Ultra-clean high-purity acetonitrile and preparation method thereof

Abstract

The invention relates to the field of industrial acetonitrile purification, in particular to ultra-clean high-purity acetonitrile and a preparation method thereof. In the ultra-clean high-purity acetonitrile, the acetonitrile content is not lower than 99.999%, the acetic acid content is not higher than 10ppm, and the propionitrile content is not higher than 10ppm. The ultra-clean high-purity acetonitrile disclosed by the invention has the advantages of high quality (low impurity content) and high acetonitrile purity.

Description

Technical Field

[0001] The present invention relates to the field of industrial acetonitrile purification, and particularly to an ultra-high purity acetonitrile and a preparation method thereof. Background Art

[0002] Ultra-high purity reagents are generally referred to as process chemicals internationally and are special chemicals used in the manufacturing process of large-scale integrated circuits and high-grade semiconductor devices. The product purity and cleanliness have a very important impact on the product performance of integrated circuit electronic components.

[0003] Acetonitrile, also known as methyl cyanide, has excellent solvent properties and is an important organic intermediate, which is widely used in various fields of the chemical industry. As an organic solvent, ultra-high purity acetonitrile has strong polarity and good solubility in organic substances, high molecular compounds, and inorganic salts. It is an excellent semiconductor cleaning agent in the production process of integrated circuit electronic components. At present, industrial acetonitrile is mainly obtained by refining and purifying by-products of crude acetonitrile produced by the ammoxidation of propylene to produce acrylonitrile, and contains impurities such as hydrogen cyanide, ammonia, acetone, propionitrile, water, allyl alcohol, acetic acid, methanol, oxazole, acrylonitrile, and unsaturated nitriles.

[0004] CN113956179A uses a non-polar carbon material to adsorb impurities in crude acetonitrile, and after dehydration treatment, acetonitrile with a mass percentage content greater than 99.9% is obtained. CN111574404A discloses a refining method and a refining device for high-purity acetonitrile. After the crude acetonitrile is preliminarily decontaminated by decyanation, ethylenediamine and formaldehyde are added to the acetonitrile and its azeotrope, and after subsequent decontamination, acetonitrile with a mass percentage content of 99.5% is obtained. This method will introduce impurities of ethylenediamine and formaldehyde, which will increase the difficulty of subsequent impurity removal, and the purity of the acetonitrile obtained by this method is relatively low. CN109704990A refines high-purity acetonitrile by distillation, chemical treatment, and adsorption methods to obtain reagent-grade acetonitrile with a mass percentage content greater than 99.99%. This method will generate additional alkaline waste liquid after chemical treatment, and at the same time, acid waste liquid will also be generated when reacting with concentrated sulfuric acid, increasing the waste liquid treatment cost. CN106674049A uses a chromatography column filled with activated carbon to remove impurities, adds inorganic salts to remove water, and distills to obtain chromatographic grade acetonitrile. This method will generate inorganic salt waste liquid, and at the same time, the acetonitrile treatment capacity is small, which is not conducive to the large-scale production of acetonitrile. CN106631890A discloses a process for refining acetonitrile. The low-boiling impurities in the crude acetonitrile are removed by flash evaporation. After adding a strong oxidant and an alkali, the acetonitrile permeate is obtained by pervaporation, and the acetonitrile with a mass percentage content greater than 99.99% is obtained by distillation separation. This method uses a strong oxidant and an alkali in chemical treatment, which will generate alkaline waste liquid, and the separation difficulty and cost are relatively high.

[0005] In the prior art, there is little information on the preparation of ultra-high purity electronic-grade acetonitrile. The traditional batch oxidation to remove organic impurities in acetonitrile will reduce the acetonitrile yield, increase the generation of "three wastes", and increase the production cost of ultra-high purity acetonitrile. Summary of the Invention

[0006] The object of the present invention is to overcome the problems existing in the prior art, such as low acetonitrile yield, low purity, large amount of waste liquid generation, and difficulty in continuous production. The present invention provides an ultra-high purity acetonitrile and a preparation method thereof. The preparation method has the characteristics of being continuous, environmentally friendly, efficient, and having high product purity and quality.

[0007] To achieve the above object, on the one hand, the present invention provides an ultra-high purity acetonitrile, in which the acetonitrile content is not less than 99.999%, the acetic acid content is not more than 10 ppm, and the propionitrile content is not more than 10 ppm.

