Vapor-phase Catalytic Synthesis Of 3-methylindole From Aniline And Gylcerol

3-methylindole,an important indole derivative and intermediate,is widely used in the fields of medicine and spice. The dissertation reports a new method for the the direct vapor-phase synthesis of 3-methylindole from aniline and glycerol over Cu/SiO₂-Al₂O₃ catalyst. Comparing with conventional liquid-phase synthesis, the direct vapor-phase synthesis avoids using a large amount of expensive starting materials and toxic organic solvent.The catalysts were prepared by incipient wetness impregnation and investigated by means of XRD, H₂-TPR, NH3-TPD, BET and TG. The results indicated Cu/SiO₂-Al₂O₃ catalyst exhibited higher activity and selectivity. The copper was active species for the reaction. It's favor of the synthesis of 3-methylindole when the catalyst had the more numbers of weak acid center and copper had good dispersion. The factors such as the catalyst preparation conditions and the reaction conditions had been investigated. When the catalyst precursor was calcined at 500℃for 4 h with temperature-direct calcination method and reduced in-situ at 250℃for 2 h in mixture gas of H2 30 ml/min and N₂ 30 ml/min, the yield of 3-methylindole could be up to 46% under reaction temperature of 240℃and reaction mixture gas of 10 ml/min H₂, 58 ml/min N₂, 12 ml/min steam. The yield of 3-methylindole could be up to 35% after 40 h of reaction. The reasons of the catalyst deactivity are the sintering of copper particles and carbon-deposition of catalyst surface during the reaction.