Synthesis and Quantitative Determination of Gemini Surfactants

Abstract

The intermediate 1-bromo-2-(2-bromoethoxy)ethane was synthesized from diglycol and phosphorus tribromide. Cationic Gemini surfactants, diethyl ether-bis-(dimethyl alkylammonium bromide) were synthesized from the intermediate and tertiary amines with different alkyl chains by using isopropanol as solvent. The reactants were recystallized in the ethyl acetate-ethanol solvent mixture (volume ratio is 2:1), the yields were all up to 70 %. The Gemini surfactants were characterized by infrared and ¹H NMR analysis and were also quantitatively determined by the two phase chemical titration using bromophenol blue as the indicator and chloroform as the phase dispersing agent. The results showed that the purity of the six Gemini surfactants synthesized are greater than 96 % in weight.