Effect of Organic Nickel Precursor on the Reduction Performance and Hydrogenation Activity of Ni/Al2O3 Catalysts

Abstract

Different nickel precursors, i.e., nickel nitrate, nickel acetate and nickel acetate plus citric acid, were used to prepare supported Ni/gamma-Al2O3 catalysts for naphthalene hydrogenation to decalin. The catalysts thus prepared were reduced without calcination and after calcination, respectively. The physicochemical characterization and activity testing results show that the catalyst prepared with nickel acetate as precursor and reduced without calcination possesses modest reduction character, higher adsorption and desorption abilities of H-2, and exhibits most excellent catalytic performance for the reaction with 99.1% selectivity of decalin at the naphthalene conversion of 100%.Ministry of Science and Technology of China [2004CB217805

A High (Z)/(E) Ratio Obtained During the 3-Hexyne Hydrogenation with a Catalyst Based on a Rh(I) Complex Anchored on a Carbonaceous Support

“…E isomerization, and n-hexane (not plotted in Fig. 1 because of the low values obtained and for the sake of clarity) produced either by hydrogenation of the alkyne or the alkene isomers [7,37]. Last but not least, [RhCl(NH 2 (CH 2 ) 12 CH 3 ) 3 ]/RX3 showed the lowest conversion values to the (E) isomer and to the alkane.…”

“…: by varying (a) the active species or (b) the support, and/or by adding (c) a promoter/ a poison/a modifier, and finally, and not less important, modifying the reaction temperature. Examples of the factor (b) are: mesoporous [6] and siliceous [7] materials, a pumice [8], carbons [9], and hydrotalcite [3]. Cases of factor (c) are the typical Lindlar catalyst (palladium heterogenized on calcium carbonate poisoned by lead acetate or lead oxide, Pd-CaCO 3 -Pb) [10] and the presence of quinoline and triphenylphosphine [11,12].…”

Terminal and Non Terminal Alkynes Partial Hydrogenation Catalyzed by Some d8 Transition Metal Complexes in Homogeneous and Heterogeneous Systems

“…After that initial part, all of the systems have a similar shape with an increasing 3-hexyne total conversion, showing a maximum value of conversion to (Z)-3-hexene. There was also a relatively low amount of the side products: (E)-3-hexene formed either as initial product or via Z  E isomerization, and n-hexane (not plotted in Figure 6 because of the low values obtained and for the sake of clarity) produced either by hydrogenation of the alkyne or the alkene isomers [7,57]. Last but not least, [RhCl(TDA)3]/RX3 showed the lowest conversion values to the (E) isomer and to the alkane.…”

“…: by varying a) the active species or b) the support, and/or by adding c) a promoter / a poison / a modifier, and finally, and not less important, by modifying the reaction temperature. Examples of factor b) are: mesoporous [6] and siliceous [7] materials, a pumice [8], carbons [9], and hydrotalcite [3]. Cases of factor c) are the typical Lindlar catalyst (palladium heterogenized on calcium carbonate poisoned by lead acetate or lead oxide, Pd-CaCO3-Pb) [10] and the presence of quinoline and triphenylphosphine [11,12].…”

Kinetic Study of the Partial Hydrogenation of 1-Heptyne over Ni and Pd Supported on Alumina

“…Figure 3 also shows the profile of reduction of Ni/Al2O3 catalyst, the principal reduction peak begins at 700 K, finishes over 900 K and presents a maximum at 802 K which corresponds to the reduction of NiO (Ni 2+ species) interacting with the alumina [30]. The second peak of minor intensity is observed at higher temperatures (>1000 K), and corresponds to the reduction of nickel aluminates [31][32]. At the reduction temperature used during the preparation of the catalysts, the obtained TPR spectra suggest the presence of species Ni 2+ and Pd 0 on Ni/Al2O3 and Pd/Al2O3 catalysts, respectively.…”