【作者】 沙鹏艳；

【导师】 夏树伟；

【作者基本信息】 中国海洋大学 ， 应用化学， 2008， 硕士

【摘要】 胶体镍作为一种新型催化剂,在催化活性和选择性方面有着许多独特之处。本文采用化学还原法制备了胶体镍催化剂,并对其催化性能进行了考察。首先,详细研究了胶体镍的制备条件,并探索了胶体镍制备条件对催化丙烯腈加氢反应的影响。在没有保护剂和成核剂的条件下,用水合肼作还原剂和体系pH调节剂,乙二醇作溶剂,通过化学还原法制得了高分散、窄分布并能在空气中稳定存在的纯净胶体镍催化剂。系统研究了还原剂用量、体系pH值、反应物初始浓度、还原温度、反应时间和加料方式对胶体镍催化性能的影响,确定了较佳制备条件,即[N2H4]/[Ni²⁺] = 8,pH = 8～9,[Ni²⁺] =10 mmol/L,T = 90℃,反应3 h,向体系中滴加Ni²⁺溶液。其次,利用紫外-可见吸收光谱（UV-vis）、X射线衍射（XRD）和透射电子显微镜（TEM）等分析手段对胶体镍的物相、形貌及大小进行了表征。最后,以较佳条件下制得的胶体镍为催化剂,考察了丙烯腈加氢反应中催化反应压力、反应物浓度、反应温度和反应时间对胶体镍催化活性和选择性的影响。在优化催化条件下,即氢压5.0 MPa、温度70℃、反应时间3 h,丙烯腈的转化率和丙腈的选择性分别高达96%和100%,表现出了较高的催化活性和优良的选择性。更多还原

【Abstract】 As a new type of catalytic material, colloidal nickel catalyst has some special properties in catalytic activity and selectivity. In this paper, the catalytic performance of colloidal nickel catalyst which is prepared by chemical reduction is studied .Firstly, preparation conditions of colloidal nickel are studied and influence of preparation conditions on catalytic hydrogenation of acrylonitrile is explored. In the absence of protective agent and nucleating agent, the pure colloidal nickel catalysts with high dispersion and narrow distribution are gained by reducing nickel ion with hydrazine in glycol. The effects of reductant quantity, pH values, reactant concentrations, temperature, reaction time and mixing style to the catalytic performance of colloidal nickel catalyst are reviewed. The optimal preparation conditions are: [N₂H₄]/[Ni²⁺] = 8, pH = 8～9, [Ni²⁺] =10 mmol/L, T = 90℃, 3 h, adding Ni²⁺ solution dropwise.Secondly, the substance, shape and size are respectively affirmed by UV-vis, XRD and TEM.Lastly, the effects of reductive reaction conditions such as H2 pressure, reaction temperature, acrylonitrile concentration and time on the catalytic performance of colloidal nickel which is prepared under the optimal conditions are investigated. Under the optimized reaction conditions of H2 pressure 5.0 MPa, 70℃, concentration of acrylonitrile 1.7 mol·L-1 and 3 h, conversion of acrylonitrile and selectivity of propionitrile achieve 96% and 100% respectively. Colloidal nickel displays good catalytic performance in the hydrogenation of acrylonitrile.更多还原