Synthesis, Surface Activities and Toluene Solubilization by Amine-oxide Gemini Surfactants

A series of amine-oxide gemini surfactants featuring amide groups [ N , N ’-dimethyl- N , N ’-bis(2-alkylamideethyl)-ethylenediamine oxide (alkyl = C 11 H 23 , C 13 H 27 , C 15 H 31 , C 17 H 35 )] have been synthesized via a three-step synthetic route, and their chemical structures were confirmed by mass spectra, FTIR and 1 H-NMR spectra. The surface activities of these compounds have been measured. The results show that these synthesized amine-oxide gemini surfactants reduced the surface tension of water to a minimum value of approximately 26.91 mN m −1 at a concentration of 2.92 × 10 −5 mol L −1 . Furthermore, their critical micelle concentration (CMC) values and solubilization of toluene decrease with an increase of the hydrophobic chain length from 12 to 18. Isoelectric point measurements revealed that their p I values range from 4.0 to 10.5.