Selective intramolecular cyclization of terminal (<img src='/image/spc_char/alpha.gif' border=0>,ω)- diamines to saturated heterocyclics over modified zeolites

Abstract

The intramolecular cyclization of (<img src='/image/spc_char/alpha.gif' border=0>,ω)- diamines to heterocyclics

has been carried out over modificd zeolites. In the reaction of 2-methyl 1,5-diaminopentane over various zeolites at 300°C, the yields of 3-methylpiperidine have been found to be >95% at >95% conversion.

In the cyclization of 1,6-diaminohexane to hexamethyleneimine

over zeolites at 400°C, the yields of hexamethyleneimine are 86-95%

at >96% conversion. Similarly in the reaction of 1,4-diaminobutane

over ZSM-5 at 300°C , the yields of pyrrolidine are ~94% at >97%

conversion. The effects of various reaction parameters like reaction

temperature, weight hourly space velocity, mole ratio, time on stream,

various catalysts have been studied.

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