The selective hydrogenation of halogenated nitrobenzene (HNB) has been a great important chemical reaction in the fine chemical productions. In this study, the effect of metal particle size on the selective hydrogenation of HNB over Pd/C catalysts has been extensively investigated through the combination of theoretical (density functional theory calculations, DFT) and experimental methods. DFT calculations showed that the reaction barriers for dechlorination strongly depend on the type of reaction sites (terrace or edge), while the hydrogenation reaction barriers are nearly the same on different sites, which indicates that Pd nanoparticle size significantly affects the catalyst selectivity. Moreover, Pd nanoparticles with different sizes (from 2.1 to 30 nm) supported on activated carbon were synthesized using the methods developed by our group. In a 500 mL reactor, the selectivity is over 99.90% when the Pd nanoparticles are bigger than 25 nm. Finally, the industrial applications of the proposed catalyst were evaluated in several pilot factories. This study provides useful information on controlling the selectivity of other similar reactions catalyzed by noble-metal nanocatalysts.

The activated carbon was pretreated with different concentrations of HNO 3 (from 0.5 to 67%). The amount and type of oxygen-containing groups on the activated carbon were determined with the adsorption neutralization method and temperature-programmed desorption (TPD) of CO and CO 2 ; furthermore, the density of total acidity (DTA) has been proposed. The Pd particle size of Pd/C catalysts was measured by X-ray diffraction patterns (XRD), CO chemisorption, and TEM. The experimental results indicated that the amount of oxygen-containing groups and the total acidity on the activated carbons, the Pd particle size and catalytic activity of Pd/C catalysts are highly dependent upon the HNO 3 concentration used in the pretreatment. The pretreatment of activated carbon with a low concentration of HNO 3 can increase the structure parameters due to removal of the impurities, will be beneficial to create an appropriate DTA environment, and will further improve the Pd dispersion and the catalytic activity of Pd/C catalysts. The highest catalytic activity and the finest Pd particle of Pd/C catalysts can be reached at 2.5% concentration of HNO 3 . A too-large amount of oxygen-containing groups assembling densely on the activated carbon will influence the Pd dispersion on the activated carbon well.

It is shown here for the first time that diethyl azodicarboxylate promotes dehydrogenation of tertiaryamines to afford enamines, which subsequently take place in tandem reactions with sulfonyl azides to give the N-sulfonyl amidine derivatives. A number of different substituted tertiaryamines and sulfonyl azides can successfully be coupled, and several functionalized groups are tolerated in this system. The reaction described here is mild, general, and efficient, thus providing an extremely preferable method for synthesis of a variety of N-sulfonyl amidine derivatives.

The first example of an iron-mediated direct Suzuki-Miyaura reaction between N-heterocyclic compounds and arylboronic acids is described, and both electron-rich and electron-deficient heteroarenes can be successfully used for the coupling reaction.

The hydrogenation of phenol to cyclohexanol under mild conditions (∼340 K) was achieved over Raney Ni catalyst in the aqueous phase. The adsorption-desorption properties of the reactants (phenol and H 2 ) and the products (cyclohexanone and cyclohexanol) on the Raney Ni catalyst are different in the aqueous phase and the organic phase. The hydrogenation rate of phenol is improved because the Raney Ni catalyst adsorbs more H 2 and phenol in water than in methanol. Meanwhile, the higher uptakes of H 2 and the lower desorption rates for cyclohexanone on the Raney Ni catalyst in the aqueous system result in the further hydrogenation of cyclohexanone to cyclohexanol.