Method for producing isopropyl alcohol

Abstract

The present invention provides a method for producing isopropyl alcohol (IPA), the method comprising the steps of (S1) preparing a crude isopropyl alcohol (IPA) product obtained by gas purification and isopropyl alcohol purification of the reaction product of propylene and water; (S2) supplying the crude IPA product to a first region of a separation-wall type distillation column including a first region, a second region, a top region and a bottom region; and (S3) separating water and low-boiling organic matter contained in the crude IPA product into the top region of the separation-wall type distillation column, separating high-boiling organic matter and inorganic matter contained in the crude IPA product into the bottom region, and obtaining purified isopropyl alcohol in liquid or gas phase in the second region.

Description

TECHNICAL FIELD

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0119579 filed on September 8, 2023, and all contents disclosed in the documents of the corresponding Korean patent application are incorporated herein as part of the present specification.

[0002] The present invention relates to a method for producing isopropyl alcohol, and more specifically, to a method for purifying high-purity isopropyl alcohol by removing both organic and inorganic impurities from a crude isopropyl alcohol product. BACKGROUND ART

[0003] Isopropyl alcohol (IPA) is used in various applications in the electronics industry such as the manufacture of semiconductors and LCDs (Liquid crystal displays), including cleaning agents, raw materials for industrial coatings and reagents, and solvents for paints, inks, and the like.

[0004] Such isopropyl alcohol can be produced by reacting propylene with water. Generally, referring to FIG. 1, isopropyl alcohol is produced as follows: propylene monomer and water are reacted in a reaction unit 100 to obtain a reaction product containing IPA along with by-products such as unreacted propylene monomer, unreacted water, n-propyl alcohol (NPA) and organic substances; the reaction product is transferred to a gas purification unit 200 to separate low-boiling-point gas components including unreacted propylene monomer; then, the reaction product from which gas components have been separated is supplied to an IPA purification unit 300 including a plurality of distillation columns to remove organic substances, NPA and water, thereby obtaining a crude isopropyl alcohol product.

[0005] The crude isopropyl alcohol product obtained through the gas purification section and the IPA purification section may still contain trace amounts of organic matter and water, and may contain inorganic substances (e.g., metallic components of Al, As, Fe, or Mg) that were present in the reaction water or reaction catalyst used as raw materials as impurities.

[0006] Inorganic impurities contained in the isopropyl alcohol can lead to a decrease in semiconductor yield when used for semiconductor cleaning. Therefore, depending on the type of impurity, it is required to control them at the ppb (parts per billion) or ppt (parts per trillion) level in the final product.

[0007] Conventionally, methods have been used to remove inorganic substances from crude isopropyl alcohol products obtained through a distillation process using filtration means equipped with a filter or metal ion adsorption means.

[0008] However, if the inorganic content in the crude isopropyl alcohol product is too high, it may be difficult to remove the inorganic substances to the level required in the semiconductor field by applying filtration or adsorption means alone. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention aims to solve the problems mentioned in the background art of the invention, and provides a method for purifying high-purity isopropyl alcohol by effectively removing inorganic substances along with residual organic substances from the crude product of isopropyl alcohol using a separation wall type distillation column. [Means for solving the problem]

[0010] According to one aspect of the present invention for solving the above problems, (S1) A step to prepare a crude isopropyl alcohol (IPA) product obtained by gas purification and isopropyl alcohol purification of the reaction product of propylene and water, (S2) The step of supplying the crude IPA product to the first region of a separation wall type distillation column, which includes a first region, a second region, a top region and a bottom region, A method for producing isopropyl alcohol is provided, comprising the steps of (S3) separating water and low-boiling organic matter contained in the crude IPA product in the top region of the separation wall-type distillation column, separating high-boiling organic matter and inorganic matter contained in the crude IPA product in the bottom region, and obtaining purified isopropyl alcohol in the liquid or gas phase in the second region.

