Acyclic alkanes normal

Normal alkane (Section 4.1 A) An acyclic alkane that has all of its carbons in a row. A normal alkane is an -alkane or a straight-chain alkane. 

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 ... 

Acyclic isoprenoidal alkanes may be important constituents, particularly pristane (2,6,10,14-tetra-methylpentadecane) and phytane (2,6,10,14-tetra-methylhexadecane) (Fig. 4.23a). Unfortunately, the term isoalkane is sometimes used to describe all the branched alkanes and not just the 2-methylalkanes. Acyclic alkanes normal surface conditions, while those up to C15 are liquids. The n-alkanes with >15 C atoms tend to be viscous liquids grading into solid waxes (the transition depending upon the ambient temperature). 

There is a nomenclature dilemma for cyclic alkanes. The suffix for the name must be ane because they are alkanes. The normal prefix will indicate the presence of 3-12 carbons for the alkanes in Figure 4.4, so the names should be propane to dodecane. Those names have already been taken for the acyclic alkanes To distinguish between the linear 12-carbon molecule (dodecane) and the 12-membered cyclic (ring) alkane, use the term cyclo. If the ring is viewed as a cycle, then the prefix cyclo is used in front of the alkane name (a prefix in front of the carbon number prefix). The three-membered ring alkane therefore becomes cyclopropane and the 12-membered ring alkane becomes cyclododecane (see Figure 4.4). 

Gas chromatography (G.C.) by packed and capillary column then enables individual normal (homologous series) and acyclic iso-prenoid alkanes to be identified from, in the present work, coal tars and Turkish lignite, wax and asphaltites (and also petroleum crudes). 

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