Starter

1
Starter

• 1)Write an equation for the reaction between
  methanol and butanoic acid. Name the organic
  product formed.
• 2) Name the following compounds
• CH3CH2CH2CHClCH3
• CH3CH2CHBrCHClCH

2
Halogenoalkanes

• L.O.
• Describe the structure, general formula and uses
  of halogenoalkanes.
• Describe and explain the nature of the
  carbonhalogen bond and its susceptibility to
  nucleophilic attack.
• Define the term nucleophile as an electron pair
  donor

3

• In pairs
• Explain which is the most electronegative atom.
• Explain the trend of electronegativity in group
  7.
• Explain why the C-Cl bond is polar.
• Which of these bonds is more polar C-F, C-Cl,
  C-Br, C-I.

4

• Polarity of the carbon-halogen bond

5

• Polarity of the carbon-halogen bond decreases
  down the group

6

• Reactions of haloalkanes
• L.O.
• Describe the hydrolysis of halogenoalkanes as a
  nucleophilic substitution reaction.
• Describe the mechanism of nucleophilic
  substitution in the hydrolysis of primary
  halogenoalkanes with hot aqueous alkali.
• Explain the rates of primary halogenoalkane
  hydrolysis in terms of the relative bond
  enthalpies of carbonhalogen bonds.

7

• In pairs
• 1) What is a nucleophile?
• 2) Examples of nucleophiles.

8

• Mechanism for nucleophilic substitution

9

• Curly arrows are used to represent the movement
  of electron pairs

10

• In pairs
• Predict the relative rate of hydrolysis of
• R-Cl, R-Br and R-I

11
Bond Bond enthalpy (KJ mol-1)
C-F 467
C-Cl 340
C-Br 280
C-I 240
12

• Rates of hydrolysis of halogenoalkanes

In hydrolysis of halogenoalkanes, the bond
enthalpy is more important that bond polarity.
13

• Reactions of haloalkanes
• L.O.
• Describe the hydrolysis of halogenoalkanes as a
  nucleophilic substitution reaction.
• Describe the mechanism of nucleophilic
  substitution in the hydrolysis of primary
  halogenoalkanes with hot aqueous alkali.
• Explain the rates of primary halogenoalkane
  hydrolysis in terms of the relative bond
  enthalpies of carbonhalogen bonds.