NaY沸石超笼中合成12-钼磷杂多酸  

Synthesis of 12-Molybdophosphoric Acid in the Supercage of Zeolite NaY

作　　者：郭麦平[1] 王军[1] 周华兰[1] 任晓乾[1] 

机构地区：[1]南京工业大学化学化工学院材料化学工程国家重点实验室,南京210009

出　　处：《化学学报》2008年第10期1159-1162,共4页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20476046);高校博士点基金(No.20040291002);江苏省"青蓝工程"学术带头人资助项目

摘　　要：针对负载杂多酸催化剂在极性反应体系中活性组分易溶脱的难题,用"瓶中造船(ship in the bottle)"的方法在NaY沸石超笼中合成了12-钼磷酸.将机械混和的MoO3晶体和NaY沸石在高温下焙烧,使MoO3在沸石表面高度分散,以此复合物在磷酸水溶液中反应,得到的固体样品用X射线衍射仪(XRD)、31P核磁共振谱(31PNMR)和红外光谱(IR)进行了表征,并测试了其在醋酸和正丁醇的酯化反应中的催化性能.结果表明,MoO3质量分数为10%的MoO3/NaY中载体仍保持Y沸石的结构,以此为原料合成的样品呈现出Keggin结构杂多酸的红外特征峰,并且在核磁共振磷谱中杂多酸的化学位移峰向负值方向发生了较大程度的位移,说明杂多阴离子与Y沸石羟基发生了强相互作用,样品在醋酸与正丁醇的酯化反应中显示出了较高的催化活性和优异的重复使用性能.这些充分说明在NaY沸石超笼中成功合成了12-钼磷酸。To solve the serious leakage problem of supported heteropoly acid catalysts in polar reaction media, 12-molybdophosphoric acid was encapsulated in the supercage of zeolite NaY by the ＂ship in the bottle＂ synthesis, which was carried out in aqueous slurry of phosphoric acid and the NaY supported MoO3 that was obtained by precalcinating the solid mixture of MoO3 and NaY at 773 K so as to achieve a highly dispersed MoO3 on the surface of NaY zeolite. The obtained solid sample was characterized by XRD, 31p NMR and IR, and its catalytic activity in the esterification of acetic acid with n-butanol was tested, showing that for MoO3/NaY with the MoO3 loading of 10% by weight （10% MoO3/NaY）, the support retains the microstructure of Y zeolite. The obtained sample synthesized from 10% MoO3/NaY exhibits the typical IR peak assigned to Keggin-structured heteropoly acid, and in ^31P NMR spectra the chemical shift for heteropoly acid in the sample shifts largely to a low value compared with the pure 12-molybdophosphoric acid due to the strong interaction between heteropoly anions and hydroxyls in zeolite Y. Moreover, the sample shows the high catalytic activity and excellent reusability in the esterification reaction, demonstrating that 12-molybdophosphoric acid has been successfully produced in the supercage of NaY zeolite.

关 键 词：NAY沸石 12-钼磷酸 瓶中造船 酯化 

分 类 号：O643.36[理学—物理化学]