Application of carbonized cellulose-based catalyst in nitrobenzene hydrogenation. (September 2020) - Prekob, Á.
Abstract: Carbonized cellulose catalyst support was prepared and decorated with 5 wt% Pd nanoparticles using an impregnation method. According to the SEM images, the carbonized cellulose catalyst support kept its original fibrous structure with an average diameter of 200 nm, owing to the carbonization of the cellulose fibers. The surface of the formed carbon fibers is richly coated by palladium with even coverage. The particles can be divided into two groups within which the average diameter is either 5 nm, or 20–70 nm. TGA method was used to measure the amount of the remained carbon, which was 31.71 wt%. The FTIR spectrum shows the presence of oxygen containing functional groups on the surface of the support, which are hydroxyl groups. XRD method was used to determine the phases of Pd on the support where elemental Pd was detected which confirms the success of the activation step. The catalyst was tested in nitrobenzene hydrogenation in methanolic solution as a model reaction for nitroarene hydrogenation, meanwhile the temperature dependence of the reaction was also examined. Catalytic tests were carried out at four different temperatures (283–323 K) and constant hydrogen pressure (20 bar). The highest conversion (>99%) has been reached at 303 K and 20 bar. The corresponding activation energy was calculated by non-linear regression based on Arrhenius plot, and it was 24.16 ± 0.8 kJ/mol. All in all, the granulated cellulose beads are ideal starting points for carbon based catalyst supports. Highlights: Easily prepared, alternative cellulose based support for sustainable catalyst preparation. Fibrous structure for accelerated mass transport. Relatively low (24.16 ± 0.8 kJ/mol) activation energy. High nitrobenzene conversion value (̴ 100%) with only one by-product.