KR101286088B1 - Method for Preparing Hypochlorous Acid Water with High Stability - Google Patents

Abstract

The present invention discloses a method for preparing hypochlorous acid, including adjusting the pH of sodium hypochlorite solution to be 2.5 to 6.0 using phosphoric acid. The method can produce hypochlorous acid water that is stable at low temperatures.

Description

Method for Preparing Hypochlorous Acid Water with High Stability

The present invention relates to a method for producing hypochlorous acid water having high stability.

In modern society, most people rely on meals for more than one meal a day, and hygiene management is inevitably a problem where few suppliers have to prepare large quantities of food for many. Collective food poisoning, which often occurs in large meal facilities, is an example of the importance of thorough hygiene control. For this reason, the KFDA is currently making and enacting food standards notifications on hygiene management of large feeding facilities and schools, which are obliged to effectively and safely sterilize and disinfect them. On the other hand, the demand for sterilization and disinfection is very high, as it is necessary to sterilize and disinfect not only food ingredients but also tools and facilities that are at risk of bacterial propagation and airborne infection.

Korean Patent Registration No. 10-0706215 (2007.04.04. Registration)

The present invention is to provide a method for easily preparing a hypochlorous acid water excellent in sterilization and disinfection, excellent in room temperature and low temperature stability. In addition, it is prepared by the method for preparing hypochlorous acid to provide excellent hypochlorite water having excellent sterilizing and disinfecting power and stability at low temperature as well as at room temperature.

One aspect of the present invention provides a method for producing hypochlorous acid water (hypochlorous acid water) comprising the step of adjusting the pH of the sodium hypochlorite solution to 2.5 to 6 using phosphoric acid.

Another aspect of the invention provides a stable hypochlorous acid water prepared by the above method and after freezing.

Hypochlorite water obtained by the manufacturing method according to an aspect of the present invention has excellent disinfection and sterilizing ability because it maintains an effective chlorine concentration, but the pH is constantly maintained in a weak acidity because the ratio of hypochlorous acid to hypochlorous acid is high. In addition, it maintains stability at low temperature as well as at room temperature and can be conveniently used throughout the four seasons. Hypochlorite water production method according to an aspect of the present invention is easy and low cost without the existing expensive hypochlorous acid production machine, excellent disinfection and sterilization power, it is possible to produce a stable hypochlorite water for long-term storage. In addition, since the desired pH and effective chlorine concentration can be easily adjusted in the manufacturing process, it is possible to prepare not only low concentrations of 100 ppm or less, but also high and stable hypochlorous acid water. Hypochlorite water according to the present invention can be used in all fields that require environmentally friendly sterilization and disinfection, in particular can be usefully used for food hygiene management, hygiene management of appliances, home hygiene management, crop pest prevention, medical care, etc. .

1 is a graph showing the ratio of chlorine gas, hypochlorous acid (HOCl), and sodium hypochlorite (NaOCl) according to pH.
Figure 2 is a graph showing the residual rate (%) after 50 ℃, 14 days according to the initial pH of 500 ppm hypochlorous acid water.
Figure 3 is a graph showing the residual rate (%) after 50 ℃, 14 days according to the initial pH of 2000 ppm hypochlorous acid water.
Figure 4 is a graph showing the residual ratio (%) after 50 days, 14 days according to the initial pH of 5000 ppm hypochlorous acid water.

The representative is chlorine as inorganic disinfectant, chlorine is used to disinfect a chlorine gas, hypochlorous acid (hypochlorous acid, HOCl), and hypochlorite ion (OCl ^-) are present in three forms of the sodium hypochlorite is present in an (NaOCl) . In general, when the pH of water in which HOCl is present is low (usually below pH 2), it is mostly in the form of chlorine gas; when the pH of water is high (usually above pH 9), it is in OCl ^- form and the pH is 3 to 7 days. It is mainly present in HOCl form. That is, the three forms are all components starting from one substance, and the three components coexist with each other by varying their ratios according to pH (see FIG. 1).

In the case of chlorine gas, it is very soluble in water, so if it is not sealed, it leaves the solution and generates toxic chlorine gas. It is toxic and smells and colors. The bactericidal effect is also lower than hypochlorous acid.

Sodium hypochlorite is also known to have 50 times lower bactericidal activity than hypochlorous acid when it has the same effective chlorine concentration, and mold resistance and bleaching power are also lower than hypochlorous acid. It is also known to cause more fiber damage and severe bulge than hypochlorous acid. And there is a disadvantage that it is difficult to remove the heavy slip remaining after using it.