[0008] On the second aspect, the present invention provides a preparation method of the ultra-high purity acetonitrile described in the first aspect. The method includes: after the acetonitrile raw material is subjected to the first ion exchange treatment, it is subjected to reactive distillation under a metal oxide catalyst and an oxygen-containing atmosphere, and the side-stream logistics of the reactive distillation is subjected to purification treatment and then the product logistics is taken out from the side line; optionally, the product logistics taken out from the side line is successively subjected to the second ion exchange treatment, dehydration treatment, and membrane separation treatment.

[0009] Through the above technical solutions, the present invention has the following beneficial effects:

[0010] The ultra-high purity acetonitrile of the present invention has the advantages of high quality (low impurity content) and high acetonitrile purity.

[0011] By adopting the preparation method of the present invention, through the first ion exchange treatment and the reactive distillation treatment under a metal oxide catalyst and an oxygen-containing atmosphere in sequence, combined with the distillation technology, the quality of the ultra-high purity acetonitrile product can be significantly improved, and the preparation requirements of integrated circuit electronic components can be met. Description of the Drawings

[0012] Figure 1 It is a schematic flow chart of an apparatus and method for preparing ultra-high purity acetonitrile provided by the present invention.

[0013] Description of the Reference Numerals

[0014] A - Acid-base neutralization tower, B - Reactive distillation tower, C - Purification tower, D - Ion adsorption tower, E - Water absorption tower, F - Membrane separation device, 1 - Cation exchange resin, 2 - Anion exchange resin, 3 - Metal oxide catalyst, 4 - Anion exchange resin, 5 - Cation exchange resin, 6 - Water absorption filler, 7 - Ultrafiltration membrane, 8 - Top condenser, 9 - Reboiler at the bottom of the tower, 10 - Heat exchanger. Detailed Embodiments

[0015] The endpoints and any values within the ranges disclosed in this document are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in this document.

[0016] The present invention provides an ultra-high purity and high-purity acetonitrile, in which the acetonitrile content is not less than 99.999%, the acetic acid content is not more than 10 ppm, and the propionitrile content is not more than 10 ppm.

[0017] According to a preferred embodiment of the present invention, in the ultra-high purity and high-purity acetonitrile, the hydrocyanic acid content is not more than 10 ppm, the allyl alcohol content is not more than 10 ppm, the methanol content is not more than 10 ppm, the acrylonitrile content is not more than 10 ppm, and the oxazole content is not more than 10 ppm.

[0018] According to a preferred embodiment of the present invention, in the ultra-high purity and high-purity acetonitrile, the content of a single metal ion is not more than 100 ppt, preferably not more than 10 ppt. The metal ions include, for example, at least one of Zn, Ba, Cr, Al, Sn, Li, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, and Pb.

[0019] According to a preferred embodiment of the present invention, in the ultra-high purity and high-purity acetonitrile, the content of a single acid radical ion and / or chloride ion is not more than 50 ppt, preferably not more than 1 ppt. The acid radical ions include, for example, NO 3 - 、PO 4 3- 、SO 4 2- at least one of them.

[0020] According to a preferred embodiment of the present invention, in the ultra-high purity and high-purity acetonitrile, the content of particles with a size greater than 2 μm is not more than 25 particles·ml -1 .

[0021] The present invention provides a method for preparing the above-mentioned ultra-high purity and high-purity acetonitrile. The method includes: after the acetonitrile raw material undergoes a first ion exchange treatment, it undergoes reactive distillation under a metal oxide catalyst and an oxygen-containing atmosphere, and the side stream of the reactive distillation is subjected to a refining treatment and then the product stream is withdrawn from the side stream; optionally, the product stream withdrawn from the side stream is sequentially subjected to a second ion exchange treatment, a dehydration treatment, and a membrane separation treatment.

[0022] By adopting the preparation method of the present invention, through sequentially performing a first ion exchange treatment and a reactive distillation treatment in the presence of a metal oxide catalyst and an oxygen-containing atmosphere, the quality of the ultra-high purity acetonitrile product can be significantly improved by combining the distillation technology, and the preparation requirements of integrated circuit electronic components can be met.

[0023] According to a preferred embodiment of the present invention, the steps of the first ion exchange treatment and the second ion exchange treatment respectively include: first performing an anion exchange resin treatment and then performing a cation exchange resin treatment.

[0024] According to a preferred embodiment of the present invention, both the first ion exchange treatment and the second ion exchange treatment are carried out in a packed tower, the packed tower is divided into two sections of packing, and the volume ratio of the packed anion exchange resin to the packed cation exchange resin is 1:2 - 2:1.

