Preparation method of ultrahigh-purity isopropanol

Abstract

The application provides a preparation method of ultrahigh-purity isopropyl alcohol, which comprises the following steps: (1) vacuum rectification; (2) atmospheric rectification; (3) ion exchange: isopropyl alcohol obtained in step (2) is subjected to ion exchange mixed material to obtain the ultrahigh-purity isopropyl alcohol; the ion exchange mixed material comprises cation exchange material and anion exchange material, the exchange functional group of the cation exchange material comprises sulfonic acid group, and the exchange functional group of the anion exchange material comprises amine group. The preparation method can efficiently and quickly remove residual metal ions in isopropyl alcohol, so that the content of each metal ion is less than 0.01 ppb, meets the SEMI Grade 5 standard, and the content of isopropyl alcohol is greater than 99.999%, and is generally applicable to cleaning and drying of semiconductors and integrated circuits. In addition, the preparation method is suitable for industrialized continuous production, and will promote the development of the integrated circuit industry to higher nanometer process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor technology, and particularly relates to a preparation method of super-high-purity isopropyl alcohol. BACKGROUND

[0002] With the rapid development of semiconductor technology, the requirements for super-high-purity reagents are higher and higher. In the processing of integrated circuits (IC), super-high-purity reagents are mainly used for cleaning and etching the surface of chips and silicon circles, and the purity and cleanliness of the super-high-purity reagents have a very significant influence on the yield, performance and reliability of integrated circuits. As an important microelectronic chemical, super-high-purity isopropyl alcohol has been widely used in cleaning, drying and other aspects in the processing of semiconductors and large-scale integrated circuits.

[0003] In addition, the integrated circuit industry has very strict requirements for the content of trace metal element impurities in high-purity chemical reagents. In 1975, the Semiconductor Equipment and Materials International (SEMI) established a SEMI Chemical Standardization Committee to formulate and standardize international unified standards for high-purity chemical reagents. The purity of high-purity chemical reagents is closely related to the line width of integrated circuits. The narrower the line width of integrated circuits, the lower the content of metal impurities in the solvents required.

[0004] In recent years, with the development of the information industry, the line width of integrated circuits is continuously challenging the limit, and the most advanced integrated circuit mass production process in the world has reached below 5nm, and the metal impurity content of the super-pure isopropyl alcohol required must be controlled within 10ppt (SEMI, Grand 5 level).

[0005] Chinese patent application CN 106748652A discloses a method for removing trace metal impurities in industrial-grade isopropyl alcohol, which uses modified cellulose as an adsorbent combined with a cation exchange resin, and the obtained isopropyl alcohol has a metal main impurity ion content of 0.02-0.1ppb, which fails to meet the Grand 5 level metal impurity requirement, and the content of isopropyl alcohol is not mentioned.

[0006] Chinese patent CN 101362675B discloses a preparation method and device of super-clean high-purity isopropyl alcohol, which includes the steps of dehydration, filtration, four-stage rectification, purification, nanofiltration and the like. The process is complicated and energy-consuming, and the obtained product has a main body content of isopropyl alcohol of 99.99%, and a single cation content of 0.03-0.1ppb, which still fails to meet the Grand 5 level metal impurity requirement.

[0007] Chinese patent CN 102898275 B discloses a preparation method of high-purity isopropanol, the prepared high-quality electronic-grade isopropanol has a concentration of 1-115 ppt for each single cation, and the ion quality is unstable. The preparation method comprises steps of dehydration, reverse osmosis, rectification, ion exchange, and circulation filtration, and the process is complicated. The content of isopropanol is not mentioned.

[0008] In summary, there is still lack of an effective method for realizing that the content of each metal impurity in the ultrahigh-purity isopropanol is less than 0.01 ppb and the content of isopropanol is greater than 99.999%. Therefore, it is very important to develop a purification method of ultrahigh-purity isopropanol which is simple to operate and stable in quality, so as to match the process technology of integrated circuits with a line width of less than 5 nm. SUMMARY

[0009] Based on this, the purpose of the present application is to provide a preparation method of ultrahigh-purity isopropanol, which is simple to operate, and the content of each metal ion in the prepared isopropanol is less than 0.01 ppb, meeting the SEMI Grade 5 standard.

[0010] To achieve the above-mentioned purpose, the present application adopts the following technical solutions.