[0011] In the above method, if the crude IPA product contains inorganic substances at a concentration of 50 ppb or less relative to the total weight, the purified isopropyl alcohol can be obtained in the liquid phase in the second region of the separation wall type distillation column. On the other hand, if the crude IPA product contains inorganic substances at a concentration of more than 50 ppb to 100 ppb relative to the total weight, the purified isopropyl alcohol can be obtained in the gas phase in the second region of the separation wall type distillation column.

[0012] In the second region of the separation wall type distillation column, the number of efflux stages for the purified isopropyl alcohol in the gas phase is lower than the number of efflux stages for the purified isopropyl alcohol in the liquid phase. [Effects of the Invention]

[0013] According to the present invention, by applying a separation wall-type distillation column to simultaneously remove organic and inorganic impurities contained in the crude IPA product, the purification efficiency of IPA can be improved.

[0014] Furthermore, the present invention can reduce energy consumption and improve the efficiency of inorganic substance removal by controlling the phase and number of outflow stages of the final IPA flowing out of the separation wall type distillation column according to the inorganic substance content level contained in the crude IPA product.

[0015] In other words, if the inorganic content in the crude IPA product is 50 ppb or less, the final IPA can be discharged in the liquid phase, thereby minimizing energy consumption and meeting the residual inorganic content requirements in the semiconductor field.

[0016] On the other hand, if the inorganic content in the crude IPA product exceeds 50 ppb, the limitations of inorganic removal by existing filtration or adsorption means can be overcome by effluenting the final IPA in the vapor phase to separate the inorganic substances in the form of ions or precipitates. [Brief explanation of the drawing]

[0017] [Figure 1] This diagram illustrates the typical manufacturing process for crude isopropyl alcohol (IPA). [Figure 2] This diagram schematically illustrates how, in one embodiment of the present invention, a separation wall distillation column (DWC) is applied to obtain highly purified IPA from crude IPA in either the liquid phase or the vapor phase. [Modes for carrying out the invention]

[0018] The terms and words used in the description and claims of this invention should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather should be interpreted in a manner consistent with the technical idea of ​​this invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0019] As used in this application, the meaning of “includes” or “contains” is to embody a particular characteristic, domain, constant, step, operation, element, or component, and not to exclude the addition of other particular characteristics, domain, constant, step, operation, element, or component.

[0020] As used herein, the term "stream" may refer to the flow of a fluid in a process, and may also refer to the fluid itself flowing in a pipe. Specifically, the stream can refer to both the fluid itself flowing in the piping connecting each device and the flow of the fluid at the same time. In addition, the fluid may comprise one or more components selected from gas, liquid and solid.

[0021] As used herein, unless otherwise specified, the term "top of the column" may refer to a location at a height of 0 to 20% downward from the topmost end of the apparatus, that is, the uppermost part. In addition, the term "bottom of the column" may refer to a location at a height of 80 to 100% downward from the topmost end of the apparatus, that is, the lowermost part.

[0022] In addition, "pressure" mentioned herein means gauge pressure measured based on atmospheric pressure.

[0023] One embodiment of the present invention relates to a method for producing isopropyl alcohol (IPA). Hereinafter, the method for producing IPA of the present invention will be described in detail with reference to the drawings.

[0024] First, a crude product of isopropyl alcohol (IPA) is provided (S1).

[0025] The crude IPA product may be purchased from commercially available products, or may be produced by conventional methods in the art.

[0026] Referring to Figure 1, in the reaction section 100, propylene monomer is reacted with water to obtain a reaction product containing IPA along with unreacted propylene monomer, unreacted water, n-propyl alcohol (NPA), and by-products such as organic matter. The reaction product is then transferred to the gas purification section 200, which includes an absorption column and a gas purification column, to separate unreacted propylene monomer and other low-boiling point gas components. The reaction product (containing IPA, NPA, water, and organic matter) from which the gas components have been separated is supplied to the IPA purification section 300, where, through a purification process carried out in numerous distillation columns, organic matter, NPA, and water are removed to obtain the crude isopropyl alcohol product.

