Development of Oxygen Scavenger Additives for Future Jet Fuels. A Role for Electron-Transfer-Initiated Oxygenation (ETIO) of 1,2,5-Trimethylpyrrole?

Beaver, Bruce; Sharief, Vaqar; Teng, Yun; DeMunshi, R.; Guo, J. P.; Katondo, and E.; Gallaher, Daniel D.; Bunk, David M.; Grodkowski, and J.; Neta, P.

doi:10.1021/ef990165x

Cited by 9 publications

(3 citation statements)

References 24 publications

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“…They designated this reaction as electron-transfer-initiated oxygenation (ETIO). They illustrated this theory with the examples of the oxidation of 1,2,3,4-tetrahydrocarbazole (THC) and 3-methylindole (3MI) as oxygen scavenger additives and, later, with 2,5dimethylpyrrole (DMP), 36 triphenylphosphine (TPP), 37 1,2,5trimethylpyrrole (TMP), 38 and dicyclohexylphenylphosphine (DCP). 39 For all of the compounds, they analyzed product distributions, considered kinetic issues, and proposed a detailed mechanism.…”

Section: Mechanisms and Kinetic Aspectsmentioning

confidence: 99%

Gum Formation in Gasoline and Its Blends: A Review

Pradelle¹,

Braga²,

Martins³

et al. 2015

Energy Fuels

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Gasoline is a volatile mixture of hydrocarbons that is used in spark-ignition (SI) engines. It is a complex mixture composed of olefinic, paraffinic, naphthenic, and aromatic hydrocarbons (C 4 −C 12 ), among other substances in a smaller concentration. In several countries, such as Brazil, ethanol is used pure as a renewable fuel for SI engines, especially in flex fuel engines, and/or an additive to improve the octane number of gasoline. During storage, some classes of hydrocarbons in gasoline blends, particularly olefins and diolefins, are able to slowly react, at ambient temperatures, with the oxygen in the air. The formed oxidation products are responsible for the formation of an insoluble solid, commonly called deposits or gums, which sticks to the metal surfaces along the vehicle-fuel system, from the tank to the combustion chamber. Accumulation of these products can cause engine wear and can have adverse effects on engine efficiency, performance, emission, and durability. Consequently, it is necessary to predict gasoline blend behavior and prevent gum formation, improving gasoline quality and using additives. Even if the number of publications dedicated to gum formation in gasoline blends is reduced, results available in the literature for other fuels can be applied to the gasoline issue. This review intends to define more precise fuel stability concepts and what is considered a gum. It also aims to present the oxidation mechanism involved in gum formation, determine the main parameters influencing gum deposition in gasoline blends, and describe the experimental tools available to measure gum content.

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Section: Mechanisms and Kinetic Aspectsmentioning

confidence: 99%

Gum Formation in Gasoline and Its Blends: A Review

Pradelle¹,

Braga²,

Martins³

et al. 2015

Energy Fuels

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“…This mechanism occurs at temperatures higher than the storage temperaturetypically those encountered in the engineand is known as thermal oxidative degradation. Such mechanisms have been studied for years in jet fuels and diesel oil. − These phenols are oxidized into quinones, which then undergo oxidative coupling reactions, which increase the molecular weight.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Unwashed and Washed Gum Content in Brazilian Gasoline–Ethanol Blends during Prolonged Storage: Application of a Doehlert Matrix

et al. 2016

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Gasoline is a volatile mixture of hydrocarbons that is used in spark ignition engines. It is a complex mixture composed of inflammable olefinic, paraffinic, naphthenic, and aromatic hydrocarbons (C 4 −C 12 ). It presents low contents of oxygenates and traces of sulfur, nitrogen, and metals, which introduce instability to the mixture. In several countries, such as Brazil, ethanol is used purely as a renewable fuel or as an octane improver in blends with gasoline, especially in flex fuel engines. Nevertheless, some compounds in the fuel react slowly, at room temperature, with atmospheric oxygen, and with each other. The process is observed throughout the entire fuel production and use process and increases fuel density. These high-molar-mass insoluble oxidation products are commonly called gums and form deposits throughout the vehicle fuel system. Their accumulation has adverse effects on engine efficiency, performance, and durability, in the form of incomplete combustion, engine wear, and higher pollutant emissions. Consequently, it is necessary to prevent gum formation by improving gasoline quality and using additives. A prediction of gasoline blends behavior is also an important tool to assess critical conditions. This work studied the influence of aging period, temperature, and addition of anhydrous ethanol concentration on unwashed and washed gum content of Brazilian gasoline−ethanol blends. The effect of an additive was also evaluated, by comparing the results of regular and additivated gasolines. This study also defined predictive mathematic models for the studied properties through a Doehlert matrix with three factors, from which robustness was assessed.

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“…In Scheme , middle distillate oxidative degradation begins with the oxidation of phenolic compounds indigenous to jet fuel , via a peroxyl radical chain mechanism. ,, Phenol oxidation by a peroxyl radial yields a resonance-stabilized radical, which presumably reacts with a second equivalent of peroxyl radical, ultimately yielding benzoquinone (step 3 in Scheme ). Quinones are robust electrophiles that can act as molecular coupling promoters.…”

Section: Introductionmentioning

confidence: 99%

Oxidative Stability of Middle Distillate Fuels. Part 1: Exploring the Soluble Macromolecular Oxidatively Reactive Species (SMORS) Mechanism with Jet Fuels

et al. 2011

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The soluble macromolecular oxidatively reactive species (SMORS) mechanism has recently been applied to jet fuel thermal oxidative degradation at high temperatures (250–550 °C). The primary purpose of this work is to further test the extant SMORS mechanism with carefully designed experiments at lower temperatures. First, synthetic SMORS precursors, 2-methylindole and 1,4-benzoquinone, were doped into a stable Jet A-1 in both mono- and oligomeric forms. Flask oxidative stress of these solutions at 90 °C for 60 min with an oxygen sparge significantly increases jet fuel thermal oxidative degradation. Second, a model compound experiment suggests SMORS precursors, phenol and 1,4-benzoquinone, are generated in situ from flask oxidation of a natural jet fuel component cumene (isopropylbezene) at 160 °C with an air sparge for 300 min. This observation is particularly significant for the thermal oxidative degradation of ultra-low sulfur diesel (ULSD) because it suggests that fuels with low heteroatom content may oxidatively degrade by the SMORS mechanism. Third, doping parts per million (ppm) levels of 2,4-dimethylpyrrole into oxidatively stable jet fuels followed by flask oxidation at 95 °C with an air sparge for 30 min results in significant oxidation of the jet fuels. This observation is particularly significant for the storage and thermal oxidative stability of Athabasca-tar-sands-derived middle distillates, which have previously been shown to contain alkylpyrroles; these middle distillates are predominate across the northern tier of the United States.

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Development of Oxygen Scavenger Additives for Future Jet Fuels. A Role for Electron-Transfer-Initiated Oxygenation (ETIO) of 1,2,5-Trimethylpyrrole?

Cited by 9 publications

References 24 publications

Gum Formation in Gasoline and Its Blends: A Review

Gum Formation in Gasoline and Its Blends: A Review

Modeling of Unwashed and Washed Gum Content in Brazilian Gasoline–Ethanol Blends during Prolonged Storage: Application of a Doehlert Matrix

Oxidative Stability of Middle Distillate Fuels. Part 1: Exploring the Soluble Macromolecular Oxidatively Reactive Species (SMORS) Mechanism with Jet Fuels

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