As such, hypochlorous water has the highest disinfection and sterilization power among the three forms, and in the past, hypochlorite water could be produced only by using expensive machines. In addition, expensive machines are limited in their ability to produce low concentrations of hypochlorite water of less than 100 ppm for economic and practical reasons.

Accordingly, the present inventors have developed a method that can easily and efficiently produce a stable hypochlorous acid water with excellent disinfection and sterilization power after repeated studies.

Hereinafter, the present invention will be described in detail.

One aspect of the present invention provides a method for producing hypochlorous acid water by adjusting the pH of the sodium hypochlorite liquid to 2.5 to 6 using an acid. Through this method, hypochlorous acid water can be easily produced at low cost without using an expensive machine. Furthermore, the hypochlorous acid water which has an effective chlorine corresponding to the effective chlorine concentration of the sodium hypochlorite liquid used for hypochlorite water manufacture can be manufactured. That is, hypochlorite water having a low to high concentration of effective chlorine concentration can be produced according to the effective chlorine concentration of the sodium hypochlorite liquid used for the production of hypochlorous water. In addition, the hypochlorous acid water has a high initial concentration residual ratio, its effectiveness is high.

One aspect of the present invention provides a method for producing hypochlorous acid water by adjusting the pH of the sodium hypochlorite solution to 2.5 to 6 using phosphoric acid. It is generally known that freezing hypochlorous acid reduces its stability. Hypochlorous acid water prepared using only hydrochloric acid or sulfuric acid has the disadvantage of lower temperature stability, in particular, lower stability after freezing, compared to hypochlorous acid water prepared using a machine. Because of this, the stability of hypochlorous acid water during winter may be difficult to use. On the other hand, hypochlorous acid water prepared using phosphoric acid can be conveniently used in winter because it can maintain good stability even at low temperatures. Another aspect of the present invention provides a method of stabilizing the prepared hypochlorous acid water at low temperature by adjusting the pH of the sodium hypochlorite solution to 2.5 to 6 using phosphoric acid.

In one aspect of the invention "low temperature" may mean below room temperature, specifically freezing temperature, for example -50 ℃ to 1 ℃, specifically -40 ℃ to 1 ℃, more specifically -30 ℃ to May mean 1 ° C.

Another aspect of the present invention provides a method for producing hypochlorous acid water by adjusting the pH of the sodium hypochlorite solution to 2.5 to 6 using phosphoric acid and sulfuric acid. Even when phosphoric acid and sulfuric acid are used together, hypochlorous acid water stable at low temperature can be produced. In another aspect of the invention, the volume ratio of phosphoric acid and sulfuric acid may be 20: 1 to 1:20, specifically 10: 1 to 1:10, more specifically 5: 1 to 1: 1. When used in the volume ratio, not only is the present invention suitable for exhibiting the intended effect, but also satisfactory both the stability and safety of hypochlorous acid water, it may be appropriate to be used in the volume ratio in terms of cost-effectiveness.

In one aspect of the present invention, when using phosphoric acid and sulfuric acid, the pH of the sodium hypochlorite liquid can be adjusted with a mixed acid of phosphoric acid and sulfuric acid. In another aspect of the present invention, when using phosphoric acid and sulfuric acid, the pH of the sodium hypochlorite solution is first adjusted to 4 to 9 with one of phosphoric acid and sulfuric acid, and then sodium hypochlorite solution using the other acid. PH can be adjusted from 2.5 to 6.

In one aspect of the present invention, by using an acid to adjust the pH of the sodium hypochlorite liquid is 3 to 5, specifically 3 to 4.5, more specifically 3 to 4 can be prepared hypochlorous acid water. When the pH is in the above range, hypochlorous acid water may be prepared in which the pH is stably maintained for a long time.

In one aspect of the invention, the pH of sodium hypochlorite liquid having an effective chlorine concentration of high concentration, for example 100 ppm to 100,000 ppm, specifically 300 ppm to 50,000 ppm, more specifically 700 ppm to 10,000 ppm, using acid. It can be adjusted to produce a stable hypochlorous acid water having the same effective chlorine concentration. The high concentration of hypochlorous acid prepared as described above is efficient because it can have a high disinfection and sterilization power even in a small amount compared to the low concentration of hypochlorous acid, it is economical in that it can be further diluted according to the use.

