Nucleophilic Substition ReactionsPaper Rating: Word Count: 3558 Approx Pages: 14
Nucleophilic Substitution Reactions:
The purpose of this lab is to compare the nucleophilic abilities of the addition of chloride and bromide ions to the compounds of n-butyl alcohol and tertiary butyl alcohol, in SN1 and SN2 environments. This will determine which of the anions is the better nucleophile, in each mechanism.
To better understand the reactivity of competing nucleophiles, the mechanisms of their reactions must be observed. In the lab, both of the basic nucleophilic mechanisms of unimolecular and bimolecular substitution reactions take place. In both of these reactions, the reactivity is based on the substrates structure, the nucleophile's basicity, and the reaction conditions, such as the solvent used and the temperature (Smith 389). In the substitution bimolecular reaction (SN2), the reaction is bimolecular and takes place in a one-step process. The rate is dependent on both the concentration of the substrate and the nucleophile. This makes the mechanism a second-order reaction. The rate law is described as Rate = k [substrate][nucleophile] (Carey 331). If a large excess of the nucleophile is present then the law would be a pseudo-first order reaction (false-first order) (Smith 390