Chelate resin, preparation method thereof and method for preparing electronic-grade isopropanol

Abstract

The invention relates to the field of isopropyl alcohol preparation, and discloses a chelate resin and a preparation method thereof, and a method for preparing electronic grade isopropyl alcohol, the method comprises the following steps: styrene-divinylbenzene polymeric microspheres are contacted with N-hydroxymethyl phthalimide, and an imidization reaction, a hydrolysis reaction and a carboxylation reaction are sequentially carried out. By using the chelate resin and the method for preparing the electronic-grade isopropanol, the content of isopropanol in the product can be effectively increased, and the content of water, zwitterions and particles can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of isopropanol preparation, specifically relating to a chelating resin and its preparation method, as well as a method for preparing electronic-grade isopropanol. Background Technology

[0002] Ultra-high purity electronic-grade isopropanol is widely used in wet processes such as cleaning and etching in semiconductor manufacturing, so the purity and cleanliness requirements for electronic-grade isopropanol are extremely high.

[0003] Existing isopropanol preparation processes include indirect propylene hydration, direct propylene hydration, and acetone hydrogenation. Among these, the indirect propylene hydration process is complex, the raw materials cause severe corrosion to equipment, and the resulting wastewater and exhaust gases pollute the environment. The direct propylene hydration process has a low single-pass propylene conversion rate, produces many byproducts, has high energy consumption, and faces significant challenges in separating large amounts of water. In contrast, the acetone hydrogenation method offers high acetone conversion and selectivity, fewer byproducts, milder reaction conditions, lower energy consumption, and less corrosion of equipment, making it suitable for the industrial production of electronic-grade isopropanol. CN107365246A proposes a full-temperature-range adsorption-extraction purification method. However, this extraction method requires the introduction of a new extractant into the isopropanol, increasing separation difficulty, energy consumption, process length, and operational complexity. CN111675598B proposes a production system for preparing electronic-grade isopropanol via acetone hydrogenation, including raw material transportation, molecular sieve dehydration, reaction, pressure swing adsorption, distillation, and filtration steps. Isopropanol purification technology plays a crucial role in the synthesis of electronic-grade isopropanol. Existing purification methods include distillation, chemical treatment, gas absorption, and resin adsorption. However, relying on distillation and rectification methods can only improve the purity of isopropanol, but it is difficult to improve its cleanliness. CN102898275B proposes a method for preparing high-purity isopropanol, which includes steps such as molecular sieve dehydration, resin dehydration, reverse osmosis, high-temperature rectification, ion exchange, and circulating filtration. The process is long and complex. However, the above methods are complex and the resulting product has a low isopropanol content.

[0004] Therefore, there is an urgent need for an apparatus and process to purify isopropanol to obtain electronic-grade isopropanol. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of long and complex processes in the preparation of electronic-grade isopropanol in the existing technology, and to provide a chelating resin, a method for preparing the same, and a method for preparing electronic-grade isopropanol.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a chelating resin, the method comprising: contacting styrene-divinylbenzene polymer microspheres with N-hydroxymethyl phthalimide, and sequentially performing an imidization reaction, a hydrolysis reaction and a carboxylation reaction.

[0007] A second aspect of the present invention provides a chelating resin prepared by the method described above, wherein the resin in the chelating resin column comprises polymer microspheres and modifying groups modified on the surface of the polymer microspheres, wherein the polymer microspheres are styrene-divinylbenzene polymer microspheres, and the structure of the modifying groups is shown in Formula 1 below.

[0008]

[0009] A third aspect of the present invention provides a method for preparing electronic-grade isopropanol, the method comprising: deionizing, dehydrating and degranulating crude isopropanol;

[0010] The method of deionization includes column chromatography of crude isopropanol through a chelating resin column, an acidic cation exchange resin column, and a basic anion exchange resin column; the resin of the chelating resin column is a chelating resin prepared by the method described above or a chelating resin as described above.

[0011] The beneficial effects of the present invention through the above technical solution include at least the following:

[0012] The method of this invention is simple, has low energy consumption, and can effectively increase the isopropanol content in the product; moreover, the method of this invention facilitates the continuous preparation of electronic-grade isopropanol. According to a preferred embodiment of this invention, the prepared electronic-grade isopropanol meets the SEMI C12(G4) standard set by the International Semiconductor Equipment and Materials Organization, with an isopropanol content greater than 99.9 wt%, a metal ion content as low as 0.1 ppb, a particle size of less than 0.2 μm as low as 5 particles / mL, and a water content reduced to 50 ppm. Detailed Implementation

[0013] 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.

[0014] In this invention, the preferred method for preparing the resin in the chelating resin column includes: contacting styrene-divinylbenzene polymer microspheres with N-hydroxymethyl phthalimide, and sequentially performing an imidization reaction, a hydrolysis reaction, and a carboxylation reaction.

[0015] According to the present invention, polymer microspheres can be obtained commercially or prepared in-house. Since the modification process mainly involves the imidization reaction between alkenyl functional groups and N-hydroxymethyl phthalimide, the inventors of this invention have discovered that using styrene-divinylbenzene polymer microspheres to provide alkenyl functional groups not only promotes the imidization reaction of N-hydroxymethyl phthalimide, facilitating the preparation of the chelating resin, but also enables the final chelating resin to possess strong physical properties, chemical stability, and thermal stability, extending the service life of the chelating resin and reducing costs and operational difficulties. Therefore, in the polymer constituting the polymer microspheres, as long as the polymer monomer includes styrene-divinylbenzene, regardless of whether it contains other groups or components that can enhance or reduce the deionization effect, strengthen the physical properties of the resin, or have any beneficial or harmful effects on the resin, it falls within the scope of protection of this invention.

