Isononanoic acid

Isononanoic acid (CAS 693-19-6), also known as isopelargonic acid or 7-methyloctanoic acid, is a branched-chain C9 fatty acid produced primarily through the oxo synthesis of isooctene. It carries no assigned E-code and is distinct from linear nonanoic acid in both reactivity and physical behaviour.

In lubricant formulations, isononanoic acid serves as a precursor to metal soap complexes that provide corrosion inhibition on ferrous and non-ferrous surfaces. In coatings and plasticiser production, it reacts with polyols or alcohols to form esters that reduce polymer rigidity and improve film flexibility without migrating rapidly from the matrix.

Isononanoic acid is supplied as a technical-grade liquid and is subject to REACH registration requirements within the EU. Producers typically offer it in intermediate bulk containers and road tankers. Buyers should confirm acid value and purity specifications directly with the supplier, as grade standards vary by application.