WO2023234202A1

WO2023234202A1 - Isopropyl alcohol accommodating body, manufacturing method for said accommodating body, and quality control method for isopropyl alcohol accommodating body

Info

Publication number: WO2023234202A1
Application number: PCT/JP2023/019666
Authority: WO
Inventors: 彬人本田; 雄輝山口; 裕貴田森
Original assignee: 株式会社トクヤマ
Priority date: 2022-06-03
Filing date: 2023-05-26
Publication date: 2023-12-07
Also published as: JPWO2023234202A1; JP7477730B1

Abstract

Provided is an isopropyl alcohol accommodating body that accommodates isopropyl alcohol in a container. The isopropyl alcohol accommodating body has, in the container, an oxygen content of 0.001 to 0.100 mol ppm with respect to the isopropyl alcohol, and the content of acetone as an impurity in the isopropyl alcohol is 10 to 200 ppb based on mass. Also provided are a manufacturing method for the isopropyl alcohol accommodating body and a quality control method for the isopropyl alcohol accommodating body.

Description

Isopropyl alcohol container, method for manufacturing the container, and quality control method for isopropyl alcohol container

The present disclosure relates to an isopropyl alcohol container in which isopropyl alcohol is stored in a container, a method for manufacturing the container, and a quality control method for the isopropyl alcohol container.

Isopropyl alcohol (also referred to as 2-propanol) is an organic solvent used in a variety of applications, particularly as a cleaning liquid or drying liquid in the manufacturing process of semiconductor devices. In recent years, with the demand for higher performance in semiconductor devices, the miniaturization and higher integration of elements and wiring are progressing, and there is a demand for isopropyl alcohol used as a cleaning liquid or drying liquid to be highly purified with extremely low metal impurities. This is becoming more and more common.

For example, Patent Document 1 states that when isopropyl alcohol with increased impurities due to long-term storage is used for cleaning purposes in the manufacturing process of semiconductor devices, residues derived from the impurities in the isopropyl alcohol remain on the surface of the semiconductor device after cleaning and drying. It has been described that this may cause defects in semiconductor devices. As can be seen from this, the influence of the quality of isopropyl alcohol used as a cleaning liquid or drying liquid on the yield of semiconductor devices cannot be ignored, and there is a strong demand for improving the quality of isopropyl alcohol.

Additionally, isopropyl alcohol contains organic impurities such as acetone, and it is known that when the dissolved oxygen concentration in isopropyl alcohol is high, the content of organic impurities in isopropyl alcohol increases. (For example, see Patent Document 2 or 3). As a method for reducing the dissolved oxygen concentration in isopropyl alcohol, Patent Document 2 proposes a method of controlling the oxygen partial pressure in the gas phase of the distillation column in the distillation step during the production of isopropyl alcohol. Further, Patent Document 3 proposes a method of removing dissolved oxygen by blowing and bubbling an inert gas such as nitrogen into isopropyl alcohol.

International Publication No. 2020/071307 International Publication No. 2018/135408 JP2014-201524A International Publication No. 2020/009225

According to the method described in Patent Document 2 or 3, high purity isopropyl alcohol with a reduced dissolved oxygen concentration can be produced. The manufactured isopropyl alcohol is stored in a storage tank, and then filled into containers such as ISO (International Organization for Standardization) tank containers, canisters, etc., and then shipped and delivered. Patent Document 4 describes filling a container with high-purity nitrogen gas.

Isopropyl alcohol filled in containers such as ISO tank containers and canisters may take several tens of days to several months before being used as a cleaning liquid or drying liquid in the semiconductor device manufacturing process. The present inventors investigated and found that even when a container is filled with isopropyl alcohol with a low dissolved oxygen concentration produced by the above method and sealed with nitrogen gas with a low oxygen concentration, the When the isopropyl alcohol in the container was analyzed after it was emptied, it was found that the content of metal impurities and organic impurities such as acetone increased, making it unusable for semiconductor cleaning applications.

Therefore, an object of the present disclosure is to provide an isopropyl alcohol container that suppresses an increase in the content of metal impurities and organic impurities such as acetone even after long-term storage, and a method for producing the same.

The present inventors have made extensive studies to solve the above problems. First, we confirmed that the containers had a high content of metal impurities and organic impurities such as acetone, and found that even if the containers were filled with isopropyl alcohol supplied from the same storage tank and sealed using the same nitrogen gas, It was found that the content of metal impurities and organic impurities such as acetone may be high. We also checked the dissolved oxygen concentration in the lot of isopropyl alcohol used at that time and the oxygen concentration in the nitrogen gas used for encapsulation, but neither of them were found to be problematic. In addition, even if the same container is filled with isopropyl alcohol with the same dissolved oxygen concentration and sealed with nitrogen gas with the same oxygen concentration and stored for a long time, metal impurities and acetone in the isopropyl alcohol will be removed. It was also confirmed that the increase in the content of organic impurities was suppressed in some cases. Based on these findings, it was confirmed that there was no damage to the containers used. On the other hand, when containers with high contents of metal impurities and organic impurities such as acetone were confirmed, it was found that the oxygen concentration in the gas phase inside the container and the content of chromium in isopropyl alcohol were high.

From these findings, the reason for the increase in the content of organic impurities such as acetone and chromium during long-term storage is that the oxygen concentration immediately after filling increases for some reason, and the oxygen in the container causes the content of acetone and other organic impurities to increase during long-term storage. It was assumed that the content of organic impurities and chromium increased. By filling the container with isopropyl alcohol and sealing it with an inert gas such as nitrogen, the oxygen concentration of the gas inside the container is kept below a predetermined concentration, so that the content of organic impurities such as acetone can be reduced over time during long-term storage. It was found that this increase could be suppressed, leading to the completion of the present invention.

Specific means for solving the above problems include the following embodiments.
<1> An isopropyl alcohol container containing isopropyl alcohol in a container,
The oxygen content in the container is 0.001 to 0.100 molppm relative to the isopropyl alcohol,
The isopropyl alcohol container has a content of acetone as an impurity in the isopropyl alcohol of 10 to 200 ppb on a mass basis.

<2> The isopropyl alcohol container according to <1>, wherein the content of chromium as an impurity in the isopropyl alcohol is 0.01 to 2.50 ppt on a mass basis.

<3> The isopropyl alcohol container according to <1> or <2>, wherein the volume of the container is in the range of 1,000 to 1,500,000 L.

<4> The isopropyl alcohol container according to <3>, wherein the container is an intermediate bulk container, a tank truck, an ISO tank container, or a storage tank.

<5> A method for producing an isopropyl alcohol container in which isopropyl alcohol is contained in a container, the method comprising:
A method for producing an isopropyl alcohol container, in which when isopropyl alcohol is stored in the container, the oxygen concentration of the gas in the container is 0.1 to 10 ppm on a volume basis.

<6> The isopropyl alcohol according to <5>, wherein the dissolved oxygen concentration in the isopropyl alcohol contained in the container is 0.001 to 0.050% with respect to the oxygen saturated solubility at 25°C in the atmosphere. Method for manufacturing a container.

