Download ppt-lec-03-functional-groups-spring-2017

4/29/2017
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Dr Seemal
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1
Organic Chemistry
•
•
•
•
•
•
Introduction
Functional Groups
Alkanes
Alkenes
Alkynes
Alcohols
• Acids, Esters and Amides
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Introduction
• Most organic compounds have a “skeleton” that is
composed of C-C bonds.
– The C-C bonds may be single bonds, double
bonds, or triple bonds.
– Carbon forms a total of 4 bonds.
• The “skeleton” of an organic compound has H’s
attached to it.
– other “heteroatoms” like O, halogens, N, S, and P
may be present as well
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H O
H O
H C C O H
H C C O H
H
H
H
H
H C H
H H
H C C C
H
H H H
H
propane
methane
H O H
H C C H
H C C
acetylene
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H
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C
H
H acetone
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Introduction
• Some familiar organic compounds:
H O
H C C O H
H
H C C O C C
Acetic acid
H
O
H H
H C C O H
H
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H H
H H
“ether”
aspirin
O
C CH3
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H H
C OH
H Ethyl alcohol
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H
H
O
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Introduction
• Organic compounds are commonly classified
and named based on the type of functional
group present.
– An atom or group of atoms that influences the
way the molecule functions, reacts or behaves.
– The center of reactivity in an organic compound
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Functional Groups
• On your exam, you will be responsible for
recognizing and naming the various common
functional groups that are found in organic
compounds:
– Use Table 25.4 and the following slides to help you
study
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Functional Groups
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Class of Compound
Functional Group
Alkane
None
Cycloalkane
None
Alkyl halide
C
X
Alkene
C
C
Alkyne
C
C
Alcohol
C
OH
Ether
C
O
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C
8
Functional Groups
Class of Compound
O
Aldehyde
C
Ketone
C
Carboxylic Acid
Ester
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Functional Group
H
O
C
C
O
C
O
OH
C
O
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C
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Functional Groups
Class of Compound
Amine
Functional Group
C
N
O
Amide
C
N
C
Nitrile
R
R'
R
R'
N
Aromatic ring
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Alkanes
H
H
HH
H
H
H H H
HHC CC C
H C C CC HC
H
H H H
HHH HH
H
• Contain C-C single bonds
– no functional group
• Tetrahedral electron domain geometry CH3CH2CH3
H
CH3CH2CH3
H
CH3CH2CH
H
C C
H
C H
H
H
H carbons H H
•
hybridized
H H H
C C H
H
Free rotation
aroundHsingle
C C bonds
C H
sp3
H
H
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H
H
H H H
H
H
H
C CH
C CH
CH
H C C H
H
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H
H
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H
3
2
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H
CC
C
propane
3
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Cycloalkanes
• Contain C – C with at least 3 of
the carbons arranged in a cyclic
(ring) structure
– No functional group
• Tetrahedral
H
H
H
H
c
c
c c
H
H
H
c
H
H
H
CH2CH2CHCH2CH3
• sp3 hybrid orbitals
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H
•
H
CH =CHCH
AlkylHHalides
H
H
H H
H
C
H
H C C C H
ContainHC-halogen bond
H
H
HC
H
CH2=CHCH3
– F,CHCl,
Br,
or
I
=CHCH
2
3
C
C
H
C H
H H H H
C
C
H H H H
C C C HH C C C C H
H Br H H
H Br H H
H C
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H
H
H CH C HC
C C
H
H
C H
H Br H H
CH3CH(Br)CH2CH3
CH3CH(Br)CH2CH3 CH3CH(Br)CH2CH3
Br
Br
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2
Br
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Alkenes
H
• Contain C=C (carbon-carbon double
bonds)
– 1 sigma bond & 1 pi bond
HH
H
C
CC CC
HH
• Trigonal planar geometry
C
H
H
HH CH
H
C
CH
3
3
H
CH2=CHCH3
CH2=CHCH3
H
H
•
sp2
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hybridized carbons
C
C
H
H
C H
1-propene
H
CH2=CHCH3
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Alkenes
• The C=C present in an alkene is composed of 1
sigma (s) bond and 1 pi (p) bond.
H
H
H
C C
ethylene
H
Double bonds are rigid and cannot rotate freely.
– Rotation would cause loss of overlap of the p orbitals,
destroying the p bond.
