ENTHALPIES OF TRANSFER OF UBIQUINONE-0 FROM WATER TO AQUEOUS SURFACTANT SOLUTIONS AT VARIOUS TEMPERATURES

摘要

Mixing and dilution enthalpies of aqueous solutions of 2,3-dimethoxy-5-methyl-1,4-benzoquinone (UQ(0)) and of N,N-dimethyl-dodecylamine-N-oxide (DDAO) were measured and used to calculate the enthalpies of transfer Delta H(W --> W + S) of UQ(0) from water to DDAO aqueous solutions at 20 degrees, 25 degrees, 30 degrees, and 35 degrees C. From the dependence of Delta H(W --> W + S) on surfactant concentration, the distribution constant between aqueous and micellar phases and the standard transfer enthalpy of UQ(0) from water to DDAO micelles were evaluated along with the standard transfer free energy and entropy. The approach used required knowledge of the CMC and micellization enthalpy at each temperature. Thus, the thermodynamics of micellization of DDAO was studied by means of dilution enthalpy measurements at the several temperatures. [References: 32]