The purpose of the experiment was to examine the reactivity’s of several different substrates under SN2 reaction conditions.
Discussion: All of the SN2 reaction mechanisms react the exact same way. The nucleophile sodium iodide attacks the delta positive alpha carbon forming an intermediate that has a partially formed C-I bond and a partially broken bond between carbon and the delta negative leaving group. The stereochemistry is inverted at the alpha carbon as the C-I bond fully forms. Then the leaving group comes off of the molecule taking the electrons it shared with the alpha carbon. The reason that only 1-chlorobutane and 1-bromobutane formed a precipitate is because the carbon that bears the leaving group is primary. An SN2 reaction mechanism works the best (and fastest) with primary substrates due to less steric hindrance being …show more content…
In this reaction, acetone was used because it is a polar aprotic solvent, meaning that it has no –OH or –NH groups. Polar aprotic solvents increase the SN2 reaction rate by surrounding the accompanying cation and therefore, raising the ground-state energy of the nucleophile. The reason that 2-chlorobutane and 2-bromobutane did not form a precipitate is because the carbon that bears the leaving group is a secondary substituent. Also, the tertiary t-butyl chloride did not form a precipitate for the same reason that the secondary substituents did not form a precipitate. The reason being that, t-butyl chloride is so sterically hindered that the carbon is barely visible to the nucleophile making it difficult to attack. Steric hindrance is an issue because SN2 reactions attack from the opposite side of the molecule creating an inversion of stereochemistry. Therefore, the carbon is buried under different atoms making it difficult for the nucleophile to find the carbon. SN2 reactions are called concerted reactions because they occur in one step and do not
Discussion: All of the SN2 reaction mechanisms react the exact same way. The nucleophile sodium iodide attacks the delta positive alpha carbon forming an intermediate that has a partially formed C-I bond and a partially broken bond between carbon and the delta negative leaving group. The stereochemistry is inverted at the alpha carbon as the C-I bond fully forms. Then the leaving group comes off of the molecule taking the electrons it shared with the alpha carbon. The reason that only 1-chlorobutane and 1-bromobutane formed a precipitate is because the carbon that bears the leaving group is primary. An SN2 reaction mechanism works the best (and fastest) with primary substrates due to less steric hindrance being …show more content…
In this reaction, acetone was used because it is a polar aprotic solvent, meaning that it has no –OH or –NH groups. Polar aprotic solvents increase the SN2 reaction rate by surrounding the accompanying cation and therefore, raising the ground-state energy of the nucleophile. The reason that 2-chlorobutane and 2-bromobutane did not form a precipitate is because the carbon that bears the leaving group is a secondary substituent. Also, the tertiary t-butyl chloride did not form a precipitate for the same reason that the secondary substituents did not form a precipitate. The reason being that, t-butyl chloride is so sterically hindered that the carbon is barely visible to the nucleophile making it difficult to attack. Steric hindrance is an issue because SN2 reactions attack from the opposite side of the molecule creating an inversion of stereochemistry. Therefore, the carbon is buried under different atoms making it difficult for the nucleophile to find the carbon. SN2 reactions are called concerted reactions because they occur in one step and do not