Hydrolysis of cellulose to glucose at the low temperature of 423 K with CaFe2O4-based solid catalyst

Abstract

Weakly magnetic CaFe2O4 was synthesized by calcination of the hydroxides co-precipitated from aqueous Ca(NO3)2·6H2O and Fe(NO3)3·9H2O solutions in the presence of urea. Microcrystalline cellulose was treated with ionic liquid (IL) [AMIM]Cl (1-allyl-3-methylimidazolium chloride) and hydrolyzed in the presence of the catalyst at 423K. No IL contamination was detected in the treated cellulose by energy-dispersive X-ray spectrometry (EDX). A maximum hydrolysis yield of 49.8% and glucose selectivity of 74.1% was obtained. The catalyst was separated and reused four times, showing only a slight decrease in activity. The catalyst was stable and only minor leaching into water occurred as indicated by inductively coupled plasma atomic emission spectrometry (ICP), X-ray diffraction (XRD), and temperature programmed desorption (TPD) measurements and a neutral pH after reactions. Hydrolysis of cellulose with CaFe2O4 catalyst combined with [AMIM]Cl pretreatment is a green, energy-saving and efficient process.