ARTICLE This journal isRuthenium-doped H-Montmorillonite (H-Mont) and Ti-pillared clay (Ti-PILC) were prepared then studied for oxidation of cyclohexene, with tert-butylhydroperoxide (TBHP) as the oxygen source. The Ti-PILC support was prepared by hydrolysis of Ti(OC 3 H 7 ) 4 with HCl. The synthesized Ru/Ti-PILC and Ru/H-Mont catalysts were characterized by chemical analysis, surface area/pore volume measurements, Fourier transform infrared (FTIR) spectroscopy, Xray powder diffraction (XRD), and UV-vis-diffuse reflectance spectroscopy (UV-vis-DRS). Both catalysts can selectively oxidize cyclohexene through allylic oxidation to give 2cyclohexene-1-one as the major product, and 2-cyclohexene-1-ol as the minor product. The influence of reaction time, temperature, catalyst amount, and substrate/oxidant ratio was also investigated to find the optimal reaction for cyclohexene oxidation to get the highest conversion. Indeed, when the 5%Ru/Ti-PILC was employed as catalyst, 59 % of cyclohexene conversion, 87 % of selectivity for 2-cyclohexene-1-one and 13 % of selectivity for 2cyclohexene-1-ol were obtained under ambient pressure, at 70 °C, for a 6 h reaction time. The catalysts were reused in four consecutive runs.

Heterogeneous oxidation of cyclohexane with tertiobutyl hydroperoxide was carried out on Pt/oxide (Al 2 O 3 , TiO 2 and ZrO 2) catalysts in the presence of different solvents (acetic acid and acetonitrile). The catalysts were prepared using Pt(NH 3) 2 (NO 2) 2 as a precursor and characterized by chemical analysis using the ICP-AES method, XRD, TEM, FTIR and BET surface area determination. The oxidation reaction was carried out at 70 • C under atmospheric pressure. The results showed the catalytic performance of Pt/Al 2 O 3 as being very high in terms of turnover frequency.

Mesoporous cobalt oxide was investigated for the liquid phase oxidation of cyclohexene using tertiobutylhydroperoxide (TBHP) as an oxidant. The results were compared with several series of supported cobalt catalysts to study the influence of the cobalt loading and solvents on the overall conversion and selectivity. Mesoporous cobalt was synthesized through the nanocasting route using siliceous SBA-15 mesoporous material as a hard template and cobalt nitrate as the cobalt oxide precursor. Supported cobalt oxide catalysts (Co/MxOy) were synthesized by the impregnation method using two loadings (1 and 5 wt.%) and Al2O3, TiO2, and ZrO2 as supports. Samples were characterised by means: elemental analysis, X-ray powder Diffraction (XRD), BET (surface area), UV-Vis DR Spectroscopy, and Transmission Electron Microscopy (TEM). The results obtained showed that the cobalt oxide retains the mesoporous structure of SBA-15, and in all Co/MxOy, crystalline Co3O4, and CoO phases are observed. The mesoporous cobalt oxide is more active than the supported cobalt catalysts in the allylic oxidation of cyclohexene, with a conversion of 78 % of cyclohexene and 43.3 % selectivity toward 2-cyclohexene-1-ol. The highest activity of mesoporous cobalt oxide could be ascribed to its largest surface area. Furthermore, Co3O4 has both Lewis and Brönsted acidic sites whereas Co/MxOy has only Lewis acidic sites, which could also explain its superior catalytic activity. Moreover, mesoporous cobalt oxide was more stable than supported cobalt catalysts. Therefore, this catalyst is promising for allylic oxidation of alkenes.