Estimates of the Properties of Liquids

Abstract

An equation which relates the volume term ( V = M / (~L -p g ) ) of unassociated liquids to pressure P and temperature T has been obtained by the combination of (a) 0 . 3 V ( a l / a V )~, , = T,-T for the effect of temperature on V at low (atmospheric) pressure and (b) -V(aP/a V ) T = P, Vx6/ V"P+O + 9( P -p ) for the effect of pressure on volume at constant temperature. In the equations, p is the vapour pressure; p~ the density of the liquid and pe the vapour density. Often pg can be neglected compared with PL a n d p is small compared with the large pressures required to affect the densities of liquids appreciably. There are three constants: T,, P,, which equals 4.455 x 10" N m-2, and V, which can be calculated by rhe addition of atomic values for all the atoms in the molecule and subtraction of a value (6.56 x m3 mol-1) for each bond. When V approximates to Ilt/pL, the molar volume, the equation can be integrated to give the work and heat of isothermal compression. The viscosity of a liquid is related to the work of compression and solubilities in a liquid to the work required to bring the solute to the compressibility of the liquid. Many relationships can be derived and can be used to estimate properties of unassociated liquids.

Transport properties of the mung bean (Vigna radiata ) non-aerial hypocotyl membrane: permselectivity to hydrophilic compounds

“…where V x is the molar volume of the diffusing molecule calculated according to McGowan and N is Avogadro's number. Average radii for PEG 200, PEG 400, PEG 600 and PEG 1000 were calculated in the present study to be 0.41 nm, 0.50 nm, 0.58 nm and 0.68 nm, respectively.…”

What Determines CO2 Solubility in Ionic Liquids? A Molecular Simulation Study

“…The volume of a CO 2 molecule can be estimated with the McGowan method (this simple method is outlined in section 3.5) to be roughly 27.7 cm 3 /mol. 64 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 NTf 2 for instance exhibited the largest value of r unocc , which translates to an area of unoccupied space of 198 cm 3 /mol that is available for each CO 2 molecule at saturation concentration. This means that ample of empty space would be available to accommodate all CO 2 .molecules.…”

“…The size of an ion pair can be approximated with the simple McGowan method, in which for each atom in the ion pair an element-specific volume is added and from which a constant volume is subtracted for each present covalent bond. 64 The McGowan volumes of all ion pairs considered in simulations are listed in Table 7. These McGowan volumes were converted into McGowan ion densities, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 which are yielded with the approximation that the entire IL volume is filled with ion pairs of their respective McGowan volumes.…”

Nicotine aqueous solutions: pH-measurements and salting-out effects - analysis of the effective Gibbs energies of hydration and ionic strengths of the solutions

“…6 TABLE II Salt: The values of the molar Gibbs energies of hydration of each ion species i at 298.15 K and 0.1 MPa, (G i ) hyd , both for the solutions studied herein and previously, 6 are presented in Table III. Thus, the radius was calculated either i) using the radius for 2 4 SO − (0.230 nm) 31 and the contributions for the CH 3 -and CH 2 -groups given by Bondi 32 or ii) by applying the procedure based on the McGowan volumes, 33 given by Zhao et al 34 -see the Supplementary Material to this paper for details. 29 The radii for [C 2 mim] + (0.303 nm) 30 and 2 4 HPO − (0.238 nm) 31 were taken from the literature.…”