Production of Furan Compounds from Sugarcane Bagasse Using a Catalytic System Containing ZnCl2/HCl or AlCl3/HCl in a Biphasic System

In this work, two catalytic systems combining Lewis and Brønsted acids (ZnCl2/HCl and AlCl3/HCl) were applied in a tetrahydrofuran (THF)/NaClaq biphasic system to produce furan compounds from plant polysaccharides. The following cellulosic matrices were applied for this purpose: α-cellulose, microcrystalline cellulose and both native and steam-exploded sugarcane bagasse. The AlCl3/HCl catalytic system afforded the best yields for α-cellulose conversion to furan compounds (hydrolysis followed by dehydration). The highest yields of 5-(hydroxymethyl)-furfural (HMF) and furfural were 44.0 and 92.2% for AlCl3/HCl and 36.5 and 81.4% for ZnCl2/HCl, respectively. Cellulosic materials with lower crystallinity indexes afforded the best performance in hydrolysis followed by dehydration, giving relatively high yields of HMF and furfural. The HMF yields were similar for both native and steam-exploded sugarcane bagasse and the presence of lignin had a negative effect on HMF production. The highest furfural yield from native sugarcane bagasse was 60.6% with AlCl3/HCl catalytic system.