[0027] The operating conditions for the gas purification unit and the IPA purification unit can be appropriately selected within the range commonly applied in the field, and are not particularly limited.

[0028] The crude IPA product was obtained by supplying the reaction product of propylene and water to a gas purification unit and an IPA purification unit to separate gaseous components, organic matter, etc., but it may still contain trace amounts of organic matter and water. In addition, inorganic substances (e.g., metallic components of Al, As, Fe, or Mg) that were present in the reaction water or reaction catalyst used as raw materials may be included as impurities.

[0029] For example, the crude IPA product may contain impurities of 0.08% by weight or less of water and low-boiling organic substances (e.g., isopropyl ether, acetone, etc.), 0.05% by weight or less of high-boiling organic substances (e.g., n-propyl alcohol, hexanol, etc.), and 100 ppb or less of inorganic substances (e.g., metal components such as Al, As, Fe, Mg, etc.) based on its total weight. The types and amounts of impurities contained in the crude IPA product may vary depending on the various environmental conditions associated with the reaction and purification processes.

[0030] To simultaneously remove trace amounts of water, organic matter, and inorganic matter contained in such crude IPA products, the present invention uses a dividing wall column (DWC) to produce highly purified IPA. The dividing wall column usable in the present invention is not particularly limited and can have a structure commonly used in petrochemical processes.

[0031] As schematically illustrated in Figure 2, the separation wall type distillation column used in the present invention may include a first region 10, a second region 20, a top region 30, and a bottom region 40, which are divided internally by a separation wall DW. The separation wall DW may be installed in the center of the distillation column, representing 30% to 70% or 35% to 65% of the total number of stages, but is not limited to this. As intermediate regions including the separation wall DW, the first region 10 represents a preliminary separation region, and the second region 20 represents a main separation region. On the other hand, the top region 30 and the bottom region 40 represent the uppermost and lowermost regions of the distillation column, respectively, which do not contain a separation wall DW.

[0032] In the first region 10, the second region 20, the top region 30, and the bottom region 40, which are separated by the separation wall DW, structures consisting of perforated plates or grid-like trays and packing beds formed by filling them with packing material in layers of appropriate height can be installed in multiple stages. At each stage of such structures, the rising gaseous stream and the descending liquid stream come into contact with each other, transferring heat and mass. As a result, some of the heavier components condense and drip down to the bottom, while the uncondensed vapor continues to rise to the top, a continuous process. The number and size of the structures are not particularly limited and can be set based on the number of theoretical stages inferred from the distillation curve considering the composition of the feed stream. Furthermore, the separation wall type distillation column may be equipped with a reboiler to transfer heat to the outflow stream of the bottom region 40 and a condenser to convert the outflow stream of the top flow 30 into the liquid phase.

[0033] In a separation wall-type distillation column of this structure, the crude IPA product prepared in the previous step is supplied as a feed to the first region 10, which is a preliminary separation region (S2).

[0034] The first region 10 may include one feed port, which may be located, for example, at a number of stages from the upper end of the first region, such as 30% to 70% or 35% to 65%. Here, the position of the feed port can be selected considering the type and amount of impurities contained in the crude IPA product, the desired purity and amount of residual impurities in the final IPA, energy consumption, and so on.

[0035] In the first region 10, preliminary separation of the crude IPA product is performed, and the relatively low-boiling-point components of the separated components can flow into the top region 30, while the relatively high-boiling-point components can flow into the bottom region 40.

[0036] In the second region 20, which serves as the main separation region, additional separation is performed based on the boiling point of the incoming components. As in the first region 10, relatively low-boiling-point components flow into the top region 30, relatively high-boiling-point components flow into the bottom region 40, and medium-boiling-point components are separated and can flow out into the side streams of the second region 20.

