chapter 11 unsaturated hydrocarbons
Post on 31-Dec-2015
105 Views
Preview:
DESCRIPTION
TRANSCRIPT
2
Saturated hydrocarbons• have the maximum number of hydrogen atoms
attached to each carbon atom.• are alkanes and cycloalkanes with single C-C
bonds.
CH3—CH2—CH3
Saturated Hydrocarbons
3
Unsaturated hydrocarbons• have fewer hydrogen
atoms attached to the carbon chain than alkanes.
• are alkenes with double bonds.
• are alkynes with triple bonds.
Unsaturated Hydrocarbons
4
Bond Angles in Alkenes and Alkynes
According to VSEPR theory: • the three groups bonded to
carbon atoms in a double bond are at 120° angles.
• alkenes are flat because the atoms in a double bond all lie in the same plane.
• the two groups bonded to each carbon in a triple bond are at 180° angles.
5
Naming Alkenes
The names of alkenes • use the corresponding alkane name.• change the ending to –ene.
Alkene IUPAC Common
H2C=CH2 ethene ethylene
H2C=CH─CH3 propene propylene
cyclohexene
6
Ethene (Ethylene)
Ethene or ethylene• is an alkene with the formula
C2H4.• has two carbon atoms connected
by a double bond. • has two H atoms bonded to each
C atom.• is flat with all the C and H atoms
in the same plane.• is used to accelerate the ripening
of fruits.
7
Naming Alkynes
The names of alkynes • use the corresponding alkane name.• change the ending to –yne.
Alkyne IUPAC Common
HC≡CH ethyne acetylene
HC≡C─CH3 propyne
8
Naming Alkenes and Alkynes
When the carbon chain of an alkene or alkyne has four or more C atoms, number the chain to give the lowest number to the first carbon in the double or triple bond.
CH2=CH─CH2─CH3 1-butene
1 2 3 4
CH3─CH=CH─CH3 2-butene
1 2 3 4
CH3─CH2─CC─CH3 2-pentyne
5 4 3 2 1
9
Learning Check
Write the IUPAC name for each of the following:
1. CH2=CH─CH2─CH3
2. CH3─CH=CH─CH3
CH3
|3. CH3─CH=C─CH3
4. CH3─CC─CH3
10
Solution
Write the IUPAC name for each of the following:
1. CH2=CH─CH2─CH3 1-butene
2. CH3─CH=CH─CH3 2-butene
CH3
|3. CH3─CH=C─CH3 2-methyl-2-butene
4. CH3─CC─CH3 2-butyne
11
Learning Check
Write the IUPAC name for each of the following:
A. CH3─CH2─C≡C─CH3
CH3
B. CH3─CH2─C=CH─CH3
top related