阅读说明：本技术 异丙醇纯化方法 (Isopropyl alcohol purification process ) 是由 金性均 李成圭 朴谢恩 于 2019-07-26 设计创作，主要内容包括：根据本申请的示例性实施方式的异丙醇的纯化方法包括：将包含异丙醇；水；和含有正丙醇的副产物的进料供给至共沸蒸馏纯化塔；从共沸蒸馏纯化塔的顶部分离出包含异丙醇、正丙醇和水的共沸物,并将该共沸物进料至脱水塔；从脱水塔的底部分离出异丙醇和正丙醇,并将异丙醇和正丙醇进料至正丙醇纯化塔；以及从正丙醇纯化塔的顶部分离出异丙醇。(The method for purifying isopropyl alcohol according to an exemplary embodiment of the present application includes: comprises isopropanol; water; and a feed containing a by-product of n-propanol is supplied to the azeotropic distillation purification column; separating an azeotrope comprising isopropanol, n-propanol and water from the top of the azeotropic distillation purification column and feeding the azeotrope to a dehydration column; separating isopropanol and n-propanol from the bottom of the dehydration column and feeding the isopropanol and n-propanol to an n-propanol purification column; and separating the isopropanol from the top of the n-propanol purification column.)

1. A process for purifying isopropanol, the process comprising:

comprises isopropanol; water; and a feed containing a by-product of n-propanol is supplied to the azeotropic distillation purification column;

separating an azeotrope comprising isopropanol, n-propanol and water from the top of the azeotropic distillation purification column and feeding the azeotrope to a dehydration column;

separating isopropanol and n-propanol from the bottom of the dehydration column and feeding the isopropanol and n-propanol to an n-propanol purification column; and

separating isopropanol from the top of the n-propanol purification column.

2. The process of claim 1, wherein water is separated from the bottom of the azeotropic distillation purification column.

3. The method according to claim 1, wherein an entrainer is additionally fed to the dehydration column.

4. The method of claim 3, further comprising: the entrainer and water are separated from the top of the dehydration column and fed to a water recovery column.

5. The method of claim 4, further comprising: the entrainer is separated from the top of the water recovery column and recycled to the dehydration column.

6. The method of claim 4, wherein the water is separated from the bottom of the water recovery column.

7. The process of claim 1, wherein the feed comprising isopropanol, water, and a byproduct containing n-propanol is a reactant produced by the reaction process of propylene and water.

8. The method of claim 7, further comprising:

separating n-propanol from the bottom of the n-propanol purification column and recycling the n-propanol to the reaction process of propylene and water.

9. The method according to claim 1, wherein the theoretical plate number of the n-propanol purification column is 40 to 80.

10. The method according to any one of claims 1 to 9, wherein the content of isopropanol is 99.8% or more based on the total weight of the product purified by the method for purifying isopropanol.

Technical Field

This application claims priority and benefit to korean patent application No. 10-2018-0152173, filed on 30.11.2018 from the korean intellectual property office, the entire contents of which are incorporated herein by reference.

The present application relates to a process for the purification of isopropanol.

Background

Isopropyl alcohol (IPA) has a variety of uses, including as a cleaning agent in the electronics industry (e.g., in the manufacture of, for example, semiconductors and Liquid Crystal Displays (LCDs)).

IPA can be produced using, for example, propylene, acetone, etc. as a raw material. In most cases, IPA reactants comprising a large amount of water are obtained during the preparation of IPA and together the reactants form an azeotrope comprising water. That is, water having a boiling point of about 100 ℃ and IPA having a boiling point of about 82.5 ℃ form an azeotrope having 87.9 wt% of IPA at an azeotropic temperature of about 80.4 ℃ under normal pressure, and therefore, it is required to efficiently prepare high-purity IPA by removing water from the feed and consume a large amount of energy to remove water through a simple distillation process. As a method for obtaining high-purity IPA from an azeotrope, a distillation method of extracting, adding an azeotropic agent as a material forming an azeotropic product, or the like is known.

