TiO2-supported molybdenum carbide: An active catalyst for the aqueous phase hydrogenation of succinic acid

Tio(2)-supported Mo carbides "MoC/TiO2" were prepared by impregnation of Mo salt followed by temperature programmed reduction-carburization using 20% v/v C2H6/H-2. Catalysts were characterized by XRD, XPS, TEM, STEM, 1CP, Raman, BET, and carbon elemental analysis. The catalytic activity was evaluated for aqueous phase hydrogenation of succinic acid at 160-240 degrees C, and 90-150 bar of H-2 in batch reactor. MoC/TiO2 is active for this reaction. The main products after 24 h are gamma-butyrolactone, and more remarkably butyric acid. These intermediates are then converted to tetrahydrofuran, butanol, 1,4-butanediol and butane. The reaction conditions (temperature, pressure) do not impact the products distribution. A larger amount of butyric acid is formed when catalysts were synthesized with a higher gas hourly space velocity. The deactivation observed while recycling the catalyst was mainly attributed to a decrease in the amounts of carbidic molybdenum and carbidic carbon, as demonstrated by XPS analysis.