In one aspect of the invention, the 100 ppm to 100,000 ppm sodium hypochlorite solution may be prepared by diluting 100,000 ppm to 140,000 ppm, specifically 120,000 ppm to 130,000 ppm sodium hypochlorite solution with water. In another aspect of the present invention, the water for diluting the sodium hypochlorite liquid is not particularly limited, but in order to minimize the impurities that may come out when the water is added, pure water or soft water (soft water) to increase the stability of the hypochlorite water. water) can be used.

In one aspect of the invention, the sodium hypochlorite liquid used for the preparation of hypochlorous water may be prepared by a synthetic method after electrolysis. Specifically, sodium chloride may be prepared by electrolyzing in a conventional manner to form caustic soda and chlorine, and then reacting them to synthesize hypochlorite ions. In another aspect of the present invention, the electrolysis is not limited to a specific electrolysis method, but may be formed by a diaphragm type electrolysis method.

In one aspect of the present invention, the concentration of hypochlorite ions or the effective chlorine concentration may be determined by the method described in the food additive revolution.

One aspect of the present invention provides a hypochlorous acid water prepared by the method. The hypochlorous acid water is stable at low temperature as well as at room temperature, and thus can be conveniently used throughout the four seasons. In another aspect of the invention, the hypochlorous acid water is stable after freezing, for example, the effective chlorine residual ratio may be 30% or more, specifically 50% or more, more specifically 70% or more. In another aspect of the invention, the hypochlorous acid water can be used for disinfection, sterilization, washing or bleaching. In another aspect of the present invention, the hypochlorous acid water may be used as an oxidizing agent. The hypochlorous acid water is stable for a long time, so that it can be distributed and stored for a long time. In addition, when manufactured with high concentration of hypochlorous acid over 100 ppm, it can show high disinfection and sterilization effect even in small amount, and it can be used for a long time because high concentration of hypochlorous acid can be diluted with water depending on the purpose. to be.

Hereinafter, the configuration and effects of the present invention will be described in more detail with reference to the preparation and experimental examples. However, the following Preparation Examples and Experimental Examples are provided only for the purpose of illustration in order to help the understanding of the present invention, but the scope and scope of the present invention is not limited thereto.

Preparation Example 1 Preparation of Sodium Hypochlorite Liquid-Dilution

Pure water is added to 12-13% sodium hypochlorite solution so that the effective chlorine concentration is 500 ppm, 2000 ppm and 5000 ppm, respectively. At this time, the pH of sodium hypochlorite liquid is 10 to 12.

Production Example 2 Preparation of Sodium Hypochlorite Liquid-Electrolysis

Sodium chloride is electrolyzed using a conventional electrolysis method, and sodium hypochlorite solution is prepared by synthesizing caustic soda and chlorine gas to have an effective chlorine concentration of 500 ppm, 2000 ppm and 5000 ppm, respectively.

Experimental Example 1 Evaluation of Stability of Hypochlorite Water

The sodium hypochlorite solution, which has an effective chlorine concentration of 500 ppm, 2,000 ppm and 5,000 ppm, respectively, is titrated with phosphoric acid to pH 3.0 to 7.0, respectively. After the titration, the initial effective chlorine concentration (ppm) and storage at 50 ° C. for 14 days, the effective chlorine concentration (ppm) was measured by a conventional method in the art to calculate the residual rate (%). In addition, after storing for 14 days at 50 ℃ was measured and recorded the pH. Specific initial pH and measurement results are shown in Tables 1 to 3 and FIGS. 2 to 4 below. 2 to 4 are graphs showing the residual percentages (%) after 50 ° C. and 14 days according to the initial pH of the sodium hypochlorite solution, which is 500 ppm, 2,000 ppm, and 5,000 ppm, respectively.

In general, it is believed that the stability results after 14 days at 50 ° C. and 1 year at room temperature are similar. That is, as a result of the stability after storage for 14 days at 50 ℃ can be expected a stability result after storage for 1 year at room temperature.

