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Chapter
23
Organic Chemistry
Chemistry 4th Edition
McMurry/Fay
Dr. Paul Charlesworth
Michigan Technological University
Alkanes
•
01
Alkanes: Have the general formula CnH2n + 2,
where n = 1, 2, . . . . Each carbon has a tetrahedral
arrangement.
•
These are saturated hydrocarbons: They contain
the maximum number of atoms that can bond to a
carbon atom.
Prentice Hall ©2004
Chapter 23
Slide 3
Alkanes
Prentice Hall ©2004
02
Chapter 23
Slide 4
Alkanes
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
Prentice Hall ©2004
CH4
CH3CH3
CH3CH2CH3
CH3(CH2)2CH3
CH3(CH2)3CH3
CH3(CH2)4CH3
CH3(CH2)5CH3
CH3(CH2)6CH3
CH3(CH2)7CH3
CH3(CH2)8CH3
03
Undecane
Dodecane
Tridecane
Icosane
Henicosane
Docosane
Tricosane
Triacontane
Tetracontane
Hectane
Chapter 23
CH3(CH2)9CH3
CH3(CH2)10CH3
CH3(CH2)11CH3
CH3(CH2)18CH3
CH3(CH2)19CH3
CH3(CH2)20CH3
CH3(CH2)21CH3
CH3(CH2)28CH3
CH3(CH2)38CH3
CH3(CH2)98CH3
Slide 5
Alkanes
04
•
Nomenclature is based on the International Union
of Pure and Applied Chemistry (IUPAC) system.
•
Parent name is the longest continuous chain.
•
Side chain numbering gives the lowest total count.
•
A prefix such as: di-, tri-, or tetra- indicates the
number of identical chains.
Prentice Hall ©2004
Chapter 23
Slide 6
Alkanes
•
There are often many
different substituents.
•
If we cannot resolve
them numerically, we
may do so
alphabetically.
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05
–NH2
–F
–Cl
–Br
–I
–NO2
–CN
–CH=CH2
Chapter 23
amino
fluoro
chloro
bromo
iodo
nitro
cyano
vinyl
Slide 7
Alkanes
•
•
•
Alkyl substituents
derive their names
from their parent
alkanes.
06
Methyl
–CH3
Ethyl
–CH2CH3
n-Propyl
–CH2CH2CH3
n-Butyl
–CH2CH2CH2CH2CH3
The n- means
Isopropyl
attachment on end.
CH3
C H
CH3
The iso- means on t-Butyl (tertiary butyl)
a central atom.
Prentice Hall ©2004
Chapter 23
CH3
C CH3
CH3
Slide 8
Cycloalkanes
•
01
Cycloalkanes are joined in rings and have the
general formula CnH2n.
Prentice Hall ©2004
Chapter 23
Slide 9
Cycloalkanes
•
02
Cyclic structures are simplified by using polygons
and lines. At every line junction it is understood
that a carbon and the correct number
of hydrogen atoms exist.
Prentice Hall ©2004
Chapter 23
Slide 10
Cycloalkanes
•
03
Start numbering substituted cycloalkanes with the
group that has “alphabetical priority.”
H2
C
5
H2C 4
3
CH
H2
C
1CH
CH3
2
CH2
H3C
1-ethyl-3-methylcylcopentane
Prentice Hall ©2004
Chapter 23
Slide 11
Alkenes
01
•
Alkenes: Contain at least one carbon–carbon
double bond. Alkenes have the general formula
CnH2n.
•
Alkenes: Unsaturated hydrocarbons, which means
that they do not have the maximum number of
hydrogen atoms. These are taken up by double
bonds.
Prentice Hall ©2004
Chapter 23
Slide 12
Alkenes
02
•
The names of compounds containing C=C bonds
end in -ene.
•
In naming alkenes we indicate the positions where
the carbon–carbon double bonds begin.
H2C
C
H
C
H2
CH3
H3C
1-butene
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C
H
C
H
CH3
2-butene
Chapter 23
Slide 13
Alkenes
03
•
Double bonds are rigid and do not allow rotation.
This creates geometric isomers.
•
Geometric isomers have the same chemical
formula, but a different structural arrangement.
•
The two main isomers are:
cis - meaning “on the same side.”
trans - meaning “on opposing side.”
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Chapter 23
Slide 14
Alkenes
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04
Chapter 23
Slide 15
Alkenes
•
05
Cis–trans isomerism occurs because the
electronic structure of the carbon–carbon double
bond makes rotation energetically unfavorable.
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Chapter 23
Slide 16
Alkynes
•
Alkynes: Contain at least one carbon–carbon triple
bond. They have the general formula CnH2n – 2.
•
Names of compounds with the carbon–carbon triple
bond end with -yne.
Prentice Hall ©2004
Chapter 23
Slide 17
Aromatic Hydrocarbons
•
01
The base unit for all aromatic hydrocarbons is the
benzene ring. Its structure was proposed by Kekulé
in 1865 (often represented as Ar–H).