[0016] According to a preferred embodiment of the present invention, the resin prepared using styrene-divinylbenzene polymer microspheres can improve the efficiency of resin preparation and maximize the deionization capability of the resin column.

[0017] In this invention, the molar ratio of the structural units provided by styrene to those provided by divinylbenzene in the styrene-divinylbenzene polymer microspheres is preferably (2-30):1, more preferably (8-15):1.

[0018] In this invention, the average particle size of the styrene-divinylbenzene polymer microspheres is preferably 200-1000 μm, more preferably 600-900 μm.

[0019] In this invention, the weight-average molecular weight of the styrene-divinylbenzene polymer microspheres is preferably 10. 5 -10 8 g / mol.

[0020] In this invention, the imidization reaction method preferably includes: in the presence of a solvent, contacting styrene-divinylene polymer microspheres and N-hydroxymethyl phthalimide and sequentially performing a first imidization and a second imidization to obtain imidized microspheres. The temperature of the first imidization is preferably 10-30°C higher than that of the second imidization. More preferably, the reaction temperature is lowered so that it is 15-25°C lower than that of the original imidization reaction.

[0021] The imidization can be carried out at a constant temperature. However, the inventors of this invention have discovered that by first carrying out the imidization reaction at a higher temperature for a period of time, and then slightly lowering the reaction temperature to 10-30°C lower than the original imidization reaction temperature, the conversion rate of N-hydroxymethyl phthalimide and the selectivity of the imidization product can be significantly improved, and the occurrence of side reactions can be reduced.

[0022] Preferably, the mass ratio of styrene-diethylene polymer microspheres, N-hydroxymethyl phthalimide, and solvent is 1:(1-5):(5-50), more preferably 1:(1-1.5):(15-20). It is understood that increasing the amount of N-hydroxymethyl phthalimide in the imidization reaction system and reducing the amount of solvent can improve the conversion rate of the styrene-diethylene polymer, but it also inevitably increases the reaction cost. The inventors have found that the resin prepared with the best deionization effect is obtained when the mass ratio of styrene-diethylene polymer microspheres, N-hydroxymethyl phthalimide, and solvent is 1:1.1-1.3:16-20.

[0023] Preferably, the solvent is at least one selected from 1,2-dichloroethane, carbon tetrachloride, and toluene, and more preferably 1,2-dichloroethane.

[0024] In this invention, the hydrolysis reaction method includes: hydrolyzing imidized microspheres in the presence of an alkaline substance to obtain hydrolyzed microspheres.

[0025] Preferably, the amount of alkaline substance used is 1-15 grams per gram of styrene-divinylbenzene polymer microspheres.

[0026] Preferably, the alkaline substance is at least one selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide, with sodium hydroxide being the most preferred.

[0027] In this invention, the hydrolysis reaction is carried out by placing the imidized microspheres in an alkaline solution containing an alkaline substance for hydrolysis, wherein the content of the alkaline substance in the alkaline solution is 2-30 wt%.

[0028] In this invention, the carboxylation reaction method includes: contacting hydrolyzed microspheres with acetate to perform a first carboxylation and a second carboxylation to obtain carboxylated microspheres, wherein the temperature of the first carboxylation is 10-30°C lower than that of the second carboxylation, preferably, the temperature of the first carboxylation is 15-25°C lower than that of the second carboxylation.

[0029] According to the present invention, although carboxylation is conventionally carried out at a constant temperature, the inventors of the present invention have discovered that by first carrying out the carboxylation reaction at a relatively high temperature for a period of time, and then slightly increasing the reaction temperature to be 10-30°C higher than the original carboxylation reaction temperature, the conversion rate and selectivity of the carboxylation product can be significantly improved, and the occurrence of side reactions can be reduced. Preferably, the reaction temperature is increased to be 15-25°C higher than the original carboxylation reaction temperature.

[0030] Preferably, the acetate is used in the form of an acetate solution, wherein the acetate content in the acetate solution is 5-30 wt%.

[0031] Preferably, the mass ratio of the acetate to the hydrolyzed microspheres is (0.5-15):1.

[0032] Preferably, the acetate is at least one of sodium acetate, potassium acetate, and ammonium acetate, and more preferably sodium acetate.

[0033] In this invention, the reaction conditions for the first iminolation include: a temperature preferably of 75-85°C, for example, a range or any value within a range of 75°C, 75.5°C, 76°C, 76.5°C, 77°C, 77.5°C, 78°C, 78.5°C, 79°C, 79.5°C, 80°C, 80.5°C, 81°C, 81.5°C, 82°C, 82.5°C, 83°C, 83.5°C, 84°C, 84.5°C, 85°C or higher; and a time preferably of 1-20 hours, for example, a range or any value within a range of 1 hour, 5 hours, 8 hours, 11 hours, 13 hours, 17 hours, 20 hours or higher.

[0034] In this invention, the reaction conditions for the second iminolation include: a temperature preferably of 55-65°C, for example, any value within or above of 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, or any value within that range; and a time preferably of 0.5-20 h, for example, any value within or above of 0.5 h, 1 h, 5 h, 8 h, 11 h, 13 h, 17 h, 20 h, or any value within that range.