<7> The method for producing an isopropyl alcohol container according to <5> or <6>, wherein the content of acetone as an impurity in the isopropyl alcohol contained in the container is 10 to 200 ppb on a mass basis.

<8> The isopropyl according to any one of <5> to <7>, wherein the content of chromium as an impurity in the isopropyl alcohol contained in the container is 0.01 to 2.50 ppt on a mass basis. A method for producing an alcohol container.

<9> The method for producing an isopropyl alcohol container according to any one of <5> to <8>, wherein the volume of the container is in the range of 1,000 to 1,500,000 L.

<10> The method for producing an isopropyl alcohol container according to <9>, wherein the container is an intermediate bulk container, a tank truck, an ISO tank container, or a storage tank.

<11> A method for producing an isopropyl alcohol container in which isopropyl alcohol is stored in a container, comprising:
The isopropyl alcohol is contained in an amount of 2 to 98% of the volume of the container,
A method for producing an isopropyl alcohol container, in which when isopropyl alcohol is stored in the container, the oxygen concentration of the gas in the container is 0.1 to 10 ppm on a volume basis.

<12> The isopropyl alcohol according to <11>, wherein the dissolved oxygen concentration in the isopropyl alcohol contained in the container is 0.001 to 0.050% with respect to the oxygen saturated solubility at 25°C in the atmosphere. Method for manufacturing a container.

<13> The method for producing an isopropyl alcohol container according to <11> or <12>, wherein the content of acetone as an impurity in the isopropyl alcohol contained in the container is 10 to 200 ppb on a mass basis.

<14> The isopropyl according to any one of <11> to <13>, wherein the content of chromium as an impurity in the isopropyl alcohol contained in the container is 0.01 to 2.50 ppt on a mass basis. A method for producing an alcohol container.

<15> The method for producing an isopropyl alcohol container according to any one of <11> to <14>, wherein the volume of the container is in the range of 1,000 to 1,500,000 L.

<16> The method for producing an isopropyl alcohol container according to <15>, wherein the container is an intermediate bulk container, a tank truck, an ISO tank container, or a storage tank.

<17> A method for producing an isopropyl alcohol container in which isopropyl alcohol contained in a first container is stored in a second container, comprising:
A method for producing an isopropyl alcohol container, in which when isopropyl alcohol is stored in the second container, the oxygen concentration of the gas in the second container is 0.1 to 10 ppm on a volume basis.

<18> The concentration of dissolved oxygen in the isopropyl alcohol contained in the second container is 0.001 to 0.050% with respect to the oxygen saturated solubility at 25°C in the atmosphere, as described in <17>. A method for producing an isopropyl alcohol container.

<19> The method for producing an isopropyl alcohol container according to <17> or <18>, wherein the content of acetone as an impurity in the isopropyl alcohol contained in the second container is 10 to 200 ppb on a mass basis. .

<20> In any one of <17> to <19>, the content of chromium as an impurity in the isopropyl alcohol contained in the second container is 0.01 to 2.50 ppt on a mass basis. A method for producing the isopropyl alcohol container described above.

<21> The method for producing an isopropyl alcohol container according to any one of <17> to <20>, wherein the volume of the container is in the range of 1,000 to 1,500,000 L.

<22> The method for producing an isopropyl alcohol container according to <21>, wherein the container is an intermediate bulk container, a tank truck, an ISO tank container, or a storage tank.

<23> A method for quality control of an isopropyl alcohol container in which isopropyl alcohol is stored in a container,
The dissolved oxygen concentration in the isopropyl alcohol is 0.001 to 0.050% with respect to the oxygen saturated solubility at 25 ° C. in the atmosphere, and the oxygen concentration of the gas in the container is 0.1 on a volume basis. A quality control method for an isopropyl alcohol container with a concentration of ~10 ppm.

According to the present disclosure, it is possible to provide an isopropyl alcohol container that can suppress an increase in the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage. In particular, the manufacturing method of the present disclosure can be applied to cases where isopropyl alcohol is stored in a container with a large internal volume, such as an ISO tank container or a storage tank. The isopropyl alcohol container of the present disclosure can be stored for a long time from several tens of days to several months, and the contained isopropyl alcohol can be suitably used as a cleaning liquid or drying liquid for semiconductor devices, and is suitable for industrial use. Probability is high.

In this specification, unless otherwise specified, the notation "A to B" using numerical values A and B means "above A and below B". In such a notation, if a unit is attached only to the numerical value B, the unit shall also be applied to the numerical value A.

In the following description, unless otherwise specified, "%", "ppm", "ppb", and "ppt" expressing concentration are all based on mass, including in the examples. In addition, "vol%" and "volppm" representing the concentration both indicate the volume fraction, including the examples, and "molppm" indicates the mole fraction.

<Isopropyl alcohol container>
The isopropyl alcohol container (hereinafter also simply referred to as "container") of the present disclosure is a container in which isopropyl alcohol is stored, and the oxygen content in the container is 0.001 relative to isopropyl alcohol. ~0.100 molppm, and the content of acetone as an impurity in isopropyl alcohol is 10 to 200 ppb. The inside of the container consists of a part filled with isopropyl alcohol (hereinafter referred to as the "liquid phase part") and a space part not filled with isopyl alcohol (hereinafter referred to as the "gas phase part"). (Also referred to as "Department").

By using such a container, the increase in the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage is suppressed, and long-term storage from several tens of days to several months is possible. Although the reason is not necessarily clear, the present inventors speculate as follows.

If oxygen is present in isopropyl alcohol, the oxygen and isopropyl alcohol react and acetone is produced as a by-product. Therefore, by filling a container with isopropyl alcohol, which has a low concentration of dissolved oxygen, and sealing it with an inert gas such as nitrogen gas, the increase in the content of organic impurities such as acetone in the isopropyl alcohol in the container can be suppressed. It was considered a thing. However, if there is a very small gap in the piping for transferring the liquid from the storage tank to the container, the piping for sealing in nitrogen gas, etc., a very small amount of oxygen may be mixed in. Further, containers such as ISO tank containers are often returned after the isopropyl alcohol inside is consumed, and the same container is filled with isopropyl alcohol and reshipped. Normally, isopropyl alcohol is filled after the container has been thoroughly cleaned, but it is possible that oxygen may remain in the container due to the cleaning at that time.

