or There is a method in which a high-boiling compound is separated and removed from the bottom in one column, and a low-boiling compound is separated and removed from the top in a second column to obtain purified acetonitrile from the bottom or the upper part. In order to improve the quality of the toluene, it is preferable to first separate and remove water by azeotropic distillation with acetonitrile, and then take out acetonitrile from the top in the second column. Therefore, a method is preferred in which the low-boiling compound is separated and removed from the top in the first column, the high-boiling compound is separated and removed from the bottom in the second column, and purified acetonitrile is obtained from the top. Water is generated by the oxidation reaction with ozone in addition to that contained in crude acetate nitrile.

In addition, the low-boiling compound and the high-boiling compound can be separated and removed in a single distillation column. Specifically, the acetonitrile is supplied to an intermediate portion of the distillation column, a low-boiling compound is extracted from the top of the distillation column, and a high-boiling compound is extracted from the bottom of the distillation column. This is a method of obtaining purified acetonitrile from above or below the supply position, and preferably a method of obtaining purified acetonitrile from above the supply position of the acetonitrile. In these separation and removal operations, the reflux ratio and the amount of low-boiling compounds and high-boiling compounds withdrawn can be determined as conditions for obtaining purified acetonitrile that meets the purpose. The withdrawal amount of the top containing the low-boiling compound and the withdrawal amount of the bottom containing the high-boiling compound are each 1% or more, preferably 5% or more, based on the supplied acetonitrile. Extraction amount from top and bottom If the amount is small, the absorbance of ultraviolet light having a wavelength of 200 to 400 nm may not be less than 0.05 due to a trace amount of impurities contained in the extracted acetonitrile.

 Further, even if three or more distillation columns are used, the low-boiling compound and the high-boiling compound can be separated and removed, but this is not an economically effective method.

 These distillation operations can be performed at any of reduced pressure, normal pressure, and increased pressure, but usually the range of normal pressure to 10 atm is preferable.

 In the operation management of these three processes, precise and advanced operation management is necessary especially for obtaining acetonitrile used for high-speed liquid chromatography-mobile phase solvent. As one of the methods, it is effective to measure the raw material of crude acetonitril and the physical properties of each process using near infrared spectroscopy and to control the operation. When the solid base and Z or the adsorbent are used for purification in these three steps, the object of the present invention can be achieved even if the order of the second step and the third step is changed. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a diagram showing an ultraviolet absorption spectrum of purified acetonitrile.

 FIG. 2 is a view showing an ultraviolet absorption spectrum of acetonitrile as a raw material. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

 [Example 1]

As the raw material acetonitrile, the absorbance of ultraviolet light at 200 nm is 1.560, acrylonitrile as impurities 2.8 ppm, allylic alcohol 5.0111, acid 1.5 ppm, The following operation was performed using acetonitrile having a permanganic acid fading rate of 29%, which is an index of the amount of permanganate reducing substances. I got it.