[0035] In this invention, the reaction conditions for the hydrolysis reaction include: the temperature is preferably 35-45℃, for example, it can be any value within a range of 35℃, 36℃, 37℃, 38℃, 39℃, 40℃, 41℃, 42℃, 43℃, 44℃, 45℃ or above; and the reaction time is preferably 2-20h, for example, it can be any value within a range of 2h, 5h, 8h, 11h, 13h, 17h, 20h or above.

[0036] In this invention, the reaction conditions for the first carboxylation include: a temperature preferably of 55-65°C, for example, a range or any value within a range of 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C or higher; and a time preferably of 1-20 hours, for example, a range or any value within a range of 1 hour, 5 hours, 8 hours, 11 hours, 13 hours, 17 hours, 20 hours or higher.

[0037] In this invention, the reaction conditions for the second carboxylation include: a temperature preferably of 75-85°C, for example, a range or any value within the range of 75°C, 75.5°C, 76°C, 76.5°C, 77°C, 77.5°C, 78°C, 78.5°C, 79°C, 79.5°C, 80°C, 80.5°C, 81°C, 81.5°C, 82°C, 82.5°C, 83°C, 83.5°C, 84°C, 84.5°C, 85°C or higher; and a time of 5-20 hours, for example, a range or any value within the range of 5 hours, 8 hours, 11 hours, 13 hours, 17 hours, 20 hours or higher.

[0038] In this invention, the method may further include: washing with water and drying after the imidization reaction and the hydrolysis reaction, respectively.

[0039] In this invention, the method may further include: washing with water, acid washing, and drying after the carboxylation reaction, wherein the acid washing liquid is an acidic aqueous solution, preferably a 3-10 wt% HCl aqueous solution.

[0040] According to the present invention, the water used for washing is preferably pure water that does not contain anions and cations.

[0041] According to the most preferred embodiment of the present invention, the preparation process of the chelating resin is as follows:

[0042] Styrene-divinylbenzene polymeric microspheres were reacted with N-hydroxymethyl phthalimide in 1,2-dichloroethane solvent at 78-82℃ for 12-14 h, followed by a further reaction at 58-62℃ for 4.5-5.5 h. The microspheres were then removed from the solvent, washed, and dried to obtain imidized microspheres. The mass ratio of styrene-divinylbenzene polymeric microspheres, N-hydroxymethyl phthalimide, and solvent was 1:1.1-1.5:16-20. The dried imidized microspheres were then reacted in an alkaline aqueous solution (3-7 wt% sodium hydroxide solution) for 8-12 h to obtain hydrolyzed microspheres (the amount of sodium hydroxide used was 1-21 per gram of styrene-divinylbenzene polymeric microspheres). The reaction temperature was 38-42℃. After the reaction, the hydrolyzed microspheres were washed and dried. Take 30-40g of microspheres and place them in 600-1000ml of sodium acetate aqueous solution (sodium acetate content is 5-30wt%). React at 58-62℃ for 12-14h, and then react at 78-82℃ for 1-3h. Finally, wash the obtained microspheres with water, acid wash and dry to obtain chelating resin.

[0043] In this invention, the resin in the chelating resin column comprises polymer microspheres and modifying groups on the surface of the polymer microspheres. Preferably, the polymer microspheres are styrene-divinylbenzene polymer microspheres, and the structure of the modifying groups is preferably shown in Formula 1 below.

[0044]

[0045] The chelating resin obtained by this invention is coated with iminodiacetic acid.

[0046] According to some preferred embodiments of the present invention, the chelating resin prepared by the present invention has a good removal effect on metal ions and even chloride ions, and can significantly reduce Na, Fe, Mn, Sn, Zr and Cl chloride ions in crude isopropanol.

[0047] A third aspect of the present invention provides a method for preparing electronic-grade isopropanol, the method comprising: deionizing, dehydrating and degranulating crude isopropanol;

[0048] The method of deionization includes column chromatography of crude isopropanol through a chelating resin column, an acidic cation exchange resin column, and a basic anion exchange resin column; the resin of the chelating resin column is a chelating resin prepared by the method described above or a chelating resin as described above.

[0049] In this invention, the method of deionization also includes nanofiltration membrane filtration.

[0050] According to the present invention, the device for removing ions is also referred to as an ion remover, and the device for dehydration is also referred to as a dehydrator.

[0051] Preferably, the nanofiltration membrane used for nanofiltration can be a polyethersulfone nanofiltration membrane.

[0052] Preferably, the molecular weight cutoff of the nanofiltration membrane used for nanofiltration is 120-210 g / mol.

[0053] Preferably, the conditions for nanofiltration include: a temperature of 25-50°C and a pressure difference of 0.1-0.3 MPa.

[0054] According to the present invention, when using nanofiltration membranes of the types and molecular weight cutoffs described above to deionize isopropanol solutions containing metal ions, it is possible to remove a portion of the metal ions while retaining the isopropanol product to the maximum extent, thereby reducing the waste of isopropanol.

[0055] According to the present invention, the "pressure difference" refers to the pressure difference generated across the nanofiltration membrane before and after the material flows through it. This pressure difference is the main driving force propelling the material through the membrane. Generally, as the operating time increases, the pressure difference will gradually increase due to membrane surface fouling, clogging, and other reasons. In practical applications, a reasonable pressure difference range usually needs to be determined based on the specific membrane system design and operating conditions. All pressure differences mentioned below refer to the pressure difference generated across the membrane before and after the material flows through the device; this will not be elaborated further in the following sections of the present invention.

[0056] In this invention, the average particle size of the resin in the chelating resin column can be 0.4-1.2 mm, preferably 0.9-1.1 mm.

