β-Molybdenum nitride: synthesis mechanism and catalytic response in the gas phase hydrogenation of p-chloronitrobenzene

Abstract

UvA-DARE is a service provided by the library of the University of Amsterdam (http://dare.uva.nl) UvA-DARE (Digital Academic Repository)β-Molybdenum nitride: synthesis mechanism and catalytic response in the gas phase hydrogenation of p-chloronitrobenzene Cárdenas-Lizana, F.; Gómez Quero, S.; Perret, N.; Kiwi-Minsker, L.; Keane, M.A. Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. A temperature programmed treatment of MoO 3 in flowing N 2 + H 2 has been employed to prepare b-phase molybdenum nitride (b-Mo 2 N) which has been used to promote, for the first time, the catalytic hydrogenation of p-chloronitrobenzene. The reduction/nitridation synthesis steps have been monitored in situ and the starting oxide, reaction intermediates and nitride product have been identified and characterized by powder X-ray diffraction (XRD), diffuse reflectance UV-Vis (DRS UV-Vis), elemental analysis, scanning electron microscopy (SEM) and BET/pore volume measurements. Our results demonstrate that MoO 3 -b-Mo 2 N is a kinetically controlled process where an initial reduction stage generates (sequentially) MoO 2 and Mo as reaction intermediates with a subsequent incorporation of N to produce b-Mo 2 N. SEM analysis has established that the transformation is non-topotactic with a disruption to the platelet morphology that characterizes MoO 3 and an increase in BET area (from 1 m 2 g À1 to 17 m 2 g À1). Moreover, temperature programmed desorption measurements have revealed a significant hydrogen uptake (0.71 mmol m À2 ) on b-Mo 2 N. This has been exploited in the hydrogenation of p-chloronitrobenzene where p-chloroaniline was generated as the sole product with an associated rate constant (k = 2.0 min À1) that is higher than values recorded for supported transition metals. Our study establishes the reaction mechanism involved in the synthesis of b-Mo 2 N and demonstrates its viability to promote selective -NO 2 group reduction as an alternative sustainable, high throughput route to commercially important haloamines.

Molybdenum Nitride Films: Crystal Structures, Synthesis, Mechanical, Electrical and Some Other Properties

“…The formation of HxMoO3 and MoO2 is observed at a temperature of 613 K during the reduction-nitridation process leading to the synthesis of molybdenum nitrides. Cardenas-Lizana et al [48] have developed a process to produce β-Mo2N from MoO3 in N2-H2 gas mixture at a temperature of 933 K and observed the reduction of MoO3 to MoO2 and Mo. In contrast with many previous studies suggesting that the formation of molybdenum nitride intermediates is a thermochemically controlled process, the authors report a kinetically controlled process.…”

Effect of Crystallographic Phase (β vs. γ) and Surface Area on Gas Phase Nitroarene Hydrogenation Over Mo2N and Au/Mo2N

“…A distinct selectivity response has been observed for Mo 2 N when compared with conventional supported metal (e.g. Pd or Pt) catalysts [5,6,8]. Indeed, the preferential formation of crotyl alcohol (from crotonaldehyde) [6] and ethene (from ethyne) [5] has been reported for reaction over Mo 2 N with enhanced selectivities relative to Pd/Al 2 O 3 .…”

“…The application of transition metal nitrides as hydrotreating catalysts is now established [1][2][3]. The use of molybdenum nitride (Mo 2 N) to promote hydrogen mediated reactions has been considered to a limited extent with evidence of significant hydrogenation activity [4][5][6][7][8][9]. This has been ascribed to a contraction of the d-band and modification of electron density due to the interstitial incorporation of N in the metal lattice, which facilitates hydrogen adsorption/ activation [10].…”

Preparation and Catalytic Performance of Metal-Rich Pd Phosphides for the Solvent-Free Selective Hydrogenation of Chloronitrobenzene

“…Metal nitrides have also been considered great potential catalysts owing to their similarity with Group VIII metals. Recently, the temperature-programmed treatment of MoO 3 in flowing N 2 + H 2 has been employed to prepare β-phase molybdenum nitride (β-Mo 2 N), which promotes the continuous gas phase hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroanilines (p-CAN) with 100% selectivity in terms of -NO 2 group reduction [16]. The ternary Pt-Mo 2 N/SBA-15 catalysts have shown superior performance for the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol [28].…”

“…However, the highly selective synthesis of aromatic haloamines remains an unsolved challenge on almost all kinds of metal catalysts, such as Pt, Pd, Ni, Ru, and Au [7,8]. Numerous research efforts have been devoted to the suppression of the hydrodehalogenation side reaction, such as modulating metal particle size [9], adding organic additives [10][11][12][13], synthesizing metal complexes [14][15][16], adding metal promoters [7,17,18], and modifying the interaction between metal active components and metallic oxide supports [19]. Recently, co-based catalysts as representatives of non-noble metals have been proposed, and the catalytic performance of the hydrogenation of halonitrobenzenes has been explored [20].…”