甲胺改性酸碱双功能Y沸石的制备和表征

摘要

An acid-basic bifunctional amine-hybrid H-Y zeolite has been hydro-thermally prepared at 416 K with methylamine solution as a modifier.Characterized with X-ray powder diffraction (XRD) and solid state ~(29)Si magic-angle spinning nuclear magnetic resonance (~(29)Si MAS NMR),the obvious increase of cell volume and the appearance of new Si-N bonds in the framework have been observed.The acid-basic properties of the hybrid zeolite,investigated with TG/DTG/DTA and NH_3-TPD or CO_2-TPD,have been proved to be greatly enhanced.As pre-calcination at different temperatures,the acid amount and basic amount of the modified zeolite increase 3 to 7 times and 1.5 to 26 times respectively,in comparison with those of H-Y zeolite.%以甲胺水溶液为改性剂,H-Y沸石可在416 K下经水热反应制备酸碱双功能甲胺杂化H-Y沸石.X射线粉末衍射(XRD),固体~(29)Si魔角核磁共振(~(29)Si MAS NMR)表征表明甲胺分子与H-Y相互作用导致沸石晶胞体积明显增大,骨架产生新的Si-N键.以热重(TG/DTG)及差热分析(DTA),NH3,CO_2程序升温脱附(NH3-TPD和CO_2-TPD)研究杂化H-Y沸石的酸-碱性质及其经不同温度焙烧后的变化,结果表明,杂化后沸石的酸/碱量,尤其是后者增加甚大.与H-Y相比,随焙烧温度变化,该酸-碱双功能沸石材料的酸/碱量可分别提高3至7倍和1.5至26倍.