Cooperative structure-directing effect in the synthesis of aluminophosphate molecular sieves in ionic liquids

Abstract

In situ two-dimensional NMR and fluorescence emission spectroscopy were employed to investigate the cooperative structure-direction effect of organic amine such as morpholine in the synthesis of aluminophosphate molecular sieves in ionic liquids. In situ rotating frame nuclear Overhauser effect spectra (ROESY) together with fluorescence measurements demonstrate that the aggregates between imidazolium cations and morpholines through intermolecular hydrogen bonds can be formed in the gel during the crystallization of molecular sieves. Combining with the characterizations of the solid products by solid-state NMR, it is verified that different aggregates of organic amines with imidazolium cations, which is similar to self-assembled supramolecular analogues, could act as the structure-directing agents for selective tuning of the framework topologies such as AEL, AFI and LTA in the final solid products.

Controlled Synthesis of Polyions of Heavy Main-Group Elements in Ionic Liquids

“…In addition, the interplay of ILs with additives or directing agents has to be investigated further. Therefore, either in situ reaction monitoring [60,61,62] or comparisons of several syntheses can elucidate the influence of ILs. The present review article aims to highlight a variety of reaction parameters and techniques for the directed synthesis of polyions of heavy main-group elements (fourth period and beyond) in ILs (cation and anion abbreviations in Table 1) in order to provide researchers with an insight into promising synthetic approaches.…”

Probing ZnAPO-34 Self-Assembly Using Simultaneous Multiple in Situ Techniques

“…Under nonhydrothermal conditions, this question becomes even more pertinent. [9][10][11][12] To date, a number of in situ crystallization studies probing microporous aluminophosphate synthesis exist, the majority of which focus on (Co)APO-5 (AFI structure). These studies utilize mostly scattering methods for probing the onset of crystallization, although many also employ spectroscopic techniques allowing for atomic/molecular insight into the self-assembly process.…”

Synthesis of aluminophosphate by the ionothermal method using factorial design

“…However, at a high %EU, in which there is an excess of SDAs, high t c values provide solids with high crystallinity and low ion exchange capacity which could be explained by the small microporous structure of the GIS topology and AlPO-CJ2. Also, this probably impedes the balance cation allocation and generates lower charge density in the framework [9,11]. In short, the results showed that crystallization is an extremely complex process involving the interaction and competition between the solvent, template and framework formation.…”

“…These liquids and eutectic mixtures are formed by fused salts (generally formed using organic cations and inorganic anions) at close to ambient temperatures and they can act either as solvents or templates during the synthesis of molecular sieves [2,3]. Although ionothermal synthesis is a potential technique to prepare microporous materials, such as aluminophosphates (AlPOs) [4][5][6][7][8][9][10][11][12][13], the role of the several synthesis parameters in the structure and properties of the zeotype must be well understood.…”