[0025] According to a preferred embodiment of the present invention, the anion exchange resin includes a strongly basic styrene-based anion exchange resin or a weakly basic acrylic-based anion exchange resin; and / or the cation exchange resin includes a strongly acidic styrene-based cation exchange resin or a weakly acidic acrylic-based cation exchange resin; preferably, the particle size of the aforementioned anion / cation exchange resin is 0.3 - 1.2 mm.

[0026] According to a preferred embodiment of the present invention, the conditions of the first ion exchange treatment include: the space velocity of the acetonitrile raw material is 0.1 - 5.0 h -1 , and the temperature is 25 - 50 °C.

[0027] According to a preferred embodiment of the present invention, the conditions of the second ion exchange treatment include: the liquid phase space velocity is 0.1 - 3.0 h -1 .

[0028] According to a preferred embodiment of the present invention, the metal element in the metal oxide catalyst is selected from at least one of Fe, Mg, Mo, Sn, Co, Mn, Ce, V, Cu, and Cr.

[0029] According to a preferred embodiment of the present invention, the size of the metal oxide catalyst is 20 - 100 mesh.

[0030] According to a preferred embodiment of the present invention, the oxygen-containing gas is selected from at least one of air, oxygen, and ozone.

[0031] According to a preferred embodiment of the present invention, the conditions of the reactive distillation include: the tower bottom temperature is 95 - 130 °C, the pressure is 0.12 - 0.3 MPa, the reflux ratio is 10 - 60, the side line discharge port is located in the stripping section, and the side line discharge is in the form of gas or liquid extraction.

[0032] According to a preferred embodiment of the present invention, the reactive distillation column for reactive distillation is a sieve plate column and / or a packed column. The trays of the sieve plate column are one of vertical sieve trays, bubble cap three-dimensional sieve trays, rectangular vertical sieve trays, and high-efficiency flow-guided sieve trays. The packed column is a random packing and / or a structured packing. The middle section of the reactive distillation column is a catalyst packing section. The bottom of the catalyst packing section of the reactive distillation column is fed with an acetonitrile-containing material, and the bottom of the stripping section of the reactive distillation column is fed with a gas.

[0033] According to a preferred embodiment of the present invention, the packing section of the reactive distillation column accounts for 1 / 5 - 1 / 3 of the total column height.

[0034] According to a preferred embodiment of the present invention, the conditions for the refining treatment include: the column bottom temperature is 110 - 155 °C, the pressure is 0.2 - 0.6 MPa, the reflux ratio is 1 - 20, the side line discharge port is located in the rectifying section, and the side line discharge is a gas-phase or liquid-phase draw.

[0035] According to a preferred embodiment of the present invention, the column bottom product and part of the top product of the refining treatment are recycled back to the reactive distillation.

[0036] According to a preferred embodiment of the present invention, the refining treatment is carried out in a refining column. The refining column is a sieve plate column and / or a packed column. The trays of the sieve plate column are one of vertical sieve trays, bubble cap three-dimensional sieve trays, rectangular vertical sieve trays, or high-efficiency flow-guided sieve trays. The packed column is a random packing and / or a structured packing.

[0037] According to a preferred embodiment of the present invention, the conditions for the dehydration treatment include: the liquid hourly space velocity is 0.1 - 2.5 h -1 .

[0038] According to a preferred embodiment of the present invention, the dehydrating agent used for the dehydration treatment is selected from at least one of molecular sieves, water-absorbing resins, anhydrous sodium sulfate, and calcium chloride. Preferably, the molecular sieve is at least one of 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, and 13X molecular sieve.

[0039] According to a preferred embodiment of the present invention, the conditions for the membrane separation treatment include: the liquid phase pressure at the feed inlet is 0.2 - 1.0 MPa.

[0040] According to a preferred embodiment of the present invention, the membrane module used for the membrane separation treatment is one of plate type, tubular type, spiral wound type, hollow fiber type, submerged type, and slice type. Preferably, the ultrafiltration membrane material in the membrane module is at least one of cellulose esters, polysulfones, polyolefins, and fluorine-based materials. More preferably, the pore size of the ultrafiltration membrane is 1 - 100 nm.

[0041] According to a preferred embodiment of the present invention, the acetonitrile raw material is industrial-grade acetonitrile with a mass percentage of acetonitrile greater than 99%. The composition of the industrial-grade acetonitrile is shown in Table 1 and Table 2.