[0037] As a result, the crude IPA product supplied to the separation wall-type distillation column undergoes a continuous gas-liquid contact distillation process in each stage contained in the first preliminary separation region 10 and the second main separation region 20. Relatively low-boiling point organic matter rises in vapor form and flows out from the top region 30, while relatively heavier components, such as high-boiling point organic matter and inorganic matter, descend in condensed form and flow out from the bottom region 40. Isopropyl alcohol, from which the organic and inorganic matter have been separated, can be obtained on the side of the second region 20. Furthermore, the effluent from the top region 30 may contain trace amounts of water contained in the crude IPA product.

[0038] The components that flow out from the top region 30 of the column may include water and low-boiling point organic substances such as isopropyl ether and acetone. Some of these are discharged through the condenser, while the remainder can be refluxed back to the top region in liquid phase.

[0039] For the efficient separation of such low-boiling point organic substances, the top region 30 of the column is set to a temperature of 70-140°C or 75-110°C and a load of 0-5 kg / cm³. 2 ·g or 0-2kg / cm³ 2 It can be operated at a pressure of g.

[0040] The high-boiling point organic matter effluent from the bottom region 40 includes n-propyl alcohol, hexanol, or mixtures thereof, and the inorganic matter separated in the bottom region of the separation wall distillation column may include one or more metal components selected from Al, As, Fe, and Mg. The effluent from such bottom region 40 can be partially discharged via a reboiler, with the remainder refluxed to the bottom region in the gas phase.

[0041] For the efficient separation of such high-boiling point organic and inorganic substances, the bottom region 40 of the column is set to a temperature of 75-150°C or 80-120°C and a load of 0-6 kg / cm³. 2 ·g or 0-3kg / cm³ 2 It can be operated at a pressure of g.

[0042] Thus, when applying a separation-wall type distillation column, it is possible to simultaneously remove organic and inorganic impurities contained in the crude IPA product.

[0043] In one embodiment of the present invention, in the second region 20 of the separation wall-type distillation column, the side stream, i.e., the effluent phase and effluent position of the purified IPA, can be selected according to the composition of the crude IPA product supplied to the first region 10.

[0044] If the inorganic content in the crude IPA product is trace, for example, 50 ppb or less, the final purified IPA can be obtained in the liquid phase through the outlet of the side stream in the second region 20.

[0045] Specifically, the liquid phase IPA can be obtained by draining the liquid collected in a collector tray installed at a position 20% to 70% or 35% to 65% from the upper end of the second region 20 of the separation wall type distillation column. By maximizing the separation efficiency of the separation wall type distillation column when the drainage position is filled, energy consumption can be minimized, and the residual levels of organic and inorganic substances required in the semiconductor field can be met, thereby reducing consumption. Furthermore, since the drained liquid is a purified product of the raw material containing trace amounts of inorganic substances, it can meet the residual levels of inorganic substances required in the semiconductor field.

[0046] If the outflow position of the liquid phase IPA is higher than 20% from the upper end of the second region 20, the amount of low-boiling point organic matter remaining in the final product may be high, and if it is lower than 70%, the amount of high-boiling point organic matter remaining may be high.

[0047] On the other hand, if the inorganic content in the crude IPA product exceeds 50 ppb, the final purified IPA can be obtained in the vapor phase through the outlet of the side stream in the second region 20. Specifically, the vapor phase IPA can be obtained through a nozzle that provides a vapor rise path at a stage located 40% to 80% or 45% to 75% from the upper end of the second region of the separation wall distillation column.

[0048] In other words, the number of outflow stages of the gas-phase IPA must be lower than the number of outflow stages of the liquid-phase IPA. When this condition is met, inorganic substances contained in the stream remain in the form of ions or precipitates in the liquid and can be separated from the IPA that flows out in the gas phase, minimizing the presence of organic impurities in the IPA that flows out in the gas phase and meeting the level required in the semiconductor field.

[0049] If the outflow position of the gas-phase IPA is higher than 40% from the upper end of the second region 20, the amount of low-boiling point organic matter remaining in the gas-phase IPA may be high, and if it is lower than 80%, the amount of both organic and inorganic matter remaining in the gas-phase IPA may be high.

