Cargando…

Catalytic Hydrogenation of p-Chloronitrobenzene to p-Chloroaniline Mediated by γ-Mo(2)N

[Image: see text] Promoting the production of industrially important aromatic chloroamines over transition-metal nitrides catalysts has emerged as a prominent theme in catalysis. This contribution provides an insight into the reduction mechanism of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-...

Descripción completa

Detalles Bibliográficos
Autores principales: Jaf, Zainab N., Altarawneh, Mohammednoor, Miran, Hussein A., Almatarneh, Mansour H., Jiang, Zhong-Tao, Dlugogorski, Bogdan. Z.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2018
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6644804/
https://www.ncbi.nlm.nih.gov/pubmed/31458126
http://dx.doi.org/10.1021/acsomega.8b01936
Descripción
Sumario:[Image: see text] Promoting the production of industrially important aromatic chloroamines over transition-metal nitrides catalysts has emerged as a prominent theme in catalysis. This contribution provides an insight into the reduction mechanism of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN) over the γ-Mo(2)N(111) surface by means of density functional theory calculations. The adsorption energies of various molecularly adsorbed modes of p-CNB were computed. Our findings display that, p-CNB prefers to be adsorbed over two distinct adsorption sites, namely, Mo-hollow face-centered cubic (fcc) and N-hollow hexagonal close-packed (hcp) sites with adsorption energies of −32.1 and −38.5 kcal/mol, respectively. We establish that the activation of nitro group proceeds through direct pathway along with formation of several reaction intermediates. Most of these intermediaries reside in a significant well-depth in reference to the entrance channel. Central to the constructed mechanism is H-transfer steps from fcc and hcp hollow sites to the NO/–NH groups through modest reaction barriers. Our computed rate constant for the conversion of p-CNB correlates very well with the experimental finding (0.018 versus 0.033 s(–1) at ∼500 K). Plotted species profiles via a simplified kinetics model confirms the experimentally reported high selectivity toward the formation of p-CAN at relatively low temperatures. It is hoped that thermokinetics parameters and mechanistic pathways provided herein will afford a molecular level understanding for γ-Mo(2)N-mediated conversion of halogenated nitrobenzenes into their corresponding nitroanilines; a process that entails significant industrial applications.