Straight-chain alkanes names

The molecule marked 12A is a seven-carbon straight-chain alkane named heptane. However, 12A is color coded in a peculiar manner such that a methyl group is attached to the end of a six-carbon linear chain. Can an alkyl substituent be added to the end of a linear chain Adding a methyl group in this fashion gives a seven-carbon unbranched chain, which is heptane, of course. Adding a methyl group to the end of a chain simply extends the linear chain. 

Number of carbon atoms Molecular formula of straight-chain alkane Name of alkane Stem used in naming... 

Straight-chain alkanes are named according to the number of carbon atoms they contain, as shown in Table 3.3. With the exception of the first four compounds—methane, ethane, propane, and butane—whose names have historical roots, the alkanes are named based on Greek numbers. The suffix -one is added to the end of each name to indicate that the molecule identified is an alkane. Thus, pentane is the five-carbon alkane, hexeme is the six-carbon alkane, and so on. We ll soon see that these alkane names form the basis for naming all other organic compounds, so at least the first ten should be memorized. 

The names of straight-chain alkanes are given in Table 18.1 they all end in -ane. Name a hydrocarbon side chain as a substituent by changing the ending -ane to -yl (as in the last two columns in Table 18.1). 

As the name hydrocarbon suggests, these partners may be hydrogen or carbon. The simplest of the alkanes, called continuous or straight-chain alkanes, consist of one straight chain of carbon atoms linked with single bonds. Hydrogen atoms fill all the remaining bonds. 

Other types of alkanes include closed circles and branched chains, but we discuss the straight-chain alkanes here because they make clecir the basic strategy for naming hydrocarbons. From the standpoint of nciming, the hydrogen atoms in a hydrocarbon are more or less filler atoms. Alkanes names cire based on the largest number of consecutively bonded carbon atoms, so the ncime of a hydrocarbon tells you about that molecule s structure. 

To name a straight-chain alkane, simply match the appropriate chemical prefix with the suffix -ane. The prefixes, which relate to the number of Ccirbons in the continuous chain, are listed in Table 64. 

You can refer to the same molecule in a number of different ways. For example, you can refer to pentane by its name (ahem. .. pentane)] by its molecular formula, CjHj2 or by the complete structure in Figure 6-2. Clearly, these names include different levels of structural detail. A condensed structural formula is another naming method, one that straddles the divide between a molecular formula and a complete structure. For pentane, the condensed structural formula is CH3CH2CH2CH2CH3. This kind of formula assumes that you understand how straight-chain alkanes are put together. Here s the lowdown ... 

To names simple alkanes the longest carbon chain is selected. The names of the simplest straight chain alkanes are shown in the following figure ... 

Steps 1 and 2 are all that are needed to name unbranched alkanes. For example, the straight-chain alkane with seven carbons is heptane. 

Recall that carbon can bond to form long, continuous, chain-like structures. Alkanes that bond in this way are called straight-chain alkanes. (They are also called unbranched alkanes.) Straight-chain alkanes are the simplest alkanes. Table 13.2 lists the names of the first ten straight-chain alkanes. 

The naming rules for straight-chain alkanes can, with a few additions, help you recognize and name other organic compounds. You now know that the name of a straight-chain alkane is composed of a root (such as meth-) plus a suffix (-ane). Earlier in the chapter, you saw the isomers of C6Hi4. Figure 13.13 shows one of them, called 2-methylpentane. 

Straight-chain alkanes are named according to the number of carbons in their chain. 

Straight chain alkanes take n- in the front of name, which means "normal" and shows the alkane is unbranched. 

For example, the names of all alkanes end with the suffix -ane. The simplest alkane is methane, CH4, the main component of natural gas. Table 3 lists the names and formulas for the first 10 straight-chain alkanes. For alkanes that consist of five or more carbon atoms, the prefix comes from a Latin word that indicates the number of carbon atoms in the chain. 

Each alkane-based substituent group branching from the parent chain is named for the straight-chain alkane having the same number of carbon atoms as the substituent. The ending -ane is replaced with the letters -yl, as shown in the following diagram. 

Count the number of carbon atoms in the longest continuous chain. Use the name of the straight-chain alkane with that number of carbons as the name of the parent chain of the structure. 

Table 3.3 Names of Straight-Chain Alkanes Number of carbons (/ ) Name...

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