Alkyl amine oxide surfactants are a versatile class of surfactants used in both detergents and cosmetics. They are non-ionic in character and compatible with cationic and anionic surfactants. Below is a detailed overview of their chemistry and applications by Norman Lowe, Senior Technical Consultant HPC and Industrial at HARKE UK & Ireland.
Chemistry
Alkyl amine oxides are prepared by the reaction of a tertiary alkyl amine with hydrogen peroxide:
R-N(CH3)2 + H2O2 = R-N(CH3)2→O + H2O
R = C8 to C18 (although higher chain lengths are produced for specialist applications)
An alternative is to use an alkyl ‘Amidopropyl amine’:
R.C(O)-NCH2)3.NCH3)2 + H2O2 = R.C(O)-NH(CH2)3.N(CH3)2→O + H2O
R = C8 to C18 (or beyond)
Another is to use an ethoxylated tertiary alkyl amine:
RN(E/O)2n + H2O2= R N(E/O)2n →O + H2O
R = C8 to C18 (or beyond)
Applications
Detergent Applications
Alkyl amine oxides have a high tolerance to electrolytes and alkalis, making them very suitable for heavy-duty detergent systems. Foaming is adjusted by carbon chain length, with C10 being lower foaming than C12-14. Oleyl (C18:1) cuts can be used as solubilisers or emulsifiers.
They are used in high caustic abattoir cleaners, caustic oven cleaners, both light and heavy-duty traffic film removers (from cars to trucks to trains). Alkyl amine oxides are also stable in hypochlorite and peroxy bleach systems, and are a major component in sodium hypochlorite thickening systems (household thick bleach).
Short chains are lower foaming but maintain a high level of detergency and also act as hydrotropes.
They also find use in household hand dishwash detergents as a co-surfactant, foam booster and stabiliser.
Cosmetics
Alkyl amine oxides are used as foam boosting agents, which are very useful in greasy hair shampoos. Higher chain length adducts like C18:1 (Oleyl) can act as conditioning agents. They help to solubilise actives, and another effect is that they can ‘shield’ cationic surfactants into anionic systems. This enables the formulation of 2-in-1 conditioning shampoos using standard cationic conditioning agents such as CTAC or even BTAC. This effect can also be adapted for use in vehicle wash systems to impart rapid rinse properties.
MACKAMINE® Grades Available from HARKE UK & Ireland
We are pleased to supply a range of MACKAMINE® amine oxides from Verdant:
- Mackamine® C8 (Octylamine Oxide, 40% active, >95% C8): Low foaming, caustic stable, excellent hydrotrope.
- Mackamine® 654 (Decylamine Oxide, 40% Active, >95% C10): Low foaming, for surface cleaners, CIP, and hydrotropic properties.
- Mackamine® CS (Cocamine Oxide, 30% Active, 56% C12, 22% C14, 10% C16, 12% C18): Used for detergent cleaners, TFRs, and thickening hypochlorite bleach.
- Mackamine® CG (Cocamine Oxide, 30% Active): A variant of Mackamine® CS.
- Mackamine® LA (Lauramine Oxide, 30% Active, 72% C12, 28% C14): Suitable for hand dish wash liquids, shampoo, and body wash.
- Mackamine® MY (Myristylamine Oxide, 25% Active, >96% C14).
- Mackamine® C14 (Myristylamine Oxide, 30% active): A higher active variant of Mackamine® MY, used for thickening hypochlorite, shampoos, and body wash.
- Mackamine® CAO-E-36 (Cocamidopropylamine Oxide, coconut oil-based): For hand dishwash liquids, liquid hand soaps, shampoos, and body wash.
These are the standard grades, but not all the variants that are possible. Products are also available with a range of chain length variations which have been developed to meet exacting customer specifications. Bespoke products can also be discussed.
Coconut-derived and Mass Balance grades are available.
HARKE UK & Ireland’s technical department is very experienced in the uses of amine oxides and has developed many formulations covering all areas of application of these products over many years, as well as developing novel uses in certain application areas.
Please contact us if you want to discuss your particular application area in depth or make use of our extensive formulary and technical expertise.
