Petroleum hydrocarbons alkanes

Whyte LG, L Bourbonniere, CW Greer (1997) Biodegradation of petroleum hydrocarbons by psychotrophic Pseudomonas strains possessing both alkane (alk) and naphthalene (nah) catabolic pathways. Appl Environ Microbiol 63 3719-3723. 

Yang et al. [2] have compared sorbent trapping with solvent trapping after the supercritical fluid extraction of volatile petroleum hydrocarbons in soil. Sorbent trapping yielded quantitative collections of n-alkanes as volatile as n-hexane, while solvent trapping effectively collected w-alkanes as volatile as n-octane. 

Several methodologies can be used to identify not only crude or refined product type, but also the brand, grade, and, in some instances, the source crude. The petroleum industry has yielded conventional methods for the characterization of refined products. The simplest is the routine determination of API gravity and development of distillation curves where NAPL is present. More sophisticated methods include gas chromatography and statistical comparisons of the distribution of paraffinic or n-alkane compounds between certain C-ranges. With increased degradation and decomposition, the straight-chain hydrocarbons ( -alkanes) become less... 

The petroleum-based oils contain hundreds to thousands of hydrocarbon compounds, including a substantial fraction of nitrogen- and sulfur-containing compounds. The hydrocarbons are mainly mixtures of snaight- and branched-chain hydrocarbons (alkanes), cycloalkanes, and aromatic hydrocarbons. Polynuclear aromatic hydrocarbons, alkyl polynuclear aromatic hydrocarbons, and metals are important components of motor oils and crankcase oils, with the used oils... 

The major petroleum resources contain linear, saturated hydrocarbons (alkanes), cyclic alkanes, and aromatics. For the most part, this material is considered to have low free-energy content. 

Aliphatic hydrocarbons such as n-alkanes and n-alkenes have been successfully used to distinguish between algal, bacterial, and terrestrial sources of carbon in estuarine/coastal systems, and also anthropogenic fossil sources (e.g., petroleum hydrocarbons). 

Benzene can also be produced from petroleum hydrocarbons by aromatization. Alkanes can be dehydrogenated to produce benzene and its derivatives by heating them over catalysts. 

Aliphatic hydrocarbons include straight chain and branched structures. Industrial solvents, petroleum hydrocarbons, and the linear alkyl benzene sulfonates (LAS) are the primary sources of aliphatic hydrocarbon pollutants. Many microorganisms utilize aliphatic hydrocarbons as carbon sources. Long-chain -alkanes are utilized more slowly due to the low bioavailability that results from their extremely low solubility in water. In contrast, short-chain rc-alkanes show a higher aqueous solubility. 

Accumulation of point sources from land use of petroleum products also can affect surface waters. For example, urban riverine inputs of volatile hydrocarbons to the marine environment have been studied in the coastal waters of Spain by Gomez-Belinchon et al. (1991). Volatile petroleum hydrocarbon inputs from two rivers were found to account for a mass flux of 47tyr and 96tyr of alkylbenzenes and 38tyr and 66 tyr of w-alkanes each. Although this was a significant mass flux, the... 

Chemical/Phamaceutical/Other Class Petroleum hydrocarbon mixture of branched-chain alkanes, cycloalkanes, aromatic compounds, and sulfuri-zed esters... 

Scope of the Problem. Petroleum hydrocarbons are the principal components in a wide variety of commercial products (e.g., gasoline, fuel oils, lubricating oils, solvents, mineral spirits, mineral oils, and crude oil). Because of widespread use, disposal, and spills, environmental contamination is relatively common. It is important to understand that petroleum products are complex mixtures, typically containing hundreds of compounds. These include various amounts of aliphatic compounds (straight-chain, branched-chain, and cyclic alkanes and alkenes) and aromatic compounds (benzene and alkyl benzenes, naphthalenes, and PAHs). In addition, many petroleum products contain nonhydrocarbon additives such as alcohols, ethers, metals, and other chemicals that may affect the toxicity of the mixture. 

Noncarcinogenic Effects. These effects are assessed only if the carcinogenic indicator compounds are not detected or are below regulatory criteria. The following petroleum hydrocarbon fractions, minus the carcinogenic indicator compounds, were selected as representing compounds with similar transport properties. Toxicity values for constituents of the fraction or for a similar mixture were selected to represent the toxicity of the fraction. Aromatic and aliphatic hydrocarbons are considered separately and further subdivided on the basis of equivalent carbon number index (EC). This index is equivalent to the retention time of the compounds on a boiling point GC column (non-polar capillary column), normalized to the //-alkanes. Physical and chemical properties of hydrocarbons that are... 

It is important to note that there are specific bacteria-contaminant combinations that will be the exceptions to the trend. In addition, this list does not include the impact of bioavailability or concentration. For instance, normal alkanes are considered the most biodegradable of all petroleum hydrocarbons. However, at elevated concentrations the C5-C10 compounds inhibit the activity of several hydrocarbon degraders.Furthermore, the number, type, and position of substitutions will also influence the ease of degradation in branched chains, aromatics, and multiple ringed compounds. As the complexity of the compound s structure and the number of compounds present at a site increase, one microbial strain will... 

The azeotrope formation between sulfur compounds, thiols, alkane disulfides, and thiophenes, and petroleum hydrocarbons have been extensively studied by the Anglo-Iranian Oil Co. the results have been published in several papers (87, 88). Research workers of this company have also secured data on vapor-temperature relationships of sulfur compounds (110). 

The objective of the process is to convert saturated hydrocarbons (alkanes and cycloalkanes) in petroleum naphtha fractions to aromatic hydrocarbons as selectively as possible, since the latter have excellent antiknock ratings (1,2). Naphtha fractions are composed of hydrocarbons with boiling points in the approximate range of 50-200°C. Reaction temperatures of 425-525°C and pressures of 10-35 atm are employed in the process. Reforming catalysts commonly contain platinum (3-5) or a combination of platinum and a second metallic element such as rhenium (6) or iridium (2,7). 

Generally, the type and identity of fresh to mildly weathered oils and petroleum products can be readily revealed from their GC-FlD traces, especially where the spilled oil or petroleum product is heavy and background hydrocarbon levels are low in an impacted environment. In addition to measuring TPH and other hydrocarbon groups in samples, GC-FID chromatograms provide a distribution pattern of petroleum hydrocarbons (e.g., carbon range and profile of UCM), fingerprints of the major oil components (e.g., individual resolved n-alkanes and major isoprenoids), and... 

See particularly Eglopp and Hulla, Alkylation of Alkanes, vol. I, Reinhold Publishing Corporation, New York, 1948 Brooks et al., The Chemistry of Petroleum Hydrocarbons, especially chaps. 54 and 57, Reinhold Publishing Corporation, New York, 1966. 

---