Small methyl ketones are known to have high octane numbers, impressive knock resistance, and show low emissions of soot, NO_x, and unburnt hydrocarbons. However, previous studies have focused on the analysis of smaller ketones and 3-pentanone, while the asymmetric 2-pentanone (methyl propyl ketone) has not gained much attention before. Considering ketones as possible fuels or additives, it is of particular importance to fully understand the combustion kinetics and the effect of the functional carbonyl group. Due to the higher energy density in a C₅-ketone compared to the potential biofuel 2-butanone, the flame structure and the mole fraction profiles of species formed in 2-pentanone combustion are of high interest, especially to evaluate harmful species formations. In this study, a laminar premixed low-pressure (p = 40 mbar) fuel-rich (ϕ = 1.6) flat flame of 2-pentanone has been analyzed by vacuum-ultraviolet photoionization molecular-beam mass-spectrometry (VUV-PI-MBMS) enabling isomer separation. Quantitative mole fraction profiles of 47 species were obtained and compared to a model consisting of an existing base mechanism and a newly developed high-temperature sub-mechanism for 2-pentanone. High-temperature reactions for 2-pentanone were adapted in analogy to 2-butanone and n-pentane, and the thermochemistry for 2-pentanone and the respective fuel radicals was derived by ab initio calculations. Good agreement was found between experiment and simulation for the first decomposition products, supporting the initial branching reactions of the 2-pentanone sub-mechanism. Also, species indicating low-temperature chemistry in the preheating zone of the flame have been observed. The present measurements of a 2-pentanone flame provide useful validation targets for further kinetic model development.

已知小型甲基酮具有较高的辛烷值，出色的抗爆震性，并且烟灰，NO _x和未燃烧的碳氢化合物排放量低。但是，以前的研究集中在分析较小的酮和3-戊酮，而不对称的2-戊酮（甲基丙基酮）以前并没有引起太大的关注。考虑到酮是可能的燃料或添加剂，充分了解燃烧动力学和官能羰基的作用尤为重要。由于C _5中的能量密度较高与潜在的生物燃料2-丁酮相比，2-酮在2-戊酮燃烧中形成的物种的火焰结构和摩尔分数分布图尤其令人关注，特别是对于评估有害物种的形成。在这项研究中， 通过真空-紫外光电离分子束质谱（VUV-PI-MBMS）分析了2-戊酮的层流预混合低压（p  = 40 mbar）富燃料（ϕ = 1.6）扁平火焰）进行异构体分离。获得了47个物种的定量摩尔分数分布图，并将其与一个模型进行了比较，该模型由一个现有的基本机理和一个新开发的2-戊酮高温亚机理组成。将2-戊酮的高温反应类似于2-丁酮和n-戊烷和2-戊酮和各自的燃料自由基的热化学是通过从头算来得出的。在实验和模拟之间发现了第一个分解产物的良好协议，支持了2-戊酮亚机理的初始支化反应。另外，已经观察到指示火焰的预热区域中的低温化学的物质。目前对2-戊酮火焰的测量为进一步的动力学模型开发提供了有用的验证目标。