JP3250591B2 - Concentration and purification method of aqueous hydrogen peroxide solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is to provide a high-purity aqueous hydrogen peroxide solution by concentrating and purifying a crude aqueous hydrogen peroxide solution obtained by the anthraquinone method. The aqueous hydrogen peroxide solution obtained by the present invention may be used as a hydrogen peroxide aqueous solution for electronic industry where high purity is required, or as a raw material for further purifying and obtaining an ultra-high purity aqueous hydrogen peroxide solution in semiconductor production. Is widely used industrially as a wide range of reaction reagents.

[0002]

2. Description of the Related Art At present, an aqueous solution of hydrogen peroxide is industrially produced by autoxidation of anthraquinone. Hereinafter, this method is referred to as “anthraquinone method”. In the anthraquinone method, generally, a 2-alkylanthraquinone is hydrogenated in a water-insoluble solvent in the presence of a hydrogenation catalyst to form a corresponding anthrahydroquinone. In this method, hydrogen peroxide is obtained by regenerating the hydrogen peroxide and extracting it with water. Since the aqueous solution containing hydrogen peroxide contains a considerable amount of organic impurities consisting of anthraquinones, solvents and their degradation products, it is common to extract and purify the organic impurities with a water-insoluble solvent. The aqueous hydrogen peroxide solution thus obtained is hereinafter referred to as “crude hydrogen peroxide aqueous solution”.

[0003] A crude aqueous hydrogen peroxide solution contains 15 to
Although it contains 40% by weight, apart from the problem of impurities, it is the normal concentration of hydrogen peroxide used industrially.
Often it is further concentrated to 0-70% by weight. US Pat. No. 3,073,755, British Patent 1,326,282, Japanese Patent Publication No. Sho 3
7-8256 and Japanese Patent Publication No. 45-34926 have been proposed, but the flow shown in the flow diagram of FIG. 1 is generally used in principle. In FIG. 1, the crude aqueous hydrogen peroxide solution enters the evaporator 2 from the line 1 and passes through the line 3 to the gas-liquid separator 4. In the gas-liquid separator 4, volatile impurities,
It is separated into an aqueous solution of hydrogen peroxide which contains a vapor composed of hydrogen peroxide and water and a non-volatile impurity and is in equilibrium with the composition on the vapor side.

The vapor separated in 4 enters a rectification column 6 through a line 5. At 6, the rising steam reduces the concentration of hydrogen peroxide, the descending solution increases the concentration of hydrogen peroxide, and a concentrated aqueous hydrogen peroxide solution is withdrawn from the line 11 from the bottom of the tower. The vapor at the top is led to a condenser 8 through a line 7 and condensed water substantially free of hydrogen peroxide is discharged from a line 10. Supplied. The aqueous hydrogen peroxide solution separated by the gas-liquid separator 4 is circulated to the evaporator 2, but a part of the aqueous solution is extracted from the line 12 to prevent accumulation of impurities. These evaporation, gas-liquid separation, and rectification are usually performed under reduced pressure. Further, the aqueous solution of hydrogen peroxide separated by the gas-liquid separator 4 is extracted from the line 12 without being circulated to the evaporator 2, and is produced as a quality grade suitable for the use.

[0005] Aqueous hydrogen peroxide solution is widely used not only as a reaction reagent but also in many fields such as bleaching and chemical polishing, but in recent years, its use in the electronics industry such as semiconductors and printed wiring boards has increased. Accordingly, an extremely high-purity aqueous hydrogen peroxide solution is required, and a product obtained by rectifying and concentrating a crude hydrogen peroxide aqueous solution is also required to have high-purity quality with very few impurities. . However, these conventional techniques are not enough to reduce organic impurities and inorganic impurities to obtain an extremely high-purity aqueous hydrogen peroxide solution.