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C
H C
C
• Contain C
C
CHH3
Alkynes
H
– 1 sigma bond
– 2 pi bonds
H
H
H
H
C C
C triple
bonds
H
C H
H
H
C
C
H
C H
H
2
H
H
C
C
C
H
CH2=CHCH3
• sp hybridized carbons
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H
H
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H C
C
C
C
H C
• Linear electron domain
geometry
C C
CH =CHCH
H
C
C
C H
HC
CH3
H
H
HC
C
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H
HH
H
C
H
C
H
C H
C
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C
Ph
H
H
Aromatic Ring
H
• Planar ring system with
alternating single and double
bonds
H
C
CC
H
H
H
C
C
H
C
C
C
Ph
H
C
C
H
C
C H
C
C
H
H
hybridized carbons
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H
CH3CHCH3 C
CH3CHCH3
C
C
Ph
C
• Benzene ring is a very common
aromatic ring.
C
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C
CC
H
CH3CHCH3
• Trigonal planar
•
C
H
CCH3CHCH3
C benzene
C
C
HC
H
– does not react like an alkene
sp2
CH
C
C
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C
Ph
C
DrCSeemal
C
H
C
H
C
H Ph
C
C H
C
C
H
N
H
..
N
pyridine
H
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H
C
C
Functional Groups
• Alkanes are often called saturated
hydrocarbons
– Organic compounds composed of carbon and
hydrogen that contain the largest possible number
of hydrogen atoms per carbon atom.
• Alkenes, alkynes, and aromatic hydrocarbons
are called unsaturated hydrocarbons
– Organic compounds composed of carbon and
hydrogen that contain less hydrogen than an
alkane having the same number of carbon atoms
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Alcohols CH CH(OH)CH CH(CH )
3
2
3 2
CH3CH(OH)CH2CH(CH
H
• Contain C-O-H bond
– hydroxyl group
H
• Alcohols form hydrogen
bonds.
H
H
O
C
C
H
H
C
H
H
H
H
C
C
C
H
OH H
CH CC
• Amphoteric (acids as well
as base)
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H
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H
H
C
H
C
HH
H
H CH(CH
C H)
OH
CH CH(OH)CH
H
H
3
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H
H
2
H
3 2
H
OH
H
O
H
H
H
C
C
C
C
C 19 H
CH3CH(OH)CH2CH(CH3)2
H
Ethers
O
O
H
H
C
C
• tetrahedral e.d.
geometry
H ) HH
H H H CH(CH
CH CH(OH)CH
H
• Contain
bond
H C C C-O-C
H
H
H
H
O
H
HH
H
C
H
HH
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C
H
H
O
H
HH
C
H
C
H
H
H
HH
H
H
H
C
C
O
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(CH
H2)2O
H3CH
H
CH2OCH2CH3
3
H CH
CH
CH2OCH2CH3
3
OH
(CH3CH2)2O
(CH3CH2)2O
C C H
H C C OOHC C H
H HH
H H
molecularHgeometry
H
H
H
• bent
H
H
3
2
3 2
CH
CH(OH)CH
CH(CH
)
3
2
3 2
H C C O C C
CH3CHO
H
C
C
H H
CH3CH2OCH2CH
O C C H
O
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Amines
H H
H C
• Contain C-N-R
H
H
HH H HH H H
H H H H H
H
H
H
H
HC C
C C C H CHC N
C HH
C C
H
H CC C C C C C CC CN NC C
H
H
H H
R’
– R and R’ can be H or C
H
H H
HH HH H
HH H H H H H HH HH HH H
H
CH
CH2CH2CH2CH
CH3CH2CH2CH2CH
NHCH
2 3
3
CH
CH
CH2NHCH
CH
CH
CHCH
CHCH
CH
2 2NHCH
3
3 3 2 2 2 2 2
3
• Primary and secondary
amines form hydrogen
bonds.
• Common organic bases
– lone pair of e- on N
CH3NH2
o
1
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H
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primary
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H
HH
N
NN
CH3NHCH3
o
2
secondary
H
N
(CH3)3N
o
3
tertiary
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H HO O
Aldehydes
• Contain
O
(-CHO)
C - H
H
H HC C C C H
H O
H H
C C H
H
• Carbonyl (C=O)
– always on the 1st or last carbon in a
chain
• Trigonal planarHgeometry
O
• sp2 hybrid orbitals
H C C H
H
CHCH
CHO
CHO
3
3
CH3CHO O O
H H
O
O
H
H
C
C
H
H
H
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CH CHO
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H
Ketones
O
– Carbonyl attached to middle of chain
CH3C(O)CH3
H
O
H
C
C
C
• Trigonal planar e.d. geo.
