sobutyl Groups H H H H-C-C-C-H H—C—C—C-H HH H HHH ISO butyl tert-butyl A primary carbon a tertiary carbon Chapter 3
Chapter 3 11 Isobutyl Groups H C H H C C H H C H H H H H C H H C C H H C H H H H H H A primary carbon A tertiary carbon => isobutyl tert-butyl
Alphabetize Alphabetize substituents by name Ignore di-, tri-, etc for alphabetizing CH3 CH3 H3C--CH-CH-CH2--CH2--CH-CH3 CH2CH3 3-ethyl-2, 6-dimethylheptane Chapter 3 12
Chapter 3 12 Alphabetize • Alphabetize substituents by name. • Ignore di-, tri-, etc. for alphabetizing. H3 C CH CH3 CH CH2 CH3 CH2 CH2 CH CH3 CH3 3-ethyl-2,6-dimethylheptane =>
CompleX Substituents If the branch has a branch number the carbons from the point of attachment Name the branch off the branch using a locator number Parentheses are used around the complex branch name 1-methyl-3(1, 2-dimethylpropyl)cyclohexane = Chapter 3 13
Chapter 3 13 Complex Substituents • If the branch has a branch, number the carbons from the point of attachment. • Name the branch off the branch using a locator number. • Parentheses are used around the complex branch name. 1 2 3 1-methyl-3-(1,2-dimethylpropyl)cyclohexane =>
Physical Properties Solubility: hydrophobic Density: less than 1 g/mL Boiling points increase with increasing carbons (little less for branched chains) Melting points increase with increasing carbons(less for odd number of carbons) Chapter 3 14
Chapter 3 14 Physical Properties • Solubility: hydrophobic • Density: less than 1 g/mL • Boiling points increase with increasing carbons (little less for branched chains). Melting points increase with increasing carbons (less for oddnumber of carbons). •
Boiling points of Alkanes Branched alkanes have less surface area contact so weaker intermolecular forces 400 CH3(CH2)nCH 200 n-alkanes 三c月 8100 CH3 CH—(CH2)2CH 100 soalkanes CH > 200 10 15 number of carbon atoms Chapter 3
Chapter 3 15 Boiling Points of Alkanes Branched alkanes have less surface area contact, so weaker intermolecular forces. =>