Study On The Synthesis Of 3-methylindole From Glycerol And Aniline Over The Catalysts Of Cu/MIL-101 And Cu/MIL-101-MgO

3-Methylindole,an important fine chemical raw material,has been widely used in various fields such as industry,agriculture and medicine.The synthesis of 3-methylindole in an efficient,cheap and green way has became a very important topic.At present,it seems to be the best way for the synthesis of 3-methylindole from glycerol and aniline because it is green and cheap,and satisfies the atomic economic principle of chemical reaction.This paper mainly studied the reaction about the synthesis of 3-methylindole from glycerol and aniline over the catalysts of Cu/MIL-101 and Cu/MIL-101-MgO.MIL-101 was synthesized by hydrothermal method.Copper based catalysts were prepared by equal volume impregnation method.The catalysts were evaluated through the gas-solid phase reaction device at atmospheric pressure.MIL-101 support and Cu-based catalysts were characterized by XRD,H₂-TPR,NH₃-TPD,N₂ physical adsorption,SEM and TG techniques.Based on the detection on the type of Teflon-liner in autoclave and MIL-101 synthesis conditions such as composition and proportion of reaction raw materials,synthesis temperature and post-treatment methods,an ideal MIL-101 support with the crystal morphology of neat octahedral was obtained,which the specific surface area was 1458 m²/g,the pore volume was0.732 cm³/g,the main pores size was in 1.1³.1 nm,and the thermostable temperature exceeded350?.Moreover,the preparation conditions and reaction conditions of the Cu/MIL-101 catalyst has been investigated and Cu/MIL-101 catalyst exhibited high activity and selectivity when the support was impregnated for 4 h in the DMF solvent at room temperature,the catalyst precursor was reduced in situ for 3 h?N₂:H₂=20:20 mL/min?at 290?,and the catalytic reaction was carried out under the temperature of 240?and reaction gas ratio of N₂:steam:H₂=10:10:20?mL/min?.When Cu loading was 4.0 mmol/g,the yield of 3-methylindole reached 34%and selectivity was 51%.The performance of Cu-based catalyst was greatly improved by the addition of MgO.When the amount of MgO was 0.04 mmol/g,the yield of the target product reached 57%at the second hour.Various characterizations indicated that MgO can not only enhanced the interaction force between active component and support but also increased the number of weak acid centers,as a result,the dispersion of copper on the support was improved and the conversion of glycerol or the synthesis of 3-methylindole was promoted.In addition,MIL-101 can still maintain its crystal shape after loading active component or promotor,but the specific surface area and the pore size decreased slightly.