Hydrocarbons, classification normal

Additioneilly, "classes" or types of hydrocarbons were and still are determined based on the capability to isolate them by separation techniques. The four types usually sought eue paraffins, olefins, naphthenes, and aromatics. Paraffinic hydrocarbons include both normal and branched alkanes. Olefins refer to normal and branched alkenes that contain one or more double or triple carbon-carbon bonds. Naphthene (not to be confused with naphthalene ) is a term of the petroleum industry that refers to the saturated cyclic hydrocarbons or cycloalkanes. Finally, aromatics include all hydrocarbons containing one or more rings of the benzenoid structure. These general hydrocarbon classifications are complicated by many combinations of the above types, for example, olefinic aromatics (styrene) or alkylbenzenes (cumene). Table 4 presents a summary of the hydrocarbon types usually found in specific petroleum fractions. 

A paraffin wax is a petroleum wax consisting principally of normal alkanes. MicrocrystalHne wax is a petroleum wax containing substantial proportions of branched and cycHc saturated hydrocarbons, in addition to normal alkanes. SernimicrocrystaUine wax contains more branched and cycHc compounds than paraffin wax, but less than microcrystalHne. A classification system based on the refractive index of the wax and its congealing point as... 

The neo classification divides all benzenoids into normal (n), essentially disconnected (e) and non-Kekuleans (o), where the n and e systems cover all the Kekuleans. Cyvin and Gutman [26] have advocated for this classification by saying From the point of view of the enumeration of Kekule structures the classification. . . [neo]. . . seems to be a rather appropriate one [94,87] . However, the distinction between Kekulean (closed-shell, non-radicalic) and non-Kekulean (radicalic) benzenoid hydrocarbons was made long before the explicit definition of the neo classification. This practice started with the first (substantial) enumeration of benzenoids in the chemical context by Balaban and Harary [13]. 

Crude oils can be classified according to the relative amounts of acyclic alkanes, cycloalkanes and combined aromatic hydrocarbons plus NSO compounds present. This classification is represented by the ternary (triangular) plot in Fig. 4.22, and can be seen to distinguish between the main fields of marine and terrestrially sourced oils. The main classes of normal crudes resulting from this classification are ... 

Classification Petroleum distillate Definition Complex combination of hydrocarbons obtained as the raffinate from a solvent extraction process consists of predominantly Cl5-30 hydrocarbons contains relatively few normal paraffins... 

Later, Greenwald et al developed a classification system based on liquid-liquid distribution coefficients of surfactants in water and isooctane. In 1962, Huebner introduced a quantity called the polarity index (PI) intended to replace the HLB value." This index was found to have a linear relationship with the HLB value." The polarity index is determined from the carbon number corresponding to methanol, when methanol and normal hydrocarbons are separated on a gas chromatograph with the surfactant as... 

Synonyms Alkane C6 n-Hexane Hexyl hydride Normal hexane Classification Aliphatic hydrocarbon Empirical CgH,4 Formula CH3(CH2)4CH3... 

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