ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Reaction of aniline with ammonium persulphate and concentrated hydrochloric acid: Experimental and DFT studies

Maciej Przybyłek and Jerzy Gaca

Department of Chemistry and Environmental Protection, Faculty of Chemical Technology and Engineering, University of Technology and Life Sciences, 85-326 Bydgoszcz, Poland

E-mail: przybylek@mail.utp.edu.pl

Abstract: In this paper, the reaction of aniline with ammonium persulphate and concentrated HCl was studied. As a result of our experimental studies, 2,4,6-trichlorophenylamine was identified as the main product. This shows that a high concentration of HCl does not favour oxidative polymerisation of phenylamine, even though the ammonium persulphate/HCl system is widely used in polyaniline synthesis. On the basis of the experimental data and density functional theory for reaction path modelling, we proposed a mechanism for oxidative chlorination of aniline. We assumed that this reaction proceeded in three cyclically repeated steps; protonation of aniline, formation of singlet ground state phenylnitrenium cation, and nucleophilic substitution. In order to confirm this mechanism, kinetic, thermochemical, and natural bond orbital population analyses were performed.

Keywords: oxidative chlorination – 2,4,6-trichloroaniline – DFT

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-012-0163-1

Chemical Papers 66 (7) 699–708 (2012)