Alkane Nomenclature

in alkanes, all carbons are “saturated” (have four single bonds) Alkanes have the general formula CnH2n+2 This is the basis of all organic nomenclature

1. Find the longest continuous chain of carbons and name. # of carbons name 1 methane 2 ethane 3 propane 4 butane 5 pentane 6 hexane 7 heptane

8 octane 15 pentadecane 9 nonane 16 hexadecane 10 decane 17 heptadecane 11 undecane 18 octadecane 12 dodecane 19 nonadecane 13 tridecane 20 eicosane 14 tetradecane

2. Number the chain so that the branches have the lowest possible number. 3. Name and number each branching group (name with –yl ending)

Branching Groups methyl --CH3 ethyl --CH2—CH3 Propyl --CH2—CH2—CH3 l Isopropyl --CH3—CH—CH3 Butyl --CH2—CH2--CH2—CH3 Isobutyl CH3 --CH2—CH—CH3

secbutyl CH3—CH--CH2—CH3 Tertbutyl CH3—C—CH3 CH3

4. Alphabetize the groups. 5 If there is more than one group with the same name, use the appropriate prefix with the group name. 2 groups – di- 5 groups – penta- 3 groups – tri- 6 groups – hexa- 4 groups – tetra- 7 groups – hepta-

6. Punctuate Numbers are separated by commas Numbers are separated from words by hyphens 7. If a branching group chain consists of more than 4 carbons, the group is named as if it were a compound using the same rules (1-6), with the following exceptions: a. the chain must start at the branching carbon b. the name ends in –yl, not in –ane c. The group is enclosed in parentheses with its position # outside the parentheses d. Alphabetize the group by the 1st letter inside the parentheses.

8. If there are two chains of equal length, the chain with the greatest number of side chains is chosen as the main chain.