Continuous photocatalytic preparation of hydrogen peroxide with anthraquinone photosensitizers

Hydrogen peroxide (H 2 O 2 ) is a versatile oxidant, and its eco-friendly synthesis via visible light and air oxygen is crucial. Anthraquinone compounds were employed as homogeneous photocatalysts for alcohol oxidation, yielding H 2 O 2 under visible light. Instead of using traditional catalyst library screening, a model based on density functional theory was proposed to structurally optimize anthraquinone photocatalysts, resulting in the discovery of a novel catalyst significantly boosting H 2 O 2 generation (up to 621.2 mM h −1 intermittently). Continuous flow reactor design improvements can enhance chemical transformation efficiency, as demonstrated by continuous H 2 O 2 production using 2,6-di- tert -butyl anthraquinone. When isopropanol was used as the hydrogen atom donor, H 2 O 2 production rates reached 3950.6 mM h −1 in a 7-minute reaction, with a space-time yield of 7.90 mol (L h) −1 , showcasing promising advancements in green H 2 O 2 synthesis. A design model for anthraquinone catalysts was established based on DFT calculations. The designed anthraquinone catalyst was applied in continuous flow strategy, achieving H 2 O 2 production rates of 3950.6 mM/h under visible light irradiation.