Direct dehydration of 1,3-butanediol into butadiene over aluminosilicate catalysts

The catalytic dehydration of 1,3-butanediol into butadiene was investigated over various aluminosilicates with different SiO2/Al2O3 ratios and pore architectures. A correlation between the catalytic performance and the total number of acid sites and acid strength was established, with a better performance for lower acid site densities as inferred from combined NH3-TPD, pyridine adsorption and 27Al-NMR MAS spectroscopy. The presence of native Brønsted acid sites of medium strength was correlated to the formation of butadiene. A maximum butadiene yield of 60% was achieved at 300 °C over H-ZSM-5 with a SiO2/Al2O3 ratio of 260 with the simultaneous formation of propylene at a BD/propylene selectivity ratio of 2.5. This catalyst further exhibited a slight deactivation during a 102 h run with a decrease in the conversion from 100% to 80% due to coke deposition as evidenced by XPS and TGA-MS, resulting in a 36% loss of the specific surface area

Kinetic study of products inhibition during glycerol oxidation by Gold supported catalyst. [+ Affiche]

Internationa

«Biomass-derived molecules conversion to chemicals using heterogeneous and homogeneous catalysis»

International audienc

Liquid phase furfural oxidation under uncontrolled pH in batch and flow conditions: The role of in situ formed base

Selective oxidation of furfural to furoic acid was performed with pure oxygen in aqueous phase under mild conditions and uncontrolled pH using hydrotalcite-supported gold nanoparticles as catalyst. Hydrotalcites with different Mg: Al ratios were tested as support. The effects of reaction time, temperature and furfural/catalyst ratio were evaluated. The catalyst Au/HT 4:1 showed the highest activity and selectivity to the desired product, achieving a complete conversion of furfural to furoic acid after 2 h at 110 \ub0C. Further, stability tests were carried out in a continuous stirred-tank reactor and a progressive deactivation of the catalyst due to the leaching of Mg2+ cations from the support inducing changes in the pH of the reaction medium was observed

Al-modified mesoporous silica for efficient conversion of methanol to dimethyl ether

BIOVERT:RAFFINAGE+ATA:PFOThe aim of this work was to design efficient mesoporous heterogeneous catalysts for the reaction of conversion of methanol to dimethyl ether (DME). Mesostructured silica and aluminosilicate solids were synthesized using an original synthesis procedure enabling the elaboration of structurally homogeneous solids at atmospheric pressure and using a food grade templating agent. The prepared solids consisted of mesoporous silica and aluminosilicates with aluminium contents of 0.76, 1.11 and 1.60 wt%. These solids were characterized by XRD, N-2-physisorption and TEM. Their efficiency in the catalytic reaction of conversion of methanol to DME was subsequently correlated with their structural and acidic properties. The sample exhibiting a pore diameter of 2.2 nm for a Si/Al ratio of 27 showed remarkable performances with a methanol conversion as high as 80% at 598 K (7.5 vol% MeOH; 50 mg of catalyst; GHSV = 26,000 cm(3) h(-1) g(-1)) and a total selectivity to DME

Transformation Durable du D-glucose en 5-HMF par Catalyse Hybride : du Réacteur Discontinu au Système à Flux Continu

National audienc