Potassium Phosphate Dibasic (K₂HPO₄) is an inorganic salt that serves as a crucial compound in pharmaceuticals, food production, agriculture, and industrial processes. As a buffering agent, nutrient source, and stabilizer, Potassium Phosphate Dibasic plays a vital role in maintaining pH balance and providing essential potassium and phosphorus in various formulations. This white, water-soluble powder has become indispensable across multiple industries due to its unique chemical properties and versatility.
Chemical and Physical Properties
Potassium Phosphate Dibasic exhibits several important characteristics:
Basic Properties
- Chemical Formula: K₂HPO₄
- Molecular Weight: 174.18 g/mol
- Appearance: White crystalline powder
- Solubility: Highly soluble in water (149 g/100 mL at 20°C)
- pH: 8.5-9.5 (1% aqueous solution)
- Density: 2.44 g/cm³
Structural Features
- Forms orthorhombic crystals in anhydrous state
- Typically available as trihydrate (K₂HPO₄·3H₂O)
- Contains two potassium ions for each hydrogen phosphate anion
Chemical Behavior
- Acts as a weak base in solution
- Excellent buffering capacity in pH range 7.0-9.0
- Converts to potassium phosphate tribasic when heated
- Reacts with acids to form monobasic phosphate
Production Methods
Industrial production of Potassium Phosphate Dibasic involves several approaches:
1. Neutralization Process
- Reaction of phosphoric acid with potassium hydroxide:
H₃PO₄ + 2KOH → K₂HPO₄ + 2H₂O - Precise pH control during neutralization
2. Crystallization from Solution
- Evaporation of aqueous solutions
- Temperature-controlled crystallization
- Centrifugation and drying of final product
3. Purification Techniques
- Recrystallization for high-purity grades
- Ion exchange for removal of impurities
- Filtration to ensure product consistency
Industrial Applications
Potassium Phosphate Dibasic serves critical functions across multiple sectors:
1. Pharmaceutical Industry
- Buffer agent in injectable formulations
- Electrolyte replenisher in IV solutions
- Excipient in tablet manufacturing
- pH adjuster for ophthalmic preparations
2. Food Industry
- Emulsifier in processed cheeses
- Stabilizer in evaporated milk
- Acidity regulator in beverages
- Nutrient supplement in food products
3. Agricultural Uses
- Water-soluble fertilizer component
- Hydroponic nutrient solution ingredient
- Soil conditioner for pH adjustment
4. Biotechnology and Research
- Buffer component in cell culture media
- Reagent in molecular biology
- Mobile phase additive in chromatography
5. Industrial Processes
- Corrosion inhibitor in water treatment
- Dispersing agent in ceramic production
- Flame retardant in certain materials
Technical Specifications and Grades
Potassium Phosphate Dibasic is available in various purity grades:
| Grade | Purity | Typical Applications |
|---|---|---|
| Food | ≥98% | Food additives, processing |
| Pharmaceutical | ≥99% | Drug formulations |
| ACS Reagent | ≥99.5% | Laboratory analysis |
| Industrial | ≥97% | Technical applications |
Safety and Handling
Proper protocols ensure safe use of Potassium Phosphate Dibasic:
Health Considerations
- Eye Contact: Causes irritation – flush with water
- Skin Contact: May cause mild irritation
- Ingestion: Harmful in large quantities
- Inhalation: Dust may irritate respiratory tract
Storage Requirements
- Keep in tightly sealed containers
- Store in cool, dry conditions
- Separate from strong acids
Regulatory Status
- FDA GRAS (Generally Recognized as Safe) for food use
- Listed in major pharmacopeias (USP, EP, JP)
- Compliant with REACH regulations
Comparison with Related Phosphate Salts
Potassium Phosphate Dibasic offers distinct advantages:
| Parameter | K₂HPO₄ | Na₂HPO₄ | KH₂PO₄ | K₃PO₄ |
|---|---|---|---|---|
| pH (1% sol.) | 8.5-9.5 | 8.0-11.0 | 4.4-4.9 | 11.0-12.0 |
| Potassium Content | High | None | High | Very High |
| Primary Buffering Range | pH 7-9 | pH 7-9 | pH 4-5 | pH 11-12 |
| Hygroscopicity | Low | Moderate | Moderate | High |
Quality Control and Analysis
Rigorous testing ensures Potassium Phosphate Dibasic meets specifications:
Standard Tests
- Assay: Acid-base titration
- Heavy Metals: ICP-MS analysis
- Loss on Drying: Moisture content
- Insoluble Matter: Gravimetric method
Advanced Characterization
- XRD: Crystal structure analysis
- FTIR: Functional group verification
- HPLC: Purity assessment
Market Trends and Future Outlook
The global Potassium Phosphate Dibasic market shows steady growth due to:
Demand Drivers
- Expansion of pharmaceutical industry
- Increasing food processing activities
- Growth in hydroponic agriculture
- Advances in biotechnology
Emerging Opportunities
- High-purity grades for electronics
- Specialty fertilizer formulations
- Advanced drug delivery systems
Challenges
- Raw material price fluctuations
- Regulatory changes in food additives
- Competition from alternative buffers
Conclusion
Potassium Phosphate Dibasic remains an essential chemical compound with wide-ranging applications across multiple industries. Its excellent buffering properties, combined with potassium and phosphate content, make it invaluable in pharmaceutical formulations, food processing, agricultural products, and industrial applications.
As technological advancements continue in life sciences and industrial chemistry, the demand for high-quality Potassium Phosphate Dibasic is expected to grow. Future developments will likely focus on ultra-pure grades for specialized applications and sustainable production methods to meet evolving environmental standards.