Prentice Hall ©2004
Chapter 23
Slide 18
Aromatic Hydrocarbons
02
•
Benzene’s relative lack of reactivity is a result of its
electronic structure which contains six sp2hybridized orbitals.
•
Benzene has two resonance forms shown in (c).
Prentice Hall ©2004
Chapter 23
Slide 19
Aromatic Hydrocarbons
•
03
The naming of substituted benzenes, in which one
hydrogen is replaced, is as follows:
CH3
CH2
ethylbenzene
Prentice Hall ©2004
Cl
Br
chlorobenzene
bromobenzene
Chapter 23
F
fluorobenzene
NO2
nitrobenzene
Slide 20
Aromatic Hydrocarbons
•
04
Some benzene compounds have common names:
CH3
Toluene
OH
Phenyl
Phenol
CH3
O
CH3
NH2
CH2
Anisol
Benzyl
OH
O
C
O
C
Acetophenone
Anisole
Benzoic Acid
Prentice Hall ©2004
Chapter 23
OH
O
O
S
Benzenesulfonic
acid
Slide 21
Aromatic Hydrocarbons
•
05
If more than one substituent exists, each has a
numbered position. Generally, the 1-position is
assigned arbitrarily.
•
The 1-position is, however, taken by functional
groups that are responsible for common names,
such as -CH3, -NH2, -NO2, and OH.
Prentice Hall ©2004
Chapter 23
Slide 22
Aromatic Hydrocarbons
•
06
If more than one substituent exists, each has a
numbered position.
•
Generally, the 1-position is assigned arbitrarily.
•
The 1-position is, however, taken by functional
groups that are responsible for common names,
such as -CH3, -NH2, -OH, -COOH, and -COH.
Prentice Hall ©2004
Chapter 23
Slide 23
Aromatic Hydrocarbons
•
07
D
A common designation
1
of the position of the
Ortho
second substituent is
the use of the prefixes,
6
2
5
3
Meta
Meta
4
ortho, meta, and para.
Prentice Hall ©2004
Ortho
Para
Chapter 23
Slide 24
Aromatic Hydrocarbons
Br
08
NO2
NO2
Br
1,3-dibromobenzene
meta-dibromobenzene
Prentice Hall ©2004
1,2-dinitrobenzene
ortho-dinitrobenzene
Chapter 23
Slide 25
Aromatic Hydrocarbons
Br
1
CH3
1
6
2
Br
4
1,3-dibromobenzene
2
3-bromotoluene
2
3-bromophenol
O
3
4
C
1
6
2
Br
3-bromobenzoic Acid
Chapter 23
Br
4
C
1
5
3
5
OH
3
3-bromoaniline
Br
4
6
Br
6
3
O
4
Prentice Hall ©2004
2
5
NH2
1
5
OH
1
6
3
5
6
09
H
2
3
5
4
Br
3-bromobenzaldehyde
Slide 26
Functional Groups: Alcohols
01
•
Alcohols: Contain the hydroxyl functional group, –
OH which replaces an –H in the alkane.
•
Alcohols are named by replacing the “-e” ending of
the alkane with a “-ol” ending. The carbon of
attachment is indicated with the smallest number.
•
methane, CH4, gives methanol, CH3OH
•
ethane, C2H6, gives ethanol, C2H5OH
•
Propane,
Prentice Hall ©2004
CH3 CH2 CH3 ,
gives 2-propanol,
Chapter 23
OH
CH3 CH
CH3
Slide 27
Functional Groups: Alcohols
•
02
Primary Alcohols have their –OH bonded to a
terminal carbon that is bonded to one carbon and
two hydrogens. A common preparation is given
below.
Prentice Hall ©2004
Chapter 23
Slide 28
Functional Groups: Alcohols
•
03
Secondary alcohols have their –OH bonded to a
carbon that is bonded to two other carbons and one
hydrogen. A common preparation is given below.
Prentice Hall ©2004
Chapter 23
Slide 29
Functional Groups: Ethers
01
•
Ethers: Contain the R–O–R’ linkage, where R and
R’ are a hydrocarbon group.
•
Their names derive directly from the two alkyl
groups, R and R’, attached to the oxygen.
•
•
CH3OCH3 dimethyl ether
•
CH3CH2OCH3 ethylmethyl ether or methylethyl ether
Ethers are inert chemically and make good
solvents.
Prentice Hall ©2004
Chapter 23
Slide 30
Functional Groups: Ethers
•
02
Ethers can be produced from two alcohols:
H2SO4
CH3OH + HOCH3  CH3OCH3 + H2O
Catalyst
Prentice Hall ©2004
Chapter 23
Slide 31
Functional Groups: Amines
•
01
Amines: Are organic bases with the general
formula R3N where R may be H or a hydrocarbon
group. Their names are derived from the alkyl
groups attached to the nitrogen.
H3 C
N
H
H3 C
N
CH3
H
H
Methylamine
(Primary)
N,N-dimethylamine
(Secondary)
Prentice Hall ©2004
Chapter 23
H3 C
N
CH3
CH3
N,N,N-trimethylamine
(Tertiary)
Slide 32
Functional Groups: Amines
•
02
Amines are bases like ammonia.
