Species　concentrations　for　2-methyl-2-butene　oxidation　and　pyrolysis　were　measured　in　a　jet-stirred　reactor　at　atmospheric　pressure,　in　the　temperature　range　of　650　to　1200　K　and　the　residence　time　of　1.5　s.　The　model　presented　in　literature　was　modified　based　on　the　high-level　quantum　calculated　rate　coefficients　published,　including　1,2-dimethyl-allyl　(AC5H9[sbnd]C)　+　HO2,　1,2-dimethyl-allyl　+　O2,　1,2-dimethyl-allyl　+　1,2-dimethyl-allyl,　isoprene　+　H　reaction　classes.　The　modified　model　was　validated　against　the　measured　species　concentrations,　ignition　delay　times　and　laminar　flame　speeds.　The　modified　model　can　accurately　predict　experimental　data　under　various　conditions.　Moreover,　flux　analysis　showed　that　the　major　pathways　were　abstraction　reactions　that　consumed　more　than　40%　2-methyl-2-butene.　At　lower　temperatures,　reactions　of　HO2　addition,　O2　addition　and　radical　self-combination　were　the　dominant　consumption　path　for　allylic　pentenyl　radicals.　Sensitivity　analysis　showed　that　HO2　additions　to　AC5H9[sbnd]C　radicals,　forming　AC5H9[sbnd]COOH,　BC5H9-AOOH,　and　C5H9O　oxy-radicals　+　OH　played　important　roles　in　promoting　the　overall　reactivity.　©　2022　The　Combustion　Institute