Quaternary ammonium salts catalyze reactions between species dissolved in two immiscible phases, a phenomenon called phase-transfer catalysis. For example, heating a mixture of 1-chlorooctane dissolved in decane with aqueous sodium cyanide shows no sign of the SN2 product, nonanenitrile. On the other hand, addition of a small amount of (phenylmethyl)triethylammonium chloride results in a rapid, quantitative reaction. 

As a team, discuss possible answers to the following questions: 

(a) What is the solubility of the catalyst in the two solvents? 

(b) Why is the S_N2 reaction so slow without catalyst? 

(c) How does the ammonium salt facilitate the reaction?

Transcribed Image Text:

C CH3(CH2),CI + Na* CN → CH;(CH,),CN + Na*Cl- 100% (Phenylmethyl)- triethylammonium 1-Chlorooctane Nonanenitrile chloride