ZnO对Ag/SiO2催化剂银的分散作用及对吲哚合成稳定性的影响

将ZnO助剂加到由苯胺和乙二醇一步合成吲哚的Ag/SiO2催化剂中,发现ZnO助剂能大大提高催化剂的稳定性.XRD和TEM表征首次得到:ZnO是结构型助剂,它能使银很好地分散在SiO2表面上,并可有效地抑制反应过程中银粒子的烧结.

Dispertion of ZnO to Ag in Ag/SiO2 Catalyst and Its Effect on the Stability of Indole Synthesis

Indole, which is an important raw organic material and fine chemical product, has many uses in the fields of industry, agriculture and medicine. There are many known methods to produce indole. One of the most promising routes, from an economic point of view, seems to be the direct catalytic synthesis from aniline and ethylene glycol. For the reaction, Ag/SiO 2 catalyst exhibits very high activity. However the activity of Ag/SiO 2 catalyst declined with increase of time on stream in the reaction. In order to improve the stability of the catalyst ZnO promoter was doped into Ag/SiO 2 catalyst. Cu/SiO 2-ZnO catalysts were prepared by separative impregnation method. It was found that ZnO could enhance the stability of the catalyst greatly. It was firstly obtained from the characterization of XRD and TEM that ZnO could efficiently improve the dispersion of silver on the support and inhibit the sintering of silver crystallite during the reaction process. ZnO is a structure promoter.