As a first step, a 30 mm diameter ozone contact tower was filled with a porcelain lashing ring with an outer diameter of 5 mm, an inner diameter of 2 mm and a height of 5 mm to a height of 41 mm. The acetonitrile is fed from the top of the tower at 300 m £ / Hr at a temperature of 20 under atmospheric pressure, and ozone is added at 0.24 vol% (5.1 g / Nm ³ “Nm ³ ” represents 180 Nr of ozone-containing gas containing m ³ (cubic meter) at 0 ° C and 1 atm (“N £” is 0 and £ (lit) at 1 atm. Torr) (gas-liquid ratio = 600). Acetonitrile contacted with ozone was extracted from the bottom of the ozone contact tower. Acrylonitrile and aryl alcohol in the extracted acetonitrile were not detected, but the acid concentration increased to 105 ppm and the permanganate discoloration rate was 100%. Had risen. Next, as a second step, a column having a diameter of 20 mm filled with 50 m ^ filled with a non-aqueous porous weakly basic anion exchange resin (trade name Amberlist A—21) was prepared. The acetonitril that had passed through the step 1 was continuously supplied, and brought into contact at a temperature of 20. The absorbance of the finally obtained acetonitrile in ultraviolet light at 200 nm is 1.620.According to the analysis by gas chromatography, acrylonitrile and acryl alcohol are below the detection limit. there were. The acid content was 0.9 ppm, and the permanganic acid fading rate was 0%. As is clear from the results, the treatment in the first step decomposes acrylonitrile and aryl alcohol, but increases acid and permanganate reducing substances. It is clear that the acid and permanganate reducing substances have been removed by the treatment in the second step. Although this operation was performed continuously for 200 hours, the operation was simple and the operation was stable. At this time, the recovery of purified acetonitril was as high as 90% of the supplied acetonitril. The ultraviolet absorption spectrum was measured using a quartz cell with an optical path length of 10 mm and a spectrophotometer 288 A manufactured by Hitachi using distilled water as a control. The gas chromatographic analysis was performed using a Yokogawa Gas Chromatograph HP-5890, with a capillary column inner diameter of 0.25 mm * length of 50 m using silicon OV-1 as the packing material. Column temperature first at 40 ° C 5 After maintaining the temperature for 10 minutes, the temperature was raised to 200 ° C. at a rate of 10 ° C.Z, and finally maintained at this temperature for 10 minutes. The acid analysis was performed in accordance with JISK8001 5.6 (1). For the permanganate reducing substance, add 0.1 m £ 0.1 N potassium permanganate to 10 g of sample, shake and mix in a cool dark place for 30 minutes, referring to the method described in JISK 8032 After standing, the permanganic acid fading rate was measured using a UV 2000 model manufactured by Shimadzu Corporation and used as an index of the permanganate reducing substance.

 Permanganic acid fading rate = (1-(A / B)) X 1 0 0

 A: Absorbance after 30 minutes

 B: Absorbance immediately after start

 Wavelength: 5 4 5 nm

 [Example 2]

 In the second step of Example 1, a mixture of aluminum nitrate and silica sol in an atomic ratio of A1: Si = 1: 1 as an adsorbent was evaporated to dryness, and then calcined at 500. Purified acetonitrile was obtained by performing the same operation as in Example 1 except that 35 g of silica alumina was used. This acetonitrile had an absorbance of ultraviolet light of a wavelength of 200 nm of 1.480, an acid of 1. Oppm and a permanganate acid fading rate of 7%.

 [Example 3]

 Purified acetonitrile was obtained by performing the same operation as in Example 1 except that 50 m ^ was used as the adsorbent in the second step of Example 1. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 1.500, the acid was 1.2 ppm, and the permanganic acid fading rate was 5%.

 [Example 4]

The raw material acetonitrile has an absorbance of 200 nm ultraviolet ray of 1.703, and the impurities are acrylonitrile 3.5 ppm, methacrylonitrile 8 ppm, and allylic alcohol 8 ppm. The following operation was performed using acetonitrile containing 2 ppm of oxazole. As a first step, a 30 mm diameter ozone contact tower was filled with a porcelain lashing ring with an outer diameter of 5 mm, an inner diameter of 2 mm and a height of 5 mm to a height of 41 mm. At atmospheric pressure and at a temperature of 20 ° C, the acetonitrile is supplied from the top of the tower at 300 m £ ZHr, and ozone is supplied from the bottom of the tower at 0.24 vol% (5.1 g / Nm ³ ) Containing ozone was supplied at 180 N £ / Hr (gas Z liquid ratio = 600). Acetonitrile contacted with ozone was extracted from the bottom of the ozone contact tower.

 In the second step, a non-aqueous, porous, weakly basic anion exchange resin (trade name Amberlyst A—21) was packed in a 50 mm column packed with 20 mm diameter, The acetonitrile was then supplied continuously and brought into contact at a temperature of 20. (Next, as a third step, a distillation apparatus with a diameter of 40 mm and a perforated plate system with a total of 65 stages was used. The 10th stage is continuously supplied with the acetate tril which has passed through the second step, the operation is performed at a reflux ratio of 16 with the top pressure set to atmospheric pressure, and the base containing the low boiling point compounds is operated from the top. Tonitrile was extracted in an amount of 20% of the supplied amount, and acetonitrile containing high-boiling compounds was extracted from the bottom of the column in an amount of 10% of the supplied amount, and refined from the 40th stage. Tonitrile was obtained in an amount of 70% of the supplied amount, and the recovery of acetonitrile was 70%.

