Hydrodeoxygenation of Isoeugenol over Ni- and Co-Supported Catalysts

Hydrodeoxygenation (HDO) of isoeugenol was investigated over several Ni (Ni/SiO2, Ni/graphite) and Co (Co/SBA-15, Co/SiO2, Co/TiO2, Co/Al2O3) catalysts at 200 and 300 degrees C under 30 bar hydrogen pressure in a batch reactor. The catalysts were prepared by an impregnation method and systematically characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and energy dispersive analysis, organic elemental, and thermogravimetrical analysis before and after the reaction. Analysis of the liquid, solid, and gaseous products was performed to identify isoeugenol transformation pathways. The maximum yield of the desired propylcyclohexane (PCH) (63%) and the highest sum of masses of reactants and products in the liquid phase based on GC results (GCLPA) (79%) were obtained over 10 wt % Co/SBA-15. HDO of isoeugenol over 11 wt % Co/SiO2 resulted in 50% PCH yield with a rather similar GCLPA of 73%. Low yields of PCH and the liquid phase mass balance closure were obtained over highly dispersed 15 wt % Co/Al2O3 and 15 wt % Co/TiO2. PCH yield was 60% over Ni/graphite and 44% over Ni/SiO2 after 4 h with GCLPA values of 73 and 70%, correspondingly. Overall PCH yields increased in the following order: Co/TiO2 < Co/Al2O3 < Ni/SiO2 < Co/SiO2 < Ni/graphite < Co/SBA-15. Regeneration and reuse of industrially relevant 11 wt % Co/SiO2 was succesfully demonstrated

Hydrodeoxygenation of Isoeugenol over Alumina-Supported Ir, Pt, and Re Catalysts

Hydrodeoxygenation (HDO) of isoeugenol (IE) was investigated using bimetallic iridium rhenium and platinum rhenium catalysts supported on alumina in the temperature and pressure ranges of 200-250 degrees C and 17-40 bar in nonpolar dodecane as a solvent. The main parameters were catalyst type, hydrogen pressure, and initial concentration. Nearly quantitative yield of the desired product, propylcyclohexane (PCH), at complete conversion in 240 min was obtained with Ir-Re/Al2O3 prepared by the deposition-precipitation method using 0.1 mol/L IE initial concentration. High iridium dispersion together with a modification effect of rhenium provided in situ formation of the IrRe active component with reproducible catalytic activity for selective HDO of IE to PCH. The reaction rate was shown to increase with the increasing initial IE concentration promoting also HDO and giving a higher liquid phase mass balance. Increasing hydrogen pressure benefits the PCH yield