Radicals from the gas-phase pyrolysis of a lignin model compound: p-coumaryl alcohol
Meng-Xia Xu1, Lavrent Khachatryan1, Alexander Baev2
1Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
Abstract:
The intermediate radicals produced in the gas-phase pyrolysis of one of the main building blocks of lignin - p-coumaryl alcohol (p-CMA) - were investigated using the low temperature matrix isolation technique interfaced with electron paramagnetic resonance spectroscopy (LTMI-EPR). An anisotropic EPR spectrum characterized by a high g-value (>2.0080) and a relatively low saturation coefficient (∼1.40) throughout the high pyrolytic temperature region (700 to 1000 °C) was observed. Theoretical calculations revealed plausible decomposition pathways for p-CMA comprising highly delocalized aromatic radicals. The results provide evidence for a dominant role of oxygen-centered radicals during the pyrolysis of p-CMA.
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