[0011] A preparation method of ultrahigh-purity isopropanol comprises the following steps: (1) vacuum rectification: industrial-grade isopropanol is subjected to vacuum rectification under the conditions that the temperature is 10-60 ℃, the vacuum degree is 50-100 kPa, and the reflux ratio is 1-5; (2) atmospheric rectification: the isopropanol obtained in step (1) is subjected to atmospheric rectification under the conditions that the temperature is 80-95 ℃ and the reflux ratio is 1-5; (3) ion exchange: the isopropanol obtained in step (2) is subjected to ion exchange through ion exchange mixed materials to obtain the ultrahigh-purity isopropanol; the ion exchange mixed materials comprise cation exchange materials and anion exchange materials, the exchange functional groups of the cation exchange materials comprise sulfonic acid groups, and the exchange functional groups of the anion exchange materials comprise amine groups.

[0012] In some embodiments, the ion molar amount of the cation exchange materials in the ion exchange mixed materials per unit volume that can be subjected to ion exchange is 1.5-3.0 mol / ml.

[0013] In some preferred embodiments, the ion molar amount of the cation exchange materials in the ion exchange mixed materials per unit volume that can be subjected to ion exchange is 1.5-2.5 mol / ml.

[0014] In some embodiments, the amine groups are selected from at least one of primary amine groups, secondary amine groups, and tertiary amine groups.

[0015] In some embodiments, the cation exchange materials are selected from at least one of cation exchange resins and cation exchange membranes.

[0016] In some preferred embodiments, the cation exchange material is selected from at least one of polystyrene cation exchange resin having sulfonic acid group, polypropylene cation exchange resin having sulfonic acid group, nylon-66 cation membrane having sulfonic acid group, and polyphenylsulfone cation membrane having sulfonic acid group.

[0017] In some embodiments, the anion exchange material is selected from at least one of anion exchange resin, anion exchange membrane.

[0018] In some preferred embodiments, the anion exchange material is selected from at least one of polystyrene anion exchange resin having primary amine group, polypropylene anion exchange resin having secondary amine group, nylon-66 anion membrane having tertiary amine group, polyphenylsulfone anion membrane having primary amine group, and polyphenylsulfone anion membrane having secondary amine group.

[0019] In some embodiments, the industrial-grade isopropyl alcohol contains at least one of lithium ion, beryllium ion, sodium ion, magnesium ion, aluminum ion, potassium ion, calcium ion, titanium ion, vanadium ion, chromium ion, manganese ion, iron ion, cobalt ion, nickel ion, copper ion, zinc ion, gallium ion, germanium ion, strontium ion, zirconium ion, niobium ion, molybdenum ion, palladium ion, silver ion, indium ion, tin ion, antimony ion, barium ion, tantalum ion, tungsten ion, platinum ion, gold ion, thallium ion, lead ion, and bismuth ion. The content of the various metal ions in the industrial-grade isopropyl alcohol is 5 ppb or less.

[0020] In some embodiments, the step (1) is performed under the conditions of a temperature of 20-40°C, a vacuum degree of 60-80 kPa, and a reflux ratio of 2-4.

[0021] In some embodiments, the step (2) is performed under the conditions of a temperature of 85-95°C and a reflux ratio of 1-3.

[0022] The present application provides a simple and efficient method for preparing ultra-high purity isopropanol, which comprises subjecting industrial grade isopropanol to vacuum rectification, atmospheric rectification and ion exchange treatment in sequence. The inventors have found, based on their own experience and a large number of researches, that the industrial grade isopropanol can remove water and other impurities and most of the metal ions after being subjected to the vacuum rectification and atmospheric rectification of the present application, and further treatment with the optimized ion exchange mixed material of the present application, which comprises a cation exchange material containing sulfonic acid groups and an anion exchange material containing amine groups, can efficiently and quickly remove other residual metal ions without introducing other ions. Thus, the content of each metal ion in the ultra-high purity isopropanol prepared by the present application is less than 0.01 ppb, which meets the SEMI Grade 5 standard, and the content of isopropanol is greater than 99.999%, which is generally applicable to cleaning and drying of semiconductors and integrated circuits. Further, the inventors have found that the volume exchange flux of the ion exchange mixed material affects the purification effect, and satisfactory results can be obtained when the volume exchange flux is 1.5-3.0 mol / ml, and the effect is even better when the volume exchange flux is 1.5-2.5 mol / ml.

