The Co-catalyst Effects of Mn(II), Zn(II), and Cr(III) Chlorides on Acidic Ionic Liquid Catalyzed Synthesis of Value-added Products from Cellulose in Aqueous Ethanol

Abstract

Processing of cellulose can be used to produce value added renewable feedstock chemicals. Catalytic depolymerization and processing of cellulose can be used to produce value added renewable feedstock chemicals. Development of an acidic ionic liquid - metal ion chloride catalyst system based single-reactor method for processing cellulose to value added products. The effect of metal chlorides as co-catalysts on 1-(1-propylsulfonic)-3-methylimidazolium chloride acidic ionic liquid catalyzed degradation of cellulose in 40 % (v/v) aq. ethanol was studied by measuring levulinic acid, ethyl levulinate and 5-hydroxymethylfurfural yields. In experiments with Mn(II), Zn(II) chloride co-catalysts at 160 and 170 °C for 12 h, the initial yields of ethyl levulinate and 5-hydroxymethylfurfural improved from ~ 7 % to ~ 12-15% due to co-catalytic effects. The highest enhancements in ethyl levulinate yields were observed with CrCl3, where the yield increased from 6 to 27 % with the addition of 10 mol% co-catalyst. All three transition metal chlorides studied produced improvements in yields of secondary products, ethyl levulinate and 5-hydroxymethylfurfural in acidic ionic liquid catalyzed degradation of cellulose in aqueous ethanol. The most significant enhancements in ethyl levulinate yields were observed with CrCl3 as a co-catalyst. none