4.2 (alcohols, haloalkanes, analysis)

1. Primary Haloalkane
   1. Halogen at the end
2. Reactivity
   1. Atoms get bigger down the group
      1. Strong sheilding
      2. Lower mean bond enthalpies
         1. So more reactive down the group
   2. Electronegativity decreases down the group
      1. C-H bonds are polar
         1. Highest polarity more likely to react
            1. Polarity decreases down
3. Nucleophilic Substitution
   1. Atom/ group of atoms exchanged for a nucleophile
      1. Nucleophile
         1. electron-pair donor
         2. Attracted to δ+ C
   2. Hydrolysis
      1. Reacting species = H₂O or -OH ion
      2. Rate
         1. Bond enthalpy is the most important
         2. Least polar = Fastest rate
         3. Faster with aq alkali
      3. C-X bond undergoes heterolytic fission to produce halide ion
         1. Halide ions form a coloured precipitate when acidic silver nitrate is added
4. Environment
   1. CFCs
      1. Don't react
      2. Non-toxic
      3. Fridges, making plastic, fire-extinguishers
      4. Become exposed to UV
         1. Homolytic fission creates Cl radicals
            1. These catalyse the decomposition of O₃ to O₂
   2. Ozone layer protects from UV-B/C radiation
      1. Problematic hole in O₃ layer

1. Quickfit apparatus
   1. Grease joints slightly
   2. Water at the bottom of condnser
2. Purifying an organic liquid
   1. Redistillation
      1. Distillate is distilled to make really pure
   2. Separating funnel
      1. Organic layer is less dense than water
         1. So can be romoved
      2. Pour liquid through funnel. Swirl vessel with water and add to funnel
         1. Equalise pressure
            1. remove water and collect organic layer
   3. Drying agents
      1. Inorganic salts remove water
         1. Use gravity filtration to collect the organic product
3. Functional group tests
   1. Unsaturated Hydrocarbon
      1. Bromine water decolourises
   2. Haloalkane
      1. AgNO₃, C₂H₆O, H₂O
         1. White precip = Chloro
         2. Cream precip = Bromo
         3. Yellow precip = Iodo
   3. Carbonyl
      1. Acidified K ₂Cr₂O₇
         1. Ketones = no
         2. Aldehyde = Orange - Green
      2. Fehling's
         1. aldehyde = dark red precip
      3. Tollens'
         1. Ketones = no silver mirror
   4. Carboxylic acid
      1. Universal indicator
         1. Weak acid pH
      2. Reactive metal/ metal carbonate
         1. effervescence
            1. Hydrogen
            2. CO₂
   5. Alcohol
      1. Carboxylic acid, H₂SO₄
         1. Smell of ester
4. Spectroscopy
   1. Mass Spectroscopy
   2. Infrared Spectroscopy

Anlagen:

• Alcohols

1. Properties of alcohols
   1. Structure
      1. Primary
      2. Secondary
      3. Tertiary
   2. Boiling Point
      1. Increases as chain length increases
      2. More SA contact
      3. Stronger London forces
      4. Strong hydrogen bonds
   3. Evaporation
      1. Volatility increases as boiling point decreases
   4. Solubility
      1. Polar -OH
      2. Chain length increases Solubility decrease
2. Reactions of Alcohols
   1. Oxidation
      1. Primary
         1. Aldehyde
         2. Carboxylic acid
      2. Secondary
         1. Ketone
      3. Tertiary
         1. No Reaction
   2. Esterification
      1. -COOR
      2. Esters used in foods and as solvents
      3. React carboxylic acid with an alcohol
      4. Concentrated H₂SO₄ and 80'C hot water bath speed reaction
         1. Continually distilled
      5. Mainly insoluble in water
         1. Visible oily layer
   3. Dehydration
      1. Elimination of H₂O
      2. Strong acid, 170'C, Ruflux
      3. π-bond forms
   4. Halide Substitution
      1. ROH+HX-->RX+H₂O
      2. Acid catalyst H₂SO₄, mixture warmed
         1. H₃PO₄ used for iodide