类水滑石CuNiAl的制备、表征及其催化性能的研究

采用水热法和尿素水解法首次合成了三元类水滑石CuNiAl(Cu+Ni/Al=3,Cu/Ni=5.0,3.0,1.0,0.33),将合成的类水滑石用于苯羟基化反应。采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)和透射电镜(TEM)等手段对类水滑石进行表征,以CuNiAl31作为催化剂,考察了反应时间、反应温度、溶剂及溶剂用量、催化剂用量、n(benzene)/n(H_2O_2)对苯羟化反应的影响。结果表明:与CuNiAl11、CuNiAl21、CuNiAl13催化剂相比,CuNiAl31具有较高的反应活性,反应的最佳条件为:反应时间6h、反应温度65℃、15 ml吡啶作为溶剂、10mg催化剂、n(benzene)/n(H_2O_2)=3.0时,苯的转化率为7%,苯酚的选择性几乎为100%。

Preparation and characterization of CuNiAl hydrotalcites and their catalytic performances

CuNiAl ternary hydrotalcites with a（Cu＋Ni）/Al atomic ratio of 3.0 and a Cu/Ni atomic ratio of 5.0,3.0,1.0,0.33,were synthesized by both urea hydrolysis and hydrothermal synthetic conditions.The catalysts was characterized by XRD,FT-IR,SEM and TEM.Compared with the catalysts CuNiAl11,CuNiAl21,CuNiAl51 and CuNiAl13,CuNiAl31 showed an excellent catalytic activity.The effect of solvent,optimal amount of catalyst,molar ratio of benzene to H_2O_2,reaction temperature and time were also investigated using CuNiAl31 catalyst.The results showed that benzene conversion was 7%,phenol selectivity is nearly 100%in the condition of as solvent,10mg catalyst,n（benzene）/n（H_2O_2）=3,reaction temperature 338K,reaction time 6h.