Osmotic coefficient measurements have been reported for binary aqueous solutions of urea (0.11400 to 1.03192 molkg1) and ternary aqueous solutions containing a fixed concentration (0.10065 molkg1) of polyethylene glycol4000 (PEG4000) and varying the concentrations of urea (0.03882 to 0.70509 molkg1) at 298.15 K using vapour pressure osmometry. For binary (urea + water) system, using experimental osmotic coefficient data, the activity and activity coefficient of urea and water are calculated and further activity data are processed to obtain the Gibb's free energy change on mixing and excess Gibb's free energy change on mixing. The water activities for studied ternary system (Water + 0.10065 molkg1 PEG4000 + Urea) were calculated and used to obtain the activity coefficient of PEG4000 and urea. The transfer Gibbs free energies of PEG4000 from water to an aqueous urea solutions ( Gtr1 ) and that of urea from water to an aqueous PEG4000 solutions ( Gtr2 ) have been calculated using the activity data. The pair and triplet interaction parameters are estimated by applying McMillanMayer theory of virial coefficients to the data of transfer free energy. The salting constant (ks) value and equilibrium constant (log K) value have been estimated for PEG4000urea complexation at 298.15 K. All these results are discussed in light of binding equilibria and water structure alteration concepts. It has been shown that hydrophilic interaction of urea with backbone of polymer are also contributing in solution properties.
Compounds
#
Formula
Name
1
CH4N2O
urea
2
H2O
water
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.