(532e) Ketonization and Etherification Reactions for Sustainable Biomass Conversion

Optimal and sustainable chemical pathways are critical to producing longer chain distillates biomass-derived fuels for heavy-duty transportation. The ketonization and etherification reactions are promising catalytic processes for producing ketones and branched ethers for sustainable transportation fuels. In this contribution, we highlight two examples of computational studies of the fundamental reaction mechanisms and rational design of catalysts with experiment validations for ketonization and etherification processes. In the first example, we investigate the role of Ca dopant on acetic acid ketonization over CeO₂ catalyst. We calculate that a Ca dopant stabilizes the intermediates and lowers the reaction energies of the C-C coupling and water formation steps, which are rate-limiting, and we predict an optimal size of three Ca ensembles to minimize the reaction energies of the above steps. In the second example, we provide insights into the reaction mechanism of etherification of n-butanol and 4-heptanone on Pd/NbOPO₄ catalyst. From first principles simulations, we identify a reductive pathway via hemi-ketalization on NbOPO₄ and enol ether pathway on Pd, and we predict that Pd nanoparticles of size about 5 nm reach the highest mass activity for ether production. Our combined computational and experimental investigation provide molecular-level insights into the reaction mechanisms, which is essential for optimizing catalytic conditions for sustainable biomass conversion.