Catalytic vapour‐phase transformation of isoquinoline to phthalimide

Abstract

Catalytic oxidation of isoquinoline yields phthalimide (major product) and smaller amounts of pyridine and hydrogen cyanide. The reaction mechanism is discussed. IntroductionDuring the carbonisation of coal, part of its nitrogen appears in the tar which contains about 2% of nitrogen heterocycles. Of these, pyridine and its derivatives constitute less than one-tenth, while quinoline, isoquinoline and its alkyl derivatives account1 for more than half. The production of large quantities of quinolines and isoquinolines is therefore inherent in any process for the recovery of pyridine and its derivatives from coal carbonisation by-products, and in view of the limited demand for the former and the short supply of the latter, possible conversion of the higher tar bases into the low-boiling picolines or the corresponding carboxylic acids seemed a profitable line of investigation.This communication reports the catalytic vapour-phase transformation of isoquinoline to phthalimide.