Organic Chemistry

• Alkane -> Haloalkane


  Substitution

  Br2 or Cl2 w/ UV light, is a slow reaction
• Haloalkane -> Alcohol


  Substitution

  KOH (aq)
• Alcohol -> Haloalkane


  Substitution

  SOcl2 or PCl3 or PCl5 or (conc.) HCl/HBr
• Haloalkane -> Amine


  Substitution

  (conc.) or (alc.) NH3
• Alkene -> Di-haloalkane


  Br2/Cl2 (very fast reactions)
• Alkene -> Alkane


  Addition

  H2 with Ni/Pt and heat
• Alkene -> Haloalkane


  Addition

  HCl or Hbr
• Alkene -> Alcohol


  Addition

  H2O/ H+ (water in acid conditions)
• Addition reactions


  Reactions that involve the addition of new atoms to unsaturated carbon compounds
• Substitution reactions


  Reactions that involve the substitution of hydrogen atoms of saturated carbon compounds with other atoms or groups of atoms
• Haloalkane -> Alkene


  Elimination

  KOH (alc) + heat
• Alcohol -> Alkene


  Elimination

  (conc.) H2SO4 + heat
• Saytzeff's rule


  The adjacent C-atom (to the functional group) that is bonded to the least H-atoms, is more likely to lose the H-atom
• Markovnikov's rule


  The C-atom of the double bond that has the most H-atoms attached is most likely to gain the hydrogen
• Structural isomers must have...

  The same number + type of atom (same molecular formula)

  But different arrangement of atoms
• Functional group priority list:

  • Carboxylic acid
  • Alcohols
  • Amines
  • Halo-functional groups
• For a molecule to have geometric isomers ....

  • A double bond (that restricts rotation)
  • Each C-atom in double bond must have 2 different atoms/groups bonded to it
• Saytzeff's rule


  The adjacent C atom (to the functional group) that is bonded to the least H atoms, will preferentially lose another H in an elimination reaction to produce the major product

  
• Elimination reaction


  A functional group and an H from adjacent carbon atoms are removed, and a C=C double bond is formed in the organic product
• Oxidation of alkenes


  1. Alkenes can be oxidised to di-alcohols using neutral potassium permanganate – MnO4-

  2. Observation: purple solution ⇢ brown solid (MnO4- ⇢ MnO2)
• Oxidation of 1o alcohols

  1. 1o alcohols can be oxidised to carboxylic acids using acidified potassium permanganate – MnO4- / H+

  2. Observation: purple solution ⇢ colourless solution (MnO4- ⇢ Mn+)

  3. 1o alcohols can also be oxidised using acidified potassium dichromate – Cr2O72- / H+

  4. Observation: orange solution ⇢ green solution (Cr2O72- ⇢ Cr3+)
• Observations

  MnO4- (neutral): purple solution ⇢ brown solid

  MnO4- / H+: purple solution ⇢ colourless solution

  Cr2O72- / H+: orange solution ⇢ green solution
• Alkanes

  1. Br2 / UV light

  2. Alkane → haloalkane

  3. Substitution

  4. There is a SLOW colour change from orange-brown to colourless as Br2 is used up in the reaction
• Alkenes (and Alkynes)

  1. Br2

  2. Alkene → di-haloalkane

  3. Addition

  4. There is a FAST colour change from orange-brown to colourless as Br2 is used up in the reaction

  5. MnO4- (neutral)

  6. Alkene → di-alcohol

  7. Oxidation

  8. There is a change from a purple solution to a brown-black solid (MnO4- → MnO2)
• Alkanes, alkenes, alkynes and haloalkanes are INSOLUBLE when added to water. Two layers will be observed
• Alcohols, amines and carboxylic acids are SOLUBLE when added to water. A single solution will be observed
• In an elimination reaction, a functional group and an H-atom from an adjacent C-atom are removed, creating a double c=c bond
• Oxidation of primary alcohols using H+/MnO4 OR Cr2O7

  The purple MnO4- is reduced to colourless Mn2+

  The Cr2O72- is reduced to blue/green Cr3+
• An acid produces H3O+ in solution
• A base produces OH- in solution
• Acid + Base = Salt + water
• Acid + (reactive) metal = Salt + Hydrogen
• Acid + Carbonate/Hydrogen Carbonate = Salt + water + Carbon dioxide
• A polymer is a very long molecule made up of small molecules (called monomers) that are repeatedly joined together
• Polymers have high melting points because they contain many strong covalent bonds between the atoms in their chains.
• Addition polymers are called addition polymers because the c=c double bond breaks and now single bonds form to join the monomers together
• Double bonds between c=c are very reactive, while single c-c bonds are less reactive, so addition polymers are less reactive than the alkene monomers
• Addition polymerisation occurs when alkenes react with each other to form a long chain polymer. In addition polymerisation, the reactive c=c double bond is broken, and the electrons that formed the double bonds are used to join neighbouring monomers together, creating single c-c bonds between them.
• Polymer


  A very long molecule made up of small molecules (called monomers) that are repeatedly joined together