Disclosure of Invention

[ problem ] to

The present application provides a process for the purification of isopropanol.

[ means of solution ]

An exemplary embodiment of the present application provides a method of purifying isopropanol, the method including:

comprises isopropanol; water; and a feed of a by-product comprising n-propanol is supplied to an azeotropic distillation purification column;

separating an azeotrope comprising isopropanol, n-propanol and water from the top of the azeotropic distillation purification column and feeding the azeotrope to the dehydration column;

separating isopropanol and n-propanol from the bottom of the dehydration column and supplying the isopropanol and n-propanol to an n-propanol purification column; and

isopropanol was separated from the top of the n-propanol purification column.

[ advantageous effects ]

The method for purifying isopropyl alcohol according to the exemplary embodiment of the present application may improve the separation efficiency of isopropyl alcohol (IPA) and n-propyl alcohol (NPA) because water may be removed and then isopropyl alcohol and n-propyl alcohol may be separated by feeding an azeotrope including isopropyl alcohol, n-propyl alcohol and water to a dehydration column.

In addition, since the purification method of isopropyl alcohol according to the exemplary embodiment of the present application may minimize the content of n-propanol in the final product, ultrapure (99.8 wt% or more) isopropyl alcohol may be prepared.

Drawings

Fig. 1 is a process diagram schematically illustrating a purification method of isopropyl alcohol according to the related art.

Fig. 2 is a process diagram schematically illustrating a method of purifying isopropyl alcohol according to an exemplary embodiment of the present application.

[ description of reference numerals and symbols ]

10: azeotropic distillation purification tower

20: dehydration tower

30: n-propanol purifying tower

40: water recovery tower

50: feeding of the feedstock

Detailed Description

Hereinafter, the present application will be described in more detail.

A process diagram of a purification method of isopropyl alcohol according to the related art is schematically shown in the following fig. 1.

As shown in fig. 1 below, in the related art, water is moved into the bottom of an azeotropic distillation purification column 10, an azeotrope containing isopropyl alcohol, n-propyl alcohol and water is separated from the top of the azeotropic distillation purification column 10, and n-propyl alcohol containing isopropyl alcohol and water is removed from an n-propyl alcohol purification column 30 connected to a side stripping structure. That is, the n-propanol purification column 30 in the related art has a structure in which water is inevitably present. However, the azeotropic point of isopropanol and water is 80.4 ℃ and the azeotropic point of n-propanol and water is 87.7 ℃ at atmospheric pressure, which is a condition under which it is difficult to separate isopropanol, n-propanol and water from each other, and thus there is a problem in that it is difficult to accurately separate only n-propanol from the n-propanol purification column 30 in the related art.

In addition, since a small amount of n-propanol is separated from the top of the azeotropic distillation purification column 10 and then transferred to a subsequent purification process in the related art, a small amount of n-propanol is present in the final product, so that there is a problem in that ultrapure isopropanol cannot be produced.

Accordingly, the present application is directed to a method of purifying isopropanol that can produce ultrapure isopropanol by first removing water prior to n-propanol removal.

The method for purifying isopropyl alcohol according to an exemplary embodiment of the present application includes: comprises isopropanol; water; and a feed containing a by-product of n-propanol is supplied to the azeotropic distillation purification column; separating an azeotrope comprising isopropanol, n-propanol and water from the top of the azeotropic distillation purification column and feeding the azeotrope to a dehydration column; separating isopropanol and n-propanol from the bottom of the dehydration column and feeding the isopropanol and n-propanol to an n-propanol purification column; and separating the isopropanol from the top of the n-propanol purification column.

The method for purifying isopropyl alcohol according to an exemplary embodiment of the present application includes: comprises isopropanol; water; and a feed of a by-product containing n-propanol is supplied to the azeotropic distillation purification column.

