Process and apparatus for the production of high purity acetonitrile from technical acetonitrile

Abstract

The present application relates to the field of chemical reagent refining, and discloses a method and equipment for preparing high-purity acetonitrile from industrial acetonitrile, which comprises the following steps: ozone is subjected to oxidation reaction with industrial acetonitrile under the action of an organic amine supported catalyst and ultraviolet light; after the reaction is completed, the ozone waste gas is directly exhausted after the removal of excess ozone and organic matter by an exhaust column; the acetonitrile after the reaction is completed is subjected to removal of excess impurities by an adsorption column, and high-purity acetonitrile can be collected below the adsorption column; after the adsorption of each equipment is completed, high-purity nitrogen gas is introduced from below the adsorption column, sequentially passes through the adsorption column, the reaction tower and the exhaust column for desorption, and finally enters an absorption tank to remove various impurities desorbed, and the desorption liquid is used for regeneration of the supported catalyst; the desorption liquid after the regeneration is completed enters the absorption tank, and thus the regeneration of each adsorbent and catalyst is completed. The present application has the advantages of low energy consumption, recyclable materials, good equipment stability and no secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of chemical reagent refining, and more specifically to a method and apparatus for preparing high-purity acetonitrile from industrial acetonitrile. Background Technology

[0002] High-purity acetonitrile is an excellent solvent with a wide range of applications. Besides being used as an extractant for alkanes and alkenes, it can also be used in the preparation of fine chemical products such as pharmaceuticals, pesticides, surfactants, and coatings. Higher purity acetonitrile, such as HPLC grade and UP grade, can be used as a mobile phase solvent for high-performance liquid chromatography and as a cleaning solvent for electronic components. High-purity acetonitrile is usually prepared by further purifying lower-purity industrial acetonitrile. Its price can increase more than tenfold after purification, making it highly economical. Compared to industrial acetonitrile, high-purity acetonitrile not only has a lower content of common organic impurities, but also has very strict requirements for other indicators such as ultraviolet transmittance, pH, evaporation residue, and moisture content.

[0003] Currently, the methods used both domestically and internationally to purify industrial acetonitrile to high-purity acetonitrile mainly rely on distillation technology, supplemented by oxidation, adsorption, and physical deweighting techniques. Although these methods are simple and effective, they also have drawbacks such as low yield, high energy consumption, heavy pollution, and low purification quality. If the purification process can be further optimized to overcome the shortcomings of traditional technologies, the economic benefits of producing high-purity acetonitrile from industrial acetonitrile will be greatly improved.

[0004] CN 111413441A discloses an improved acetonitrile purification process for ultra-high performance liquid chromatography-mass spectrometry. This invention obtains a high-purity product through a series of purification unit operations, including oxidation, distillation adsorption, drying, reflux distillation and filtration, and controlling relevant parameters such as temperature and flow rate. However, this process involves many unit operations and is relatively complicated. It also requires the use of several types of filter membrane equipment, resulting in high investment costs.

[0005] CN106674049A discloses a method for preparing chromatographic-grade acetonitrile using industrial-grade acetonitrile. The technical principle involves adding industrial acetonitrile to a chromatography column packed with activated carbon particles for impurity removal, then adding inorganic salts to the effluent to remove water, and finally obtaining chromatographically pure acetonitrile through distillation. However, this method inevitably requires energy-intensive distillation technology, and relying solely on activated carbon and inorganic salts to remove various impurities results in unstable performance.

[0006] CN 112174852A discloses a method for purifying gradient-grade chromatographically pure acetonitrile. The main process involves first subjecting industrial acetonitrile to an oxidation-neutralization reaction, then removing impurities using an adsorption column, and finally obtaining chromatographically pure acetonitrile through distillation. However, this method requires various solid reactants, including multiple solid oxidants, molecular sieves, and activated carbon fibers, none of which can be regenerated. Therefore, a large amount of waste residue is generated after purification, which has an adverse impact on the environment. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of high energy consumption and non-recyclability in the existing technology of purifying industrial acetonitrile to obtain high-purity acetonitrile. This invention provides a method and equipment for preparing high-purity acetonitrile from industrial acetonitrile, which has the advantages of low energy consumption, recyclable materials, and good environmental and economic benefits.

[0008] To achieve the above objectives, the present invention provides a method for preparing high-purity acetonitrile from industrial acetonitrile, the method comprising the following steps;

[0009] Under the catalysis of an organic amine supported catalyst, industrial acetonitrile is contacted with ozone under ultraviolet irradiation to obtain liquid and gaseous products. The liquid product is then subjected to a first adsorption treatment to obtain high-purity acetonitrile.

[0010] A second aspect of the present invention provides an apparatus for purifying industrial acetonitrile to prepare high-purity acetonitrile, the apparatus comprising:

[0011] The reaction unit is equipped with an ultraviolet light emitting device, which is used to bring industrial acetonitrile into contact with ozone and organic amine supported catalysts under ultraviolet irradiation to obtain liquid and gaseous products.

[0012] An adsorption unit connected to the reaction unit is used to perform a first adsorption treatment on the liquid phase product from the reaction unit to obtain high-purity acetonitrile.

[0013] Optionally, the device also includes:

[0014] The exhaust gas treatment unit, which is connected to the reaction unit, is used to purify the gaseous products before releasing them into the atmosphere.

[0015] Compared with existing technologies, the above technical solution provides the following advantages:

[0016] 1. This invention uses industrial acetonitrile as raw material, and utilizes a supported catalyst and ultraviolet light irradiation to react with ozone to remove the main organic impurities. High-purity acetonitrile is then obtained through adsorption. The total yield of acetonitrile is >80%, the mass percentage of the obtained high-purity acetonitrile is ≥99.92%, the moisture content is less than 100 ppm, the content of each individual impurity is less than 50 ppm, and the ultraviolet absorbance at each wavelength meets the specifications for HPLC grade.

[0017] 2. The present invention regenerates the used supported catalyst and adsorbent, which can be recycled for a long time without additional replenishment and with low maintenance costs.

[0018] 3. The method of the present invention does not require the distillation process that is unavoidable in traditional separation methods, so the energy consumption is very low and the economic benefits are very high. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of an equipment for purifying industrial acetonitrile to produce high-purity acetonitrile.

[0020] Figure 2 This is a schematic diagram of the logistics process for purifying industrial acetonitrile to produce high-purity acetonitrile.

[0021] Figure 3 This is a schematic diagram of the desorption gas and eluent flow process in the purification of industrial acetonitrile to produce high-purity acetonitrile.

[0022] Figure 4 yes Figure 1 A schematic diagram of the structure of the reaction tower.

[0023] Explanation of reference numerals in the attached figures

[0024] 1 is the raw material tank, 2 is the reaction tower, 3 is the ozone generator, 4 is the waste removal column, 5 is the adsorption column, and 6 is the desorption tank; A is industrial acetonitrile, B is ozone, C is ozone waste gas, D is acetonitrile after reaction, E is waste gas after adsorption, F is high-purity acetonitrile; G is desorption liquid, H is desorption liquid after regeneration, I, J, and K are desorption gases, and L is desorption gas after impurity removal. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" generally refer to the direction shown in the accompanying drawings or describe the relative positional relationships of components in the vertical, perpendicular, or gravitational direction; "inner" and "outer" refer to the interior and exterior of the cavity relative to the chamber or the radial interior and exterior relative to the center of the circle; in this invention, unless otherwise specified, the "top" of the container refers to the position of the container from top to bottom of 0-10%; the "upper part" of the container refers to the position of the container from top to bottom of 0-33%; the "middle part" of the container refers to the position of the container from top to bottom of 33-66%; the "bottom" of the container refers to the position of the container from bottom to top of 0-10%; and the "lower part" of the container refers to the position of the container from bottom to top of 0-33%.