 The absorbance of ultraviolet light at a wavelength of 200 nm of this acetonitrile was 0.021, and the absorbance of ultraviolet light at 210 to 400 nm was not more than 0.013. Analysis by gas chromatography showed that acrylonitrile, methacrylonitrile, acryl alcohol and oxazole were below the detection limit.

 Although this operation was continuously performed for 200 hours, the operation was stable without any problem. Then, as operation management, the crude acetonitrile of the raw material and the first, second, and third steps were analyzed online by a NIR Systems Corporation 6500 type near-infrared spectrometer. The operation was managed and a stable product was obtained.

 FIGS. 1 and 2 show the ultraviolet ray absorption spectrum of the purified acetonitrile and the acetonitrile used as a raw material, respectively.

[Example 5] As the basic substance in the second step of Example 4, a gel-type strongly basic anion exchange resin (trade name: IRA-400) in which the ionic form was converted to the OH form was 50 m A purified acetonitrile was obtained by performing the same operation as in Example 4 except for using. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 0.040, and the absorbance for ultraviolet light at 210 to 400 nm was 0.025 or less.

[Example 6]

 The same procedure as in Example 4 was carried out except that 30 g of granular CaC0 was used as the basic substance in the second step of Example 4, to obtain an acetonitrile. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 0.034, and the absorbance for ultraviolet light of 210 to 400 nm was 0.021 or less.

[Example Ί]

 Acetonitrile purified by the same procedure as in Example 4 except that 40 g of a silicic acid carrying 5.0 wt% MgO was used as the basic substance in the second step of Example 4. I got a toll. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 0.030, and the absorbance for ultraviolet light from 210 to 400 nm was 0.019 or less.

[Example 8]

 The same operation as in Example 4 was performed up to the second step using 50 g of activated carbon carrying 2.0 wt% of KOH as the basic substance in the second step of Example 4.

In the third step, using two distillation columns having a diameter of 32 mm and a perforated plate system with a total of 60 stages, the acetonitrile obtained in the second step is transferred to the 40th stage of the first column. By feeding at 25 Qm £ / Ur and operating at a reflux ratio of 12 with the top pressure at atmospheric pressure, acetonitrile extracted from the bottom of the column in an amount of 80% of the feed amount was The mixture was fed to the 20th stage of the column, operated at a reflux ratio of 3, and 70% of the supplied amount of purified acetonitril was extracted from the top of the column. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 0.043, and the absorbance of ultraviolet light for 210 to 400 nm was 0.026 or less. [Example 9]

 In the second step of Example 4, as an adsorbent, a mixture of aluminum nitrate and silica sol at an atomic ratio of A 1: S i = l: 1 was evaporated to dryness, and then calcined at 500 ° C. Except that 35 g of the silica alumina thus obtained was used, the same operation as in Example 4 was performed to obtain purified acetonitrile. The absorbance of this acetonitrile for ultraviolet rays at a wavelength of 200 nm was 0.039, and the absorbance for ultraviolet rays of 210 to 400 nm was not more than 0.024.

 [Comparative Example 1]

 In Example 4, acetonitrile was obtained by performing the same operation except that contact with ozone in the first step was not performed. The absorbance of this acetonitrile for ultraviolet rays at a wavelength of 20 nm was 1.601.

 [Comparative Example 2]

 In Example 4, acetonitrile was obtained by performing the same operation except that the contact with the basic substance in the second step was not performed. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 0.157.

 [Comparative Example 3]

 In Example 4, the same operation was performed except that the distillation in the third step was not performed, to obtain acetonitrile. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 20 nm was 1.451.

 As can be seen from these three comparative examples, it is not possible to obtain acetonitrile having an absorbance of ultraviolet light having a wavelength of 200 nm or less of 0.05 if at least one of the three steps is performed.

