UNCATALYZED SOLVOLYSIS OF WHOLE BIOMASS HEMICELLULOSE BY HOT COMPRESSED LIQUID WATER

Samples of six woody and four herbaceous biomass species were washed with compressed, liquid water for 0-15 min at 200-230-degrees-C. Between 40 and 60% of the sample mass was solubilized. In all cases, 100% of the hemicellulose was solubilized, of which 90% (on average) was recoverable as monomeric sugar. Concurrently, between 4 and 22% of the cellulose and 35 and 60% of the lignin were also solubilized. The solvolysis process is so facile that the results are practically independent of temperature and time within the range studied. The observed variations occurred primarily as a function of species. High lignin solubilization apparently reduced the ability to recover hemicellulose sugar.