No abstract

No abstract

No abstract

Continuous flow pyrolysis (CFP) and annulation reactions of pyrrole (1), its benzo-annulated derivatives indole (2) and carbazole (3), pyridine (4), quinoline (5), and isoquinoline (6) have been investigated at 900 o C. While for 1, 2, 4-6 between 15 and 24 products were identified by GC-MS, 3 is rather stable under the reaction conditions and naphthalene (18) was found as the only substantial product. Except for 3, about 10 compounds were always present in the pyrolysate, benzonitrile (14) (6-24%) and naphthalene (18) (2-21%) being the most prominent products. Compounds 4-6 have even 16 common pyrolysis products. Among the major products are nitrogen heterocycles like quinoline (5) (4-13%), isoquinoline (6) (0-8%), and indole (2) (0.5-3%), cyano-substituted aromatic hydrocarbons like 14, 1-cyanonaphthalene (17) (0-16%), and 9-cycanoanthracene (19) (0-6%), as well as the corresponding unsubstituted parent compounds like 18, phenanthrene (31) (2-10%), pyrene (38) (1-5%), and fluoranthene (22) (2-8%). In addition to the volatile products, several heavy compounds were identified by direct inlet MS. Possible routes of product formation are outlined. The relative amounts of unreacted starting material clearly indicate that benzo-annulation of pyrrole and pyridine causes considerable increase of thermal stability.