[0006] The crude hydrogen peroxide solution contains, as impurities, trace amounts of organic impurities having a small but not negligible concentration, and inorganic impurities resulting from elution from a reaction apparatus or piping. In some cases, it may contain a stabilizer added to suppress decomposition of hydrogen peroxide in the production process. Many of these are non-volatile, but if the gas-liquid separation in the vapor-liquid separator in the evaporation step is incomplete, inorganic impurities and non-volatile organic impurities contained in the crude hydrogen peroxide solution will be contained. The mist mixes into the rectification column and contaminates the concentrated aqueous hydrogen peroxide solution obtained from the bottom of the column. A demister is known as a gas-liquid separation method, but its use is limited due to the property that hydrogen peroxide is easily decomposed at the contact surface with the material, and its effect on gas-liquid separation is also limited. Also have limitations.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for effectively removing organic and inorganic impurities contained in a crude aqueous hydrogen peroxide solution and supplying a highly purified concentrated aqueous hydrogen peroxide solution. Is to provide.

[0008]

Means for Solving the Problems The present inventors have conducted intensive research to find a method for improving gas-liquid separation, and have found that organic impurities contained in a crude aqueous hydrogen peroxide solution can be obtained using the same type of gas-liquid separator. Surprisingly, it has been found that the gas-liquid separation performance is dramatically improved by the removal. That is, it has been found that when a crude aqueous hydrogen peroxide solution is brought into contact with a porous synthetic adsorption resin in advance, extremely good gas-liquid separation can be achieved, and the present invention has been completed.

That is, the present invention relates to a reduced pressure concentration method for separating a vapor and an accompanying liquid generated by evaporating an aqueous solution containing hydrogen peroxide by an evaporator with a gas-liquid separator, supplying the vapor to a rectification column and concentrating the vapor, After contacting the raw material hydrogen peroxide-containing aqueous solution with the porous synthetic adsorption resin in advance at a space velocity of ¹ to 50 hr ^-1 to reduce organic impurities to 50 ppm or less as organic carbon,
This is a concentration and purification method characterized by being supplied to an evaporator. A feature of the present invention resides in that a specific pretreatment is performed before evaporating the aqueous solution containing hydrogen peroxide with an evaporator.

In the present invention, the removal of organic substances in the crude hydrogen peroxide aqueous solution is carried out by bringing the crude hydrogen peroxide aqueous solution into contact with a porous synthetic adsorption resin. As the porous synthetic adsorption resin, a resin of a network polymer obtained by copolymerizing styrene and divinylbenzene and having no ion exchange group and / or a halogenated styrene-divinylbenzene copolymer resin is used. Good removal is possible by passing the solution through an adsorption column filled with one or more of the resins.

Specific resins include Amberlite XAD-1 and Amberlite XAD-Rohm and Haas.
2, Amberlite XAD-4, Amberlite XAD
-16, Sepabeads SP207 and Sepabeads SP825 manufactured by Mitsubishi Chemical Corporation. Flowing temperature is 0-40
° C is practical. Space Velocity
Is in the range of ^{1 to} 50 hr ^-1, preferably 5 to 30 hr ^-1 .

[0012] The crude hydrogen peroxide aqueous solution generally contains about 100 to 200 ppm of organic impurities as organic carbon (TOC), but the TOC is preferably 50 ppm or less, and more preferably, 50 ppm or less by contact with a porous synthetic adsorption resin. Reduce to 40 ppm or less.

The amount of evaporation in the evaporator is defined as 100 parts of hydrogen peroxide (pure content) entering the evaporator. It is preferable that 40 to 75 parts of (pure amount) be included. The pressure of the evaporator is 50 to 200 Torr, preferably 60 to
150 Torr. The temperature at the outlet of the evaporator, that is, at the inlet of the gas-liquid separator, is 40 to 90C, preferably 60 to 80C. The flow rate of the reflux water is controlled so that the concentration of the concentrated and purified aqueous hydrogen peroxide solution at the bottom of the rectification column becomes 40 to 70%.

