Transcript Slide 1

ALKYNES
ALKYNES
-Characterized by C
C triple bond(s)
-Classified as unsaturated hydrocarbons
-empirical formula = CnH2n-2
(applies when the molecule only has one triple bond)
 CnH2n-2, n=5
= C5H8
ALKYNES
Properties:
-Are hydrophobic like all hydrocarbons
-Have higher boiling points than alkanes and alkenes due to
their ability to stack
ALKYNES
Some IUPAC names of alkynes:
ethyne
propyne
but-1-yne
All alkynes have the suffix “yne”
ALKyNES
IUPAC naming system:
prefix
Number of
carbons in the
longest chain
-#-
suffix
family
Location
number
Ex: but-1-yne
ALKYNES
IUPAC naming system:
Name the following alkynes:
hex-1-yne
hex-3-yne
ALKYNES
IUPAC naming system:
Name the following alkynes:
5
6
7
1
2
3
4
4-methylhex-2-yne
9
8
2
6
5
4
1
3
5-ethyl-4,6,7-trimethylnon-2-yne
The triple bond has a higher numbering priority
than the alkyl and halide substituents
ALKYNES
IUPAC naming system:
Name the following alkynes:
1
5
6
3
4
2
3
2
4
5
7
1
hex-4-en-1-yne
6
3-ethylhept-1-en-4-yne
Alkenes are ordered first in the name, and the “e” ending
is dropped.
Generally, double bonds and triple bonds have equal
numbering priority* (aim to get the lowest numbers).
ALKYNES
IUPAC naming system:
Name the following alkynes:
5
6
1
2
3
4
4
3
2
5
1
6
hex-1-en-5-yne
or
hex-5-en-1-yne
*Double bonds have higher priority than triple bonds
whenever there is ambiguity in their numbers. This
uses the rule where alpha-order is final tie-breaker
like before.
ALKYNES
IUPAC naming system:
Name the following alkynes:
4
3
6
2
7
1
cyclononyne
5
8
cyclooct-1-en-4-yne
ALKYNES
IUPAC naming system:
Name the following alkyne:
Cl
2
1
3
9
Cl
4
8
5
7
F
6
Cl
F
F
3,4,5-trichloro-8,9-diethyl-5,7,7-trifluorocyclononyne
ALKYNES
Drawing alkynes:
Draw the following alkynes using line diagrams
non-2-yne
non-1-yne
1
8
9
4
6
7
8
3
5
9
4
6
7
5
2
1
The triple bond cannot bend, so the bonds
adjacent to a triple bond must be straight.
2
3
ALKYNES
Drawing alkynes:
Draw the following alkynes using structural diagrams
4,5-dibromohex-2-yne
1,2-dimethylcyclooct-1-en-4-yne
H
H
H C
H
C C
H H
H
C C
C H
Br Br H
H C H H
H
H C
C
C
H
H
H C
C
H
C
C
H
H
H
C
C
H
ALKENES
RECALL:
Name the following alkenes:
4-methylpenta-1,3-diene
hepta-1,3,6-triene
When there is more than one double bond, add
the letter “a” to the end of the prefix (i.e. buta)
ALKYNES
Multiple Double Bonds AND/OR Triple Bonds:
octa-2,4-dien-6-yne
When there is more than one double bond AND a
triple bond, add the letter “a” to the end of the
prefix (i.e. buta)
dec-1-ene-4,9-diyne
When there is more than one triple bond, AND a
double bond, add the letter “e” to the end of the
double bond sufix -ene
ALKYNES
undeca-1,6,-diene-3,9-diyne
nona-5-7-diene-1,3-diyne