A Study of Local Structure Formation in Binary Solutions of 2-Butoxyethanol and Water by Rayleigh Scatterring and Raman Spectra

The concentration dependence of concentration fluctuations at 21, 32, and 42 °C and of Raman spectra at 21 °C were measured for binary solutions of 2-butoxyethanol (BE) and water. The existence of the two kinds of local structures is inferred; clathrate hydrate-like structure g[(H2O)50BE] and aggregate h[(H2O)4BE]. The compositions of these two structures are the same as those of the two phases into which the solution separates above the critical solution temperature. The phase separation is understood to be the end of the growth of the local structures, which already exist well below the critical solution temperature.