[0028] This invention provides a method for preparing high-purity acetonitrile from industrial acetonitrile, the method comprising the following steps;

[0029] Under the catalytic action of an organic amine supported catalyst, industrial acetonitrile is contacted with ozone by ultraviolet irradiation to remove trace impurities such as aldehydes, acrylonitrile, and hydrogen cyanide from industrial acetonitrile, resulting in liquid and gaseous products. The liquid product is then subjected to a first adsorption treatment to obtain high-purity acetonitrile.

[0030] This invention uses industrial acetonitrile as raw material, and utilizes a supported catalyst to react with ozone to remove the main organic impurities. The resulting high-purity acetonitrile is then purified using an adsorbent. The total yield of acetonitrile is >80%, the mass percentage of the obtained high-purity acetonitrile is ≥99.92%, the moisture content is less than 100 ppm, the content of each individual impurity is less than 50 ppm, and the ultraviolet absorbance at each wavelength meets the specifications for HPLC grade.

[0031] According to one preferred embodiment of the present invention, the ratio of industrial acetonitrile to ozone is 50:1 to 200:1, preferably 70:1 to 120:1, calculated according to the flow rate.

[0032] According to one preferred embodiment of the present invention, the ratio of the industrial acetonitrile to the organic amine supported catalyst is 20:1 to 50:1, preferably 30:1 to 40:1.

[0033] According to one preferred embodiment of the present invention, the wavelength of the ultraviolet light is 200-365nm, preferably 254nm-315nm; the power of the ultraviolet light source is 10-60W, preferably 20-40W.

[0034] According to one preferred embodiment of the present invention, the method further includes:

[0035] The gaseous products are purified to remove excess ozone and reaction products before being released into the atmosphere. The purification process includes using a second adsorbent to perform a second adsorption on the gaseous products. The conditions for the second adsorption include an adsorption pressure of 150–300 kPa and an adsorption temperature of 5–20 °C.

[0036] According to one preferred embodiment of the present invention, the organic amine supported catalyst is regenerated after contact, the regeneration process comprising: soaking the contacted organic amine supported catalyst in a desorption solution for regeneration; preferably, the mass concentration of the desorption solution is 1-10 wt%.

[0037] The present invention regenerates the used supported catalyst, which can be recycled for a long time without additional replenishment and has low maintenance costs.

[0038] In this invention, the desorption solution is selected from at least one of sodium thiosulfate aqueous solution, sodium bicarbonate aqueous solution, sodium carbonate aqueous solution, or sodium hydroxide aqueous solution.

[0039] In this invention, the particle size of the second adsorbent is 4 to 8 mesh.

[0040] In this invention, preferably, the second adsorbent is selected from at least one of potassium iodide, sodium thiosulfate, methylcellulose, or carboxymethylcellulose.

[0041] According to one preferred embodiment of the present invention, the method for preparing the organic amine supported catalyst includes:

[0042] The organic amine was mixed with a silane coupling agent and added to a first organic solvent. The mixture was heated and stirred, and then a solid phase was added while continuing to heat and stir. After cooling, filtering and drying, the organic amine solid catalyst was obtained.

[0043] According to a preferred embodiment of the present invention, the preparation conditions include: a temperature of 60–120°C, a reaction time of 1–2 h before the addition of the solid phase, and a reaction time of 2–4 h after the addition of the solid phase.

[0044] According to a preferred embodiment of the present invention, the mass ratio of the organic amine to the silane coupling agent is preferably between 1:6 and 12, more preferably between 1:8 and 10.

[0045] In this invention, preferably, the silane coupling agent is selected from tert-butyltrimethylsiloxane and / or tert-butyltrimethylchlorosilane.

[0046] In this invention, preferably, the mass ratio of the organic amine to the first organic solvent is between 1:100 and 400, more preferably between 1:200 and 300.

[0047] In this invention, preferably, the first organic solvent is selected from at least one of ionic liquid, isopropanol, benzene, or methanol.

[0048] In this invention, it is more preferable to use imidazole ionic liquids and / or quaternary ammonium ionic liquids.

[0049] In this invention, the first organic solvent is further preferably selected from 1-ethyl-3-methylimidazolium acetate or 1-ethyl-3-methylimidazolium tetrafluoroborate.

[0050] In this invention, preferably, the mass ratio of the organic amine to the solid support phase is 1:5 to 10.

[0051] In this invention, the organic amine is selected from at least one of dimethylamine, trimethylamine, ethylenediamine, or hexylamine.

[0052] In this invention, the solidified phase is selected from one or more of silica, alumina, MCM-41 molecular sieve and MCM-48 molecular sieve.

[0053] According to one preferred embodiment of the present invention, the liquid phase product is subjected to the first adsorption treatment using a first adsorbent, and the conditions of the first adsorption treatment include: an adsorption pressure of 150-300 kPa and an adsorption temperature of 5-20°C.

[0054] In this invention, preferably, the first adsorbent is pretreated, which includes: impregnating, removing impurities, washing, drying, depositing silicon, baking and activating the first adsorbent in sequence, and then purging.

[0055] In this invention, more preferably, the first adsorbent is impregnated with ethanol and / or ethylene glycol.

[0056] In this invention, an acid with a mass concentration of 3-10% is used for impurity removal.

[0057] In this invention, it is further preferred that the acid is selected from dilute hydrochloric acid or dilute nitric acid.

[0058] In this invention, ultrapure water is used for washing; more preferably, the ultrapure water is of grade one.

[0059] In this invention, the drying temperature is 140–180°C, and the drying time is 2–6 hours.

[0060] In this invention, to further improve the activity of the adsorbent, the silicon deposition process includes placing the first adsorbent in a first organic solvent and heating it until the first organic solvent is completely evaporated.

[0061] It should be noted that the silicon deposition process in this invention uses water bath, steam or oil bath heating, and the heating temperature is 90-110℃.

[0062] In this invention, a second organic solvent containing 5-20% by mass of a silicon modifier is preferably used to perform silicon deposition treatment on the first adsorbent.

[0063] In this invention, the silicon modifier is at least one of methyl orthosilicate, silicon tetrachloride, or silicone oil.

[0064] In this invention, the second organic solvent is at least one of 3-methylpentane, 2-dimethylbutane, or benzene.

[0065] In this invention, the baking temperature is 400-500℃ and the baking time is 3-5 hours.

[0066] In this invention, high-purity nitrogen gas is used for purging.

[0067] In this invention, the reagents used in the pretreatment are at least AR grade.

[0068] According to one preferred embodiment of the present invention, a desorption gas is used to desorb the first and second adsorbents after adsorption; preferably, the desorption pressure is 20-60 kPa and the desorption temperature is 70-100°C.

[0069] The adsorbent in this invention is regenerated after use, allowing for long-term recycling without additional replenishment and resulting in low maintenance costs.

[0070] In this invention, the desorption gas is preferably selected from at least one of high-purity nitrogen, high-purity argon, high-purity carbon dioxide, or high-purity helium. High purity in this invention refers to a purity ≥ 99.99%. High-purity nitrogen is used as an example in the embodiments to illustrate the advantages of this invention, but the invention is not limited thereto.

[0071] In this invention, the particle size of the first adsorbent is 4 to 8 mesh.

[0072] In this invention, the first adsorbent is preferably selected from one or more of 3A molecular sieve, 5A molecular sieve, 13X molecular sieve, polyacrylamide, and carbon molecular sieve.

