论文部分内容阅读
以苯胺和生物质来源的丙三醇为反应原料,在铁促进的Cu/SiO2-Al2O3催化剂上气相合成了3-甲基吲哚,采用X射线光电子能谱、氢气程序升温还原(H2-TPR)、X射线衍射、透射电子显微镜、电感耦合等离子体发射光谱(ICP)、氨程序升温脱附(NH3-TPD)以及热重(TG)分析等技术对催化剂进行了表征。结果表明,向Cu/SiO2-Al2O3催化剂加入铁助剂不仅能明显提高催化剂的活性和选择性,而且能大大改善催化剂的稳定性。在Cu-Fe/SiO2-Al2O3催化剂上,反应3 h,3-甲基吲哚收率能够达到48%,而且催化剂经过再生可以重复使用,即使反应43 h,其产物收率也没有明显的降低。各种表征表明,向Cu/SiO2-Al2O3加入铁助剂能增强铜和载体之间的相互作用,由此大大提高了铜粒子在载体表面的分散度,并且有效减少了反应过程中铜组分的流失;此外,铁助剂还能显著减少催化剂的中强酸中心数,增加弱酸中心数,从而提高3-甲基吲哚的选择性,并且抑制了积炭的形成。
In this work, 3-methylindole was synthesized on iron-promoted Cu / SiO 2 -Al 2 O 3 catalyst using glycerol as precursor and aniline and biomass as raw materials. X-ray photoelectron spectroscopy, hydrogen temperature programmed reduction ), X-ray diffraction, transmission electron microscopy, inductively coupled plasma atomic emission spectrometry (ICP), ammonia temperature-programmed desorption (NH3-TPD) and thermogravimetry (TG) The results show that the addition of iron promoter to the Cu / SiO2-Al2O3 catalyst can not only significantly improve the catalyst activity and selectivity, but also greatly improve the catalyst stability. On the Cu-Fe / SiO2-Al2O3 catalyst, the yield of 3-methylindole can reach 48% after 3 h of reaction, and the catalyst can be reused after being regenerated. The yield of the product did not decrease obviously even after 43 h of reaction . Various characterizations show that the addition of iron additives to Cu / SiO2-Al2O3 enhances the interaction between copper and the support, thereby greatly improving the dispersion of the copper particles on the support surface and effectively reducing the copper content during the reaction In addition, the iron promoter can significantly reduce the number of medium strong acid sites and increase the number of weak acid sites, thereby increasing the selectivity of 3-methylindole and inhibiting the formation of coke.