Phenylphosphine oxide

Updated: 2026-08-06

Overview

Phenylphosphine oxide is an organophosphorus compound widely used in chemical synthesis and industrial applications. It features a phosphorus atom bonded to a phenyl group and two hydrogen atoms, with an oxygen atom double-bonded to the phosphorus. This structure makes it a versatile intermediate in the production of flame retardants, pharmaceuticals, and specialty chemicals. Its role as a ligand in coordination chemistry is particularly notable, where it facilitates the formation of metal complexes. The compound is typically supplied as a white crystalline solid and must be handled with care due to its hygroscopic nature.

Physical and Chemical Properties

Phenylphosphine oxide is a stable compound under normal conditions but can absorb moisture from the air, necessitating proper storage. It has a melting point of approximately 70-72°C and is soluble in water and polar organic solvents like ethanol and acetone. The molecular weight is 124.08 g/mol, and its structure includes a polar P=O bond, contributing to its reactivity. The compound's stability and solubility make it suitable for various chemical reactions, including nucleophilic substitutions and reductions. However, its hygroscopic nature means it should be stored in airtight containers to prevent degradation.

Main Applications

Phenylphosphine oxide serves as a key intermediate in the synthesis of flame retardants, where it enhances the fire resistance of materials like plastics and textiles. It is also used in the pharmaceutical industry to produce active ingredients and in agrochemicals for crop protection. In coordination chemistry, it acts as a ligand, forming stable complexes with transition metals. These complexes are valuable in catalysis and material science. Additionally, the compound is employed in the production of specialty chemicals, including surfactants and adhesives.

Safety and Storage

Phenylphosphine oxide should be handled with care to avoid inhalation or skin contact, which can cause irritation. Personal protective equipment, including gloves and goggles, is recommended during use. The compound is stable but hygroscopic, so it must be stored in a cool, dry place away from oxidizing agents. In case of spillage, absorb the material with an inert substance and dispose of it according to local regulations. Proper ventilation is essential when working with the compound to prevent the accumulation of vapors.

B2B Procurement Guide

When procuring phenylphosphine oxide, verify the CAS number (637-51-4) and purity specifications to ensure quality. Suppliers typically offer the compound in various grades, with prices ranging from approximately $50 to $200 per kg, depending on purity and quantity. Bulk purchases may qualify for discounts, so negotiate with suppliers for better rates. Ensure the material is packaged in airtight containers to prevent moisture absorption during transit. Reliable suppliers often provide technical data sheets and certificates of analysis.