A mechanism for the carboxylic acid-nitrile exchange reaction

The designer of a reaction mechanism must follow certain rules. Gathering enough information to present a mechanism which will stand close scrutiny is hard enough, but to fit the facts gathered to a consistent theory is, at times, very difficult. Not only must a mechanism account for the products of the reaction, and any side products, it must also be able to predict the relative rates of reaction for a series of reactants. Any basic theories which help the investigator rationalize the mechanism are valid. This study is on the carboxylic acid-nitrile exchange reaction. In the most simple terms, the reaction involves the exchange of the carboxylic acid function of one compound for the nit rile function of another compound, as in equation (1). R-COOH + R’-CN ==== R-CN + R'-COOH (l)