Abstract
Relation between the molecular structure and the hydrophile lipophile balance (HLB) of nonionic surfactants were investigated using qualitative structure-properties relationship (QSPR) technique. Several descriptors having physical significances on the behaviour of surfactants in portioning between oil and water were selected. Particularly, number of oxygen per a nonionic surfactant molecular weight (chi); octanol/water partition coefficient (log P), maximum surface area (Gamma), molar volume (V-M), dipole moment (mu), energy of hydration (E-H) and molecular polarizability (alpha), parachor (xi), and others Wiener index (W), Randic's molecular connectivity index (R), Kier and Hall valence connectivity index (K & H), average information content (AIC). Principal component analysis (PCA) and multiple linear regression(MLR) technique were performed to examine the relationship between the selected descriptors and the HLB values of nonionic surfactants. The results of PCA explain the inter-relationships between HLB and different variables. The linear relationship between the selected descriptors and HLB was modelled according to the better statistical results. The best model has coefficient of determination (R-2=0.9825), statistical significance (F=1301), and standard errors (s2=1.0521). The obtained a QSPR model allows estimating of HLB for nonionic surfactants using theoretical-calculated descriptors.