Influence Of HF On The Structure-directing Effect Of Diethylenetriamine And Ethylenediamine

In the synthesis of zeolites and related materials with open-framework, thestructure-directing agent is the most important factor. It has been demonstrated that thestructure-directing effect can be affected by many factors. However, how these factorsaffect or determine the structure-directing effect remains unclear. The nature of thetemplate effect or the structure-directing effect is not yet clearly understood.In this thesis, we investigated the influence of the HF on the structure-directing effectof ethylenediamine (en) and diethylenetriamine (deta).The presence or absence of F-did have significant influence on the structure-directingeffect of ethylenediamine (en) and diethylenetriamine (deta) in the synthesis ofopen-framework aluminophosphates.1. In the absence of F-, a three-dimensional (3D) open-framework aluminophosphateAl4P5O20(H2O)2C4N3H16(AlPO-CJ31) was synthesized from the initial mixture with themolar composition of Al2O3:4.0P2O5:3.0deta:153H2O under hydrothermal condition,while a one-dimensional (1D) aluminophosphate Al2P4O10(OH)3F C4N3H15(ty-1) wascrystallized from the same initial mixture in the presence of F-(molar composition: Al2O3:4.0P2O5:3.0deta:3.0HF:153H2O). Their crystallization processes were characterizedby X-ray powder diffraction (XRD), solid-state magic-angle spinning nuclear magneticresonance (MAS NMR) and elemental analyses. The results show that the fluoride canaffect the structure-directing effect of diethylenetriamine by altering the type anddistribution of the fragments formed in the synthetic system and the starting point (coreunit) of the crystallization, which will determine the structure of the resulting crystals.2. For ethylenediamine, layered aluminophosphate Al2P2O9NH3(CH2)2NH3(UiO-13)can be obtained from the initial mixture with the molar composition of Al2O3:1.5P2O5:18.0en:147H2O under hydrothermal condition, while layered aluminophosphateAlF(HPO4)·NH2(CH2)2NH2(1) was obtained from the initial mixture with the same molarcomposition (Al2O3:1.5P2O5:18.0en:3.0HF:147H2O) with the exception of F-. Weinvestigated the crystallization processes of these two compounds by XRD and the evolution of the concentrations of Al and P in the liquid phases. The results show that thefluoride can affect the structure-directing effect of ethylenediamine by altering the type anddistribution of the fragments formed in the synthetic system and the starting point (coreunit) of the crystallization, which will determine the structure of the resulting crystals. Thestructural properties of open-framework aluminophosphates AlPO-CJ31, ty-1, UiO-13and1were analyzed in detail and the influence of the F-on the structure-directing effect ofdiethylenetriamine and ethylenediamine was discussed. The results show that the fluoridecan affect the structure-directing effect of diethylenetriamine by altering the type anddistribution of the fragments formed in the synthetic system and the starting point (coreunit) of the crystallization, which will determine the structure of the resulting crystals.