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1-1Chemistry 121, Winter 2016, LA Tech
Introduction to Organic Chemistry and Biochemistry
Instructor Dr. Upali Siriwardane (Ph.D. Ohio State)
E-mail: [email protected]
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
1
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1-2Chemistry 121, Winter 2016, LA Tech
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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1-3Chemistry 121, Winter 2016, LA Tech
Carbonyl Group
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1-4Chemistry 121, Winter 2016, LA Tech
Simplest Aldehyde
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1-5Chemistry 121, Winter 2016, LA Tech
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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1-6Chemistry 121, Winter 2016, LA Tech
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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1-7Chemistry 121, Winter 2016, LA Tech
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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1-8Chemistry 121, Winter 2016, LA Tech
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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1-9Chemistry 121, Winter 2016, LA Tech
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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1-10Chemistry 121, Winter 2016, LA Tech
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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1-11Chemistry 121, Winter 2016, LA Tech
Physical properties of aldehydes and ketones.
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1-12Chemistry 121, Winter 2016, LA Tech
Nomenclature
H COOHO
COOHO
COOHHO
OHHS
COOHNH2
-al oxo-
Ketone -one oxo-
Alcohol -ol hydroxy-
Amino -amine amino-
3-Oxopropanoic acid
3-Oxobutanoic acid
4-Hydroxybutanoic acid
3-Aminobutanoic acid
Example of When the FunctionalGroup Has a Lower Priority
Sulfhydryl -thiol mercapto- 2-Mercaptoethanol
Functional Group Suffix PrefixCarboxyl -oic acidAldehyde
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1-13Chemistry 121, Winter 2016, LA Tech
Name the Aldehyde
2,4-dimethylpentanal
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1-14Chemistry 121, Winter 2016, LA Tech
1. Assign the type of organic compound with following general
condensed (structural formula.
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1-15Chemistry 121, Winter 2016, LA Tech
2. Names (common/IUPAC)of following aldehydes and
ketones.
a) ____________ b) _______________ c) __________________
d) ____________ e) _______________ f) __________________
g) ____________ h) __________________
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1-16Chemistry 121, Winter 2016, LA Tech
Nomenclature
CHO HO CHOCyclopentane-carbaldehyde
trans-4-Hydroxycyclo-hexanecarbaldehyde
14
3-Methylbutanal 2-Propenal(Acrolein)
H
O
(2E)-3,7-Dimethyl-2,6-octadienal(Geranial)
1
2
3
4
5
6
78
1122
33
4 H
O
H
O
2-Methyl-cyclohexanone
5-Methyl-3-hexanone
Benzophenone Acetophenone
OO
O O
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1-17Chemistry 121, Winter 2016, LA Tech
3. Draw the condensed formula of
following aldehydes and ketones:
a) acetaldehyde/ ethanal
b) ethyl methyl ketone
c) 3-methyl-2- pentanone
d) isopropyl methyl ketone
e) 2-methylbutanal
f) 5-methyl-3- hexanone
g) benzophenone
h) acetophenone
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1-18Chemistry 121, Winter 2016, LA Tech
Important AldehydesMethanal or formaldehydeEthanal or acetaldehyde2-Propanone or acetone2-Butanone or methyl ethyl ketoneOil of almonds or benzaldehydeOil of Cinnamon or cinnamaldehyde Oil of vanilla beans or vanillinMushroom flavoring or 2-octanoneOil of lemongrass or citral:
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1-19Chemistry 121, Winter 2016, LA Tech
Preparation of Aldehydes: Partial oxidation of primary alcohols with H2CrO4:
PCC
>
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1-20Chemistry 121, Winter 2016, LA Tech
Preapration of ketones: Oxidation of secondary alcohols with KMnO4, or
H2CrO4 (Oxidizing agents)
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1-21Chemistry 121, Winter 2016, LA Tech
Bakelite (Polymers)
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1-22Chemistry 121, Winter 2016, LA Tech
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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1-23Chemistry 121, Winter 2016, LA Tech
Addition reactions of als & onesHemiacetal or hemiketal formation
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1-24Chemistry 121, Winter 2016, LA Tech
Substitution reactions of hem-acetals/ketalsAcetal or Ketal formation
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1-25Chemistry 121, Winter 2016, LA Tech
Hemiacetal form of cyclic sugars
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1-26Chemistry 121, Winter 2016, LA Tech
4. Identify each of the following compounds as a hemiacetal, hemiketal,
acetal, or ketal:
a) ____________ b) _______________ c) __________________
d) ____________ e) _______________ f) __________________
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1-27Chemistry 121, Winter 2016, LA Tech
Oxidation of alcohol
PCC
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1-28Chemistry 121, Winter 2016, LA Tech
Oxidation of alcohol
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1-29Chemistry 121, Winter 2016, LA Tech
5) Which alcohol would you oxidize to produce each of the
following compounds?
