Phenyl Acetic Acid (PAA)

Phenylacetic acid, also known as phenylethanoic acid or α‑toluic acid, is an organic compound with the molecular formula C₆H₅CH₂COOH. It consists of a phenyl ring attached to a carboxylic acid group, and typically appears as a white to pale yellow crystalline solid or flakes. 

It serves as a key precursor for Penicillin G, where fungi rely on an external supply of phenylacetic acid to form the antibiotic’s side chain. It is also used in the production of diclofenac and in treating acute hyperammonemia. Owing to its naturally sweet, honey-like aroma, it finds applications in perfumes, cosmetics, soaps, and food flavorings.