Improvements in the synthesis of nitrogenous bases

Pyridine and 3-picoline are produced by heating one of the following mixtures in the molecular ratios indicated in the presence of an alumina-silica catalyst, the molecular ratios of the aldehydes being maintained by introducing additional aldehyde to the reaction zone to compensate for any loss due to decomposition:- It is desirable to use excess ammonia as a diluent. Methylal may be used instead of formaldehyde and the acetaldehyde may conveniently be used in the form of paraldehyde. The preferred catalyst is a natural alumina-silica such as fuller's earth having an acidic reaction. In the examples: (a) methylal and acetaldehyde are heated in the presence of activated fuller's earth to give pyridine-type bases from which pyridine is separated; (b) formaldehyde and acetaldehyde are heated in the presence of activated fuller's earth to give pyridine-type bases from which pyridine is separated; (c) formaldehyde, acetaldehyde and ammonia are heated in the presence of activated fuller's earth to give pyridine-type bases from which 3-picoline is separated.