[0042] As Figure 1 shown, the present invention provides a schematic flow diagram of a device and method for preparing ultra-high purity acetonitrile in a preferred embodiment:

[0043] The device includes an acid-base neutralization tower A (the first tower for ion exchange treatment), a reactive distillation tower B, a refining tower C, an ion adsorption tower D (the second tower for ion exchange treatment), a water absorption tower E, and a membrane separation device F, which are connected in sequence through pipelines. The feed inlet of the reactive distillation tower A is connected to the top outlet of the acid-base neutralization tower B. The feed inlet of the refining tower C is connected to the side-line outlet of the reactive distillation tower B. The bottom feed inlet of the ion adsorption tower D is connected to the side-line outlet of the refining tower C. The bottom feed inlet of the water absorption tower E is connected to the top of the ion adsorption tower D. The feed inlet of the membrane filtration device F is connected to the top of the water absorption tower E. The reactive distillation tower B and the refining tower C are respectively provided with a top condenser and a bottom reboiler.

[0044] The process includes the following steps:

[0045] S1. The acetonitrile raw material enters the acid-base neutralization tower and, through interaction with the ion exchange resin packing in the tower, removes acid or base impurities in the raw material acetonitrile.

[0046] S2. The acetonitrile from which acid and base impurities have been removed enters the reactive distillation tower. The feed inlet is at the bottom of the middle catalyst loading section, and the oxidation gas feed inlet is at the bottom of the stripping section. Impurities in the acetonitrile such as acrylonitrile, acetone, methanol, oxazole, allyl alcohol, etc. react with the oxidation gas in the reaction section to form higher-boiling heavy components, and acetonitrile without light component impurities is obtained from the side line.

[0047] S3. The overhead fraction of the reactive distillation tower enters the refining tower to further remove light component impurities and / or heavy component impurities. The bottom product and the top product are refluxed to the feed inlet of the reactive distillation tower to improve the acetonitrile recovery rate. The high-purity acetonitrile product is withdrawn from the side line of the refining tower.

[0048] S4. The high-purity acetonitrile product enters the ion adsorption tower and, after being adsorbed by the anion / cation exchange resin in the tower, removes ionic impurities such as Zn, Ba, Cr, Al, Sn, Li, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Cl-, NO 3 - , PO 4 3- , SO 4 2- and other plasma impurities.

[0049] S5. The acetonitrile from which ionic impurities have been removed enters the water absorption tower to further remove moisture.

[0050] S6. The dehydrated acetonitrile enters the membrane separation device, and the particulate matter in the acetonitrile is filtered through the membrane module to obtain an ultra-high purity acetonitrile product.

[0051] The present invention will be described in detail below through examples. All the following examples are carried out in the Figure 1 device shown. The contents of organic substances such as acetonitrile, acetone, propionitrile, allyl alcohol, methanol, acrylonitrile, oxazole, and acetic acid in the raw materials and products are determined by gas chromatography, the content of hydrocyanic acid is determined by titration, and the water content is determined by the Karl Fischer method. The ion concentration in the raw materials and products is determined by inductively coupled plasma mass spectrometry, and the particle concentration is determined by a particle analyzer. Unless otherwise specified, the raw materials are commercially available products.

[0052] Example 1

[0053] The acid-base neutralization tower A has two sections of packing up and down. The lower section of the packing is a strongly basic styrene-based anion exchange resin, and the upper section of the packing is a strongly acidic styrene-based cation exchange resin. The particle size of the anion / cation exchange resin is 0.8 mm, and the volume ratio is 1:1; the reactive distillation tower B is a sieve plate tower, and the tower plate is a vertical sieve plate. The middle section of the reactive distillation tower B is a catalyst packing section. The catalyst is a composite metal oxide of Fe, Mo, and V, and the mass content of each metal is Fe:Mo:V = 5:2:3. The catalyst packing section accounts for 1 / 3 of the total tower height, the catalyst size is 60 mesh, the bottom of the catalyst packing section is the acetonitrile feed, and the air feed port is located at the bottom of the stripping section of the reactive distillation tower B; the refining tower C is a packed tower, and the packing method is structured packing; the ion adsorption tower D has two sections of packing up and down. The lower section of the packing is a strongly basic styrene-based anion exchange resin, and the upper section of the packing is a strongly acidic styrene-based cation exchange resin. The particle size of the anion / cation exchange resin is 0.8 mm, and the volume ratio is 1:1; the water absorption packing in the water absorption tower E is 5A molecular sieve and water absorption resin; the membrane module of the membrane filtration device F is a hollow fiber type, and the ultrafiltration membrane material is a fluorine material, and the membrane pore size is 10 nm.

