Theoretical and Experimental Study of the Process for Obtaining PAni(DBSA) - Part I: Formation of the Anilinium-DBS Salt

The first step in the synthesis of polyaniline doped with dodecylbenzene sulfonic acid is the synthesis of the anilinium dodecylbenzene sulfonate salt obtained through the reaction between aniline and dodecylbenzene sulfonic acid in aqueous medium. In this work, theoretical models were developed to simulate the formation mechanism of this salt in an aqueous medium. Changes in energy, frontier orbitals, gap energy, charge distribution and thermodynamic parameters were calculated. These theoretical results were correlated with the experimental data from the synthesis of the salt and from infrared spectroscopy. Theoretical models suggested that the solubilization of dodecylbenzene sulfonic acid and aniline in water are energetically and thermodynamically favorable processes. Interactions between the frontier orbitals indicated the formation of water-insoluble anilinium dodecylbenzene sulfonate salt. These molecular modeling results agree with experimental data indicating that the theoretical method used was efficient in simulating the reaction system.