[0050] In one embodiment of the present invention, the flow rate of the purified liquid or gas phase that flows out to the side stream of the second region 20 in the separation wall-type distillation column can be 95% by weight or more of the total flow rate of the crude IPA product supplied to the first region 10.

[0051] Furthermore, the purified liquid or gas phase IPA, based on its weight, has a residual amount of low-boiling-point organic matter of less than 50 ppm, a residual amount of high-boiling-point organic matter of less than 20 ppm, and a residual amount of inorganic matter of less than 50 ppb, thus meeting the levels required in the semiconductor field.

[0052] As described above, according to the present invention, by applying a separation-wall type distillation column, organic and inorganic impurities contained in the crude IPA product can be removed simultaneously. By controlling the phase and number of outflow stages of the final IPA flowing out of the separation-wall type distillation column according to the inorganic content level contained in the crude IPA product, energy reduction can be achieved and the IPA purification efficiency can be improved.

[0053] In other words, if the inorganic content of the crude IPA product is 50 ppb or less, the final IPA can be discharged in the liquid phase, minimizing energy consumption and satisfying the residual levels of organic and inorganic materials required in the semiconductor field.

[0054] On the other hand, if the inorganic content in the crude IPA product exceeds 50 ppb, the limitations of inorganic removal by existing filtration or adsorption means can be overcome by effluenting the final IPA in the vapor phase to separate the inorganic substances in the form of ions or precipitates.

[0055] The present invention will be described in more detail below with reference to examples. However, the following examples are for illustrative purposes only, and it will be obvious to an ordinary person that various changes and modifications are possible within the scope of the present invention and the technical idea, and the scope of the present invention is not limited by these examples alone.

[0056] The following examples and comparative examples simulate the method according to the present invention using the commercial process simulation program AspenPlus. The constants required for the simulation were values ​​built into the program, values ​​described in the literature, etc.

[0057] Examples: Using the separation wall-type distillation column shown in Figure 2, high-purity IPA was purified from the crude IPA product.

[0058] First, a crude IPA product containing impurities was prepared with the composition shown in Table 1 below. This crude IPA product was then supplied to the first region 10 of a separation wall distillation column (DWC), and a separation process was carried out under the conditions shown in Table 1. The streams were then discharged into the top region 30, the bottom region 40, and the second region 20, respectively. The amount of residual impurities contained in the liquid or gas phase IPA discharged from the second region 20 and the total energy consumption by the separation wall distillation column were measured and are shown in Table 1 below.

[0059] [Table 1]

[0060] From Table 1 above, it can be confirmed that the number of phases and stages of the final IPA flowing out of the separation-wall type distillation column affects the amount of residual impurities in the final IPA and the energy consumption, based on the inorganic content (50 ppb) in the crude IPA product.

[0061] Specifically, in Example 1, crude IPA with an inorganic content of less than 50 ppb was supplied to the 50% position of the first region in a separation wall type distillation column, and the purified IPA was discharged in the liquid phase at the 40% position of the second region. As a result, energy consumption was low and the residual impurity level required in the semiconductor industry was met.

[0062] In Example 3, a crude IPA product with an inorganic content of less than 50 ppb was supplied to the stage at the 50% position of the first region, and the purified IPA was flushed out in the liquid phase at the 80% position of the second region. As a result, the residual amount of low-boiling point organic matter decreased, but the residual amount of high-boiling point organic matter increased, and ultimately, the residual impurity level could not be met.

[0063] In Example 2, crude IPA containing more than 50 ppb of inorganic substances was fed to the stage at the 50% position of the first region, and the purified IPA was effluent in the gas phase at the 60% position of the second region. As a result, energy consumption increased slightly, but the removal rate of inorganic substances contained in the feed was excellent, and the residual impurity level was met.

[0064] In Example 4, crude IPA containing more than 50 ppb of inorganic substances was supplied to the stage at the 50% position of the first region, and the purified IPA was leached out in the gas phase at the 20% position of the second region. As a result, energy consumption increased and the amount of residual low-boiling point organic matter remained high, ultimately failing to meet the residual impurity level.

