Aryl sulfonic acid catalyzed hydrolysis of cellulose in water

Catalytic activities of eight alkyl/aryl sulfonic acids in water were compared with sulfuric acid of the same acid strength (0.0321 mol H+ ion/L) for hydrolysis of Sigmacell cellulose (DP ∼ 450) in the 140–190 °C temperature range by measuring total reducing sugar (TRS), and glucose produced. Cellulose samples hydrolyzed at 160 °C for 3 h, in aqueous p-toluenesulfonic acid, 2-naphthalenesulfonic acid, and 4-biphenylsulfonic acid mediums produced TRS yields of 28.0, 25.4, and 30.3% respectively, when compared to 21.7% TRS produced in aqueous sulfuric acid medium. The first order rate constants at 160 °C in different acid mediums correlated with octanol/water distribution coefficient log D of these acids, except in the case of highly hydrophobic 4-dodceylbenzenesulfonic acid. In the series of sulfonic acids studied, 4-biphenylsulfonic acid appears to be the best cellulose hydrolysis catalyst.

Figure optionsDownload high-quality image (92 K)Download as PowerPoint slideHighlights
► Aryl sulfonic acids are better catalysts than H2SO4 for hydrolysis of cellulose.
► 4-Biphenylsulfonic acid gave the highest glucose yield at160 °C.
► Catalytic activity correlates with log D of the sulfonic acids.