What is potassium dihydrogen sulfate used for?

Potassium dihydrogen sulfate is widely used in the pharmaceutical industry. It is a white powder that is easily soluble in water. In the pharmaceutical industry, it is a culture medium for the manufacture of penicillin and streptomycin. It is also a deironing agent for talc and a pH regulator. It is often used as a culture medium in water treatment. In addition, it has a good application in chemical analysis in the food industry. Let us learn about this aspect below.

Dipotassium hydrogen phosphate is an inorganic compound with the appearance of white crystals or amorphous white powder. It is easily soluble in water, and its aqueous solution is slightly alkaline. It is slightly soluble in alcohol, hygroscopic, and self-dissolves at high temperatures. The relative density is 2.338, and at 204°C the molecule dehydrates and converts into potassium pyrophosphate. The pH value of 1% aqueous solution is 8.9. It is mainly used in medicine, fermentation, bacterial culture and the preparation of potassium pyrophosphate, etc.

What is potassium dihydrogen sulfate used for?

1. Mainly used in the pharmaceutical industry (culture medium for penicillin and streptomycin), and can also be used as a deironing agent and pH regulator for talc.

2. Used as water treatment agent, microorganism and fungus culture agent.

3. In the food industry, it is used as a raw material for alkaline water in the preparation of pasta products, a fermentation agent, a flavoring agent, a leavening agent, a mild alkaline agent for dairy products, and a yeast food. It is sometimes added to milk tea powder. It can also be used as a feed additive.

4. Used as a buffer in chemical analysis, in metal phosphating and as an electroplating additive.

Production method: It is produced by neutralizing phosphoric acid with caustic potash solution in industrial production. It can also be produced by neutralizing phosphoric acid with potassium carbonate solution first and then with caustic potash solution.

1. Neutralization method

Prepare 30% aqueous solution of solid caustic potash, clarify and filter to remove impurities, add to the corrosion-resistant reaction tank after measurement, slowly add appropriate amount of 50% phosphoric acid solution under stirring, carry out neutralization reaction at 90-100°C, and control the pH of the reaction end point to 8.5-9.0 (until phenolphthalein turns red as an indicator). Heat to 120-124°C for concentration, and filter to remove insoluble matter after the solution concentration reaches the required range. The clarified filtrate is cooled to below 20°C to precipitate crystals, which are then separated by centrifugation and slightly air-dried to obtain the finished product of dipotassium hydrogen phosphate. The reaction equation is as follows:

H3PO4+2KOH→K2HPO4+2H2O

The mother liquor is filtered and returned to the process for use.

2. Potassium carbonate method

Under constant stirring, potassium carbonate solution is added to 30% phosphoric acid solution to react. The neutralization endpoint is pH 8.5-9.0 (phenolphthalein indicator just turns red). The neutralized solution is concentrated to 120-124°C and filtered to remove insoluble matter. It is then cooled to below 20°C for crystallization. The product is obtained by centrifugation and drying, and the mother liquor is sent to the neutralization process for reuse [2]. The reaction equation is as follows:

K2CO3+H3PO4→K2HPO4+H2O+CO2↑