[0057] In this invention, the operating conditions of the chelating resin column include: a temperature preferably of 20-55℃, a pressure difference preferably of 0.01-0.1 MPaG, and a flow rate preferably of 8-12 BV / h.

[0058] In this invention, the average particle size of the resin in the acidic cation exchange resin column can be 0.4-1.4 mm, but according to a preferred embodiment of the invention, the average particle size is preferably 0.9-1.1 mm.

[0059] In this invention, the operating conditions of the acidic cation exchange resin column include: a temperature preferably of 20-55℃, a pressure difference preferably of 0.01-0.1 MPaG, and a flow rate preferably of 8-12 BV / h.

[0060] In this invention, the average particle size of the resin in the alkaline anion exchange resin column can be 0.3-1.4 mm, but according to a preferred embodiment of the invention, the average particle size is preferably 0.6-0.9 mm.

[0061] In this invention, the operating conditions of the alkaline anion exchange resin column include: a temperature preferably of 20-55℃, a pressure difference preferably of 0.01-0.1 MPaG, and a flow rate preferably of 8-12 BV / h.

[0062] According to the present invention, the chelating resin column, the acidic cation exchange resin column, and the basic anion exchange resin column are used in series. The series order can be adjusted according to actual conditions. It can be chelating resin column, acidic cation exchange resin column, and basic anion exchange resin column; it can also be basic anion exchange resin column, chelating resin column, and acidic cation exchange resin column; or it can be chelating resin column, basic anion exchange resin column, and acidic cation exchange resin column, as long as the chelating resin column is used before the acidic cation exchange resin column. Furthermore, it is understood that the number of chelating resin column, acidic cation exchange resin column, and basic anion exchange resin column can be one, multiple, or any integer greater than one. However, any chelating resin column provided by the present invention or chelating resin obtained using the preparation method provided by the present invention falls within the protection scope of the present invention.

[0063] According to a preferred embodiment of the present invention, the chelating resin column, the acidic cation exchange resin column, and the basic anion exchange resin column are used in series sequentially to obtain electronic-grade isopropanol with a total metal ion (cation) content of less than 0.11 μg / kg. According to another preferred embodiment of the present invention, the basic anion exchange resin column, the chelating resin column, and the acidic cation exchange resin column are used in series sequentially to obtain electronic-grade isopropanol with a total chloride ion content of less than 44 μg / kg.

[0064] In this invention, the dehydration method is molecular sieve dehydration, preferably, at least one of molecular sieve and molecular sieve membrane is used for dehydration.

[0065] Preferably, the molecular sieve is at least one of type X molecular sieve and type A molecular sieve, and more preferably 3A molecular sieve.

[0066] Preferably, the molecular sieve membrane is at least one of NaA-type inorganic molecular sieve pervaporation membrane, polyvinyl alcohol pervaporation membrane, and polyimide pervaporation membrane, and more preferably a NaA-type inorganic molecular sieve pervaporation membrane.

[0067] Preferably, the molecular sieve and the molecular sieve membrane are used in series; more preferably, the molecular sieve membrane is used in series before the molecular sieve.

[0068] According to the present invention, in order to allow the material to flow smoothly through the dewatering device and the dehydration device in sequence, a feed pump can be connected in series before the dewatering device. The feed pump makes the initial pressure before the dewatering and dewatering device greater than 0.1 MPa. Preferably, the feed pump makes the initial pressure before the dewatering and dewatering device 0.2-2 MPa.

[0069] According to the present invention, when the dewatering device includes a molecular sieve membrane, a heater can be connected in series before the molecular sieve membrane to heat the material to 120-200°C to vaporize it, and then the material is fed into the molecular sieve membrane for dewatering.

[0070] According to the present invention, when the dehydration device includes a molecular sieve membrane, a condenser can be connected in series after the molecular sieve membrane to condense the material dehydrated by the molecular sieve membrane to 40-80°C.

[0071] In this invention, the particle removal method can be achieved by using a precision filter, specifically a cartridge filter, with the filter element being a pleated polytetrafluoroethylene (PTFE) material, a pore size of 0.1-0.3 μm, a temperature of 20-55℃, a pressure difference of 0.1-1 MPaG, and a flow rate of 1-8 m³ / s. 3 / (m 2 ·h).

[0072] Using the precision filter described above for departicle removal, particles in crude isopropanol, as well as particles carried out during the deionization and dehydration processes, can be removed, with a particle removal rate of over 99%.

[0073] According to the present invention, the order of dehydration, degranulation and deionization can be adjusted according to product requirements. Dehydration can be performed first, followed by degranulation and deionization to obtain electronic grade isopropanol with lower particle or ion content; or dehydration can be performed last to obtain electronic grade isopropanol with lower water content.

[0074] According to a preferred embodiment of the present invention, deionization, degranulation, and dehydration are performed sequentially, and the water content in the final electronic-grade isopropanol is approximately 24-30 ppm; according to another preferred embodiment of the present invention, dehydration, deionization, and degranulation are performed sequentially, and the metal ion content in the final electronic-grade isopropanol is approximately 0.08-0.11 μg / kg isopropanol; according to another preferred embodiment of the present invention, dehydration, deionization, and degranulation are performed sequentially, and the Cl anion content in the final electronic-grade isopropanol is approximately 40-50 μg / kg isopropanol.

