화학공학소재연구정보센터
Fuel, Vol.228, 175-186, 2018
Upgrading of pyrolysis biofuel via esterification of acetic acid with benzyl alcohol catalyzed by Bronsted acidic ionic liquid functionalized ethyl-bridged organosilica hollow nanospheres
Catalytic esterification of acetic acid with high boiling point benzyl alcohol is a primary goal to decrease oxygen content and acidity of crude pyrolysis biofuels before their further refining steps; meanwhile, the produced benzyl acetate is a value-added chemical building. In the search for efficient and recyclable solid acids for the above process, Bronsted acidic ionic liquid functionalized ethyl-bridged organosilica hollow nanospheres, [C(3)Im][SO3CF3]-Si(Et) Si HNSs (C-3 = PrSO3H, Im = imidazolium cation), are demonstrated via co-condensation route followed by quaternary ammonization and anion exchange. The [C(3)Im][SO3CF3]-Si(Et) Si HNSs with nanometer size, hollow interior, opening and permeable thin shell as well as large BET surface area are successfully applied in esterification of acetic acid with benzyl alcohol in toluene as a simulated pyrolysis biofuel, and influence of reaction temperature, benzyl alcohol-to-acetic acid molar ratio and water content on the catalytic activity and selectivity are evaluated. The [C(3)Im][SO3CF3]-Si(Et) Si HNSs exhibit significantly high catalytic activity and selectivity in target reaction, outperforming Amberlyst-15 resin and HY zeolite; moreover, morphological characteristics, textural properties and surface hydrophobicity impact the esterification activity. The [C(3)Im][SO3CF3]-Si(Et) Si HNSs also exhibit good catalytic stability and reusability, and leaching of acid sites as well as changes of chemical structure and morphology of the nanohybrids are hardly observed after the reaction.