Its chemical formula is C24H38O4 (structural formula: o-C₆H₄(COOCH₂CH(C₂H₅)C₄H₉)₂) and CAS number is 117-81-7 (note: di-n-octyl phthalate, DNOP, CAS 117-84-0, is its linear isomer). It is a colorless, transparent, and slightly odorous viscous liquid with excellent compatibility, high plasticizing efficiency, and low volatility, long dominating the general-purpose plasticizer market despite growing regulatory scrutiny over its potential endocrine-disrupting properties.

Key Applications

Primary PVC Plasticizer: The most widely used application; it imparts excellent flexibility, low-temperature resistance, and processability to PVC. Used in films, cables, pipes, artificial leather, flooring, and general-purpose soft PVC goods. Electrical-grade DOP enhances insulation for wires/cables.

Polymer Modifier: Modifies ABS, PS, and rubber to improve toughness, impact resistance, and processability; used in thermoplastic elastomers (TPEs) for elasticity and durability.

Coatings & Adhesives: Acts as a coalescing agent and plasticizing solvent in industrial coatings, automotive paints, and adhesives, improving film formation, adhesion, and water/chemical resistance.

Other Uses: Used as a gas chromatography (GC) stationary phase, a plasticizer in printing inks, and a standard reference material for analytical chemistry.