 [Comparative Example 4]

 In Example 4, operations were performed in the order of the second step, the third step, and the first step to obtain acetonitrile. The absorbance of this acetonitrile for ultraviolet rays at a wavelength of 200 nm was 1.655.

 [Comparative Example 5]

In Example 4, the operations were performed in the order of the second step, the first step, and the third step. I got an acetonitrile. The absorbance of this acetonitrile at a wavelength of 200 nm for ultraviolet light was 0.219.

 [Comparative Example 6]

 In Example 4, the operation was performed in the order of the third step, the first step, and the second step to obtain an acetonitrile. The absorbance of this acetonitrile for ultraviolet rays at a wavelength of 200 nm was 1.552.

 [Comparative Example 7]

 In Example 4, the operation was performed in the order of the third step, the second step, and the first step to obtain acetonitrile. The absorbance of this acetonitrile for ultraviolet rays at a wavelength of 200 nm was 1.550.

[Example 10]

Acetonitrile, which is obtained as a by-product during the production of acrylonitrile by the propylene ammoxidation reaction, is purified and recovered as a raw material acetonitrile. The following operation was performed using acetonitrile having an ultraviolet absorbance of 0.503 and containing acrylonitrile as impurities at 1 ppm, oxazole at 2 ppm, and aryl alcohol at 20 ppm. As a first step, 150 ml of the acetonitrile was placed in a 2 £ round bottom flask with a stirrer, and 0.24 vol% (5.1 / The ozone-containing gas containing Nm ³ ) was supplied at 3 N £ Zmin for 90 minutes. The pH value of an aqueous solution obtained by diluting acetonitrile to 1Z10 with water after this operation was 6.0.

 As a second step, 3.3 g of a 50 wt% aqueous NaOH solution was added to the above acetonitrile, and the mixture was stirred for 20 minutes. At this time, a white sticky substance precipitated in the flask, but was separated by filtration. The pH value of an aqueous solution obtained by diluting this acetonitrile to 110 with water was 7.4.

As a third step, using the two distillation apparatuses used in Example 8, the acetonitrile obtained in the second step was transferred to the 40th stage of the first column at 250 m / H and supply from the bottom by operating at a reflux ratio of 12 with the top pressure at atmospheric pressure Acetonitrile extracted in an amount of 75% of the amount was supplied to the second column of the second column, operated at a reflux ratio of 3 and purified from the top of the column with an amount of 65% of the supplied amount. I pulled out the Settrill. The absorbance of ultraviolet light at a wavelength of 200 nm of this acetate nitrile was 0.025, and the absorbance of ultraviolet light at 210 to 400 nm was 0.016 or less.

 Gas chromatographic analysis showed that acrylonitrile, oxazole and aryl alcohol were below the detection limit.

[Example 11]

 In the second step of Example 10, ethanolamine was added. Purified acetonitrile was obtained in the same manner as in Example 10, except that the pH of an aqueous solution obtained by diluting this acetonitrile with water to 10 was adjusted to 9.0. . The absorbance of ultraviolet light at a wavelength of 200 nm of this acetonitrile was 0.027, and the absorbance of ultraviolet light at 210 to 400 nm was 0.013 or less.

[Example 12]

 8 parts by weight of the raw material acetonitrile used in Example 1 was added to 2 parts by weight of the acetate nitrile obtained in Example 4, and the absorbance of ultraviolet light at a wavelength of 200 nm was 1.4. Tonitrile was prepared, and the starting material was used as a raw material, and the acetonitrile was put into the same apparatus as in the first step of Example 10 at a rate of 1,500 m. A gas containing ozone was supplied at 3 £ in and contacted for 240 minutes. This acetonitrile was subjected to the same operation using the same apparatus as in the second and third steps of Example 4 to obtain purified acetonitrile. The absorbance of ultraviolet light at a wavelength of 200 nm of this acetate tube was 0.045, and the absorbance of ultraviolet light at 210 to 400 nm was 0.028 or less.

