CHAPTER TWO Alkanes TABLE 2.4 IUPAC Names of Unbranched Alkanes Number Number Number of carbon of carbon Name of carbon Name Methane Undecane Henicosane Ethane 123456789 Dodecane 1234012 Docosane 23456 3 Propane Tridecane Tricosane Butane Tetradecane Tetracosane Pentane Pentadecane Triacontane Hexane Hexadecane Hentriacontane Heptane Heptadecane Dotriacontane 8 Octane Octadecane Tetracontane Nonane Nonadecane 60 Pentacontane Decane Icosane 100 Hectare Spelled"eicosane"prior to 1979 version of IUPAC rules. (c)What is the IUPAC name of the alkane described in Problem 2.3 as a compo- nent of the cockroach aggregation pheromone? SAMPLE SoLUTION(a) Note in Table 2.4 that hentriacontane has 31 carbon atoms. All the alkanes in Table 2,4 have unbranched carbon chains. Hentriacon tane has the condensed structural formula CH3(CH2)29CH3 In Problem 2. 4 you were asked to write structural formulas for the five alkanes of molecular formula C6Hi4. In the next section you will see how the IUPAC rules generate a unique name for each isomer 2.9 APPLYING THE IUPAC RULES: THE NAMES OF THE C6H14 ISOMERS We can present and illustrate the most important of the IUPAC rules for alkane nomen You might find it helpful clature by naming the five C6Hi4 isomers. By definition (Table 2.4), the unbranc C6H14 isomer is the ChIa isomers CH3CH, CH,CH, CH,CH3 IUPAC name: hexane The IUPAC rules name branched alkanes as substituted derivatives of the unbranched alkanes listed in Table 2. 4. Consider the C6H14 isomer represented by the structure CH3CHCH, CH,CH Step I Pick out the longest continuous carbon chain, and find the IupAc name in Table 2.4 that corresponds to the unbranched alkane having that number of carbons. This is the parent alkane from which the IUPAC name is to be derived. Back Forward Main MenuToc Study Guide ToC Student o MHHE Website62 CHAPTER TWO Alkanes (c) What is the IUPAC name of the alkane described in Problem 2.3 as a compo￾nent of the cockroach aggregation pheromone? SAMPLE SOLUTION (a) Note in Table 2.4 that hentriacontane has 31 carbon atoms. All the alkanes in Table 2.4 have unbranched carbon chains. Hentriacon￾tane has the condensed structural formula CH3(CH2)29CH3. In Problem 2.4 you were asked to write structural formulas for the five isomeric alkanes of molecular formula C6H14. In the next section you will see how the IUPAC rules generate a unique name for each isomer. 2.9 APPLYING THE IUPAC RULES: THE NAMES OF THE C6H14 ISOMERS We can present and illustrate the most important of the IUPAC rules for alkane nomen￾clature by naming the five C6H14 isomers. By definition (Table 2.4), the unbranched C6H14 isomer is hexane. The IUPAC rules name branched alkanes as substituted derivatives of the unbranched alkanes listed in Table 2.4. Consider the C6H14 isomer represented by the structure Step 1 Pick out the longest continuous carbon chain, and find the IUPAC name in Table 2.4 that corresponds to the unbranched alkane having that number of carbons. This is the parent alkane from which the IUPAC name is to be derived. CH3CHCH2CH2CH3 W CH3 CH3CH2CH2CH2CH2CH3 IUPAC name: hexane (common name: n-hexane) TABLE 2.4 IUPAC Names of Unbranched Alkanes Number of carbon atoms 1 2 3 4 5 6 7 8 9 10 Name Methane Ethane Propane Butane Pentane Hexane Heptane Octane Nonane Decane Name Undecane Dodecane Tridecane Tetradecane Pentadecane Hexadecane Heptadecane Octadecane Nonadecane Icosane* Number of carbon atoms 11 12 13 14 15 16 17 18 19 20 Name Henicosane Docosane Tricosane Tetracosane Triacontane Hentriacontane Dotriacontane Tetracontane Pentacontane Hectane Number of carbon atoms 21 22 23 24 30 31 32 40 50 100 *Spelled “eicosane” prior to 1979 version of IUPAC rules. You might find it helpful to make molecular models of all the C6H14 isomers. Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website