An efficient green protocol for the synthesis of tetra-substituted imidazoles catalyzed by zeolite BEA: effect of surface acidity and polarity of zeolite
作者:Jenifer J. Gabla、Sunil R. Mistry、Kalpana C. Maheria
DOI:10.1039/c7cy01398a
日期:——
controlled dealumination. The synthesized materials were characterized by various characterization techniques such as XRD, ICP-OES, BET, NH3-TPD, FT-IR, pyridine FT-IR, 27Al and 1H MAS NMR. It has been observed that the dealumination of the parent zeolite H-BEA (12) results in the enhanced strength of Brønsted acidity up to a certain Si/Al ratio which is attributed to the inductive effect of Lewis acidic
在本研究中,研究了各种介质(H-ZSM-5)和大孔(H-BEA,HY,H-MOR)沸石作为固体酸催化剂的催化活性。发现H-BEA沸石是一种可通过NH-苄基苯之间的一锅,四组分反应(4-CR)合成1-苄基-2,4,5-三苯基-1 H-咪唑的有效催化剂4 OAc,取代的芳族醛和苄基胺。通过控制脱铝可以很好地改善BEA分子筛的疏水性,Si / Al比和酸性。合成的材料通过各种表征技术进行表征,例如XRD,ICP-OES,BET,NH 3 -TPD,FT-IR,吡啶FT-IR,27 Al和1H MAS NMR。据观察,母体H-BEA沸石(12)的脱铝导致布朗斯台德酸度的强度提高到一定的Si / Al比,这归因于路易斯酸性EFAl物质的诱导作用,导致较高的沸石BEA(15)催化剂对1-苄基2,4,5-三苯-1 H合成的催化活性;-咪唑类在无热溶剂的条件下具有良好至极好的收率。使用本发明的催化合成方案