Method of preparing isopropyl alcohol

Abstract

The present invention provides a method of preparing isopropyl alcohol (IPA), and the method may comprise the steps of: (S1) preparing an isopropyl alcohol (IPA) crude product obtained by performing gas purification and isopropyl alcohol purification on a reaction product of propylene and water; (S2) supplying the IPA crude product to a first region of a divided wall distillation column including the first region, a second region, a column top region, and a column bottom region; and (S3) in the divided wall distillation column, separating water and a low boiling point organic material included in the IPA crude product by means of the column top region, separating a high boiling point organic material and an inorganic material included in the IPA crude product by means of the column bottom region, and obtaining purified isopropyl alcohol in a liquid or gas phase by means of the second region.

Description

Method for producing isopropyl alcohol

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0119579, filed September 8, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a method for producing isopropyl alcohol, and more particularly, to a method for purifying high-purity isopropyl alcohol by removing organic and inorganic impurities together from a crude isopropyl alcohol product.

[0005] Isopropyl alcohol (IPA) is used in a variety of applications, including as a solvent for cleaning agents, industrial paints and reagents, paints, and inks in the electronics industry, including semiconductor and liquid crystal display (LCD) manufacturing.

[0006] Such isopropyl alcohol can be produced by reacting propylene and water. Typically, isopropyl alcohol is produced by reacting propylene monomer and water in a reaction unit (100) as shown in FIG. 1 to obtain a reaction product including IPA, unreacted propylene monomer, unreacted water, n-propyl alcohol (NPA), and byproducts such as organic substances. The reaction product is then transferred to a gas purification unit (200) to separate low-boiling-point gas components including unreacted propylene monomer, and the reaction product from which the gas components have been separated is then 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.

[0007] The crude isopropyl alcohol product obtained through the above gas purification unit and IPA purification unit may still contain trace amounts of organic matter and water, and may contain impurities such as inorganic substances (e.g., metal components of Al, As, Fe, or Mg) present in the reaction water or reaction catalyst used as a raw material.

[0008] Since the inorganic impurities contained in the above isopropyl alcohol can cause a decrease in semiconductor yield when used for semiconductor cleaning, it is required to manage them at the ppb (parts per billion) or ppt (parts per trillion) level in the final product depending on the type of impurity.

[0009] Previously, methods for removing inorganic substances from crude isopropyl alcohol products that have undergone a distillation process have been performed using a filtration means equipped with a filter or a metal ion adsorption means.

[0010] However, if the content of inorganic substances in the above isopropyl alcohol crude product is excessive, it may be difficult to remove inorganic substances to the level required in the semiconductor field by applying only a filtration means or an adsorption means.

[0011] The present invention is intended to solve the problems mentioned in the background technology of the above invention, and provides a method for purifying high-purity isopropyl alcohol by effectively removing inorganic substances together with organic substances remaining in a crude isopropyl alcohol product using a dividing wall distillation column.

[0012] According to one aspect of the present invention for solving the above problem,

[0013] (S1) A step of preparing a crude product of isopropyl alcohol (IPA) obtained by performing gas purification and isopropyl alcohol purification on a reaction product of propylene and water;

[0014] (S2) a step of supplying the above IPA crude product to a first zone of a dividing wall distillation column including a first zone, a second zone, a top zone, and a bottom zone; and

[0015] (S3) A method for producing isopropyl alcohol is provided, including the steps of separating water and low-boiling-point organic substances included in the IPA crude product through a top region in the dividing wall distillation column, separating high-boiling-point organic substances and inorganic substances included in the IPA crude product through a bottom region, and obtaining purified isopropyl alcohol in a liquid or gaseous form through a second region.

[0016] In the above method, when the IPA crude product contains 50 ppb or less of inorganic substances based on the total weight, purified isopropyl alcohol can be obtained in a liquid phase in the second region of the dividing wall distillation column, while when the IPA crude product contains more than 50 ppb to 100 ppb of inorganic substances based on the total weight, purified isopropyl alcohol can be obtained in a gaseous phase in the second region of the dividing wall distillation column.

[0017] In the second zone of the above dividing wall distillation column, the number of outlet plates of the purified isopropyl alcohol in the gas phase is lower than the number of outlet plates of the purified isopropyl alcohol in the liquid phase.

[0018] According to the present invention, the purification efficiency of IPA can be improved by simultaneously removing organic and inorganic impurities contained in the crude IPA product by applying a dividing wall distillation column.

[0019] In addition, the present invention can improve the efficiency of removing inorganic substances while realizing energy savings by controlling the phase and number of outlet stages of the final IPA flowing out from the dividing wall distillation column according to the content level of inorganic substances included in the IPA crude product.