[0073] In this invention, the composition of the industrial acetonitrile, by mass fraction, is: acetonitrile ≥ 99.5%, moisture ≤ 0.35%, propionitrile ≤ 1000 ppm, acrylonitrile ≤ 200 ppm, hydrogen cyanide ≤ 100 ppm, and other single organic impurities ≤ 50 ppm.

[0074] In this invention, the contact time between the industrial acetonitrile and the ozone is 10 to 30 minutes.

[0075] This invention provides an apparatus for purifying industrial acetonitrile to prepare high-purity acetonitrile, the apparatus comprising:

[0076] The reaction unit is equipped with an ultraviolet light emitting device, which is used to contact industrial acetonitrile with ozone and organic amine supported catalyst under ultraviolet light irradiation to obtain liquid phase products and gas phase products.

[0077] An adsorption unit connected to the reaction unit is used to perform a first adsorption treatment on the liquid phase product from the reaction unit to obtain high-purity acetonitrile.

[0078] Optionally, the device also includes:

[0079] The exhaust gas treatment unit, which is connected to the reaction unit, is used to purify the gaseous products before releasing them into the atmosphere.

[0080] This invention uses industrial acetonitrile as raw material and utilizes a supported catalyst to react with ozone under ultraviolet light to remove the main organic impurities. The acetonitrile is then purified using an adsorbent to obtain high-purity acetonitrile. The total yield of acetonitrile is >80%, the mass percentage of the obtained high-purity acetonitrile is ≥99.92%, the moisture content is less than 100 ppm, the content of each individual impurity is less than 50 ppm, and the ultraviolet absorbance at various wavelengths meets the specifications for HPLC. This method eliminates the need for the distillation process unavoidable in traditional separation methods, thus resulting in very low energy consumption and high economic benefits.

[0081] In this invention, the reaction unit includes a reaction tower 2, which is equipped with an ultraviolet light emitting device; the adsorption unit includes an adsorption column 5; and the exhaust gas treatment unit includes a waste removal column 4. The waste removal column 4, the reaction tower 2, and the adsorption column 5 are connected in series.

[0082] In this invention, the reaction tower 2 has a first feed inlet at its top and an ozone feed inlet at its bottom, allowing industrial acetonitrile fed through the first feed inlet and ozone fed through the ozone feed inlet to come into countercurrent contact inside the reaction tower. The first feed inlet is connected to a raw material tank 1 storing industrial acetonitrile, and the ozone feed inlet is connected to an ozone generator 3.

[0083] In this invention, preferably, the main body of the reaction tower 2 is a cylindrical structure with an internal cavity height of 500-1000mm and a diameter of 300-600mm, and is equipped with a stirring paddle. The fixed end of the stirring paddle is fixed in the internal cavity by a bracket connected to the inner wall of the reaction tower.

[0084] In this invention, an ultraviolet light emitting device is fixed to the top of the interior of the reaction tower 2 by a bracket.

[0085] In this invention, the number of light sources in the ultraviolet light emitting device is 1 to 2.

[0086] In this invention, the top of the interior of the reaction tower 2 is provided with a liquid distribution structure for uniformly dispersing industrial acetonitrile.

[0087] In this invention, a gas distribution structure for dispersing ozone is provided at the bottom of the interior of the reaction tower 2.

[0088] In this invention, more preferably, the liquid distribution structure is connected to the sprayer of the first feed inlet.

[0089] In this invention, the gas distribution structure is a porous membrane.

[0090] In this way, industrial acetonitrile enters the reaction tower from the top and is evenly dispersed by a sprayer and poured from top to bottom; ozone enters the reaction tower from the bottom through the pore membrane and comes into contact with the industrial acetonitrile and the solid-phase catalyst under ultraviolet light from bottom to top.

[0091] In this invention, the interior of the reaction tower 2 is provided with a catalyst box for fixing the catalyst, and the catalyst box is capable of passing through the gas phase and the liquid phase.

[0092] In this invention, the reaction tower 2 is provided with a second feed inlet for soaking and regenerating the organic amine supported catalyst with feed desorption liquid; specifically, a stirring paddle can be used for stirring during the soaking and regeneration process, and the second feed inlet is connected to a sprayer.

[0093] In this invention, the reaction tower may optionally be connected to a desorption tank for introducing the soaked and regenerated desorption solution into the desorption tank.

[0094] In this invention, the upper part of the adsorption column 5 is connected to the lower part of the reaction tower 2, and the lower part of the adsorption column 5 is provided with a high-purity acetonitrile outlet and a desorption gas inlet; more preferably, the desorption tank 6 is connected to the waste removal column, and is used to introduce desorption gas into the desorption tank 6. In this way, desorption gas (e.g., high-purity nitrogen) is introduced from below the adsorption column, passes sequentially through the adsorption column, the reaction tower, the waste removal column, and finally enters the desorption tank above the waste removal column.

[0095] The method and apparatus of the present invention are further described below with reference to embodiments, but the present invention is not limited thereto.

[0096] The following examples are in Figures 1-4 The process is carried out in the equipment shown, which includes: a reaction unit, an adsorption unit, and a tail gas treatment unit; wherein, the reaction unit includes a reaction tower 2, the adsorption unit includes an adsorption column 5, and the tail gas treatment unit includes a waste removal column 4; the waste removal column 4, the reaction tower 2, and the adsorption column 5 are connected in series in sequence.

[0097] The top of the reaction tower 2 is provided with a first feed inlet, which is connected to a sprayer. The bottom is provided with an ozone feed inlet and a porous membrane for dispersing ozone. An agitator is provided inside the reaction tower 2, which is connected to the inner wall of the reaction tower by a support. An ultraviolet light emitting device is fixed inside the reaction tower 2 by a support. The reaction tower 2 is provided with a catalyst box that allows gas and liquid phases to pass through but not the catalyst. The reaction tower is connected to the desorption tank 6, and the reaction tower 2 is provided with a second feed inlet connected to the sprayer. The lower part of the reaction tower 2 is connected to the upper part of the adsorption column 5. The lower part of the adsorption column 5 is provided with a high-purity acetonitrile outlet and a desorption gas inlet. The desorption tank 6 is connected to the waste removal column 4.

[0098] The method performed in the above-mentioned equipment includes: under the catalysis of an organic amine supported catalyst, industrial acetonitrile and ozone are reacted with ozone under ultraviolet light to obtain liquid and gaseous products. The liquid product is subjected to a first adsorption treatment to obtain high-purity acetonitrile. The gaseous product is then discharged into the atmosphere after a second adsorption using a second adsorbent. The organic amine supported catalyst is regenerated by soaking it with a desorption liquid. High-purity nitrogen is introduced into the desorption gas inlet to desorb the adsorption column, reaction tower and waste removal column. The desorbed gas is then introduced into the desorption tank. The desorption liquid is also introduced into the absorption tank after regeneration.

[0099] The preparation method of organic amine supported catalyst includes: mixing organic amine with silane coupling agent and adding it to organic solvent, heating and stirring, then adding the supported phase and continuing to heat and stir, cooling, filtering and drying to obtain organic amine supported catalyst, and the prepared supported catalyst is pre-loaded into the reaction tower.

[0100] The liquid phase product is subjected to a first adsorption treatment using a first adsorbent. The first adsorbent is pretreated, which includes: impregnation, impurity removal, washing, drying, silicon deposition, baking activation, and purging. The pretreated first adsorbent is then placed in an adsorption column.

