How to know whether a reaction is following Sn1,Sn2,Sn ar,E1,E2 or E1cb mechanism?
please mention a way which does have any exceptions.
How to know whether a reaction is following Sn1,Sn2,Sn ar,E1,E2 or E1cb mechanism?
please mention a way which does have any exceptions.
Well First look for solvent
(A) If solvent is polar protic then either reaction will go through SN1 Or E1
(B) if solvent is polar aprotic then reaction will go either through SN2 or E2
Polar aprotic solvent such as DMF, DMA, HMPA, DMSO,THF
Polar protic like water, alchol, amonia etc
Now look for temperature elimination is only favoured at high temperature because delta H and Delta S both are positive for elimination. So to make Delta G negative we have to increase the temperature.
Another thing is base E2 is favoured at strong basic medium while E1 is favoured at mild or weak basic medium.
Reactivity of alkyl halide or alchol
1 degree alkyl halide never go for SN1 or E1 it always prefer SN2 or E2. two degree may go through either SN1 or SN2 or Either E1 or E2.
So SN1 and E1 comptete each other while SN2 and E2 comptete each other.
Only elimination favourable condition is temperature.
Well First look for solvent
(A) If solvent is polar protic then either reaction will go through SN1 Or E1
(B) if solvent is polar aprotic then reaction will go either through SN2 or E2
Polar aprotic solvent such as DMF, DMA, HMPA, DMSO,THF
Polar protic like water, alchol, amonia etc
Now look for temperature elimination is only favoured at high temperature because delta H and Delta S both are positive for elimination. So to make Delta G negative we have to increase the temperature.
Another thing is base E2 is favoured at strong basic medium while E1 is favoured at mild or weak basic medium.
Reactivity of alkyl halide or alchol
1 degree alkyl halide never go for SN1 or E1 it always prefer SN2 or E2. two degree may go through either SN1 or SN2 or Either E1 or E2.
So SN1 and E1 comptete each other while SN2 and E2 comptete each other.
Only elimination favourable condition is temperature.
