Chapter 11 Outline

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Chapter 11 Outline
11.1 Alcohols, Ethers, and Related Compounds 11.2
and 11.3 Preparation and Reactions 11.4
Aldehydes and Ketones 11.5 Oxidation of Aldehydes
11.6 Reduction of Aldehydes and Ketones 11.7
Reactions of Alcohols with Aldehydes and Ketones
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11.1
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Examples of complex org. cpds.
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Are these org. cpds?
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11.1 Alcohols, Ethers, and Related Compounds
Naming Alcohols

• When the IUPAC rules are used to name an alcohol,
  the main chain (the longest continuous carbon
  chain carrying the -OH group) is numbered from
  the end nearer the -OH and named by replacing the
  e ending on the name of the corresponding
  hydrocarbon by adding ol (i.e. methane to
  methanol).
• When a parent chain contains more than two carbon
  atoms, the position of the -OH group must be
  specified with a number.
• Any alkyl groups (branches) attached to the main
  chain are identified by name, position, and
  number of appearances.

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Alcohols
Thiols
Ethers
Sulfides
Disulfides
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Classification of alcohols 1?, 2?, and 3?
Alcohols

• Primary alcohol (1?) - the C atom carrying the
  -OH group is attached to one other C atom.
• Secondary alcohol (2?) - the C atom carrying
  the -OH group is attached to two other C atoms.
• Tertiary alcohol (3?) - the C atom carrying the
  -OH group is attached to three other C atoms.

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H-binding in alcohols Compared to hydrocarbons
with a similar molecular weight, alcohols have
relatively high boiling points.
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• The boiling points of ethers, thiols, sulfides,
  and disulfides are much lower than those of
  alcohols with similar molecular weights, because
  none of these compounds are able to form hydrogen
  bonds to like molecules.
• Ether molecules are slightly polar as a
  consequence of the C-O-C linkage, but the
  dipole-dipole attractions that occur between
  ether molecules are not strong enough to raise
  boiling points much above those of similar sized
  hydrocarbons.

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Example
Which of the following molecules can form
hydrogen bonds to another molecule of the same
type?
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Exercise
Predict which molecule has the higher boiling
point?
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Alcohols can be prepared using a nucleophilic
substitution reaction, in which an electron-rich
atom or group of atoms, called a nucleophile,
replaces a leaving group, an easily replaced atom
or group of atoms. Chlorine, bromine, and iodine
are common leaving groups used in organic
chemistry.
11.2 and 11.3 Preparation of alcohols and their
reactions
(See next slide for reaction to form alcohols)
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Nucleophilic Substitution rxns.
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Exercise
Draw the organic product of each nucleophilic
substitution reaction.
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Rxn for making alcohols from alkenes
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11.3 Oxidation of alcohols
Oxidation gaining more Os, losing
Hs Reduction gaining more Hs, losing Os
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Exercise
Draw the product expected from each reaction.
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Exercise
In Chapter 15 we will study the citric acid
cycle, a series of reactions involved in making
compounds that can be used in a separate process
to manufacture an energy-rich compound called
ATP. A reaction early in the citric acid cycle
involves the oxidation of an alcohol. Of the two
reactants shown below (each is a reactant
somewhere in the cycle), which can be oxidized?
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Dehydration rxn of alcohols Alcohols -----gt
alkenes (lost of OH and H or H2O ---gt get a
double bond on the product)
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The oxidation of thiols produces a different type
of product than obtained from the oxidation of
alcohols. On treatment with the oxidizing agent
I2, two thiol molecules combine to form a
disulfide. The loss of hydrogen atom by each
thiol is evidence that oxidation has taken place.
Oxidation of thiols by I2
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11.4 Aldehydes and Ketones Naming Aldehydes
and Ketones

• When naming aldehydes and ketones according to
  the IUPAC rules, the carbonyl (CO) must be part
  of the main chain, which is numbered from the end
  nearer this CO group.
• Since the carbonyl carbon atom of an aldehyde is
  always in position number 1, its position is not
  specified in the name.
• For ketones, however, the position of the
  carbonyl carbon is given, unless the molecule is
  small enough that there is no question as to
  where the CO is located.
• Parent chains are named by dropping the final e
  from the name of the corresponding hydrocarbon
  and adding al for aldehydes or one for
  ketones.

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IUPAC names vs. common names of aldehydes and
ketones
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General physical properties of aldehydes and
ketones

• Aldehydes and ketones have much lower boiling
  points than alcohols with a similar molecular
  weight.
• The differences in boiling points is due to the
  fact that alcohols can form hydrogen bonds while
  aldehydes and ketones cannot.
• The CO is slightly polar, which allows an
  aldehyde or ketone to interact with one another
  through dipole-dipole forces.

The polarity of the carbonyl group and its
ability to form hydrogen bonds with water
molecules allows small aldehydes and ketones to
be highly water soluble (like dissolves like).
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11.5 Oxidation of Aldehydes
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11.6 Reduction of Aldehydes and Ketones
Reactant Product (more
Os, less Hs) (more Hs, less Os
gaining more Hs)
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Examples
Draw the alcohol product expected from each
reduction reaction.
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Exercises
What is the organic reactant that would undergo
the reaction below to give the product shown in
each reaction?
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11.7 Reactions of Alcohols with Aldehydes and
Ketones (Hemiacetal and Hemiketals)
When an aldehyde or ketone is reacted with one
alcohol molecule a hemiacetal is
formed. (Hemiacetals formed from ketones are
also known as hemiketals). A hemiacetal
consists of a carbon atom that is attached to
both -OH and -OC.
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These are hemiacetals and hemiketals! How do I
recognize them?
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(Acetals and ketals)
When two alcohol molecules react with an
aldehyde or ketone in the presence of H, an
acetal forms. An acetal consists of a carbon
atom that is attached to two -OC
groups. (Acetals formed from ketones are also
known as ketals).
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These are acetals and ketals! How do I know?
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Exercises
Draw the organic product of each reaction.
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Exercises (More Practice make you better!)
Draw the missing reactant for each reaction.
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Drugs in the Environment
What functional groups are present on these drug
molecules?