In such a case, even if the container is filled with isopropyl alcohol with a low dissolved oxygen concentration and an inert gas such as nitrogen gas is sealed, a relatively large amount of oxygen will still be present in the container. Since a certain amount of oxygen dissolves in isopropyl alcohol, it is assumed that when the dissolved oxygen reacts with isopropyl alcohol and is consumed, the oxygen in the gas phase inside the container dissolves in isopropyl alcohol and reacts with isopropyl alcohol. be done. The reaction between oxygen and isopropyl alcohol produces hydrogen peroxide as a by-product in addition to acetone, and hydrogen peroxide also reacts with isopropyl alcohol. Therefore, it is presumed that the content of organic impurities such as acetone increases due to long-term storage until most of the oxygen in the container is consumed. Furthermore, the interior of a container such as an ISO tank container is made of stainless steel or the like, and stainless steel usually contains chromium. It is presumed that due to the influence of oxygen in the container and by-produced hydrogen peroxide, the chromium contained in the stainless steel is eluted, albeit in a very small amount, and the chromium content in the isopropyl alcohol is also increased. It is assumed that the chromium eluted into isopropyl alcohol acts catalytically when oxygen reacts with isopropyl alcohol, and has the effect of promoting an increase in the content of organic impurities such as acetone during storage. It is assumed that this will bring about

Therefore, by storing isopropyl alcohol in a container and keeping the oxygen content in the container within a predetermined range when filling the gas phase with an inert gas such as nitrogen gas, metal impurities such as chromium can be prevented during long-term storage. In addition to suppressing the increase in the content of organic impurities such as chromium and acetone, it is also possible to control the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage. It is assumed that storage will be possible.

(Oxygen content in the container)
In the container of the present disclosure, the oxygen content in the container needs to be 0.001 to 0.100 molppm relative to isopropyl alcohol. From the viewpoint of suppressing the increase in the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage, the oxygen content in the container should be 0.001 to 0.050 mol ppm relative to isopropyl alcohol. It is preferably 0.001 to 0.010 molppm, more preferably 0.001 to 0.010 molppm.

The oxygen content in the container can be determined by measuring the amount of oxygen in the gas phase of the container and the amount of dissolved oxygen in isopropyl alcohol in the liquid phase, and calculating the total amount. Then, from the calculated oxygen content and the amount of isopropyl alcohol in the container, the oxygen content can be determined as a molar fraction with respect to isopropyl alcohol.

Here, the amount of oxygen in the gas phase is determined by sampling the gas phase, measuring the amount of oxygen in the sample using a known oxygen analysis method, and then calculating the amount of oxygen in the sample and the volume of the gas phase in the container. and internal pressure. Known oxygen analysis methods include gas chromatography (GC) using a pulse discharge photoionization detector, polarography, optical oxygen analysis (an analysis method that utilizes the luminescence and quenching phenomena of fluorescent substances), etc. can be mentioned.

In addition, the amount of dissolved oxygen in isopropyl alcohol in the liquid phase can be measured by sampling the isopropyl alcohol in the liquid phase and measuring the amount of oxygen in the sample using polarographic method or optical oxygen analysis (using the luminescence and quenching phenomena of fluorescent substances). It can be calculated from the amount of dissolved oxygen in the sample and the volume of isopropyl alcohol in the container.

(Content of acetone as an impurity in isopropyl alcohol)
In the container of the present disclosure, the content of acetone as an impurity in isopropyl alcohol is 10 to 200 ppb. By setting the content of acetone in isopropyl alcohol within the above range, the contained isopropyl alcohol can be suitably used as a cleaning liquid or drying liquid for semiconductor devices. From the viewpoint of reducing the influence on the device when the contained isopropyl alcohol is used as a cleaning liquid or drying liquid for semiconductor devices, the content of acetone in the isopropyl alcohol is preferably 10 to 200 ppb, and preferably 10 to 100 ppb. It is more preferable that there be.

Here, the content of acetone in isopropyl alcohol can be measured by gas chromatography-mass spectrometry (GC-MS) after sampling isopropyl alcohol in the liquid phase of the container.

(Content of chromium as an impurity in isopropyl alcohol)
As mentioned above, it is presumed that the chromium eluted into isopropyl alcohol acts catalytically when oxygen reacts with isopropyl alcohol. From the viewpoint of suppressing the increase in the content of organic impurities such as acetone during long-term storage and controlling the content of organic impurities, the content of chromium in isopropyl alcohol is preferably 0.01 to 2.50 ppt. , more preferably 0.01 to 1.00 ppt.

Here, the content of chromium in isopropyl alcohol can be measured by inductively coupled plasma mass spectrometry (ICP-MS) after sampling isopropyl alcohol in the liquid phase of the container.

(Isopropyl alcohol)
The isopropyl alcohol contained in the container is not particularly limited as long as it has the above-mentioned acetone content after being contained in the container. From the viewpoint of reducing the influence on the device when the contained isopropyl alcohol is used as a cleaning liquid or drying liquid for semiconductor devices, the purity of the isopropyl alcohol is preferably 99.99% or more, and 99.9999% or more. It is more preferable that there be. Further, from the viewpoint of suppressing the increase in content of organic impurities such as acetone during long-term storage, isopropyl alcohol that satisfies the following conditions of dissolved oxygen concentration, acetone content, and chromium content is preferable.

The dissolved oxygen concentration in isopropyl alcohol is preferably 0.001 to 0.050%, more preferably 0.001 to 0.025%, based on the oxygen saturated solubility at 25 ° C. in the atmosphere. preferable. The dissolved oxygen concentration in isopropyl alcohol is determined by measuring the amount of dissolved oxygen in the liquid phase of the container using the method described above, and measuring the oxygen partial pressure corresponding to the dissolved oxygen present in isopropyl alcohol at 25°C in the atmosphere. It can be determined by dividing the measured oxygen partial pressure by the oxygen partial pressure at 25° C. in the atmosphere and converting it into a percentage.

Here, under the atmosphere means under an air composition of 1 atmosphere. Further, the oxygen partial pressure at 25° C. in the atmosphere means the oxygen partial pressure in air at 25° C. and 1 atm, which is 21 kPa. Further, in the present disclosure, the oxygen saturated solubility at 25° C. in the atmosphere is the oxygen concentration when the dissolved oxygen is in equilibrium in an atmosphere of 1 atmosphere and oxygen partial pressure of 21 kPa.

The oxygen saturation solubility in isopropyl alcohol has different values depending on the literature. For example, see references (Sato Ten et al., "Solubility of Oxygen in Organic Solvents and Calculation of the Hansen Solubility Parameter") s of Oxygen)”, Industrial and Engineering Chemistry Research ( Ind. Eng. Chem. Res., 2014, Vol. 53, pp. 19831-19337), the oxygen saturation solubility in isopropyl alcohol at 25°C in an atmosphere with an oxygen partial pressure of 101.3 kPa is 7.78. ×10 ⁻⁴ mol/mol. When the dissolved oxygen concentration in isopropyl alcohol is 0.001 to 0.050% of the oxygen saturated solubility at 25°C in the atmosphere, the dissolved oxygen concentration in isopropyl alcohol is 0.9 to 43.5 ppb. It can be calculated as follows.

The content of acetone contained as an impurity in isopropyl alcohol is preferably 10 to 200 ppb, more preferably 10 to 100 ppb. The content of acetone in isopropyl alcohol can be measured by a method similar to the method for measuring acetone in the liquid phase portion of the container.