[0023] The preparation method of the present application is simple in operation and stable in product quality, and is suitable for industrialized continuous production, which will promote the development of the integrated circuit industry to higher nanometer process. DETAILED DESCRIPTION

[0024] The experimental methods not specified in the following examples of the present application are generally carried out under conventional conditions or under the conditions recommended by the manufacturers. The various common chemical reagents used in the examples are commercially available products.

[0025] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0026] The terms "comprising" and "having" and any variations thereof in the present application are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment comprising a series of steps is not limited to the listed steps or modules, but can optionally further comprise steps not listed, or can optionally further comprise other steps inherent to the process, method, product or equipment.

[0027] In the present application, "a plurality of" means two or more. "And / or", which describes the association relationship of the associated objects, means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. The character " / " generally represents that the associated objects before and after it are in an "or" relationship.

[0028] The present embodiment provides a method for preparing ultra-high purity isopropanol, which comprises the following steps: (1) vacuum rectification: industrial grade isopropanol is subjected to vacuum rectification under the conditions of a temperature of 10-60°C, a vacuum degree of 50-100 kPa, and a reflux ratio of 1-5, and isopropanol is collected from the bottom of the column; (2) atmospheric rectification: isopropanol obtained in step (1) is subjected to atmospheric rectification under the conditions of a temperature of 80-95°C and a reflux ratio of 1-5, and isopropanol is collected from the top of the column; (3) ion exchange: isopropanol obtained in step (2) is passed through ion exchange mixed materials to obtain the ultra-high purity isopropanol; the ion exchange mixed materials comprise cation exchange materials and anion exchange materials, the exchange functional groups of the cation exchange materials comprise sulfonic acid groups, and the exchange functional groups of the anion exchange materials comprise amine groups.

[0029] In some embodiments, the amine groups are selected from at least one of primary amine groups, secondary amine groups, and tertiary amine groups. The amine groups are used to balance the solution potential.

[0030] In some embodiments, the ion exchange mixed materials are selected from at least one of the following mixed materials: mixed materials of polystyrene cation exchange resins with sulfonic acid groups and polystyrene anion exchange resins with primary amine groups; mixed materials of polypropylene cation exchange resins with sulfonic acid groups and polypropylene anion exchange resins with secondary amine groups; mixed materials of nylon-66 cation membranes with sulfonic acid groups and nylon-66 anion membranes with tertiary amine groups; mixed materials of polyphenylsulfone cation membranes with sulfonic acid groups, polyphenylsulfone anion membranes with primary amine groups, and polyphenylsulfone anion membranes with secondary amine groups.

[0031] The ion exchange mixed materials of the present embodiment comprise cation exchange materials and anion exchange materials. When the ion exchange mixed materials comprise cation exchange resins and anion exchange resins, the cation exchange resins and the anion exchange resins are mixed to obtain the ion exchange mixed materials; at this time, isopropanol collected from the top of the column in the atmospheric rectification step is passed through the ion exchange mixed materials to obtain the ultra-high purity isopropanol. When the ion exchange mixed materials comprise cation exchange membranes and anion exchange membranes, or cation exchange membranes and anion exchange resins, or cation exchange resins and anion exchange membranes, isopropanol collected from the top of the column in the atmospheric rectification step is sequentially passed through the cation exchange membranes and the anion exchange membranes, or sequentially passed through the cation exchange membranes and the anion exchange resins, or sequentially passed through the cation exchange resins and the anion exchange membranes to obtain the ultra-high purity isopropanol.

[0032] The ion exchange mixed material provides only hydrogen ions and hydroxyl ions for exchange, wherein the sulfonic acid group exchange material provides hydrogen ions and the amine group exchange material provides hydroxyl ions. The ion exchange mixed material comprises a cation exchange material and an anion exchange material, and the cation exchange material and the anion exchange material can be subjected to pretreatment steps such as activation and regeneration according to conventional means in the art before use. For example, the pretreatment can be performed by treating the cation exchange material with 3% hydrochloric acid and treating the anion exchange material with 3% sodium hydroxide. After the above pretreatment, the cation exchange material binds hydrogen ions and the anion exchange material binds hydroxyl ions. The inventors have found through extensive research that when the exchange functional groups of the cation exchange material comprise sulfonic acid groups and the exchange functional groups of the anion exchange material comprise amine groups, 100% exchange of hydrogen ions / hydroxyl ions can be achieved in the pretreatment stage. If a cation exchange material containing other acidic groups is used, 100% exchange of hydrogen ions cannot be achieved in the pretreatment stage, leaving other cations such as sodium ions, iron ions, etc., which may pose a risk in the subsequent treatment of isopropyl alcohol. The same applies to the selection of amine groups. If an anion exchange material containing other anionic groups is used, 100% exchange of hydroxyl ions cannot be achieved, leaving other anions such as chloride ions. Thus, there is a high risk of residual HCl in the solution. At this time, there is an equilibrium between hydrogen ions and part of the cations, resulting in the inability to remove part of the cations.