[0020] That is, when the content of inorganic substances contained in the above IPA crude product is 50 ppb or less, the final IPA can be discharged as a liquid phase, thereby minimizing energy consumption while satisfying the level of inorganic substance residue required in the semiconductor field.

[0021] Meanwhile, when the content of inorganic substances contained in the above IPA crude product exceeds 50 ppb, the limitations of inorganic substance removal by existing filtration or adsorption means can be overcome by discharging the final IPA into a vapor phase to separate the inorganic substances in the form of ions or precipitates.

[0022] Figure 1 illustrates a typical process for producing isopropyl alcohol (IPA) crude products.

[0023] FIG. 2 schematically illustrates obtaining highly purified IPA from crude IPA in a liquid phase or vapor phase by applying a dividing wall distillation column (DWC) in one embodiment of the present invention.

[0024] The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0025] As used herein, the terms “include” or “contain” specify a particular characteristic, area, integer, step, operation, element, or component, but do not exclude the addition of other particular characteristics, areas, integers, steps, operations, elements, or components.

[0026] The term "stream" as used herein may refer to the flow of fluid within a process, or may refer to the fluid itself flowing within a pipe. Specifically, the stream may refer to both the fluid itself flowing within the pipe connecting each device and the flow of the fluid. Furthermore, the fluid may include one or more components of gas, liquid, and solid.

[0027] As used herein, the term "top" may mean a point 0 to 20% below the top of the device, i.e., the uppermost point, unless otherwise specified. In addition, the term "bottom" may mean a point 80 to 100% below the top of the device, i.e., the lowermost point.

[0028] Additionally, the “pressure” referred to herein means gauge pressure measured relative to atmospheric pressure.

[0029]

[0030] 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.

[0031] First, prepare an isopropyl alcohol (IPA) crude product (S1).

[0032] The above IPA crude product can be purchased as a commercially available product or manufactured by a method conventional in the art.

[0033] Referring to FIG. 1, a propylene monomer and water are reacted in a reaction unit (100) to obtain a reaction product including unreacted propylene monomer, unreacted water, n-propyl alcohol (NPA), and by-products such as organic substances along with IPA, and then the reaction product is transferred to a gas purification unit (200) including an absorption tower, a gas purification tower, etc. to separate low-boiling-point gas components including unreacted propylene monomer. The reaction product (including IPA, NPA, water, and organic substances) from which the gas components are separated is supplied to an IPA purification unit (300), and the organic substances, NPA, and water are removed through a purification process performed in a plurality of distillation columns, thereby obtaining a crude product of isopropyl alcohol.

[0034] The operating conditions of the above gas purification unit and IPA purification unit can be appropriately selected within the range commonly applied in the relevant field, and there are no special restrictions.

[0035] The above IPA crude product was obtained by supplying the reaction product of propylene and water to a gas purification unit and an IPA purification unit to separate gas components, organic substances, etc., but may still contain trace amounts of organic substances and water. In addition, inorganic substances (e.g., metal components such as Al, As, Fe, or Mg) present in the reaction water or reaction catalyst used as a raw material may be included as impurities.

[0036] For example, the crude IPA product may contain impurities of water and low-boiling-point organic substances (e.g., isopropyl ether, acetone, etc.) of 0.08 wt% or less, high-boiling-point organic substances (e.g., n-propyl alcohol, hexanol, etc.) of 0.05 wt% or less, and inorganic substances (e.g., metal components such as Al, As, Fe, Mg, etc.) of 100 ppb or less, based on the total weight thereof. The types and contents of impurities contained in the crude IPA product may vary depending on various environments accompanying the reaction and purification processes.

[0037] To simultaneously remove trace amounts of water, organic matter, and inorganic matter contained in the crude IPA product, the present invention uses a dividing wall distillation column (DWC) to produce highly purified IPA. The dividing wall distillation column that can be used in the present invention may have a structure generally used in petrochemical processes without any particular limitations.

[0038] As schematically illustrated in FIG. 2, the dividing wall 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 therein by a dividing wall (DW). The dividing wall (DW) may be installed at 30% to 70% or 35% to 65% of the total number of plates from the inner center of the distillation column, but is not limited thereto. As the middle region including the dividing wall (DW), the first region (10) refers to a preliminary separation region, and the second region (20) refers to a main separation region. Meanwhile, the top region (30) and the bottom region (40) refer to the uppermost and lowermost regions of the distillation column which do not include the dividing wall (DW), respectively.

