.cu / Of Sio <sub> 2 </ Sub> Catalyst Aniline And Ethylene Glycol Step Synthesis Of Indole Of The Study

Indole, one of the important organic fine chemicals, has been widely used in the field of industry, agriculture, pharmacy and so on. There are many routes to synthesize indole, of which one step synthesis of indole from aniline and ethylene glycol (EG) is the most economical one.In this dissertation, the preparation of supported copper catalyst was studied and the catalyst's performance was also examined in the reaction using aniline and EG as raw materials.It was found that the supported copper catalyst prepared by impregnation- calcinations-in situ reduction has shown high activity when Cu(NO3)i was used as the precursor and SiO2 as the support.When using Cu/SiO2 catalyst, the best results can be achieved under the following reaction conditions: T=325C ; P-0.1MPa; GHSV=1635 h-'1; aniline/EG=7; LHSV=0.4h-1;velocity of H2=35ml/min; velocity of water vapour =41ml/min. That is, the conversion of EG was 100% and the yield of indole can reach 88%, which is about 10% higher than the best result previously reported.The activity of catalyst depends on the loading amount of Cu. The yield of indole rises with the increase of copper loading in the range of 0-4.35wt%, attaining a maximum value (88%) when the copper content was 4.35wt%, and then declining with the increase of copper loading.The deactivation of Cu/SiO2 catalyst is rapid. XRD and TG characterization showed that the deactivation of the catalyst mainly originates from the carbonaceous deposits on the catalyst. Introducing steam and Ha into the reaction system could effectively refrain the deactivation of the catalyst. The introduction of steam can improve the selectivity of indolegreatly, the reason may be that it could restrain the side reactions of EG and promote the desorption of indole from the catalyst surface.The support SiOa used as the support of Cu is also concerned with the reaction. With the cooperation of SiO2 and Cu, indole can be readily formed from aniline and EG. Due to the acidity of catalyst, EG and aniline reacts by dehydration and produce the intermediate I -2-(o-aminophenyl) ethanol which produces another intermediate II (2,3- dihydroindole) on the surface of SiO2 or Cu. Most 2,3-dihydroindole formed the indole by dehydrogenation on Cu. 2,3-dihydroindole is apt to arise side reactions on the surface of SiO2. The routes of iodole synthesis from aniline and ethylene glycol on the Cu/SiO2 catalyst can be proposed as follows:Cu/SiO2 catalyst dotted by ZnO shows low activity in the synthesis of indole, which may be attributed to the interaction of ZnO and Cu. The selectivity of indole decreased when transition metal (Fe, Co, Ni, Mo, W, V, Ce, Cr) was introduced into the Cu/SiO2 catalyst. Acidic and alkaline (Na, K, Mg, Ba) promoter can improve the selectivity of indole, however, reduced the conversion of EG greatly.