文献类型：期刊文献

英文题名：A microkinetic study of isobutene ammoxidation over α-Bi2Mo3O12: Active sites and C-N coupling mechanism

作者：Zheng, Hui-Han[1];Fan, Xin-Ying[1];Lei, Ming[1];Zhou, Xing-Gui[1];Chen, De[1,2];Zhu, Yi-An[1]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, State Key Lab Green Chem Engn & Ind Catalysis, UNILAB, Shanghai 200237, Peoples R China;[2]Norwegian Univ Sci & Technol, Dept Chem Engn, N-7491 Trondheim, Norway

年份：2026

卷号：460

外文期刊名：JOURNAL OF CATALYSIS

收录：;EI(收录号：20262220789207);WOS:【SCI-EXPANDED(收录号:WOS:001785247200001)】；

语种：英文

外文关键词：Isobutene ammoxidation; Reaction mechanism; Bismuth molybdate; DFT; Microkinetic analysis

摘要：The ammoxidation of isobutene to methacrylonitrile represents an environmentally friendly process that efficiently utilizes C4 fractions. However, a detailed molecular-level view of the reaction, such as the activation of the reactants at specific active sites and the starting point for C-N coupling, remains under debate. In this work, the catalytic performance of alpha-Bi2Mo3O12 for isobutene ammoxidation has been studied by density functional theory calculations, chemical informatics approaches, and microkinetic analysis. Calculated results reveal that Bi is responsible for the stabilization of the main carbon-and nitrogen-containing fragments of the reactants while the terminal oxygen atoms at the penta-coordinated Mo sites adjacent to Bi cations serve as the active center for C-H and N-H bond activation. The starting point for C-N coupling is the reaction of methylallyl* which migrates to the Mo=O1 site with NH2* at the Bi site. A full reaction network of isobutene ammoxidation involving 370 species and 1734 elementary steps is then constructed by looping over all the atoms and chemical bonds in the reactants, which is simplified based on chemical bond strengths, kinetic preference, and previous research findings. Further microkinetic analysis shows that the selectivity toward methacrylonitrile depends strongly on temperature, which would be decreased with increasing temperature. Ammonia dissociation is identified as the rate-determining step, as suggested by sensitivity analysis, and lowering the energy barrier may accelerate the overall reaction rate and improve the selectivity toward methacrylonitrile.