Refractive Indices and Their Related Properties for Binary Mixtures Containing 2-Diethylethanolamine with 1-Propanol and 1-Butanol

Abstract

Experimental refractive index, $$n_{{\text{D}}}$$ , data for eleven binary systems of 2-diethylethanolamine (2-DEEA) + 1-propanol/1-butanol at different temperatures from T = 293.15 to 313.15 K and at atmospheric pressure, over the whole concentration range, are reported. The molar refractions ( $$R_{{\text{m}}}$$ ), molecular radii $$\left( r \right)$$ , reduced molar free volumes $$\left( {{{V_{{\text{m}}} } \mathord{\left/ {\vphantom {{V_{{\text{m}}} } {R_{{\text{m}}} }}} \right. \kern-\nulldelimiterspace} {R_{{\text{m}}} }}} \right)$$ , internal pressure, $$\left( {P_{{\text{int}}} } \right)$$ and the deviations of refractive indices $$\left( {\Delta n_{{\text{D}}} } \right)$$ , molar refraction $$\left( {\Delta R_{{\text{m}}} } \right)$$ , reduced molar free volumes $$\Delta \left( {{{V_{{\text{m}}} } \mathord{\left/ {\vphantom {{V_{{\text{m}}} } {R_{{\text{m}}} }}} \right. \kern-\nulldelimiterspace} {R_{{\text{m}}} }}} \right)$$ , and internal pressure $$\Delta \left( {P_{{\text{int}}} } \right)$$ were also calculated from the experimental data. Nine mixing rules, viz. those of Arago and Biot, Newton, Heller, Gladstone and Dale, Eyring and John, Eykman, Lorentz and Lorentz, Weiner and Oster are used to predict the refractive indices of the binary liquid systems. Among all, the Weiner method (W) is in best agreement with the experimental results.