Selective Catalytic Oxidation of Benzyl Alcohol by MoO2 Nanoparticles

Transforming Waste Clamshell into Highly Selective Nanostructured Catalysts for Solvent Free Liquid Phase Oxidation of Benzyl Alcohol

High yield production of benzaldehyde in the solvent-free oxidation of benzyl alcohol by using green catalysts is highly desirable. In this work, calcium hydroxide derived from waste clamshell was used as low-cost and environmentally friendly catalyst support (CaSUP) for Pd and V nanoparticles. The physicochemical properties of the catalysts were analyzed using X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) technique, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The catalytic oxidation of benzyl alcohol to benzaldehyde was studied in a liquid phase reaction by using H2O2 as an oxidizing agent. The effects of catalyst loading, the molar ratio of hydrogen peroxide to benzyl alcohol, temperature and reaction duration were investigated. In the optimized conditions, Pd nanoparticles supported on clamshell-derived supports displayed excellent catalytic conversion (88%) and selectivity to benzaldehyde (89%). Furthermore, the catalyst can be effectively reused without a significant loss in its activity and selectivity. The high yield and stability can be related to the structural and basic properties of the catalyst. These results provide important insights into the benzyl alcohol oxidation process for industrial applications.

NiFe2O4 nanoparticles: an efficient and reusable catalyst for the selective oxidation of benzyl alcohol to benzaldehyde under mild conditions

Benzaldehyde is one of the most important and versatile organic chemicals for industrial applications. This study explores a milder approach for the fabrication of NiFe₂O₄ nanoparticles (NPs) for use as a catalyst in the selective oxidation of benzyl alcohol to benzaldehyde. A co-precipitation method coupled with hydrothermal aging has been adopted to synthesize NiFe₂O₄ NPs in the absence of any additive. Different techniques such as electron microscopy, diffractometry, and photoelectron spectroscopy have been used to characterize the products. The results showed that the synthesized NiFe₂O₄ NPs are spherical, pure, and highly crystalline with sizes below 12 nm possessing superparamagnetic behaviour. The catalytic activity of the synthesized NiFe₂O₄ NPs has been assessed in the selective oxidation of benzyl alcohol under ambient reaction conditions. A conversion of 85% benzyl alcohol with 100% selectivity has been attained with t-butyl hydroperoxide at 60 °C in 3 h. With the optimized reaction conditions, the generality of the newly developed protocol has been expanded to a wide array of substituted benzyl alcohols with good performance. The NiFe₂O₄ nanocatalysts are magnetically separable and are reusable up to five cycles without loss of catalytic activity.