[Example 13]

As a raw material of acetonitrile, acetonitrile obtained as a by-product in the production of acrylonitrile by an ammoxidation reaction of propylene is recovered and purified. Add 200 m of acetonitrile having an absorbance of 0.36 nm ultraviolet ray to a round bottom flask with a shaker of 3 £ at 20 ° C. Ozone-containing gas containing 0.24 vo 1% of ozone was supplied at 3 N ^ / in, and when the ozone concentration in the exhaust gas reached 0.20 V 01%, the ozone-containing gas was supplied. Stopped. At this time, the ozone concentration in the exhaust gas was 83% of the ozone concentration in the supply gas. This acetonitrile was subjected to the same operation using the same apparatus as in the second and third steps of Example 4 to obtain purified acetonitrile. The absorbance of this acetonitrile at ultraviolet wavelength of 200 nm was 0.040, and the absorbance of ultraviolet light at 210 to 400 nm was 0.026 or less.

[Example 14]

 As the first step of Example 4, the acetonitrile 1 was placed in the round bottom flask equipped with a stirrer 2 and Wako Pure Chemical's special grade potassium permanganate 1 was used as a compound to generate nascent oxygen. .09 g was added, and the mixture was stirred at 60 ° C for 2 hours. Thereafter, simple distillation was performed to obtain acetonitrile containing no potassium permanganate. Next, the second and third steps were performed in the same manner as in Example 4 to obtain purified acetonitrile. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 0.045, and the absorbance for ultraviolet light of 210 to 400 nm was 0.027 or less.

[Example 15]

 In the second step of Example 10, a mixture of aluminum nitrate and silica sol in an atomic ratio of A1: Si = 1: 1 as an adsorbent was evaporated to dryness, and then calcined at 500 ° C. The same operation as in Example 10 was performed except that 10 g of the silica alumina thus obtained was used to obtain purified acetonitrile. The absorbance of this acetonitrile for ultraviolet rays at a wavelength of 200 nm was 0.020, and the absorbance for ultraviolet rays of 210 to 400 nm was 0.010 or less.

[Example 16]

An acetate unit purified by the same operation as in Example 13 except that synthetic zeolite (trade name: molecular sieve-4A) 50 m £ is used as an adsorbent in the second step of Example 13 I got a lil. The absorbance of ultraviolet light at a wavelength of 200 nm of this acetate is 0.011, and the absorbance of ultraviolet light at a wavelength of 210 nm to 400 nm. The luminous intensity was less than 0.05.

 Lipid analysis was performed using this acetonitril. When studying biologically active phospholipids at the molecular level, it is necessary to analyze very small amounts of lipids in various biological samples with high sensitivity and accuracy.Acetonitrile used for high-performance liquid chromatography-mobile phase Requires high purity. However, commercially available acetonitrile for liquid chromatography and acetonitrile of Comparative Example 2 purified according to East German Patent No. DD 217 212 A1 have high impurity levels and lipid analysis. Was unsuitable for However, this acetonitrile having an absorbance of 0.011 for ultraviolet rays having a wavelength of 200 nm was remarkably low in impurity level and was suitable for lipid analysis. Peptide purification was performed using this acetonitrile. High purity is required for preparative liquid chromatography-mobile phase acetonitrile used for peptide purification. However, commercially available acetonitrile for liquid chromatography and acetonitrile of Comparative Example 2 purified according to Tohoku's patent DD2172212A1 have high impurity levels and peptides. Not suitable for purification. However, this acetonitrile having an absorbance of 0.011 for ultraviolet rays having a wavelength of 200 nm was remarkably low in impurity level and was suitable for peptide purification.

[Example 17]

 Purified acetonitrile was obtained by performing the same operation as in Example 13 except that 50 ml of activated carbon was used as the adsorbent in the second step of Example 13. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 0.013, and the absorbance for ultraviolet light of 210 to 400 nm was not more than 0.006.

[Example 18]

 In Example 4, the first step, the third step, and the second step were performed in this order to obtain purified acetonitrile. The absorbance of this acetonitrile for ultraviolet light at a wavelength of 200 nm was 0.048, and the absorbance for ultraviolet light of 210 to 400 nm was 0.028 or less.

