Catalytic decomposition of isopropanol over chromite spinels MCr2O4(M = Ni, Mn and Mg)

Abstract

The decomposition of isopropanol over nickel, manganese and magnesium chromite spinel catalysts has been investigated in the vapour phase in an integral reactor. Its decomposition follows first-order kinetics. Kinetic and thermodynamic parameters have been calculated using the Arrhenius and Eyring equations. The activity pattern is found to be NiCr₂O₄ > MnCr₂O₄ > MgCr₂O₄. The chromite spinels have been characterised by X-ray studies, i.r. spectral analysis, conductivity and thermoelectric potential measurements. All three chromites were found to be p-type semiconductors in the temperature range 150–400 °C. Exclusive dehydrogenation is shown by NiCr₂O₄ and MnCr₂O₄, whereas MgCr₂O₄ functions as a dehydrogenation and dehydration catalyst. A linear correlation exists between the entropy of activation and the activation energy for electrical conduction for the chromite spinels studied.