Title : Design of Ta-and Nb single site zeolite catalysts for production of 1,3 butadiene from renewable sources
The metal ions well dispersed at zeolite framework are considered to be active sites of catalytic processes. Therefore, the incorporation of these metals into these materials as isolated tetrahedral sites appears to be the important challenge. We have earlier shown that the incorporation of transition metal ions into vacant T-atom sites of framework zeolite is strongly favored when, in the first step, zeolite is dealuminated by treatment with nitric acid solution and then, in the second step, the incorporation of transition metal ions involve a reaction between the cationic metal species of the precursor solution and the SiO-H groups of vacant T-atom sites created by dealumination of zeolite. During my keynote talk the design of new Ta- and Nb-single-site zeolite catalysts will be described and characterized by different physical techniques both at the macroscopic and molecular levels. The application of Ta- and Nb-single-site zeolite catalysts in production of 1,3-butadiene from renewable sources, including ethanol obtained from biomass will be discussed. This two-step postsynthesis method applied in this work allowed obtaining single sites Ta- and Nb-containing zeolite catalysts with mononuclear metal species active in above mentioned cascade reactions. Their catalytic activity strongly depends on the speciation and content of metal incorporated into zeolite structure as well as their acidity.