[0065] On the other hand, in Example 5, the crude IPA product containing more than 50 ppb of inorganic substances was purified at the 40% position of the second region, and the purified IPA was discharged in the liquid phase. As a result, compared to Example 2, in which gas phase discharge was performed, it was advantageous in terms of energy consumption, but the removal rate of inorganic substances was poor, and the residual impurity level could not be met. [Explanation of symbols]

[0066] 100 reaction section 200 Gas Purification Section 300 IPA purification department DW Separation Wall 10. First Domain 20 Second Field 30 Tower Top Area 40. Base of the Tower

Claims

1. (S1) A step of preparing a crude isopropyl alcohol (IPA) product obtained by gas purification and isopropyl alcohol purification of the reaction product of propylene and water, (S2) The step of supplying the crude IPA product to the first region of a separation wall type distillation column, which includes a first region, a second region, a top region and a bottom region, (S3) A method for producing isopropyl alcohol, comprising the steps of: separating water and low-boiling organic matter contained in the crude IPA product in the top region of the separation wall-type distillation column; separating high-boiling organic matter and inorganic matter contained in the crude IPA product in the bottom region of the column; and obtaining purified isopropyl alcohol in the liquid or gas phase in the second region.

2. The method for producing isopropyl alcohol according to claim 1, wherein the crude IPA product contains as impurities 0.08% by weight or less of low-boiling point organic matter, 0.05% by weight or less of high-boiling point organic matter, and 100 ppb or less of inorganic matter, based on the total weight thereof.

3. The method for producing isopropyl alcohol according to claim 1, wherein when the crude IPA product contains 50 ppb or less of inorganic substances relative to the total weight, the isopropyl alcohol purified in the second region of the separation wall type distillation column is obtained in the liquid phase.

4. The method for producing isopropyl alcohol according to claim 1, wherein if the crude IPA product contains more than 50 ppb to 100 ppb of inorganic substances based on the total weight, the purified isopropyl alcohol is obtained in the gas phase in the second region of the separation wall type distillation column.

5. The method for producing isopropyl alcohol according to claim 1, wherein in the second region of the separation wall type distillation column, the number of efflux stages for the purified isopropyl alcohol in the gas phase is lower than the number of efflux stages for the purified isopropyl alcohol in the liquid phase.

6. The method for producing isopropyl alcohol according to claim 1, wherein the crude IPA product is supplied in stages at positions 30% to 70% from the upper end of the first region of the separation wall type distillation column.

7. The method for producing isopropyl alcohol according to claim 1, wherein the purified isopropyl alcohol of the liquid phase flows out from a stage number at a position 20 to 70 percent from the upper end of the second region of the separation wall type distillation column.

8. The method for producing isopropyl alcohol according to claim 1, wherein the purified isopropyl alcohol in the gas phase flows out from a stage number at a position 40 to 80 percent from the upper end of the second region of the separation wall type distillation column.

9. The method for producing isopropyl alcohol according to claim 1, wherein the low-boiling organic matter separated in the top region of the separation wall type distillation column includes isopropyl ether, acetone, or a mixture thereof.

10. The high-boiling organic matter separated in the bottom region of the separation wall type distillation column includes n-propyl alcohol, hexanol, or a mixture thereof. The method for producing isopropyl alcohol according to claim 1, wherein the inorganic substance separated in the bottom region of the separation wall type distillation column comprises one or more metal components selected from Al, As, Fe, and Mg.

11. A method for producing isopropyl alcohol according to any one of claims 1 to 10, wherein the purified isopropyl alcohol in the liquid or gas phase obtained in the second region of the separation wall type distillation column has, by weight, a residual amount of low-boiling organic matter of less than 50 ppm, a residual amount of high-boiling organic matter of less than 20 ppm, and a residual amount of inorganic matter of less than 50 ppb.

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