[0054] It includes the following steps:

[0055] S1. The raw material acetonitrile enters the acid-base neutralization tower A, and through the action of the ion exchange resin packing in the tower, the acid or base impurities in the raw material acetonitrile are removed;

[0056] S2. The acetonitrile from which the acid-base impurities have been removed enters the reactive distillation tower B. The feed port is located at the bottom of the middle catalyst loading section, and the oxidation gas feed port is at the bottom of the stripping section. Impurities in the acetonitrile such as acrylonitrile, acetone, methanol, oxazole, and allyl alcohol react with the oxidation gas in the reaction section to form heavier components with higher boiling points, and acetonitrile free of light component impurities is obtained at the top of the tower;

[0057] S3. The overhead fraction of reactive distillation column B enters purification column C to further remove light or heavy component impurities. The bottom product and the overhead product are refluxed to the feed inlet of reactive distillation column C to improve the recovery rate of acetonitrile. High-purity acetonitrile product is withdrawn from the side stream of purification column C.

[0058] S4. The high-purity acetonitrile product enters ion adsorption column D. After being adsorbed by anion / cation exchange resins in the column, Zn, Ba, Cr, Al, Sn, Li, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Cl-, NO 3 - , PO 4 3- , SO 4 2- and other ionic impurities in the acetonitrile are removed.

[0059] S5. The acetonitrile from which ionic impurities have been removed enters water absorption column E to further remove moisture.

[0060] S6. The dehydrated acetonitrile enters membrane separation device F. Particulates in the acetonitrile are filtered by the membrane module to obtain an ultra-high purity acetonitrile product.

[0061] The acetonitrile space velocity in acid-base neutralization column A is 1.0 h -1 , and the operating temperature of acid-base neutralization column A is 30 °C; the number of trays in reactive distillation column B is 80, the bottom temperature is 113 °C, the pressure is 0.2 MPa, the reflux ratio is 60, the reflux temperature is 64 °C, the side stream outlet is located in the stripping section, and the side stream is withdrawn as a liquid phase; the number of theoretical trays in purification column C is 90, the bottom temperature is 142 °C, the pressure is 0.45 MPa, the reflux ratio is 12, the reflux temperature is 82 °C, the side stream outlet is located in the rectifying section, and the side stream is withdrawn as a gas phase; the liquid space velocity in ion adsorption column D is 1.5 h -1 ; the liquid space velocity in water absorption column E is 1.5 h -1 ; the liquid phase pressure at the feed inlet of membrane filtration device F is 0.6 MPa.

[0062] The composition of the acetonitrile product in this example is shown in Tables 1 and 2.

[0063] Example 2

[0064] Same as Example 1, except that the acid-base neutralization tower A has two sections of packing. The lower section of packing is weakly basic styrene-based anion exchange resin, and the upper section of packing is strongly acidic styrene-based cation exchange resin. The particle size of the anion / cation exchange resin is 0.8 mm, and the volume ratio is 1:1. The reactive distillation tower B is a packed tower with structured packing. The middle section of the reactive distillation tower B is a catalyst packing section. The catalyst is a composite metal oxide of Fe, Mn, and V, and the mass content of each metal is Fe:Mn:V = 3:1:1. The catalyst packing section accounts for 1 / 4 of the total tower height. The catalyst size is 60 mesh. The bottom of the catalyst packing section is for acetonitrile feeding, and the oxygen feeding port is located at the bottom of the stripping section of the reactive distillation tower B. The refining tower C is a packed tower with random packing. The ion adsorption tower D has two sections of packing. The lower section of packing is weakly basic styrene-based anion exchange resin, and the upper section of packing is strongly acidic styrene-based cation exchange resin. The particle size of the anion / cation exchange resin is 0.8 mm, and the volume ratio is 1:1. The water absorption packing in the water absorption tower E is 5A molecular sieve and water absorption resin. The membrane module of the membrane separation device F is tubular, and the ultrafiltration membrane material is polysulfone, with a membrane pore size of 10 nm.

[0065] The acetonitrile space velocity in the acid-base neutralization tower A is 1.5 h -1 , and the operating temperature of the acid-base neutralization tower A is 30 °C. The reactive distillation tower B has 80 theoretical plates. The tower bottom temperature is 113 °C, the pressure is 0.2 MPa, the reflux ratio is 40, the reflux temperature is 64 °C, the side draw port is located in the stripping section, and the side draw is a liquid-phase draw. The refining tower C has 100 theoretical plates. The tower bottom temperature is 147 °C, the pressure is 0.5 Mpa, the reflux ratio is 10, the reflux temperature is 85 °C, the side draw port is located in the rectifying section, and the side draw is a vapor-phase draw. The liquid-phase space velocity in the ion adsorption tower D is 2.0 h -1 ; the liquid-phase space velocity in the water absorption tower E is 1.5 h -1 ; the liquid-phase pressure at the feed port of the membrane filtration device F is 0.5 MPa.