Among the metal impurities contained in isopropyl alcohol, the content of chromium is preferably 0.01 to 2.50 ppt, more preferably 0.01 to 1.00 ppt. The content of chromium in isopropyl alcohol can be measured by a method similar to the method for measuring chromium in the liquid phase portion of the container.

As the isopropyl alcohol contained in the container, isopropyl alcohol obtained by a known production method can be used. Known production methods include the acetone reduction method that reduces acetone, the Veba Chemie method that is a gas phase method using a fixed bed catalyst method, the Deutsche Texaco method that is a gas-liquid mixed phase method using a fixed bed catalyst method, and the direct hydration method. Can be mentioned. Among these production methods, the direct hydration method is preferred because highly pure isopropyl alcohol can be obtained and purification is easy.

A known method can be used to purify the isopropyl alcohol obtained by the above method. Specifically, examples include a method of purifying isopropyl alcohol by distillation, a method of filtering isopropyl alcohol, and a combination of these methods. When used as a cleaning liquid or drying liquid for semiconductor devices, it is necessary to use isopropyl alcohol with high purity and not containing fine particles, and it is preferable to employ a method combining distillation and filtration as the purification method.

(container of container)
As a container for storing isopropyl alcohol, any container known as a container for storing organic chemical liquids can be used without particular limitation. The volumes of these containers range, for example, from 10 to 1,500,000 L. Specifically, such containers include canisters (volume: 18-200L), intermediate bulk containers (IBC) (volume: 1000-2000L), tank trucks (volume: 2000-4000L), and ISO tank containers (volume: 13000-26000L). ), storage tanks (volume: 100,000 to 1,500,000 L), etc. In particular, as the container of the present disclosure, a container having a volume in the range of 1,000 to 1,500,000 L (intermediate bulk container, tank truck, ISO tank container, storage tank, etc.) is preferable. In such containers with a large internal volume, oxygen often remains in the gas phase when the container is filled with isopropyl alcohol and then filled with an inert gas such as nitrogen gas. In this regard, by controlling the oxygen content in the container within a predetermined range as in the present disclosure, the increase in the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage is suppressed, and It becomes possible to control the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage, allowing long-term storage from several tens of days to several months.

From the viewpoint of suppressing the increase of impurities in the isopropyl alcohol contained in the container, the materials in the parts of the container that come into contact with the isopropyl alcohol should be resins (polyolefin resin, fluororesin, etc.), glass, and metals (stainless steel, Hastelloy). , Inconel, Monel, etc.), and stainless steel is more preferable. Examples of stainless steel include SUS304 (Cr content: 18-20%, Ni content: 8-10.5%), SUS304L (Cr content: 18-20%, Ni content: 9-13%). , SUS316 (Cr content: 16-18%, Ni content: 10-14%), SUS316L (Cr content: 16-18%, Ni content: 12-15%), etc. It will be done.

As mentioned above, it is presumed that the chromium eluted into isopropyl alcohol acts catalytically when oxygen reacts with isopropyl alcohol. When using stainless steel such as SUS304 as the container material, passivation treatment must be applied to form a passive layer on the surface of the stainless steel in order to prevent metals such as chromium from eluting into isopropyl alcohol. is preferred. By applying a passivation treatment to the part that comes into contact with isopropyl alcohol, it is possible to suppress an increase in the content of metal impurities in isopropyl alcohol during storage, filling, or transportation steps. A known method can be used for the passivation treatment.

The amount of isopropyl alcohol to be stored in the container may be determined as appropriate, taking into consideration the purpose of storage, etc. Considering the volatility of isopropyl alcohol and transportation costs, it is preferable to contain isopropyl alcohol in a range of 2 to 98% of the volume of the container, and more preferably in a range of 80 to 98%. preferable.

<Method for manufacturing the container>
The method for producing a container according to the present disclosure is characterized in that when isopropyl alcohol is stored in the container, the oxygen concentration of the gas in the container is set to 0.1 to 10 volppm. This manufacturing method makes it possible to control the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage, making it possible to manufacture containers that can be stored for long periods of time ranging from tens of days to several months. is possible. From the perspective of controlling the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage, the oxygen concentration of the gas in the container when containing isopropyl alcohol should be 0.1 to 5 volppm. The amount is preferably 0.1 to 1 volppm, and even more preferably 0.1 to 0.5 volppm.

Additionally, isopropyl alcohol may be temporarily stored in a storage tank (first container) and then further stored in an ISO tank container or the like (second container). When storing isopropyl alcohol in the second container, by implementing the manufacturing method of the present disclosure described above, the isopropyl alcohol stored in the second container is also free from metal impurities such as chromium and acetone during long-term storage. It becomes possible to control the content of organic impurities such as, and enables long-term storage from several tens of days to several months.

Hereinafter, as an example of the manufacturing method of the present disclosure, a method will be described in which isopropyl alcohol that has undergone a purification process is stored in a storage tank, and the stored isopropyl alcohol is further stored in an ISO tank container.

(Storing isopropyl alcohol in a storage tank)
In the manufacturing method of the present disclosure, the storage tank is connected to a liquid sending line that sends isopropyl alcohol from the purification process to the storage tank, and a gas supply line that supplies inert gas to the storage tank. Isopropyl alcohol is contained in the storage tank via a liquid feeding line, and inert gas is sealed via a gas supply line.

As the inert gas, a stable inert gas such as nitrogen gas or argon gas can be used, and it is preferable to use nitrogen gas because inert gas with high purity can be obtained industrially at low cost. The purity of the inert gas is preferably 99.999% or more. The oxygen concentration in the inert gas is preferably 5 volppm or less, more preferably 0.5 volppm or less, and even more preferably 0.1 volppm or less.

In the manufacturing method of the present disclosure, from the viewpoint of suppressing the increase of impurities in isopropyl alcohol, the material of the transfer pipe used for the liquid feeding line and the gas supply line is preferably the same as the material of the container described above. Specifically, stainless steel or fluororesin (PFA, PTFE, etc.) is preferable. Examples of the stainless steel include SUS304, SUS304L, SUS316, and SUS316L. Stainless steel can be subjected to passivation treatment as described above.

Before sending isopropyl alcohol to the storage tank for the first time, replace the gas phase in the storage tank with inert gas, measure the oxygen concentration in the inert gas when it is filled with inert gas, After confirming that the oxygen concentration is 0.1 to 10 volppm, it is preferable to store isopropyl alcohol into the storage tank.

The dissolved oxygen concentration, acetone content, and chromium content in isopropyl alcohol when storing isopropyl alcohol into the storage tank via the liquid supply line are the dissolved oxygen concentration of isopropyl alcohol in the container described above, etc. Preferably, it is within the same preferred range.

The amount of isopropyl alcohol contained in the storage tank is preferably 2 to 98% of the volume.

Next, inert gas is sealed into the gas phase inside the storage tank containing isopropyl alcohol. The internal pressure of the gas phase within the storage tank after filling with the inert gas is not particularly limited, but is preferably 0.0001 to 0.30 MPa.

