Diesel fuel alkanes

Diesel fuel is produced by distilling raw oil, which is extracted from bedrock. Diesel is a fossil fuel, consisting of hydrocarbons with between 9 and 27 carbon atoms in a chain, as well as a smaller amount of sulfur, nitrogen, oxygen and metal compounds. It is a general properly of hydrocarbons that the autoignition temperature is higher for more volatile hydrocaibons. The hydrocarbons present in the diesel fuels include alkanes, naphthenes, olefins and aromatics. 

The age of diesel oil in the subsurface soil environment can be determined by utilizing the fact that the composition of the diesel oil (the ratio between -alkanes and isoprenoids) changes due to biodegradation. In one study, the ratio of C , to pristane was highly correlated with the residence time of diesel fuel at 12 test locations (Christensen et al 1993). 

Alkanes undergo combustion reaction with oxygen at high temperatures to produce carbon dioxide and water. This is why alkanes are good fuels. Oxidation of saturated hydrocarbons is the basis for their use as energy sources for heat, e.g. natural gas, liquefied petroleum gas (LPG) and fuel oil, and for power, e.g. gasoline, diesel fuel and aviation fuel. 

The method of analysis involves extraction of 1 L of aqueous sample (liquid-liquid extraction) or 25 g of soil (sonication or Soxhlett extraction or supercritical fluid extraction) or an appropriate amount of the sample with methylene chloride. The extract is dried, concentrated to a volume of 1 mL, and injected into a capillary GC column for separation and detection by FID. For quantitation, the area or height response of all peaks eluting between C-10 and C-28 are summed and compared against the chromatographic response of the same peaks in a 2 Fuel or Diesel Oil standard. A 10-component n-alkanes mixture containing even numbered alkanes ranging between 10 and 28 C atoms has been recommended as an alternative calibration standard. These alkanes occur in all types of diesel oils, and each compound constitutes approximately a 1% total mass of diesel fuel, i.e., 1 g of diesel fuel contains about 10 mg each of any of the above alkanes. Therefore, when using the latter as a calibration standard, the result must be multiplied appropriately by 100. 

As mentioned earlier, if a 10-component alkane mixture is used as standard, the result obtained from IS or extraction standard calibration must be multiplied by 100 because each alkane constitutes about 1% mass of diesel fuel. If a 2 fuel oil or a diesel oil standard is used instead of a 10-component alkane mixture, and when all the major peaks in the sample extract and standards are taken into consideration, then the result must not be multiplied by 100. 

Cg—C16 The nonanes (C9) through about the hexadecanes (C19) are higher-boiling liquids that are somewhat viscous. These alkanes are used in kerosene, jet fuel, and diesel fuel. Kerosene, the lowest-boiling of these fuels, was once widely available but is now harder to find. It is less volatile than gasoline and less prone to forming explosive mixtures. Kerosene was used in kerosene lamps and heaters, which use wicks to allow this heavier fuel to burn. Jet fuel is similar to kerosene, but more highly refined and less odorous. 

All diesel fuels eventually cause start-up and operability problems when subjected to sufficiently low temperatures. As the ambient temperature cools, high-molecular weight paraffins present in petrodiesel nucleate and form solid wax crystals which, suspended in liquid, are composed of short-chain n-alkanes and aromatics (Chandler et al., 1992 Owen and Coley, 1990 Lewtas et al., 1991 Brown et al., 1989 Zielinski and Rossi, 1984). Left unattended overnight... 

Though FAME has limited oxidation stability, they remain a valid alternative for diesel. Conventional diesel fuel has a boiling range of 180-340 °C, with a composition of n-alkanes, cycloalkanes, alkyl benzenes, and polyaromatic compounds. Fossil diesels have a CN in the range 40-100. FAME has properties that are close to all these basic diesel properties. FAME can also easily blend with fossil diesel at any level due to their similar solvent behavior the viscosity of fossil diesel and biodiesel are also in the same range. 