[0075] According to the present invention, the chelating resin, cation exchange resin, anion exchange resin, and molecular sieve all require regeneration before use or after adsorption to saturation. Specifically, the chelating resin and strongly acidic cation exchange resin can be regenerated with 4-6 wt% hydrochloric acid, and the strongly basic anion exchange resin can be regenerated with 4-6 wt% sodium hydroxide. The regeneration method is as follows: the flow rate can be 2-10 BV / h, and the time can be 0.5-3 h, followed by sequential rinsing with water and isopropanol at a flow rate of 2-10 BV / h for 0.1-3 h. The molecular sieve can be regenerated under nitrogen at atmospheric pressure at a flow rate of 100-300 Nm. 3 / (m 3 The temperature can be gradually increased from room temperature to 220-270℃ at a rate of 40-60℃ / h. After the temperature reaches 220-270℃, it should be maintained for 4-20 hours before being cooled by introducing dry air.

[0076] According to a particularly preferred embodiment of the present invention, the method for deionization, dehydration and departicle removal includes: crude isopropanol flowing sequentially through a feed pump, an ion remover, a dehydrator and a precision filter, wherein the ion remover includes a chelating resin column, an acidic cation exchange resin column and a basic anion exchange resin column connected in series, and the dehydrator is a molecular sieve.

[0077] According to a particularly preferred embodiment of the present invention, the deionization, dehydration, and degranulation method includes: crude isopropanol flowing sequentially through a feed pump, an ion remover, a dehydrator, a precision filter, and a booster pump, wherein the ion remover includes a chelating resin column, an acidic cation exchange resin column, and a basic anion exchange resin column connected in series, and the dehydrator includes a molecular sieve membrane and a molecular sieve connected in series.

[0078] According to another particularly preferred embodiment of the present invention, the method of deionization, dehydration and departicle removal includes: crude isopropanol flowing sequentially through a feed pump, a dehydrator, an ion remover and a precision filter, wherein the ion remover includes a chelating resin column, an acidic cation exchange resin column and a basic anion exchange resin column connected in series, and the dehydrator is a molecular sieve.

[0079] According to another particularly preferred embodiment of the present invention, the method for deionization, dehydration, and departicle removal includes: crude isopropanol flowing sequentially through a feed pump, an ion remover, a dehydrator, a precision filter, and a booster pump, wherein the ion remover comprises a basic anion exchange resin column, a chelating resin column, and an acidic cation exchange resin column connected in series, and the dehydrator comprises a molecular sieve membrane and a molecular sieve connected in series. Using the above-described method for dehydration, dehydration, and departicle removal can reduce the anion and cation content, water content, and particle content in electronic-grade isopropanol.

[0080] The present invention will be described in detail below through embodiments.

[0081] Styrene-divinylbenzene polymer microspheres were purchased from Jiangsu Andeli New Material Technology Co., Ltd., with a weight-average molecular weight of 10. 6 g / mol;

[0082] The 3A molecular sieve was purchased from Maclean Company, product number A768497;

[0083] The molecular sieve membrane was purchased from Ningbo Dame Technology Co., Ltd.

[0084] The strongly acidic cation exchange resin was purchased from Tulsimer, Inc., USA, product number T-42.

[0085] The strongly basic anion exchange resin was purchased from Tulsimer Company, USA, catalog number Tulsimer A-23.

[0086] Preparation Example 1

[0087] Imidification reaction: Styrene-divinylbenzene polymerized microspheres were reacted with N-hydroxymethyl phthalimide in 1,2-dichloroethane solvent for 10 h at 80 °C, followed by 5 h at 60 °C. The microspheres were then removed from the solvent, washed with water, and dried to obtain imidized microspheres. The mass ratio of styrene-divinylbenzene polymerized microspheres, N-hydroxymethyl phthalimide, and solvent was 1:1.2:18.

[0088] Alkaline hydrolysis reaction: The dried imidized microspheres were reacted in an alkaline aqueous solution (5 wt% sodium hydroxide aqueous solution) for 10 h at a reaction temperature of 40 °C. After the reaction was completed, the microspheres were washed with water and dried. The amount of sodium hydroxide used was 1.43 g per gram of styrene-divinylbenzene polymerized microspheres.

[0089] Carboxylation reaction: 35g of hydrolyzed microspheres were placed in 800ml of sodium acetate aqueous solution (sodium acetate content was 10wt%), and reacted at 60℃ for 10h, and then reacted at 80℃ for 2h.

[0090] Resin post-treatment: The above microspheres were washed with water (pure water), acid washed (5wt% HCl solution), and washed with water (pure water) until neutral, and then dried to obtain chelating resin.

[0091] The average particle size of the chelating resin was measured to be 815 μm.

[0092] Preparation Example 2

[0093] Imidification reaction: Styrene-divinylbenzene polymer microspheres were reacted with N-hydroxymethyl phthalimide in 1,2-dichloroethane solvent for 10 h at 80 °C, followed by 5 h at 60 °C. The microspheres were then removed from the solvent, washed with water, and dried to obtain imidized microspheres. The mass ratio of styrene-divinylbenzene polymer microspheres, N-hydroxymethyl phthalimide, and solvent was 1:1.5:25.

[0094] Alkaline hydrolysis reaction: The dried imidized microspheres were reacted in an alkaline aqueous solution (10 wt% sodium hydroxide aqueous solution) for 10 h at a reaction temperature of 40 °C. After the reaction was completed, the microspheres were washed with water and dried to obtain hydrolyzed microspheres. The amount of sodium hydroxide used was 2.86 g relative to each gram of styrene-divinylbenzene polymerized microspheres.