a)
b)
c)
d)
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1-30Chemistry 121, Winter 2016, LA Tech
Oxidation of Alcohols
• to oxidize a 1° alcohol to an aldehyde, use PCC
• PCC oxidation of geraniol gives geranial
Tertiary alcohols are not oxidized by either of these reagents; they are resistant to oxidation
CrO3 HClN N
H
CrO3Cl-
Pyridinium chlorochromate (PCC)
Pyridine
+ ++
OHPCCCH2Cl2 H
O
Geraniol Geranial
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1-31Chemistry 121, Winter 2016, LA Tech
6) Preparation of aldehydes and ketones
a) Control oxidation of 1ry alcohol
b) Complete oxidation of 1ry
alcohol
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1-32Chemistry 121, Winter 2016, LA Tech
6) Preparation of adehydes and ketones
c) Oxidation of 2ry
alcohol
d) Oxidation of 3ry
alcohol
No Reaction
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1-33Chemistry 121, Winter 2016, LA Tech
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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1-34Chemistry 121, Winter 2016, LA Tech
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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1-35Chemistry 121, Winter 2016, LA Tech
Reduction of als & ones compounds to alcohols:
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1-36Chemistry 121, Winter 2016, LA Tech
Reduction of als & ones compounds to alcohols:
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1-37Chemistry 121, Winter 2016, LA Tech
Aldehyde and Ketone Reduction: To alcohols
H2, Ni
NaBH4 or LiAlH4
then H+
CO
COH
H
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1-38Chemistry 121, Winter 2016, LA Tech
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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1-39Chemistry 121, Winter 2016, LA Tech
Reduction of als & ones compounds to alcohols:
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1-40Chemistry 121, Winter 2016, LA Tech
Addition reactions of als & onesHemiacetal or hemiketal formation
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1-41Chemistry 121, Winter 2016, LA Tech
Addition reactions of als & onesHemiacetal or hemiketal formation
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1-42Chemistry 121, Winter 2016, LA Tech
Hemiacetal form of cyclic sugars
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1-43Chemistry 121, Winter 2016, LA Tech
Formation of Acetals and Ketals.
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1-44Chemistry 121, Winter 2016, LA Tech
8) Complete the following formation reactions hemiacetal, hemiketal, acetal, or ketal:
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1-45Chemistry 121, Winter 2016, LA Tech
Chemical ReactionsOxidation of aldehyde. Benedict's Test for aldehydes:
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1-46Chemistry 121, Winter 2016, LA Tech
Test for Urine Glucose: Benedict’s Test
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1-47Chemistry 121, Winter 2016, LA Tech
Oxidation of aldehyde.The commercial manufacture of silver
mirrors uses a similar process.
Tollen's Test:
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1-48Chemistry 121, Winter 2016, LA Tech
9) Complete reactions of following aldehydes
and ketones
a) Tollen’s Reagent: Silver mirror test:
b) Benedict's test:
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1-49Chemistry 121, Winter 2016, LA Tech
9) Complete reactions of following aldehydes
and ketones
c) Oxidation of aldehyde
d) Cyclic hemi-acetal formation
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1-50Chemistry 121, Winter 2016, LA Tech
Addition of HCN and H2O
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1-51Chemistry 121, Winter 2016, LA Tech
Aldol Condensation
In biological systems this reaction is catalysed by an enzyme named aldolase.
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1-52Chemistry 121, Winter 2016, LA Tech
Keto & Enol tautomersketo form enol from
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1-53Chemistry 121, Winter 2016, LA Tech
Keto & Enol tautomers in sugars
aldehyde enol ketone
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1-54Chemistry 121, Winter 2016, LA Tech
Addition reactions of als & onesHemiacetal or hemiketal formation
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1-55Chemistry 121, Winter 2016, LA Tech
Formation of Acetals and Ketals.
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1-56Chemistry 121, Winter 2016, LA Tech
Hemiacetal form of cyclic sugars