Selective intramolecular cyclization of terminal (alpha,omega)- diamines to saturated heterocyclics over modified zeolites

The intramolecular cyclization of (alpha, omega)- diamines to heterocyclics has been carried out over modified zeolites. In the reaction of 2-methyl 1 ,5-diaminopentane over various zeolites at 300 degrees C, the yields of 3-m elhylpiperidine have been found to be >95% at >95% conversion. In the cycli zation of 1,6-diaminohexane to hexamethyleneimine over zeolites at 400 degr ees C, the yields of hexamethyleneimine are 86-95% at >96% conversion. Simi larly in the reaction of 1,4-diaminobutane over ZSM-5 at 300 degrees C, the yields of pyrrolidine are similar to 94% at >97% conversion. The effects o f various reaction parameters like reaction temperature, weight hourly spac e velocity, mole ratio, time on stream, various catalysts have been studied .