Oil, alkanes

Szafranek, J., Kusmierz, J. and Czerwiec, W. (1982). Gas chromatographic-mass spectrometric investigations of high-boiling crude oil alkane fractions. 

The latter values are approximately five times larger. This shows that the simple dependence of the hydrophobic effect on the number of carbon atoms becomes rather complicated when considering the interfacial properties. These differences thus may be suggestive of the differences in orientation of the aUcyl chains at the interfaces. This subject has been recently investigated by measuring surface tension and interfacial tension near the freezing point of the oil (alkanes) phase under supercooled measurements, as described further below. 

The efficiency of the carbon source conversion into pigments and the optimization of the growth medium with respect to its availability and price have been the subject of intensive studies. Niunerous sources, including pentoses and hexoses, various disaccharides, glycerol, ethanol, methanol, oils, -alkanes, or a wide variety of wastes derived from agricultural production (e.g., molasses, bananas, starch wastes. 

Willhelms a., Larter S. R. and Hall K. (1994) A comparative study of the stable carbon isotopic composition of crude oil alkanes and associated cmde oil asphaltene pyrolysate alkanes. Org. Geochem. 21, 751-759. 

Yeast and bacteria can produce biosurfactants, biological surfactants from various substrates including sugars, oils, alkanes and wastes [5]. Some types of biosurfactants are glycolipids, lipopeptides, phospholipids, fatty acids, neutral lipids, polymeric and particulate compounds [6]. Most are either anionic or neutral, while only a few with amine groups are cationic. The hydrophobic part of the molecule is based on long-chain fatty acids, hydroxy fatty acids or a-alkyl-jS-hydroxy fatty acids. The hydrophilic portion can be a carbohydrate, amino acid, cyclic peptide, phosphate, carboxylic acid or alcohol. 

The procedure should also specify the temperature at which the mixing and separation takes place, the amount of time that must elapse before asphaltenes are separated from the oil/alkane mixture, and even the method used to accomplish the separation (filter size. 

Scanned Formulation Variable is the Oil Alkane Carbon Number ACN... 

Alkanes are solvents for nonpolar organic materials such as fats and oils. Alkane vapors, such as those of gasoline, cause severe damage to lung tissue by dissolving the fatty material in cell membranes. Body oils maintain the moisture of human skin. Long-term contact between low-molecular-weight alkanes and skin removes skin oils and can cause soreness and blisters. For this reason, contact with alkane solvents such as paint thinner or paint remover should be avoided. 

Solvent deasphalting. This is an extraction of the heaviest fractions of a vacuum residue or heavy distillate. The extract is used to produce the bitumen. The separation is based on the precipitation of asphaltenes and the dissolution of the oil in an alkane solvent. The solvents employed are butane or propane or a butane-propane mixture. By selecting the proper feedstock and by controlling the deasphalting parameters, notably temperature and pressure, it is possible to obtain different grades of bitumen by this process. 

Alkanes from CH to C4gFlg2 typically appear in crude oil, and represent up to 20% of the oil by volume. The alkanes are largely chemically inert (hence the name paraffins, meaning little affinity), owing to the fact that the carbon bonds are fully saturated and therefore cannot be broken to form new bonds with other atoms. This probably explains why they remain unchanged over long periods of geological time, despite their exposure to elevated temperatures and pressures. 

Olefins are uncommon in crude oils due to the high chemical activity of these compounds which causes them to become saturated with hydrogen. Similarly, acetylene is virtually absent from crude oil, which tends to contain a large proportion of the saturated hydrocarbons, such as the alkanes. 

There are a total of eighteen different hydrocarbon series, of which the most common constituents of crude oil have been presented - the alkanes, cycloalkanes, and the arenes. The more recent classifications of hydrocarbons are based on a division of the hydrocarbons in three main groups alkanes, naphthanes and aromatics, along with the organic compounds containing the non-hydrocarbon atoms of sulphur, nitrogen and oxygen. 

Solubility in Water A familiar physical property of alkanes is contained m the adage oil and water don t mix Alkanes—indeed all hydrocarbons—are virtually insoluble m water In order for a hydrocarbon to dissolve m water the framework of hydrogen bonds between water molecules would become more ordered m the region around each mole cule of the dissolved hydrocarbon This increase m order which corresponds to a decrease m entropy signals a process that can be favorable only if it is reasonably... 

Pnstane is an alkane that is present to the extent of about 14% in shark liver oil Its lUPAC name is 2 6 10 14 tetramethylpentadecane Write its structural formula... 

Hydrocarbons, compounds of carbon and hydrogen, are stmcturally classified as aromatic and aliphatic the latter includes alkanes (paraffins), alkenes (olefins), alkynes (acetylenes), and cycloparaffins. An example of a low molecular weight paraffin is methane [74-82-8], of an olefin, ethylene [74-85-1], of a cycloparaffin, cyclopentane [287-92-3], and of an aromatic, benzene [71-43-2]. Cmde petroleum oils [8002-05-9], which span a range of molecular weights of these compounds, excluding the very reactive olefins, have been classified according to their content as paraffinic, cycloparaffinic (naphthenic), or aromatic. The hydrocarbon class of terpenes is not discussed here. Terpenes, such as turpentine [8006-64-2] are found widely distributed in plants, and consist of repeating isoprene [78-79-5] units (see Isoprene Terpenoids). 

The butane-containing streams in petroleum refineries come from a variety of different process units consequently, varying amounts of butanes in mixtures containing other light alkanes and alkenes are obtained. The most common recovery techniques for these streams are lean oil absorption and fractionation. A typical scheme involves feeding the light hydrocarbon stream to an absorber-stripper where methane is separated from the other hydrocarbons. The heavier fraction is then debutanized, depropanized, and de-ethanized by distillation to produce C, C, and C2 streams, respectively. Most often the stream contains butylenes and other unsaturates which must be removed by additional separation techniques if pure butanes are desired. 

Within the VGO saturates, distribution of paraffins, isoparaffins, and naphthenes is highly dependent on the petroleum source. The naphthenes account for roughly 60% of the saturates in a normal cmde oil. However, samples can be found having paraffins from <20 to >80%. In most samples, the / -paraffins from C2Q—are still present in sufficient quantity to be detected as distinct peaks in gc analyses. Some cmde oils show a nearly symmetric pattern of peaks such that each carbon number is present in regular progression up to a maximum around C -j. Other cmde oils show a similar distribution, but have preference for odd-numbered alkanes. Both the distribution and the selectivity toward odd-numbered hydrocarbons are considered to reflect differences in petrogenesis of the cmde oils. Although / -paraffins are distinct in the gc, these usually account for only a few percent of the saturates measured by gc. 

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