As shown in Examples 4 to 18, high-purity acetonitril having an ultraviolet absorbance of 200 nm or less of 0.05 or less was obtained in a high yield by a simple operation. Industrial applicability

 The crude acetonitrile is brought into contact with nascent oxygen and then passed through a packed column filled with a basic substance and at least one substance selected from the group consisting of a basic substance and an adsorbent to reduce acid and permanganate. Acetonitrile containing less active substances can be produced. This method does not require a cooler, heat source, and advanced temperature control technology compared to the distillation method disclosed in East Germany DD 217 12 12 A1, and is a very simple method for purifying acetonitrile. is there. In addition, crude acetonitrile can be used as a solvent for high-performance liquid chromatography in the production of acetonitrile having an ultraviolet absorbance of 200 to 400 nm having an ultraviolet absorbance of 0.05 or less. Contacting nascent oxygen and then contacting with one or more substances selected from basic substances and / or adsorbents, and subsequently separating or removing low and high boiling compounds, or Contact acetonitrile with nascent oxygen, then separate and remove low-boiling and high-boiling compounds, and then contact with basic substance and one or more selected substances from Z or adsorbent As a result, it is possible to produce acetonitrile having an ultraviolet absorbance of 200 to 400 nm of 0.05 or less.

Claims

The scope of the claims 1. High purity acetonitrile for liquid chromatography-mobile phase solvents, characterized in that the absorbance of ultraviolet rays at a wavelength of 200 to 400 nm is less than 0.05. Lil.  2. When purifying crude acetonitrile,  (1) a first step of contacting raw acetonitrile with nascent oxygen; and  (2) The second step of bringing the acetonitrile that has passed through the first step into contact with one or more substances selected from a basic substance and an adsorbent A method for purifying crude acetonitrile, comprising purifying the crude acetonitrile in the following order.  3. When purifying crude acetonitrile,  (1) a first step of contacting raw acetonitrile with nascent oxygen; and  (2) a second step of bringing the acetonitrile that has passed through the first step into contact with one or more substances selected from a basic substance and an adsorbent;  (3) A third step of separating and removing low-boiling compounds and high-boiling compounds contained in acetonitrile that has passed through the second step, wherein the substance used in the second step is formed from a solid base or an adsorbent. In the case of one selected kind, the third step may be after the first step and before the second step, and the crude step is characterized by purifying the crude acetate. How to purify tonitrile.  4. The raw material crude acetonitrile has an absorbance of ultraviolet light of wavelength 200 nm or more of 0.1, and the obtained acetonitrile has an absorbance of ultraviolet light of wavelength 200 to 400 nm. 4. The method according to claim 3, wherein the method has an acetonitrile of 0.05 or less. 5. The crude acetonitrile of the raw material is converted to a catalyst by catalytic ammoxidation of propylene, isobutene, or tertiary butanol with ammonia and molecular oxygen. 4. The method according to claim 2, wherein the method is acetonitrile obtained as a by-product when producing lonitrile or methacrylonitrile.  6. The compound that generates nascent oxygen used in the first step is selected from permanganic acid or a salt thereof, oxyacid or a salt thereof, peroxide or an ozone-containing gas. 4. The method according to claim 2, wherein the compound is one or more compounds.  7. The method according to claim 6, wherein the peroxide is at least one compound selected from hydrogen peroxide, sodium peroxide, and barium peroxide.  8. Oxygen acid or its salt is sodium hypochlorite, potassium hypochlorite, sodium hypoiodite, potassium hypoiodite, sodium hypobromite, hypoxia. Sodium bromate, sodium chlorate, sodium chlorate, sodium iodate, sodium iodate, sodium bromate, sodium bromate, excess It must be at least one oxyacid or a salt thereof selected from sodium chlorate, potassium perchlorate, perchloric acid, periodate, sodium periodate, and potassium periodate. 7. The method according to claim 6, which is characterized in that:  9. The method according to claims 2 and 3, wherein the contact with the nascent oxygen in the first step is performed in a batch mode or a continuous mode at a temperature of 140 to 80 ° C. Method.  10. The method according to claim 9, wherein the nascent oxygen in the first step is an ozone-containing gas, and is a gas containing 0.01 to 5.0 vol% of ozone.  