The Naming Conventions for Alkanes

In general, the stem of the name tells you the number of carbon atoms (meth = 1, eth = 2, prop = 3, but = 4, and so on), and the suffix ane tells you that the molecule is an alkane. The alkane name is sometimes called the root word. The names of some straight-chain alkanes are collected in Table 2.4. 

It will be important to know how to interpret the lUPAC names, because 

FIGURE 2.39 Rnding the longest straight chain of carbons in alkanes. 

In a substituted alkane, the substituent is given a number based on its position in the parent hydrocarbon. The longest chain is numbered so as to make the number of the substituent position as low as possible. The substituent is listed as a prefix to the root word, with the number indicating its location on the chain. Some examples are shown in Rgure 2.40. In a polysubstituted alkane, all the substituents receive numbers. The longest chain is numbered so that the lowest possible numbers are used. A useful trick is to number the chain from the end closest to the first substituent or branch point. 

When there are multiple substituents, they are always ordered alphabetically in the prefix (Fig. 2.41). If the multiple substituents are identical, then di-, tri-, tetra-, and 

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Names. In truth, it is not necessary to know every nuanced detail of the naming convention for alkanes, but you do need to know some nomenclature. 

The naming convention for alkanes is introduced. There are several common or trivial names that are often used and which, therefore, must be learned. 

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