Refractive indices of binary mixtures of diglycolamine - water at various temperatures

Abstract

In this work, the refractive indices n_D, refractive index deviations Δ n_D, molar refractions R_m and excess molar refractions R^E_m were determined over the full range of compositions for the Diglycolamine-water binary mixture. Experimental measurements of these properties were carried out at atmospheric pressure and at temperatures ranging from 293.15 to 333.15 K. Excess molar refractions R^E_m and refractive index deviations Δ n_D have been fitted to the polynomial Redlich-Kister equation. The refractive indices have been compared with those predicted by the mixing rules proposed by: Lorentz-Lorenz (L-L), Gladstone- Dale (G-L), Eykman (E), Arago-Biot (A-B), Eyring-John (E-J), Bruggeman (B), and Oster (OS), in order to verify their validity for the Diglycolamine-water binary system. The experimental values of the refractive indices agree well with all the previous relationships, with the relationship of Oster (OS) and Gladstone-Dale (G-L) with which better results are obtained.