Synthesis of 1,2,3,4-tetrahydrocarbazole over zeolite catalysts

1,2,3,4-tetrahydrocarbazole (CAR) has been synthesized over H-ZSM-12, H-bet a, H-mordenite, H-Y, H-ZSM-22, H-EU-1, H-ZSM-5 and acetic acid by Fisher's method using phenylhydrazine and cyclohexanone. H-Y is more active than the other zeolites studied for the synthesis of CAR. The influence of differen t parameters such as the duration of the run, catalyst concentration, react ion temperature and molar ratios of the reactants in the synthesis of CAR a re also studied. A number of arylhydrazines such as o-tolylhydrazine, p-tol ylhydrazine and 1,1-diphenylhydrazine and cyclic ketones such as cyclopenta none, cyclohexanone and 3-methylcyclohexanone have also been taken to study the effect of substitution in phenylhydrazine and the size of the cyclic k etones in the reaction. The yields of indoles correlated with the degree of substitution of the reactants and products, and the limitations imposed on diffusion through zeolite pores.