JPH09278416A - Production of high purity hydrogen peroxide solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase purity by bringing a hydrogen peroxide soln. into contact with a specified ion exchange resin layer, cooling to precipitate a solid phase and then fusing the separated solid phase. SOLUTION: A hydrogen peroxide soln. containing 10 to 70wt.% hydrogen peroxide is brought into contact with at least two kinds of resin layers at <=30 deg.C. There resin layers are prepared by selecting from a cation exchange resin having a SO3 H group as an ion exchange group, an anion exchange resin having carbonate or bicarbonate of quaternary ammonium groups, and a mixture of a cation exchange resin and an anion exchange resin with 3:97 to 97:3 mixing ratio. Then the hydrogen peroxide soln. is concentrated or diluted to control the concn. of hydrogen peroxide to 45.2 to 61.2wt.%. Then, if necessary, a seed crystal is added by 0.5 to 1g per 1L hydrogen peroxide soln., and the obtd. soln. is cooled to -0.5 to -56.1 deg.C to precipitate a solid phase. The solid phase is separated from the liquid phase and then fused.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cationic impurity,
The present invention relates to a method for purifying an aqueous hydrogen peroxide solution containing anionic impurities and organic impurities to obtain an extremely high-purity aqueous hydrogen peroxide solution. The highly pure aqueous hydrogen peroxide solution purified according to the present invention is used in the semiconductor field.

[0002]

2. Description of the Related Art At present, an aqueous solution of hydrogen peroxide is mainly produced by an anthraquinone auto-oxidation method (hereinafter sometimes referred to as an anthraquinone method). This method is generally
2-Alkylanthraquinone is hydrogenated in the presence of a hydrogenation catalyst in an organic solvent to give the corresponding anthrahydroquinone, and the catalyst is filtered off and then oxidized with oxygen or air to regenerate the anthrahydroquinone to a 2-alkylanthraquinone. A crude hydrogen peroxide aqueous solution is obtained by producing hydrogen peroxide and extracting the produced hydrogen peroxide with water. The obtained aqueous hydrogen peroxide solution is purified and concentrated by distillation under reduced pressure and rectification. Then, it is diluted with water to a predetermined concentration in some cases, and generally about 20-70.
An aqueous solution containing hydrogen peroxide in weight% is used.

The aqueous hydrogen peroxide solution produced by such a method contains various cations of about 5 ppb to about 10 ppm and about 10 ppb to about 10 ppm due to elution from a production apparatus or storage apparatus and addition of a stabilizer. Various anions, further, organic substances used in the anthraquinone method, or contaminants thereof are mixed, and organic impurities of about 10 ppm to several 100 ppm are contained as the total amount of organic carbon.

On the other hand, the aqueous hydrogen peroxide solution has hitherto been widely used in the fields of reaction reagents, bleaching, chemical polishing and the like.
In recent years, in the field of semiconductor manufacturing, the use of hydrogen peroxide aqueous solution has increased in the fields of wafer cleaning, etching, and the like, and accordingly, an extremely high-purity hydrogen peroxide aqueous solution is required.

As a method for purifying an aqueous hydrogen peroxide solution, generally, a method for removing cationic impurities by using a cation exchange resin, a method for removing anionic impurities by using an anion exchange resin, and a method for removing organic impurities by using an adsorbent are used. A method of removing, and a method of removing cationic impurities, anionic impurities, and organic impurities by combining these methods are known.

For example, in JP-A-1-17105, a bicarbonate type or carbonate type anion exchange resin is used, and an acid having a dissociation index pKa in water of 5 or less or a salt thereof is continuously or anti-continuously added. However, it is described that anionic impurities are removed.

US Pat. No. 5,268,160 describes a method of contacting an aqueous hydrogen peroxide solution with an adsorbing resin such as a styrene polymer to remove organic impurities. Japanese Patent Laid-Open No. 63-156004 describes a method of removing organic impurities by bringing an aqueous hydrogen peroxide solution into contact with a halogen-containing porous resin.

