Molybdenum Carbonyl Funcionalized Hafnium-UiO-66 For Heterogeneous Catalytic Olefin Epoxidation
authors Diana M. Gomes, Andreia Silva, Ana C. Gomes, Patrícia Neves, Martyn Pillinger, Anabela A. Valente, Isabel S. Gonçalves
nationality International
abstract The epoxidation of olefins gives epoxides, which is of great interest to different industrial sectors. This study deals with new heterogeneous epoxidation catalysts based on molybdenum-functionalized Hf-containing UiO-66 metal-organic frameworks (Mo/Hf-UiO-66). The materials were synthesized in a stepwise fashion, and characterized by complementary techniques, including PXRD, SEM, EDS, elemental analysis, FT-IR spectroscopy. The zirconium-containing counterpart (Mo/Zr-UiO-66) was prepared for comparative studies. The Mo/UiO-66 based materials were efficient heterogeneous catalysts for olefin epoxidation, based on the model reaction of cis-cyclooctene with tert-butyl hydroperoxide (TBHP) as oxidant, at 70 ºC. The type of support and the conditions used in the post-synthesis functionalization with molybdenum influenced the catalytic results. The material Mo(8.8)/Hf-MOF (5) was best-performing in terms of catalytic activity and stability, in relation to the Mo/Zr-UiO-66 counterpart. The favorable effects of the crystalline support Hf-UiO-66 over the Zr-UiO-66 one for the heterogenization of molybdenum complexes for heterogeneous catalytic olefin epoxidation, are highlighted.
year published 2020