Ozone-cleavable gemini surfactants. Their surface-active properties, ozonolysis, and biodegradability

A series of bis(sulfonate) or bis(carboxylate) types of double-chain surfac tants (gemini surfactants) containing carbon-carbon double bond(s) in their lipophilic chains and/or the connecting part were prepared with the intent ion of developing high-performance surfactants having a decomposition chara cter toward ozone. Some profiles with respect to the structural effect of t he double bond(s) on the surface-active properties of these gemini types of surfactants were revealed as follows: (1) the displacement of a C-C bond b y a C=C bond in the connecting part made a positive contribution both to mi cellar formation and to the effectiveness and efficiency of adsorption on t he surface; (2) in contrast to this, a C=C bond in the lipophilic chains of gemini surfactants made a negative contribution to these properties. Ozono lysis of these gemini surfactants was easily accomplished by passing ozone through their micellar aqueous solutions followed by successive reduction o f the resulting mixtures with NaBH4. A remarkable change in foaming propert ies was observed before and after the ozonolysis; that is, foam stability o f all examined ozonolytic products was extremely low. Finally, biodegradabi lity of some gemini surfactants and their ozonolytic product by activated s ludge was estimated. Their degradabilities were much higher than that of so dium dodecyl-benzenesulfonate and were comparable to that of sodium 1-dodec anesulfonate under the same conditions.