[0101] The analytical methods for each technical indicator of this invention using chromatographically pure acetonitrile are based on the normative documents referenced in Q / SHAQ 02.28-2002 and SH / T1627.1-2014.

[0102] GB / T 6283-2008 Determination of moisture content in chemical products - Karl Fischer method (general method);

[0103] GB / T 9740-2008 General Method for Determination of Evaporation Residue of Chemical Reagents;

[0104] GB / T 611-2021 General Method for Determination of Density of Chemical Reagents;

[0105] GB / T 9736-2008 General methods for the determination of acidity and alkalinity of chemical reagents;

[0106] GB / T 9721-2006 General Rules for Molecular Absorption Spectrophotometry of Chemical Reagents (Ultraviolet and Visible Parts);

[0107] GB / T 9722-2006 General Rules for Gas Chromatography of Chemical Reagents

[0108]

Example 1

[0109] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 600 ppm, acrylonitrile 150 ppm, hydrogen cyanide 60 ppm, and other single organic impurities not exceeding 40 ppm.

[0110] The organic amine supported catalyst was prepared by mixing tert-butyltrimethylchlorosilane and hexylamine at a mass ratio of 8:1 and adding it to 1-ethyl-3-methylimidazolium tetrafluoroborate. The mass ratio of 1-ethyl-3-methylimidazolium tetrafluoroborate to hexylamine was 250:1. After maintaining the temperature at 80℃ and stirring for 1.5 h, alumina was added and the mixture was heated and stirred for another 3 h. The solution was cooled, filtered, and dried to obtain the organic amine supported catalyst, wherein the ratio of organic amine to the supported phase was 1:6.

[0111] After the organic amine supported catalyst was prepared, the first adsorbent was pretreated. The first adsorbent was a mixture of 5A molecular sieve and carbon molecular sieve with a particle size of 6 mesh. It was soaked in ethanol, then purified with 5% dilute nitric acid, washed with first-stage ultrapure water, and dried in an oven at 160℃ for 4 hours. After cooling, it was placed in a benzene solution containing 15% silicon tetrachloride by mass, and silicon deposition was performed by heating in a water bath at 100℃. After the solution was completely evaporated, it was activated in a muffle furnace at 450℃ for 4 hours. Then, the organic amine supported catalyst was placed in the catalyst box of the reaction tower, and the adsorbent was placed in the adsorption column.

[0112] Industrial acetonitrile is fed into the reaction tower from the raw material tank, and then sprayed from top to bottom through a sprayer. Ozone generated by an ozone generator enters from the bottom of the reaction tower and reacts with the industrial acetonitrile under the action of an organic amine supported catalyst. The agitator inside the reaction tower is activated to enhance the mass transfer process between the two. The ratio of industrial acetonitrile to ozone is 100:1, and the ratio of industrial acetonitrile to organic amine supported catalyst is 35:1. The wavelength of the ultraviolet light source is 254nm, the power is 30W, and the residence time of industrial acetonitrile in the tower is 15min. After the reaction, the ozone exhaust gas enters the waste removal column, where impurities are removed by the second adsorbent in the waste removal column before being directly discharged into the atmosphere. The second adsorbent in the waste removal column is sodium thiosulfate with a particle size of 5 mesh, an adsorption pressure of 220kPa, and an adsorption temperature of 15℃. Acetonitrile enters the adsorption column to remove excess impurities, and high-purity acetonitrile can be collected at the bottom of the adsorption column, where the adsorption pressure is 200kPa and the adsorption temperature is 10℃. After the reaction is complete, 5% sodium carbonate is used as the desorption solution, which enters the reaction tower from the top and soaks the organic amine supported catalyst to regenerate it. After regeneration, the desorption solution enters the absorption tank. Then, high-purity nitrogen enters from the bottom of the adsorption column and purges and desorbs the adsorption column, the reaction tower, and the waste removal column in sequence. Finally, it enters the desorption tank to absorb impurities and is then discharged. The entire desorption process maintains a desorption pressure of 40 kPa and a desorption temperature of 75°C.

[0113]

Example 2

[0114] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 780 ppm, acrylonitrile 120 ppm, hydrogen cyanide 80 ppm, and other single organic impurities not exceeding 30 ppm.

[0115] The organic amine supported catalyst was prepared by mixing tert-butyltrimethylchlorosilane and dimethylamine at a mass ratio of 10:1 and adding it to 1-ethyl-3-methylimidazolium acetate at a mass ratio of 220:1. After stirring at 90℃ for 2 hours, MCM-41 molecular sieve was added and the mixture was heated and stirred for another 4 hours. The solution was cooled, filtered, and dried to obtain the organic amine supported catalyst, wherein the ratio of organic amine to the supported phase was 1:5.

[0116] After the organic amine-supported catalyst was prepared, the first adsorbent was pretreated. The first adsorbent was a mixture of 3A molecular sieve and polyacrylamide with a particle size of 4 mesh. It was soaked in ethylene glycol, then purified with 8% dilute hydrochloric acid, washed with first-grade ultrapure water, and dried in an oven at 170℃ for 5 hours. After cooling, it was placed in a 2-dimethylbutane solution containing 17% silicone oil by mass, and silicon deposition was performed by heating in an oil bath at 110℃. After the solution was completely evaporated, it was activated in a muffle furnace at 500℃ for 5 hours. Then, the organic amine-supported catalyst was placed in the catalyst box of the reaction tower, and the adsorbent was placed in the adsorption column.

[0117] Industrial acetonitrile is fed into the reaction tower from the raw material tank, and then sprayed from top to bottom through a sprayer. Ozone generated by an ozone generator enters from the bottom of the reaction tower and reacts with the industrial acetonitrile under the action of a supported catalyst. The agitator inside the reaction tower is activated to enhance the mass transfer process between the two. The ratio of industrial acetonitrile to ozone is 80:1, and the ratio of industrial acetonitrile to organic amine supported catalyst is 30:1. The wavelength of the ultraviolet light source is 254nm, the power is 40W, and the residence time of industrial acetonitrile in the tower is 25min. After the reaction, the ozone exhaust gas enters the waste removal column, where impurities are removed by the second adsorbent in the waste removal column before being directly discharged into the atmosphere. The second adsorbent is sodium thiosulfate and methylcellulose, with a particle size of 4 mesh, an adsorption pressure of 280kPa, and an adsorption temperature of 10℃. Acetonitrile enters the adsorption column to remove excess impurities, and high-purity acetonitrile can be collected at the bottom of the adsorption column, with an adsorption pressure of 260kPa and an adsorption temperature of 8℃. After the reaction is complete, an 8% sodium thiosulfate solution is used as the desorption liquid, which enters the reaction tower from above and soaks the organic amine supported catalyst to regenerate it. After regeneration, the desorption liquid enters the absorption tank. Then, high-purity nitrogen gas enters from below the adsorption column and purges and desorbs the adsorption column, the reaction tower, and the waste removal column in sequence. Finally, the gas enters the desorption tank to absorb impurities and is then discharged. The entire desorption process maintains a desorption pressure of 50 kPa and a desorption temperature of 85°C.

[0118]

Example 3

[0119] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 500 ppm, acrylonitrile 180 ppm, hydrogen cyanide 40 ppm, and other single organic impurities not exceeding 45 ppm.

[0120] The organic amine supported catalyst was prepared by mixing tert-butyltrimethylchlorosilane and trimethylamine at a mass ratio of 12:1 and adding it to 1-ethyl-3-methylimidazolium tetrafluoroborate. The mass ratio of 1-ethyl-3-methylimidazolium tetrafluoroborate to trimethylamine was 350:1. After stirring at 65°C for 1 hour, silica was added and the mixture was heated and stirred for another 2.5 hours. The solution was cooled, filtered, and dried to obtain the organic amine supported catalyst, wherein the ratio of organic amine to the supported phase was 1:9.

