1
Carbonyl Compounds

• Aldehydes, Ketones, Acids, Esters, and Amides
  Chapters 17-19

2
Goals End of Organic Section

• Nomenclature for (5) carbonyl compounds
• Basic nomenclature for mixed compounds
• Physical properties of these compounds
• Importance of these materials, biological
  significance
• Some basic reaction mechanisms throughout
• We will stop periodically to work on naming and
  drawing download sheets tonight

3
Aldehydes and Ketones

• Each contains a CO (carbonyl) group.
• Aldehyde Contains a carbonyl group bonded to a
  hydrogen in formaldehyde, the simplest aldehyde,
  the carbonyl group is bonded to two hydrogens.
• Ketone Contains a carbonyl group bonded to two
  carbon atoms.

Aldehyde naming
Ketone naming

• Drop the last e and replace it with al.
• You dont need to number the carbonyl group,
  since it will automatically be at carbon 1.

• Drop the last e and replace it with one.
• You DO need to number the group in a ketone since
  it can occur on any interior carbon.

4
Aldehydes and Ketones
For simple ketones you can name R groups and add
ketone
5
Mixed with Alkenes
More to follow
6
Physical Properties Common to all compounds in
these Chapters

• A CO bond is polar, with oxygen bearing a
  partial negative charge and carbon bearing a
  partial positive charge.
• Therefore, all carbonyl compounds are polar
  molecules.
• The polarity of a carbonyl group.

7
Physical Properties

• In liquid aldehydes and ketones, there are weak
  intermolecular attractions between the partial
  positive charge on the carbonyl carbon of one
  molecule and the partial negative charge on the
  carbonyl oxygen of another molecule.
• No hydrogen bonding is possible between aldehyde
  or ketone molecules.
• Aldehydes and ketones have lower boiling points
  than alcohols and carboxylic acids, compounds in
  which there is hydrogen bonding between
  molecules.

8
Physical Properties

• Formaldehyde, acetaldehyde, and acetone are
  infinitely soluble in water.
• Aldehydes and ketones become less soluble in
  water as the hydrocarbon portion of the molecule
  increases in size.

9
What leads to the Solubility of small aldehydes
and ketones?
p. 462
10
Some naturally occurring Aldehydes and Ketones
p. 461
11
Carboxylic Acids

• Carboxylic acid A compound containing a -COOH
  (carboxyl carbonyl hydroxyl) group.
• In a condensed structural formula, a carboxyl
  group may also be written -CO2H.

Naming
Drop the last e and replace it with oic
acid. You do not need to number the carbon since
the carboxyl group will automatically be at
carbon 1.
12
Carboxylic Acids
13
Electron Density
Fig. 18-1, p. 478
14
High Boiling points via H-bonding
p. 478
15
Physical Properties
Notice the solubility of acids versus other
functional compounds. Why?
Table 18-2, p. 479
16
Fatty Acids

• Fatty acids Long chain carboxylic acids derived
  from animal fats, vegetable oils, or
  phospholipids of biological membranes.
• More than 500 have been isolated from various
  cells and tissues.
• Most have between 12 and 20 carbons in an
  unbranched chain.
• In most unsaturated fatty acids, the cis isomer
  predominates trans isomers are rare.

17
Common Acids
Table 18-1, p. 477
18
Common Acids
Why do saturated fats have a higher MP?
Table 18-3, p. 479
19
Fatty Acids

• Saturated fatty acids are solids at room
  temperature.
• The regular nature of their hydrocarbon chains
  allows them to pack together in such a way as to
  maximize interactions (by which type of forces?)
  between their chains.

20
Fatty Acids

• In contrast, all unsaturated fatty acids are
  liquids at room temperature because the cis
  double bonds interrupt the regular packing of
  their hydrocarbon chains.

21
Acidity of Carboxylic Acids

• Substituents of high electronegativity,
  especially -OH, -Cl, and -NH3, near the carboxyl
  group increase the acidity of carboxylic acids.
  Why? Think back to basicity of amines.

Which is the stronger acid and why?
You should probably first write the reaction of
what happens when you place an acid in water
22
Soaps
Fig. 18-2, p. 483
23
Soaps
Fig. 18-3, p. 483
24
Carboxyl Derivatives

• We can now look at a couple of classes of
  compounds derived from carboxylic acids esters,
  and amides.
• Each is related to a carboxyl group by loss of
  H2O.

25
Carboxylic Ester

• Carboxylic ester A derivative of a carboxylic
  acid in which the H of the carboxyl group is
  replaced by a carbon group. Simply calling these
  esters is acceptable. A cyclic ester is called a
  lactone.

Naming Esters
1. Name the alkyl group (R) which is attached to
the oxygen. 2. Name the group on the other side
of the carboxyl group. Drop the last e and
change it to oate.
26
Ester Naming
27
Esterification

• In an esterification reaction, the alcohol adds
  to the carbonyl group of the carboxylic acid to
  form a tetrahedral carbonyl addition
  intermediate.
• The intermediate then loses H2O to give an ester.
  See if you can figure out the rest.

Mechanism time!
Propose a mechanism when you place propanoic acid
and ethanol in the presence of an acid and heat.
28
Amides

• The functional group of an amide is a carbonyl
  group bonded to a nitrogen atom. (where
  are these found?)
• To name an amide, drop the usual e and add
  -amide.
• If the amide nitrogen is also bonded to an alkyl
  or aryl group, name the group and show its
  location on nitrogen by N- two alkyl or aryl
  groups by N,N-di- (or a combination).

29
Amide naming
30
Cyclic Amides

• A cyclic amide is called a lactam.
• The penicillins are referred to as b-lactam
  antibiotics.

b-lactam
31
Important Amides
32
Preparation of Amides

• In principle, we can form an amide by treating a
  carboxylic acid with an amine and removing -OH
  from the acid and an -H from the amine.
• In practice what occurs if the two are mixed is
  an acid-base reaction to form an ammonium salt.
• If this salt is heated to a high enough
  temperature, water is eliminated and an amide
  forms.

33
Step-Growth Polymerization

• Step-growth polymers are formed by reaction
  between two molecules, each of which contains two
  functional groups. Each new bond is created in a
  separate step.
• in this section, we will only discuss a couple of
  well-known examples Kevlar and nylon-66, both
  polyamides.
• You are aware already of polyesters right?

34
Polyamides

• Nylon-66 was the first purely synthetic fiber.
• It is synthesized from two six-carbon monomers.

35
Polyamides

• The polyaromatic amide known as Kevlar is made
  from an aromatic dicarboxylic acid and an
  aromatic diamine.

36
What about Mixed Systems?
This list represents a sampling of the functional
groups it is only 10 complete These are the
most common, however.
37
Examples
38
More Examples Alkynes and Alkenes involved
39
Organic Chemistry the end

• You should pretty much know it all for the exam
  coming up.

Up next - Biochemistry