The type of gas-liquid separation is not limited, but a cyclone or mist separator is preferred. The type of cyclone used in the present invention can be either a simple tangent inlet type or a full-circle spiral inlet type, but a standard cyclone with a simple tangential inlet as shown in FIG. 3 is preferably used. The standard cyclone is a Chemical Engineering Handbook or Perry's Chemical Enginee
rs'Handbook Sixth Ed. p.20-84 Any dimension ratio described in Fig.20-106 may be used. In FIG. 3, B = 1/5 * Dc to 1/4 * Dc, h = 1/2 * with respect to the cyclone diameter Dc.
Dc, l = 1/2 * Dc to 2/5 * Dc, H1 = Dc to 2 * Dc, H2 = 2 * Dc
Is preferred. The cyclone diameter Dc is 10 to 1 at the temperature and pressure under the above-mentioned evaporation condition when the air flow velocity at the cyclone inlet is equal to the above.
Good performance is obtained when designed to be 50 m / sec, preferably 20-100 m / sec. Aluminum, an aluminum alloy or stainless steel can be used as the material of the cyclone, but aluminum or an aluminum alloy is preferable in order to reduce decomposition of hydrogen peroxide due to contact.

The mist separator used in the present invention has a structure in which nets are stacked in multiple layers as shown in FIG. 4 and has a space ratio (a line constituting a net per unit volume of bulk of the multilayered nets). It is preferable that the volume of the linear body is 95 to 99% and the surface area (the surface area of the linear body constituting the net per unit volume of the bulk of the multi-layer net) is 150 to 1000 m ² / m ³ . In FIG. 4, the thickness H of the mist separator is shown.
3 preferably has a height of 100 to 1000 mm. The diameter Dm of the mist separator is such that the airflow velocity at the inlet of the mist separator is 1 to 50 m / se at the temperature and pressure under the above evaporation conditions.
c When preferably designed to be 5 to 25 m / sec,
Good performance is obtained. The material of the net of the mist separator is preferably a fluorocarbon resin or aluminum. Other metals are not preferable because they have a large area where gas and liquid come into contact with the vessel wall and the packing, and thus have a problem of contamination due to elution and the like and a problem of decomposition of hydrogen peroxide.

A plurality of cyclones and mist separators may be used, respectively, or a cyclone and a mist separator may be used in combination. The structure and operating conditions of the rectification column may be ordinary ones. The reflux water supplied to the top of the rectification column is such that hydrogen peroxide extracted from the bottom of the column is 40 to 70%.
The amount to be concentrated and purified to weight% is supplied.

The present invention will be described with reference to a flow diagram (FIG. 2). The crude hydrogen peroxide aqueous solution enters the adsorption resin tower 22 through the line 21 to remove organic impurities, and is supplied to the evaporator 24 through the line 23. The gas and liquid which came out of line 24 is line 2.
5 to the gas-liquid separator 26. At 26, the mixture is separated into a hydrogen peroxide aqueous solution containing a vapor composed of volatile impurities, hydrogen peroxide and water and a non-volatile impurity, and being in equilibrium with the composition on the vapor side. The aqueous hydrogen peroxide solution separated by the gas-liquid separator 26 is extracted from the line 41. The vapor separated at 26 is led to a rectification column 32 via a line 27.

The vapor containing hydrogen peroxide supplied to the rectification column 32 from the line 27 comes into contact with the reflux water supplied to the top of the column from the line 35 in countercurrent, and the liquid phase descending in the column and the liquid phase in the column A vapor-liquid equilibrium is formed during the rising gas phase. That is, the liquid phase descending from the top of the tower gradually descends while increasing the concentration of hydrogen peroxide, and the vapor containing hydrogen peroxide supplied from the bottom or bottom of the tower rises while decreasing the concentration of hydrogen peroxide. The steam may be fed to any part of the rectification column 32, but is preferably fed to the bottom or bottom of the column. By this rectification,
A purified high-purity aqueous hydrogen peroxide solution is extracted from a line 37.

From the top of the column, vapor containing substantially no hydrogen peroxide is led to a condenser 34 through a line 33 and condensed, and condensed water substantially free of hydrogen peroxide is supplied to a line 36.
Is discharged from As the reflux water supplied to the top of the rectification column, a part of the condensed water or purified water treated with an ion exchange resin or the like is supplied from a line 35. These evaporation, gas-liquid separation, and rectification are preferably performed under reduced pressure. The high-purity concentrated aqueous hydrogen peroxide solution extracted from the line 37 is stored in a tank, transported, and shipped.