[0121] After the organic amine-supported catalyst was prepared, the first adsorbent was pretreated. The first adsorbent used was a 13X molecular sieve with a particle size of 7 mesh. It was soaked in ethanol, then purified with 3% dilute nitric acid, washed with first-stage ultrapure water, and dried in an oven at 140℃ for 3 hours. After cooling, it was placed in a 3-methylpentane solution containing 8% (w / w) methyl orthosilicate, and silicon deposition was performed by heating in an oil bath at 95℃. After the solution was completely evaporated, it was activated in a muffle furnace at 400℃ for 3 hours. Then, the organic amine-supported catalyst was placed in the catalyst box of the reaction tower, and the adsorbent was placed in the adsorption column.

[0122] Industrial acetonitrile is fed into the reaction tower from the raw material tank, and then sprayed from top to bottom through a sprayer. Ozone generated by an ozone generator enters from the bottom of the reaction tower and reacts with the industrial acetonitrile under the action of an organic amine supported catalyst. The agitator inside the reaction tower is activated to enhance the mass transfer process between the two. The ratio of industrial acetonitrile to ozone is 150:1, and the ratio of industrial acetonitrile to organic amine supported catalyst is 46:1. The wavelength of the ultraviolet light source is 335nm, the power is 50W, and the residence time of industrial acetonitrile in the tower is 12min. After the reaction, the ozone exhaust gas enters the waste removal column, where impurities are removed by the second adsorbent in the waste removal column before being directly discharged into the atmosphere. The second adsorbent in the waste removal column is potassium iodide with a particle size of 7 mesh, an adsorption pressure of 170kPa, and an adsorption temperature of 18℃. Acetonitrile enters the adsorption column to remove excess impurities, and high-purity acetonitrile can be collected at the bottom of the adsorption column, where the adsorption pressure is 180kPa and the adsorption temperature is 20℃. After the reaction is complete, a 4% sodium bicarbonate solution is used as the desorption liquid, which enters the reaction tower from above and soaks the organic amine supported catalyst to regenerate it. After regeneration, the desorption liquid enters the absorption tank. Then, high-purity nitrogen gas enters from below the adsorption column and purges and desorbs the adsorption column, the reaction tower, and the waste removal column in sequence. Finally, the gas enters the desorption tank to absorb impurities and is then discharged. The entire desorption process maintains a desorption pressure of 60 kPa and a desorption temperature of 72 °C.

[0123]

Example 4

[0124] Adopting such Figure 1The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 720 ppm, acrylonitrile 140 ppm, hydrogen cyanide 65 ppm, and other single organic impurities not exceeding 30 ppm.

[0125] The organic amine-supported catalyst was prepared by mixing tert-butyltrimethylsiloxane and ethylenediamine at a mass ratio of 8.5:1 and adding it to 1-ethyl-3-methylimidazolium tetrafluoroborate at a mass ratio of 240:1. The reaction was carried out at 90℃ with stirring for 1.2 h. Then, MCM-48 molecular sieve was added and the mixture was heated and stirred for another 3.2 h. After cooling, filtering and drying, the organic amine-supported catalyst was obtained, with the ratio of organic amine to supported phase being 1:7.

[0126] After the organic amine supported catalyst was prepared, the first adsorbent was pretreated. The first adsorbent was a mixture of 13X molecular sieve and polyacrylamide with a particle size of 5 mesh. It was soaked in ethylene glycol, then purified with 5% dilute hydrochloric acid, washed with first-stage ultrapure water, and dried in an oven at 165℃ for 4.5 h. After cooling, it was placed in a 2-dimethylbutane solution containing 12% silicon tetrachloride by mass, and silicon deposition was performed by heating in an oil bath at 105℃. After the solution was completely evaporated, it was activated in a muffle furnace at 420℃ for 4 h. Then, the supported catalyst was placed in the catalyst box of the reaction tower, and the adsorbent was placed in the adsorption column.

[0127] Industrial acetonitrile is fed into the reaction tower from the raw material tank and then sprayed from top to bottom through a sprayer. Ozone generated by an ozone generator enters from the bottom of the reaction tower and reacts with the industrial acetonitrile under the action of an organic amine supported catalyst. The agitator inside the reaction tower is activated to enhance the mass transfer process between the two. The ratio of industrial acetonitrile to ozone is 80:1, and the ratio of industrial acetonitrile to organic amine supported catalyst is 32:1. The wavelength of the ultraviolet light source is 290nm, the power is 35W, and the residence time of industrial acetonitrile in the tower is 18min. After the reaction, the ozone exhaust gas enters the waste removal column, where impurities are removed by the second adsorbent in the waste removal column before being directly discharged into the atmosphere. The second adsorbent in the waste removal column is potassium iodide and carboxymethyl cellulose, with a particle size of 5 mesh, an adsorption pressure of 260kPa, and an adsorption temperature of 13℃. Acetonitrile enters the adsorption column to remove excess impurities, and high-purity acetonitrile can be collected at the bottom of the adsorption column, where the adsorption pressure is 220kPa and the adsorption temperature is 8℃. After the reaction is complete, a 6% sodium hydroxide solution is used as the desorption liquid, which enters the reaction tower from above and soaks the organic amine supported catalyst to regenerate it. After regeneration, the desorption liquid enters the absorption tank. Then, high-purity nitrogen gas enters from below the adsorption column and purges and desorbs the adsorption column, the reaction tower, and the waste removal column in sequence. Finally, the gas enters the desorption tank to absorb impurities and is then discharged. The entire desorption process maintains a desorption pressure of 35 kPa and a desorption temperature of 85 °C.

[0128]

Example 5

[0129] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 380 ppm, acrylonitrile 90 ppm, hydrogen cyanide 70 ppm, and other single organic impurities not exceeding 40 ppm.

[0130] The organic amine-supported catalyst was prepared by mixing tert-butyltrimethylsiloxane and trimethylamine at a mass ratio of 10:1 and adding it to 1-ethyl-3-methylimidazolium acetate at a mass ratio of 210:1. The reaction was carried out at 75°C with stirring for 1.5 h, followed by the addition of alumina and continued heating and stirring for 2.8 h. The solution was cooled, filtered, and dried to obtain the organic amine-supported catalyst, wherein the ratio of organic amine to the supported phase was 1:6.

[0131] After the organic amine-supported catalyst was prepared, the first adsorbent was pretreated. The first adsorbent was a mixture of 13X molecular sieve, polyacrylamide, and carbon molecular sieve with a particle size of 7 mesh. It was soaked in ethanol, then purified with 6% dilute nitric acid, washed with first-stage ultrapure water, and dried in an oven at 150℃ for 4 hours. After cooling, it was placed in a benzene solution containing 16% methyl orthosilicate and silicon was deposited by heating in a 98℃ water bath. After the solution was completely evaporated, it was activated in a muffle furnace at 480℃ for 3.5 hours. Then, the organic amine-supported catalyst was placed in the catalyst box of the reaction tower, and the adsorbent was placed in the adsorption column.