[0033] The volume exchange flux of the ion exchange mixed material (i.e. the ion molar amount of ion exchange that can be performed by the cation exchange material per unit volume of the ion exchange mixed material) affects the purification effect, and insufficient exchange flux leads to increased energy consumption.

[0034] In some embodiments, the volume exchange flux of the ion exchange mixed material is 1.5-3.0 mol / ml; preferably 1.5-2.5 mol / ml.

[0035] Specifically, the volume exchange flux of the ion exchange mixed material is 1.2 mol / ml, 1.5 mol / ml, 1.7 mol / ml, 1.9 mol / ml, 2.0 mol / ml, 2.2 mol / ml, 2.5 mol / ml, 2.75 mol / ml, or 3 mol / ml.

[0036] In some embodiments, the industrial-grade isopropyl alcohol is an industrial-grade isopropyl alcohol meeting the requirements of GB 7814-2017.

[0037] In some embodiments, the metal ion content detection method is as follows: quantitative analysis is performed using inductively coupled plasma mass spectrometry (ICP-MS) (manufactured by Agilent, Agilent 8900 ICP-MS).

[0038] In some embodiments, the isopropanol content detection method is as follows: quantitative analysis is performed using a gas chromatograph (GC) (manufactured by Agilent, Agilent 7890B GC).

[0039] The following will be described in conjunction with specific embodiments.

[0040] Embodiment 1

[0041] The embodiment provides a preparation method of ultrahigh-purity isopropanol, which comprises the following steps:

[0042] First, 99.7% industrial-grade isopropanol is subjected to vacuum rectification: the heating temperature of the column bottom is controlled at 20°C, the vacuum degree is 80 kPa, and the reflux ratio is 2, and isopropanol is collected from the bottom of the column; then subjected to atmospheric rectification: the heating temperature of the column bottom is controlled at 85°C, and the reflux ratio is 1, and isopropanol is collected from the top of the column; finally, ion exchange: isopropanol is passed through an ion exchange mixed material of polystyrene cation exchange resin with sulfonic acid group and polystyrene anion exchange resin with primary amine group, and the volume exchange flux is 1.5 mol / ml, to obtain ultrahigh-purity isopropanol.

[0043] It is detected that the content of isopropanol in the ultrahigh-purity isopropanol is 99.9993%. The content of each metal ion in isopropanol before and after treatment is shown in Table 1.

[0044] Table 1: Content detection results of each metal ion impurity in ultrahigh-purity isopropanol

[0045]

[0046]

[0047]

[0048] As can be seen from Table 1, the content of each metal ion impurity in the ultrahigh-purity isopropanol prepared in this embodiment is less than 0.01 ppb, which meets the SEMI Grade 5 standard.

[0049] Embodiment 2

[0050] The embodiment provides a preparation method of ultrahigh-purity isopropanol, which comprises the following steps:

[0051] The 99.8% industrial grade isopropanol was first subjected to vacuum rectification: the heating temperature of the column bottom was controlled at 30°C, the vacuum degree was 70 kPa, and the reflux ratio was 3, and the isopropanol was collected from the bottom; then subjected to atmospheric rectification: the heating temperature of the column bottom was controlled at 90°C, and the reflux ratio was 2, and the isopropanol was collected from the top; finally subjected to ion exchange: the isopropanol was passed through an ion exchange mixed material with a volume exchange flux of 2.0 mol / ml of a nylon-66 positive membrane with sulfonic acid groups and a nylon-66 negative membrane with tertiary amine groups to obtain super-high-purity isopropanol.

[0052] It was detected that the content of isopropanol in the super-high-purity isopropanol was 99.9991%. The content of each metal ion in isopropanol before and after treatment is shown in Table 2.

