Kinetics and Catalyst Deactivation Studies during Hydroxyalkylation–Alkylation of Biomass-Derived Furans over a Hierarchical H–Y Zeolite

Hydroxyalkylation–alkylation (HAA) of lignocellulosic biomass-derived compounds can be leveraged to produce long-carbon-chain precursors that can be further upgraded for use in sustainable aviation fuels (SAFs). Hierarchical H–Y zeolites have been shown to be highly active for HAA reactions between 2-methylfuran (2-MF) and furfural (FF), which resulted in C 15 jet fuel precursor yields of ∼72 mol %. 1 To establish the kinetic parameters for modeling the temporal decay of hierarchical H–Y zeolites in continuous-flow systems, an kinetic analysis of HAA over a hierarchical H–Y zeolite was conducted using the Langmuir–Hinshelwood kinetic model. The reaction has an intrinsic activation energy of 17.0 kcal·mol –1 . Deactivation studies showed that the hierarchical H–Y zeolite showed a moderate coke tolerance when used for the first time in the HAA reactions (i.e., prior to recycling runs). The high coke tolerance was attributed to its high mesopore-to-micropore ratio, which enhanced reactant access to active sites. However, a significant catalyst deactivation during regeneration (i.e., calcination) was associated with the water produced as a byproduct of the alkylation reaction. The produced water remains adsorbed within the zeolite framework, which induces structural changes and irreversible deactivation upon calcination.