Brönsted acidic ionic liquid-catalyzed conversion of hemicellulose into sugars

Abstract

Development of a competent method for the conversion of hemicellulose, a lignocellulosic component, into sugars is essential. In a one-pot method, Brönsted acidic ionic liquid (BAIL)-catalyzed hydrolysis of hardwood hemicellulose at 160 °C in water media gave C5 sugars (xylose + arabinose) in 87% yield. The efficiency of the ILs and their acid strength both followed the similar trend, [C₃SO₃HMIM][HSO₄] > [C₃SO₃HMIM][PTS] > [C₃SO₃HMIM][Cl] > [BMIM][Cl]. The ion–dipole-type interaction present between the BAIL and the substrate, which is proposed by the ¹H NMR study, is suggested to help in achieving better activity with BAIL than with mineral acid, H₂SO₄.