Chemistry 121(01) Winter 2014
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 9:00 am - 11:00 am;
TR 9:00 - 10:00 am & 1:00-2:00 pm.
December 20, Test 1 (Chapters 12-13)
January 27 Test 2 (Chapters 14-16)
February 14 Test 3 (Chapters 17-19)
February 26, Test 4 (Chapters 20-22)
February 27, 2014, Make Up Exam:
Bring Scantron Sheet 882-E
Chemistry 121, Winter 2014, LA Tech
1-1
Chapter 15: Aldehyde and Ketones
15.1 The Carbonyl Group, 469
15.2 Compounds Containing a Carbonyl Group, 470
15.3 The Aldehyde and Ketone Functional Groups, 471
15.4 Nomenclature for Aldehydes, 472
15.5 Nomenclature for Ketones, 474
15.6 Isomerism for Aldehydes and Ketones, 476
15.7 Selected Common Aldehydes and Ketones, 476
15.8 Physical Properties of Aldehydes and Ketones, 479
15.9 Preparation of Aldehydes and Ketones, 481
15.10 Oxidation and Reduction of Aldehydes and Ketones,
482
15.11 Reaction of Aldehydes and Ketones with Alcohols, 486
15.12 Formaldehyde-Based Polymers, 491
15.13 Sulfur-Containing Carbonyl Groups, 492
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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.
Chemistry 121, Winter 2014, LA Tech
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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
Chemistry 121, Winter 2014, LA Tech
amino-
COOH
3-Aminobutan oic acid
mercapto- 2-Mercaptoethanol
HS
OH
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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) 2014,
____________
Chemistry 121, Winter
LA Tech
b) _______________
e) _______________
c) __________________
f) __________________
h) __________________
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Nomenclature
O
O
3
4
2
3
H
3-Methylbutan al
CHO
2-Methylcycloh exanone
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6
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 2014, LA Tech
f) 5-methyl-3hexanone
d) isopropyl
methyl
ketone
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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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4. Identify each of the following compounds
as a hemiacetal, hemiketal, acetal, or ketal:
a) ____________
d) ____________
Chemistry 121, Winter 2014, LA Tech
b) _______________
e) _______________
c) __________________
f) __________________
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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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Bakelite
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Preapration of Aldehydes:
Partial oxidation of primary alcohols with H2CrO4:
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Preapration of ketones:
Oxidation of secondary alcohols with KMnO4, or
H2CrO4
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Oxidation of alcohol
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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 adehydes 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 : 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.
O: both reactants (H-X (X= Cl, OH)) and the alkene need to be
asymmetric
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 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 2014, LA Tech
Benedict's test:
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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
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Keto & Enol tautomers in sugars
aldehyde
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enol
ketone
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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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