Synthesis and Micellization of Organosilicon Gemini Quaternary Ammonium Surfactants.

A novel class of organosilicon gemini quaternary ammonium surfactant alkyl- α, ω-bis(diethyl-methyl-dimethoxy-silopropyl ammonium bromide) ( α, ω = 1,4; 1,6; 1,8) was synthesized and characterized by H-nuclear magnetic resonance (NMR) and elemental analysis. It is found that the quaternization reaction has two steps: first single quaternization and then double quaternization. The effect of solvent on convert ratio has the following sequence: polar aprotic solvents > polar protic solvents > aromatic solvents. The electrical conductivity of aqueous solution was measured at 20, 25, 30 and 35 °C, and the thermodynamic properties of $$ \Delta H_{m}^{0} $$ , $$ \Delta G_{m}^{0} $$ and $$ T\Delta S_{m}^{0} $$ were calculated according to the mass action model and Gibbs equation. It is shown that the enthalpy driven and entropy driven are almost equal in the micellization of [SiC-4-SiC]Br and [SiC-6-SiC]Br, but in the micellization of [SiC-8-SiC]Br, the enthalpic contribution becomes significant and the effect of thermal is greater than the degree of order in the micellization. [ABSTRACT FROM AUTHOR]