Advices For Studying Organic Chemistry

2. In some ways the ideal solvent for an SN2 reaction would be a nonpolar aprotic
   solvent such as a hydrocarbon or a relatively nonpolar chlorinated hydrocarbon.

1. They have low boiling points, they are inexpensive, and they are relatively
   stable.


2. Hydrocarbon or chlorinated hydrocarbon were seldom used for nucleophilic
   substitution reactions because of their inability to dissolve ionic compounds.

3. Phase-transfer catalysts are used with two immiscible phases in contact –––
   often an aqueous phase containing an ionic reactant and an organic (benzene,
   CHCl 3 , etc.) containing the organic substrate.

1. Normally the reaction of two substances in separate phases like this is inhibited
   because of the inability of the reagents to come together.


2. Adding a phase-transfer catalyst solves this problem by transferring the ionic
   reactant into the organic phase.
   i) Because the reaction medium is aprotic, an SN2 reaction occurs rapidly.

4. Phase-transfer catalysis:

Figure 11.5 Phase-transfer catalysis of the SN2 reaction between sodium cyanide
and an alkyl halide.