纳米镍粉上硝基苯加氢制苯胺反应性能研究

以NiSO4.6H2O、NaOH和H2为原料,采用低温固相法制备了分布均匀、平均粒径为20～35 nm的纳米镍粉,并采用X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和X射线光电子能谱分析(XPS)等微观分析手段对产物表面结构和价态进行了表征。研究了纳米镍粉加氢还原硝基苯制备苯胺体系中温度、氢压力、催化剂用量等因素对转化率的影响,并与Raney Ni的活性做了比较。结果表明,纳米镍粉催化加氢活性高于RaneyNi,是同条件下Raney Ni的9倍左右;催化剂用量4wt%～6wt%(质量含量,下同),温度为120℃为还原的最佳条件;同时发现氢压力对转化率也有着较大影响,当压力达到0.8 MPa,硝基苯转化为苯胺的转化率高达76.42%。

Research on the Hydrogenated Conversion of Nitrobenzene to Aniline by nano-Ni

Nanosized nickel powders were prepared by solid-state reaction from NiSO4?6H2O and NaOH.The nickel power was characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),scanning electron microscopy(SEM),and X-ray photoelectron spectroscopy(XPS).The effect of the factors as temperature,H2 pressure and the amount of catalyst on the conversion of nitrobenzene to aniline was investigated to obtain the optimum operating condition.The comparison of hydrogenation activity between nanosized nickel powders and Raney Ni was done.The results showed that the nanosized powders showed better activity for the hydrogenation of nitrobenzene to aniline than that of Raney Ni.The better conditions of the experiment were the catalyst amount of 4%-6% and the temperature of 120 ℃.H2 pressure affects the conversion significantly.The conversion was 76.42% when H2 pressure was at 0.8 KPa.