LP mordenite doped with platinum is the catalyst used in the Shell Hysomer process for alkane hydroisomerization this can be linked to the Isosiv separation process whereby -/n-alkanes are separated on LTA zeolite. This link is the basis of the joint Shell/UOP Total Isomerization Process (TIP). Similar catalysts have been employed to hydrocrack (i.e. dewax) diesel fuels. There have also been reports of commercial use of mordenite to catalyze methanol amination with ammonia, to produce dimethylamine. 

Alkanes, the simplest hydrocarbons, are found in ail shapes and sizes and occur widely in nature. They are the major constituents of petroleum, a complex mixture of compounds that includes hydrocarbons such as hexane and decane. Petroleum is refined to produce gasoline, diesel fuel, home heating oil, and a myriad of other useful compounds. In Chapter 4, we learn about the properties of alkanes, how to name them (nomenclature), and oxidation—one of their important reactions. 

Alkanes, the major constituents of petroleum, which is refined to produce gasoline, diesel fuel, and home heating oil (Opener, Section 4.7)... 

The test results show that n-paraffin (1) linearly raises the cetane of unadditized diesel without a top-end limit (2) can linearly raise the cetane of nonresponsive diesel blends (3) is synergistic with traditional cetane improvers (4) has a low sulfur content and (5) increases endproduct volume added (4, 5). When n-alkanes and cetane enhancers were added to a diesel fuel with a cetane number of 32 to raise the cetane number to 43, a 10% reduction in carbon dioxide emissions was achieved. 

Diesel fuel no. 1 is a straight-run middle distillate with a boiling range consistent with that of kerosene. It contains branched-chain alkanes (paraffins), cycloalkanes (naphthenes), aromatics, and mixed aromatic... 

The alkanes, cycloalkanes, and aromatic compounds present in diesel are lipophilic and tend to distribute to tissues with higher adipose tissue content. The reversibility and short-term nature of many effects observed during acute exposure indicate that retention of the principal diesel fuel components in body tissues is limited. 

The alkanes and cycloalkanes in diesel fuel are generally not readily metabolized, and are mostly excreted unchanged through the lungs, with a very small fraction excreted in the urine. The aromatic constituents of diesel are subject to oxidative metabolism and are typically excreted in the urine as water-soluble metabolites. 

Hydrocarbon fuels are complex mixtures of more than 250 different molecular species. Compounds contained in such fuels include benzene, toluene, xylene, various alkyl benzenes, naphthalene, hexanes, heptanes, octanes, and higher molecular weight alkanes, all of which are neurotoxic. Fuel additives further complicate the mixtures. Acute and chronic exposures to low levels of hydrocarbon fuels, including gasoline, kerosene, diesel fuel, and jet fuel result in neurotoxic and neurobehavioral effects that are at times seemingly different from those anticipated from exposure to the individual chemicalsJ105l... 

Fuel oil 2 is characterized by hydrocarbon chain lengths in the Cn-C20 range, whereas diesel fuels predominantly contain a mixture of C10-C19 hydrocarbons (ATSDR 1995g). The composition consists of approximately 64% aliphatic hydrocarbons (straight chain alkanes and cycloalkanes), 1-2% unsaturated hydrocarbons (alkenes), and 35% aromatic hydrocarbons (including alkylbenzenes and 2-, 3-ring aromatics) (Air Force 1989). Fuel oil 2 contains less than 5% polycyclic aromatic hydrocarbons (IARC 1989b). The typical hydrocarbon composition of fuel oil 2 is presented in Table E-4.b (Appendix E). 

Petroleum is a complex mixture, mostly of alkanes and cyclic alkanes. Products we get from petroleum include gasoline, jet fuel, kerosene, diesel fuel, fuel oil, asphalt, and lubricating oil. To use these organic products, they have to be separated from one another. What properties of hydrocarbons might allow them to be separated ... 

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