[0053] Table 2 Detection results of the content of each metal ion impurity in super-high-purity isopropanol

[0054]

[0055]

[0056] As shown in Table 2, the content of each metal ion impurity in the super-high-purity isopropanol prepared in this embodiment was less than 0.01 ppb, which met the SEMI Grade 5 standard.

[0057] Example 3

[0058] This embodiment provides a preparation method of super-high-purity isopropanol, which comprises the following steps:

[0059] The 99.9% industrial grade isopropanol was first subjected to vacuum rectification: the heating temperature of the column bottom was controlled at 40°C, the vacuum degree was 60 kPa, and the reflux ratio was 4, and the isopropanol was collected from the bottom; then subjected to atmospheric rectification: the heating temperature of the column bottom was controlled at 95°C, and the reflux ratio was 3, and the isopropanol was collected from the top; finally subjected to ion exchange: the isopropanol was passed through an ion exchange mixed material with a volume exchange flux of 2.5 mol / ml of a polyphenylsulfone positive membrane with sulfonic acid groups, a polyphenylsulfone negative membrane with primary amine groups, and a polyphenylsulfone negative membrane with secondary amine groups to obtain super-high-purity isopropanol.

[0060] It was detected that the content of isopropanol in the super-high-purity isopropanol was 99.9993%. The content of each metal ion in isopropanol before and after treatment is shown in Table 3.

[0061] Table 3 Detection results of the content of each metal ion impurity in super-high-purity isopropanol

[0062]

[0063]

[0064] From Table 4, it can be seen that the content of each metal ion impurity in the ultra-high purity isopropanol prepared in this embodiment is less than 0.01 ppb, meeting the SEMI Grade 5 standard. However, due to the insufficient exchange flux of the ion exchange mixed material, it is necessary to ionize twice to obtain the effect that the content of each metal ion impurity is less than 0.01 ppb.

[0065] Example 4

[0066] This embodiment provides a preparation method of ultra-high purity isopropanol. Except that the volume exchange flux of the ion exchange mixed material is different, the source of industrial grade isopropanol and other treatment steps are the same as those in Example 1, and the specific steps are as follows:

[0067] First, 99.7% industrial grade isopropanol is subjected to vacuum rectification: the heating temperature of the column bottom is controlled at 20℃, the vacuum degree is 80kPa, and the reflux ratio is 2, and isopropanol is collected from the bottom of the column; then subjected to atmospheric distillation: the heating temperature of the column bottom is controlled at 85℃, the reflux ratio is 1, and isopropanol is collected from the top of the column; finally, ion exchange is performed, and the isopropanol is passed through an ion exchange mixed material of polystyrene cation exchange resin with sulfonic acid group and polystyrene anion exchange resin with primary amine group with a volume exchange flux of 1.2mol / ml, and the treatment is repeated twice to obtain ultra-high purity isopropanol.

[0068] It is detected that the content of isopropanol in the ultra-high purity isopropanol is 99.9991%. The content of each metal ion in isopropanol before and after treatment is shown in Table 4.

[0069] Table 4: Content detection results of each metal ion impurity in ultra-high purity isopropanol

[0070]

[0071]

[0072]

[0073] From Table 4, it can be seen that the content of each metal ion impurity in the ultra-high purity isopropanol prepared in this embodiment is less than 0.01 ppb, meeting the SEMI Grade 5 standard. However, due to the insufficient exchange flux of the ion exchange mixed material, it is necessary to ionize twice to obtain the effect that the content of each metal ion impurity is less than 0.01 ppb.

[0074] Comparative Example 1

[0075] This comparative example provides a preparation method of ultra-high purity isopropanol. Except that the ion exchange material used in the ion exchange step is different, the source of industrial grade isopropanol and other treatment steps are the same as those in Example 1, and the specific steps are as follows:

[0076] The 99.7% industrial grade isopropanol was first subjected to vacuum rectification: the heating temperature of the column bottom was controlled at 20°C, the vacuum degree was 80 kPa, and the reflux ratio was 2, and isopropanol was collected from the bottom of the column; then subjected to atmospheric rectification: the heating temperature of the column bottom was controlled at 85°C, the reflux ratio was 1, and isopropanol was collected from the top of the column; finally subjected to ion exchange: the isopropanol was passed through a polystyrene cation exchange resin with a sulfonic group with a volume exchange flux of 1.5 mol / ml to obtain ultra-high purity isopropanol.

