Amine Oxides

AbstractAmine oxides, known asN‐oxides of tertiary amines, are classified as aromatic or aliphatic, depending on whether the nitrogen is part of an aromatic ring system or not. This structural difference accounts for the difference in chemical and physical properties between the two types. The higher aliphatic amine oxides are commercially important because of their surfactant properties and are used extensively in detergents. Amine oxides that have surface‐acting properties can be further categorized as nonionic surfactants; however, because under acidic conditions they show cationic properties, they have also been called cationic surfactants. Most amine oxides undergo thermal decomposition between 90 and 200°C. Aromatic amine oxides, have some pharmaceutical importance, do not demonstrate surface‐acting properties and are more resistant than aliphatic amine oxides to reduction. Linear alpha‐olefins are the source of the largest volume of aliphatic amine oxides. Fatty alcohols and fatty acids are also used to produce amine oxides. Amine oxides used in industry are prepared by oxidation of tertiary amines with hydrogen peroxide solution. Amine oxides are used in the detergent, organic synthesis, textile, and pharmaceutical industries. Aliphatic amine oxides range from practically nontoxic to slightly toxic. Among the aromatics, 4‐nitroquinolineN‐oxide is a powerful carcinogen, producing malignant tumors on the skin of mice. 2‐Methyl, 2‐ethyl, and 6‐chloro derivatives of 4‐nitroquinoline oxide are also carcinogens.