Clathrate Hydrate Formation and Micellization of Tetrabutylammonium 10-Undecenoate

The hydrophobic effect can give rise to both clathrate hydrate formation and micellization, depending on the molecular composition of the solute, temperature, and pressure.However, only a single compound, tetrabutylammonium dodecanoate, TBAD, has been shown to induce both types of self-assembly.Here we examine a second clathrate-forming surfactant.Tetrabutylammonium 10undecenoate, TBAU, is shown to form a clathrate with a hydration number of 22.6 and a melting point of 293.32 ± 0.16 K, and also to form micelles with a critical micelle concentration, CMC, of 0.032 ± 0.004 mol dm -3 at 298.2 ± 0.3 K. Solubilization of a hydrophobic dye, Oil Blue N, by TBAU was compared to a series of tetra-n-alkylammonium 10undecenoates at 296 ± 2 K.The CMC decreased and the solubilization power of the surfactant increased with the number of carbons in the counterion.No special, clathrate hydrate forming effects were evident above the clathrate hydrate melting point.