Organics: Continued from Level 2'

1
Organics Continued from Level 2.

• Alcohols
• Haloalkanes

2
Alcohols - Oxidation

• Back in Level 2 organic chemistry we learnt that
  alcohols come in three main forms
• Primary
• Secondary
• Tertiary
• We also found out that primary alcohols can be
  oxidised to form carboxylic acids
• Later we will discover that primary alcohols can
  be partially oxidised to form a group called
  aldehydes. Then the aldehydes can be oxidised
  further to form carboxylic acids
• This year we will also discover that secondary
  alcohols can be oxidised to form ketones

3
Alcohols - Substitution

• This year we are introduced to a new set of
  chemicals that add chlorine to organic chemicals.
  Two of these are
• PCl5 phosphorus pentachloride
• SOCl2 thionyl chloride
• These can be used to substitute the OH group in
  an alcohol with a Cl
• CH3OH PCl5 CH3Cl POCl3 HCl
• CH3OH SOCl2 CH3Cl SO2 HCl

4
Haloalkanes

• Last year we also discovered a few things about
  haloalkanes, like the facts that
• They are made by halogenating unsaturated
  hydrocarbons
• We can also use hydrogen halides to create halo
  alkanes from unsaturated hydrocarbons
• When hydrohalogenation occurs, we must work out
  where the H and the halogen get placed. To do
  this we follow Markovnikovs rule (Birds of a
  feather flock together in this case, the
  hydrogen will flock closest to the most
  hydrogens that it can)

Minor product
Major product
5
Haloalkanes Substitution

• Some chemicals have the ability to remove the
  halogens from a haloalkane. These chemicals have
  a strong attraction to positive nuclei, we
  therefore call them nucleophiles (nucleus friend)
• Three good nucleophilic substituters are
• Hydroxide
• Water
• Ammonia (dissolved in alcohol not water)

6
Haloalkanes - Elimination

• The halogen can also be removed (eliminated) from
  the haloalkane leaving an alkene behind
• The reagent used in this process is KOH or NaOH
  dissolved in alcohol (just like the NH3 in the
  substitution section)
• We have a similar rule (to the Markovnikov rule)
  to follow so that we can determine where the
  double bond goes The hydrogens still like to
  flock together in the largest amount possible

Major product
Minor product