Solution Behavior of Amide Types of Chemocleavable Nonionic Surfactants Bearing a 1,3-Dioxolane Ring

We have been investigating the preparation process and the properties of a series of acid- and alkali-cleavable surfactants which are designed to chemically decompose into non-surface active species under mild conditions after fulfilling their original functions such as emulsification, solubilization, micellar catalytic activity.  The decomposition properties can be controlled through pH adjustment of the solution.
In this work, amide types of chemocleavable surfactants bearing a 1,3-dioxolane ring were prepared by acid-catalyzed condensation of diethyl tartrate with fatty ketones, followed by a reaction with amine without any expensive reagents or special equipment.  We confirmed that they have good surface-active properties.  Biodegradability of the surfactants was evaluated by an oxygen consumption method according to the guidelines which was based upon the OECD 301C with activated sludge.  Their detergency on artificially soiled cotton cloth was better than the reference detergent in hard water according to the Japan Industrial Standard Method.  The reference detergent consisted of sodium n-dodecylbenzenesulfonate, which is a popular component in the commercial detergents.  As low molecular-weight gelators are industrially attractive materials, we discussed the gel-forming properties in various solvents.  The viscosity of the chloroform solution containing the chemocleavable surfactant was higher than that of the blank solvent.  In the case of 5 wet% chloroform solution, the viscosity become drastically high at 25°C and become low at 40°C, which is the typical characteristics of low molecular-weight gelators.