The efficient transformation of lignin to value-added aromatic chemicals remains limited by harsh reaction conditions, low catalyst selectivity, and suboptimal yields. Despite these challenges, bio-derived chemicals (e.g., vanillin, vanillic acid, benzoic acid) are desirable molecules that have been widely applied in the food/beverage and fragrance industries. In this work, we present a synergistic CuO/graphene oxide (GO) catalyst that can selectively cleave both C-O and C-C bonds in lignin under mild conditions (160°C, ambient pressure), achieving a 20.14 wt.% total aromatic yield with 9.00 wt. % of vanillin. To maximize aromatic yield from pinewood lignin, reaction parameters were optimized using an integrated Design of Experiments (DoE) and Bayesian Optimization framework, which efficiently navigated multidimensional variable spaces (e.g., temperature, pH, copper loading on the catalyst). Mechanistic studies revealed a pathway by forming enol ether intermediate first, followed by dioxetane intermediate. The density functional theory (DFT) calculations confirm the energetics and selectivity of this pathway. In conclusion, the work presents an economic data-driven method of selectively converting lignin into aromatic compounds with a decent yield. This new route will inspire the development of sustainable biorefinery processes using a hybrid experimental-computational strategy to avoid traditional trial-and-error limitations.
