Imidozoline derivatives as surfactants

Excerpt: Imidazoline surfactants are a special class belonging to the family of cationic surfactants.

Imidazoline surfactants are a special class belonging to the family of cationic surfactants. Cationic surfactants are often quaternary nitrogen salts and used as fabric softeners – dispersing agents and co emulsifiers. Imdidozoline surfactants have a pendant group by which and a hydrocarbon tail making to qualify as a special class of surfactants.

The earlier class of leveling agents were based on cationic surfactants which was further extended to suit other applications like disinfectants and personal care products. These can be classified into fatty amine salts, fatty diamine salts, quaternary ammonium compounds and imidazoline salts. Substituted imidazoline compounds possess additional and special properties such as increased shelf life- better dispersibility and fabric conditioning properties.

Softeners are products when applied to fabrics improve the handle with a pleasant touch, which is achieved by reducing the co- effient of friction between the fibers, yarns or fabrics. Chemically softeners are surface active agents with long chain hydrophobic part and a short chain hydrophilic polar water solubilizing group. Straight chain derivatives are better then branched chains and unsaturation in the fatty alkyl groups reduces softening. Cationic softeners are nitrogenous containing which include imidozoline – amino silicones and quaternary compounds. Conventional softeners contain 2 to 10% of quaternary salts or imidozoline compounds. Imidazolines compounds are second to quaternary ammonium compounds in tonnage of cationic surfactants, produced for fabric softeners. In practice imidazoline compounds are frequently blended with quaternary ammonium compounds to get the degree of fabric softening.

Imidozolene class

Two major classes of amphoteric surfactants are derived from fatty alkyl hydroxyl imidozolenes, which in turn are produced from fatty acids and low molecular weight amines. Because fatty acids are fairly economic, the imidozolene derived amphoacetates tend to be less expensive than the iminopropionates. Most imidozolene derived amphoterics are made from fatty acids reacted with aminoethyethanolamine to produce an amido – functional alkanolamine which then cyclizes to an alkyl hydroxyl ethyl imidozolene. These imidozlenes have proved very useful as intermediates to amphoteric surfactants.

Cationic imidazolines have positive charge on imidazoline molecule and the electrical charge on the molecule makes it unaffected to pH changes. They remain positive in the acidic – neutral and alkaline medium. This qualifies the product as fabric softeners – laundry softeners – and dispersants and the group include:

Hydroxyethyl imidazolines

These type of cationic imidazolines are based on fatty acid/aminoethyl ethanolamine in the molar ratio of 1:1 and are used as rheology modifiers, oil soluble, water soluble salts and adhesion promoters in lubricants, paint and ink industries.

Amidoethyl imidazolines

These type of cationic imidazoline are based on fatty acid/diethylenetriamine in the molar ratio of 1:1 for applications as fabric softeners, acid stable detergents and flocculating agents. e.g. amidoethyl imidazoline. Chemically imidazoline compounds belong to the heterocyclic compounds containing five membered ring having two nitrogen atoms in the ring. Some imidozoline derivatives possess re wettability which is an important requirement in Terry Towel finishing. The positive charge of imidozoline salts has the capacity to neutralize certain silicates and anionic detergents from effluent streams.


Imidozolene synthesized with an optimized process have good laundry and textile finishing. In addition, the chemical structure of imidozolene compounds makes it possible for numerous applications.

Author Details

C. N. Sivaramakrishnan