Chemical aspects of the autoignition of hydrocarbonair mixtures

Cox, R. A.; Cole, Jerald A.

doi:10.1016/0010-2180(85)90001-x

Cited by 251 publications

(104 citation statements)

References 15 publications

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“…Further, it was suggested that a radical chain of peroxy radical formation and intramolecular H shifts could be the path to ELVOC formation, resulting in multiple hydroperoxides with increasing oxygen content in steps of 32 Da . H migration to peroxy radicals is known at elevated temperatures and for specific atmospheric radicals (Cox and Cole, 1985;Glowacki and Pilling, 2010;Jorand et al, 2003;Perrin et al, 1998) and the mechanism is commensurable with recent findings for the autoxidation of isoprene and related compounds (Crounse et al, 2012(Crounse et al, , 2013(Crounse et al, , 2011Praplan et al, 2012) and with quantum-mechanical calculations, regarding the oxidation of monoterpenes (Vereecken and Francisco, 2012;Nguyen et al, 2010;Peeters et al, 2009;Vereecken et al, 2007). Jokinen et al (2014) demonstrated HOM formation in detail for limonene, a monoterpene.…”

Section: T F Mentel Et Al: Formation Of Highly Oxidized Multifunctsupporting

confidence: 70%

Formation of highly oxidized multifunctional compounds: autoxidation of peroxy radicals formed in the ozonolysis of alkenes – deduced from structure–product relationships

Mentel¹,

Springer²,

et al. 2015

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Abstract. It has been postulated that secondary organic particulate matter plays a pivotal role in the early growth of newly formed particles in forest areas. The recently detected class of extremely low volatile organic compounds (ELVOC) provides the missing organic vapors and possibly contributes a significant fraction to atmospheric SOA (secondary organic aerosol). The sequential rearrangement of peroxy radicals and subsequent O 2 addition results in ELVOC which are highly oxidized multifunctional molecules (HOM). Key for efficiency of such HOM in early particle growth is that their formation is induced by one attack of the oxidant (here O 3 ), followed by an autoxidation process involving molecular oxygen. Similar mechanisms were recently observed and predicted by quantum mechanical calculations e.g., for isoprene. To assess the atmospheric importance and therewith the potential generality, it is crucial to understand the formation pathway of HOM.To elucidate the formation path of HOM as well as necessary and sufficient structural prerequisites of their formation we studied homologous series of cycloalkenes in comparison to two monoterpenes. We were able to directly observe highly oxidized multifunctional peroxy radicals with 8 or 10 O atoms by an Atmospheric Pressure interface High Resolution Time of Flight Mass Spectrometer (APi-TOF-MS) equipped with a NO − 3 -chemical ionization (CI) source. In the case of O 3 acting as an oxidant, the starting peroxy radical is formed on the so-called vinylhydroperoxide path. HOM peroxy radicals and their termination reactions with other peroxy radicals, including dimerization, allowed for analyzing the observed mass spectra and narrowing down the likely formation path. As consequence, we propose that HOM are multifunctional percarboxylic acids, with carbonyl, hydroperoxy, or hydroxy groups arising from the termination steps. We figured that aldehyde groups facilitate the initial rearrangement steps. In simple molecules like cycloalkenes, autoxidation was limited to both terminal C atoms and two further C atoms in the respective α positions. In more complex molecules containing tertiary H atoms or small, constrained rings, even higher oxidation degrees were possible, either by simple H shift of the tertiary H atom or by initialization of complex ring-opening reactions.

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Section: T F Mentel Et Al: Formation Of Highly Oxidized Multifunctsupporting

confidence: 70%

Formation of highly oxidized multifunctional compounds: autoxidation of peroxy radicals formed in the ozonolysis of alkenes – deduced from structure–product relationships

Mentel¹,

Springer²,

et al. 2015

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“…Most of these models assume that the chemical details of fuel autoignition are so complex that many simplifications are essential to be able to simulate the oxidation process. Some of the most prominent of these simplified model treatments of hydrocarbon ignition are the "Shell Model" [57] and related developments by Hu and Keck [58] and Cox and Cole [59]. A recent survey and critical analysis of these simplified approaches by Griffiths [60] has summarised the strengths and limitations of these models.…”

Section: Low Temperature Mechanismmentioning

confidence: 99%

A comprehensive modeling study of iso-octane oxidation

Curran

2002

Combustion and Flame

1,235

722

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A detailed chemical kinetic mechanism has been developed and used to study the oxidation of iso-octane in a jet-stirred reactor, flow reactors, shock tubes and in a motored engine. Over the series of experiments investigated, the initial pressure ranged from 1 to 45 atm, the temperature from 550 K to 1700 K, the equivalence ratio from 0.3 to 1.5, with nitrogen-argon dilution from 70% to 99%. This range of physical conditions, together with the measurements of ignition delay time and concentrations, provide a broad-ranging test of the chemical kinetic mechanism. This mechanism was based on our previous modeling of alkane combustion and, in particular, on our study of the oxidation of n-heptane. Experimental results of ignition behind reflected shock waves were used to develop and validate the predictive capability of the reaction mechanism at both low and high temperatures. Moreover, species' concentrations from flow reactors and a jet-stirred reactor were used to help complement and refine the low and intermediate temperature portions of the reaction mechanism, leading to good predictions of intermediate products in most cases. In addition, a sensitivity analysis was performed for each of the combustion environments in an attempt to identify the most important reactions under the relevant conditions of study.

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“…The understanding of this mechanism was then improved successively by Pollard [47], Cox and Cole [48] and Walker and Morley [49]. Figure 2 shows a simplified scheme of the main reactions, which are now usually admitted to model the oxidation of an alkane (RH).…”

Section: 1/ Main Chemical Features Of Their Oxidationmentioning

confidence: 99%

“…Following this, progress was made in the development of a priori reduced mechanisms (to be distinguished from a posteriori reduced mechanisms obtained by reduction techniques from detailed mechanisms), including elementary steps, but involving globalized species (alkanes were represented by RH, all alkyl radicals by "R•", all peroxy radicals by "ROO•"…) such as the models of Cox and Cole [48], Hu and Keck [63] and the unified one of Griffiths et al [23]. This last model was particularly well detailed for a reduced model, as it distinguished the different types of alkyl radicals and of isomerizations of peroxy radicals.…”

Section: 2a/ Mechanisms Written Without Computer Helpmentioning

confidence: 99%