KR810000906B1 - Method of producing sodium percarbonate - Google Patents

Abstract

Stabilizing sodium percarbonate was prepd. by reaction of sodium carbonate, hydrogen peroxide and mixture, addition of salicilic acid, sodium salicilate, stabilizing agent such as magnesium silicate, magnesium sulfate, sodium metasilicate or water glass.

Description

Process for preparing stable sodium percarbonate

The present invention relates to a method for producing stable sodium percarbonate by adding salicylic acid or sodium salicylate as a stabilizer in preparing sodium percarbonate.

Sodium percarbonate is known as a bleach or oxidizing agent, and is generally produced by applying hydrogen peroxide to sodium carbonate, and is typically a white powdery substance represented by NaNa ₂ CO ₃ · 1.5H ₂ O ₂ .

Sodium percarbonate has the advantage of high solubility in water and easily dissolves in cold water compared to sodium perborate with a similar action.

However, sodium percarbonate has a drawback that the storage stability is so bad that it loses free radicals faster than sodium perborate during storage.

This tendency is further accelerated by heat. In addition, since sodium percarbonate has a strong affinity for water, the surface becomes moisture-absorbed even by a small amount of moisture, so that decomposition is accelerated.

An object of the present invention is to provide a stable sodium percarbonate that withstands long term storage by improving the storage stability of sodium percarbonate.

As a result of intensive studies, the inventors have found that the addition of salicylic acid or sodium salicylate as a stabilizer in the production of sodium percarbonate significantly improves the stability of sodium percarbonate. Salicylic acid or sodium salicylate is a type of phenolic aromatic acid or salt of white matter represented by 2-HOC ₆ H ₅ COOH or 2-HOC ₆ H ₅ COONA, especially since the salt is very well soluble in water, It can be used as an aqueous solution. Since salicylic acid or sodium salicylate forms chelates with heavy metals, which are decomposition catalysts of hydrogen peroxide, it is believed that stabilization is achieved by inhibiting the decomposition of sodium percarbonate.

In the process of the present invention, in preparing sodium percarbonate, salicylic acid or sodium salicylate powder is combined with a known stabilizer (described below) in combination with sodium carbonate powder, or an aqueous sodium salicylate solution is added to hydrogen peroxide, and then the solution is applied to sodium carbonate and wetted. The reaction product is dried by heating air.

At this time, the amount of salicylic acid or sodium salicylate should be 0.1-5.0% with respect to sodium percarbonate.

As a known stabilizer, one or more of magnesium compounds, such as magnesium silicate, magnesium sulfate, and magnesium oxide, and silicates such as sodium metasilicate and water glass are preferably used.

According to the present invention, the stability of sodium percarbonate, which cannot be obtained by using only the above known stabilizer, can be remarkably improved by the combined use of salicylic acid or sodium salicylate.

In particular, the water-soluble sodium salicylate salt is dissolved in water and hydrogen peroxide, so it can be directly added and dissolved in hydrogen peroxide. Therefore, the sodium salicylate salt is uniformly sprayed with hydrogen peroxide when reacting by spraying hydrogen peroxide on sodium carbonate powder by the dry method. It has the advantage of giving one stability.

EXAMPLE

A non-kerer reactor made of polyethylene material contains 119 g of sodium carbonate powder (sodium carbonate content 89.0%), and the sodium salicylate powder is premixed in an amount of 1% to sodium percarbonate. Subsequently, 102 g of 50% hydrogen peroxide was added in half, and 1 g of magnesium sulfate and sodium silicate, each of which are known stabilizers, were added to the mixture, and the mixture was added dropwise to sodium carbonate over about 30 minutes, followed by stirring.

The wet product is dried for about 60 minutes by heating air at 50 DEG C to obtain sodium percarbonate.

After stabilizing sodium percarbonate and untreated products obtained from the test results for 5 days at 32 ° C and 85% relative humidity, the preservation of effective oxygen was measured as follows.

Of the untreated products, A is a stabilizer without additives, and B is a product in which only a known stabilizer is added.

Claims (1)

When sodium carbonate and hydrogen peroxide are reacted to prepare sodium percarbonate, as mentioned above in the main text, it is mixed with a well-known stabilizer (magnesium silicate, magnesium sulfate, magnesium oxide, sodium metasilicate or water glass) as a stabilizer. A process for producing stable sodium percarbonate.