[0077] It was detected that the content of isopropanol in the ultra-high purity isopropanol was 99.9992%. The content of each metal ion in isopropanol before and after treatment is shown in Table 5.

[0078] Table 5 Detection results of the content of each metal ion impurity in ultra-high purity isopropanol

[0079]

[0080]

[0081] As can be seen from Table 5, the content of only part of the metal ion impurities in the isopropanol prepared by the method of the present comparative example is ≤0.01 ppb, which does not meet the SEMI Grade 5 standard.

[0082] Comparative Example 2

[0083] The present comparative example provides a method for preparing ultra-high purity isopropanol, which is the same as Example 1 in terms of the source of industrial grade isopropanol and other treatment steps, except that the ion exchange mixed material used in the ion exchange step is different, which is as follows:

[0084] The 99.7% industrial grade isopropanol was first subjected to vacuum rectification: the heating temperature of the column bottom was controlled at 20°C, the vacuum degree was 80 kPa, and the reflux ratio was 2, and isopropanol was collected from the bottom of the column; then subjected to atmospheric rectification: the heating temperature of the column bottom was controlled at 85°C, the reflux ratio was 1, and isopropanol was collected from the top of the column; finally subjected to ion exchange: the isopropanol was passed through a polystyrene cation exchange resin with a sulfonic group with a volume exchange flux of 1.5 mol / ml to obtain ultra-high purity isopropanol.

[0085] It was detected that the content of isopropanol in the ultra-high purity isopropanol was 99.9992%. The content of each metal ion in isopropanol before and after treatment is shown in Table 5.

[0086] Table 6 Detection results of the content of each metal ion impurity in ultra-high purity isopropanol

[0087]

[0088]

[0089] From Table 6, it can be seen that the content of only part of metal ion impurities in the super-high-purity isopropanol prepared by the comparative example is ≤0.01 ppb, which does not meet the SEMI Grade 5 standard.

[0090] From Examples 1-4, it can be seen that the content of each metal ion in the super-high-purity isopropanol prepared by the present application is less than 0.01 ppb, which meets the SEMI Grade 5 standard, and the content of isopropanol is greater than 99.999%, which is generally applicable to cleaning and drying of semiconductors, integrated circuits, etc.

[0091] From Comparative Example 1 and Example 4, it can be seen that the volume exchange flux of the ion exchange mixed material affects the purification effect, and insufficient volume exchange flux causes increased energy consumption.

[0092] From Comparative Example 1 and Comparative Examples 1-2, it can be seen that the selection of ion exchange mixed material significantly affects the removal effect of metal ions; for example, in Comparative Example 1, only a sulfonic acid group-containing cation exchange resin is used as the ion exchange material, and in Comparative Example 2, a sulfonic acid group-containing cation exchange resin and a triethyl group-containing anion exchange resin are used as the ion exchange mixed material, and the isopropanol prepared thereby has a content of only part of metal ion impurities ≤0.01 ppb, and a content of part of metal ion impurities greater than 0.01, which does not meet the SEMI Grade 5 standard. This indicates that when only a cation exchange resin is used for purification, or a triethyl group-containing anion exchange material is selected instead of the amine group-containing anion exchange material of the present application, the purification effect will be significantly reduced. In Comparative Example 1, only a sulfonic acid group-containing polystyrene cation exchange resin is used, and the adsorption-desorption of ions and functional groups on the resin appears dynamic balance, resulting in the inability to remove part of the cations. In Comparative Example 2, a sulfonic acid group-containing polystyrene cation exchange resin and a triethyl group-containing polystyrene anion exchange resin are used as the ion exchange mixed material, and after the anion group of the anion exchange resin in the ion exchange mixed material of the present application is replaced from an amine group to a triethyl group, the exchange of hydroxyl ions cannot be achieved 100% in the pretreatment stage, resulting in the remaining of other anions, such as chloride ions, which causes the generation of residual HCl in the solution. At this time, there is a balance between hydrogen ions and part of the cations, resulting in the inability to remove part of the cations.

