Aluminosilicate zeolite ECR-1 was successfully obtained under hydrothermal condition at 100 ℃ by hydrothermal phase transition of zeolite Y in the absence of organic template.When n(Na2O)/n(SiO2)ratio in the starting aluminosilicate gel[n(SiO2)∶n(Al2O3)∶n(Na2O)∶n(H2O)=10∶1.0∶2.5—3.3∶200] was 0.33,the phase transition from zeolite Y to zeolite P occurred.However,when the n(Na2O)/n(SiO2)ratio was 0.25,zeolite Y was converted into zeolite ECR-1.In this case,zeolite Y was served as nutrient for the crystallization of zeolite ECR-1.
Aluminosilicate zeolites as one of the most important catalytic materials are widely applied in industrial reactions,and understanding of their synthetic mechanism is one of key factors in this field.27Al and 29Si NMR techniques are one of powerful tools for characterization of zeolite synthesis,but unfortunately the study on 27Al NMR spectra of aluminosilicate solutions is still argumentative,and the assignment of aluminosi-licate species in the solutions are challengeable.In this work,we have carefully compared 27Al NMR spectra of various aluminosilicate solutions,harmonizing the assignments reported previously.Furthermore,we assigned 29Si NMR spectra related to Al species.The peaks at δ:-75.1 and-82.5 in 29Si NMR spectrum are related to Q2 Al species,the peaks at δ:-84.5 and-90.8 are related to Q3 and Q4 Al species in aluminosilicate solutions,respectively.
利用水热合成法制备了一种新型硅酸锡微孔化合物(Microporous stannosilicates),通过XRD,SEM,29Si MAS NMR,119Sn MAS NMR,IR和TG等测试手段对该硅酸锡微孔化合物进行了表征.结果表明,该硅酸锡微孔化合物中的Sn物种为六配位形式,而此化合物与硅锆矿石(Litvinskite)具有相同的拓扑结构.
