Catalytic formation of pyridine bases from crotonaldehyde and ammonia

Thermodynamic and kinetic data are presented for the formation of pyridine bases by reaction between crotonaldehyde and ammonia in the vapor phase at atmospheric pressure. It is shown that low yields of pyridines are obtained because thermal cracking of crotonaldehyde occurs preferentially. Results obtained with acidic and basic catalysts are reported. The presence of water vapor is shown to favor the formation of 5-ethyl-2-picoline. Routes to the various pyridines are discussed in the light of available evidence.