[0093] In summary, the method of the present application sequentially subjects industrial-grade isopropyl alcohol to vacuum rectification, atmospheric rectification and ion exchange treatment using a specific ion exchange mixed material, which can efficiently and quickly remove the residual metal ions in the isopropyl alcohol without introducing other ions, so that the content of each metal ion in the ultra-high purity isopropyl alcohol prepared by the present application is less than 0.01 ppb, which meets the SEMI Grade 5 standard, and the content of isopropyl alcohol is greater than 99.999%. In addition, the preparation method of the present application is simple in operation and stable in product quality, and is suitable for industrial continuous production, which will promote the development of the integrated circuit industry to higher nanometer process.

[0094] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not contradict, they should be considered within the scope of the present disclosure.

[0095] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A process for the preparation of isopropyl alcohol, characterized in that, The method comprises the following steps: (1) vacuum rectification: the industrial-grade isopropyl alcohol is subjected to vacuum rectification under the conditions of a temperature of 10-60 ℃, a vacuum degree of 50-100 kPa, and a reflux ratio of 1-5; (2) atmospheric rectification: the isopropyl alcohol obtained in step (1) is subjected to atmospheric rectification under the conditions of a temperature of 80-95 ℃ and a reflux ratio of 1-5; (3) ion exchange: the isopropyl alcohol obtained in step (2) is subjected to ion exchange through a mixed ion exchange material to obtain the isopropyl alcohol; the mixed ion exchange material comprises a cation exchange material and an anion exchange material; the cation exchange material is selected from at least one of a polystyrene cation exchange resin with sulfonic acid groups, a polypropylene cation exchange resin with sulfonic acid groups, a nylon-66 cation membrane with sulfonic acid groups, and a polyphenylsulfone cation membrane with sulfonic acid groups; the anion exchange material is selected from at least one of a polystyrene anion exchange resin with primary amine groups, a polypropylene anion exchange resin with secondary amine groups, a nylon-66 anion membrane with tertiary amine groups, a polyphenylsulfone anion membrane with primary amine groups, and a polyphenylsulfone anion membrane with secondary amine groups.

2. The method of preparing isopropyl alcohol according to claim 1, wherein The ion molar amount of the cation exchange material in the mixed ion exchange material per unit volume capable of ion exchange is 1.5-3.0 mol / ml.

3. The method of claim 2, wherein the isopropyl alcohol is produced by the process of: The ion molar amount of the cation exchange material in the mixed ion exchange material per unit volume capable of ion exchange is 1.5-2.5 mol / ml. ​ 4. The method of claim 1, wherein the isopropyl alcohol is produced at a rate of at least 0.5 kg / hr per liter of the aqueous solution. The mixed ion exchange material is selected from at least one of the following mixed materials: a mixed material of a polystyrene cation exchange resin with sulfonic acid groups and a polystyrene anion exchange resin with primary amine groups; a mixed material of a polypropylene cation exchange resin with sulfonic acid groups and a polypropylene anion exchange resin with secondary amine groups; a mixed material of a nylon-66 cation membrane with sulfonic acid groups and a nylon-66 anion membrane with tertiary amine groups; a mixed material of a polyphenylsulfone cation membrane with sulfonic acid groups, a polyphenylsulfone anion membrane with primary amine groups, and a polyphenylsulfone anion membrane with secondary amine groups.

5. The method of claim 1, wherein the isopropyl alcohol is produced at a rate of at least 0.5 kg / hr per liter of the aqueous solution. The industrial-grade isopropyl alcohol contains at least one of lithium ions, beryllium ions, sodium ions, magnesium ions, aluminum ions, potassium ions, calcium ions, titanium ions, vanadium ions, chromium ions, manganese ions, iron ions, cobalt ions, nickel ions, copper ions, zinc ions, gallium ions, germanium ions, strontium ions, zirconium ions, niobium ions, molybdenum ions, palladium ions, silver ions, indium ions, tin ions, antimony ions, barium ions, tantalum ions, tungsten ions, platinum ions, gold ions, thallium ions, lead ions, and bismuth ions.

6. The method of claim 1, wherein the isopropyl alcohol is produced at a rate of at least 0.5 kg / hr. In step (1), the industrial-grade isopropyl alcohol is subjected to vacuum rectification under the conditions of a temperature of 20-40 ℃, a vacuum degree of 60-80 kPa, and a reflux ratio of 2-4.

7. The method of claim 1, wherein the isopropyl alcohol is produced at a rate of at least 0.5 kg / hr. In step (2), the isopropyl alcohol obtained in step (1) is subjected to atmospheric rectification under the conditions of a temperature of 85-95 ℃ and a reflux ratio of 1-3.

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