KR900003647B1 - Process for preparing aqueous chloroxide aolution - Google Patents

Abstract

A process for prepg. an aq. chloroxide-soln. comprises (a) adding 30% NaClO2 soln. 35-105 wt.% and 15-17% NaCoO soln. 10-30 wt.% to water 15-45 wt.%, (b) adding mineral acid i.e. 10% H2SO4 3-9 wt.% slowly to control pH 3-4, and (c) adding 98-100% Na2CO3 soln. 1-2 wt.% to adjust pH 6.5-7.5. The aq. chloroxide-soln. is stable for few months, and esp. is useful for purifying drinkwater.

Description

Method for preparing an aqueous chlorooxide solution

The present invention relates to a process for the preparation of an aqueous chlorooxide-solution. U.S. Patent No. 3,585,147 describes a method for preparing an aqueous chlorooxide solution, which is simultaneously recognized by dissolving an alkali metal zinc sulphate and an alkali or alkaline-chloride in water and adjusting the pH value to 7 to 13. .

When the pH value is adjusted to 6 or less, chloro dioxide is liberated, where a large amount of chloro dioxide can be liberated if chloride is present. In known processes only a small amount of chlorodioxide is liberated in the absence of chloride. A disadvantage here, however, is that the alkaline sodium chlorite-solutions obtained by the above known methods undergo a reverse reaction with sodium chlorite relatively quickly, for example, long term storage is impossible for several months.

It is an object of the present invention to provide an aqueous chlorooxide-solution in which stable and long term storage is possible and in which a large amount of chlorooxide is dissolved. This object was achieved by the following method. That is, 35 to 105 parts by weight of chlorite and 10 to 30 parts by weight of hypochlorite are added to 15 to 45 parts by weight of water, and 3 to 9 parts by weight of inorganic acid is gradually added to the aqueous solution obtained to obtain a pH value. After acidification to 3-4, the pH value is then adjusted to 6.5-7.5 by addition of 1-2 parts by weight sodium carbonate.

The process according to the invention is carried out in the absence of chloride, in which a large amount of chlorooxide is produced and contained in solution, as in US Pat. No. 3,585,147. Water containing chlorooxide-solutions does not affect odor and taste, and furthermore the production of chloroamine is also inhibited. It is therefore particularly advantageous when the chlorooxide-solutions prepared by the process according to the invention are used in drinking water and bath water. It does not affect the natural smell and taste of the drink at all, and in the case of bathing water, there is no risk of itching or eye disease caused by the production of chloroamine. An advantage above all is that there is no need for stabilizers such as peroxides, since the aqueous chlorooxide-solution is stabilized only with sodium carbonate. Since the chlorooxide-solution prepared according to the present invention can be recognized even after several months, the range of use of this material can be broadly widened, and the recognition at the time of use is also excellent. Last but not least, it can be used for beverage tablets. The aqueous chlorooxide-solutions prepared according to the invention can also be advantageously used in water, cooling water and waste water which are commonly used as oxidant- and disinfectants.

Further advantageous modification methods and the like according to the object of the method according to the invention are described in the claims. The following examples are presented to illustrate the method of the present invention.

EXAMPLE

To 30 parts by weight of water, 70 parts by weight of 30% of sodium chlorite-solution and 20 parts by weight of 16% of sodium hypochlorite-solution are added, and 6 parts by weight of 10% of sulfuric acid solution to the aqueous solution obtained The pH value is adjusted to about 4 by addition. This acidic aqueous solution forms chloro oxide when a certain reaction time has elapsed. The pH value is adjusted to about 7.0 by adding 1.5 parts by weight of 98% to 100% sodium carbonate as a stabilizer.

The aqueous solution obtained by this method contains 20 to 25% chlorooxide and the pH value is about 7.0.

Claims (3)

In a method of preparing an aqueous chlorooxide solution by dissolving chlorite and carbonate in water and adjusting it to a pH value of neutral or weak alkali, firstly, in an amount of 35 to 105 parts by weight of chlorite in 15 to 45 parts by weight of water; 10 to 30 parts by weight of hypochlorite was dissolved, and 3 to 9 parts by weight of inorganic acid was gradually added to the aqueous solution obtained thereby acidifying the pH value to 3 to 4, followed by addition of 1 to 2 parts by weight of sodium carbonate. Process for the preparation of an aqueous chlorooxide-solution, characterized in that the pH value is adjusted to 6.5 to 7.5. 2. A process according to claim 1, wherein 30% sodium chlorite-solution, 15% to 17% sodium hypochlorite solution and 98% to 100% sodium carbonate are used. The process for producing an aqueous chlorooxide-solution according to claim 1 or 2, wherein 10% sulfuric acid is used.