General orrganic and biological chemistry structures off liffe 5th CH14 aldehydes ketones chiral molecules GOB structures 5th ed

Lecture Presentation

Chapter 14

Ketones, and Chiral Molecules

Karen C. Timberlake

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Chapter 14 Aldehydes, Ketones, and Chiral Molecules

A dermatology nurse performs many duties for the
dermatologist, including treating skin conditions, assisting in
surgeries, performing biopsies and excisions, writing
prescriptions, freezing skin lesions, and screening patients
for skin cancer.
To become a dermatology nurse, you first become a nurse or
physician assistant and then specialize in dermatology.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Chapter 14 Readiness

Core Chemistry Skills

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•
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Naming and Drawing Alkanes (12.2)
Naming Alcohols and Phenols (13.1)
Writing Equations for the Oxidation of Alcohols (13.4)

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


14.1 Aldehydes and Ketones

•

Formaldehyde is the simplest aldehyde. It is a
colorless gas with a pungent odor.

•

An aqueous solution called formalin, which
contains 40% formaldehyde, is used as a
germicide and to preserve biological specimens.

Learning Goal Identify compounds with carbonyl groups as aldehydes and ketones. Write the
IUPAC and common names for aldehydes and ketones; draw their condensed or line-angle structural
formulas.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Carbonyl Group

A carbonyl group in

•
•

an aldehyde is bonded to at least one H atom.
a ketone is bonded to two carbon groups.

Aldehydes and ketones contain
a carbonyl group that consists of
a carbon–oxygen double bond
with two groups of atoms
attached to the carbon at angles

•

of 120°.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Carbonyl Polarity

•

The oxygen atom with two lone pairs of electrons is much more
electronegative than the carbon atom.

•

The carbonyl group has a strong dipole with a partial negative
charge on the oxygen and a partial positive charge on the

δ

−

carbon.

•

The polarity of the carbonyl group strongly influences the physical

δ

+

and chemical properties of aldehydes and ketones.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Naming Aldehydes

In the IUPAC system,

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•
•

an aldehyde is named by replacing the e of the corresponding alkane name with al.
no number is needed for the aldehyde group because it always appears at the end of the chain.
aldehydes with carbon chains of one to four carbons are often referred to by their common names,
which end in aldehyde.

Core Chemistry Skill Naming Aldehydes and Ketones

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.

Naming Aldehydes

The IUPAC system names the aldehyde of benzene as benzaldehyde.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Guide to Naming Aldehydes

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Study Check

Give the IUPAC name for the following aldehyde:

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solution

Give the IUPAC name for the following aldehyde:

ANALYZE

Given

THE

condensed structural

PROBLEM

STEP 1

IUPAC name

formula of aldehyde

Name the longest carbon chain by replacing the e in the alkane name with al.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

Need

© 2016 Pearson Education, Inc.


Solution

Give the IUPAC name for the following aldehyde:

STEP 2

Name and number any substituents by counting the carbonyl group as carbon 1.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Naming Ketones

To name ketones using common names,

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•

the alkyl groups bonded to the carbonyl group are named as substituents.
the substituents are listed alphabetically, followed by ketone.

Acetone, another name for propanone, has been retained by the IUPAC system.

Propanone
(dimethyl ketone, acetone)

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Naming Ketones

In the IUPAC system,

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•

the name of a ketone is obtained by replacing the e in the alkane name with one.
chains with five carbon atoms or more are numbered from the end nearer the carbonyl group.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Naming Cyclic Ketones

For cyclic ketones,

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•
•

the prefix cyclo is used in front of the ketone name.
any substituent is located by numbering the ring starting with the carbonyl carbon as carbon 1.

the ring is numbered in the direction to give substituents the lowest possible numbers.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Guide to Naming Ketones

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Study Check

Give the IUPAC name for the following ketone:

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solution

Give the IUPAC name for the following ketone:

ANALYZE

Given

THE

condensed structural

PROBLEM

STEP 1

IUPAC name

formula of ketone

Name the longest carbon chain by replacing the e in the alkane name with one.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

Need

© 2016 Pearson Education, Inc.


Solution

Give the IUPAC name for the following ketone:

STEP 2

Number the carbon chain starting from the end nearer the carbonyl group and indicate it
location.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solution

Give the IUPAC name for the following ketone:

STEP 3

Name and number any substituents on the carbon chain.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Naming Compounds: Two Functional Groups

According to IUPAC rules for nomenclature, the more oxidized group will take priority in naming a
compound with more than one functional group.

•

Table 14.1 lists the priorities for the functional groups we have studied and the names of the
functional groups as substituents.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Naming Compounds: Two Functional Groups

•

The functional group that is highest on the list is named as the compound, and any group lower
on the list is named as a substituent.

•

Examples are given for naming an alcohol, a ketone, and an aldehyde.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Chemistry Link to Health:
Important Aldehydes and Ketones

Formalin, a 40% formaldehyde aqueous solution,

•
•

is used as a germicide and to preserve biological specimens.
is used in industry as a reactant in the synthesis of polymers used to make fabrics, insulation
materials, carpeting, pressed wood products such as plywood,

and plastics

for kitchen counters.

Exposure to fumes can irritate
the eyes, nose, and upper
respiratory tract and cause skin rashes,
headaches, dizziness, and general fatigue.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Chemistry Link to Health:
Important Aldehydes and Ketones

•

The simplest ketone, known as acetone or propanone (dimethyl ketone), is a colorless liquid with a
mild odor that has wide use as a solvent in cleaning fluids, paint and nail polish removers, and rubber
cement.

•

In the body, acetone may
be produced in uncontrolled
diabetes, fasting, and
high-protein diets when large
amounts of fats are metabolized
for energy.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Chemistry Link to Health:
Important Aldehydes and Ketones

Several naturally occurring aromatic aldehydes are used to flavor
food and as fragrances in perfumes.

•
•
•

Benzaldehyde is found in almonds.

Vanillin is found in vanilla beans.
Cinnamaldehyde is found in cinnamon.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.