One-pot synthesis of N-methylpyrrolidine (NMPD) using Cu- and Ni-modified ZSM-5 as an efficient catalyst

Abstract

In this study, a green, efficient and low-cost process for the synthesis of N-methylpyrrolidine (NMPD) from 1,4-butanediol (BDO) and methylamine (MA) via a one-pot method was developed. Under the optimized reaction conditions, more than 90% yield of NMPD was achieved over a Cu and Ni modified ZSM-5 catalyst. The catalyst could be reused for several runs retaining a satisfactory catalytic performance, and the scale-up operation showed the potential of industrial application. Characterizations of BET, XPS, XRD, TEM, SEM, H₂-TPR and NH₃-TPD were conducted for the developed composite catalyst, which suggested that Cu₂O and NiO were the main species on the support. Meanwhile, it was found that the H₂ atmosphere, the high dispersion of metal oxides and the synergic effect between Cu and Ni species on ZSM-5 contributed to the excellent catalytic performance. Furthermore, a possible mechanism based on a borrowing-hydrogen process was also proposed.