Ligand modification of Ni-based catalysts by coordination of dicyandiamide to Ni metal leads to enhanced selectivity for the selective hydrogenation of halonitroaromatics.The selectivity of above 99.9%to aromatic halo...Ligand modification of Ni-based catalysts by coordination of dicyandiamide to Ni metal leads to enhanced selectivity for the selective hydrogenation of halonitroaromatics.The selectivity of above 99.9%to aromatic haloamines can be achieved at the conversion of 100%.The results of H_2-TPD and FT-IR experiments show that Ni^-H~＋ species possessing the properties of Lewis acid site on the surface of Raney Ni could be responsible for the hydrodehalogenation.When Raney Ni was treated by dicyandiamide,Ni^-H~＋ species interacted with N atom from the dicyandiamide.This interaction was stable even at reaction temperature,which reduced the possibility to form the intermediate state of Ar-Cl...H~＋Ni^-.And then C-Cl bond could not be polarized and activated.The hvdrodechlorination process was suppressed effectively.展开更多
基金the National Basic Research Program of China(973 Program)(No 2011CB710800)the National Natural Science Foundation of China(No20976164)
文摘Ligand modification of Ni-based catalysts by coordination of dicyandiamide to Ni metal leads to enhanced selectivity for the selective hydrogenation of halonitroaromatics.The selectivity of above 99.9%to aromatic haloamines can be achieved at the conversion of 100%.The results of H_2-TPD and FT-IR experiments show that Ni^-H~＋ species possessing the properties of Lewis acid site on the surface of Raney Ni could be responsible for the hydrodehalogenation.When Raney Ni was treated by dicyandiamide,Ni^-H~＋ species interacted with N atom from the dicyandiamide.This interaction was stable even at reaction temperature,which reduced the possibility to form the intermediate state of Ar-Cl...H~＋Ni^-.And then C-Cl bond could not be polarized and activated.The hvdrodechlorination process was suppressed effectively.
