The main source of pyridine is coal tar, In view of the small percentage of pyridine in this source, Ol%, l* it was thought desirable to investigate various synthetic methods. The catalytic syntheses of pyridine have been extensively reported in both scientific and patent literature.* Nearly all of these processes fall into three classes:(a) the reaction of unsaturated hydrocarbons such as ethylene and acetylene with ammonia or hydrogen cyanide,(b) the ...