Hydrogenation of p‐Chloronitrobenzene over Nanostructured‐Carbon‐Supported Ruthenium Catalysts

Abstract

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) have been used for the first time to support ruthenium nanoparticles for the hydrogenation of p-chloronitrobenzene (p-CNB) to produce selectively p-chloroaniline. The preparation of well-dispersed ruthenium catalysts from the [Ru(3)(CO)(12)] precursor required activation of the purified supports by nitric acid oxidation. The supports, purified and functionalized, and the supported catalysts have been characterized by a range of techniques. The catalytic activity of these materials for the hydrogenation of p-CNB at 35 bar and 60 °C is shown to reach as high as 18 mol(p-CNB)g(Ru)(-1) h(-1), which is one order of magnitude higher than a commercial Ru/Al(2)O(3) catalyst. Selectivities between 92 and 94 % are systematically obtained, the major byproduct being aniline.

Effect of the Carbon Support on the Catalytic Activity of Ruthenium‐Magnetite Catalysts for p‐Chloronitrobenzene Hydrogenation

“…[21] In this case, the observedv ariations can be accounted for by assuming that the catalytic activity is highero nt he dense planes of the Ru particles; indeed,s uch ap henomenonhas already been reported for the hydrogenation of p-CNB over Ru/Al 2 O 3 catalysts. [22] Besides the particle size effect, particle proximity and spatiald istribution have been identified recently as crucial parameters that may influence catalyst activity [23] and stability.…”

Heterogeneous Catalysis on Nanostructured Carbon Material Supported Catalysts

“…130 CNTs, γ-Al 2 O 3 and SiO 2 supported Pt and Pd catalysts were produced by laser vaporization deposition of respective bulk metals, and tested for selective hydrogenation of p-chloronitrobenzene. 131 The results show that the catalytic properties are greatly affected by the supports.…”

Noncovalently functionalized carbon nanotubes immobilized Fe–Bi bimetallic oxides as a heterogeneous nanocatalyst for reduction of nitroaromatics

“…Numerous CNTs-related catalysts have been prepared over the past decades because of the CNTs' excellent properties, such as special electronic and optoelectronic conduction, and physical and chemical stabilities [36,37]. Particularly, various stable metal-CNTs nanocomposites have been successfully fabricated, such as metallic Ni [38], Pt [39], Pd [40] and Ru-CNT [41], which demonstrates that the CNTs is a kind of wonderful supporters for metal nanoparticles [42]. However, the hydrophobicity and self-coalesce of the CNTs sometimes restrict their application.…”