500 ppm Initial effective chlorine concentration (ppm) Effective Chlorine Concentration (ppm) after 50 ° C, 14 days Survival rate pH pH 3.0 505 299 59.2% 3.39 pH 3.2 513 323 63.0% 3.57 pH 3.4 519 327 63.0% 3.68 pH 3.6 521 336 64.5% 3.67 pH 3.8 522 359 68.8% 3.93 pH 4.0 523 383 73.2% 3.75 pH 4.5 525 375 71.4% 3.91 pH 5.0 525 337 64.2% 3.78 pH 6.0 529 305 57.7% 4.14 pH 7.0 529 183 34.6% 6

2000 ppm Initial effective chlorine concentration (ppm) Effective Chlorine Concentration (ppm) after 50 ° C, 14 days Survival rate pH pH 3.0 1882 1022 54.3% 3.84 pH 3.2 1978 1051 53.1% 3.97 pH 3.4 2020 1165 57.7% 4.04 pH 3.6 2043 1237 60.5% 3.93 pH 3.8 2054 1258 61.2% 4 pH 4.0 2060 1245 60.4% 4.03 pH 4.5 2065 1166 56.5% 4.04 pH 5.0 2065 1129 54.7% 3.99 pH 6.0 2069 971 46.9% 4.11 pH 7.0 2070 497 24.0% 4.32

5000 ppm Initial effective chlorine concentration (ppm) Effective Chlorine Concentration (ppm) after 50 ° C, 14 days Survival rate pH pH 3.0 4265 1773 41.6% 3.63 pH 3.2 4673 1750 37.4% 3.8 pH 3.4 4853 1556 32.1% 4 pH 3.6 4931 1570 31.8% 3.96 pH 3.8 4987 1540 30.9% 4.13 pH 4.0 5038 1558 30.9% 4.06 pH 4.5 5059 1536 30.4% 4.01 pH 5.0 5084 1397 27.5% 4.13 pH 6.0 5046 1324 26.2% 4.19 pH 7.0 4991 776 15.5% 4.48

As can be seen from the above results, when the hypochlorite water is prepared by using an acid so that the pH of the sodium hypochlorite solution is 3 to 6, the hypochlorous acid water is kept stable for a long time in the range of pH 3 to 4.5, the concentration It also stays above a certain level. In other words, if sodium hypochlorite falls within a certain range of pH using acid, a high concentration of hypochlorous acid stable at room temperature can be obtained for at least one year.

Experimental Example 2 Low Temperature Stability Evaluation

(1) Low Temperature Stability Evaluation of Low Concentration Hypochlorite Water

Prepared in substantially the same manner as in Experimental Example 1, the sodium hypochlorite solution using sulfuric acid, phosphoric acid and hydrochloric acid so that the pH of about 5 to 6 prepared by about 50 to 60 ppm of water and conventional electricity after the hypochlorite water (Medi flux ^® produced after decomposition synthesis method one days frozen measure the effective chlorine concentration and pH. after the same number of hypochlorite based one days at room temperature to measure the effective chlorine concentration and pH. the The results are shown in the table below.

frozen Room temperature Kind of the mountain Effective Chlorine Concentration (ppm) pH Effective Chlorine Concentration (ppm) pH Sulfuric acid Early 60 6.1 60 6.1 After 1 day 40 3.8 59 6.2 stability 66.7% 98.3% Phosphoric Acid Early 61 5.8 61 5.8 After 1 day 54 5.9 59 6 stability 88.5% 96.7% Hydrochloric acid Early 61 5.8 61 5.8 After 1 day 38 3.9 59 6.1 stability 62.3% 96.7% Medilaks ^® Early 55 5.8 55 5.8 After 1 day 46 4.5 53 5.5 stability 83.6% 96.4%

As can be seen from the above results, the stability of hypochlorous acid water at room temperature was similar in all cases, but the stability after freezing for one day was the best hypochlorous acid water made of phosphoric acid. That is, when using phosphoric acid it can be seen that stable hypochlorous acid water can be produced even at low temperatures.

(2) Low Temperature Stability Evaluation of Concentrated Hypochlorite Water

Prepared in substantially the same manner as in Experimental Example 1, 500 ppm and 2000 ppm hypochlorous acid water prepared by using a sulfuric acid and phosphoric acid so that the pH of the sodium hypochlorite solution is about 3 to 4 per day, 1 week After freezing for 2 weeks, the effective chlorine concentration and pH were measured. The results are shown in the table below.

