Nucleophilic Substitution Reactions

The nucleophilic substitution reactions on substrates that have optical activity (the ability to rotate plane-polarized light) shows that two general mechanisms exist for these types of reactions.

-        The first type is called an SN1 reaction which follows first order kinetics that the reaction rate more likely depends on the concentration of one compound. Therefore, this is called unimolecular.

-        The second type of nucleophilic substititution reaction is SN2 (Substitution nucleophilic bimolecular) and has secon order kinetics; the reaction rate depends on the concentartions of two molecules.