Question

m-toluic acid is first reacted with thionyl chloride in the presence of catalytic pyridine to prepare m-toluoyl chloride, which is then immediately reacted with diethylamine to produce the desired amide, N,N-diethylm-toluamide.

a) What is the driving force for the reaction between the carboxylic acid and thionyl chloride to form the acid chloride?

b) Why is pyridine added to the reaction mixture? Explain the role of the pyridine with respect to the reaction mechanism and expected reaction intermediates.

c) What is the identity of the “white smoke” produced when the ethereal solution of diethylamine is added to the acyl chloride? Support your answer by writing a balanced reaction.

e) What impurities may be present in the DEET that you prepared? List the expected appearance of the signals due to these impurites in the 1 H NMR spectrum of the product.

f) A student dissolved the diethylamine in reagent-grade diethyl ether instead of anhydrous diethyl ether. How would this change affect the reaction outcome?

Answer 1