In US Pat. No. 4,999,179, a cation exchange resin layer, a halogen-containing porous resin layer and an anion exchange resin layer are provided in this order, or a halogen-containing porous resin layer, a cation exchange resin layer and an anion exchange resin layer. It is possible to remove cationic impurities, anionic impurities, and organic impurities by contacting hydrogen peroxide in the order of the resin layer, or in the order of the halogen-containing porous resin layer and the mixed layer of the cation exchange resin / anion exchange resin. It is written.

However, in the purification by the conventional method as described above, the cationic impurities or the anionic impurities can achieve the desired impurity concentration, but the cationic impurities, the anionic impurities and the organic impurities are all removed. Desired concentration, ie, 0.5 ppb or less of cationic impurities and 10 ppb of anionic impurities
Below, and organic impurities are 3ppm as the total amount of organic carbon
It was extremely difficult to obtain a highly pure aqueous hydrogen peroxide solution satisfying the following conditions.

[0010]

DISCLOSURE OF THE INVENTION The present invention removes impurities in an aqueous hydrogen peroxide solution with high efficiency and safely,
It is to provide a highly pure aqueous hydrogen peroxide solution.

[0011]

According to the present invention, an aqueous solution of hydrogen peroxide containing 10 to 70% by weight of hydrogen peroxide is mixed with a cation exchange resin layer, an anion exchange resin layer, and a cation exchange resin / anion exchange resin mixture. After contact with at least two different layers selected from the group consisting of layers, the hydrogen peroxide concentration is adjusted to a concentration of at least 45.2% by weight, which is from -0.5 ° C to -56.1. It is a method for producing a high-purity hydrogen peroxide aqueous solution, which comprises cooling at a temperature of ° C to precipitate a solid phase, and melting the obtained solid phase.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the method of the present invention, an aqueous hydrogen peroxide solution containing at least 10 to 70% by weight of hydrogen peroxide is used as the starting aqueous hydrogen peroxide solution. Particularly preferred is an aqueous hydrogen peroxide solution containing 20 to 60% by weight of hydrogen peroxide.

In the present invention, the raw hydrogen peroxide solution is contacted with at least two different layers selected from the group consisting of a cation exchange resin layer, an anion exchange resin layer, and a cation exchange resin / anion exchange resin mixed layer. And then refined. The arrangement order of these resin layers is not particularly limited, but it is preferable to finally contact the resin layers with the anion exchange resin or the cation exchange resin / anion exchange resin mixed layer.

As the cation exchange resin used in the present invention, one having an SO ₃ H group as an ion exchange group is used, but a resin having a strong acidity and a high crosslinking property is preferable. Such a cation exchange resin is, for example, manufactured by Organo Co., Ltd., trade name; Amberlite 200C, Amberlite 200CT, Amberlite 252 or Mitsubishi Chemical Co., Ltd., trade name; Diaion PK series (eg PK224, PK228. ) And the like.

The temperature at which the hydrogen peroxide solution is brought into contact with the cation exchange resin layer is about 30 ° C. or lower, preferably -10.
The range of -20 ° C is preferred. If it exceeds 30 ° C., the ratio of ion exchange groups (SO ₃ H groups) to be eluted increases, which is not preferable.

The anion exchange resin used in the present invention is preferably a resin that is strongly basic and highly crosslinkable. Such anion exchange resin is a strongly basic resin having a quaternary ammonium group,
It may be a weakly basic resin having a quaternary ammonium group or a vinylpyridine resin, but is preferably a strongly basic resin having a quaternary ammonium group, and particularly preferably a carbonate or a heavy salt of a quaternary ammonium group. It is a resin containing carbonate.

Such anion exchange resin is, for example,
Organo Co., Ltd., trade name; Amberlite IRA series (for example, IRA-900, IRA-904),
Mitsubishi Kagaku Co., Ltd. product name; PA series (for example, PA316, PA318) of Diaion, etc. are mentioned.

The temperature at which the aqueous hydrogen peroxide solution is brought into contact with the anion exchange resin layer is about 10 ° C. or lower, preferably -10.
A range of 5 ° C to 5 ° C is suitable. If it exceeds 10 ° C, hydrogen peroxide is likely to be decomposed, which is not preferable.

When a mixed layer of cation exchange resin and anion exchange resin is used, the volume ratio of both is 3: 97-9.
It is preferable to mix and use it so that it may become 7: 3.

