The Effect of Hydroxyl Groups on Solubilization of Pyridine Derivatives in Span 80–Water–n-Decane Reverse Micelles

Abstract

Computer simulation of pyridine, pyridine-2-ol, and pyridine-2,5-diol solubilization by Span 80–water reverse micelles in n-decane has been performed. All solubilized compounds are polar (their polarity increases in a series pyridine, pyridine-2,5-diol, and pyridine-2-ol) and have different numbers of donors/acceptors forming hydrogen bonds. The most probable positions of pyridine molecules relative to a reverse micelle change fundamentally with a rise in the number of hydroxyl groups in their structure. Pyridine, pyridine-2-ol, and pyridine-2,5-diol are located in the nonpolar medium, on the micelle surface between the head groups of surfactant molecules, and on the inside surface of the aqueous core, respectively. Thus, the number and arrangement of hydrophilic groups in the structure of a molecule, rather than its polarity, have the strongest effect on the ability to solubilization in the reverse micelles.