CH3NH2 + H2O  CH3NH3+ + OH–
•
They are easily protonated (neutralized) in acid
solution to form soluble amine salts.
(CH3CH2)2NH + HCl  (CH3CH2)2NH2Cl(aq)
Prentice Hall ©2004
Chapter 23
Slide 33
Functional Groups: Carbonyl
•
01
Carbonyl (Pronounced Car–bo–neel): Has a
carbon–oxygen double bond (C=O).
Prentice Hall ©2004
Chapter 23
Slide 34
Functional Groups: Carbonyl
•
02
Aldehydes: Have the terminal carbonyl functional
O
group, -CHO,
R C
H
•
They are named by replacing the -e ending of the
alkane by an -al ending. Numbering begins with the
aldehyde carbon.
CH3
O
CH3 C
CH3 CH
H
ethanal
Prentice Hall ©2004
O
C
H2
C
H
3-methylbutanal
Chapter 23
Slide 35
Functional Groups: Carbonyl
•
03
Aldehydes are prepared by oxidizing primary
alcohols. An example is given below where
methanal (formaldehyde) is prepared from
methanol.
Prentice Hall ©2004
Chapter 23
Slide 36
Functional Groups: Carbonyl
•
04
Ketones: Have the carbonyl functional group
bonded between two hydrocarbon units.
C
•
O
C
C
Ketones are named by replacing the -e ending of
the alkane with the -one ending and prefixing the
name with the number of the carbonyl carbon.
Prentice Hall ©2004
Chapter 23
Slide 37
Functional Groups: Carbonyl
•
05
Ketones are prepared by the oxidation of
secondary alcohols as the example below shows
for the preparation of propanone (acetone).
Prentice Hall ©2004
Chapter 23
Slide 38
Functional Groups: Carbonyl
•
Carboxylic Acids: Contain the carboxyl functional
group, –COOH or –CO2H.
O
C
•
06
OH
They are named by replacing the -e ending of the
alkane with the -oic ending.
O
H3C
C
OH
Ethanoic Acid
(Acetic Acid)
Prentice Hall ©2004
O
CH3 O
H3C
H2
C
C
H
C
OH
2-methylbutanoic acid
Chapter 23
C
OH
Benzoic Acid
Slide 39
Functional Groups: Carbonyl
•
Carboxylic acids are prepared by the oxidation of
aldehydes or primary alcohols.
O
H3C CH2 OH
•
07
O2
H3C
C
O
H
O2
H3C
C
OH
Carboxylic acids dissociate as weak acids to give
the carboxylate anion and the hydronium ion.
CH3CO2H + H2O  CH3CO2– + H3O+
Prentice Hall ©2004
Chapter 23
Slide 40
Functional Groups: Carbonyl
•
08
Esters: have the general formula R’COOR or
R’CO2R, where R’ can be H or a hydrocarbon
group and R is a hydrocarbon group.
O
R
•
C
O
R'
They are the product of a reaction between a
carboxylic acid and an alcohol, eliminating water
and forming the “organic salt,” the ester.
O
O
H
H
R
C
Prentice Hall ©2004
O
H + H
O
R'
Chapter 23
R
C
O
R'
+
O
Slide 41
Functional Groups: Carbonyl
•
08
Ester names are derived from the acid name where
the -oic ending is replaced by the -oate ending and
prefixing this with the name of the attached alkyl
group (which comes from the alcohol).
O
H3C
O
C
H3C
O
CH3
Methyl Ethanoate
(methyl acetate )
Prentice Hall ©2004
O
C
H C
O
CH2CH3
Ethyl Ethanoate
(ethyl acetate )
Chapter 23
O
CH2CH3
Ethyl Methanoate
(ethyl formate)
Slide 42
Functional Groups: Carbonyl
•
09
Esters are commonly found or used in:
•
Medicines (aspirin)
•
Anesthetics (benzocaine)
•
Polymers (Polyesters, Dacron, Mylar)
•
Fragrant odors of food and flowers
Prentice Hall ©2004
Chapter 23
Slide 43
Functional Groups: Carbonyl
10
•
Amides: Often known in the peptide bond, it
consists of a carbonyl and an amine group on the
same carbon.
•
Formed when an acid and a basic amine react.
O
O
C
C
OH H
N
N
+
H2O
H
H
Acid
Prentice Hall ©2004
Amine
Amide
Chapter 23
Slide 44
Functional Groups: Carbonyl
•
11
Amides are named by replacing the -oic ending of
the acid by the -amide ending and then prefixing
this name with the N-alkyl groups on the amine.
O
N-ethylbutanamide
N
H
O
N
H
Prentice Hall ©2004
N-methylethanamide
(N-methylacetamide)
Chapter 23
Slide 45
Functional Groups: Carbonyl
•
The amide bond is the fundamental link used by
organisms to form proteins.
•
Some synthetic polymers and pharmaceutical
agents are amides.
Prentice Hall ©2004
Chapter 23
12
Slide 46