Thermal behavior of some reducing disaccharides

Effect of chemical pretreatments on the thermal degradation of corn husk lignocellulosics

“…Furthermore, many physical and chemical factors such as temperature, pressure, size of sample, atmosphere, purity, and homogeneity of the carbohydrate material are important in affecting the degradation pathways. Most studies on purified cellulose and model small molecular weight compounds indicate that thermal degradation leads to a variety of products that can be derived by more than one pathway, as shown in the over-simplified scheme of Figure 2 (Shafizadeh and McGinnis, 1971; Shafizadeh et al, 1971; Shafizadeh and Fu, 1973; Shafizadeh and Lai, 1975;Furneaux and Shafizadeh, 1979;Liskowitz et al, 1980;Shafizadeh, 1983). The suggested mechanisms for molecular rearrangement/ transformations that take place include cleavage of glycosidic linkages (via free-radical formation and/or transglycosylation), formation of anhydro sugars (mainly levoglucosan) and tar (via transglycosylation, condensation, and dehydration), and decomposition into carbonaceous char and volatiles (via dehydration, disproportionation, and fission reactions).…”