[0066] The composition of the acetonitrile product in this example is shown in Table 1 and Table 2.

[0067] Example 3

[0068] Same as Example 1, except that the acid-base neutralization tower A has two sections of packing, the lower section of packing is a strongly basic styrene-based anion exchange resin, and the upper section of packing is a strongly acidic styrene-based cation exchange resin. The particle size of the anion / cation exchange resin is 0.6 mm, and the volume ratio is 1:1; the reactive distillation tower B is a packed tower, and the packing method is structured packing. The middle section of the reactive distillation tower B is a catalyst packing section, and the catalyst is a composite metal oxide of Fe, Mn, Ce, and V. The mass content of each metal is Fe:Mn:Ce:V = 5:1:1:3. The catalyst packing section accounts for 1 / 4 of the total tower height, the catalyst size is 60 mesh, the bottom of the catalyst packing section is the acetonitrile feed, and the air feed port is located at the bottom of the stripping section of the reactive distillation tower B; the refining tower C is a packed tower, and the packing method is structured packing; the ion adsorption tower D has two sections of packing, the lower section of packing is a strongly basic styrene-based anion exchange resin, and the upper section of packing is a strongly acidic styrene-based cation exchange resin. The particle size of the anion / cation exchange resin is 0.6 mm, and the volume ratio is 1:1; the water absorption packing in the water absorption tower E is water absorption resin and anhydrous sodium sulfate; the membrane module of the membrane filtration device F is a flat plate type, the ultrafiltration membrane material is a fluorine material, and the membrane pore size is 10 nm.

[0069] The acetonitrile space velocity in the acid-base neutralization tower A is 1.0 h -1 , the operating temperature of the acid-base neutralization tower A is 25 °C; the reactive distillation tower B has 75 theoretical plates, the tower bottom temperature is 120 °C, the pressure is 0.25 MPa, the reflux ratio is 40, the reflux temperature is 70 °C, the side draw port is located in the stripping section, and the side draw is liquid-phase extraction; the refining tower C has 120 theoretical plates, the tower bottom temperature is 138 °C, the pressure is 0.4 Mpa, the reflux ratio is 10, the reflux temperature is 75 °C, the side draw port is located in the rectifying section, and the side draw is gas-phase extraction; the liquid-phase space velocity in the ion adsorption tower D is 1.5 h -1 ; the liquid-phase space velocity in the water absorption tower E is 1.5 h -1 ; the liquid-phase pressure at the feed port of the membrane filtration device F is 0.6 MPa.

[0070] The composition of the acetonitrile product in this example is shown in Tables 1 and 2.

[0071] Example 4

[0072] Same as Example 1, except that the acid-base neutralization tower A has two sections of packing. The lower section of the packing is weakly basic acrylic anion exchange resin, and the upper section of the packing is weakly acidic acrylic cation exchange resin. The particle size of the anion / cation exchange resin is 0.6 mm, and the volume ratio is 1:1. The reactive distillation tower B is a sieve tray tower, and the trays are bubble-cap sieve trays. The middle section of the reactive distillation tower B is a catalyst packing section. The catalyst is a composite metal oxide of Fe, Mn, Ce, and V, and the mass content of each metal is Fe:Mn:Ce:V = 5:2:2:3. The catalyst packing section accounts for 1 / 4 of the total tower height. The catalyst size is 40 mesh. The bottom of the catalyst packing section is the acetonitrile feed, and the oxygen feed port is located at the bottom of the stripping section of the reactive distillation tower B. The refining tower C is a sieve tray tower, and the trays are bubble-cap sieve trays. The ion adsorption tower D has two sections of packing. The lower section of the packing is weakly basic acrylic anion exchange resin, and the upper section of the packing is weakly acidic acrylic cation exchange resin. The particle size of the anion / cation exchange resin is 0.6 mm, and the volume ratio is 1:1. The water absorption packing in the water absorption tower E is 3A molecular sieve and anhydrous sodium sulfate. The membrane module of the membrane filtration device F is a hollow fiber type, the ultrafiltration membrane material is a fluorine material, and the membrane pore size is 20 nm.