Early 1 day 1 week 2 weeks Sulfuric acid
500 ppm Effective Chlorine Concentration (ppm) 543 344 289 268 pH 3.9 2.7 - 2.5 stability 63.4% 53.2% 49.4% Phosphoric Acid
500 ppm Effective Chlorine Concentration (ppm) 543 502 458 439 pH 3.9 3.8 - 3.9 stability 92.4% 84.3% 80.8% Sulfuric acid
2000 ppm Effective Chlorine Concentration (ppm) 1973 1039 811 725 pH 3.6 2.5 - 2.4 stability 52.7% 41.1% 36.7% Phosphoric Acid
2000 ppm Effective Chlorine Concentration (ppm) 2000 1912 1580 1548 pH 3.6 3.8 - 4 stability 95.6% 79.0% 77.4%

As can be seen from the above results, when preparing a high concentration of hypochlorous acid water using phosphoric acid, the stability after freezing was higher than when using sulfuric acid. In other words, it can be seen that when using phosphoric acid, a stable high concentration of hypochlorous acid can be prepared even at low temperatures.

(3) Low Temperature Stability Evaluation of Hypochlorite Water Prepared by Mixing Acid

Prepared in substantially the same manner as Experimental Example 1, by using a mixture of phosphoric acid and sulfuric acid so that the pH of the sodium hypochlorite solution is about 3 to 4 frozen in 2000 ppm hypochlorous acid water prepared for 1 day and then effective chlorine Concentration and pH were measured. The same hypochlorous acid water was placed at room temperature for 1 day, and the effective chlorine concentration and pH were measured. The results are shown in the table below.

frozen  Room temperature content pH content 10% phosphoric acid (v / v) + 90% sulfuric acid (v / v) Early 2037 3.6 2037 After 1 day 1078 2.5 2004 stability 52.9% 98.4% 40% phosphoric acid (v / v) + 60% sulfuric acid (v / v) Early 2024 3.6 2024 After 1 day 1100 2.6 1975 stability 54.3% 97.6% 60% phosphoric acid (v / v) + 40% sulfuric acid (v / v) Early 2032 3.6 2032 After 1 day 1170 3.1 1996 stability 57.6% 98.2% 87% phosphoric acid (v / v) + 13% sulfuric acid (v / v) Early 2035 3.6 2035 After 1 day 1370 3.7 1998 stability 67.3% 98.2% 90% phosphoric acid (v / v) + 10% sulfuric acid (v / v)
Early 1997 3.3 1997 After 1 day 1466 3.4 1941 stability 73.4% 97.2% 94% phosphoric acid (v / v) + 6% sulfuric acid (v / v)
Early 2019 3.6 2019 After 1 day 1523 3.5 1964 stability 75.4% 97.3%

As can be seen from the above results, when preparing hypochlorous acid water by using a mixture of phosphoric acid and sulfuric acid, the higher the ratio of phosphoric acid, the higher the stability after freezing. In other words, when using a mixture of phosphoric acid and sulfuric acid it can be seen that the higher the ratio of phosphoric acid can produce a high concentration hypochlorous acid stable at low temperatures.

Hypochlorite water has better sterilizing power and bleaching power than sodium hypochlorite at the same effective chlorine concentration. However, the manufacturing method of hypochlorous acid water using the expensive machine known to date is high manufacturing cost and such a method could not be widely used because the production of high concentration hypochlorous acid is economically and practically impossible. The present invention provides a method for producing stable hypochlorous acid water at room temperature and low temperature by adjusting the pH of sodium hypochlorite liquid using acid, especially phosphoric acid. Through the above method, hypochlorous acid water excellent in four seasons storage stability and sterilization power can be easily produced at low cost.

Claims (9)

Titrating the sodium hypochlorite solution with an aqueous solution of phosphoric acid to adjust the pH of the sodium hypochlorite solution containing phosphoric acid to 3 to 5;
A method for producing hypochlorous acid water in which the effective chlorine concentration of sodium hypochlorite liquid remains at 70% or more of the initial concentration at -50 to 1 ° C.
delete delete delete The method of claim 1,
Sodium hypochlorite liquid has an effective chlorine concentration of 100 ppm to 100,000 ppm.
The method of claim 5, wherein
Sodium hypochlorite solution is a method of producing hypochlorous acid water, characterized in that diluted from 100,000 ppm to 140,000 ppm sodium hypochlorite solution with water.
The method of claim 1,
Sodium hypochlorite solution is a method of producing hypochlorous acid water, characterized in that prepared by the synthesis method after electrolysis.
Hypochlorite water prepared by the method according to any one of claims 1 and 5.
The method of claim 8,
Hypochlorite water for disinfection, sterilization, cleaning or bleaching.

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