Spectroscopic witness from reactants to product: FTIR studies on selective mono- N-methylation of aniline on Cu 1− xZn xFe 2O 4

Abstract

An active N-methylation ferrospinel catalyst, Cu 1− x Zn x Fe 2O 4, is reported for the first time. A mechanistic approach to selective mono- N-methylation of aniline on Cu 1− x Zn x Fe 2O 4 is successfully explained by in situ temperature-dependent DRIFTS studies of reactants on the catalyst. Perpendicular orientation of aromatic rings of aniline, methyl group availability, an optimum metal–ion distribution on the catalyst surface, and a stable methyl group on Zn leads selectively to N-methylaniline (NMA) on Cu 0.5Zn 0.5Fe 2O 4. Desorption-limited kinetics is evident from NMA formation at low temperatures.