[0073] The acetonitrile space velocity in the acid-base neutralization tower A is 3.0 h -1 , the operating temperature of the acid-base neutralization tower A is 30 °C. The reactive distillation tower B has 90 trays, the bottom temperature of the tower kettle is 127 °C, the pressure is 0.3 MPa, the reflux ratio is 30, the reflux temperature is 80 °C, the side line outlet is located in the stripping section, and the side line discharge is liquid phase extraction. The refining tower C has 100 trays, the bottom temperature of the tower kettle is 147 °C, the pressure is 0.5 Mpa, the reflux ratio is 8, the reflux temperature is 85 °C, the side line outlet is located in the rectifying section, and the side line discharge is gas phase extraction. The liquid phase space velocity in the ion adsorption tower D is 2.5 h -1 ; the liquid phase space velocity in the water absorption tower E is 2.0 h -1 ; the liquid phase pressure at the feed port of the membrane filtration device F is 0.4 MPa.

[0074] The composition of the acetonitrile product in this example is shown in Table 1 and Table 2.

[0075] Example 5

[0076] Same as Example 1, except that the acid-base neutralization tower A has two sections of packing, the lower section of packing is strongly basic styrene-based anion exchange resin, and the upper section of packing is weakly acidic acrylic-based cation exchange resin. The particle size of the anion / cation exchange resin is 0.8 mm, and the volume ratio is 1:1; the reactive distillation tower B is a packed tower, and the packing method is random packing. The middle section of the reactive distillation tower B is the catalyst packing section, and the catalyst is a composite metal oxide of Fe and V, and the mass content of each metal is Fe:V = 5:3. The catalyst packing section accounts for 1 / 5 of the total tower height, the catalyst size is 40 mesh, the bottom of the catalyst packing section is the acetonitrile feed, and the ozone feed port is located at the bottom of the stripping section of the reactive distillation tower B; the refining tower C is a packed tower, and the packing method is structured packing; the ion adsorption tower D has two sections of packing, the lower section of packing is strongly basic styrene-based anion exchange resin, and the upper section of packing is weakly acidic acrylic-based cation exchange resin. The particle size of the anion / cation exchange resin is 0.8 mm, and the volume ratio is 1:1; the water absorption packing in the water absorption tower E is water absorption resin and calcium chloride; the membrane module of the membrane filtration device F is a spiral wound type, the ultrafiltration membrane material is cellulose ester, and the membrane pore size is 15 nm.

[0077] The acetonitrile space velocity in the acid-base neutralization tower A is 2.5 h -1 , the operating temperature of the acid-base neutralization tower A is 30 °C; the number of theoretical plates of the reactive distillation tower B is 60, the tower bottom temperature is 113 °C, the pressure is 0.2 MPa, the reflux ratio is 30, the reflux temperature is 60 °C, the side line outlet is located in the stripping section, and the side line discharge is liquid phase extraction; the number of theoretical plates of the refining tower C is 90, the tower bottom temperature is 132 °C, the pressure is 0.35 Mpa, the reflux ratio is 8, the reflux temperature is 66 °C, the side line outlet is located in the rectifying section, and the side line discharge is gas phase extraction; the liquid phase space velocity in the ion adsorption tower D is 2.0 h -1 ; the liquid phase space velocity in the water absorption tower E is 1.5 h -1 ; the liquid phase pressure at the feed port of the membrane filtration device F is 0.3 MPa.

[0078] The composition of the acetonitrile product in this example is shown in Tables 1 and 2.

[0079] Comparative Example 1

[0080] This comparative example is the same as the method of Example 1, and the difference between the two is that there is no anion / cation packing in the acid-base neutralization tower A, and the other conditions are the same. The product composition is shown in Tables 3 and 4.

[0081] Comparative Example 2

[0082] This comparative example is the same as the method of Example 3, and the difference between the two is that there is no gas feed in the reactive distillation tower B, and the other conditions are the same. The product composition is shown in Tables 3 and 4.

[0083] Table 1

[0084]

[0085] Table 2

[0086]

[0087] Table 3

[0088] Mass content Raw material Example 1 Comparative Example 1 Example 3 Comparative Example 2 SEMI C12 standard Acetonitrile / % 99.5 >99.999 99.99 >99.999 99.98 >99.9 Hydrocyanic acid / ppm 30 Not detected Not detected Not detected 18 <10 Acetone / ppm 30 Not detected Not detected Not detected 9 <10 Propionitrile / ppm 420 4 24 5 17 <10 Water / ppm 3300 Not detected Not detected Not detected Not detected <50 Allyl alcohol / ppm 470 2 2 3 86 <10 Methanol / ppm 50 Not detected Not detected Not detected 13 <10 Acrylonitrile / ppm 300 Not detected Not detected 1 34 <10 Oxazole / ppm 320 Not detected Not detected Not detected 11 <10 Acetic acid / ppm 70 Not detected 27 Not detected Not detected <10

[0089] Table 4

[0090]

[0091] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A super high purity and ultra clean acetonitrile, characterized in that, the content of acetonitrile in the super high purity and ultra clean acetonitrile is not less than 99.999%, the content of acetic acid is not higher than 10 ppm, and the content of propionitrile is not higher than 10 ppm.

