Benzene and Phenol
- Created by: heatherbaker
- Created on: 01-03-16 20:44
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- Benzene and Phenols
- Benzene
- Kekule
- Ring Structure
- 3 C=C and 3 C-C
- 2 Forms, in equilibria, changing before reaction can occur.
- Problems
- C-C Bond Lengths
- All C-C same length
- X-Ray Diffraction
- 0.139nm
- Benzene Hydrogenation
- Benzene more stable
- Cyclohexa-1,3,5-triene: -360kJmol-1
- C-C Bond Lengths
- Ring Structure
- Delocalised Model of Benzene
- Bond angles around each Carbon: 120 (trigonal planar)
- 4 outer e- (2 bound to C 1 to H) 1 left in 2P orbital above and below plane of C atoms.
- e- in p orbital of C overlaps with other C. Ring of e- density above +below plane of C atoms.
- Overlap: pi-bonds spread over all 6C. They are delocalised.
- So, Benzene doesn't decolourise Br water, react with HCl or the halogens.
- Benzene's Reactions
- Nitration
- Benzene reacts with NO2+ conc. sulfuric acid at 50C
- (HNO3) +
- (H2SO4)
- --->
- (NO2+) +
- (HSO4-) +
- (NO2+) +
- --->
- (H2SO4)
- (H+) +
- (HSO4-)
- ---->
- (H2SO4)
- ---->
- (HSO4-)
- Halogenation
- (FeBr4-)+(H+) ----------> (FeBr3)+(HBr)
- Nitration
- Reactivity of Benzene
- Benzene
- Only decolourises Br water with halogen carrier.
- Cyclohexene
- Decolourises Br water
- Benzene
- Kekule
- Phenol
- Phenols' Reactions
- Sodium Hydroxide
- Produces C6H5O-Na+ and H20
- Partially dissociates in water- weak acid.
- Produces C6H5O- and H+
- Sodium
- 2x Produces 2C6H5O-Na+ and H2
- Sodium Hydroxide
- Ease of Bromination
- Undergoes electrophilic substitution with Br with out halogen carrier.
- More reactive than benzene due to lone pair of e-on O
- Higher e- density activates ring, polarising Br so attract more strongly than benzene.
- Uses
- Synthesis of aspirin
- Resins
- Explosives
- Antiseptics
- Phenols' Reactions
- Benzene
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