In the present invention, the aqueous solution of hydrogen peroxide after the contact treatment with the cation exchange resin layer, the anion exchange resin layer and the cation exchange resin / anion exchange resin mixed layer is directly or, if necessary, concentrated or diluted. The solid phase is prepared by adjusting the concentration to at least 45.2% by weight.

The solid phase precipitation operation is used as an aqueous hydrogen peroxide solution containing at least 45.2% by weight hydrogen peroxide. Although the use of an aqueous hydrogen peroxide solution containing hydrogen peroxide at a concentration of over 61.2% by weight is effective for purification of the aqueous hydrogen peroxide solution, hydrogen peroxide crystals, that is, 100% by weight of hydrogen peroxide Since it precipitates as crystals, handling becomes difficult. The use of an aqueous hydrogen peroxide solution containing 45.2 to 61.2% by weight of hydrogen peroxide is preferable in terms of handling, since a hydrate of hydrogen peroxide is deposited as crystals.

On the other hand, in the case of an aqueous solution of hydrogen peroxide containing hydrogen peroxide at a concentration of less than 45.2% by weight, water crystals are precipitated as a solid phase. It has no effect on purification.

In depositing the solid phase, it is preferable to add a solid phase having the same hydrogen peroxide concentration as the deposited solid phase as a seed crystal. Seed crystals can be added in very small amounts, 1
0.5 to 1 g per liter of raw material hydrogen peroxide solution
Degree is fine. The temperature at which the seed crystal is added is lower than the freezing point temperature in the raw material hydrogen peroxide aqueous solution concentration,
And it is preferable that the temperature difference is small. In order to remove impurities more effectively, it is more preferable that the temperature difference be within 5 ° C.

It is preferable to reduce the rate of solid phase formation when the solid phase is deposited. The smaller the solid phase generation rate, the smaller the amount of impurities contained in the solid phase, and the higher the purification effect. However, when the generation rate of the solid phase is below a certain level, metal impurities such as Fe and Cr are likely to be contained in the solid phase, and the concentration thereof tends to increase. Further, if the production facilities have the same capacity, if the solid phase production rate is reduced, the production amount per unit time decreases, which is not preferable from an industrial viewpoint.

On the other hand, when the solid phase production rate increases, the production amount per unit time increases, but the efficiency of removing impurities decreases, which is not preferable. From these facts, the solid phase generation rate is 18 to 150 g / liter-raw material hydrogen peroxide aqueous solution.
It is preferable to set it as hr, More preferably, it is 60-15.
0 g / liter-a raw material hydrogen peroxide aqueous solution.

The solid phase produced is separated from the liquid phase. Any method may be used for separating the produced solid phase from the liquid phase, but since impurities are concentrated in the liquid phase,
A method in which it adheres to the solid phase is not preferred. Generally, a separation method using a centrifugal dehydrator is suitable.

It is also effective to remove the mother liquor adhering to the solid phase by washing the generated solid phase obtained by separation from the liquid phase with a highly pure aqueous hydrogen peroxide solution.

The aqueous solution of hydrogen peroxide used as a raw material in the present invention is preferably one prepared by the anthraquinone method, but is not limited to the aqueous solution of hydrogen peroxide prepared by the anthraquinone method and may be one prepared by another method. .

[0029]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

For measuring metallic impurities, Ca was used for flameless atomic absorption spectrometry, and otherwise, ICP-MS (Induct) was used.
icvely coupled plasma Mas
According to the ssspectrometry method.

The anionic impurities were measured by the ion chromatography method. Raw materials and organic impurities were measured as total organic carbon content using a total organic carbon meter. The impurities in the hydrogen peroxide aqueous solution used as the raw material were measured by diluting with purified water to 31% by weight.