[0039] The first region (10), the second region (20), the top region (30), and the bottom region (40) separated by the above-mentioned dividing wall (DW) may be provided with a structure in multiple stages, which comprises a perforated plate or a grid-shaped tray and a packing filled thereon in layers of an appropriate height to form a packed bed. In each stage of the structure, a gaseous stream rising upward and a liquid stream descending downward come into contact with each other to transfer heat and mass, and as a result, a part of the heavy component is condensed and flows down to the bottom, and the uncondensed vapor continues to rise to the top, a process that is continuously performed. The number and size of the structure are not particularly limited, and can be set based on the theoretical number of plates, etc. inferred from a distillation curve considering the composition of the feed stream. In addition, the dividing wall distillation column may be provided with a reboiler that transfers heat to the outlet stream of the bottom region (40), and a condenser that converts the outlet stream of the top stream (30) into a liquid phase.

[0040] In a dividing wall distillation column of this structure, the crude IPA product prepared in the previous step is supplied as feed to the first region (10), which is a preliminary separation region (S2).

[0041] The first region (10) may include one supply port, and the supply port may be located at a height of, for example, 30% to 70% or 35% to 65% from the upper end of the first region. At this time, the location of the supply port may be selected in consideration of the type and content of impurities contained in the IPA crude product, the desired purity and residual amount of impurities of the final IPA, energy consumption, etc.

[0042] In the first region (10), preliminary separation of the IPA crude product is performed, and among the separated components, relatively low-boiling-point components can be introduced into the top region (30), and relatively high-boiling-point components can be introduced into the bottom region (40).

[0043] The second region (20) is a main separation region where additional separation is performed according to the boiling points of the introduced components. Among the separated components, as in the first region (10), relatively low-boiling-point components are introduced into the top region (30), relatively high-boiling-point components are introduced into the bottom region (40), and medium-boiling-point components can be separated and discharged as a side stream of the second region (20).

[0044] As a result, the IPA crude product supplied to the dividing wall distillation column undergoes a distillation process by continuous gas-liquid contact in each stage included in the first region (10) of the preliminary separation and the second region (20) of the main separation, and relatively low-boiling-point organic substances rise in a vapor state and are discharged from the top region (30), and relatively heavy components, high-boiling-point organic substances and inorganic substances, descend in a condensed state and are discharged from the bottom region (40), and isopropyl alcohol from which the organic substances and inorganic substances are separated can be obtained from the side of the second region (20). In addition, the discharge from the top region (30) may contain a trace amount of water that was included in the IPA crude product.

[0045] The components flowing out from the top section (30) may include water and low-boiling-point organic substances such as isopropyl ether and acetone, and some of them may be discharged through a condenser and the remainder may be refluxed back to the top section in a liquid state.

[0046] For efficient separation of these low-boiling-point organic substances, the top section (30) is set to a temperature of 70 to 140°C or 75 to 110°C and a pressure of 0 to 5 kg / cm 2· g or 0 to 2 kg / cm 2· It can be driven at a pressure of g.

[0047] The high-boiling point organic matter discharged from the above bottom zone (40) includes n-propyl alcohol, hexanol, or a mixture thereof, and the inorganic matter separated into the bottom zone of the above dividing wall distillation column may include one or more metal components selected from Al, As, Fe, and Mg. The discharged matter from the bottom zone (40) may pass through a reboiler, and some of it may be discharged and the remainder may be refluxed to the bottom zone as a gaseous phase.

[0048] For efficient separation of these high-boiling-point organic and inorganic substances, the bottom zone (30) is maintained at a temperature of 75 to 150°C or 80 to 120°C and a pressure of 0 to 6 kg / cm 2· g or 0 to 3 kg / cm 2· It can be driven at a pressure of g.

[0049] In this way, when a dividing wall distillation column is applied, organic and inorganic impurities contained in the IPA crude product can be removed simultaneously.

[0050]

[0051] In one embodiment of the present invention, the phase and outlet position of the side stream, i.e., purified IPA, in the second zone (20) of the dividing wall distillation column can be selected according to the composition of the IPA crude product supplied to the first zone (10).

[0052] When the content of inorganic substances contained in the above IPA crude product is a trace amount, for example, 50 ppb or less, the final purified IPA can be obtained in a liquid phase through the outlet of the side stream in the second region (20).

[0053] Specifically, the liquid IPA can be obtained by discharging the liquid collected in a collector tray installed at a position of 20% to 70% or 35% to 65% from the upper end of the second region (20) of the dividing wall distillation column. When the discharging position is satisfied, the separation efficiency of the dividing wall distillation column can be maximized, thereby minimizing energy consumption and satisfying the residual levels of organic and inorganic substances required in the semiconductor field. Consumption can be reduced. In addition, since the discharging liquid is a purified product of a feedstock containing a trace amount of inorganic substances, it can satisfy the residual levels of inorganic substances required in the semiconductor field.

