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Introduction to Organic Chemistry and BiochemistryIntroduction to Organic Chemistry and Biochemistry Instructor Dr. Upali Siriwardane (Ph.D. Ohio State) E-mail: upali@chem.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 16, Test 1 (Chapters 12-13)January 20 Test 2 (Chapters 14-16)February 6 (Chapters 17-19)February 27, (Chapters 20-22)February 28, 2012, Make Up Exam:Bring Scantron Sheet 882-E

Chemistry 121(01) Winter 2012

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Chapter 15: Aldehyde and KetonesChapter 15: Aldehyde and Ketones

SectionsSections

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Chapter 15: Aldehyde and KetonesChapter 15: Aldehyde and Ketones15.1 The Carbonyl Group15.1 The Carbonyl Group15.2 Structure of Aldehydes and Ketones15.2 Structure of Aldehydes and Ketones15.3 Nomenclature for Aldehydes15.3 Nomenclature for Aldehydes15.4 Nomenclature for Ketones15.4 Nomenclature for Ketones15.5 Isomerism for Aldehydes and Ketones15.5 Isomerism for Aldehydes and Ketones15.6 Selected Common Aldehydes and Ketones15.6 Selected Common Aldehydes and Ketones15.7 Physical Properties of Aldehydes and Ketones15.7 Physical Properties of Aldehydes and Ketones15.8 Preparation of Aldehydes and Ketones15.8 Preparation of Aldehydes and Ketones15.9 Oxidation and Reduction of Aldehydes and Ketones15.9 Oxidation and Reduction of Aldehydes and Ketones

15.10 Reaction of Aldehydes and Ketones with Alcohols15.10 Reaction of Aldehydes and Ketones with Alcohols

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Carbonyl GroupCarbonyl Group

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StructureStructure• the functional group of an aldehyde is a carbonyl group

bonded to a H atom • the functional group of a ketone is a carbonyl group

bonded to two carbon atoms

Propanone(Acetone)

Ethanal(Acetaldehyde)

Methanal(Formaldehyde)

O O O

CH3CHHCH CH3CCH3

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IUPAC Nomenclature of Aldehyde and IUPAC Nomenclature of Aldehyde and KetonesKetones

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 -alal ending.

Ketones -RCOR’ use -oneone ending.

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ExampleExample

C - C - C - C - CHO

Base contains 5 carbon- aldehyde name is pentane- remove -e-e and add -al -al

C - C - C - C - CO-C-C

Base contains 7 carbon- aldehyde name is heptane- remove -e-e and add -one -one3-heptanone

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NomenclatureNomenclature

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

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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

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Name the AldehydeName the Aldehyde

2,4-dimethylpentanal

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Common NamesCommon NamesAldehydes: Fomaldehyde: HCHO

Acetaldehyde: CH3CHO

Propionaldehyde: CH3CH2CHO

Butyraldehyde: CH3CH2CH2CHO

Valeraldehyde: CH3CH2CH2CH2CHO

Ketones:Ketones:

Acetone: CH3COCH3

Methyl ethyl ketone CH3CH2COCH3 Butyl propyl ketone

CH3CH2CH2CH2COCH2CH2CH3

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Simplest AldehydeSimplest Aldehyde

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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:

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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 ketonesPreapration 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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Physical properties of aldehydes and Physical properties of aldehydes and ketones.ketones.

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Chemical ReactionsChemical Reactions

Oxidation of aldehyde.

Benedict's Test for aldehydes:

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Test for Urine Glucose: Benedict’s TestTest for Urine Glucose: Benedict’s Test

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Oxidation of aldehyde.

The commercial manufacture of silver mirrors uses a similar process.

Tollen's Test:Tollen's Test:

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Reduction of als & ones compounds Reduction of als & ones compounds to alcohols:to alcohols:

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Addition reactions of als & onesAddition reactions of als & onesHemiacetal or hemiketal formation

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Hemiacetal form of cyclic sugarsHemiacetal form of cyclic sugars

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Formation of Acetals and Ketals.Formation of Acetals and Ketals.

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Addition of HCN and HAddition of HCN and H22OO

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Aldol CondensationAldol Condensation

In biological systems this reaction is catalysed by an enzyme named aldolase.

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Keto & Enol tautomers

keto form enol from

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Keto & Enol tautomers in sugars

aldehyde enol ketone