Zeolites with Br�nsted acidity are promising catalysts for aqueous phase hydrodeoxygenation of phenolic oils derived from biomass. Better understanding of both the behavior of zeolite active sites and framework structural integrity in hot liquid water is critically needed to improve catalyst lifetime and activity. An in-depth study of the effects of hot liquid water on HBEA zeolites was performed using X-ray absorption spectroscopy combined with ab initio computations that enabled quantitative analysis of the spectral data. The EXAFS measurements allowed monitoring of the changes in geometries of the aluminum tetrahedral sites accompanying treatment. The HBEA samples differed markedly in Al distribution and in framework stability in hot liquid water. Only subtle structural modifications of the active sites were observed at 160 �C, which is suitable for catalytic reactions, e.g. cyclohexanol dehydration. At temperatures as high as 300 �C complete framework degradation is observed. Unlike during zeolite steam treatment, removal of framework Al (dealumination) is not observed in aqueous environment prior to lattice disintegration.

Development and application of Al EXAFS to characterize Al T-sites in zeolite: Effect of hot liquid water treatment on the HBEA zeolite framework

248th National Meeting (2014)

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