Secondary decomposition of levoglucosan in pyrolytic production from cellulosic biomass

Levoglucosan (1,6-anhydro-β-d-glucopyranose) is a major pyrolysis product from cellulose. To understand the secondary decomposition behavior in pyrolytic production of levoglucosan from cellulosic biomass, influences of the pyrolysis vapor from wood or wood constituent polymers on the recovering process of levoglucosan were studied at 400 °C (30 mmHg). Japanese cedar (Cryptomeria japonica, a softwood) and Japanese beech (Fagus crenata, a hardwood) wood samples, cellulose, xylan (a hemicellulose) and the milled wood lignins isolated from the wood samples were used as the substances for production of the pyrolysis vapor. Since levoglucosan and other substances were placed separately in a dual-space reactor to eliminate their direct contact, the interaction is expected in vapor-phase. Solid/liquid-phase interaction is also possible after condensation of the vapor on the reactor wall with lower temperature. The cellulose- and lignin-derived pyrolysis vapors reduced the recovery of levoglucosan substantially, while the influences of the vapors from xylan and the substances containing xylan were comparatively very small. Such decomposition induced by the cellulose- and lignin-derived vapors was inhibited in the presence of the xylan-derived pyrolysis vapor.