SN1 Reaction :
1)First order kinetics
2)Two or more steps with a reactive intermediate.
3)Sensitive to electronic effects.
4)side products possible due to rearrangement.
5)Competes with E1.
6)Substrate preferences 30>20>10>Me
7)Typically 30 halides are the best.
8)requies polar protic solvents.
9)Usually the solvent is the nucleuphile.
SN2 :
1)Second order kinetics.
2)single elementary steps , no reactive intermediate ; a
single transition state.
3)No rearrangement possible.
4)Competes with E2.
5)Substrate preferences : Me>10>20>30
6)Typically 10 halides are the best.
7)Much better in aprotic solvents (eg : DMF ).
8)Strong nucleuphile in high concentration favour it.
E1 :
1)Two step , cation intermediate.
2)Competes with SN1.
3)Favoured in 30 substrates.
4)favoured by polar protic solvents.
5)Base strength is irrelevant.
E2 :
1)Single step , no intermediate.
2)Competes with SN2.
3)Trans co-planar , Trans-diaxial.
4)Suspectible to steric effects.
5)Favoured in less polar solvent.
6)Favoured by strong and hindred bases.
7)Favoured by increased Temperature.
Hope all of you find it useful.
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