MECHANISM OF DEPOLYMERIZATION OF CELLULOSE BY ETHYLENE-GLYCOL SOLVOLYSIS

By treating wood at a high temperature (300-350-degrees-C) for a short period of time (4-6 min) using ethylene glycol as solvent, a fraction of the cellulose and all the lignin are solubilized. The solid residu e consists of highly crystalline pure cellulose I having low degree of polymerization. From spin-diffusion NMR experiments, the presence of small mobile domains located inside the rigid (crystalline) structure is shown. This is an indication that the depolymerization occurs insid e the ordered area of cellulose during high temperature solvolysis. A physico-chemical mechanism based on random glucosidic bond rupture una ffected by accessibility constraints is proposed. The role played by e thylene glycol, as possibly involved in hydrogen bonding with cellulos e or acting as a radical scavenger, is discussed.