In exemplary embodiments of the present application, the feed comprising isopropanol, water, and a byproduct containing n-propanol may be reactants resulting from the reaction process of propylene and water. In this case, the n-propanol-containing by-product may contain one or more of ether, acetone, and the like, in addition to n-propanol.

The method for purifying isopropyl alcohol according to an exemplary embodiment of the present application includes: an azeotrope comprising isopropanol, n-propanol and water is separated from the top of the azeotropic distillation purification column and fed to the dehydration column.

In exemplary embodiments of the present application, water may be separated from the bottom of an azeotropic distillation purification column while an azeotrope comprising isopropanol, n-propanol, and water is separated from the top of the azeotropic distillation purification column.

The method for purifying isopropyl alcohol according to an exemplary embodiment of the present application includes: separating isopropanol and n-propanol from the bottom of the dehydration column and feeding the isopropanol and n-propanol to an n-propanol purification column.

In exemplary embodiments of the present application, the dehydration column may be additionally fed with an entrainer. As the entrainer, a material known in the art may be used, and more specifically, cyclohexane may be used, but the entrainer is not limited thereto. Further, after the entrainer is fed to the dehydration column during the initial operation of the dehydration column, the entrainer is separated from the top of the water recovery column and then recycled to the dehydration column, which will be described below.

In exemplary embodiments of the present application, the purification method may further include: the entrainer and water are separated from the top of the dehydration column and fed to a water recovery column. Further, in the water recovery column, water may be separated from the bottom of the water recovery column, an entrainer may be separated from the top of the water recovery column, and the separated entrainer may be recycled to the dehydration column.

The method for purifying isopropyl alcohol according to an exemplary embodiment of the present application includes: isopropanol was separated from the top of the n-propanol purification column.

In exemplary embodiments of the present application, n-propanol may be separated from the bottom of the n-propanol purification column, and the separated n-propanol may be recycled to the above-described reaction process of propylene and water. Since the isopropyl alcohol-forming reaction according to the reaction process of propylene and water is an equilibrium reaction with ether and n-propyl alcohol, the selectivity of isopropyl alcohol can be further improved by recycling n-propyl alcohol separated from the n-propyl alcohol purification column to the reaction process of propylene and water.

According to exemplary embodiments of the present application, since water is removed by feeding an azeotrope including isopropyl alcohol, n-propyl alcohol and water to a dehydration column and then isopropyl alcohol and n-propyl alcohol are separated in an n-propyl alcohol purification column, the separation efficiency of isopropyl alcohol (IPA) and n-propyl alcohol (NPA) may be improved. More specifically, since isopropyl alcohol and n-propanol have boiling points of 82.5 ℃ and 97.2 ℃, respectively, isopropyl alcohol and n-propanol can be easily separated when water is absent. Thus, according to exemplary embodiments of the present application, the separation efficiency of isopropanol and n-propanol in an n-propanol purification column may be increased by first removing water before feeding the feed to the n-propanol purification column.

In exemplary embodiments of the present application, the theoretical plate number of the n-propanol purification column may be 40 to 80, 45 to 75, and 50 to 70. When the number of theoretical plates of the n-propanol purification column is less than 40, the improvement in the separation efficiency may be small, and when the number of theoretical plates of the n-propanol purification column is more than 80, the investment cost of the apparatus may be excessively generated, which is not preferable.

A process diagram of a method for purification of isopropanol according to an exemplary embodiment of the present application is schematically shown in figure 2 below.

