A Revisited Definition of the Three Solute Descriptors Related to the Van der Waals Forces in Solutions

Abstract

It is currently admitted that the intermolecular forces implicated in Gas Liquid Chromatography (GLC) can be expressed as a product of parameters (or descriptors) of solutes and of parameters of solvents. The present study is limited to those of solutes, and among them the three ones are involved in the Van der Waals forces, whereas the two ones involved in the hydrogen bonding are left aside at this stage. These three studied parameters, which we call δ, ω and ε, respectively reflect the three types of Van der Waals forces: dispersion, orientation or polarity strictly speaking, and induction-polarizability. These parameters have been experimentally obtained in previous studies for 121 Volatile Organic Compounds (VOC) via an original Multiplicative Matrix Analysis (MMA) applied to a superabundant and accurate GLC data set. Then, also in previous studies, attempts have been made to predict these parameters via a Simplified Molecular Topology procedure (SMT). Because these last published results have been somewhat disappointing, a promising new strategy of prediction is developed and detailed in the present article.

Updated Definition of the Three Solvent Descriptors Related to the Van der Waals Forces in Solutions

“…As already seen in the Introduction, the present study is similar to our 2016 study for solutes, of descriptors prediction for solvents using the SMT procedure [4]. The principal observation in this last publication for solutes, was that in order to mitigate previous disappointing published results, the optimal approach was to limit those experimental descriptors to very accurate ones, more precisely those derived from a matrix of 127 solutes × 11 phases established by the Kováts group, using an original algorithm presently called MMA (as Multiplicative Matrix Analysis) [6] [13].…”

“…We have recently published a revisited definition, on experimental basis, of the three solute parameters or descriptors δ, ω and β, related to the Van der Waals forces in solutions, as they are involved in GLC [4]. The present study reflects a similar attempt for the solvent descriptors D, W and E. The comparison with previous results on this topic will be stated in the Discussion and Perspectives section.…”

“…The On the other hand and more generally speaking as already underlined [4], all the studies based on the so called Abraham molecular descriptors are difficult to be compared with those based on mutually independent solute descriptors, as we are proposing since 2005 [13].…”

Optimization of Ultrasound-Assisted Cellulase Extraction from Nymphaea hybrid Flower and Biological Activities: Antioxidant Activity, Protective Effect against ROS Oxidative Damage in HaCaT Cells and Inhibition of Melanin Production in B16 Cells

“…The solutions of NHE were adjusted to a different pH value (2.0, 3.0, 4.0, 5.0 and 6.0) by using 2.0 mol/L HCl and 2.0 mol/L NaOH solutions. Because flavonoids have a phenolic hydroxyl structure and are acidic, they can exist in a molecular state and can be absorbed into the resin by van der Waals force under the condition of the weak acid [ 44 ]. Therefore, the flavonoid content was highest at pH = 3.…”