Role of indoles in the oxidative degradation of unstable diesel fuels. The ferric and cupric ion catalyzed oxidation of 1,2,3,4-tetrahydrocarbazole as a model compound study

Beaver, Bruce; Gilmore, Cristen; Veloski, Garret; Sharief, Vaqar

doi:10.1021/ef00026a009

Cited by 10 publications

(11 citation statements)

References 1 publication

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have previously proposed that electron-rich aromatic molecules such as pyrroles, 11,12 indoles, 13 and carbazoles can be thermally promoted to react directly with molecular oxygen. [14][15][16] It is conceivable that such chemistry could ultimately lead to production of a high concentration of peroxyl radicals.…”

Section: Resultsmentioning

confidence: 99%

Insight into the Mechanisms of Middle Distillate Fuel Oxidative Degradation. Part 2: On the Relationship between Jet Fuel Thermal Oxidative Deposit, Soluble Macromolecular Oxidatively Reactive Species, and Smoke Point

et al. 2009

Self Cite

View full text Add to dashboard Cite

We present data that suggest that jet fuel smoke point and the formation of thermal oxidative deposit are linked by formation of a common intermediate, high molecular weight soluble macromolecular oxidatively reactive species (SMORS). Hardy and Wechter (Energy Fuels 1994, 8, 782-787) have previously observed that with diesel fuels containing unhydrotreated light cycle oil (LCO), the highest molecular weight fraction of SMORS can be conveniently quantified as an extraction-induced precipitate (EIP). These authors have also shown that for fresh diesel fuel, oxidatively stressed fuel EIP mass correlates well with results of accelerated storage stability determined by ASTM 5304. Consistent with this, data are presented that suggest EIP mass, from jet fuels oxidatively stressed in tubing bombs, correlates with mean thermal oxidative deposition in a flowing reactor. In addition, data are presented that suggest that for a polar compound doped oxidatively stressed jet fuel, EIP mass correlates with the total concentration of polar compounds doped into the fuel. Thus, for the first time the concentration of select polar aromatics has been directly linked with the formation of a deposit precursor (Energy Fuels 1994, 8, 782-787) and smoke point.

show abstract

Section: Resultsmentioning

confidence: 99%

Insight into the Mechanisms of Middle Distillate Fuel Oxidative Degradation. Part 2: On the Relationship between Jet Fuel Thermal Oxidative Deposit, Soluble Macromolecular Oxidatively Reactive Species, and Smoke Point

et al. 2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…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

View full text Add to dashboard Cite

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.

show abstract

“…With reference to earlier studies, − ,− it can be speculated that the formation process of the gum in the F–T synthetic crude is as follows. Nonalkaline nitrogen compounds in the system form peroxides when exposed to air, which in turn generates free radicals.…”

Section: Resultsmentioning

confidence: 81%

“…When Sobkowiak et al 42 studied the role of phenol, indole, and carbazole derivatives in the thermal oxidation stability of the F–T mixed fuels, they found that the indole/carbazole structure exists in the diesel deposit precursor. Beaver et al 43 found that alkyl indole compounds are involved in the formation of insolubles and color during storage in diesel environments containing light cycle oil. Beaver et al 44 found that the catalytic cracking light cycle oil containing alkylphenol is harmful to the storage stability of the fuel.…”

Section: Resultsmentioning

confidence: 99%

Structure Characterization and Solubility Analysis of the Existent Gum of the Fischer–Tropsch Synthetic Crude

et al. 2020

View full text Add to dashboard Cite

The existent gum content of the Fisher–Tropsch synthetic crude exceeded the standard seriously, affecting its transportation and use. To determine the structure of the existent gum extracted from the Fisher–Tropsch synthetic crude, elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS) were employed to determine the chemical structure of the gum. The Brown–Ladner method is used to calculate the average structural parameters and the average molecular formula of the existent gum. The results show that the existent gum of the Fisher–Tropsch synthetic crude is composed of heterocyclic aromatic hydrocarbons and short-carbon paraffins. Compared with petroleum gums and coal tar gums, the existent gum content of the Fisher–Tropsch synthetic crude has the characteristics of high aromaticity, short side chains, and nitrogen-containing heterocycles. After being oxidized, its aromaticity further increases, more closed loops are formed, and the side chain is further shortened. This is caused by a complex oxidation reaction during the oxidation process. Molecular dynamics simulation calculations were performed to reveal the T-stacked morphology of the existent gum of the Fisher–Tropsch synthetic crude in a mixed solvent of acetone and toluene.

show abstract

Role of indoles in the oxidative degradation of unstable diesel fuels. The ferric and cupric ion catalyzed oxidation of 1,2,3,4-tetrahydrocarbazole as a model compound study

Cited by 10 publications

References 1 publication

Insight into the Mechanisms of Middle Distillate Fuel Oxidative Degradation. Part 2: On the Relationship between Jet Fuel Thermal Oxidative Deposit, Soluble Macromolecular Oxidatively Reactive Species, and Smoke Point

Insight into the Mechanisms of Middle Distillate Fuel Oxidative Degradation. Part 2: On the Relationship between Jet Fuel Thermal Oxidative Deposit, Soluble Macromolecular Oxidatively Reactive Species, and Smoke Point

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

Structure Characterization and Solubility Analysis of the Existent Gum of the Fischer–Tropsch Synthetic Crude

Contact Info

Product

Resources

About