Branched Alkanes Substituents Any hydrogen in a hydrocarbon

Branched Alkanes

Substituents • Any hydrogen in a hydrocarbon chain can be substituted with another hydrocarbon group

Substituents • The substituted hydrocarbon group is called an alkyl group • Suffix: -yl: hydrocarbon group

Branched Chains • When an alkane chain gets another hydrocarbon group substituted onto it • Branches: sidechains

Branched Chains C C C C C

Naming Branched Chains

Drill: Name Each: H 3 C-CH 2 -CH 3 C-C-C

1) Find the longest continuous carbon chain & name it as the main chain. The final name will end with the naming of the main chain

• C Hexane • C C C

2) Number each carbon in the chain; so that, the side chains will be connected to the lowest possible numbers on the carbons

• C Hexane 1 2 3 4 5 6 • C C C

3) Name the side chains or substituted groups, & precede them with the # of the carbon they are connected to & a dash

• C 2 -methyl 1 2 3 4 5 6 • C C C • 2 -methyl 4 -ethyl

4) If identical groups appear more than once, use prefixes: di for 2, tri for 3, tetra for 4, penta for 5, etc Examples: dimethyl, tripropyl, etc

• C 2, 2 -dimethyl 1 2 3 4 5 6 • C C C • 4 -ethyl

5) Name the sidechains or groups in alphabetical order, but ignore the prefixes when doing so · Examples: ethyl comes before dimethyl, e < m

6) Separate numbers with commas, use hyphens between words & numbers, and write the alkanes as one word · Example: dimethylhexane

• C C C C • 4 -ethyl-2, 2 -dimethylhexane

Name the organic compounds in problem 11 -5 on page 315

Name the organic compound on the board

Drill: Name CH 3 CH 2 H 3 C-CH-CH 2 -CH-CH-CH 3 CH 2 CH 3

Deriving Structures from Names • Draw the main chain first –Look the name ending • Draw the branches –Look the # & group name

Draw: • 3, 4 -diethyl-2 -methyloctane • 2, 3, 5 -trimethylhexane • 5 -butyl-3 -ethyl-2, 6, 8 trimethyl-4 -propyldecane

Drill: Draw: 5 -butyl-3 -ethyl-2, 6, 8, 9 -tetramethyl-4, 7 dipropyldecane

Isomers • Compounds that have the same chemical formula, but different shapes

Types of Isomers • Structural or skeletal • Geometric or cis/trans • Functional • Positional • Optical

Structural Isomers • When there are differences in the carbon chains

Structural Isomers C-C-C C C-C-C-C C

Draw & name all the possible structural isomers for C 7 H 16

Draw & name all the possible structural isomers for C 6 H 14

Drill: Name: C-C-C C C-C-C-C C C-C

Review

Identify • Organic terms • Organic prefixes • Organic suffixes

Drill: Name the organic compounds on the board:

Draw the organic compounds on the board:

Draw & Name isomers of: C 8 H 18