Lignin is an abundant biopolymer that constitutes ca. 25-30% of dry biomass, that is rich in aromatic oxygen functional groups (phenols, ethers, alcohols, etc) making it a potential renewable energy and chemical resource that would replace or supplement fossil fuel-based resources.   However, much of the thermochemical mechanistic decay pathways that occur during the pyrolysis of compounds involving oxygen substituted molecules are not well understood, making lignin an underutilized resource due to the complex mixture of products that evolve from its pyrolysis.  To approach this complicated problem we investigate the simplified model compound that represents the major arylglycerol-beta-aryl ether, �-O-4 interunit linkage, phenethyl phenyl ether (PPE; PhCaH2C�H2OPh).  We have shown that under liquid phase pyrolysis conditions at ca. 345 �C, decomposition occurs through a multi-step free radical chain pathway.  In recent investigations, the pyrolysis of oxygen substituents on the aromatic positions of PPE showed that selectivity and reaction rates are highly dependent on the functionality type and placement of the substituent. We now seek to understand the influence on reaction rates and product selectivity of substituents at the aliphatic alpha and beta carbons.  Here, we will present the pyrolysis reaction rate and selectivity results of the naturally occurring alpha-hydroxy and beta-hydoxy methyl substituted PPE's.

Radical decomposition pathways of an aliphatic substituted lignin model ompound: Phenethyl phenyl ether

244th National Meeting (2012)

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