Photocatalytic partial oxidation of 4-vinylguaiacol to vanillin over TiO2: a biomimetic approach inspired by spirit aging
Year: 2025
Type: article
Abstract: Inspired by natural oxidative aging processes observed in traditionally matured distilled spirits, we developed a biomimetic photocatalytic approach for the partial oxidation of 4-vinylguaiacol (4-VG)—a ferulic acid-derived aromatic compound—to vanillin using titanium dioxide (TiO 2 ) under ultraviolet (UV) light. The choice of 4-VG as the reaction substrate is rooted in its documented transformation during long-term spirit aging, which we sought to replicate and accelerate under controlled catalytic conditions. By optimizing the pH of aqueous ethanol media, vanillin selectivity reached up to S = 36 % under mild alkaline conditions. The observed pH dependence and solvent effect are consistent with a tentative mechanism involving β‑hydrogen abstraction and radical propagation, which may account for the enhanced selectivity under alkaline conditions. The photocatalytic performance was further evaluated in fermentation-derived multicomponent systems, where inhibitory effects from background silicate anions were identified, whereas low-concentration organic constituents had minimal impact. Ion exchange pretreatment successfully restored photocatalytic activity, underscoring the method's robustness. Product characterization, including sensory validation, confirmed the formation of vanillin, thereby supporting the proposed reaction pathway. This biomimetic oxidation approach offers a sustainable and scalable route for the transformation of bio-derived aromatic compounds under mild, water compatible conditions using non-biological catalysis. It effectively accelerates a naturally slow transformation into a rapid photocatalytic reaction completed within hours.
Source: Results in Chemistry
Authors: Daisuke Ino, Yasuhiro Hashimoto, Satoru Ito, Masayasu Iguchi
Institution: Panasonic (Japan)
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,870
OpenAlex ID: W4413860241