Novelty and significance statement

1. ȮH concentration time-histories were quantitatively measured over a wider temperature range of 1135-1759 K at higher pressures up to 15 atm, where ȮH data had not been obtained before. These new data thus provide additional validation targets for reaction model development of ethanol and even engine combustor design.
2. The chemical kinetic parameters sensitive to ȮH evolution, including unimolecular decomposition reactions of ethanol, H-atom abstractions from ethanol by ȮH and Ḣ, and fuel radical cleavage on beta C-H site, have been modified against the new data. The proposed updated Aramco 3.0 demonstrates improved performance at both micro and macro levels compared to previously published models.