Volumetric properties of (water + diethanolamine) systems

Abstract

Densities of completely miscible (water + methyldiethanolamine) and (water + ethyldiethanolamine) systems have been measured over the full range of compositions at temperatures from 25 to 80°C. Results of these measurements have been used in calculating excess molar volumes and partial molar volumes of each component. We have also identified different measures of the thermal expansion of these systems and have calculated some of these derivative quantities. The partial molar volumes and their derivatives with respect to temperature provide a basis for extending our understanding of molecular interactions in these (water + organic) systems.

Excess properties of (alkyldiethanolamine +H2O) mixtures at temperatures from (298.15 to 338.15) K

“…The position of the minimum becomes more negative from (DEA + H 2 O) to the (MDEA + H 2 O) mixture, while it becomes less negative for the aqueous mixtures of the ethanolamines with bigger alkyl groups (from propyl to n-butyl group). This effect has been also reported in our earlier investigations (4,5) following equations: (4,12) …”

“…(1,2) Densities, excess molar volumes, and excess molar enthalpies of (monoethanolamine, MEA, + H 2 O), (monomethylethanolamine, MMEA, + H 2 O), and (dimethylethanolamine, DMEA, + H 2 O) were studied at T = 298.15 K. (3) Excess molar volumes of aqueous solutions of (MEA + H 2 O), (diethanolamine, DEA, + H 2 O), and (triethanolamine, TEA, + H 2 O) (4) and of (methyldiethanolamine, MDEA, + H 2 O) and (ethyldiethanolamine, EDEA, + H 2 O) (5) were measured from T = (298.15 to 353.15) K. Densities and excess molar volumes of (DMEA + H 2 O) and (diethylethanolamine, DEEA, + H 2 O) were reported at T = (293.15 to 313.15) K. (6) Transport properties of pure ethanolamines (7) and (DEA + H 2 O) and (MDEA + H 2 O) have also been studied. (8) Heat capacities (9) and thermal conductivities (10) (12) and of (monoethylethanolamine,…”

Density and excess molar volumes of aqueous solutions of morpholine and methylmorpholine at temperatures from 298.15 K to 353.15 K

“…The effect of the methyl group on the nitrogen atom has been reflected by lowering the excess molar volume compared with the excess molar volume of the aqueous solutions of morpholine. A similar effect has been seen for the excess molar volume (6,8) and also for excess molar enthalpy. (6,(11)(12)(13) This can be related to the hydrophobic hydration.…”

“…The partial molar volumes of the morpholine and methylmorpholine are calculated by the following: (7,8,(11)(12)(13) …”

“…The water partial molar volumes remain practically constant at 15 cm 3 · mol −1 . In our earlier works, (7,8,(11)(12)(13) it was shown that the partial molar quantities could be calculated by using the following equations:…”