1-1Chemistry 121, Winter 2015, 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 19, 2014: Test 1 (Chapters 12-13)
January 26 , 2015: Test 2 (Chapters 14-16)
February 13, 2015: Test 3 (Chapters 17-19)
March 2, 2015: Test 4 (Chapters 20-22)
March 3 , 2015: Make Up Exam: Chapters 12-22)
Bring Scantron Sheet 882-E
Chemistry 121(001) Winter 2015
1
1-2Chemistry 121, Winter 2015, LA Tech
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
1-5Chemistry 121, Winter 2015, 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
1-6Chemistry 121, Winter 2015, 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.
1-7Chemistry 121, Winter 2015, 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.
1-8Chemistry 121, Winter 2015, 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
1-9Chemistry 121, Winter 2015, 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
1-10Chemistry 121, Winter 2015, 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
1-12Chemistry 121, Winter 2015, LA Tech
Nomenclature
HCOOH
O
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 Prefix
Carboxyl -oic acid
Aldehyde
1-14Chemistry 121, Winter 2015, LA Tech
1. Assign the type of organic compound with following general
condensed (structural formula.
1-15Chemistry 121, Winter 2015, LA Tech
2. Names (common/IUPAC)of following aldehydes and
ketones.
a) ____________ b) _______________ c) __________________
d) ____________ e) _______________ f) __________________
g) ____________ h) __________________
1-16Chemistry 121, Winter 2015, LA Tech
Nomenclature
CHO HO CHO
Cyclopentane-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
7
8
11
223
3
4H
O
H
O
2-Methyl-cyclohexanone
5-Methyl-3-hexanone
Benzophenone Acetophenone
OO
O O
1-17Chemistry 121, Winter 2015, 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
1-18Chemistry 121, Winter 2015, LA Tech
Addition reactions of als & onesHemiacetal or hemiketal formation
1-20Chemistry 121, Winter 2015, LA Tech
4. Identify each of the following compounds as a hemiacetal, hemiketal,
acetal, or ketal:
a) ____________ b) _______________ c) __________________
d) ____________ e) _______________ f) __________________
1-21Chemistry 121, Winter 2015, LA Tech
Important AldehydesMethanal 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:
1-23Chemistry 121, Winter 2015, LA Tech
Preparation of Aldehydes:
Partial oxidation of primary alcohols with H2CrO4:
1-24Chemistry 121, Winter 2015, LA Tech
Preapration of ketones:
Oxidation of secondary alcohols with KMnO4, or H2CrO4
1-26Chemistry 121, Winter 2015, 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
1-28Chemistry 121, Winter 2015, LA Tech
5) Which alcohol would you oxidize to produce each of the
following compounds?
a)
b)
c)
d)
1-29Chemistry 121, Winter 2015, LA Tech
6) Preparation of adehydes and ketones
a) Control oxidation of 1ry alcohol
b) Complete oxidation of 1ry
alcohol
1-30Chemistry 121, Winter 2015, LA Tech
6) Preparation of adehydes and ketones
c) Oxidation of 2ry
alcohol
d) Oxidation of 3ry
alcohol
No Reaction
1-31Chemistry 121, Winter 2015, 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 : 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.
1-32Chemistry 121, Winter 2015, LA Tech
Chemical Reactions of Aldehydes and Ketone
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
1-34Chemistry 121, Winter 2015, LA Tech
Redox Reactions Reduction Reactions: both aldehydes and ketones
are reduced to alcohols by taking H from the reducing agents.
a) LiAlH4
b) NaBH4
c) H2/Ni or Pt catalysts
Oxidation Reactions: only aldehydes are oxidized to carboxylic acids.
d) Jone’s Reagent
e) AgNO3/NH4OH (silver mirror test)
f) CuSO4/Na2CO3/Citrate (Benedict’s reagent)
1-35Chemistry 121, Winter 2015, LA Tech
Aldehyde and Ketone Reduction: To alcohols
H2, Ni
NaBH4 or LiAlH4
then H+
C
OC
OH
H
1-36Chemistry 121, Winter 2015, LA Tech
7) Complete the following reductions of aldehyde and ketones and identify the type of alcohols (1ry, 2ry
and 3ry) produced.
d)
1-38Chemistry 121, Winter 2015, LA Tech
Addition reactions of als & onesHemiacetal or hemiketal formation
1-39Chemistry 121, Winter 2015, LA Tech
Addition reactions of als & onesHemiacetal or hemiketal formation
1-42Chemistry 121, Winter 2015, LA Tech
8) Complete the following formation reactions hemiacetal, hemiketal, acetal, or ketal:
1-43Chemistry 121, Winter 2015, LA Tech
Redox Reactions Reduction Reactions: both aldehydes and ketones
are reduced to alcohols by taking H from the reducing agents.
a) LiAlH4
b) NaBH4
c) H2/Ni or Pt catalysts
Oxidation Reactions: only aldehydes are oxidized to carboxylic acids.
d) Jone’s Reagent
e) AgNO3/NH4OH (silver mirror test)
f) CuSO4/Na2CO3/Citrate (Benedict’s reagent)
1-44Chemistry 121, Winter 2015, LA Tech
Chemical Reactions
Oxidation of aldehyde.
Benedict's Test for aldehydes:
1-46Chemistry 121, Winter 2015, LA Tech
Oxidation of aldehyde.
The commercial manufacture of silver mirrors uses a similar process.
Tollen's Test:
1-47Chemistry 121, Winter 2015, LA Tech
9) Complete reactions of following aldehydes
and ketones
a) Tollen’s Reagent: Silver mirror test:
b) Benedict's test:
1-48Chemistry 121, Winter 2015, LA Tech
9) Complete reactions of following aldehydes
and ketones
c) Oxidation of aldehyde
d) Cyclic hemi-acetal formation
1-50Chemistry 121, Winter 2015, LA Tech
Aldol Condensation
In biological systems this reaction is catalysed by an enzyme named aldolase.
1-53Chemistry 121, Winter 2015, LA Tech
Addition reactions of als & onesHemiacetal or hemiketal formation