The mechanism as to why the gas-liquid separation efficiency is greatly affected by the content of the organic impurities contained in the aqueous hydrogen peroxide solution is not clear, but the amount of the organic impurities attached to the surface of the gas-liquid separator depends on the content of the organic impurities. It is considered that the behavior of the liquid changes. That is, compared with the crude hydrogen peroxide aqueous solution, the hydrogen peroxide aqueous solution which has been brought into contact with the porous synthetic adsorption resin to reduce the organic impurities has a lower viscosity or foaming property, and is less likely to foam when vigorously stirred. It is presumed that the same phenomenon occurs on the surface of the gas-liquid separator, and in the aqueous hydrogen peroxide solution in which organic impurities have been reduced by contacting the porous synthetic adsorption resin, the liquid adhering to the surface of the gas-liquid separator is mist. It is thought that scattering is prevented.

[0021]

According to the present invention, organic impurities and inorganic impurities contained in a crude hydrogen peroxide aqueous solution are effectively removed,
A method for supplying a concentrated aqueous hydrogen peroxide solution purified to high purity is provided.

[0022]

Next, the present invention will be described more specifically with reference to examples. The invention is not limited to the figures or examples described.

Example 1 An adsorption resin tower (inner diameter: 600 mm, height: 1,000 mm) packed with 250 l of Sepabeads SP207 manufactured by Mitsubishi Kasei Co., Ltd. A Perry's Chemical Engineers' Ha having an inner diameter Dc of 1,240 mm was used as a gas-liquid separator.
ndbook Sixth Ed. p.20-84 Standard cyclone described in Fig.20-106 (see Fig.3, B = 310 mm, h = 620 mm, l = 620
mm, H1 = H2 = 2480 mm), a column having a diameter of 1,700 mm, and a rectification column having a rectifying column made of Al and filled with a porcelain filler at a height of 6,000 mm (schematically shown in FIG. 2). 38 ppm of evaporation residue to which 15 ppm of sodium pyrophosphate decahydrate and 20 ppm of aminotri (methylenephosphonic acid) were added as stabilizers
m, 90 ppm total organic carbon (TOC), 3,500 ppb sodium, 5,100
It was continuously supplied at a flow rate of l / hr. This flow rate is the superficial velocity
(SV) is equivalent to 20.4 hr ^-1 .

Evaporator outlet temperature 68 to 70 ° C, pressure 90 to 100 Torr
r, steady operation was performed with a reflux water amount of about 1,500 l / hr. The cyclone inlet gas velocity was calculated to be about 60m / s from the mass balance. Hydrogen peroxide concentration is 64 from line 41 below the cyclone
1,600 kg / hr of a withdrawn liquid of 1,600 kg / hr and a purified concentrated aqueous hydrogen peroxide solution with a hydrogen peroxide concentration of 54 wt% from the bottom of the rectification tower
/ hr. Metal impurities in the obtained concentrated aqueous hydrogen peroxide solution were analyzed by atomic absorption, and the evaporation residue was analyzed by JIS-K1463 method. Table 1 shows the results. The TOC of the liquid at the outlet of the adsorption resin tower was 28 ppm.

Example 2 As a cyclone, Perry's Chemical having an inner diameter Dc of 960 mm was used.
Engineers' HandbookSixth Ed.p.20-84 Fig.20-106
The same treatment as in Example 1 was performed using the same concentration equipment as in Example 1 except that the standard cyclone described was used.
The gas velocity at the cyclone inlet was calculated to be about 100m / s from the mass balance. Table 1 shows the analysis results of the concentrated aqueous hydrogen peroxide solution.

Comparative Example 1 Concentration and purification were carried out in the same manner as in Example 1 except that the adsorption resin tower was omitted and the crude hydrogen peroxide aqueous solution was directly supplied to the evaporator. Table 1 shows the analysis results of the concentrated aqueous hydrogen peroxide solution.

Comparative Example 2 Concentration and purification were carried out in the same manner as in Example 2 except that the adsorption resin tower was omitted and the crude aqueous hydrogen peroxide solution was directly supplied to the evaporator. Table 1 shows the analysis results of the concentrated aqueous hydrogen peroxide solution.

