Synthesis of some New Quaternary Ammonium Compounds.

Abstract
Four cationic surfactants were prepared by condensing fatty acid methyl
diethanolamine derivatives (C6, C10, C12, C18) with stoichiometric amounts of
trimethyl chlorosilane. The surface properties and parameters were
investigated to find the relationship between the structure of the hydrophobic
portion of such compounds and their efficiency toward solubilization. The
properties studied included surface excess concentration (Γmax), critical
micelle concentration (cmc), free energy of micellization (ΔGo
mic) and
adsorption (ΔGo
ads) in addition to the surface tension (γcmc) at cmc and
effectiveness (Πcmc). The values of Γmax, ΔGo
mic and ΔGo
ads were found to
increase with increasing number of chain length, while cmc and minimum
surface area occupied by one molecule (Amin) were decreased. Solubilization
effect of these surfactants on paraffin oil as a non polar solubilizate and
biodegradability were studied.