[0132] Industrial acetonitrile is fed into the reaction tower from the raw material tank and then sprayed from top to bottom through a sprayer. Ozone generated by an ozone generator enters from the bottom of the reaction tower and reacts with the industrial acetonitrile under the action of an organic amine supported catalyst. The agitator inside the reaction tower is activated to enhance the mass transfer process between the two. The ratio of industrial acetonitrile to ozone is 85:1, and the ratio of industrial acetonitrile to organic amine supported catalyst is 34:1. The wavelength of the ultraviolet light source is 290nm, the power is 40W, and the residence time of industrial acetonitrile in the tower is 14min. After the reaction, the ozone exhaust gas enters the waste removal column, where impurities are removed by the second adsorbent in the waste removal column before being directly discharged into the atmosphere. The second adsorbent in the waste removal column is sodium thiosulfate and carboxymethyl cellulose, with a particle size of 4 mesh, an adsorption pressure of 160kPa, and an adsorption temperature of 10℃. Acetonitrile enters the adsorption column to remove excess impurities, and high-purity acetonitrile can be collected at the bottom of the adsorption column, where the adsorption pressure is 240kPa and the adsorption temperature is 15℃. After the reaction is complete, a 7% sodium thiosulfate solution is used as the desorption liquid, which enters the reaction tower from above and soaks the organic amine supported catalyst to regenerate it. After regeneration, the desorption liquid enters the absorption tank. Then, high-purity nitrogen gas enters from below the adsorption column and purges and desorbs the adsorption column, the reaction tower, and the waste removal column in sequence. Finally, the gas enters the desorption tank to absorb impurities and is then discharged. The entire desorption process maintains a desorption pressure of 60 kPa and a desorption temperature of 90 °C.

[0133]

Example 6

[0134] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 830 ppm, acrylonitrile 220 ppm, hydrogen cyanide 80 ppm, and other single organic impurities not exceeding 50 ppm.

[0135] The organic amine-supported catalyst was prepared by mixing tert-butyltrimethylchlorosilane and dimethylamine at a mass ratio of 8.2:1, and then adding it to 1-ethyl-3-methylimidazolium tetrafluoroborate (1-ethyl-3-methylimidazolium tetrafluoroborate to dimethylamine mass ratio 260:1). The reaction was carried out at 80℃ with stirring for 2.5 h. Silica was then added, and the mixture was heated and stirred for another 4 h. The solution was cooled, filtered, and dried to obtain the organic amine-supported catalyst, with an organic amine to supported phase ratio of 1:9. The supported catalyst was then placed in the catalyst box of the reaction tower, and an adsorbent with a particle size of 6 mesh, composed of polyacrylamide and carbon molecular sieve, was directly placed in the adsorption column.

[0136] Industrial acetonitrile is fed into the reaction tower from the raw material tank and then sprayed from top to bottom through a sprayer. Ozone generated by an ozone generator enters from the bottom of the reaction tower and reacts with the industrial acetonitrile under the action of an organic amine supported catalyst. The agitator inside the reaction tower is activated to enhance the mass transfer process between the two. The ratio of industrial acetonitrile to ozone is 100:1, and the ratio of industrial acetonitrile to organic amine supported catalyst is 34:1. The wavelength of the ultraviolet light source is 290nm, the power is 40W, and the residence time of industrial acetonitrile in the tower is 25min. After the reaction, the ozone exhaust gas enters the waste removal column, where impurities are removed by the second adsorbent in the waste removal column before being directly discharged into the atmosphere. The second adsorbent in the waste removal column consists of potassium iodide and methylcellulose, with a particle size of 5 mesh, an adsorption pressure of 260kPa, and an adsorption temperature of 12℃. Acetonitrile enters the adsorption column to remove excess impurities, and high-purity acetonitrile can be collected at the bottom of the adsorption column, where the adsorption pressure is 190kPa and the adsorption temperature is 10℃. After the reaction is complete, a 5% sodium hydroxide solution is used as the desorption liquid, which enters the reaction tower from above and soaks the organic amine supported catalyst to regenerate it. After regeneration, the desorption liquid enters the absorption tank. Then, high-purity nitrogen gas enters from below the adsorption column and purges and desorbs the adsorption column, the reaction tower, and the waste removal column in sequence. Finally, the gas enters the desorption tank to absorb impurities and is then discharged. The entire desorption process maintains a desorption pressure of 50 kPa and a desorption temperature of 95℃.

[0137] Comparative Example 1

[0138] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 480 ppm, acrylonitrile 120 ppm, hydrogen cyanide 80 ppm, and other single organic impurities not exceeding 40 ppm.

[0139] The organic amine-supported catalyst was prepared by mixing tert-butyltrimethylchlorosilane and hexylamine at a mass ratio of 9.2:1, and then adding the mixture to 1-ethyl-3-methylimidazolium tetrafluoroborate (1-ethyl-3-methylimidazolium tetrafluoroborate to hexylamine mass ratio 270:1). The reaction was carried out at 65℃ with stirring for 3 hours. Alumina was then added, and the mixture was heated and stirred for another 2 hours. The solution was cooled, filtered, and dried to obtain the organic amine-supported catalyst, with an organic amine to supported phase ratio of 1:6. The supported catalyst was then placed in the catalyst box of the reaction tower.

[0140] Industrial acetonitrile is fed into the reaction tower from the raw material tank and then sprayed from top to bottom through a sprayer. Ozone generated by an ozone generator enters from the bottom of the reaction tower and reacts with the industrial acetonitrile under the action of an organic amine supported catalyst. The agitator inside the reaction tower is activated to enhance the mass transfer process between the two. The ratio of industrial acetonitrile to ozone is 110:1, and the ratio of industrial acetonitrile to organic amine supported catalyst is 37:1. The wavelength of the ultraviolet light source is 290 nm, the power is 40 W, and the residence time of industrial acetonitrile in the tower is 22 min. After the reaction, the ozone exhaust gas enters the waste removal column, where impurities are removed by the second adsorbent in the waste removal column before being directly discharged into the atmosphere. The second adsorbent in the waste removal column is sodium thiosulfate with a particle size of 4 mesh, an adsorption pressure of 240 kPa, and an adsorption temperature of 15 °C. Acetonitrile is collected directly after the reaction. After the reaction is complete, an 8% sodium bicarbonate solution is used as the desorption liquid, which enters the reaction tower from above and soaks the organic amine supported catalyst to regenerate it. After regeneration, the desorption liquid enters the absorption tank. Then, high-purity nitrogen enters from below the adsorption column and purges and desorbs the adsorption column, the reaction tower, and the waste removal column in sequence. Finally, it enters the desorption tank to absorb impurities and is then discharged. The entire desorption process maintains a desorption pressure of 50 kPa and a desorption temperature of 90 °C.

[0141] Comparative Example 2

[0142] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 650 ppm, acrylonitrile 80 ppm, hydrogen cyanide 90 ppm, and other single organic impurities not exceeding 50 ppm.

[0143] The first adsorbent was pretreated using a mixture of 3A and 5A molecular sieves with a particle size of 6 mesh. It was soaked in ethylene glycol, then purified with 3% dilute hydrochloric acid, washed with first-grade ultrapure water, and dried in an oven at 150°C for 3 hours. After cooling, it was placed in a 3-methylpentane solution containing 10% silicon tetrachloride and silicon was deposited using an oil bath at 105°C. After the solution was completely evaporated, it was activated in a muffle furnace at 420°C for 4 hours. The adsorbent was then placed in an adsorption column.

