PHOSPHOROUS ACID (Crystals) CAS Number: 13598-36-2

1. Agriculture

Phosphorous acid itself isn’t a typical fertilizer, but its salts (phosphites) are widely used in agriculture.

Fungicide / Disease Control:

Phosphites are effective against oomycete pathogens like Phytophthora and Pythium.

They work systemically, moving through xylem and phloem to protect the plant internally.

Used as foliar sprays or soil drenches.

Plant Nutrition / Biostimulant:

Provides phosphite ions that plants can partially metabolize.

Enhances stress resistance, vigor, and overall crop health.

Often applied to high-value crops like potatoes, grapes, tomatoes, and ornamental plants.

Advantages:

Rapid uptake and systemic protection.

Can be integrated with fertilization programs.

Reduces pathogen impact without harming beneficial microorganisms.

2. Industrial & Chemical Synthesis

Phosphorous acid is a versatile intermediate in chemical manufacturing:

Production of Phosphites:

Reacts with alcohols to produce trialkyl phosphites.

Phosphites are used as stabilizers for PVC plastics, antioxidants for polymers, and as ligands in catalysis.

Herbicides & Pesticide Precursors:

Intermediate for chemicals like glyphosate and other organophosphorus compounds.

Specialty Chemicals:

Phosphorous acid derivatives are used in flame retardants, corrosion inhibitors, and in industrial coatings.

3. Materials & New Technologies

Emerging applications leverage phosphite chemistry in advanced materials:

Battery Materials:

Certain metal phosphite complexes are being investigated as precursors for electrode materials.

Offers controlled phosphorus content in lithium-ion battery cathodes and other energy-storage materials.

Novel Functional Materials:

Organophosphites are used in polymer modification, additive manufacturing, and high-performance resins.

Can enhance flame retardancy, thermal stability, and chemical resistance.