Chemistry 121 Winter 2016
Introduction to Organic Chemistry and Biochemistry
Instructor Dr. Upali Siriwardane (Ph.D. Ohio State)
E-mail: upali@latech.edu
Office: 311 Carson Taylor Hall ; Phone: 318-257-4941;
Office Hours: MTW 8:00 - 10:00 am;
ThF 9:00 - 10:00 am 1:00 - 2:00 pm.
December 18, 2015: Test 1 (Chapters 12-13)
January 25 , 2016: Test 2 (Chapters 14-16)
February 17, 2016: Test 3 (Chapters 17-19)
February 29, 2016: Test 4 (Chapters 20-22)
March 1 , 2016:
Make Up Exam: Chapters 12-22)
Bring Scantron Sheet 882-E
Chemistry 121, Winter 2016, LA Tech
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1-1
Chapter 15: Aldehyde and Ketones
15-1 The Carbonyl Group
15-2 Compounds Containing a Carbonyl Group
15-3 The Aldehyde and Ketone Functional Groups
15-4 Nomenclature for Aldehydes
15-5 Nomenclature for Ketones
15-6 Isomerism for Aldehydes and Ketones
15-7 Selected Common Aldehydes and Ketones
15-8 Physical Properties of Aldehydes and Ketones
15-9 Preparation of Aldehydes and Ketones
15-10Oxidation and Reduction of Aldehydes and Ketones
15-11Reaction of Aldehydes and Ketones with Alcohols
15-12Sulfur-Containing Carbonyl Groups
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Carbonyl Group
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Simplest Aldehyde
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Common Names of Aldehyde and
Ketones
Aldehydes:
Fomaldehyde:
HCHO
Acetaldehyde:
CH3CHO
Propionaldehyde:
CH3CH2CHO
Butyraldehyde:
CH3CH2CH2CHO
Valeraldehyde:
CH3CH2CH2CH2CHO
Ketones:
Acetone:
CH3COCH3
Methyl ethyl ketone
CH3CH2COCH3
Butyl propyl ketone
CH3CH2CH2CH2COCH2CH2CH3
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IUPAC Nomenclature of Aldehyde and
Ketones
The IUPAC system deals with functional groups
two different ways.
Modification of the hydrocarbon name to
indicate the presence of a functional group.
aldehyde, -CHO
use -al ending.
Ketones -RCOR’
use -one ending.
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IUPAC Nomenclature of Aldehyde and
Ketones
The IUPAC system deals with functional
groups two different ways.
Modification of the hydrocarbon name to
indicate the presence of a functional group.
aldehyde, -CHO
use -al ending.
Ketones -RCOR’
use -one ending.
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Example
C - C - C - C - CHO
Base contains 5 carbon
- aldehyde name is pentane
- remove -e and add -al
C - C - C - C - CO-C-C
Base contains 7 carbon
- aldehyde name is heptane
- remove -e and add -one
3-heptanone
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Physical Properties of Aldehydes and
ketones
Aldehyde and ketones can only make
dipole-dipole attraction.
BP and MP are lower than alcohols ,
higher than hydrocarbons and ether
with comparable carbon numbers
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Bonding Characteristics of Aldehydes Ketones
Both aldehydes and ketones contain a carbonyl
functional group. A carbonyl group is an carbon atom
double-bonded to an oxygen atom. The structural
representation for a carbonyl group is
Carbon-oxygen (C=O) and carbon-carbon (C=C) double
bonds differ in a major way. A carbon oxygen double
bond is more polar
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Physical properties of aldehydes and
ketones.
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Nomenclature
Functional
Grou p
Su ffix
Carb oxyl
-oic acid
Ald ehyde
-al
Prefix
Example of When the Fun ction al
Grou p Has a Low er Priority
O
oxo-
3-Oxopropan oic acid
COOH
H
O
COOH
Ketone
-one
oxo-
3-Oxobutanoic acid
Alcoh ol
-ol
hydroxy-
4-Hydroxybutan oic acid HO
COOH
NH2
Amino
-amine
Su lfh ydryl -thiol
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amino-
COOH
3-Aminobutan oic acid
mercapto- 2-Mercaptoethanol
HS
OH
1-12
Name the Aldehyde
2,4-dimethylpentanal
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1. Assign the type of organic compound with following
general condensed (structural formula.
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2. Names (common/IUPAC)of following aldehydes and
ketones.
a) ____________
d) ____________
g) 2016,
____________
Chemistry 121, Winter
LA Tech
b) _______________
e) _______________
c) __________________
f) __________________
h) __________________
1-15
Nomenclature
O
O
3
4
2
3
H
3-Methylbutan al
CHO
2-Methylcycloh exanone
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3
4
1
2
H
(2E)-3,7-D imeth yl-2,6-octad ienal
(Geran ial)
1
CHO
trans -4-Hyd roxycyclohexan ecarbald ehyde
O
O
8
2-Propen al
(A crolein )
4
5
7
H
2
HO
Cyclopen tanecarb aldehyde
5-Methyl-3h exanone
O
1
1
O
Acetop hen on e
O
Benzoph enone
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3. Draw the condensed formula of
following aldehydes and ketones:
a) acetaldehyde/ b) ethyl methyl
ethanal
ketone
c) 3-methyl-2pentanone
e) 2methylbutanal
h) acetophenone
g)
benzophenone
Chemistry 121, Winter 2016, LA Tech
f) 5-methyl-3hexanone
d) isopropyl
methyl
ketone
1-17
Important Aldehydes
Methanal or formaldehyde
Ethanal or acetaldehyde
2-Propanone or acetone
2-Butanone or methyl ethyl ketone
Oil of almonds or benzaldehyde
Oil of Cinnamon or cinnamaldehyde
Oil of vanilla beans or vanillin
Mushroom flavoring or 2-octanone
Oil of lemongrass or citral:
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Preparation of Aldehydes:
Partial oxidation of primary alcohols with H2CrO4:
PCC
>
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Preapration of ketones:
Oxidation of secondary alcohols with KMnO4, or
H2CrO4 (Oxidizing agents)
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Bakelite (Polymers)
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Chemical Reactions of Aldehydes and Ketone
1) Combustion: Alkenes are very flammable and the combustion
products are carbon dioxide and water.