[0144] Industrial acetonitrile is fed into the reaction tower from the raw material tank, and then sprayed downwards via a sprayer. Ozone generated by an ozone generator enters from the bottom of the reaction tower and reacts directly with the industrial acetonitrile. The agitator inside the reaction tower is activated to enhance the mass transfer process. The ratio of industrial acetonitrile to ozone is 90:1. The ultraviolet light source has a wavelength of 290 nm and a power of 40 W. The residence time of the industrial acetonitrile in the tower is 14 minutes. After the reaction, the ozone exhaust gas enters the waste removal column, where impurities are removed by the second adsorbent before being directly discharged into the atmosphere. The second adsorbent in the waste removal column consists of sodium thiosulfate and methylcellulose, with a particle size of 5 mesh, an adsorption pressure of 180 kPa, and an adsorption temperature of 12°C. Acetonitrile then enters the adsorption column to remove excess impurities. High-purity acetonitrile is collected at the bottom of the adsorption column, where the adsorption pressure is 210 kPa and the adsorption temperature is 18°C. After the reaction is complete, high-purity nitrogen enters from below the adsorption column and purges and desorbs the adsorption column, reaction tower, and waste removal column in sequence. Finally, it enters the desorption tank to absorb impurities and is then discharged. The entire desorption process maintains a desorption pressure of 40 kPa and a desorption temperature of 75°C.

[0145] Comparative Example 3

[0146] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 560 ppm, acrylonitrile 180 ppm, hydrogen cyanide 60 ppm, and other single organic impurities not exceeding 50 ppm.

[0147] The organic amine-supported catalyst was prepared by mixing tert-butyltrimethylsiloxane and trimethylamine at a mass ratio of 8.6:1 and adding it to 1-ethyl-3-methylimidazolium acetate. The mass ratio of 1-ethyl-3-methylimidazolium tetrafluoroborate to hexylamine was 250:1. After stirring at 100℃ for 1.5 h, MCM-41 molecular sieve was added and the mixture was heated and stirred for another 2 h. The solution was cooled, filtered, and dried to obtain the organic amine-supported catalyst, wherein the ratio of organic amine to the supported phase was 1:5.

[0148] After the organic amine-supported catalyst was prepared, the first adsorbent was pretreated. The first adsorbent was a mixture of 3A molecular sieve and polyacrylamide with a particle size of 4 mesh. It was soaked in ethanol, then purified with 6% dilute nitric acid, washed with first-stage ultrapure water, and dried in an oven at 150℃ for 3 hours. After cooling, it was placed in a 3-methylpentane solution containing 14% silicone oil by mass, and silicon deposition was performed by heating in an oil bath at 105℃. After the solution was completely evaporated, it was activated in a muffle furnace at 400℃ for 3 hours. Then, the organic amine-supported catalyst was placed in the catalyst box of the reaction tower, and the adsorbent was placed in the adsorption column.

[0149] Industrial acetonitrile was fed into the reaction tower from the raw material tank and then sprayed from top to bottom through a sprayer. The ratio of industrial acetonitrile to organic amine supported catalyst was 36:1. The wavelength of the ultraviolet light source was 315 nm, and the power was 25 W. The residence time of industrial acetonitrile in the tower was 25 min. After the reaction, the acetonitrile entered the adsorption column to remove excess impurities. High-purity acetonitrile was collected at the bottom of the adsorption column, with an adsorption pressure of 270 kPa and an adsorption temperature of 5 °C. After the reaction, a 10% (w / w) sodium thiosulfate solution was used as the desorption liquid, which entered the reaction tower from the top and soaked the organic amine supported catalyst for regeneration. After regeneration, the desorption liquid entered the absorption tank. Then, high-purity nitrogen gas entered from the bottom of the adsorption column to purge and desorb the adsorption column, the reaction tower, and the waste removal column in sequence. Finally, the gas entered the desorption tank to absorb impurities before being discharged. The entire desorption process maintained a desorption pressure of 20 kPa and a desorption temperature of 90 °C.

[0150] Comparative Example 4

[0151] Adopting such Figure 1 The process shown uses industrial acetonitrile as a raw material, which, by mass fraction, consists of: acetonitrile 99.5%, water 0.35%, propionitrile 490 ppm, acrylonitrile 240 ppm, hydrogen cyanide 75 ppm, and other single organic impurities not exceeding 50 ppm.

[0152] The organic amine-supported catalyst was prepared by mixing tert-butyltrimethylchlorosilane and hexylamine at a mass ratio of 9.2:1, and then adding it to 1-ethyl-3-methylimidazolium tetrafluoroborate at a mass ratio of 200:1. The reaction was carried out at 85℃ with stirring for 4 hours. Then, MCM-48 molecular sieve was added, and the mixture was heated and stirred for another 1.5 hours. The solution was cooled, filtered, and dried to obtain the organic amine-supported catalyst, with an organic amine to supported phase ratio of 1:8. The supported catalyst was then placed in the catalyst box of the reaction tower.

[0153] After the organic amine supported catalyst was prepared, the first adsorbent was pretreated. The first adsorbent was a mixture of carbon molecular sieve and polyacrylamide with a particle size of 5 mesh. It was soaked in ethylene glycol and then purified with 4% dilute nitric acid. After washing with first-grade ultrapure water, it was dried in an oven at 160℃ for 3 hours. After cooling, it was placed in a 3-methylpentane solution containing 10% methyl orthosilicate by mass. Silicon deposition was carried out by heating in an oil bath at 102℃. After the solution was completely evaporated, it was activated in a muffle furnace at 450℃ for 4 hours. The first adsorbent was then placed in an adsorption column.

[0154] Industrial acetonitrile is fed into the reaction tower from the raw material tank and then sprayed from top to bottom through a sprayer. The ratio of industrial acetonitrile to organic amine supported catalyst is 32:1, and the residence time of industrial acetonitrile in the tower is 30 minutes. After the reaction, the acetonitrile enters the adsorption column to remove excess impurities. High-purity acetonitrile is collected at the bottom of the adsorption column, with an adsorption pressure of 220 kPa and an adsorption temperature of 10°C. After the reaction, an 8% (w / w) sodium thiosulfate solution is used as the desorption liquid, which enters the reaction tower from the top and soaks the organic amine supported catalyst for regeneration. After regeneration, the desorption liquid enters the absorption tank. Then, high-purity nitrogen gas enters from the bottom of the adsorption column and sequentially purges and desorbs the adsorption column, the reaction tower, and the waste removal column. Finally, the gas enters the desorption tank to absorb impurities before being vented. The entire desorption process maintains a desorption pressure of 30 kPa and a desorption temperature of 85°C.

[0155] Performance testing comparison

[0156] Table 1: Report on HPLC-grade acetonitrile detection results of examples

[0157] Table 1

[0158]

[0159]

[0160] Table 2: Comparative Example Acetonitrile Test Results Report

[0161] Table 2

[0162]

[0163] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing high-purity acetonitrile from industrial acetonitrile, characterized in that, The method includes the following steps; Under the catalysis of an organic amine-supported catalyst, industrial acetonitrile is reacted with ozone under ultraviolet light to obtain liquid and gaseous products. The preparation method of the organic amine supported catalyst includes: mixing an organic amine with a silane coupling agent and adding it to a first organic solvent, heating and stirring, then adding a supported phase while maintaining heating and stirring, cooling, filtering and drying, wherein the silane coupling agent is selected from tert-butyltrimethylsiloxane and / or tert-butyltrimethylchlorosilane, the organic amine is selected from at least one of dimethylamine, trimethylamine, ethylenediamine or hexylamine, and the supported phase is selected from one or more of silica, alumina, MCM-41 molecular sieve and MCM-48 molecular sieve; High-purity acetonitrile was obtained by first adsorption treatment of the liquid phase product using a first adsorbent. The first adsorbent is selected from one or more of 3A molecular sieve, 5A molecular sieve, 13X molecular sieve, polyacrylamide and carbon molecular sieve; and the first adsorbent is pretreated, which includes: impregnating the first adsorbent in sequence, removing impurities, washing, drying, depositing silicon with at least one silicon modifier selected from methyl orthosilicate, silicon tetrachloride or silicone oil, baking and activating, and then purging.

