Nickel Nanoparticles for Liquid Phase Toluene Oxidation – Phenomenon, Opportunities and Challenges

Abstract

Effective oxidative transformation of toluene into valuable products was achieved under solvent-free reaction conditions with as-prepared nickel nanoparticles as heterogeneous catalysts in liquid phase. The crystalline structure and size of the asprepared nanoparticles were confirmed by X-ray diffractometry (XRD) and dynamic light scattering (DLS). The catalytic implications of the different crystalline forms (face-centred cubic: fcc; hexagonal close-packed: hcp) of these nanocatalysts were investigated. The product selectivity of toluene oxidation was found to vary depending on the crystalline forms of the catalyst. Fcc nanocatalysts showed remarkable chemoselectivity (83 mol %) for the product benzyl alcohol and were readily reusable. In contrast, the hcp Ni phase showed reasonable reusability but lower chemoselectivity (29 mol %) compared to its fcc counterpart. Moreover, the simple organic solvents used had a remarkable effect on the crystal structure and phase purity of the Ni nanocrystals, which also affected the catalytic process.

Toluene Oxidation: CO2 vs Benzaldehyde: Current Status and Future Perspectives

“…The liquid phase oxidation of toluene using nickel nanoparticles was tested by Ádám et al, in 2022 . The nickel particles were shown to be crystalline and possess three different crystal phases (hcp, fcc, and fcc+hcp).…”