H
H
H
• sp2 hybridized C
CH3CHO
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O
C
C
H
H
• Contain C-C-C
H
H
Chem-160
CH3CHO
CH3C(O)CH3
C H
H
H
C
H O H
C
C
H
C
H
O
C
H
H
O
HH
H 3C(O)CH3
CH
CH
H 3CHO C
C
O O H
HH
H
H
O
H
H
H H C C CHH H
C H C
C
H
C
C
H
H
H
H
H
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H
CH3CHO
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N
N
Carboxylic Acids
H
CH3NH
NHCH3 (CH
)3NH 3)3N
CH2 3NHCH
3 CH3NHCH
3 (CH
2
3
O
o group
• Contain carboxyl
1
2
1
o
o
-CO2-CO
H 2H
H
o
o
H
O
H
3
2
3 H
o
C
C
C
O
H H
O H
O
H
H
hybridized carbon
HO
C
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HH
C
OH
OH
OH
H
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C
C
CH CHCH
COCH
H CO H
2
2
CH3CH23CO2H
3
2
2
O
• trigonal planar
•
C
C
H O
C HC C
O CH C O H
CH3CH2CO2H
H
H
-COOH
-COOH
H H
H H
H
• Form hydrogen bonds
sp2
H
H
O
C
OH
O
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H
H
C
H
•
C
C
OH
Esters
O
OOH
HH
HH HH
H
O
H
H
H H
H H O
CO
HH
C C CC CCC OOH CC
C
C
C
H
Contain
H C C C O C C H
HH HH
HH
H
H
H
H group
-CO2R where R = alkyl
HH HH
H
H
CC H
H
H
H
CHCH
CHCO
COCH
CHCH
CH3
CH3CH2COCH
CH
3CH
2
2
2
3
2
2
2
3
2
2
3
CH3CH2CO2CH
CH
2
3
• trigonal planar
• sp2 hybridized
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O
O
H
H
H
H
H
H
H
O
HH
H
H
O
H
H
C H
H
O
H
C
H
H
C
O
C
C HOO C CC C H C
H
H
C
C
H
H
C
C
H
C
C
C C
CH
C
H HH H
O
H HH
HHHO
H OO H
H
H
Chem-160
-CO2R where R = alkyl group
25
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-CORR=where
R = alkyl group
-CO R where
alkyl group
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O
Amides
H O
H
• Contain
– where R and R’ = H
H orCC C
C
H
H
H
H
H O
H HC CH CC CC
H
N C HHC HHH
H
H
• C=O is trigonal planar &
sp2 hybridized
H
HH
C
C
H
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Chem-160
C
O
O
N
N
H
H
C
C
C
C HH
H HH HH
H
HH
H
H
NH
H
H H
C H
O
C
H
H
H H C C C OOC C H H
C
C
CH
O
HH
H
C
C
HH
H
H
H
O
HH
-CO2R where R = alkyl group
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H H
H
CHCH
CH2CONHCH
CONHCH2CH
CH
CH
33
2
2 3 3
CH3CH2CONHCH2CH3
H
H O
-CO2R where R = alkyl26group
H O H
H H
C H
O
C
H
C
C
C
C C N C C H
H
H
O
H
H
H • Contain
H H H
Nitriles
H
O
O
O
CH2•CONHCH
Linear 2CH3
H
3
CH3CNH2
CH3CNHCH3 CH3CN(CH3)2
N
o
o
o
1
2
3
•
sp
hybridized
C
H
O
HH
H
C H
O
C
C H CC C N
N
CH3CN
H
O
HHH
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O
O Jelani
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H
H
CH3
27
H
Functional Groups
Example: Identify the functional groups present in the following
compounds.
I
I
HO
O
I
NH2
CH2CHCOOH
I
thyroxine
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NH
Functional Groups
Example:
HO2C
Identify the functional groups in the following
compounds.