[0054] If the location of the leakage of the above liquid IPA is higher than 20% from the upper part of the second region (20), the residual amount of low-boiling-point organic matter in the final product may increase, and if it is lower than 70%, the residual amount of high-boiling-point organic matter may increase.

[0055] Meanwhile, when the content of inorganic substances contained in the above IPA crude product exceeds 50 ppb, the final purified IPA can be obtained in a vapor phase through the outlet of the side stream in the second region (20). Specifically, the above-mentioned vaporous IPA can be obtained through a nozzle that provides a vapor upward path at a stage located at 40% to 80% or 45% to 75% from the upper end of the second region of the above-mentioned dividing wall distillation column.

[0056] That is, the number of outlets of the above-mentioned gaseous IPA must be lower than the number of outlets of the liquid IPA, and when this is satisfied, the inorganic substances contained in the stream remain in the form of ions or precipitates in the liquid and can be separated from the IPA outletted in the gaseous phase, and the organic impurities in the IPA outletted in the gaseous phase can be minimized, thereby meeting the level required in the semiconductor field.

[0057] If the location of the outflow of the above-mentioned gaseous IPA is higher than 40% from the upper part of the second region (20), the residual amount of low-boiling-point organic matter in the gaseous IPA may increase, and if it is lower than 80%, the residual amount of both organic matter and inorganic matter in the gaseous IPA may increase.

[0058] In one embodiment of the present invention, the flow rate of purified IPA in liquid or gaseous form discharged as a side stream of the second region (20) in the dividing wall distillation column may be 95 wt% or more of the total flow rate of the crude IPA product supplied to the first region (10).

[0059] In addition, the purified IPA in liquid or gaseous form 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 based on its weight, which can satisfy the level required in the semiconductor field.

[0060] According to the present invention as described above, by applying a dividing wall distillation column, organic and inorganic impurities contained in an IPA crude product can be simultaneously removed, and by controlling the phase and number of outlet stages of the final IPA flowing out from the dividing wall distillation column according to the content level of the inorganic substances contained in the IPA crude product, the IPA purification efficiency can be improved while saving energy.

[0061] That is, when the inorganic content of the above IPA crude product is 50 ppb or less, the final IPA can be discharged as a liquid phase, thereby minimizing energy consumption while satisfying the organic and inorganic residual levels required in the semiconductor field.

[0062] Meanwhile, when the inorganic content of the above IPA crude product exceeds 50 ppb, the limitation of inorganic removal by existing filtration or adsorption means can be overcome by discharging the final IPA into a vapor phase to separate the inorganic matter in the form of ions or precipitates.

[0063] Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are intended to illustrate the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present invention, and the scope of the present invention is not limited to these examples alone.

[0064] The following examples and comparative examples simulate the method according to the present invention using the commercial process simulation program Aspen Plus. The constants required for the simulations were values ​​built into the program and values ​​described in the literature.

[0065]

[0066] Examples:

[0067] High-purity IPA was purified from crude IPA using the dividing wall distillation column of Fig. 2.

[0068] First, an IPA crude product containing impurities was prepared with a composition as shown in Table 1 below, and then the IPA crude product was supplied to a first region (10) of a dividing wall distillation column (DWC) and a separation process was performed under the conditions shown in Table 1, so that each stream was discharged to a top region (30), a bottom region (40), and a second region (20). The content of residual impurities contained in the liquid or gaseous IPA discharged from the second region (20) and the total energy consumption in the dividing wall distillation column were measured and shown in Table 1 below.

[0069]

[0070] From the above Table 1, it can be confirmed that the phase and number of stages of the final IPA flowing out from the dividing wall distillation column based on the inorganic content (50 ppb) contained in the IPA crude product affect the content of residual impurities in the final IPA and the energy consumption. Specifically, in Example 1, the crude IPA product having an inorganic content of less than 50 ppb was supplied to the stage at the 50% position of the first region in the dividing wall distillation column, and the purified IPA was discharged in a liquid phase at the 40% position of the second region, thereby being able to satisfy the residual impurity level required in the semiconductor industry while consuming less energy.

[0071] In Example 3, the crude IPA product having an inorganic content of less than 50 ppb was supplied to a single unit at the 50% position of the first region, and the purified IPA was discharged in a liquid phase at the 80% position of the second region. As a result, the residual amount of low-boiling-point organic substances decreased, but the residual amount of high-boiling-point organic substances increased, so that the final impurity residual level was not satisfied.

