Fundamental aspects of radiation-thermal transformations of cellulose and plant biomass

The results of radiation-thermal transformations of cellulose are generalized. It is shown that an event of radiation chemical destruction of polymeric cellulose chain involves local 'explosion' of the glucopyranose ring, resulting in carbon dioxide and compounds with terminal carbonyl and carboxyl groups. Effects of the absorbed radiation dose rate and heating conditions on the product composition and yields are analyzed. It is shown that at high dose rates (≥ 1 kGy s^–1), instantaneous and uniform heating of the whole sample promotes high-energy processes with distillation of liquid condensate mainly composed of furfural and other furan derivatives, which are considered among the most promising components of alternative engine fuels. The mechanism of the radiation-thermal transformations comprising the formation of terminal radical and dehydration, elimination and decomposition of the glucopyranose unit of cellulose to give furfural and formaldehyde is discussed. It is substantiated that utilization of accelerated electrons could provide implementation of direct one-step transformation of cellulose and lignocellulose biomass into components of liquid engine fuel and intermediates for large-scale chemical synthesis. The bibliography includes 99 references.