Aldol condensation plays a vital role in the catalytic transformation of biomass-derived oxygenates to useful and value-added chemical products by reducing the oxygen content and increasing carbon chain length through C-C coupling .Most study on aldol condensation focused on vapor phase process although biomass-derived oxygenates, including carboxylic acid, aldehydes, ketones, are stable in an aqueous solution. Water itself is one of the products from aldol condensation and its effect on the reaction are expected to increase as the reaction progresses. Aldol condensation of acetone and formaldehyde co-feeding with water had been previously reported.However, the role of water is not clearly understood. In this work, condensation of formaldehyde and acetone on an anatase TiO2 (101) surface in vapor and in liquid water environment are comparatively studied using density functional theory (DFT) calculations. The effects of aqueous phase on the reaction mechanism and the kinetically relevant steps including α-H abstraction, C-C coupling, and hydrogenation steps are elucidated. The results showed that the hydrogen-bonding network in the aqueous phase around the active intermediates are important, not only providing different additional stabilities for reaction and transition states, but also altering the reaction pathways via proton transfer mechanism. This work provides the fundamental insights into how the aqueous phase affects aldol condensation reaction mechanisms in the catalytic conversion of biomass-derived oxygenates.

Theoretical investigation of aldol condensation of formaldehyde and acetone on anatase TiO2(101) surface

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.