Hydrolysis of Cellulose by Using Catalytic Amounts of FeCl2 in Ionic Liquids

Authors:
Publisher website
Google Scholar
Abstract
Microcrystalline cellulose (MCC) is hydrolyzed to an appreciable extent (70 %) by using 1‐(4‐sulfonic acid) butyl‐3‐methylimidazolium hydrogen sulfate (IL‐1) as effective catalyst. Valuable chemicals, such as 5‐hydroxymethyl furfural (HMF) and furfural, are obtained in relatively high yields (15 % and 7 %, respectively). Interestingly, the introduction of FeCl2 as catalyst into IL‐1 further enhances the catalytic activity, as proved by the higher conversion of MCC (84 %) and higher yields of HMF and furfural (34 % and 19 %, respectively) under the same experimental conditions, although small amounts of levulinic acid (LA) and total reducing sugars (TRS) were also found. The hydrolysis of MCC scarcely proceeded, or showed a lower efficiency, in the absence of catalyst (4 %) or with Al2O3 (7 %), inorganic acids (≤65 %), or several other ionic liquids (≤24 %) as catalyst. Dimers of furan compounds were detected as the main byproducts, as analyzed by HPLC–MS; from the mass spectrometry analysis, the components of the gas‐phase products were determined to be methane, ethane, CO, CO2, and H2. A mechanism to explain the high activity of FeCl2 in the IL‐1 system is proposed. Recycling of the IL‐1 catalyst showed an almost constant activity during five successive trials. The simple and effective catalyst system may prove valuable in facilitating the energy‐efficient and cost‐effective conversion of biomass into biofuels and platform chemicals.

This publication has 32 references indexed in Scilit: