Synthesis and Characterization of Dendrimer-Templated Mesoporous Oxidation Catalysts

Abstract

We report here the use of 4th and 5th generation dendrimers poly(propylene)imine (CU-D32 and CU-D64) as templating agents for the synthesis of mesoporous titanosilicate and vanadosilicate oxidation catalysts via sol-gel techniques. The physical properties of these mesoporous materials were characterized by TGA, BET, PXD and SEM/EDX analyses and these showed that the transition metals are evenly distributed throughout these silicates, which have interconnected spherical pores (approx. 12 Å in diameter) and high surface areas of about 650 m 2 g À1 . Kinetic studies showed that all transition metal-doped catalysts were highly selective at oxidizing cyclohexene to the corresponding epoxide. Additionally, CU-D64-templated catalysts were more catalytically active for cyclohexene epoxidation than CU-D32-templated catalysts as a result of differences in pore size. All CU-D64-templated catalysts exhibited epoxidation catalytic activity comparable to that of titanium doped MCM-41 materials.

Optimization of mesoporous titanosilicate catalysts for cyclohexene epoxidation via statistically guided synthesis

“…2-bottom left). The TOF values indicate that the reaction is reasonably fast, in comparison with other non-functionalized titanosilicates, used under similar conditions, for epoxidation of cyclohexene with TBHP [88][89][90][91]. ICP-AES experiments were conducted on samples 1-7 to evaluate the bulk Ti content in the materials (ESI , Table S2).…”

PAMAM Dendrimer Templated Nanoparticle Catalysts

“…PAMAM and PPI dendrimers can be added to sol -gel silica [ 68 -70] and zinc arsenate [71] syntheses to template mesopores within the oxide material. There are relatively few reports of catalytic applications of these materials, although titanosilicates have been explored as oxidation catalysts [72,73] . In one report, the dendrimer bound Cu 2+ ions were added to sol -gel silica and calcined to yield supported copper oxide nanoparticles.…”

New type of nanofiltration membrane based on crosslinked hyperbranched polymers

“…Dendrimers, which is a kind of special HBPs with perfect branching architecture, has found many possible and important applications in the fields of catalysis, drug delivery, and biomimetics, etc. [21][22][23]. However, dendrimers must be prepared via tedious multi-step synthesis, which limits their applications on a large scale.…”