[0095] Carboxylation reaction: 35g of hydrolyzed microspheres were placed in 800ml of sodium acetate aqueous solution (sodium acetate content was 15wt%) and reacted at 60℃ for 10h, and then reacted at 80℃ for 2h.

[0096] Resin post-treatment: The above microspheres were washed with water (pure water), acid washed (10wt% HCl solution), and washed with water (pure water) until neutral, and then dried to obtain chelating resin.

[0097] The average particle size of the chelating resin was measured to be 822 μm.

[0098] Example 1

[0099] The preparation system for electronic-grade isopropanol mainly includes a reaction unit, a distillation unit, and a purification unit connected in series.

[0100] The purification unit includes a feed pump, nanofiltration membrane, ion remover, dehydrator, and precision filter connected in series. Crude isopropanol is pressurized to 1.0 MPaG by the feed pump and then flows sequentially through the other devices to obtain electronic-grade isopropanol. The compositions of crude isopropanol and electronic-grade isopropanol were determined using gas chromatography and ICP, as shown in Table 1.

[0101] The nanofiltration membrane used is a polyethersulfone nanofiltration membrane with a molecular weight cutoff (MWCO) of 150 g / mol. The inlet pressure is 1.0 MPaG and the outlet pressure is 0.8 MPaG. It removes some metal ions from the feedstock, yielding a nanofiltration solution and a nanofiltration concentrate. The nanofiltration concentrate can be used as non-electronic grade isopropanol, and the nanofiltration solution is further purified.

[0102] Ion remover: consists of a chelating resin column, a strongly acidic cation exchange resin column, and a strongly basic anion exchange resin column connected in series. All three columns have a diameter of 500 mm, a height of 1750 mm, a resin packing volume of 1000 mm, a flow rate of 10 BV / h, and inlet pressures of 0.8, 0.75, and 0.7 MPaG, respectively.

[0103] The chelating resin column was filled with the chelating resin prepared in Preparation Example 1. The main structure was a cross-linked copolymer with iminodiacetic acid as the main functional group. It was amber-colored, moist spherical with an average particle size of 1 mm.

[0104] The main structure of the strongly acidic cation exchange resin is a cross-linked copolymer, with the main functional group being a nucleo-grade sulfonic acid group. It is an amber-colored, moist spherical resin with an average particle size of 0.8 mm.

[0105] The main structure of the strongly basic anion exchange resin is a cross-linked copolymer, with the main functional group being quaternary ammonium functional group. It is a pale yellow, moist spherical resin with an average particle size of 0.8 mm.

[0106] The resin in the ion remover needs to be regenerated after initial use or after reaching saturation adsorption capacity to remove adsorbed metal ions and anions. Chelating resins and strongly acidic ion exchange resins are regenerated with 5 wt% hydrochloric acid, while strongly basic ion exchange resins are regenerated with 5 wt% sodium hydroxide. The regeneration method is as follows: flow rate 5 BV / h, time 1 h, followed by sequential rinsing with water (purified water) and isopropanol at a flow rate of 5 BV / h for 0.5 h.

[0107] A fixed-bed dewatering unit filled with molecular sieves was selected. The fixed-bed dewatering unit has a diameter of 500 mm and a height of 1500 mm. The molecular sieve is 3A molecular sieve, and the filling height is 1000 mm. After the molecular sieve has adsorbed to its saturation capacity, it needs to be regenerated in nitrogen at atmospheric pressure at a flow rate of 150 Nm. 3 / (m 3 The temperature is gradually increased from room temperature to 250℃ at a rate of 50℃ / h. After the temperature reaches 250℃, it is maintained for 12 hours, and then dry nitrogen is introduced to cool it down.

[0108] The precision filter uses a cartridge filter, with the cartridge being a pleated polytetrafluoroethylene (PTFE) material. The flow rate per square meter of the cartridge is 4 m / s. 3 / (m 2 The filter pore size is 0.2 μm and the operating pressure is 0.65 MPaG.

[0109] Except for the regeneration of molecular sieves, the temperature of all other equipment and operations is 25°C.

[0110] Example 2

[0111] The purification unit includes a feed pump, an ion remover, a dehydrator, a precision filter, and a booster pump connected in series. Crude isopropanol is pressurized to 0.3 MPaG by the feed pump and then sequentially flows through the other devices to obtain electronic-grade isopropanol. The compositions of crude isopropanol and electronic-grade isopropanol were determined using gas chromatography and ICP, as shown in Table 1.

[0112] Ion remover: It consists of a chelating resin column, a strong acid cation exchange resin column, and a strong base anion exchange resin column connected in series. All three columns have a diameter of 500 mm, a height of 1750 mm, a resin packing volume of 1000 mm, a flow rate of 11 BV / h, and inlet pressures of 0.3, 0.25, and 0.2 MPaG, respectively.

[0113] The chelating resin column was filled with the chelating resin prepared in Preparation Example 1, the main structure of which was a cross-linked copolymer.

[0114] The main structure of the strongly acidic cation exchange resin is a cross-linked copolymer, with the main functional group being a nucleo-grade sulfonic acid group. It is an amber-colored, moist spherical resin with an average particle size of 0.75 mm.

[0115] The main structure of the strongly basic anion exchange resin is a cross-linked copolymer, with the main functional group being quaternary ammonium functional group. It is a pale yellow, moist spherical resin with an average particle size of 0.75 mm.

