Pendant drop method combined with axisymmetric drop shape analysis was used to determine liquid-vapor and liquid-liquid interfacial tension of mixtures consisting of heptane(1), toluene(2) and N,N-dimethylformamide(3). The method of pendant drop with an efficient temperature control of the measuring cell allows precision measurements of surface tension and interfacial tension. Surface tensions and liquid densities of more then twenty ternary mixtures in the homogenous region were determined at a normal pressure of 1bar and over a temperature range from 287 K to 317 K. Inside the miscibility gap of this system liquid densities in both liquid phases using buoyancy experiments dependent on temperature were obtained. Furthermore the pendant drop technique allows measurements of the interfacial tension between the two liquid phases even close to the critical solution point for the ternary mixture. The resulting interfacial tension and the density difference versus temperature up to the critical solution point could be well described using a Wegner-type expression.
Compounds
#
Formula
Name
1
C7H16
heptane
2
C7H8
toluene
3
C3H7NO
dimethylformamide
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.