Enthalpy of Solvation Correlations for Organic Solutes and Gases Dissolved in 1-Propanol and Tetrahydrofuran Page: 3

                                
1. Introduction

Linear free energy relationship (LFER) models represent a consolidated computational
method to mathematically correlate thermodynamic transfer properties and permeabilities of
chemical compounds to molecular features (called molecular descriptors) that range in type from
topological and structural indices to electronic and quantum-chemical properties. Representative
properties that have been correlated with LFER models include sorption of organic compounds
on polydimethylsiloxane coated fibers [1-3], chromatographic retention times of organic
compounds and drug molecules on immobilized artificial membrane chromatographic columns
[4-6], solute partitioning between water and an immiscible (or partly miscible) organic solvent
[7-10], solute partitioning between two partly miscible organic solvents [11-14], drug
distribution from blood to the various body organs [15-20], permeability of organic compounds
through human skin from aqueous solution [21], brain permeation of neutral molecules and ionic
species [22], and enthalpies of solvation of organic vapors and gases in both water [23] and in
organic solvent media [23-32]. The molecular descriptors may be of either experimental origin
or calculated based solely on molecular structure considerations.
Previously we have applied the Abraham solvation parameter model to correlate
experimental enthalpies of solvation of organic vapors and gases in water, AHsolv,w, [23]:
AHsolv,w (kJ/mol) = -13.310(0.457) + 9.910(0.814) E + 2.836(0.807) S- 32.010(1.102) A
- 41.816(0.781) B - 6.354(0.200) L                                  (1)
(N = 368, SD = 3.68, R2 - 0.964, F = 1950.5)
AHsolv,w (kJ/mol) =-6.952(0.651) + 1.415(0.770) E- 2.859(0.855) S- 34.086(1.225) A
-42.868(0.850) B- 22.720(0.800) V                                   (2)