Ni/SiO_2和SO_3H-C/SBA-15复合催化剂上硝基苯加氢制对氨基苯酚

Catalytic hydrogenation of nitrobenzene to p-aminophenol over Ni/SiO_2 and SO_3H-C/SBA-15 solid acid mixed catalyst

将Ni/SiO2催化剂与磺酸功能化的C/SBA-15固体酸(SO3H-C/SBA-15)混合用于催化硝基苯制对氨基苯酚的反应,考察了二者的质量比、反应压力和温度、搅拌速度和反应时间等对反应性能的影响,采用X射线衍射、H2程序升温脱附、透射电镜、N2吸附-脱附、红外光谱和热重分析对催化剂进行了表征.结果表明,Ni/SiO2上活性中心分布均匀,碳含量为40%的SO3H-C/SBA-15上固体酸酸值最大.当Ni/SiO2和SO3H-C/SBA-15质量比为1:6时,反应活性较好;在120oC,0.6MPa和搅拌速度1200r/min的条件下反应3h,硝基苯转化率为85.1%,对氨基苯酚选择性为23.8%.与文献中大多数采用Pt和固体酸混合用作催化剂时相当.

Mechanical mixed catalysts comprised of 20% Ni/SiO2 and carbon-silica mesoporous composite functionalized with sulfonic acid groups（SO3H-C/SBA-15） were used for hydrogenation of nitrobenzene to p-aminophenol.The effects of the mass ratio of Ni/SiO2 to SO3H-C/SBA-15,reaction pressure,temperature,stirring speed,and reaction time were examined.The catalysts were characterized by X-ray diffraction,H2 temperature-programmed desorption,transmission electron microscopy,infrared spectroscopy,and thermal gravity analysis.The results indicated that Ni is uniformly dispersed on the support,forming a single active center.The SO3H-C/SBA-15 solid acid with 40% carbon content exhibits the highest acid density.The mixed catalyst with a Ni/SiO2 to SO3H-C/SBA-15 mass ratio of 1：6 shows the highest activity.Under optimized reaction conditions of a reaction temperature of 120°C,reaction pressure of 0.6 MPa,stirring speed of 1200r/min,and reaction time of 3h,the nitrobenzene conversion of 85.1% and p-aminophenol selectivity of 23.8% were obtained.The reaction result is comparable with those on most mixed catalysts containing Pt and solid acid reported in the literature.