2. The method according to claim 1, wherein, The ratio of industrial acetonitrile to ozone, calculated based on the flow rate, is 50-200:1; and / or The ratio of industrial acetonitrile to the organic amine supported catalyst is 20-50:1; and / or The wavelength of the ultraviolet light is 200~365nm; the power of the ultraviolet light source is 10~60W; and / or The method also includes: The gaseous products are purified and then discharged into the atmosphere. The purification process includes using a second adsorbent to perform a second adsorption on the gaseous products. The conditions for the second adsorption include an adsorption pressure of 150~300 kPa and an adsorption temperature of 5~20℃. and / or The organic amine supported catalyst is regenerated after contact, and the regeneration process includes soaking the contacted organic amine supported catalyst in a desorption solution for regeneration.

3. The method according to claim 2, wherein, The ratio of industrial acetonitrile to ozone, calculated based on the flow rate, is 70-120:1; and / or The ratio of industrial acetonitrile to the organic amine supported catalyst is 30-40:1; and / or The wavelength of the ultraviolet light is 254~315nm; the power of the ultraviolet light source is 20~40W; and / or The mass concentration of the desorption solution is 1~10wt%.

4. The method according to claim 2, wherein, The desorption solution is selected from at least one of sodium thiosulfate aqueous solution, sodium bicarbonate aqueous solution, sodium carbonate aqueous solution, and sodium hydroxide aqueous solution; and / or The particle size of the second adsorbent is 4-8 mesh.

5. The method according to claim 2, wherein, The second adsorbent is selected from at least one of potassium iodide, sodium thiosulfate, methylcellulose, or carboxymethylcellulose.

6. The method according to claim 1 or 2, wherein, The preparation conditions for the organic amine supported catalyst include: a temperature of 60~120℃, a reaction time of 1~2h before the addition of the supported phase, and a reaction time of 2~4h after the addition of the supported phase; and / or The mass ratio of the organic amine to the silane coupling agent is 1:6~12; and / or The mass ratio of the organic amine to the first organic solvent is 1:100~400; and / or The first organic solvent is selected from at least one of ionic liquid, isopropanol, benzene, or methanol; and / or The mass ratio of the organic amine to the solid phase is 1:5~10.

7. The method according to claim 6, wherein, The preparation conditions for organic amine supported catalysts include: The mass ratio of the organic amine to the silane coupling agent is between 1:8 and 10; and / or The mass ratio of the organic amine to the first organic solvent is 1:200~300; and / or The ionic liquid is an imidazole ionic liquid and / or a quaternary ammonium ionic liquid.

8. The method according to claim 7, wherein, The ionic liquid is 1-ethyl-3-methylimidazolium acetate or 1-ethyl-3-methylimidazolium tetrafluoroborate.

9. The method according to claim 1 or 2, wherein, The conditions for the first adsorption treatment include: an adsorption pressure of 150~300 kPa and an adsorption temperature of 5~20℃; and / or The first adsorbent is impregnated with ethanol and / or ethylene glycol; and / or Purification was performed using an acid with a mass concentration of 3-10%; and / or Washing with ultrapure water; and / or The drying temperature is 140~180℃, and the drying time is 2~6h; and / or The silicon deposition process includes placing the first adsorbent into a second organic solvent containing a silicon modifier and heating it until the second organic solvent is completely evaporated.

10. The method according to claim 9, wherein, The acid is selected from dilute hydrochloric acid or dilute nitric acid; and / or The ultrapure water is classified as Grade I; and / or The heat treatment in the silicon deposition process is 90~110℃; and / or The first adsorbent is subjected to silicon deposition treatment using a second organic solvent containing 5-20% by mass of a silicon modifier; and / or The second organic solvent is selected from at least one of 3-methylpentane, 2-dimethylbutane, or benzene; and / or The baking temperature is 400~500℃, and the baking time is 3~5 hours.

11. The method according to claim 9, wherein, Desorption of the first and second adsorbents after adsorption is performed using desorption gas; and / or The particle size of the first adsorbent is 4-8 mesh.

12. The method according to claim 11, wherein, The desorption pressure is 20~60 kPa, and the desorption temperature is 70~100℃; and / or The desorption gas is selected from at least one of high-purity nitrogen, high-purity argon, high-purity carbon dioxide, or high-purity helium.

13. The method according to claim 1 or 2, wherein, The composition of the industrial acetonitrile, by mass fraction, is: acetonitrile ≥ 99.5%, moisture ≤ 0.35%, propionitrile ≤ 1000 ppm, acrylonitrile ≤ 200 ppm, hydrogen cyanide ≤ 100 ppm, and other single organic impurities ≤ 50 ppm. and / or The contact time between the industrial acetonitrile and the ozone is 10-30 minutes.

14. An apparatus for purifying industrial acetonitrile to prepare high-purity acetonitrile, characterized in that, The device includes: The reaction unit includes a reaction tower (2), the top of which is provided with a first feed port and the bottom of which is provided with an ozone feed port, so that the industrial acetonitrile fed from the first feed port and the ozone fed from the ozone feed port can come into countercurrent contact inside the reaction tower (2); the top of the inside of the reaction tower (2) is fixed with an ultraviolet light emitting device by a bracket, which is used to make the industrial acetonitrile come into contact with ozone and organic amine supported catalyst under ultraviolet light irradiation to obtain liquid phase products and gas phase products; An adsorption unit connected to the reaction unit includes an adsorption column (5), the upper part of which is connected to the lower part of the reaction tower (2), for performing a first adsorption treatment on the liquid phase product from the reaction unit to obtain high-purity acetonitrile. The tail gas treatment unit connected to the reaction unit includes a waste removal column (4) for purifying the gaseous products before discharging them into the atmosphere; The waste removal column (4), the reaction tower (2), and the adsorption column (5) are connected in series in sequence. The reaction tower (2) is equipped with a catalyst box for fixing the catalyst, which can pass through the gas phase and the liquid phase.

15. The device according to claim 14, wherein, The reaction tower (2) is equipped with a stirring paddle, which is fixed by a bracket connected to the inner wall of the reaction tower. and / or The top of the reaction tower (2) is provided with a liquid distribution structure for dispersing industrial acetonitrile, located above the ultraviolet light emitting device; and / or The bottom of the reaction tower (2) is provided with a gas distribution structure for dispersing ozone.

16. The device according to claim 15, wherein, The number of light sources in the ultraviolet light emitting device is 1 to 2; and / or The liquid distribution structure is connected to the sprayer at the first inlet; and / or The gas distribution structure is a porous membrane.

17. The device according to claim 14, wherein, The reaction tower (2) is provided with a second feed inlet for the feed desorption liquid to soak and regenerate the organic amine supported catalyst; and / or The reaction tower is connected to the desorption tank (6) for introducing the soaked and regenerated desorption liquid into the desorption tank (6). and / or The lower part of the adsorption (5) column is provided with a high-purity acetonitrile outlet and a desorption gas inlet, which are used to introduce desorption gas through the desorption gas inlet to desorb the adsorption column (5), the reaction tower (2) and the waste removal column (4).

18. The device according to claim 17, wherein, The second feed inlet is connected to the sprayer; and / or The desorption tank (6) is connected to the waste removal column (4) and is used to introduce desorbed gas into the desorption tank (6).

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