After filling with inert gas, the gas phase inside the storage tank is sampled and the oxygen concentration is measured. If the oxygen concentration is 0.1 to 10 volppm, the container can be used as the container of the present disclosure. If the oxygen concentration in the gas phase is not within the above range, the container of the present disclosure can be replaced by supplying an inert gas to replace the gas phase until the oxygen concentration in the gas phase falls within the above range. can be manufactured. Alternatively, by discharging the contained isopropyl alcohol, cleaning the inside of the storage tank, checking the airtightness of the piping (liquid feed line, gas supply line, and other equipment), and re-filling the isopropyl alcohol, the present disclosure can be carried out. body can be manufactured.

The temperature at which isopropyl alcohol is stored in the container is not particularly limited, but from the viewpoint of suppressing the increase in impurity content during long-term storage, it may be set appropriately within the range of -20 to 50°C.

(Accommodation of isopropyl alcohol in a storage tank into an ISO tank container)
Next, a method for manufacturing a container according to the present disclosure by storing isopropyl alcohol in a storage tank into an ISO tank container will be described.

A used ISO tank container may be used again as the ISO tank container. In such a case, it is preferable to co-wash the ISO tank container with isopropyl alcohol before storing the isopropyl alcohol therein.

Normally, the storage tank and the ISO tank container are not connected and are independent from each other. Therefore, in order to send isopropyl alcohol from the storage tank to the ISO tank container, a liquid delivery line for sending the isopropyl alcohol in the storage tank to the ISO tank container, and an inert gas line to the ISO tank container. Connect the transfer pipe of the gas supply line that supplies the gas.

A known method can be used to connect the ISO tank container and the transfer pipes of the liquid supply line and the gas supply line. The ISO tank container is equipped with fittings for connection with the transfer pipes of the liquid and gas supply lines. The joints provided on the transfer pipes of the liquid supply line and the gas supply line are connected to the joints provided on the ISO tank container. Types of couplings include lever type couplings, quick fluid couplings, and the like. Flexible hoses may be used for the liquid supply line and the gas supply line.

The reason why the oxygen concentration of isopropyl alcohol filled in the ISO tank container increases is when connecting the joint provided in the ISO tank container and the joint provided in the transfer pipe of the liquid supply line and the gas supply line, If the joint connection is not sealed and there is a gap, air may enter the line and oxygen may dissolve into the isopropyl alcohol in the container. Therefore, an exhaust line for venting is provided in the gas supply line, and the line is purged by pressurizing inert gas, and the atmosphere inside the gas supply line and ISO tank container is It is preferred that sufficient substitution be made.

Before filling the ISO tank container with isopropyl alcohol, it is preferable that the residual liquid of isopropyl alcohol in the ISO tank container is discharged to the outside of the ISO tank container by pressurizing an inert gas from the gas supply line.

Then, the isopropyl alcohol in the storage tank is sent into the ISO tank container via the liquid sending line. At this time, the amount of isopropyl alcohol contained in the ISO tank container is preferably 2 to 98% of the volume.

Next, an inert gas is sealed in the gas phase inside the ISO tank container filled with isopropyl alcohol. The internal pressure of the gas phase inside the ISO tank container after filling with inert gas is preferably 0.01 to 0.30 MPa, more preferably 0.02 to 0.12 MPa, and 0.02 to 0.30 MPa. More preferably, it is 0.07 MPa.

After filling with inert gas, the gas phase inside the ISO tank container is sampled and the oxygen concentration is measured. If the oxygen concentration is 0.1 to 10 volppm, the container can be used as the container of the present disclosure. If the oxygen concentration in the gas phase is not within the above range, the gas phase can be replaced by supplying an inert gas until the oxygen concentration in the gas phase falls within the above range. body can be manufactured. Alternatively, by discharging the contained isopropyl alcohol, cleaning the inside of the ISO tank container, checking the airtightness of the piping (liquid supply line, gas supply line, and other equipment), and re-accommodating the isopropyl alcohol, the present disclosure can be carried out. A container can be manufactured. The discharged isopropyl alcohol is analyzed for dissolved oxygen concentration, acetone content, and chromium content, and if all of them are within preferred ranges, it can be used as isopropyl alcohol to be stored again in the ISO tank container. On the other hand, if it is not within the preferred range, it can be purified by a known purification method and then used as isopropyl alcohol to be stored in an ISO tank container.

Although the method for transferring isopropyl alcohol in the storage tank to the ISO tank container has been described above, the manufacturing method of the present disclosure is not limited to these embodiments, and it is also possible to use a canister or the like as the container. .

Co-washing of canisters can be carried out using the following procedure. That is, co-washing is performed by filling the container with isopropyl alcohol from the liquid supply line to 1 to 10% of the volume, and after co-washing, the remaining isopropyl alcohol in the container is removed by gas supply. This can be carried out by pressurizing an inert gas from a line and discharging it out of the container. Co-washing may be performed not only once but multiple times.

Additionally, co-washing of intermediate bulk containers, tank trucks, and ISO tank containers can be carried out using the following procedure. First, pure water that has passed through a filter is supplied into the container, and the container is filled until it overflows to perform deionized water cleaning. After being left for 15 minutes, the pure water in the container is discharged out of the container by pressurizing the inert gas from the gas supply line. Co-washing is performed by filling the container with isopropyl alcohol from the liquid supply line to 1 to 10% of the volume. After co-washing, the residual liquid of isopropyl alcohol present in the container is transferred to the gas supply line. It is discharged from the container by pressurizing inert gas from the container. Co-washing may be performed not only once but multiple times. However, if the container is filled with only isopropyl alcohol and sealed with inert gas after co-washing the container multiple times, it is not necessary to perform pure water washing and co-washing of the container. .

<Quality control method for containers>
As mentioned above, if oxygen exists in the gas phase of the container, it is assumed that the content of metal impurities such as chromium and organic impurities such as acetone will increase due to long-term storage until most of the oxygen in the container is consumed. be done. For this reason, by measuring the oxygen concentration in the gas phase of the container and the dissolved oxygen concentration in isopropyl alcohol in the liquid phase and controlling it to be within a predetermined range, metal impurities such as chromium can be prevented during long-term storage. In addition to suppressing the increase in the content of organic impurities such as chromium and acetone, it is also possible to control the content of metal impurities such as chromium and organic impurities such as acetone during long-term storage. Storage becomes possible.

When measuring the oxygen concentration in the gas phase of the container, the oxygen concentration is not within the range of 0.1 to 10 volppm, or when measuring the dissolved oxygen concentration in isopropyl alcohol in the liquid phase, the dissolved oxygen concentration is 25 vol. If the oxygen saturation solubility at °C is not within the range of 0.001 to 0.050%, the following method is performed as a quality control method. First, the isopropyl alcohol in the container is discharged, and the inside of the container is purged with an inert gas. At that time, confirm that there are no leaks in the joint between the container and the transfer pipe. Next, measure the oxygen concentration in the gas phase inside the container, and after confirming that the oxygen concentration is in the range of 0.1 to 10 volppm, fill the container again with isopropyl alcohol purified by the above method. . After filling, measure the oxygen concentration in the gas phase inside the container and check that the oxygen concentration is in the range of 0.1 to 10 volppm, and measure the dissolved oxygen concentration in the isopropyl alcohol inside the container, and check that the dissolved oxygen concentration is within the range of 0.1 to 10 volppm. Below, confirm that the oxygen saturation solubility at 25°C is 0.001 to 0.050%.