Example 1 A raw material hydrogen peroxide aqueous solution was diluted with purified water to 31% by weight and then, at 1000 ml / hr, a cation exchange resin packed column, an anion exchange resin packed column, a mixture of a cation exchange resin and an anion exchange resin. The solution was passed through the column filled with the resin in this order. Each packed column has an inner diameter of 20
A column tube made of fluororesin having a diameter of mmφ was filled with 20 ml of ion exchange resin. The cation exchange resin used here is a trade name; Diaion PK228LH (manufactured by Mitsubishi Chemical Co., Ltd.), and the anion exchange resin is a trade name; Diaion PA318HCO ₃ (manufactured by Mitsubishi Chemical Co., Ltd.). DIAION PK228LH and DIAION PA318HC are used in the mixed layer with the exchange resin.
A resin mixture was used in which O ₃ was thoroughly mixed at a volume ratio of 1: 1.

Then, the obtained aqueous hydrogen peroxide solution is added to 5
After concentrating to 5% by weight and putting 2200 g as a raw material in a stainless steel container having an internal volume of 2 L and cooling the aqueous solution to −53 ° C. while stirring, about 0.5 g of hydrogen peroxide hydrate crystal was used as a seed crystal. Then, a small amount of hydrogen peroxide hydrate crystals was precipitated in the hydrogen peroxide aqueous solution. Furthermore, the production rate of the solid phase was adjusted to 60 g / liter-raw material hydrogen peroxide aqueous solution · hr, and cooling was continued until the temperature of the aqueous solution reached −54.5 ° C. Next, an operation of separating the solid phase and the liquid phase by putting an aqueous hydrogen peroxide solution in which the solid phase and the liquid phase coexist into a basket type centrifugal dehydrator while melting some crystals. The obtained solid phase was melted to obtain 550 g of an aqueous hydrogen peroxide solution containing 48.8% by weight of hydrogen peroxide.

The content of impurities after purification is as shown in Table 1. Cationic impurities of 0.5 ppb or less, anionic impurities of 10 ppb or less, and organic impurities of 3 ppm or less were achieved.

Example 2 The raw material hydrogen peroxide aqueous solution was diluted with purified water to 31% by weight and then passed through a cation exchange resin packed column and an anion exchange resin packed column in this order at 1000 ml / hr. Each packed column was prepared by packing 20 ml of ion exchange resin into a fluororesin column tube having an inner diameter of 20 mmφ. The cation exchange resin used here is a trade name; Diaion PK228LH (Mitsubishi Chemical Corporation)
Made), anion exchange resin is a trade name; Diaion PA3
18HCO ₃ (manufactured by Mitsubishi Chemical Corporation).

Next, the obtained hydrogen peroxide aqueous solution is added to 5
After concentrating to 5% by weight and putting 2200 g as a raw material in a stainless steel container having an internal volume of 2 L and cooling the aqueous solution to −53 ° C. while stirring, about 0.5 g of hydrogen peroxide hydrate crystal was used as a seed crystal. Then, a small amount of hydrogen peroxide hydrate crystals was precipitated in the hydrogen peroxide aqueous solution. Furthermore, the production rate of the solid phase was adjusted to 60 g / liter-raw material hydrogen peroxide aqueous solution · hr, and cooling was continued until the temperature of the aqueous solution reached −54.5 ° C. Subsequently, an operation of separating the solid phase and the liquid phase by putting a hydrogen peroxide aqueous solution in which the solid phase and the liquid phase coexist in a basket type centrifugal dehydrator to melt some crystals. The obtained solid phase was melted to obtain 550 g of an aqueous hydrogen peroxide solution containing 48.8% by weight of hydrogen peroxide.

The content of impurities after purification is as shown in Table 1. Cationic impurities of 0.5 ppb or less, anionic impurities of 10 ppb or less, and organic impurities of 3 ppm or less were achieved.

Example 3 Purification was carried out in the same manner as in Example 1 except that the solid phase production rate was 18 g / liter-raw material hydrogen peroxide solution / hr. The content of impurities after purification is as shown in Table 1. Cationic impurities are 0.5 ppb or less, anion impurities are 10 ppb or less, and organic impurities are 3 p as total organic carbon amount.
pm or less was achieved.

Comparative Example 1 The same raw material hydrogen peroxide aqueous solution as that used in Example 1 was diluted with purified water to 31% by weight, and then 1000 ml / hr.
Then, the solution was passed through the cation exchange resin packed column, the anion exchange resin packed column, and the column packed with the mixture of the cation exchange resin and the anion exchange resin in this order. The same ion exchange packed column as in Example 1 was used.

