Nucleophilic Substitution Lab Report

Nucleophilic substitutions are a fundamental class of reactions in organic chemistry. This type of reaction involves a nucleophile, or an electron rich species, attacking an electrophilic site, or an area that carries a positive or partially positive charge, in order to replace a leaving group. There are two possible mechanisms to account for the attack of the nucleophile; the first occurs in a concerted process, or in one step and the second mechanism occurs in two steps and involves a carbocation intermediate. As the nucleophile is attacking in the concerted process, the leaving group is leaving, thus the atom does not break the octet rule. This type of reaction, known as an SN2 reaction, has a rate that is dependent on both the concentration of the substrate in addition to the concentration of the nucleophile. Given that the nucleophile must attack while the leaving group is still attached, steric hindrance plays a large role in determining if the reaction will occur. This leads to a primary or methyl substrate being favored for SN2 reactions.
On the other hand, a nucleophilic substitution reaction can also occur in a stepwise matter, known as an SN1 mechanism. First, a loss of the leaving group would occur, forming a carbocation intermediate, which is then attacked by the nucleophile. Given that this reaction forms the carbocation intermediate, steric hindrance is not a factor so this mechanism is preferable on a tertiary substrate. However, the rate of this reaction is dependent on the rate at which the …show more content…
RX + NaI RI + NaX (X= Cl or Br)
2. RX + AgNO3 + EtOH ROEt + AgX + HNO3
General alcohol equation:
ROH + HCl RCL + H2O

Example Mechanisms
2-bromobutane in NaI/acetone:

2-bromobutane in AgNO3/ethanol:

2-methyl-2-propanol in HCl-ZnCl2