2) Addition Reactions: Atoms or group of atoms are added to each a
carbon oxygen double bond. Two different reactants are involved.
a) hemi-acetal or hemi-ketal formation: Addition of Alcohols: OR group of the R-OH is added to the C atom and H of the ROH is added
to O atom.
b) Aacetal or ketal formation : Substiution of hemi-acetal or -ketal
Another or second ROH is reacted in a substitution reaction to replace
the H atom of the -OH group of the hemi-acetal or hemi-ketal and water
molecule is produced.
3) Oxidation Reactions: only aldehydes are oxidized to carboxylic
acids.
4) Reduction Reactions: both aldehydes and ketones are reduced to
alcohols by taking H from the reducing agents.
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Addition reactions of als & ones
Hemiacetal or hemiketal formation
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Substitution reactions of hem-acetals/ketals
Acetal or Ketal formation
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Hemiacetal form of cyclic sugars
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4. Identify each of the following compounds
as a hemiacetal, hemiketal, acetal, or ketal:
a) ____________
d) ____________
Chemistry 121, Winter 2016, LA Tech
b) _______________
e) _______________
c) __________________
f) __________________
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Oxidation of alcohol
PCC
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Oxidation of alcohol
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5) Which alcohol would you oxidize to produce each of
the following compounds?
a)
b)
c)
d)
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Oxidation of Alcohols
• to oxidize a 1° alcohol to an aldehyde, use PCC
CrO3 Cl-
CrO3 + HCl +
N
Pyridine
N+
H
Pyridiniu m chloroch romate
(PCC)
• PCC oxidation of geraniol gives geranial
O
Geraniol
PCC
OH CH Cl
2
2
H
Geranial
Tertiary alcohols are not oxidized by either of these
reagents; they are resistant to oxidation
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6) Preparation of aldehydes and ketones
a) Control oxidation of 1ry alcohol
ry
b) Complete oxidation of 1 alcohol
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6) Preparation of adehydes
ry and ketones
c) Oxidation of 2 alcohol
ry
d) Oxidation of 3 alcohol
No Reaction
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Chemical Reactions of Aldehydes and Ketone
1) Combustion: Alkenes are very flammable and the combustion
products are carbon dioxide and water.
2) Addition Reactions: Atoms or group of atoms are added to each a
carbon oxygen double bond. Two different reactants are involved.
a) hemi-acetal or hemi-ketal formation: Addition of Alcohols: OR group of the R-OH is added to the C atom and H of the ROH is added
to O atom.
b) Aacetal or ketal formation : Substiution of hemi-acetal or -ketal
Another or second ROH is reacted in a substitution reaction to replace
the H atom of the -OH group of the hemi-acetal or hemi-ketal and water
molecule is produced.
3) Oxidation Reactions: only aldehydes are oxidized to carboxylic
acids.
4) Reduction Reactions: both aldehydes and ketones are reduced to
alcohols by taking H from the reducing agents.
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Reduction Reactions:
Both aldehydes and ketones are reduced to
alcohols by taking H from the reducing agents.
Reducing Agents
1)
2)
3)
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Reduction of als & ones compounds
to alcohols:
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Reduction of als & ones compounds
to alcohols:
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Aldehyde and Ketone Reduction: To alcohols
O
C
H2, Ni
OH
C
H
NaBH4 or LiAlH4
then H+
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7) Complete the following reductions of aldehyde and
ketones and identify the type of alcohols (1ry, 2ry and 3ry)
produced.
d)
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Reduction of als & ones compounds
to alcohols:
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Addition reactions of als & ones
Hemiacetal or hemiketal formation
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Addition reactions of als & ones
Hemiacetal or hemiketal formation
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Hemiacetal form of cyclic sugars
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Formation of Acetals and Ketals.
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8) Complete the following formation
reactions hemiacetal, hemiketal, acetal, or
ketal:
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Chemical Reactions
Oxidation of aldehyde.
Benedict's Test for aldehydes:
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Test for Urine Glucose: Benedict’s Test
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Tollen's Test:
Oxidation of aldehyde.
The commercial manufacture of silver
mirrors uses a similar process.
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9) Complete reactions of following aldehydes
and ketones
a) Tollen’s Reagent: Silver mirror test:
b)
Chemistry 121, Winter 2016, LA Tech
Benedict's test:
1-48
9) Complete reactions of following aldehydes
and ketones
c) Oxidation of aldehyde
d) Cyclic hemi-acetal formation
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Addition of HCN and H2O
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Aldol Condensation
In biological systems this reaction is
catalysed by an enzyme named aldolase.
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Keto & Enol tautomers
keto form
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enol from
1-52
Keto & Enol tautomers in sugars
aldehyde
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enol
ketone
1-53
Addition reactions of als & ones
Hemiacetal or hemiketal formation
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Formation of Acetals and Ketals.
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Hemiacetal form of cyclic sugars
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