Synthesis of Nickel Nanoparticles Supported on Boehmite for Selective Hydrogenation of p -Nitrophenol and p -Chloronitro
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Synthesis of Nickel Nanoparticles Supported on Boehmite for Selective Hydrogenation of p-Nitrophenol and p-Chloronitrobenzene Hao Liu • Jia Deng • Wei Li
Received: 9 March 2010 / Accepted: 27 April 2010 / Published online: 14 May 2010 Ó Springer Science+Business Media, LLC 2010
Abstract Nickel nanoparticles supported on boehmite were prepared by a modified electroless nickel-plating method and a direct reduction method. We mainly studied the catalyst synthesized by the direct reduction method. The as-prepared nickel catalyst was characterized by X-ray diffraction and high-resolution transmission electron microscopy. The catalytic behavior in selective hydrogenation of p-nitrophenol to p-aminophenol and p-chloronitrobenzene to p-chloroaniline was studied and compared with Ni–B/c-Al2O3 catalyst prepared by incipient-wetness impregnation and Ni–B/Al2O3xH2O catalyst synthesized by a coprecipitation method. The Ni–B/boehmite catalysts were found to be more reactive than the Ni–B/c-Al2O3 and Ni–B/Al2O3xH2O catalysts. The superior activity of the Ni–B/boehmite catalyst was attributed to the small Ni–B particles and large amount of structural water, which enhanced the hydrophilicity of the catalyst. Keywords Ni–B Boehmite p-Nitrophenol p-Chloronitrobenzene Hydrogenation
1 Introduction Aromatic nitro-group compounds are important intermediates and fine chemicals in the chemistry of pharmaceuticals, dyes, drugs, pesticides and so on [1]. p-Aminophenol and p-chloroaniline are of great commercial importance [2–6]. The traditional synthesis routes are usually harmful
H. Liu J. Deng W. Li (&) Key Laboratory of Advanced Energy Materials Chemistry, Ministry of Education, College of Chemistry, Nankai University, Tianjin 300071, China e-mail: [email protected]
to the environment. Direct catalytic hydrogenation of aromatic nitro-group compounds could be the best choice for preparation of the corresponding aromatic amine compounds. Previously, many studies have reported that liquid phase hydrogenation is a simple way to improve the conversion and selectivity. Selective hydrogenation of aromatic nitro-group compounds to the corresponding amino-group compounds over various metal catalysts, such as Pt, Pd, Ru, Ag and Ni [7–17], has been investigated extensively. Nickel-based catalysts have been of great interest, because of applications such as hydrogenation, hydrodechlorination, and hydrotreating reactions [18]. Amorphous Ni–B catalyst has a characteristic unique structure that is ordered at short range but disordered at long range [19].This catalyst shows higher catalytic activity and selectivity than the corresponding crystalline counterparts. Aluminas are used extensively as catalyst supports in industrial hydrogenation. It is well known that the catalyst supports play an important role in the catalytic activity [20]. The catalytic performance of alumina-supported catalysts is largely dependent on the textural properties of the alumina supports [21]. Wang et al. [22] prepared colloidal RuB/ Al2O3xH2O catalyst for
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