Through the above procedure, the oxygen concentration in the isopropyl alcohol container can be managed. The container can suppress organic impurities in isopropyl alcohol and an increase in chromium content even during storage or transportation. The isopropyl alcohol in the container can be stored for a long time and can be suitably used as a cleaning liquid or drying liquid for semiconductor devices.

Note that the isopropyl alcohol in the container can suppress an increase in not only the acetone content but also the content of organic acids and the like among organic impurities.

Hereinafter, the present invention will be explained in detail using Examples, but the present invention is not limited to these Examples.

<Oxygen content in isopropyl alcohol container>
The oxygen content in the gas phase of the isopropyl alcohol container was calculated as follows. First, using an optical oxygen concentration meter (manufactured by PreSens, Fibox 4 trace (sensor: Pst6)), nitrogen with a purity of 99.999% or more and an oxygen concentration of 1 volppm or less, and nitrogen whose oxygen concentration was adjusted to 1000 volppm was measured and calibrated in advance. Next, the value of the internal pressure of the gas phase of the container is confirmed from the pressure gauge installed in the container, and the gas phase of the container is pumped to the optical oxygen concentration meter using the internal pressure of the gas phase of the container. Then, purging was performed for 1 minute, and the oxygen concentration in the gas phase of the container was measured. Finally, the amount of oxygen in the gas phase of the container is calculated from the formula: (Oxygen concentration in the gas phase of the container × (atmospheric pressure + internal pressure) ÷ atmospheric pressure × molar volume of gas × volume of gas phase) did.

In addition, the amount of oxygen in the liquid phase in the container was calculated as follows. First, using an optical oxygen concentration meter (manufactured by PreSens, Fibox 4 trace (sensor: Pst6)), nitrogen with a purity of 99.999% or more and an oxygen concentration of 1 volppm or less, and nitrogen whose oxygen concentration was adjusted to 1000 volppm was measured and calibrated in advance. Next, the liquid phase portion of the container was force-fed to the optical oxygen concentration meter by the internal pressure of the gas phase portion of the container, purging was performed for 1 minute, and the oxygen concentration in the liquid phase portion of the container was measured. Finally, the amount of oxygen in the liquid phase portion of the container was calculated from the formula (oxygen concentration in the liquid phase portion of the container/molar mass of oxygen×weight of the liquid phase).

The total amount of oxygen in the gas phase and liquid phase of the container was defined as the oxygen content in the container. The molar fraction of the oxygen content in the container with respect to isopropyl alcohol was calculated from the formula (oxygen content in the container÷weight of liquid phase×molar mass of isopropyl alcohol).

<Acetone content in isopropyl alcohol container>
The acetone content in the isopropyl alcohol container was measured by selected ion detection method (SIM) using GC-MS (gas chromatography mass spectrometry) under the measurement conditions shown below. Create a calibration curve for the acetone content under the same measurement conditions in advance, determine the acetone content in the measured sample based on the calibration curve, convert it to the amount of isopropyl alcohol in the container, and calculate the amount of isopropyl alcohol in the container. The acetone content in
-Measurement condition-
Equipment: GCMS-QP2010 Ultra (manufactured by Shimadzu Corporation)
Column: CP-WAX 52CB (60m x 0.25mm, 0.50μm)
Carrier gas: Helium Carrier gas flow rate: 0.98mL/min Inlet temperature: 150℃
Column temperature: 75℃
Detector temperature: 230℃
Injection mode: Split method Split ratio: 1:10
SIM mode set ion: m/Z=43

<Chromium content in isopropyl alcohol container>
Metal impurities contained in isopropyl alcohol were quantified using ICP-MS (inductively coupled plasma mass spectrometry) as follows. Approximately 500 mL of isopropyl alcohol was collected in an eggplant-shaped flask, concentrated and dried using a rotary evaporator, and then collected in two portions with approximately 25 mL of 0.1N nitric acid. The amount of metal eluted from the recovered 0.1N nitric acid solution was determined using ICP-MS (Agilent 8900, manufactured by Agilent Technologies). At this time, the concentration ratio was calculated from the ratio of the weight of isopropyl alcohol before concentration and the weight of 0.1N nitric acid solution after recovery, and converted to the amount of metal impurities per weight of isopropyl alcohol.

<Example 1>
The isopropyl alcohol that had undergone the purification process was stored in a storage tank using the following method. First, before feeding isopropyl alcohol to the storage tank, the inside of the storage tank was replaced with nitrogen via the gas supply line. The purity of the nitrogen used at this time was 99.999% or more, and the oxygen concentration was 5 volppm or less. After the gas phase replacement, the oxygen content in the container was measured, and the oxygen concentration in the gas phase in the storage tank was 1 vol ppm or less. Next, the isopropyl alcohol that had undergone the purification process was stored in the storage tank via the liquid feeding line. The amount of isopropyl alcohol contained in the storage tank was 80% of the internal volume. Next, the gas phase in the storage tank containing isopropyl alcohol was filled with nitrogen via a gas supply line. The internal pressure of the gas phase in the storage tank after nitrogen filling was 0.0005 MPa.

After sealing nitrogen into the gas phase in the storage tank to create an isopropyl alcohol container, the oxygen content in the container was measured, and the oxygen concentration in the gas phase of the container was 1.0 volppm, indicating that the container contained The dissolved oxygen concentration of isopropyl alcohol in the body is 0.024% with respect to the oxygen saturated solubility at 25°C in the atmosphere, and the molar fraction of the oxygen content in the container with respect to isopropyl alcohol is 0.040 mol ppm. there were. Further, the acetone content in the container was 10 ppb, and the chromium content was 0.19 ppt.

The container thus produced was stored at a temperature range of 15 to 30°C for 30 days. After storage, we measured the oxygen content in the container and found that the oxygen concentration in the gas phase in the container was 0.7 volppm, and the dissolved oxygen concentration of isopropyl alcohol in the container was 0.7 volppm in the atmosphere at 25°C. The oxygen saturation solubility was 0.016%, and the molar fraction of oxygen content in the container relative to isopropyl alcohol was 0.027 mol ppm. Further, the acetone content in the container was 46 ppb, and the chromium content was 0.64 ppt.

<Comparative example 1>
The isopropyl alcohol that had undergone the purification process was stored in a storage tank using the following method. First, isopropyl alcohol that had undergone a purification process was placed in a storage tank via a liquid feeding line. The amount of isopropyl alcohol contained in the storage tank was 80% of the internal volume. Next, the gas phase in the storage tank containing isopropyl alcohol was filled with nitrogen via a gas supply line. The purity of the nitrogen used at this time was 99.999% or more, and the oxygen concentration was 5 volppm or less. The internal pressure of the gas phase in the storage tank after nitrogen filling was 0.0005 MPa.

