Gibbs Energy and Helmholtz Energy: Liquids, Solutions and Vapours
CHAPTER 11: Limiting Activity Coefficients: New Procedures, Computations and Measurements
Published:08 Sep 2021
J. David Raal and S. A. Iwarere, in Gibbs Energy and Helmholtz Energy: Liquids, Solutions and Vapours, ed. E. Wilhelm and T. M. Letcher, The Royal Society of Chemistry, 2021, pp. 345-362.
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New developments in differential ebulliometry include improved rigour in a new method for calculating the liquid equilibrium composition from the charge composition and calculation of entropy generation quantities such as total entropy generation and the contributions from fluid friction and irreversible heat transfer, in the Cottrell pump, by a novel iterative procedure. For gas or gas–liquid mixtures, measurement problems in the dilute regions (particularly) include accurate preparation of mixtures, down to ppm levels, for gas chromatograph detector calibration. A novel automated static mixing technology can accurately produce mixtures sufficiently dilute to challenge detector capabilities while also producing second virial coefficients. Impellor rotation with a fail-safe start rapidly produces homogeneous mixtures. Introducing a weighed amount of pure or impure liquid produces detector response factors and, from the pressure rise, the impurity concentration. The solution of equation sets by a novel iterative procedure permits the use of impure gases and produces both the impurity concentrations and the response factor ratios, a long-sought goal.