Allylic oxidation of hydrocarbons on anodes (ALOHA)
January 2025 – December 2028
The ALOHA project aims to develop an electrochemically assisted process for the selective oxidation of olefins, such as propene, at the allylic position to produce unsaturated acids like acrylic acid. This process replaces dissolved redox mediators with anode-incorporated mediators inspired by N-hydroxyphthalimide. Operating under mild conditions (<100 °C, low O2 content), the approach minimizes voltage and energy requirements and will be demonstrated at TRL 4 using an advanced in-house fabricated electrochemical flow cell.
Initially, the project focuses on screening homogeneous mediators for the selective aerobic oxidation of propylene to acrylic acid, targeting a selectivity of over 95%. The study includes analyzing reaction intermediates under electrochemical conditions to better understand reaction rates and pathways. This knowledge guides the design of highly selective and efficient systems. The next phase involves the development of custom carbon-based, PGM-free anodes that incorporate redox mediators. Using advanced surface modification techniques, mediators are either covalently or non-covalently linked to create stable and robust materials. These electrodes are integrated into an electrochemical system optimized to achieve >100 mA cm-2 current density and >95% selectivity for acrylic acid production. Solvent systems are designed to ensure compatibility with downstream processing while minimizing energy input, striving for one electron transfer per molecule of acrylic acid produced.
Finally, an upscalable electrochemical flow cell for the aerobic allylic oxidation of propylene is designed and developed. This includes quantitative performance testing in flow cell environments with considerations for large-scale process constraints, such as minimizing gradients and enhancing heat exchange. A preliminary multi-tubular electrode arrangement is devised, and the system includes online product monitoring and automated control of gas-feed and recycling conditions, paving the way for efficient industrial implementation.
Initially, the project focuses on screening homogeneous mediators for the selective aerobic oxidation of propylene to acrylic acid, targeting a selectivity of over 95%. The study includes analyzing reaction intermediates under electrochemical conditions to better understand reaction rates and pathways. This knowledge guides the design of highly selective and efficient systems. The next phase involves the development of custom carbon-based, PGM-free anodes that incorporate redox mediators. Using advanced surface modification techniques, mediators are either covalently or non-covalently linked to create stable and robust materials. These electrodes are integrated into an electrochemical system optimized to achieve >100 mA cm-2 current density and >95% selectivity for acrylic acid production. Solvent systems are designed to ensure compatibility with downstream processing while minimizing energy input, striving for one electron transfer per molecule of acrylic acid produced.
Finally, an upscalable electrochemical flow cell for the aerobic allylic oxidation of propylene is designed and developed. This includes quantitative performance testing in flow cell environments with considerations for large-scale process constraints, such as minimizing gradients and enhancing heat exchange. A preliminary multi-tubular electrode arrangement is devised, and the system includes online product monitoring and automated control of gas-feed and recycling conditions, paving the way for efficient industrial implementation.