Partitioning of structurally related thiophene derivatives between solvent and micellar media of anionic surfactant sodium dodecyl sulphate

The present study describes the detailed investigations of the solubilization of thiophene derivatives i.e. 5-(2-(benzyloxy) phenyl) thiophene-2-sulfonamide (BPTS) and 5-bromothiophene-2-sulfonamide (BTS) by micellar solution of anionic surfactant, Sodium dodecyl sulphate (SDS). The interaction of SDS in the solution containing aforementioned compounds was investigated by electrical conductivity and UV vis spectroscopy. The data of electrical conductivity was used to calculate thermodynamic parameters like free energy (Delta G(m)), enthalpy (Delta H-m) and entropy (Delta S-m) of micellization of SDS in the presence of thiophenes, whereas UV vis spectroscopy was used to calculate the extent of solubilization in term of partition coefficient (K-x), free energy of partition (Delta G(p)), binding constant (K-b) and free energy of binding (Delta G(b)). The experimental results from thermodynamic parameters reveal that the solubilization of said thiophene derivatives was spontaneous, in addition to enthalpy and entropy driven. The large molecular size, aromatic nature with extensive delocalization and less charge density of BPTS was found to have a negative impact on solubilization of this compound, which was observed from poor binding capacity and inadequate partitioning displayed by this compound. (C) 2016 Elsevier B.V. All rights reserved.