Does the solvent play a role in determining which pathway the reaction will take, SN1 versus SN2? How?

Question

Lucy Alessi · Accepted Answer

It affects more their reaction rates.

The solvents plays a minimal role in determining the mechanism as #S_(N1) or S_(N2)#.

#S_(N1)# mechanism favours polar protic solvents however, #S_(N2)# mechanism favours polar aprotic solvents.

Polar protic solvents can hydrogen bond (or form a strong intermolecular ion-dipole interaction) with the nucleophile and therefore, weakening its nucleophilicity, however, polar aprotic solvents do not interact with the nucleophile.

This is because, #S_(N1)# mechanism favours weak nucleophile and #S_(N2)# mechanism favours strong nucleophile.

Here is a video that explains in details how to predict the mechanism as #S_(N1) or S_(N2)#.

Jacob Anderson · Answer

undefined Yes, the solvent can play a role in determining whether a reaction follows an SN1 or SN2 pathway. Polar protic solvents tend to favor SN1 reactions, while polar aprotic solvents tend to favor SN2 reactions. This is because the nature of the solvent can affect the stability of the carbocation intermediate in SN1 reactions and the nucleophile in SN2 reactions.