11. The supply of ozone-containing gas in the batch method requires a gas volume of 1 to 1000 times the volume of crude acetonitrile to be brought into contact with the liquid phase acetonitrile from one or more nozzles. The method according to claim 10, wherein the solution is supplied into the rill for 1 to 300 minutes. 12. It is characterized in that the supply of ozone-containing gas in the batch system is performed until the ozone concentration in the exhaust gas reaches 80% or more of the ozone concentration of the supplied gas. The method of claim 10.  . 13. The gas-liquid contact between the ozone-containing gas and the crude acetonitrile in the continuous process in the first step is performed in a packed tower or a tray column, and the crude acetonitrile is supplied from the top of the tower, The method according to claim 10, wherein the ozone-containing gas is supplied from a bottom of the tower, and the gas Z liquid volume ratio is operated at 1 to 1000.  14. The method according to claim 2, wherein the contact between the acetate and the basic substance and the adsorbent in the second step is performed at a temperature of 140 to 80 ° C. The method of paragraph 3.  15. The basic substance in the second step is at least one compound selected from alkali metal hydroxides, carbonates, bicarbonates, alkaline earth metal hydroxides, ammonia and amines, or 15. The method according to claim 14, wherein the method is an aqueous solution or a solution thereof.  16. The method according to claim 14, wherein the basic substance in the second step is ammonia gas or an ammonia-containing gas.  17. The method according to claim 14, wherein the basic substance in the second step is a solid base.  18. The method according to claim 17, wherein the solid base is an anion exchange resin. 19. In the anion exchange resin porous type or a gel type weakly basic anion ion form is strongly basic anion exchange resin or exchange group is OH-shaped or C 0 ₃ forms is 1-3 primary amino groups 19. The method according to claim 18, wherein the method is an ion exchange resin.  20. When the solid base is an alkali metal hydroxide, an alkali metal carbonate, an alkali metal bicarbonate, an alkaline earth metal oxide, an alkaline earth metal hydroxide, an alkaline earth metal carbonate, 18. The method according to claim 17, wherein the method is at least one compound selected from cammagnesia, calcium silica, strontium silica, and silica oxide. 21. The solid base supports the alkali metal or alkaline earth metal compound on the carrier. 18. The method according to claim 17, wherein the substance is a substance carried.  22. The method according to claim 21, wherein the compound of an alkali metal or an alkaline earth metal is an oxide, a hydroxide, a carbonate or a hydrogen carbonate.  23. The method according to claim 21, wherein the carrier is a substance selected from activated carbon, silica, alumina, titania or zirconia. 24. The solid base is, N ₂ 0, NH ₃ or _{Z n C 1 2 -. NH} , methods ranging first 7 claim of claim, characterized in that activated carbon which is activated with a C 1 one C 0 _2.  25. The adsorbent in the second step is at least one selected from activated carbon, activated alumina, silica gel, synthetic zeolite, natural zeolite, adsorption resin, natural clay mineral, silica alumina, silica magnesia, and silica polya 4. The method according to claims 2 and 3, wherein the method is a compound.  26. The method according to claim 3, wherein the method of separating and removing low-boiling compounds and high-boiling compounds in the third step is at least one method selected from a distillation method and a membrane separation method. The described method.  27. The distillation column in the third step is a plate column or a packed column, and Method c according to claim 26, characterized in that it is operated at a pressure of 0 atm 28. The step of separating and removing low-boiling compounds and high-boiling compounds compared to acetonitrile in the third step consists of two distillation columns, the first column separating and removing low-boiling compounds, and the second column having high-boiling compounds. The method according to claim 26, wherein the compound is separated and removed.  29. The step of separating and removing low-boiling compounds and high-boiling compounds in comparison with acetonitrile in the third step consists of one distillation column. 27. The method according to claim 26, wherein the low-boiling compounds are extracted, the high-boiling compounds are extracted from the bottom, and purified acetonitrile is obtained from above the supply position of the acetonitrile.  30. The method according to claim 3, wherein the process is controlled using near-infrared spectroscopy.