[0028]

[Table 1] Sodium concentration Evaporation residue Example 1 12 ppb 4 ppm Example 2 15 ppb 5 ppm Comparative example 1 75 ppb 11 ppm Comparative example 2 110 ppb 15 ppm

Example 3 An adsorption resin tower (inner diameter 600 mm, height 1,000 mm) packed with 250 liters of Amberlite XAD-2 manufactured by Organo Co., Ltd. was used, and instead of a cyclone, a fluororesin (Asahi Glass) was used as a gas-liquid separator. The product has a structure in which nets made by Aflon (trade name) are stacked in multiple layers, with a porosity of 98% and a surface area of 380 m ^2.
/ M ³ and a mist separator with an inner diameter of 1,500 mm filled to a height of 250 mm, using the same concentrating equipment as in Example 1 and performing the same treatment as in Example 1. Hydrogen peroxide concentration from line 41 of 64wt
1,600 kg / h of purified hydrogen peroxide solution with a hydrogen peroxide concentration of 54 wt% from the bottom of the rectification tower
got r. Evaporator outlet temperature 68-70 ° C, pressure 90-100 Torr,
Steady-state operation was performed with a reflux water amount of about 1,500 l / hr. The gas velocity at the inlet of the mist separator was calculated to be about 7m / s from the material balance. Table 2 shows the analysis results of the concentrated aqueous hydrogen peroxide solution.
The TOC of the liquid at the outlet of the adsorption resin tower was 35 ppm.

Comparative Example 3 A concentration and purification treatment was carried out in the same manner as in Example 3, except that the adsorption resin tower was omitted and the crude hydrogen peroxide aqueous solution was directly supplied to the evaporator. Table 2 shows the analysis results of the concentrated aqueous hydrogen peroxide solution.

COMPARATIVE EXAMPLE 4 A crude hydrogen peroxide aqueous solution was directly supplied to an evaporator by omitting the adsorption resin tower, and the thickness of the mist separator was increased to 500 mm by adding a net made of fluorocarbon resin. The same treatment as in Example 2 was performed using the same concentration equipment as in Example 3. Table 2 shows the analysis results of the concentrated aqueous hydrogen peroxide solution.

[0032]

[Table 2] Sodium concentration Evaporation residue Example 3 10 ppb or less 3 ppm Comparative example 3 95 ppb 14 ppm Comparative example 4 88 ppb 12 ppm

[0033]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a conventional apparatus for concentrating and purifying an aqueous hydrogen peroxide solution. 2: Evaporator 4: Gas-liquid separator 6: Rectification column 8: Condenser

FIG. 2 is a conceptual diagram of an apparatus for concentrating and purifying an aqueous hydrogen peroxide solution of the present invention.

FIG. 3 is a conceptual diagram of the structure of a cyclone Dc: cyclone diameter

FIG. 4 is a conceptual diagram of a mist separator Dm: mist separator diameter H3: mist separator thickness

──────────────────────────────────────────────────続 き Continued from the front page (56) References JP-A-63-156004 (JP, A) JP-B-45-34926 (JP, B1) JP-B-46-26095 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) C01B 15/013 B01J 20/26 B01D 15/00

Claims (3)

(57) [Claims] 1. A reduced-pressure enrichment method for evaporating an aqueous solution containing hydrogen peroxide by an evaporator, separating steam and accompanying liquid generated by an evaporator, supplying the steam to a rectification column, and concentrating the steam, comprising the steps of: A method for concentrating and purifying a solution comprising contacting an aqueous solution containing a porous synthetic adsorption resin in advance with a porous synthetic adsorption resin at a space velocity of ¹ to 50 hr ^-1 to reduce organic impurities to 50 ppm or less as organic carbon, and then supplying the same to an evaporator. 2. The method according to claim 1, wherein the porous synthetic adsorption resin is a network polymer resin obtained by copolymerizing styrene and divinylbenzene. 3. The method according to claim 1, wherein the porous synthetic adsorption resin is a halogenated styrene-divinylbenzene copolymer resin.