JPH0424282B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a high purity hydrogen peroxide stabilizer system containing 25 to 35% hydrogen peroxide. Hydrogen peroxide is thermodynamically unstable, but when pure it is not subject to spontaneous decomposition processes. However, hydrogen peroxide is subject to decomposition by heterogeneous or homogeneous catalysts. The stabilizer system selected for hydrogen peroxide will depend on the amount and nature of the decomposition catalyst with which the hydrogen peroxide is expected to be contacted. For example, very pure concentrated hydrogen peroxide, stored in large tanks by the manufacturer, requires very little stabilizer. However, dilute hydrogen peroxide or concentrated hydrogen peroxide, perhaps contaminated by the catalyst, requires high concentrations of stabilizer. Hydrogen peroxide for special purposes such as high purity hydrogen peroxide, semiconductor industry or chemical reagents must meet very strict specifications. In such applications, the hydrogen peroxide must be stable so as not to decompose when contaminated with common decomposition catalysts, but must also contain the minimum possible additives to suit the particular application. In general, certain hydrogen peroxides are H ₂ O ₂ 25 to
It is 35% by weight. Most hydrogen peroxide stabilization research has focused on the stabilization of hydrogen peroxide in concentrated solutions, storage or transportation in aluminum containers, or when high concentrations of hydrogen peroxide are present in other materials such as iron and copper as well as calcium, magnesium and aluminum. This has been done when diluted with either ordinary tap water or distilled water containing contaminants such as polyvalent cations. Examples of this technical composition are U.S. Pat.
No. 3383174, No. 3701825 and No. 4061721. These compositions contain typical commercially available hydrogen peroxide stabilized with organic compounds such as organic phosphonic acids, which are well known in the art as hydrogen peroxide stabilizers, and contain added tin compounds. It may or may not include. The combined effect of mixing two different stabilizer systems is rarely additive, with the result exceeding the sum of the effects of the individual stabilizer components, or the stabilizers cancel each other out, resulting in only a small stabilizing effect. There may be cases where there is no problem or there may be none at all. The decomposition and stabilization of hydrogen peroxide was reported in 1955 by Schumb et al.
Monograph Series” (American Chemical
Society Monograph Series) (Reinhold Publishing, New York) Hydrogen Peroxide477
−546 pages (1955) and recently Kirk in 1981−
Othmer's Encyclopedia of Chemical Technology
Technology), Volume 13, 3rd Edition (John Whalley & Sons, New York), pages 14-15 (1981), and both documents are included herein for reference. Tin compounds have long been known to be effective as stabilizers for hydrogen peroxide.
Schumb et al. have published their application in detail. 85
Optimum tin oxide (Sn ₂ O) for % hydrogen peroxide
The concentration was determined by Schumb et al. per 0.1 mg of ferric iron.
It is reported to be 0.83mg/. It is well known that the amount of stabilizer required decreases with increasing hydrogen peroxide concentration. Dilute hydrogen peroxide therefore requires higher amounts of tin than that reported by Schumb et al. for 85% hydrogen peroxide. It is well known that aluminum metal and aluminum ions do not catalytically decompose hydrogen peroxide. However, the presence of aluminum ions precipitates the tin stabilizer from the hydrogen peroxide. US Pat. No. 3,356,457 to Morris et al. states that up to 0.2 mg of aluminum can be present in a tin stabilized hydrogen peroxide composition. However, in the presence of a phosphate stabilizer, tin-stabilized peroxides can tolerate up to 1 mg/ml of aluminum ion. US Pat. No. 3,234,140 to Irani lists tris (methylene phosphonic acid) as a stabilizer for hydrogen peroxide solutions when the phosphonic acid is at a concentration of about 0.001 to about 5%. US Pat. No. 3,383,174 to Carnine et al. discloses a synergistic mixture of 50 to 300 mg of aminotris (methylene phosphonic acid), also known as nitrilotrimethylene phosphonic acid, and 10 to 150 mg of tin added as a sodium stannate. Kibbel et al. U.S. Patent No.
No. 3861022 contains 35% tin in the form of a soluble alkali metal salt such as sodium stannate and 1250 mg of aminotris (methylene phosphonic acid).
