Formation of aromatic hydrocarbons from co-pyrolysis of lignin-related model compounds with hydrogen-donor reagents

Co-pyrolysis of lignin-related model compounds (phenethyl phenyl ether, syringol, guaiacol and phenol) with methanol, acetone and diethyl ether was conducted in a fixed-bed reactor. Typical aromatic compounds in liquid product were analyzed by GC/MS, including aromatic hydrocarbons and phenols. The yield of aromatic hydrocarbons (especially for benzene and toluene) from the pyrolysis of the monomeric model compounds was dramatically increased with the addition of acetone, while the production of phenols from pyrolysis of monomeric model compounds was correspondingly decreased. Acetone as the suitable additive for the production of aromatic hydrocarbons was employed for the co-pyrolysis with PPE. The formation pathways of aromatics (especially for benzene, toluene and phenol) during the co-pyrolysis process were proposed involving a series of radical-chain reactions. The dehydroxylation reactions of phenols to aromatic hydrocarbons can be enhanced during the pyrolysis of monomeric compounds in presence of different hydrogen-donor reagents.