The container thus produced was stored in a temperature range of 15 to 30°C for 51 days. Table 1 shows the storage conditions of the container, and Table 2 shows the oxygen content, acetone content, and chromium content in the container before and after storage.

<Example 2>
The isopropyl alcohol in the storage tank was placed into the ISO tank container in the following manner. First, the joints provided on the transfer pipes of the liquid and gas supply lines connected to the storage tank were connected to the joints of the ISO tank container. The line was purged for 5 minutes by applying nitrogen pressure to the vent exhaust line in the gas supply line. The purity of the nitrogen used at this time was 99.999% or more, and the oxygen concentration was 5 volppm or less. It was also confirmed that there were no leaks at the joints of the transfer pipes. After the gas phase replacement, it was confirmed that the oxygen concentration in the gas supply line was 1 volppm or less. Next, before sending isopropyl alcohol to the ISO tank container, the remaining isopropyl alcohol in the ISO tank container was discharged outside the ISO tank container by pressurizing nitrogen from the gas supply line. After discharging isopropyl alcohol, it was confirmed that the oxygen concentration in the gas phase in the ISO tank container was 1 volppm or less. Next, the isopropyl alcohol in the storage tank was placed in the ISO tank container via the liquid feed line. The amount of isopropyl alcohol contained in the ISO tank container was 87% of the internal volume. Next, nitrogen was sealed into the gas phase portion of the ISO tank container containing isopropyl alcohol via a gas supply line. The internal pressure of the gas phase in the ISO tank container after nitrogen filling was 0.07 MPa.

The container thus produced was stored for 20 days in a temperature range of 15 to 30°C. Table 1 shows the storage conditions of the container, and Table 2 shows the oxygen content, acetone content, and chromium content in the container before and after storage.

<Comparative example 2>
The isopropyl alcohol in the storage tank was placed into the ISO tank container in the following manner. First, the joints provided on the transfer pipes of the liquid and gas supply lines connected to the storage tank were connected to the joints of the ISO tank container. However, the inside of the line was not purged by nitrogen pressurization. Next, before sending the isopropyl alcohol to the ISO tank container, the remaining isopropyl alcohol in the ISO tank container was discharged outside the ISO tank container for 1 minute by pressurizing nitrogen from the gas supply line. The purity of the nitrogen used at this time was 99.999% or more, and the oxygen concentration was 5 volppm or less. Next, the isopropyl alcohol in the storage tank was placed in the ISO tank container via the liquid feed line. The amount of isopropyl alcohol contained in the ISO tank container was 87% of the internal volume. Next, nitrogen was sealed into the gas phase portion of the ISO tank container containing isopropyl alcohol via a gas supply line. The internal pressure of the gas phase in the ISO tank container after nitrogen filling was 0.06 MPa.

The container thus produced was stored for 21 days in a temperature range of 15 to 30°C. Table 1 shows the storage conditions of the container, and Table 2 shows the oxygen content, acetone content, and chromium content in the container before and after storage.

<Example 3>
The isopropyl alcohol in the storage tank was placed into a canister in the following manner. First, the joints provided on the transfer pipes of the liquid and gas supply lines connected to the storage tank were connected to the joints of the canister. Co-washing is performed by filling isopropyl alcohol into the canister to a volume of 1 to 10% through the liquid supply line, and after co-washing, remove the remaining isopropyl alcohol in the canister. , and was discharged out of the container by pressurizing nitrogen from the gas supply line. Co-washing was carried out three times. The purity of the nitrogen used at this time was 99.999% or more, and the oxygen concentration was 5 volppm or less. It was also confirmed that there were no leaks at the joints of the transfer pipes. After co-washing, it was confirmed that the oxygen concentration inside the canister was 1 volppm or less. Next, the isopropyl alcohol in the storage tank was placed in the canister via the liquid feed line. The amount of isopropyl alcohol contained in the canister was 82% of the internal volume. Next, the gas phase in the canister containing isopropyl alcohol was filled with nitrogen via a gas supply line. The internal pressure of the gas phase in the canister after nitrogen filling was 0.20 MPa.

The container thus produced was stored for 59 days in a temperature range of 15 to 30°C. Table 1 shows the storage conditions of the container, and Table 2 shows the oxygen content, acetone content, and chromium content in the container before and after storage.

<Comparative example 3>
The isopropyl alcohol in the storage tank was placed into a canister in the following manner. First, the joints provided on the transfer pipes of the liquid and gas supply lines connected to the storage tank were connected to the joints of the canister. Co-washing is performed by filling isopropyl alcohol into the canister to a volume of 1 to 10% through the liquid supply line, and after co-washing, remove the remaining isopropyl alcohol in the canister. , and was discharged out of the container by pressurizing nitrogen from the gas supply line. Co-washing was carried out three times. The purity of the nitrogen used at this time was 99.999% or more, and the oxygen concentration was 5 volppm or less. It was also confirmed that there were no leaks at the joints of the transfer pipes. After co-washing, it was confirmed that the oxygen concentration inside the canister was 1 volppm or less. Next, the isopropyl alcohol in the storage tank was placed in the canister via the liquid feed line. The amount of isopropyl alcohol contained in the canister was 82% of the internal volume. Next, the gas phase in the canister containing isopropyl alcohol was filled with nitrogen via a gas supply line, and the internal pressure inside the canister was set to 0.05 MPa. Further, nitrogen having an oxygen concentration of 1000 volppm was sealed, and the internal pressure of the gas phase in the canister after nitrogen filling was set to 0.20 MPa.

<Example 4>
The isopropyl alcohol in the storage tank was placed into the ISO tank container in the following manner. First, the joints provided on the transfer pipes of the liquid and gas supply lines connected to the storage tank were connected to the joints of the ISO tank container. The line was purged for 5 minutes by applying nitrogen pressure to the vent exhaust line in the gas supply line. The purity of the nitrogen used at this time was 99.999% or more, and the oxygen concentration was 5 volppm or less. It was also confirmed that there were no leaks at the joints of the transfer pipes. After the gas phase replacement, it was confirmed that the oxygen concentration in the gas supply line was 1 volppm or less. Next, before sending isopropyl alcohol to the ISO tank container, the remaining isopropyl alcohol in the ISO tank container was discharged outside the ISO tank container by pressurizing nitrogen from the gas supply line. After discharging isopropyl alcohol, it was confirmed that the oxygen concentration in the gas phase in the ISO tank container was 1 volppm or less. Next, the isopropyl alcohol in the storage tank was placed in the ISO tank container via the liquid feed line. The amount of isopropyl alcohol contained in the ISO tank container was 87% of the internal volume. Next, nitrogen was sealed into the gas phase portion of the ISO tank container containing isopropyl alcohol via a gas supply line. The internal pressure of the gas phase in the ISO tank container after nitrogen filling was 0.05 MPa.

