Preparation and evaluation of some azo-phenol derivatives as antioxidants For egyptian base stock (i)

The oxidation stability of local base stock in the presence of two prepared Azo-compounds, namely 2-sec-butyl-4-((4-methoxyphenyl)-diazenyl) phenol (I) and 2-sec-butyl-4-((4-nitrophenyl)-diazenyl) phenol (II), was studied. The structures of the prepared compounds were carefully investigated via elemental analysis, I.R., 1H-NMR spectroscopy, and electron ionization mass spectroscopy (EI-MS). The oxidation reaction was tested using the change in total acid number (TAN), viscosity, and infra-red (IR) spectroscopy. The data showed that compound (I) is more efficient than compound (II). The quantum chemical parameters such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, energy gap (EHOMO-ELUMO), the dipole moment and charge densities were calculated. The theoretical calculations were in good agreement with experimental results.