Formation and Characteristics of Reaction Intermediates from the Fast Pyrolysis of NaCl- and MgCl2-Loaded Celluloses

This study investigates the formation and characteristics of reaction intermediates from the fast pyrolysis of NaCl- and MgCl2-loaded celluloses (75-106 mu m) at 150-400 degrees C. The loading of MgCl2 lowers the onset temperature of cellulose pyrolysis. At low temperatures (e.g., 150 degrees C), the loading of MgCl2 increases the yield of water-soluble intermediates and significantly enhances the formation of sugar and anhydro-sugar oligomers. However, the effect of NaCl loading is minimal under the similar conditions. The results suggest that the loading of MgCl2 catalyzes the cleavage of both hydrogen bonds and glycosidic bonds during cellulose pyrolysis at low temperatures. At increased temperatures (250 degrees C and above), both the loading of NaCl and the loading of MgCl2 greatly enhance the destruction of sugar ring structures within the pyrolyzing cellulose. The conversion of water-insoluble solid into water-soluble intermediates, which are important precursors for volatile formation, is reduced significantly, leading to an increase in char yield.