Ba-modified ordered mesoporous SBA-15 for selective dehydration of lactic acid to acrylic acid

Conversion of biomass-derived lactic acid (LA) to acrylic acid (AA) through a gas-phase dehydration was studied using mesoporous Ba-supported SBA-15 catalysts with different Ba content. These catalysts were prepared by dry impregnation method with barium hydroxide octahydrate as a precursor. The Ba(17)/SBA-15 catalyst, containing highly dispersed surface bidentate barium carbonates phases at an optimal Ba content of 17 wt%, exhibited a larger amount of active Lewis acid sites and weak basic sites, which resulted in significantly enhanced LA conversion of 94.7 % and high AA selectivity of 87.6 %, which was found to be the best yield of the product ever reported. Moreover, the Ba(17)/SBA-15 catalyst demonstrated a stable catalytic activity over 100 h reaction duration. The improved stability was attributed to the formation of stable crucial surface intermediates such as barium lactate on the well-dispersed active barium carbonates in the highly ordered mesoporous SBA-15 structures, which was confirmed by in situ-FT-IR analysis and surface acidic and basic sites measurements.