Palladated cyclodextrin and halloysite containing polymer and its carbonized form as efficient hydrogenation catalysts

Abstract

β-Cyclodextrin (β-CD) and glycidyl methacrylate monomer were polymerized in the presence of functionalized halloysite nanoclay (Hal) to afford a polymeric network (Hal-P-CD) containing Hal and CD. Hal-P-CD was then applied as a catalyst support for the immobilization of Pd nanoparticles. The resulting nanocomposite, Pd@Hal-P-CD, could serve as a catalyst for the hydrogenation of nitrobenzene. The precise study by the preparation of control samples confirmed the contribution of CD as both phase transfer and capping agent, P (polymer) and Hal to the catalysis. Moreover, the results confirmed the importance of CD: glycidyl methacrylate monomer ratio. Pd@Hal-P-CD was also carbonized to prepare Pd@Hal-C. Notably, the characterization of Pd@Hal-C showed that carbonization led to the growth of mean diameter of Pd nanoparticles, increase of Pd content and partial destruction of Hal. However, the catalytic activity of Pd@Hal-C was superior to Pd@Hal-P-CD. Pd@Hal-C was also highly recyclable and could be recovered and recycled for several reaction runs.The study of the carbonization temperature showed that this factor affected the nature of the resulting carbon and the catalyst prepared at elevated temperature showed higher catalytic activity.

Direct conversion of glucose to 5-hydroxymethylfurfural over niobium oxide/phosphate-carbon composites derived from hydrothermal carbonization of cyclodextrins

“…Although the potential of cyclodextrins has been the subject of several investigations for the synthesis of pure carbon nanostructures [42][43][44][45][46][47][48], the number of reports on the synthesis and properties of metal-carbon composites is still limited, especially by hydrothermal carbonization. Indeed, most of the work has focused on pyrolysis methods with mixtures of cyclodextrins and metal precursors (assisted or not by additional organic [49] or inorganic [50] structure-directing agents) and on templating techniques using inorganic sacrificial materials [51,52]. Yet, hydrothermal carbonization (HTC) of high carbon-content materials (i.e.…”