[0116] The resin in the ion remover needs to be regenerated after initial use or after reaching saturation adsorption capacity to remove adsorbed metal ions and anions. Specifically, chelating resin and strongly acidic cation exchange resin are regenerated with 5 wt% hydrochloric acid, while strongly basic anion exchange resin is regenerated with 5 wt% sodium hydroxide. The regeneration method is as follows: flow rate of 5 BV / h, time of 1 h, followed by sequential rinsing with water (purified water) and isopropanol at a flow rate of 5 BV / h for 0.5 h.

[0117] The dewatering unit is a hybrid dewatering unit consisting of a molecular sieve membrane and a fixed-bed dewatering unit packed with molecular sieves connected in series. The fixed-bed dewatering unit has a diameter of 500 mm and a height of 1500 mm. The molecular sieve is a 3A molecular sieve with a packing height of 1000 mm. The molecular sieve membrane is a NaA type inorganic molecular sieve pervaporation membrane.

[0118] After the molecular sieve adsorbs to its saturation capacity, it needs to be regenerated in nitrogen gas at atmospheric pressure with a flow rate of 150 Nm. 3 / (m 3 The temperature is gradually increased from room temperature to 250℃ at a rate of 50℃ / h. After the temperature reaches 250℃, it is maintained for 12 hours, and then dry nitrogen is introduced to cool it down.

[0119] The material flowing out of the ion remover is heated to 150°C in the heater and then vaporized before being sent to the molecular sieve membrane module for separation and dehydration. The dehydrated product is condensed to 40°C by the condenser and then sent to the molecular sieve fixed bed dehydrator.

[0120] The precision filter uses a cartridge filter, with the cartridge being a pleated polytetrafluoroethylene (PTFE) material, and a flow rate of 3.5m / s. 3 / (m 2 The filter pore size is 0.2 μm and the operating pressure is 0.15 MPaG.

[0121] A booster pump installed at the material outlet ensures that the operating pressure of the chelating resin column is 0.3 MPaG.

[0122] Except for the regeneration of molecular sieves, the temperature for all other equipment and operations is 25°C.

[0123] Example 3

[0124] The procedure was followed according to Example 2, except that the order of the chelating resin column, acidic cation exchange resin column, and basic anion exchange resin column was reversed to that of basic anion exchange resin column, chelating resin column, and acidic cation exchange resin column. The composition of the obtained electronic-grade isopropanol is shown in Table 1.

[0125] Example 4

[0126] Following the method of Example 2, except that the dehydration process was adjusted to occur before ion removal, the composition of the obtained electronic-grade isopropanol is shown in Table 1.

[0127] Example 5

[0128] The procedure was followed as in Example 2, except that the chelating resin in the chelating resin column was the chelating resin prepared in Preparation Example 2.

[0129] Comparative Example 1

[0130] Following the method of Example 2, except that the chelating resin was replaced with an equal amount of other chelating resins (manufacturer: Mitsubishi, Japan, product number DIAION CR20), the composition of the electronic grade isopropanol obtained is shown in Table 2.

[0131] Comparative Example 2

[0132] The procedure was followed according to Example 2, except that the chelating resin was replaced with an equal amount of the acidic cation exchange resin column used in Example 1. The composition of the electronic grade isopropanol obtained is shown in Table 2.

[0133] Comparative Example 3

[0134] Following the method of Example 2, except that the chelating resin was replaced with an acidic cation exchange resin column (manufacturer: Kehaisi (Beijing) Technology Co., Ltd., CH-97) with half the amount of the original chelating resin and an alkaline anion exchange resin column (manufacturer: Dusheng, USA, CXO-12) with half the amount of the original chelating resin, the composition of the obtained electronic grade isopropanol is shown in Table 2.

[0135] Table 1

[0136]

[0137] Table 2

[0138]

[0139] As shown in Tables 1-2, the chelating resin prepared by the method provided in this invention can significantly reduce the proportion of metal ions in electronic grade isopropanol and improve the quality of electronic grade isopropanol; the molecular sieve membrane can reduce the water content in electronic grade isopropanol.

[0140] In Example 1, the molecular sieve needed to be regenerated once for every 4800 kg of electronic-grade isopropanol produced; the acidic cation exchange resin needed to be regenerated once for every 50400 kg of electronic-grade isopropanol produced. In Example 2, the molecular sieve only needed to be regenerated once for every 48000 kg of electronic-grade isopropanol produced. In Comparative Examples 2 and 3, the first acidic cation exchange resin needed to be regenerated once for every 25200 kg of electronic-grade isopropanol produced. It can be seen that by increasing the number of regenerations of the molecular sieve and acidic cation exchange resin column, the number of regenerations of the molecular sieve and acidic cation exchange resin can be significantly reduced, simplifying the production process and lowering production costs.

[0141] 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 inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. 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 a chelating resin, the method comprising: Styrene-divinylbenzene polymer microspheres were contacted with N-hydroxymethyl phthalimide, and imidization, hydrolysis, and carboxylation reactions were carried out sequentially.