The container thus produced was stored at a temperature range of 15 to 30°C for 98 days. Table 1 shows the storage conditions of the container, and Table 2 shows the oxygen content, acetone content, and chromium content in the container before and after storage.

<Example 5>
The isopropyl alcohol in the storage tank was placed into the ISO tank container in the following manner. First, the joints provided on the transfer pipes of the liquid and gas supply lines connected to the storage tank were connected to the joints of the ISO tank container. The line was purged for 5 minutes by applying nitrogen pressure to the vent exhaust line in the gas supply line. The purity of the nitrogen used at this time was 99.999% or more, and the oxygen concentration was 5 volppm or less. It was also confirmed that there were no leaks at the joints of the transfer pipes. After the gas phase replacement, it was confirmed that the oxygen concentration in the gas supply line was 5 volppm or less. Next, before sending isopropyl alcohol to the ISO tank container, the remaining isopropyl alcohol in the ISO tank container was discharged outside the ISO tank container by pressurizing nitrogen from the gas supply line. After discharging isopropyl alcohol, it was confirmed that the oxygen concentration in the gas phase in the ISO tank container was 5 volppm or less. Next, the isopropyl alcohol in the storage tank was placed in the ISO tank container via the liquid feed line. The amount of isopropyl alcohol contained in the ISO tank container was 87% of the internal volume. Next, nitrogen was sealed into the gas phase portion of the ISO tank container containing isopropyl alcohol via a gas supply line. The internal pressure of the gas phase in the ISO tank container after nitrogen filling was 0.05 MPa.

The container thus produced was stored for 35 days at a temperature range of 15 to 30°C. Table 1 shows the storage conditions of the container, and Table 2 shows the oxygen content, acetone content, and chromium content in the container before and after storage.

As shown in Table 2, an example in which the oxygen content in the container was set to 0.001 to 0.100 molppm relative to isopropyl alcohol, and the content of acetone as an impurity in isopropyl alcohol was set to 10 to 200 ppb on a mass basis. In the containers Nos. 1 to 5, increases in acetone content and chromium content after long-term storage of several tens of days to several months were suppressed compared to the containers of Comparative Examples 1 to 3.

Claims

An isopropyl alcohol container in which isopropyl alcohol is stored in a container,
The oxygen content in the container is 0.001 to 0.100 molppm relative to the isopropyl alcohol,
The isopropyl alcohol container has a content of acetone as an impurity in the isopropyl alcohol of 10 to 200 ppb on a mass basis.
The isopropyl alcohol container according to claim 1, wherein the content of chromium as an impurity in the isopropyl alcohol is 0.01 to 2.50 ppt on a mass basis.
The isopropyl alcohol container according to claim 1 or 2, wherein the volume of the container is in the range of 1,000 to 1,500,000 L.
The isopropyl alcohol container according to claim 3, wherein the container is an intermediate bulk container, a tank truck, an ISO tank container, or a storage tank.
A method for producing an isopropyl alcohol container in which isopropyl alcohol is contained in a container, the method comprising:
A method for producing an isopropyl alcohol container, in which when isopropyl alcohol is stored in the container, the oxygen concentration of the gas in the container is 0.1 to 10 ppm on a volume basis.
The isopropyl alcohol container according to claim 5, wherein the dissolved oxygen concentration in the isopropyl alcohol contained in the container is 0.001 to 0.050% with respect to the oxygen saturated solubility at 25 ° C. in the atmosphere. Production method.
The method for producing an isopropyl alcohol container according to claim 5 or 6, wherein the content of acetone as an impurity in the isopropyl alcohol contained in the container is 10 to 200 ppb on a mass basis.
The method for producing an isopropyl alcohol container according to claim 5 or 6, wherein the content of chromium as an impurity in the isopropyl alcohol contained in the container is 0.01 to 2.50 ppt on a mass basis.
The method for producing an isopropyl alcohol container according to claim 5 or 6, wherein the volume of the container is in the range of 1,000 to 1,500,000 L.
The method for producing an isopropyl alcohol container according to claim 9, wherein the container is an intermediate bulk container, a tank truck, an ISO tank container, or a storage tank.
A method for producing an isopropyl alcohol container in which isopropyl alcohol is contained in a container, the method comprising:
The isopropyl alcohol is contained in an amount of 2 to 98% of the volume of the container,
A method for producing an isopropyl alcohol container, in which when isopropyl alcohol is stored in the container, the oxygen concentration of the gas in the container is 0.1 to 10 ppm on a volume basis.
The isopropyl alcohol container according to claim 11, wherein the dissolved oxygen concentration in the isopropyl alcohol contained in the container is 0.001 to 0.050% with respect to the oxygen saturated solubility at 25 ° C. in the atmosphere. Production method.
The method for producing an isopropyl alcohol container according to claim 11 or 12, wherein the content of acetone as an impurity in the isopropyl alcohol contained in the container is 10 to 200 ppb on a mass basis.
The method for producing an isopropyl alcohol container according to claim 11 or 12, wherein the content of chromium as an impurity in the isopropyl alcohol contained in the container is 0.01 to 2.50 ppt on a mass basis.
The method for producing an isopropyl alcohol container according to claim 11 or 12, wherein the volume of the container is in the range of 1,000 to 1,500,000 L.
The method for producing an isopropyl alcohol container according to claim 15, wherein the container is an intermediate bulk container, a tank truck, an ISO tank container, or a storage tank.
A method for producing an isopropyl alcohol container in which isopropyl alcohol contained in a first container is stored in a second container, the method comprising:
A method for producing an isopropyl alcohol container, in which when isopropyl alcohol is stored in the second container, the oxygen concentration of the gas in the second container is 0.1 to 10 ppm on a volume basis.
The isopropyl alcohol according to claim 17, wherein the dissolved oxygen concentration in the isopropyl alcohol contained in the second container is 0.001 to 0.050% with respect to the oxygen saturated solubility at 25° C. in the atmosphere. Method for manufacturing a container.
The method for producing an isopropyl alcohol container according to claim 17 or 18, wherein the content of acetone as an impurity in the isopropyl alcohol contained in the second container is 10 to 200 ppb on a mass basis.
The method for producing an isopropyl alcohol container according to claim 17 or 18, wherein the content of chromium as an impurity in the isopropyl alcohol contained in the second container is 0.01 to 2.50 ppt on a mass basis.
The method for producing an isopropyl alcohol container according to claim 17 or 18, wherein the volume of the container is in the range of 1,000 to 1,500,000 L.
The method for producing an isopropyl alcohol container according to claim 21, wherein the container is an intermediate bulk container, a tank truck, an ISO tank container, or a storage tank.
A quality control method for an isopropyl alcohol container in which isopropyl alcohol is stored in a container, the method comprising:
The dissolved oxygen concentration in the isopropyl alcohol is 0.001 to 0.050% with respect to the oxygen saturated solubility at 25 ° C. in the atmosphere, and the oxygen concentration of the gas in the container is 0.1 on a volume basis. A quality control method for an isopropyl alcohol container with a concentration of ~10 ppm.