As shown in fig. 2 below, a method for purifying isopropyl alcohol according to an exemplary embodiment of the present application includes: comprises isopropanol; water; and a feed 50 containing a by-product of n-propanol is supplied to the azeotropic distillation purification column 10; separating an azeotrope comprising isopropanol, n-propanol and water from the top of the azeotropic distillation purification column 10 and feeding the azeotrope to the dehydration column 20; separating isopropanol and n-propanol from the bottom of the dehydration column 20 and feeding the isopropanol and n-propanol to an n-propanol purification column 30; and separating the isopropanol from the top of the n-propanol purification column 30. In addition, the purification method may further include: separating the entrainer and water from the top of the dehydration column 20 and feeding the entrainer and water to the water recovery column 40; and may further include: the entrainer is separated from the top of the water recovery column 40 and recycled to the dehydration column 20.

In the exemplary embodiment of the present application, the azeotropic distillation purification column, the dehydration column, the n-propanol purification column, the water recovery column, and the like are distillation apparatuses including a reboiler, a condenser, a column body (column), and the like, and distillation apparatuses known in the art may be used without particular limitation.

In exemplary embodiments of the present application, the content of isopropanol may be 99.8 wt% or more, 99.9 wt% or more, and less than 100 wt% based on the total weight of a purified product obtained by a purification process of isopropanol. When the content of isopropyl alcohol is less than 99.8 wt% based on the total weight of the purified product, ultrapure isopropyl alcohol cannot be prepared due to by-products other than isopropyl alcohol, and thus, many limitations occur when isopropyl alcohol is used in various applications including use as a cleaning agent in the electronics industry, such as the manufacture of semiconductors and Liquid Crystal Displays (LCDs).

[ modes for the invention ]

Hereinafter, the present application will be described in detail with reference to examples for specifically describing the present application. However, the embodiments according to the present application may be modified in various forms and should not be construed that the scope of the present application is limited to the embodiments described in detail below. The embodiments of the present application are provided to explain the present application more fully to those of ordinary skill in the art.

< example >

< examples 1 to 3 and comparative examples 1 to 4>

In the examples, isopropanol was purified according to the process scheme of figure 2 below. In the comparative example, the purification step of isopropanol was performed according to the process diagram of fig. 1 below. The number of theoretical plates and input energy of each method in examples and comparative examples are shown in table 1 below.

[ Table 1]

In Table 1, Q means the amount of energy input to each process, and the unit thereof is Gcal/hr.

< Experimental example >

The components of the isopropyl alcohols purified according to examples 1 to 3 and comparative examples 1 to 4 were analyzed, and the results are shown in table 2 below. The compositional analysis of the purified isopropanol was obtained by simulation with Aspen plus, a chemical process simulator.

[ Table 2]

	IPA(％)	NPA(ppm)	Water (ppm)
				Example 1	99.97	54	202
Example 2	99.98	16	202
				Example 3	99.98	5	202
Comparative example 1	99.93	506	202
				Comparative example 2	99.93	506	202
Comparative example 3	99.97	78	202
				Comparative example 4	99.97	78	202

As shown by the results in comparative example 2, when the plate number of the NPA purification column was increased in the prior art process, the NPA content in the final product was not changed, and as shown by the results in comparative example 3, when the energy input to the NPA purification column was increased, the NPA content in the final product was decreased in the prior art process. In addition, as a result in comparative example 4, it can be confirmed that, in the method of the related art, the effect of increasing the input energy is greater than the effect of increasing the number of plates of the NPA purification column.

According to the exemplary embodiment of the present application, the flow rate of the feed supplied to the dehydration column is increased by about 12% as compared to the method of the related art, and thus the energy supplied to the dehydration column and the water recovery column is increased.

As a result, the method of purifying isopropyl alcohol according to the exemplary embodiment of the present application may improve the separation efficiency of isopropyl alcohol (IPA) and n-propyl alcohol (NPA) because water is removed by feeding an azeotrope including isopropyl alcohol, n-propyl alcohol, and water to a dehydration column and then the isopropyl alcohol and the n-propyl alcohol are separated.

In addition, since the purification method of isopropyl alcohol according to the exemplary embodiment of the present application may minimize the content of n-propanol in the final product, ultrapure (99.8 wt% or more) isopropyl alcohol may be prepared.