A hydrogen peroxide composition has been announced. US Pat. No. 3,701,825 to Radimer et al. describes ethylenediaminetetra (methylene phosphonic acid) as effective in stabilizing hydrogen peroxide. US Pat. No. 3,387,939 to Reilly et al. discloses that at least 20 mg/alkydenephosphonic acid is required to inhibit precipitation of tin stabilizers by aluminum or other polyvalent cations. The Reilly et al. patent also states that for optimal stability, it is preferred to adjust the pH of the hydrogen peroxide to an equivalence point by adding a suitable acid, such as nitric acid, sulfuric acid, lactic acid, citric acid, etc., if necessary. The use of high concentrations of stabilizers required by conventional methods for many applications such as chemical reagents and semiconductors is undesirable. The present invention is for very pure hydrogen peroxide solutions containing 2 to 35% by weight hydrogen peroxide with a maximum residue after evaporation of 20 mg/ml. For example, the reagent hydrogen peroxide ACS (American
Chemical Society) specifications are 29.0 to 32.0%
A maximum residue after evaporation of hydrogen peroxide of 20 mg/ml is required. It is well known that the tin compounds used in hydrogen peroxide stabilization are in the form of colloidal particles that are coagulated and neutralized by active ions such as calcium, magnesium and aluminum and common decomposition catalysts. Anions such as pyrophosphate, phosphate and sulfate are known to improve the stability of colloidal tin oxide. However, the critical minimum amounts of these substances in conventional methods are specified not to exceed 2 mg of phosphorus as phosphate and 5 mg of sulfate, so they cannot be used in the reagent hydrogen peroxide. It is essential for hydrogen peroxide for such applications to reduce the amount of stabilizer far below the critical minimum amount used in conventional methods. Additionally, it is common practice for many hydrogen peroxide users to strain the hydrogen peroxide through an 8 mm or finer strainer. This filtration reduces particulate matter in the solution and also reduces tin oxide, which is colloidal in the solution if not properly peptized. Tin oxide is necessary to prevent hydrogen peroxide from decomposing unless it is later contaminated with heavy metals. Therefore, the problem is that the necessary tin oxide is not removed by coagulation, precipitation or filtration, and at the same time the maximum residue after evaporation is 20
The goal is to keep it as an ultrafine particle that meets critical specifications such as mg/mg. According to the present invention, an aqueous hydrogen peroxide solution can be produced which has a maximum evaporation residue of 20 mg/ml and is stabilized from decomposition due to contamination. The aqueous solution is characterized by containing 25 to 35% by weight of hydrogen peroxide, 0.1 to 1.4 mg/Kg of tin, 0.1 to 2.5 mg/Kg of phosphate added as an organic phosphonic acid, and 0.1 to 5.5 mg/Kg of citric acid. Phosphonic acid and citric acid can be added either as free acids, alkali metal or ammonium salts, or as mixtures of free acids and salts, depending on the need to adjust the pH within the desired range. Usually tin is added as an alkali metal stannate, such as sodium stannate trihydrate or potassium stannate trihydrate. However, tin can be added in the form of a stannic oxide gel or in any other suitable form. Those skilled in the art will readily recognize that when tin is added as an alkali metal salt, large amounts of free phosphonic acid and hydroxycarboxylic acid are required to adjust the PH to the desired range. Any organic phosphonic acid can be used in the practice of this invention. The phosphonic acids are those containing nitrogen which can be oxidized to N-oxides such as aminotris-(methylenephosphonic acid) and ethylenediaminetetra-(methylenephosphonic acid) or alkydenphosphonic acids such as 1-hydroxyethyl-1,1
- It may also contain nitrogen that cannot be oxidized, such as diphosphonic acid. Acids are known to be useful as buffering agents and for adjusting the pH of hydrogen peroxide compositions within an optimal range. US Pat. No. 3,387,939 discloses that any suitable acid can be used for pH adjustment, such as nitric, sulfuric, lactic and citric acids. However, the prior art generally does not disclose that citric acid and/or salts are effective in tin-stabilized hydrogen peroxide compositions either as a stabilizer or as a peptizer to keep the colloidal tin sol in solution. I haven't even suggested it. It was unexpectedly discovered that citric acid is stabilized with tin and is effective in improving the stability of 25-35% hydrogen peroxide solutions with a maximum residue of 20 mg/ml after evaporation. Although the mechanism is not known, it is believed that it is related to the fact that the hydrogen peroxide aqueous solution of the present invention has a higher H ₂ O ₂ purity than the conventional excessively stabilized hydrogen peroxide aqueous solution. For example, "Journal of Chemical Society" by Davis et al.
(J.Chem.Soc.), (1953) pp. 1902-1906, “Kinetics of the Reaction of Hydrogen Peroxide and Hydrazine Contacted with Iodide in Acid” It is stated that the impurities were sufficient to contact the reaction between hydrogen peroxide and hydrazine. Addition of 0.002M (6.72 mg/) of ethylenediaminetetraacetic acid disodium salt (EDTA) was sufficient to eliminate the effect of the catalyst on the reaction. 25 to 35% with maximum residue after evaporation of 20mg/in the present invention
When hydrogen peroxide was used, it was found that EDTA had no effect on hydrogen peroxide stability or on the amount of tin retained after aging. Overall, from the previous literature,
It is clear from the publication by Davis et al. that catalytic reactions, especially in hydrogen peroxide solutions, cannot be compared unless they are of substantially the same purity. EXAMPLE COMPARATIVE EXAMPLE An experiment was conducted to examine the effects of variables such as tin concentration, phosphonic acid, inorganic pyrophosphate, and the presence or absence of aluminum. The measured responses are tin retention and hydrogen peroxide stability. Such factorial experimental designs are well known in the literature. For example, Jonson et al., from John Wille & Son, New York, published a book entitled "Statistics and Experimental Design."
