hypophosphorous acid

Hypophosphorous Acid – CAS No. 6303-21-5

Hypophosphorous acid, with the chemical formula H₃PO₂ and CAS Number 6303-21-5, is a potent phosphorus oxyacid renowned as a reducing agent in electroless plating, chemical synthesis, and polymer stabilization. This colorless, low-melting oily liquid or deliquescent crystals, typically supplied as a 50% aqueous solution, offers high solubility in water (>1000 g/L) and a strongly acidic pH of 1.0-2.0, enabling efficient hydrogen donation without generating harmful byproducts. With a purity ≥50% (as H₃PO₂), it facilitates uniform metal deposition in nickel plating, phosphonate production for scale inhibition, and antioxidant roles in polyamides, delivering cost-effective performance in corrosive-resistant coatings and water treatment. Its thermal stability up to 108°C boiling point supports versatile processing, while its biodegradability aligns with eco-conscious formulations.

Applications-hypophosphorous acid

Electroless Plating and Coatings

• Nickel Deposition: Used at 20-40 g/L in baths for corrosion-resistant coatings on plastics and metals, ensuring uniform 5-50 µm layers.
• Surface Treatment: Reduces palladium activators for ABS plating in electronics, enhancing adhesion and conductivity.

Chemical Synthesis

• Phosphonate Production: Precursor for amino methylene phosphonic acid at 10-20% in scale inhibitors for boilers and cooling towers.
• Polymer Additives: Stabilizer in nylon 6,6 at 0.5-1% to prevent discoloration and improve melt flow.

Water Treatment

• Reductant for Chromium: Dosed at 100-500 ppm to convert Cr(VI) to Cr(III) in effluents, meeting EPA discharge limits.

Why Choose Our Hypophosphorous Acid?

Our Hypophosphorous Acid is ion-exchanged for phosphite <0.5% and heavy metals <5 ppm, providing superior plating brightness and reduced bath decomposition. Platers report 20% longer bath life and 15% higher deposition rates. Available as 50% aqueous solution for industrial/technical grades, packaged in 25kg carboys or 250kg drums, with customizable concentrations and certifications like ISO 9001 and REACH for global reliability.

Frequently Asked Questions (FAQs)

What is Hypophosphorous Acid?

It is a phosphorus oxyacid with formula H₃PO₂ and CAS 6303-21-5, acting as a reducing agent. It’s a colorless liquid used in plating and synthesis for its hydrogen-donating properties.

How is it used in electroless nickel plating?

Add 25-35 g/L to the plating bath at pH 4.5-5.5 and 85-95°C; it reduces Ni²⁺ to metallic nickel, forming adherent coatings without electricity.

Is Hypophosphorous Acid corrosive?

Yes, its low pH (1-2) requires HDPE or glass storage; dilute solutions (<10%) are manageable with stainless steel equipment.

What is the shelf life of Hypophosphorous Acid?

In sealed, cool storage (<25°C) away from light, the 50% solution remains stable for 12-18 months, with minimal oxidation.

Can Hypophosphorous Acid be used in water treatment?

It effectively reduces heavy metals like chromium at 200-400 ppm, but neutralize post-treatment to prevent acidity in discharges.

Does Hypophosphorous Acid generate gases in reactions?

It evolves hydrogen during reductions, so ventilate; no toxic gases under controlled pH >1.

What packaging options are available for Hypophosphorous Acid?

We provide 25kg HDPE carboys, 250kg plastic drums, and 1000kg IBCs, all acid-resistant and compliant with UN 2835 for corrosives.

For plating recipes, purity specs, or bulk inquiries, our chemical team offers expert assistance.

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