Effect of stearates on the thermal oxidation process of paraffin

Abstract

Thermal reaction process of paraffin/stearate mixtures was studied by thermogravimetric–differential scanning calorimetry–Fourier transform infrared spectroscopy (TG–DSC–FTIR) simultaneous experiments under argon and oxygen atmospheres, and the thermal reaction kinetics were estimated through the non-isothermal measurements and model-free isoconversional methods. The results show that all stearates except for magnesium stearate have a positive effect on the oxidation of paraffin at lower temperature, but only cobalt stearate plays a positive effect during the whole oxidation process; the oxidation of paraffin/cobalt stearate mixture could be divided into three stages, and cobalt stearate could decrease the oxidation reaction temperature of paraffin obviously concerning the first stage; however, the catalytic effects could not be improved markedly by adding more cobalt stearate; the increase in activation energy (Ea) with the increase of cobalt stearate may be attributed to the adsorption catalysis system of the oxidation process.