Synthesis and Physico-Chemical Studies of Ester-Quat Surfactants in the Series of (Dodecanoyloxy)propyl n-Alkyl Dimethyl Ammonium Bromide

摘要

Ester-quat surfactants in the series of (dodec-anoyl oxy) propyl n-alkyl dimethyl ammonium bromide referred to here as LC3Cm (where m is the hydrocarbon chain lengths 8, 12 and 14) were synthesized and characterized by the usual spectroscopic methods (NMR, IR, MS...). Their physico-chemical properties were investigated by surface tension and conductimetric measurements. From surface tension measurements, isotherms and thermodynamic adsorption parameters were determined. The critical micelle concentration (CMC), the degree of counter ion dissociation (α) of micelles in the water and the standard Gibbs free energy (ΔG_m~0, of micellization were also determined by conductimetric measurements. The results obtained from both methods were compared to the similar surfactants in the series of quaternary ammonium surfactants. Optical microscopy was also used to study the behavior of anhydrous surfactants and the binary water/ surfactant system as a function of temperature.