介孔磷钨酸铯盐的液相组装及酸性研究  

Liquid Phase Assembly of Mesoporous Cs_(x)H_(3−x)PW_(12)O_(40) and Characterization of Their Acidity

作　　者：王美银 黄道丰 陈欣 周俊夫 任远航[1] 叶林[1] 岳斌[1] 贺鹤勇[1] WANG Meiyin;HUANG Daofeng;CHEN Xin;ZHOU Junfu;REN Yuanhang;YE Lin;YUE Bin;HE Heyong(Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials,Fudan University,Shanghai 200438,China)

机构地区：[1]复旦大学化学系,上海市分子催化与功能材料重点实验室,上海200438

出　　处：《高等学校化学学报》2021年第9期2734-2741,共8页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:22088101);国家重点研发计划项目(批准号:2017YFB0602204);中国石油化工股份有限公司研究项目(批准号:420068-2)资助。

摘　　要：以磷钨酸(H_(3)PW_(12)O_(40))和氯化铯(CsCl)为原料,两亲型三嵌段共聚物F127为模板剂,按不同的Cs/P比制备了一系列介孔磷钨酸铯盐(Cs_(x)H_(3)−xPW_(12)O_(40),m-CsPW).通过X射线粉末衍射(XRD)、场发射扫描电子显微镜(FES⁃EM)、场发射透射电子显微镜(FETEM)、N_(2)吸附-脱附测试和小角X射线散射(SAXS)等手段对所得样品进行了表征.结果表明,样品是由纳米微晶组装而成的晶态介孔材料.以三甲基膦为探针分子,通过^(31)P魔角旋转固体核磁共振波谱(^(31)P MASNMR)测定了样品酸处理前后的酸密度和酸强度.以5,7-二羟基-4-甲基香豆素的Pech⁃mann缩合反应为模型反应,考察了样品的酸性质与催化活性之间的关系.A series of mesoporous Cs_(x)H_(3)−xPW_(12)O_(40)samples(denoted as m-CsPW)has been prepared using H_(3)PW_(12)O_(40),CsCl as raw materials and amphiphilic triblock copolymer F127 as template.The sampleswere characterized by means of powder X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),field emission transmission electron microscopy(FETEM),N_(2)adsorption-desorption measurement and small angle X-ray scattering(SAXS)spectroscopy.The results indicate that the m-CsPW particles consis-ting of crystallographically ordered nanocrystallites are mesoporous spherical materials.Acid density and strength of the samples before and after acid treatment were characterized by^(31)P magic-angle spinning NMR spectroscopy(^(31)P MAS NMR)using trimethylphosphine as probe molecule.Taking the Pechmann condensation of 5,7-dihydroxy-4-methylcoumarin as a model reaction,the relationship between the acid properties of the samples and the catalytic activity of the reaction has been investigated.

关 键 词：介孔多酸盐 ^(31)P魔角旋转固体核磁共振波谱 酸性 Pechmann缩合 

分 类 号：O614[理学—无机化学]