Preparation of Fe-BEA zeolites by isomorphous substitution for oxidehydration of glycerol to acrylic acid

• Iron over BEA zeolites increases the glycerol conversion.
• Total conversion of pure glycerol is achieved over 4% Fe BEA zeolite with Si/Al = 50.
• Fe(+ II) species are proposed as main active sites for glycerol conversion.
• Fe(+ III) species are thought to be active sites for acrylic acid formation.

The preparation by post-synthesis isomorphous substitution of FeX-BEA-Y in one step was investigated for the oxidehydration of pure glycerol. TPR and DR UV–vis highlighted the presence of Fe(+ III) species in the framework of zeolites. Iron allows the activation of the catalyst by the reduction by glycerol of part of Fe(+ III) into Fe(+ II) species, which stabilizes the glycerol conversion. Total glycerol conversion is obtained with 4 wt% of iron and acrylic acid yield reaches 23% over this catalyst. The Fe(+ III) tetrahedral species are thought to be the main active redox sites for the formation of acrylic acid.

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