[0072] In Example 2, crude IPA having an inorganic content exceeding 50 ppb was supplied to a single unit at the 50% position of the first zone, and purified IPA was discharged as a gas at the 60% position of the second zone. As a result, energy consumption increased somewhat, but the removal rate of inorganic matter included in the feed was excellent, so that the residual level of impurities could be satisfied.

[0073] In Example 4, the crude IPA product having an inorganic content exceeding 50 ppb was supplied to a single unit at the 50% position of the first zone and purified IPA was discharged as a gas at the 20% position of the second zone. As a result, energy consumption increased and the residual amount of low-boiling-point organic matter was high, ultimately failing to meet the residual impurity level.

[0074] Meanwhile, Example 5 was advantageous in terms of energy consumption compared to Example 2, which performed gaseous discharge, as a result of purifying IPA crude product with an inorganic content exceeding 50 ppb at a position of 40% of the second region and discharging it in a liquid phase, but the inorganic removal rate was poor, so the residual impurity level could not be satisfied.

[0075] [Explanation of symbols]

[0076] 100: Reaction section

[0077] 200: Gas Purification Unit

[0078] 300: IPA purification unit

[0079] DW: Separation wall

[0080] 10: Area 1

[0081] 20: Second Area

[0082] 30: Top area

[0083] 40: Top-bottom area

Claims

1. (S1) A step of preparing a crude product of isopropyl alcohol (IPA) obtained by performing gas purification and isopropyl alcohol purification on a reaction product of propylene and water; (S2) a step of supplying the above IPA crude product to a first zone of a dividing wall distillation column including a first zone, a second zone, a top zone, and a bottom zone; and (S3) A method for producing isopropyl alcohol, comprising the steps of separating water and low-boiling-point organic substances contained in the IPA crude product through a top region in the dividing wall distillation column, separating high-boiling-point organic substances and inorganic substances contained in the IPA crude product through a bottom region, and obtaining purified isopropyl alcohol in a liquid or gaseous form through a second region.

2. In paragraph 1, A method for producing isopropyl alcohol, wherein the above IPA crude product contains impurities of 0.08 wt% or less of low-boiling-point organic substances, 0.05 wt% or less of high-boiling-point organic substances, and 100 ppb or less of inorganic substances based on the total weight thereof.

3. In paragraph 1, A method for producing isopropyl alcohol, wherein purified isopropyl alcohol is obtained in a liquid phase in a second zone of the dividing wall distillation column when the above IPA crude product contains 50 ppb or less of inorganic matter based on the total weight.

4. In paragraph 1, A method for producing isopropyl alcohol, wherein purified isopropyl alcohol is obtained in a gaseous form in a second zone of a dividing wall distillation column when the above IPA crude product contains more than 50 ppb to 100 ppb of inorganic substances based on the total weight.

5. In paragraph 1, A method for producing isopropyl alcohol, wherein in the second zone of the above dividing wall distillation column, the number of outlet plates of the purified isopropyl alcohol in the gas phase is lower than the number of outlet plates of the purified isopropyl alcohol in the liquid phase.

6. In paragraph 1, A method for producing isopropyl alcohol, wherein the above IPA crude product is supplied at a stage at a position of 30% to 70% from the top of the first region of the above dividing wall distillation column.

7. In paragraph 1, A method for producing isopropyl alcohol, wherein the above-mentioned liquid purified isopropyl alcohol is discharged from a stage at a position of 20 to 70% from the upper part of the second region of the above-mentioned dividing wall distillation column.

8. In paragraph 1, A method for producing isopropyl alcohol, wherein the purified isopropyl alcohol of the above-mentioned gas is discharged from a stage at a position of 40 to 80% from the upper part of the second region of the dividing wall distillation column.

9. In paragraph 1, A method for producing isopropyl alcohol, wherein the low-boiling-point organic matter separated from the top region of the above-mentioned dividing wall distillation column comprises isopropyl ether, acetone or a mixture thereof.

10. In paragraph 1, The high boiling point organic matter separated into the bottom region of the above dividing wall distillation column includes n-propyl alcohol, hexanol or a mixture thereof, A method for producing isopropyl alcohol, wherein the inorganic material separated into the bottom region of the above dividing wall distillation column includes one or more metal components selected from Al, As, Fe, and Mg.

11. In paragraph 1, A method for producing isopropyl alcohol, wherein the purified isopropyl alcohol in a liquid or gaseous form obtained from the second region of the dividing wall distillation column 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 based on the weight thereof.

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