ABSTRACT A fundamental understanding of catalyst deactivation and regeneration is essential for developing sustainable catalytic pyrolysis processes for lignocellulosic biomass conversion. Herein, the effect of alumina regeneration on the catalytic pyrolysis of ferulic acid, a lignin‐derived model compound, was investigated using kinetic analysis combined with FTIR, TPD–MS, XPS, TEM, XRD, thermogravimetry, and DFT calculations. Comparative kinetic analysis showed that the apparent activation energies of key reactions, including decarboxylation, demethoxylation, and the formation of 4‐vinylguaiacol, guaiacol, phenol, and other aromatic products, increase by 4–23 kJ mol − 1 after catalyst regeneration, indicating partial modification of the alumina surface. DFT calculations revealed that 4‐vinylguaiacol formation proceeds preferentially via a surface‐assisted acidic decarboxylation pathway involving alumina‐bound intermediates, whereas alternative surface interactions generate strongly bound species that may contribute to catalyst deactivation. Combined experimental and theoretical evidence indicates that surface‐bound phenolate complexes act as precursors to carbon deposition. These species undergo styrene‐like polymerization on alumina, forming a polymeric carbonaceous layer that decomposes upon heating, releasing aromatic products and progressively forming extended polyaromatic carbon domains. The proposed mechanism is supported by TEM, FTIR, XPS, and TPD–MS results. These findings establish a unified mechanistic framework linking catalytic decarboxylation, carbon‐layer formation, and catalyst deactivation during biomass conversion.
Kulik et al. (Tue,) studied this question.