The content of impurities after purification is as shown in Table 1. Cationic impurities of 0.5 ppb or less and anionic impurities of 10 ppb or less were achieved, but organic impurities were 3 ppm or less in total organic carbon content. I couldn't achieve it.

Comparative Example 2 The same raw material hydrogen peroxide aqueous solution as that used in Example 1 was diluted with purified water to 31% by weight, and then 1000 ml / hr.
Then, the solution was passed through the cation exchange resin packed column, the anion exchange resin packed column, and the column packed with the mixture of the cation exchange resin and the anion exchange resin in this order. The same ion exchange packed column as in Example 1 was used. Then, an operation of adsorbing and removing the organic matter was carried out by passing the obtained hydrogen peroxide aqueous solution through a column filled with an adsorption resin. The adsorption resin packed column was prepared by filling 10 ml of a fluororesin column tube having an inner diameter of 10 mm with a porous resin of brominated styrene-divinylbenzene copolymer as an adsorbent and trade name: SepaBeads SP207 (Mitsubishi Chemical Co., Ltd.). .

The content of impurities after purification is as shown in Table 1. Cationic impurities of 0.5 ppb or less and anionic impurities of 10 ppb or less were achieved, but organic impurities were 3 ppm or less as the total organic carbon content. I couldn't achieve it.

Comparative Example 3 Purification was carried out in the same manner as in Example 1 except that the solid phase production rate was 300 g / liter-raw material hydrogen peroxide solution / hr. The content of impurities after purification is as shown in Table 1. Cationic impurities of 0.5 ppb or less and anionic impurities of 10 ppb or less were achieved, but organic impurities could not reach 3 ppm or less as the total amount of organic carbon.

[0044]

[Table 1] Table 1 Impurities in aqueous hydrogen peroxide solution (unit: ppb) Al Fe Ni Cr Cr SO4 TOC (*) Raw material 79 6 0.6 1.5 8 8 20 Example 1 0.1 0.09 0.08 0.04 3 5 0.6 Example 2 0.4 0.2 0.09 0.08 5 5 0.6 Example 3 0.09 0.1 0.07 0.05 4 6 0.8 Comparative example 1 0.08 0.09 0.07 0.04 8 2 8 Comparative example 2 0.08 0.1 0.07 0.05 8 2 5 Comparative example 3 0.09 0.08 0.1 0.05 8 7 4 (*) Unit of TOC is ppm

[0045]

As described above, according to the method of the present invention, it is possible to remove the cationic and anionic metal impurities and the organic impurities in the hydrogen peroxide aqueous solution to a sufficiently low concentration, and to obtain a high purity. A hydrogen peroxide aqueous solution can be provided.

Claims (5)

[Claims] 1. An aqueous hydrogen peroxide solution containing 10 to 70% by weight of hydrogen peroxide is selected from the group consisting of a cation exchange resin layer, an anion exchange resin layer, and a cation exchange resin / anion exchange resin mixed layer. After contacting with at least two different layers, the hydrogen peroxide concentration is adjusted to a concentration of at least 45.2 wt.
A method for producing an aqueous hydrogen peroxide solution, which comprises cooling at a temperature of -56.1 ° C to precipitate a solid phase, and melting the obtained solid phase. 2. A cation exchange resin has SO ₃ H as an exchange group.
The method for producing an aqueous hydrogen peroxide solution according to claim 1, which is a cation exchange resin having a group. 3. The aqueous hydrogen peroxide solution according to claim 1, wherein the anion exchange resin is an anion exchange resin having a quaternary ammonium group as an exchange group, and the group is in the form of carbonate or bicarbonate. Manufacturing method. 4. The peroxide according to claim 1, wherein the aqueous hydrogen peroxide solution used for cooling to precipitate the solid phase is an aqueous hydrogen peroxide solution containing 45.2 to 61.2% by weight of hydrogen peroxide. Method for producing hydrogen solution. 5. The aqueous hydrogen peroxide solution according to claim 1, wherein the rate of solid phase formation when the aqueous hydrogen peroxide solution is cooled to precipitate the solid phase is 18 to 150 g / liter-raw material aqueous hydrogen peroxide solution · hr. Manufacturing method.