What is Monopotassium Phosphate CAS 7778-77-0?

Monopotassium phosphate, commonly called MKP, is the monobasic potassium salt of phosphoric acid with the formula KH2PO4. It is supplied as white crystals or powder and used as a water-soluble fertilizer, buffer and fermentation nutrient.

Why is MKP used in agriculture and fertigation?

MKP is a highly water-soluble source of both phosphorus and potassium with no nitrogen or sodium. Fertilizer-grade material is commonly labeled 0-52-34 and is used in foliar sprays, drip irrigation and soilless production during flowering, fruiting and root development.

Why is Monopotassium Phosphate useful as a pH buffer?

Monopotassium phosphate and its corresponding dipotassium salt form a classic phosphate buffer system. This helps maintain stable pH in biochemical, fermentation and analytical applications.

How soluble is MKP and what is its solution pH?

MKP dissolves readily in water, with solubility commonly cited around 22.6 g/100 mL at 20 C. A 1% solution is mildly acidic, typically around pH 4.3-4.8, which is useful for certain tank mixes and buffered formulations.

What are the main non-fertilizer applications of CAS 7778-77-0?

Beyond agriculture, MKP is used as a buffer, fermentation nutrient, food and beverage processing ingredient and chemical intermediate. Food or fermentation applications require a grade that meets the relevant purity and impurity limits.

Which specifications should I check before ordering Monopotassium Phosphate?

Confirm KH2PO4 content, P2O5, K2O, moisture, water-insoluble matter, chloride, iron, heavy metals and pH. Technical and agricultural water-soluble grades may have different impurity limits from food or fermentation grades.

Monopotassium Phosphate CAS 7778-77-0

Monopotassium Phosphate (CAS 7778-77-0) is a water-soluble inorganic salt utilized as a high-efficiency phosphorus and potassium fertilizer in agricultural fertigation systems and a buffering agent in food processing. Chemically identified as Potassium dihydrogen phosphate or MKP, this colorless crystalline solid functions to lower pH levels in alkaline mixtures and provide rapidly absorbed nutrients for root development. As a high-purity Potassium acid phosphate source, it is integrated into hydroponic nutrient solutions and foliar sprays to enhance flowering and fruit quality. We ensure bulk supply capabilities for this material, providing access to competitive factory pricing and customized specifications to meet specific solubility and mesh size requirements. Full technical documentation, including MSDS, TDS, COA, is available to support compliance and safety protocols.

CAS: 7778-77-0
Synonyms: Potassium dihydrogen phosphate, MKP, Potassium acid phosphate, Monobasic potassium phosphate
Einecs: 231-913-4
Molecular Formula: KH2PO4
Grade: Tech Grade / Agriculture Grade (Water Soluble)
Package: 25kg PP/PE woven bags, kraft paper bags, or 1000kg Jumbo bags (Customizable)

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Product Description

Monopotassium Phosphate is a white, odorless crystalline powder that dissolves rapidly in water. It acts as a high-quality compound fertilizer with an N-P-K ratio typically equivalent to 0-52-34. Due to its low salt index and high purity (≥99%), it is exceptionally safe for foliar applications and drip irrigation systems, posing no risk of leaf burn or root damage when used correctly.

Beyond agriculture, it is widely used in the chemical industry as a buffering agent, a culture medium agent for fermentation, and a raw material for producing potassium meta-phosphate.

1 Physicochemical Properties

2 Applications

3 Storage Conditions

4 Safety Precautions

Physicochemical Properties

Parameter	Specification (Tech/Agri Grade)
Appearance	White Crystal or Crystalline Powder
Main Content (as KH₂PO₄)	≥ 99.0%
Phosphorus Pentoxide (P₂O₅)	≥ 51.5% – 52.0%
Potassium Oxide (K₂O)	≥ 34.0%
Moisture	≤ 0.2%
Water Insoluble Matter	≤ 0.1%
pH Value (1% Solution)	4.3 – 4.8
Chloride (Cl)	≤ 0.2%
Iron (Fe)	≤ 0.003% (30 ppm)
Heavy Metals (as Pb)	≤ 0.005% (50 ppm)
Solubility	~22.6g/100ml water at 20°C

Applications

Agriculture (Fertilizer):
- Foliar Spray: Used to supplement P and K during critical growth stages (blooming and fruit setting) to improve fruit quality and sugar content.
- Fertigation: Ideal for hydroponics and drip irrigation due to its excellent solubility and acidic pH, which helps keep drippers clean.
- Fungicide Effect: When mixed correctly, it can help control powdery mildew on certain crops.
Industrial Fermentation: Used as a nutritional agent and buffering regulator in the fermentation of yeast, bacteria, and other microorganisms.
Chemical Industry: Acts as a buffering agent for pH regulation in chemical reactions.
Food Processing: (If Food Grade specified) Used as a sequestering agent, fermentation food additive, and flavoring agent.

For a related potassium fertilizer raw material with a different nutrient profile, see Potassium Sulfate.

Storage Conditions

Environment: Store in a cool, dry, and ventilated warehouse.
Moisture Control: The product is stable but should be kept away from water and high humidity to prevent caking.
Packaging: Keep bags tightly closed when not in use.
Segregation: Store separately from toxic or hazardous materials.

Safety Precautions

General: MKP is considered safe and non-toxic for general handling.
Protection: Wear standard industrial protective gear (gloves, safety glasses) to prevent dust irritation.
Eye Contact: Rinse thoroughly with water if dust enters the eyes.
Skin Contact: Wash with soap and water.
Inhalation: Avoid breathing dust; use in a ventilated area.

FAQ - Technical & Supply Chain

Q:
What is Monopotassium Phosphate CAS 7778-77-0?

A: Monopotassium phosphate, commonly called MKP, is the monobasic potassium salt of phosphoric acid with the formula KH2PO4. It is supplied as white crystals or powder and used as a water-soluble fertilizer, buffer and fermentation nutrient.
Q:
Why is MKP used in agriculture and fertigation?

A: MKP is a highly water-soluble source of both phosphorus and potassium with no nitrogen or sodium. Fertilizer-grade material is commonly labeled 0-52-34 and is used in foliar sprays, drip irrigation and soilless production during flowering, fruiting and root development.
Q:
Why is Monopotassium Phosphate useful as a pH buffer?

A: Monopotassium phosphate and its corresponding dipotassium salt form a classic phosphate buffer system. This helps maintain stable pH in biochemical, fermentation and analytical applications.
Q:
How soluble is MKP and what is its solution pH?

A: MKP dissolves readily in water, with solubility commonly cited around 22.6 g/100 mL at 20 C. A 1% solution is mildly acidic, typically around pH 4.3-4.8, which is useful for certain tank mixes and buffered formulations.
Q:
What are the main non-fertilizer applications of CAS 7778-77-0?

A: Beyond agriculture, MKP is used as a buffer, fermentation nutrient, food and beverage processing ingredient and chemical intermediate. Food or fermentation applications require a grade that meets the relevant purity and impurity limits.
Q:
Which specifications should I check before ordering Monopotassium Phosphate?

A: Confirm KH2PO4 content, P2O5, K2O, moisture, water-insoluble matter, chloride, iron, heavy metals and pH. Technical and agricultural water-soluble grades may have different impurity limits from food or fermentation grades.

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