2. The method according to claim 1, wherein, In the styrene-divinylbenzene polymer microspheres, the molar ratio of structural units provided by styrene to structural units provided by divinylbenzene is (2-30):1; And / or, the average particle size of the styrene-divinylbenzene polymer microspheres is 200-1000 μm; And / or, the weight-average molecular weight of the styrene-divinylbenzene polymeric microspheres is 10. 5 -10 8 g / mol; And / or, the imidization reaction method includes: in the presence of a solvent, contacting styrene-divinylene polymer microspheres with N-hydroxymethyl phthalimide and sequentially performing a first imidization and a second imidization to obtain imidized microspheres, wherein the temperature of the first imidization is 10-30°C higher than that of the second imidization; Preferably, the mass ratio of styrene-diethylene polymer microspheres, N-hydroxymethyl phthalimide and solvent is 1:(1-5):(5-50), more preferably 1:(1-1.5):(15-20); Preferably, the solvent is at least one selected from 1,2-dichloroethane, carbon tetrachloride, and toluene, and more preferably 1,2-dichloroethane; And / or, the method of the hydrolysis reaction includes: hydrolyzing the imidized microspheres in the presence of an alkaline substance to obtain hydrolyzed microspheres; Preferably, the amount of alkaline substance used is 1-15 grams per gram of styrene-divinylbenzene polymer microspheres; Preferably, the alkaline substance is at least one selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide, and more preferably sodium hydroxide; And / or, the hydrolysis reaction is carried out by placing the imidized microspheres in an alkaline solution containing an alkaline substance for hydrolysis, wherein the content of the alkaline substance in the alkaline solution is 2-30 wt%. And / or, the method of the carboxylation reaction includes: contacting hydrolyzed microspheres with acetate to perform a first carboxylation and a second carboxylation to obtain carboxylated microspheres, wherein the temperature of the first carboxylation is 10-30°C lower than that of the second carboxylation; Preferably, the acetate is used in the form of an acetate solution, wherein the acetate content in the acetate solution is 5-30 wt%. Preferably, the mass ratio of the acetate to the hydrolyzed microspheres is (0.5-15):1; Preferably, the acetate is at least one of sodium acetate, potassium acetate, and ammonium acetate, and more preferably sodium acetate.

3. The method according to claim 2, wherein, The reaction conditions for the first imidization include: a temperature of 75-85℃ and a time of 2-20h; And / or, the reaction conditions for the second iminolation include: a temperature of 55-65°C and a time of 0.5-20 h; And / or, the reaction conditions for the hydrolysis reaction include: a temperature of 35-45℃ and a reaction time of 2-20h; And / or, the reaction conditions for the first carboxylation include: a temperature of 55-65°C and a time of 1-20 h; And / or, the reaction conditions for the second carboxylation include: a temperature of 75-85°C and a time of 1-20 h.

4. The method according to claim 2, wherein, The method further includes washing with water and drying after the imidization reaction and the hydrolysis reaction, respectively; And / or, after the carboxylation reaction, the mixture is washed with water, acid-washed, and dried, wherein the acid-washing liquid is an acidic aqueous solution, preferably a 3-10 wt% HCl aqueous solution.

5. The chelating resin prepared by the method according to any one of claims 1-4, wherein, The chelating resin comprises polymer microspheres and modifying groups on the surface of the polymer microspheres, wherein the polymer microspheres are styrene-divinylbenzene polymer microspheres, and the structure of the modifying groups is shown in Formula 1 below.

6. A method for preparing electronic-grade isopropanol, characterized in that, The method includes: deionizing, dehydrating and degranulating the crude isopropanol product; The method of deionization includes column chromatography of crude isopropanol through a chelating resin column, an acidic cation exchange resin column, and a basic anion exchange resin column; the resin of the chelating resin column is a chelating resin prepared by the method described in claims 1-4 or a chelating resin described in claim 5.

7. The method according to claim 6, wherein, The method of deionization also includes nanofiltration membrane filtration; Preferably, the nanofiltration membrane used for the nanofiltration is a polyethersulfone nanofiltration membrane; Preferably, the nanofiltration membrane used for nanofiltration has a molecular weight cutoff of 120-210 kg / kmol; Preferably, the conditions for nanofiltration include: a temperature of 25-50°C and a pressure difference of 0.1-0.3 MPa.

8. The method according to claim 6, wherein, The average particle size of the resin in the chelating resin column is 0.4-1.2 mm; Preferably, the operating conditions of the chelating resin column include: a temperature of 20-55℃, a pressure difference of 0.01-0.1MPaG, and a flow rate of 8-12 BV / h; And / or, the average particle size of the acidic cation exchange resin column is 0.4-1.2 mm; Preferably, the operating conditions of the acidic cation exchange resin column include: a temperature of 20-55℃, a pressure difference of 0.01-0.1 MPaG, and a flow rate of 8-12 BV / h; And / or, the average particle size of the basic anion exchange resin column is 0.3-1.2 mm; Preferably, the operating conditions of the basic anion exchange resin column include: a temperature of 20-55℃, a pressure difference of 0.01-0.1MPaG, and a flow rate of 8-12 BV / h.

9. The method according to claim 6, wherein, The dehydration method is molecular sieve dehydration, preferably, at least one of molecular sieve and molecular sieve membrane is used for dehydration; Preferably, the molecular sieve is at least one of type X molecular sieve and type A molecular sieve, preferably 1240492. I96422BHY 3A molecular sieve; Preferably, the molecular sieve membrane is at least one of NaA-type inorganic molecular sieve pervaporation membrane, polyvinyl alcohol pervaporation membrane, and polyimide pervaporation membrane, and more preferably a NaA-type inorganic molecular sieve pervaporation membrane.

10. The method according to any one of claims 6-9, wherein, The particle removal method involves filtration using a precision filter, specifically a cartridge filter with a pleated PTFE filter element. The temperature range is 20-55℃, the pressure difference is 0.1-1 MPaG, and the flow rate is 1-8 m³ / s. 3 / (m 2 ·h).

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