Experimental Design), Volume 2, Chapter 15 (1977). Pure unstabilized hydrogen peroxide was adjusted to approximately 31% _by weight _H2O2 . Additive; Sodium Stanate 3
Tin as hydrate, phosphonic acid as nitrilotris (methylene phosphonic acid), pyrophosphate as sodium acid pyrophosphate and aluminum as aluminum nitrate were added. Tin was measured by plasma arc spectroscopy immediately after filtration using a 0.22 μm filter. The rate of change in tin concentration compared to the initial concentration was reported. Hydrogen peroxide was passed through a 0.22 μm filter, and after 24 hours at 100° C., the percentage of hydrogen peroxide retained in the liquid sample was measured. The tin measurement and stability were measured as described above for the sample immediately after production and the sample after storage for one day. Concentrations were reported as milligrams per kilogram of dilute hydrogen peroxide. (1mg/Kg=0.0001% by weight) The actual experimental conditions and results are summarized in the table.
The first response to high and low levels of individual variables.
It shows the order difference "response difference" and the sum of all responses "response total". This response difference that appears to be significant is indicated by an asterisk (*). "Response sum" is the sum (ΣYi) of all test data (16 tests in the table) for changes in tin concentration (i=1) or hydrogen peroxide stability (i=2). The average of these 16 measurements is =ΣYi/16. “Response difference” refers to high (+) and low (−) levels.
It is the algebraic difference of the response value Yi from the average value i at the level, and is equal to the following equation. Response difference = Σ[i-Yi(+)-Σ[i-Yi
(−)] The total response and the response difference are well-known statistical design values, and their details can be found in Statistics and
Experimental Design in Engineering and the
Physical Sciences; Vol.II, second edition
(Norman L. Johnson; co-signed by Fred. C. Leone; published by John Wiey & Sons, 1977) No.
It is described on pages 794-801. The initial tin concentration from the table is not an important variable.
Phosphonate and sodium acid pyrophosphate concentrations show a significant positive effect on tin response differences. Aluminum shows a significant negative effect. None of the variables had a significant effect on stability. This is expected since none of the samples contain cracking catalyst. Example 1 An experiment similar to the above comparative example was conducted. However, in this example, 1 mg/Kg of tin was added as an independent variable as either potassium stannate trihydrate or sodium stannate trihydrate, and the experiment was conducted using the following components: ethylenediaminetetraacetic acid (EDTA), nitrilotris ( methylene phosphonic acid), and citric acid in the presence or absence. Furthermore, 0.5 mg/Kg of aluminum was added as aluminum nitrate to each sample. The results are summarized in a table. Although it was expected that the presence of phosphonic acid was found to be significant, it was not expected that the efficacy of phosphonic acid would decrease after one day. This suggests that the phosphonic acid will be degraded. Furthermore, considering the above-mentioned literature by Davis et al., it was not expected that the presence or absence of EDTA would be insignificant. However, the hydrogen peroxide of Davis et al. had an evaporation residue of 670 mg or more and was not a high-purity hydrogen peroxide with an evaporation residue of 20 mg or less. It was further unexpected to find that not only was the response difference for citric acid more significant than that for phosphonic acid, but also that the response difference did not decrease significantly over time. This recognition was known to be effective for hydrogen peroxide solutions with large amounts of evaporation residue.
This is difficult to understand considering the non-significant difference in response to EDTA. The effect of citric acid is particularly surprising in that the prior art considers citric acid suitable for use as an acidifying agent in low purity industrial aqueous peroxide solutions. Its use other than maintaining tin as a sol in hydrogen peroxide solutions or as an acidifying agent in stabilized hydrogen peroxide compositions has remained undiscovered to date.

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Claims (1)

[Claims] 1 Maximum residue on evaporation of 20 mg, characterized in that it contains 0.1 to 1.4 mg/Kg of tin, 0.1 to 2.5 mg/Kg of phosphate added as organic phosphonic acid and 0.1 to 5.5 mg/Kg of citric acid. A 25-35% aqueous solution of hydrogen peroxide stabilized against decomposition in the presence of polyvalent cations as indicated by /. 2. The aqueous solution according to claim 1, wherein the organic phosphonic acid is aminotris (methylenephosphonic acid). 3 Organic phosphonic acid is ethylenediaminetetra-
The aqueous solution according to claim 1, which is (methylenephosphonic acid). 4 Organic phosphonic acid is 1-hydroxy-1,1-
The aqueous solution according to claim 1, which is diphosphonic acid.