Ab Initio Kinetics for H‐atom Abstraction Reactions From Low‐Carbon Alcohols and Ethers by NH ₂ Radical

ABSTRACT Alcohols and ethers serve as promising reactive green fuels as additives to blend with ammonia for modern engines. The H‐atom abstraction reactions by NH 2 radicals from fuels are crucial in the combustion process of ammonia and fuel mixtures. In this work, the kinetics of H‐atom abstraction reaction by NH 2 radicals from C 1 –C 4 alcohols and ethers are systematically studied. Quantum chemical calculations at the QCISD(T)/CBS//M06‐2X/6‐311++G(d,p) level were performed to optimize geometries and compute vibrational frequencies for all relevant species. Single‐point energy was determined using QCISD(T)/cc‐pVDZ, and QCISD(T)/cc‐pVTZ level of theories, with basis set corrections using MP2/cc‐pVDZ, MP2/cc‐pVTZ, and MP2/cc‐pVQZ methods. One‐dimensional hindered rotor potentials were obtained with 10° increment using M06‐2X/cc‐pVTZ method. High‐pressure limit rate constants for all reaction channels were calculated by using Master Equation System Solver with conventional transition state theory over a range of temperature (300–2000 K). The computed rate constants exhibit good agreement with the data available in the literature. Moreover, key regioselectivity patterns emerge: for alcohols, k tertiary > k secondary > k primary , and k α > k γ > k β ; for ethers: k tertiary > k secondary > k primary , and k α > k β. The impact of the carbon chain length and branched structure on the rate constants has also been investigated. Substituent effects reveal that branching in the carbon chain consistently decreases rate constants at identical abstraction sites across both alcohol and ether systems. This study provided theoretical support for the accurate construction of the ammonia/alcohol and ammonia/ether reaction kinetic mechanism, and to develop a comprehensive database to support practical applications in engine simulation, emission control, and sustainable fuel formulation strategies.