Ch 10: Chapter Outline

1
Ch 10 Chapter Outline
10.1 Carboxylic Acids 10.2 Phenols 10.3
Carboxylic Acids and Phenols as Weak Organic
Acids 10.4 Other Reactions of Carboxylic Acids
10.5 Oxidation of Phenols
10.6 Amines 10.7 Amines as Weak Organic
Bases 10.8 Amides 10.9 Stereoisomers
2
10.1 Carboxylic Acids
Some carboxylic acids have common names.
ethanoic acid acetic acid (found in
vinegar)
methanoic acid formic acid
3
(No Transcript)
4
Naming Carboxylic Acids

• When naming a carboxylic acid according to the
  IUPAC rules, the parent is the longest continuous
  carbon chain that includes the carboxyl group.
• Numbering begins at the carboxyl carbon, and
  alkyl groups are identified by name, position,
  and number of appearances.
• IUPAC names for carboxylic acid main chains are
  formed by dropping the final e on the name of
  the corresponding alkanes and adding oic acid.

5
Exercise
Give the IUPAC name of each carboxylic acid.
6
Exercise

• Draw each molecule. Hint When named as a
  substituent, -OH is hydroxyl -OH is taken to be
  a branch. The COOH takes priority over the OH
  group.
• 4-hydroxybutanoic acid
• 2-bromopropanoic acid
• 4-chlorohexanoic acid

7
Physical Properties of CAs

• Compared to other organic compounds with a
  similar molecular weight, carboxylic acids have
  relatively high boiling points due to their
  ability to form more more hydrogen bonds with one
  another.
• The ability to form hydrogen bonds in these
  groups CO, C-O, and O-H, gives small carboxylic
  acids a significant water solubility.
• As we have seen before, an increasing number of
  carbon atoms leads to a reduction in water
  solubility.

8
In the simplest phenol, named phenol, the -OH
group is the only group attached to a benzene
ring.When substituents are added to this
molecule, the carbon atom carrying the -OH is
designated as carbon 1.
10.2 Phenols
9
(No Transcript)
10
10.3 Carboxylic Acids and Phenols are Weak
Organic Acids

• Having a Ka of 1.8 x 10-5 (pKa 4.74), acetic
  acid is a weak acid.

Phenols are weaker acids than CAs pKa is about
10.
11
A biochemical significance of the form of the
carboxylic acid (as a carboxylate anion at
physiological pHs) relates to fatty acids.At
physiological pHs, fatty acids exist as
amphipathic ions that can mix with water, to some
extent.In general, carboxylate anions with 12 or
more carbon atoms, like palmitate ion, are
amphipathic compounds, while those with fewer
than 12 carbon atoms are water soluble.
12
Naming Carboxylate Ions

• To name a carboxylate ion, the ending on the name
  (IUPAC or common) of the related carboxylic acid
  is changed from ic acid to ate.
• Palmitic acid becomes palmitate ion, and acetic
  acid becomes acetate ion.

13
Rxn of phenol with NaOH

• Carboxylate ions are more soluble in water than
  carboxylic acids.
• Phenoxide ions are more soluble in water than
  phenols.

14
(No Transcript)
15
10.4 - Reactions of CAs to make Esters -
Hydrolysis of Esters
16
Naming Esters
17
Exercise
Draw the product of the reaction. Name the
ester that forms. Strategy Ester formation
is a double replacement reaction, and the product
ester contains a carboxylic acid residue and an
alcohol residue. Each of these residues is
considered when assigning a name to the ester.
18

• Ester formation is a reversible process.
• In hydrolysis reactions, esters are broken apart
  by water to form a carboxylic acid plus an
  alcohol.
• Esters can also be hydrolyzed under basic
  conditions.

19
Decarboxylation

• Decarboxylation is a decomposition reaction that
  results in the loss of carbon dioxide (CO2) from
  a beta-keto and alpha-keto carboxylic acid.

20
Examples of Decarboxylation rxn
21
Exercise
Draw the products of each decarboxylation
reaction. Strategy In a decarboxylation
reaction, CO2 is released from a carboxylic acid
reactant.
22
10.5 Oxidation of Phenols
23
Exercise

• Draw the product of the reaction between KOH
  and
• butanoic acid
• p-bromophenol

24
10.6 Amines

• Amines are classified based on the number of
  carbon atoms directly attached to the nitrogen
  atom.
• primary (1?) - only one carbon atom attached to
  the amine nitrogen atom
• secondary (2?) - two attached carbon atoms
• tertiary (3?) - three attached carbon atoms
• quaternary (4?) ammonium ions - four carbon atoms
  are directly attached to the nitrogen atom and
  the nitrogen carries a 1 charge.

25
Naming Amines

• To name a 1?, 2?, or 3? amine using IUPAC rules,
  the parent, the longest chain of carbon atoms
  attached to the amine nitrogen atom, is numbered
  from the end nearer the point of attachment of
  the nitrogen.
• The parent chains of amines are named by dropping
  e from the name of the corresponding
  hydrocarbon and adding amine.

26
Naming Amines

• If an amine is 2? or 3?, the carbon-containing
  groups attached to the nitrogen atom that are not
  part of the parent chain are substituents and N
  is used to indicate their location (N-methyl,
  N,N-diethyl, etc.).
• Simple amines, those with a relatively few number
  of carbon atoms, are often identified by common
  names by placing amine after the names of the
  groups attached to the nitrogen.
• methylamine CH3NH2

27
(No Transcript)
28
(No Transcript)
29
Exercise
Match each IUPAC and common name to the correct
structural formula
30
Heterocyclic amines
31

• 1? and 2? amines form hydrogen bonds with like
  amines.
• 3? amines do not form hydrogen bonds among
  themselves why?

32
10.7 Amines as Weak Organic Bases (Which is the
H acceptor?)
33
Rxn of amine with acids
A strong acid converts an amine into its
conjugate acid.
34
10.8 Amides and Rxn of Amides
35
Formation of Amide
Hydrolysis of Amide
36
What functional groups are present on these
molecules?
37
10.9 Stereoisomers

• Members of one class of stereoisomers are called
  enantiomers.
• Enantiomers are nonsuperimposable mirror image
  forms of a molecule.

38
(No Transcript)
39
The Chirality of an object

• The term chiral is used to describe objects that
  cannot be superimposed on their mirror image.
• Example Your hands are chiral because your left
  hand is not superimposable on your right hand,
  its mirror image. (Try it!)

40
Exercise
Use an asterisk to label the chiral carbon atom
in each molecule.
41
(No Transcript)