PROCESS FOR ISOLATING LEVOGLUCOSAN FROM PYROLYSIS LIQUIDS

摘要

An improved process is described for isolating levoglucosan from pyrolysis liquids obtained by the pyrolysis of lignocellulosic material, such as wood. The pyrolysis liquid is first mixed with a base to raise the pH to above 8, preferably 10-12, to convert lignin, phenolic and other weakly acidic components to insoluble salts. The remaining basetreated liquid portion is then removed from the insoluble material and this separated, base-treated liquid portion is then mixed with an acid to reduce the pH thereof to the range 6-7. This remaining acid-treated liquid portion is separated from any insoluble material formed during the acid treatment and water is then removed from the separated liquid portion to obtain an anhydrous material containing levoglucosan. This anhydrous material is then contacted with a solvent selected from acetone and ethanol to selectively extract the levoglucosan in pure form.