Pyrolytic behavior of lignin-related Α-O-4 contained model compound with addition of methanol

Pyrolysis of lignin-related α-O-4 contained model compound, benzyl phenyl ether (BPE, C₆H₅CH₂OC₆H₅) was conducted in a fixed-bed reactor. The compounds in liquid product from the pyrolysis process were analyzed by GC/FID and GC/MS. Compared to the other three alcohols (CH₃CH₂OH, CH₃CH₂CH₂OH and CH₃CHOHCH₃), methanol was estimated as the optimal hydrogen-donor reagent for the co-pyrolysis with BPE. The yield of the monomeric aromatic compounds was dramatically increased with the addition of methanol to BPE during the co-pyrolysis process (an increment of 29.70 wt.% for BPE with mass concentration of 0.06 g/mL in methanol). An isotopic tracing method (CH₃OD as the tracer) was employed for understanding the role of hydrogen-donor reagent on the cracking of the α-O-4 linkage. Hydroxylic hydrogen in methanol participated in the formation of a certain percentage of monomeric aromatics (except benzene) for the co-pyrolysis process of BPE and methanol. Benzyl (C₆H₅CH₂[rad]) and phenoxy (C₆H₅O[rad]) radicals can be produced from the initial pyrolytic cracking of BPE, while the hydrogen from hydroxylic group in methanol attracted by phenoxy radical is predominant over that of benzyl radical.