Hydrothermolysis of carbohydrates to levulinic acid using metal supported on porous aluminosilicate

BACKGROUNDAluminosilicate catalysts have the potential to promote the formation of oxygenated derivatives from carbohydrates in a hydrothermolysis reaction. Levulinic acid (LA) can be obtained from glucose, sucrose and starch hydrothermolysis reactions, and is a very versatile building block for diverse organic synthetic compounds. In this work, the catalytic performance of Ni- or Ru-doped aluminum-loaded SBA-15 (Al-SBA-15) was compared with ZSM-5 catalyst in order to achieve high LA selectivity. RESULTSAll catalytic hydrothermolysis reactions tested gave remarkably higher LA selectivity than non-catalytic reactions for every carbohydrate substrate used. The acid contents and porous properties are important keys to control yield and selectivity of LA. The highest selectivity of LA (44%) was attained from glucose hydrothermolysis at 200 degrees C (for 1h) using a 15wt% loading of the 20wt% Ru-doped ZSM-5 catalyst. CONCLUSIONModerately raising Ru in ZSM-5 and Al-SBA-15 catalysts increased the levels of LA. The MFI structure of ZSM-5 is suitable for hydrothermolysis of glucose monosaccharide, while the hexagonal mesoporous structure of Al-SBA-15 is preferred for starch polysaccharide hydrothermolysis at the optimum condition. (c) 2012 Society of Chemical Industry