Constitutional Isomers of C2H6O
dimethyl ether
ethyl alcohol
• colorless gas
• clear liquid
• bp –25˚C
• bp 79˚C
• mp –138˚C
• mp –114˚C
• formerly used as an anesthetic
• active component in beer, wine…
• very unreactive, can be used as a • relatively reactive towards strong
solvent at low temperatures
bases, oxidants
CH3 O
CH3
CH3 CH2 OH
- or H
H C O
H
- or H
H H
C H
H C C
H
Notice valency (# of bonds)
H H
H, mono
O, di
C, tetra
O H
Alkanes and Cycloalkanes
Alkanes: general formula CnH2n+2
Cycloalkanes: general formula CnH2n (one ring), CnH2n–2 (two
rings), CnH2n–4 (three rings), etc.
Unbranched alkanes:
(normal alkanes, n-alkanes, "straight chain" alkanes)
CH4
group
suffix
family
suffix
"root"
methane;
CH3–
methyl
C2H6
CH3–CH3
CH3–CH2—
ethane
ethyl
C3H8
CH3CH2CH3
CH3CH2CH2—
propane
propyl
C4H10 CH3CH2CH2CH3
butane
CH3CH2CH2CH2— butyl
More Unbranched Alkanes
(Homologs)
C5H12, CH3(CH2)3CH3, pentane
C6H14, CH3(CH2)4CH3, hexane
C7H16, CH3(CH2)5CH3, heptane
C8H18, CH3(CH2)6CH3, octane
C9H20, CH3(CH2)7CH3, nonane
C10H22, CH3(CH2)8CH3, decane
Homologous Alkanes by Formal Subs3tu3on of Hydrogen Atoms 2˚-H's
1˚-H's
1˚-H's
CH2
CH3
remove
1˚-hydrogen
CH3
propane
add Me
group
CH2
CH3
CH2
CH2
CH3
a propyl group
remove
2˚-hydrogen
CH
CH3
CH3
an isopropyl group
butane
CH3
add Me
group
CH
CH3
CH3
CH2
CH3
isobutane
(2-methylpropane)
Cons3tu3onal Isomers of Pentane 2˚-H's
1˚-H's
CH2
CH3
CH3
CH2
1˚-H's
CH2
CH3
CH3
CH
CH2
CH3
CH2
CH2
2˚-H's
butane
butyl group
sec-butyl
(1-methylpropyl) group
CH3
CH2
CH3
CH3
CH
CH2
CH3
CH2
CH2
CH3
CH3
CH3
CH
3˚-H
CH3
isobutane
(2-methylpropane)
CH2
C
CH3
CH3
2-methylbutane
(isopentane)
CH3
CH3
CH3
CH
CH3
isobutyl
(2-methylpropyl)
group
pentane
CH3
C
CH3
CH3
tert-butyl
(1,1-dimethylethyl)
group
2,2-dimethylpropane
(neopentane)