Zr-Ni/Al2O3催化剂上苯由H2O2氧化直接氨基化制苯胺

用浸渍法制备了Ni／Al2O3和Zr-Ni／Al2O3催化剂，用于以过氧化氢为氧化剂的苯直接氧化胺化制苯胺反应，并对催化剂进行了程序升温还原、室温氧吸附和氢吸附及XRD表征，结果表明，我们所制的Ni基催化剂对苯胺的生成都有活性，加入Zr后，催化剂中Ni物种更分散，低温可还原物种增加，室温吸氧和吸氢能力都增强，反应活性和对目标产物的选择性增大，Zr一方面使Ni物种进一步分散，增大催化剂的吸氢量和表面可还原Ni物种，有利于C-H键的活化；同时Zr与Ni的相互作用，促进了低温可还原物种的生成，使催化剂室温吸氧量增大，有利于苯的氧化，这种Zr和Ni的协同作用提高了催化剂的活性和选择性，催化剂的制备方法影响Zr与Ni的协同作用，使含Zr的两个催化剂的活性和选择性显示出差异。

Study of the Synthesis of Aniline via direct Amination of Benzene with H2O2 Oxidation on Zr-Ni/Al2O3

Two Ni-Zr/Al2O3 catalysts were prepared by different impregnation procedures controlling the impregnation solutions containing the same amount of Ni and Zr in the present work. These Ni-based catalysts were used for the synthesis of aniline by direct amination of benzene with H2O2 oxidation under mild conditions, and characterized by temperature-programmed reduction, oxygen adsorption, hydrogen adsorption and XRD, using Ni/Al2O3 and Zr/Al2O3 prepared by controlling also the same Ni or Zr contents respectively as reference samples. The results of TPR and XRD indicated that the Ni species were highly dispersed on the catalysts and the reduction temperature of the catalysts shifted to much lower values when Zr species were introduced. The formation of low temperature reducible species was much more remarkable on the catalysts composed of both Zr and Ni. The oxygen and hydrogen adsorption capacities of Ni-Zr/Al2O3 catalysts increased comparing to Ni/Al2O3 and Zr/Al2O3. Furthermore, the Ni-Zr/Al2O3 catalysts dis- played higher activity and selectivity to aniline than Ni/Al2O3. The co-existence of Zr species and Ni species increased the oxygen and hydrogen adsorption capacity and the amount of low temperature reducible Ni species. The oxygen adsorption capacity of the samples was observed to be in coincidence with the reduction behavior, that is, the sample with remarkable reduction at low temperature showed high oxygen adsorption capacity. The nickel content of the catalyst was found closely related to C-H bond activation, and the selectivity of aniline was related to the percentage of exposed nickel atoms. The harmonious interaction of Zr and Ni improved the activity and selectivity of the catalysts, which was significantly affected by preparation procedure of the catalysts.