Melting Points of Alkanes Branched alkanes pack more efficiently into a crystalline structure, so have higher m p 50 even numbers -50 8 ep-100 odd numbers 150 200 10 15 20 number of carbon atoms Chapter 3 16
Chapter 3 16 Melting Points of Alkanes Branched alkanes pack more efficiently into a crystalline structure, so have higher m.p. =>
Branched alkanes Lower b.p. with increased branching Higher m p with increased branching Examples: CH3 CH3CCH,CH CHIs--CH-CH2-CH2-CH3 C13 CH--CH-CH3 CH CH CH3 CH bp60°C p bp58°C p50°C mp-154°C mp-135°C mp-98°C hapter 3 17
Chapter 3 17 Branched Alkanes • Lower b.p. with increased branching • Higher m.p. with increased branching • Examples: H CH3 CH CH3 CH2 CH2 CH3 bp 60°C mp -154°C CH3 CH CH3 CH CH3 CH3 bp 58°C mp -135°C => bp 50°C mp -98°C CH3 C C 3 CH3 CH2 CH3
Major Uses of alkanes C1-C2: gases(natural gas C3-C4: liquified petroleum (LPG) 5-C8:gasoline Cg-C16: diesel, kerosene, jet fuel C1r-up: lubricating oils, heating oil Origin: petroleum refining hapter 3 18
Chapter 3 18 Major Uses of Alkanes • C1 -C2 : gases (natural gas) • C3 -C4 : liquified petroleum (LPG) • C5 -C8 : gasoline • C9 -C16: diesel, kerosene, jet fuel • C17-up: lubricating oils, heating oil • Origin: petroleum refining =>