Oxidative Cracking of Linear Hydrocarbons at Low Temperatures

Câmara, Leôncio Diógenes Tavares; Monteiro, Rafael Sadao; Constantino, Alex M.; Aranda, Donato Alexandre Gomes; Afonso, Júlio Carlos

doi:10.1080/00986445.2010.512548

Cited by 12 publications

(8 citation statements)

References 19 publications

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“…Table presents products identified by chemical family for all C 8 alkanes studied in the present work. These identifications are also confirmed with previous work. ,,−, Except for the TMP, similar oxidation products were identified over the temperature range 373–433 K. TMP analyses did not reveal a significant amount of oxygenated species for the low temperature range (≤393 K), while both C 8 ketones and alcohols where observed at higher temperature (≥403 K). This tends to demonstrate two oxidation regimes of TMP respectively below 400 K and above 400 K in the absence of possible experimental bias for long IP measurements.…”

Section: Resultssupporting

confidence: 90%

“…Although alkanes are major constituents of commercial fuels and well-documented solvents, their respective reactivities and selectivities in autoxidation are poorly understood with nonlinear effects. Thus, within the framework of the full comprehension of fuel stability, this work confirms and extends previous works performed on the autoxidation of normal parraffins ,− to isoparaffins. ,, The present study is in-line with others autoxidation studies performed at IFPEn on aromatics , and naphthenes . All these studies aim at improving the comprehension of the autoxidation of each chemical family present in fuels.…”

Section: Introductionsupporting

confidence: 90%

“…These preliminary studies are mandatory for the establishment of universal structure-reactivity or empirical relations, like the ones commonly used to estimate fuel properties [23][24][25] or gas phase combustion 26,27 . Several works evidenced the structure-reactivity relationship for n-paraffins presenting an increase of the oxidation rate with the chain length 12,15,17,28 . However, the effect of the branching was not widely studied 17,29 and the results available do not present the same conclusions.…”

Section: Introductionmentioning

confidence: 99%

“…All these studies aim at improving the comprehension of the autoxidation of each chemical family present in fuels. These preliminary studies are mandatory for the establishment of universal structure–reactivity or empirical relations, like the ones commonly used to estimate fuel properties − or gas phase combustion. , Several works evidenced the structure–reactivity relationship for n -paraffins presenting an increase of the oxidation rate with the chain length. ,,, However, the effect of the branching was not widely studied , and the results available do not present the same conclusions. The results from Stark et al tend to indicate an increase of the oxidation rate with the branching, while Skolniak et al evidenced a stability increase based on PetroOxy measurements.…”

Section: Introductionmentioning

confidence: 99%

“…26,27 Several works evidenced the structure−reactivity relationship for n-paraffins presenting an increase of the oxidation rate with the chain length. 12,15,17,28 However, the effect of the branching was not widely studied 17,29 and the results available do not present the same conclusions. The results from Stark et al tend to indicate an increase of the oxidation rate with the branching, while Skolniak et al evidenced a stability increase based on PetroOxy measurements.…”

Section: Introductionmentioning

confidence: 99%

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Structure–Reactivity Relationships in Fuel Stability: Experimental and Kinetic Modeling Study of Isoparaffin Autoxidation

et al. 2018

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Liquid phase stability is a major concern in the transportation and the energy field where fuels, lubricants and additives have to be stable from their production site to their application (engine, combustors). Although alkanes are major constituents of commercial fuels and well-documented solvents, their respective reactivities and selectivities in autoxidation are poorly understood. This experimental and modeling study aims at (i) enhancing the current knowledge on alkane autoxidation and (ii) reviewing and correcting the previously established structure reactivity relationships in alkane autoxidation. Experimentally, this study investigates the influence of branching [0-3] and temperature [373-433 K] on the autoxidation of alkanes using four octane isomers: n-octane (C8), 2-methylheptane (MH), 2,5-dimethylhexane (DMH) and the 2,2,4-trimethylpentane(TMP). Induction Period (IP) and qualitative species identification are used to characterize the autoxidation processes of alkanes. The present study also presents new detailed liquid-phase chemical mechanisms obtained with an automated reaction mechanism generator. Experimental results highlight a non-linear effect of the paraffins branching on IP according to compound structure and similar oxidation products for both normal and branched paraffins. The four iso-octanes mechanisms reproduce fairly well the temperature and the branching effects on IP within a factor of 4 for high temperature range (T>403 K). From rate-of-reaction and sensibility analyses, similarities in alkane autoxidation have been evidenced with notably the key role of peroxy radicals in both normal and branched alkane autoxidation. The origin of the structure-reactivity relations was confirmed from a kinetic point of view with the main role of the hydrogen type on the molecule. Finally, based on experimental results available in literature, an empirical relation involving simple descriptors (number of carbons, type of carbons, temperature) is proposed to estimate alkane stability.

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