NH2
O
C
O
OH
OH
Lisinopril
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O
H
OCH3
Vanillin
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C
O
N
N
H
H
O
C
HO2C
N
N
29
Depicting Structures of Organic
Compounds
• Organic compounds can be depicted using a
variety of formulas:
–
–
–
–
–
–
–
Empirical formula
Molecular formula
Lewis structure
Full structural formula
Three dimensional drawings
Condensed structural formula
Line angle drawings
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30
Depicting Structures of Organic
Compounds
• Ethyl acetate is an organic molecule with:
– empirical formula = C2H4O
– molecular formula = C4H8O2
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Depicting Structures of Organic
Compounds
• Ethyl acetate is an organic
molecule with:
. ..
.
H O
– Lewis structure:
• depicts all covalent bonds using a
straight line and shows all
nonbonding pairs of electrons
H
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C
H
. .
– Full structural formula:
• a Lewis structure without the
nonbonding electrons
C
..
O
..
H
H
C
C
H
H
H
..
..
H
O
C
C
H
H
O
H
H
C
C
H
H
H
32
Depicting Structures of Organic
Compounds
.
..
• Ethyl acetate is. an
organic
..
molecule with:
– 3-d drawing:
. .
H
H O
H
O
H
O
H
HH
C..
C HO C C CH H
.. H
C
H
C
C H OH
H
H H H
H
C C H
H C C O
– Condensed
structural
formula
H
H H
CH3CO2CH2CH3
– Line angle drawing
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CH3CO2CH2CH3
O
..
O
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33
Alkanes
Some of the simplest alkanes:
Condensed
Formula
Name
CH4
methane
CH3CH3
ethane
CH3CH2CH3
propane
CH3CH2CH2CH3
butane
CH3CH2CH2CH2CH3
pentane
4/29/2017
You must
know these!!!
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34
Alkanes
Some of the simplest alkanes:
Condensed
Formula
Name
CH3CH2CH2CH2CH2CH3
hexane
CH3CH2CH2CH2CH2CH2CH3
heptane
CH3CH2CH2CH2CH2CH2CH2CH3
octane
CH3CH2CH2CH2CH2CH2CH2CH2CH3
nonane
CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3
decane
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35
Alkanes
• The previous alkanes are also called straightchain hydrocarbons:
– all of the carbon atoms are joined in a continuous
chain
• Alkanes containing 4 or more carbons can also
form branched-chain hydrocarbons (branched
hydrocarbons)
– some of the carbon atoms form a “branch” or sidechain off of the main chain
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36
Alkanes
• An example of a straight chain hydrocarbon:
– C5H12 CH3CH2CH2CH2CH3 pentane
• Examples of a branched hydrocarbon:
– C5H12
CH3CHCH2CH3
CH3
CH3
CH3 C CH3
2-methylbutane
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Chem-160
CH3
2,2-dimethylpropane
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37
Alkanes
• The three structures shown previously for C5H12
are structural isomers:
– compounds with the same molecular formula but
different bonding arrangements
• Structural isomers generally have different
properties:
– different melting points
– different boiling points
– often different chemical reactivity
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38
Alkanes
• Organic compounds can be named either
using common names or IUPAC names.
• You must be able to name alkanes, alkenes,
alkynes, and alcohols with 10 or fewer
carbons in the main chain using the IUPAC
naming system.
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Alkanes
• Alkane Nomenclature:
– Find the longest continuous chain of carbon
atoms and use the name of the chain for the base
name of the compound:
• longest chain may not always be written in a straight
line
1
CH3 -2 CH - CH3
3 CH2
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- CH2 - CH2 - CH3
4
5
Base name:
hexane
6
Chem-160
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40
Alkanes
• Alkane Nomenclature:
– Number the carbon atoms in the longest chain
beginning with the end of the chain closest to a
substituent
• groups attached to the main chain that have taken the
place of a hydrogen atom on the main chain
1
A substituent
CH3 -2 CH - CH3
3 CH2
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- CH2 - CH2 - CH3
4
5
6
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41
Alkanes
• Alkane Nomenclature:
– Name and give the location of each substituent
group
• A substituent group that is formed by removing an H
atom from an alkane is called an alkyl group:
– Name alkyl groups by dropping the “ane” ending
of the parent alkane and adding “yl”
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42
Alkanes
• Alkane Nomenclature:
– Common alkyl groups (substituents):
1
CH3
CH3CH2
CH3CH2CH2
CH3CH2CH2CH2
methyl
ethyl
propyl
butyl
CH3 -2 CH - CH3
3 CH2
4/29/2017
Know
these!
