改性Ni-B非晶态合金催化剂的制备与加氢性能研究

【作者】 张艳霞；

【导师】 白雪峰；

【作者基本信息】 黑龙江大学 ， 工业催化， 2010， 硕士

【摘要】 本文采用化学还原法,制备了一系列改性Ni-B非晶态合金催化剂。以硝基苯加氢还原制苯胺为探针反应,系统考察了制备条件对改性Ni-B催化剂的结构和催化加氢性能,优化了反应温度、压力与介质等加氢反应条件,确定了催化剂的最佳制备条件和反应条件,并利用XRD、DSC、SEM、XPS等分析方法对催化剂进行了表征。通过对Ni盐前驱体类型、KBH4溶液PH值、B／Ni比等制备条件的研究发现,在硝基苯加氢反应中,以Ni(Ac)2为镍源、KBH4溶液PH=12、B/Ni=2-2.5:1.溶剂为水制得的Ni-B催化剂较好。同时,添加少量的Mo、Co、La、Ce和P都不同程度地提高了Ni-B催化剂活性,其中以Ni-Mo-B催化剂的活性最佳。Ni-Mo-B催化剂最佳制备条件：Ni(Ac)2为镍盐、、KBH4溶液pH=12,Mo的添加量为Ni的5wt.%时,Mo是以M003的形式存在,M003的分散作用可防止Ni-B合金粒子的团聚,提高了催化剂比表面积,稳定了Ni-Mo-B催化剂的非晶态结构,此时苯胺收率为99.33%。另外还考察了反应压力、温度、介质、催化剂用量对上述制备的改性Ni-B催化剂活性的影响,以反应压力1.5 MPa,反应温度110℃,反应介质环己烷,催化剂用量0.2 g,反应4小时Ni-B催化剂苯胺收率最佳,可达99.87%。添加少量的Mo、Co、La、Ce和P的Ni-B催化剂中Ni-Mo-B催化加氢活性最佳,当以1.0 MPa、100℃、催化剂用量为0.20 g、反应介质环己烷为反应条件时,反应1.75 h Ni-Mo-B催化剂苯胺收率可达99.88%。更多还原

【Abstract】 A series of modified Ni-B amorphous alloys catalysts were prepared by the chemical reduction. The catalytic activities of the above catalysts were investigated through the hydrogenation reaction of nitrobenzene. The effect of preparation condition on the structure and performance of modified Ni-B were investigated, the reaction condition such as reaction temperature, pressure and amount of catalyst on hydrogenation reaction were optimized, the preparation condition and reaction condition of modified Ni-B catalysts were determined and the catalysts were charactered by XRD, DSC, SEM, XPS and so on.Researches on preparation condition such as Ni salt precursors, pH value of KBH4 solution, B/Ni ratio and etc found that Ni-B catalyst prepared by Ni (Ac) 2, pH value of KBH4 solution as 12, B/Ni ratio as 2～2.5:1, water as solvent was better. Meanwhile, Ni-B catalyst added with Mo, Co, La, Ce and P improved activity of Ni-B catalyst in different degree, especially Ni-Mo-B catalyst. The optimal preparation condition of Ni-Mo-B catalyst was Ni(Ac) 2, pH value of KBH4 solution as 12 and Mo adding amount as 5 wt.%of Ni. It was found that the addition of Mo as MoO3 in Ni-Mo-B catalysts reduced the aggregation of Ni-B alloy, increased specific surface area and stabled the structure of amorphous alloy, yield of aniline reached 99.33%. The influence of reaction pressure, temperature, medium and amount of catalyst was also investigated.The yield of aniline in 1.0 MPa、100℃.0.20 g catalyst, cyclohexane as solution reached 99.87% after 4 h. The hydrogenation activities of Ni-Mo-B amorphous alloy catalysts among modified Ni-B catalyst added with Mo, Co, La, Ce and P were optimized. The yield of aniline in 1.0 MPa、100℃、0.20 g catalyst, cyclohexane as solution reached 99.88% after 1.75更多还原