2. The super high purity and ultra clean acetonitrile according to claim 1, wherein, the content of hydrocyanic acid in the super high purity and ultra clean acetonitrile is not higher than 10 ppm, the content of allyl alcohol is not higher than 10 ppm, the content of methanol is not higher than 10 ppm, the content of acrylonitrile is not higher than 10 ppm, and the content of oxazole is not higher than 10 ppm.

3. The super high purity and ultra clean acetonitrile according to claim 1 or 2, wherein, the content of a single metal ion in the super high purity and ultra clean acetonitrile is not higher than 100 ppt, preferably not higher than 10 ppt; and / or the content of a single acid radical ion and / or chloride ion in the super high purity and ultra clean acetonitrile is not higher than 50 ppt, preferably not higher than 1 ppt; and / or In the ultrapure acetonitrile, the content of particles with a size greater than 2 μm is not higher than 25 particles·ml -1 .

4. A preparation method of the super high purity and ultra clean acetonitrile according to any one of claims 1 - 3, characterized in that, the method comprises: after the acetonitrile raw material undergoes a first ion exchange treatment, it undergoes reactive distillation under a metal oxide catalyst and an oxygen-containing atmosphere, and the side stream of the reactive distillation is subjected to a refining treatment and then the product stream is withdrawn from the side line; optionally, the product stream withdrawn from the side line is sequentially subjected to a second ion exchange treatment, a dehydration treatment, and a membrane separation treatment.

5. The preparation method according to claim 4, wherein, the steps of the first ion exchange treatment and the second ion exchange treatment respectively comprise: first performing an anion exchange resin treatment and then a cation exchange resin treatment, preferably, the anion exchange resin includes a strongly basic styrene-based anion exchange resin or a weakly basic acrylic-based anion exchange resin; and / or the cation exchange resin includes a strongly acidic styrene-based cation exchange resin or a weakly acidic acrylic-based cation exchange resin; The conditions for the first ion exchange treatment include: the space velocity of the acetonitrile raw material is 0.1 - 5.0 h -1 , and the temperature is 25 - 50 °C. The conditions of the second ion exchange treatment include: the liquid hourly space velocity is 0.1 - 3.0 h -1 .

6. The preparation method according to claim 4 or 5, wherein, the metal element in the metal oxide catalyst is selected from at least one of Fe, Mg, Mo, Sn, Co, Mn, Ce, V, Cu, Cr; and / or the oxygen-containing gas is selected from at least one of air, oxygen, and ozone.

7. The preparation method according to any one of claims 4 - 6, wherein, the conditions of the reactive distillation include: the tower bottom temperature is 95 - 130 °C, the pressure is 0.12 - 0.3 MPa, the reflux ratio is 10 - 60, the side line discharge port is located in the stripping section, and the side line discharge is taken out as a gas phase or a liquid phase.

8. The preparation method according to any one of claims 4 - 7, wherein, the conditions of the refining treatment include: the tower bottom temperature is 110 - 155 °C, the pressure is 0.2 - 0.6 MPa, the reflux ratio is 1 - 20, the side line discharge port is located in the rectifying section, and the side line discharge is taken out as a gas phase or a liquid phase.

9. The preparation method according to any one of claims 4 - 8, wherein, The conditions for the dehydration treatment include: the liquid hourly space velocity is 0.1 - 2.5 h -1 ; and / or the dehydrating agent used in the dehydration treatment is selected from at least one of molecular sieve, water-absorbing resin, anhydrous sodium sulfate, and calcium chloride, and preferably the molecular sieve is at least one of 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, and 13X molecular sieve.

10. The preparation method according to any one of claims 4-9, wherein, the conditions of the membrane separation treatment include: the liquid phase pressure at the feed inlet is 0.2-1.0 MPa; and / or the membrane module used in the membrane separation treatment is one of flat plate type, tubular type, spiral wound type, hollow fiber type, submerged type and slice type. Preferably, the ultrafiltration membrane material in the membrane module is at least one of cellulose esters, polysulfones, polyolefins and fluorine materials. More preferably, the pore size of the ultrafiltration membrane is 1-100 nm.

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