- CH2 - CH2 - CH3
4
5
6
Chem-160
2-methylhexane43
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Alkanes
• Alkane Nomenclature:
– Halogen atoms are another common class of
substituents.
• Name halogen substituents as “halo”:
–
–
–
–
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Cl chloro
Brbromo
I
iodo
F
fluoro
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44
Alkanes
• Alkane Nomenclature:
– When two or more substituents are present, list them
in alphabetical order:
• Butyl vs. ethyl vs. methyl vs. propyl
– When more than one of the same substituent is
present (i.e. two methyl groups), use prefixes to
indicate the number:
•
•
•
•
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Di = two
Tri = three
Tetra = four
Penta = five
Know these.
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45
Alkanes
Example: Name the following compounds:
CH3CH2CHCH2CH3
CH3
CH2CH2CH3
CH3CHCHCH3
CH3
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46
Alkanes
Example: Name the following compounds:
CH3CH2CHCH3
CH2CH2Br
CH2CH2CH3
CH3CHCHCH3
Cl
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Alkanes
• You must also be able to write the structure of an
alkane when given the IUPAC name.
• To do so:
– Identify the main chain and draw the carbons in it
– Identify the substituents (type and #) and attach them
to the appropriate carbon atoms on the main chain.
– Add hydrogen atoms to the carbons to make a total of
4 bonds to each carbon
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Alkanes
Example: Write the condensed structure for the
following compounds:
3, 3-dimethylpentane
3-ethyl-2-methylhexane
2-methyl-4-propyloctane
1, 2-dichloro-3-methylheptane
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Alkenes
• Alkenes:
– unsaturated hydrocarbons that contain a C=C
double bond
• Alkene Nomenclature:
– Names of alkenes are based on the longest
continuous chain of carbon atoms that contains
the double bond.
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Alkenes
• Alkene Nomenclature
– Find the longest continuous carbon chain
containing the double bond.
– Change the “ane” ending from the corresponding
alkane to “ene”
• butane
• propane
• octane
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butene
propene
octene
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Alkenes
• Alkene Nomenclature
– Indicate the location of the double bond using a prefix
number
• designate the carbon atom that is part of the double bond
AND nearest to the end of the chain
– Name all other substituents in a manner similar to the
alkanes.
– Use a prefix to indicate the geometric isomer present,
if necessary.
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Alkenes
• Alkene Nomenclature
• Different geometric isomers are possible for
many alkenes.
– Compounds that have the same molecular formula
and the same groups bonded to each other, but
different spatial arrangements of the groups
• cis isomer
• trans isomer
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Alkenes
• Alkene Nomenclature
– Cis isomer:
• two identical groups (on adjacent carbons) on the same
side of the C = C double bond
– Trans isomer:
• two identical groups (on adjacent carbons) on opposite
sides of the C = C double bond
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Alkene
CH3
CH3
CH3
C=C
H
C=C
H
H
CH3
trans-2-butene
cis-2-butene
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H
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Alkene
For an alkene with the general formula
A
P
C=C
B
Q
cis and trans isomers are possible only if
A = B and
P=Q
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Alkene
Example: Name the following alkenes:
CH3CH2
H
C=C
H
CH3CH2
CH3CHCH2
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H
H
C=C
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CH2CH3
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Alkenes
Example: Draw the structures for the following
compounds:
2-chloro-3-methyl-2-butene
trans-3, 4-dimethyl-2-pentene
cis-6-methyl-3-heptene
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Alkynes
• Alkynes:
– unsaturated hydrocarbons that contain a
C C triple bond
• Alkyne Nomenclature:
– Identify the longest continuous chain containing
the triple bond
– To find the base name, change the ending of the
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Alkynes
• Alkyne Nomenclature:
– Use a number to designate the position of the
triple bond
• number from the end of the chain closest to the triple
bond
– just like with alkenes
– Name substituents like you do with alkanes and
alkenes
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Alkynes
Example: Name the following compounds:
CH3CH2C CCHCH3
CH2CH3
ClCH2CH2C CH
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Alkynes
Example: Draw the following alkynes.
4-chloro-2-pentyne
3-propyl-1-hexyne
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