Halogenoalkanes Revision Notes

Halogenoalkanes
General formula = C
nH2n+1X


X is a halogen, it's slightly ­ve.
Halogenoalkanes are polar.
The curly arrow shows the movement of the free pair of electrons.

Nucleophile ­ electron donor pair
It replaces X.

:OH = Hydroxide ion and it makes an alcohol
:NH3 = Ammonia and it…

Elimination Reaction ­
Potassium Hydroxide (alcoholic) + Halogenoalkane Alkane + H2O


KOH acts as a base.
Tertiary halogenoalkanes tend towards elimination.






Ozone Depletion ­
Ozone formed naturally in upper atmosphere, beneficial because absorb UV
radiation.
Cl atoms formed in upper atmosphere when UV causes CCl bonds to break in
CFCs.…

Overall Equations ­
Cl· + O3
ClO· + O2 and ClO· + O
3
O3 + 2O
2 +Cl·



CH4 + Cl
2
CH3Cl + HCl


Free radical substitution happens in three stages:
1) Initiation
2) Propagation
3) Termination