Potassium hydrogen phosphate, with the chemical formula K₂HPO₄, is an inorganic compound, commonly found in the form of anhydrous and trihydrate (K₂HPO₄·3H₂O).
Basic properties：
- Appearance: White crystals or powder, easily soluble in water, the aqueous solution is weakly alkaline.
- Solubility: easily soluble in water, insoluble in ethanol.
- pH value: The pH of 1% aqueous solution is about 9.
Main application：
- Food industry: used as quality improver, emulsifier, buffer, etc., for meat, cheese and other products.
- Pharmaceutical field: used as buffer and electrolyte supplement.
- Water treatment: used as water softener and corrosion inhibitor to prevent boiler scale.
- Laboratory: commonly used reagent for buffer solution preparation and chemical analysis.
- Others: also used in textile, papermaking, detergent and other industries.
Preparation method：
It is mainly prepared by the reaction of phosphoric acid with potassium hydroxide or potassium carbonate. The reaction is as follows:
- H₃PO₄ + 2KOH → K₂HPO₄ + 2H₂O
- H₃PO₄ + K₂CO₃ → K₂HPO₄ + CO₂ + H₂O
Safety precautions：
- Inhalation: May irritate the respiratory tract, so please operate in a well-ventilated place.
- Contact: May irritate the skin and eyes, so please wear protective equipment when operating.
- Ingestion: Ingestion of large amounts may cause gastrointestinal discomfort, so please avoid accidental ingestion.
Storage：
It should be stored in a cool, dry, ventilated place, away from acids and flammable materials.
Summary：
Dipotassium hydrogen phosphate is widely used in food, medicine, water treatment and other fields. When using it, attention should be paid to safe operation and storage conditions.