Magnetic N-doped Mesoporous Carbon Sheet: A Reusable and Heterogeneous Catalyst for Promoting Oxidation Reaction

Selective oxidation remains a significant matter for research. This is due to the importance of selective oxidation as a unitprocess in the manufacture of chemical intermediates. The oxidation of alcohols to the corresponding carbonyl compounds is a fundamentallyimportant transformation in synthetic organic chemistry. Among, conversion of benzyl alcohol to benzoic acid is very important because itserved as an intermediate in the biosynthesis of many secondary metabolites. Along this compound is a suitable precursor for a number of finechemicals and the currently industrial method to prepare benzoic acid. Many selective oxidation reactions are carried out without the use ofmodern catalytic technology and in such cases these oxidations are effected using stoichiometric oxygen donors, such as chromate orpermanganate. However, such reagents are expensive and have serious toxicity issues associated with them. To date, many studies have beenreported on the oxidation of benzyl alcohol using novel homogeneous and heterogeneous catalysts under different conditions. In particular,aerobic condition is considered a green process because O2 is readily available and the alcohol can be used directly in the reactor withoutadditives. Moreover, reported homogeneous catalysts mostly displayed a considerable initial loss in activity and poor-recycling ability. Porouscarbon materials have attracted considerable attention due to their applications in a wide range of areas, including energy storage andconversion, adsorption, catalysis, sensor technology, controlled drug release and cellular delivery. As an important class of novel porouscarbons, N-doped mesoporous carbon materials have become a research hotspot due to their unique morphology, large surface area and porevolume, good electrical conductivity, and high physical and chemical stability. In recent years, with the rapid growth in the preparation andapplications of N-doped mesoporous carbon, these materials present great utilitarian value for catalysis. Recently we designed and preparedseveral heterogeneous catalysts and proving their utility for development for various chemical transformations under green conditions. In thefollowing of our interest in the development of heterogeneous catalysts, recently, we have focused our research on Carbon-based catalysts. Inthis line, we reported the outstanding effect of composition of magnetic nanoparticles with N-doped mesoporous carbon materials, on thecatalytic activity and recyclability of the heterogeneous catalysts. Encouraged by those promising results, herein we design a novel magneticmesoporous system, composed of hollow-Fe2O3 nanoparticles and N-doped mesoporous carbon sheet. The resulting catalytic system, h-Fe2O3@NPC, was applied for promoting the oxidation of benzyl alcohol under aerobic condition. Precise study was carried out to investigatethe contribution of magnetic system to the recyclability of the catalyst. Moreover, the role of N-rich carbon sheet and in the catalysis and theeffect of using it N-free carbon materials on the catalytic activity were scrutinized. Moreover, it was proved that incorporation of NPC wasmore effective than graphitic carbon nitride and grapheme oxide. Furthermore, the catalytic recyclability of h-Fe2O3@NPC was examined. Thecatalyst could be successfully removed from the reaction mixture by using an external magnet and also recycled for several consecutivereaction times with slight loss of the catalytic activity.

کلیدواژه ها:

Heterogeneous Catalyst ، N-doped Carbon ، Oxidation Reaction ، Aerobic condition