Bentonite is an abundant natural resource in the Maghnia region of Algeria that may have potential value in catalysis, but heretofore has been considered of low value for this purpose due to its low acidity and low catalytic activity. Low cost is one of the main criteria for choosing a suitable material for catalysis. Because bentonite is abundant and low-cost, its use as a starting material for the preparation of catalysts deserves reconsideration. The present study was undertaken, therefore, to optimize the performance of bentonite as a catalyst in one of the most promising reactions in organic synthesis, namely, cyclohexene epoxidation. The bentonite was subjected to adjustment of its structure by means of a number of laboratory treatments based on its large cation exchange capacity. These modifications aimed to achieve an environmentally friendly catalytic process by incorporating transition metals, specifically titanium and vanadium, into the modified bentonite structure through acid activation. Redox properties were enhanced and Lewis and Brønsted acidities were introduced. The vanadium oxide, supported on titania-pillared, acid-activated bentonite (5V/Ti-AAC), was characterized comprehensively using various techniques, including diffuse-reflectance UV-visible spectroscopy (DR UV-Vis), Fourier-transform infrared spectroscopy (FTIR) for surface acidity analysis, X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray elemental analysis (EDX). The catalytic activity was investigated in response to certain variables, such as catalyst mass, nature of the solvent, amount of oxidant, and reaction temperature. A kinetic study was conducted to understand the reaction behavior. The experimental results demonstrated intriguing catalytic activity, achieving a 42% conversion rate with ~68% selectivity toward the epoxide product when employing tert-butyl hydroperoxide (TBHP) as the oxidant and heptane as the solvent. This study highlights the potential of 5V/Ti-AAC as an environmentally friendly catalyst applied in the epoxidation of cyclohexene.

Mesoporous molecular sieves MCM-41 modified by single (Ti) and bimetal (Ti-V) ions with highly ordered hexagonal arrangement of their cylindrical channels were prepared by direct synthesis under microwave–hydrothermal (M–H) conditions at 403K. Characterizations with powder X-ray diffraction (XRD), 29Si magic-angle spinning (MAS) NMR, N2 adsorption–desorption, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelcctron spectra(XPS) and transmission electron microscopy (TEM) showed that Ti and V ions were introduced into MCM-41 under M-H conditions and Ti/V-Si bond was formed. Results revealed that all the samples were of a typical hexagonal arrangement of mesoporous structure. The modified materials were high active and selective in the epoxidation of styrene at 343 K in comparison with single-functional MCM-41. Moreover, compared to conventional method, the presented microwave hydrothermal synthesis of molecular sieves greatly improved the selectivity to styrene oxide, e.g., it reached 58.6% at styrene conversion of 18.7% over Ti-V-MCM-41 (50).