Theoretical (density functional theory) studies on the structural, electronic and catalytic properties of the ionic liquid 4-amino-1H-1,2,4-triazolium nitrate

Abstract

Density functional theory calculations using B3LYP/6-311++G(2d,2p) level was used for investigation the geometry, electronic properties and catalytic activity of the ionic liquid 4-amino-1H-1,2,4-triazolium nitrate. Quantum theory of atoms in molecules adequately described the geometry and bonds nature in the title compound. Results revealed that the 4-amino-1H-1,2,4-triazolium nitrate molecule possesses a cyclic structure, stabilized via two hydrogen bonds, C7H8⋯O14 and N9H10⋯O15. The electronic properties and chemical activity of 4-amino-1H-1,2,4-triazolium nitrate were investigated by means of several theoretical approaches, namely molecular electrostatic potential surface, natural bond orbital and frontier molecular orbital analyses. It was established that the oxygen atoms in the structure of nitrate anion characterized the electrophilic reactivity of the obtained ionic liquid. In the light of this, a large electropositive potential was found on the 1,2,4-triazolium ring. The catalytic activity of 4-amino-1H-1,2,4-triazolium nitrate was tested in the reaction of acetic acid esterification with 1-butanol at different reaction temperatures. The obtained experimental data were validated using a pseudo-homogeneous kinetic model.