Evaluation of Polar Order of Common Solvents from Fraction of Positive Charge in Molecules
从分子中正电荷分数探讨常用溶剂的极性顺序

Based on the satistical tests to group electronegativity values reported in references the most probable values of group electronegativity were calculated. Then, the fraction of positive charges in a molecule of some common solvents was calculated, based upon Sanderson's equilibration principle on electronegativity.The fraction of positive charges can represent the polar order of common solvents which is corresponding in general to those actual measurements by Trappe, Strain, Jacques et al and is equivalent approximately to Snyder's eluotropic series of solvents obtained from experiments. If the fraction of positive charges in a molecule increases, not only the polarity of solvents but also the solvent elution strength will increase. The polarity of homologue described with the fraction of positive charges conforms in general to molecular structure.However, the fraction of positive charges in a molecule obtained by calculations can only represent the property of the single substance and the quantity of the polarity of pure solvent. The effect of stationary phase and experiment conditions was not considered. Generally, the method to obtain the order of the polarity of solvents with calculation of the fraction of positive charges in a molecule by electronegativity is more predictive and more universal than those methods of measurement.