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Fe-MFI zeolites are very promising materials for the oxidehydration of glycerol. This work shows that preparation procedure influences product selectivity. Hydrothermal synthesis is more selective to acrylic acid thanks to the Fe(+III) tetrahedral species in framework position. Conversely, post-synthesis treatment in a fluoride medium generates Fe(+II) Ox clusters in extra-framework position that increases acrolein selectivity. The reduction of the crystalline size of iron MFI to a nanoscale leads to a highly active, selective and stable catalyst with a stabilized glycerol (40 wt% in water) conversion of 90% and acrolein selectivity of 87%.

SSCI-VIDE+CDFA+NPR:CPI:MBE; International audience; 1,6-Hexanediol is an emerging building-block chemical, which may be derived from biomass and can produce adipic acid for the synthesis of polymers. A series of supported Pt, Bi-Pt, Au, Pd, Au-Pd, and Au-Pt catalysts were prepared and evaluated in the aerobic oxidation of 1,6-hexanediol to adipic acid in aqueous solution without the addition of a base or an acid. The influences of various molar ratios of the metals in the bimetallic systems and the support (C, ZrO2) were studied. Under the conditions used, bismuth did not promote the catalytic performance of Pt catalysts. On the other hand, formation of an alloy of Au-Pd or Au-Pt made the catalysts very effective. A yield of adipic acid of ca. 96% was achieved at 70 °C under 40 bar of air over the Au-Pt catalyst supported on zirconia with a Au/Pt molar ratio of about 1. Recycling tests revealed the possibility to use the catalyst up to 6 times without significant changes in its catalytic performance.

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