Aluminophosphate VPI

The most obvious approach to obtain controlled mesoporosity is the extension of zeolite-like three-dimensional framework structures to larger pore-sizes. Zeolite-like compounds in the micro- and mesoporous range are the aluminophosphate VPI-5, cloverite and ULP (MCM-41). These new materials are characterized by pore diameters between 1.3 nm and 20 nm. 

With the growing interest in nanochemistry (Ozin, 1992), many attempts have been made in recent years to prepare porous crystals having larger channel widths than those in the aluminosilicate zeolites (i.e. 0.8 nm). In particular, great excitement was generated by the preparation of the wide-pore aluminophosphate, VPI-5, by Davis and his co-workers in 1988 and again when the first member of a new group of mesoporous molecular sieves , MCM-41, was prepared by Mobil scientists in 1992. 

Crystallization of Aluminophosphate VPI-5 Using Magic Angle Spinning NMR Spectroscopy... 

In this report we will describe the use of variable temperature MASNMR spectroscopy to follow the crystallization of the aluminophosphate, VPI-5. The results of the in-situ experiments are compared to those obtained for VPI-5 S3mthesized in autoclaves by traditional methods. 

Kolodziejski W, Rocha J, He H.KlinowskiJ (1991) High resolution solid state H nuclear magnetic resonance spectra of organic template in hydrated aluminophosphate VPI-5. Appl Catal 77 L1-L8... 

Optimization of the synthesis of an ultra-large pore aluminophosphate VPI-5 using di-n-butylamine (n-DBA-VPI-5) has been done. The sample synthesized was characterized by XRD, SEM, FTIR, TGA-DTA, NMR and sorption studies. The extra-large pores (larger than lOA) in VPI-5 were confirmed by adsorption measurements. N2 adsorption at 77K shows mesopores with pore diameter of 36A alongwith the micropores of n-DBA-VPI-5. 

Figure 3 Schematic representation of the aluminophosphate VPi-5 lattice framework. (From Ref. 14.)...

Fig. 14. DOR NMR spectra of dehydrated (fop) and hydrated bottom) aluminophosphate VPI-5, recorded at 104.2 MHz with the rotation frequency of the outer DOR rotor of v (=800 Hz and rotor-synchronized pulses [116]...

Extra-large-pore zeolites (at least 14-membered rings with pore sizes around 1.0 nm)—e.g., aluminosilicates CIT-5, UTD-1. aluminophosphates (VPI-5, JDF-20, gallophosphate. cloverite). 

Figure 2. Structure of the microporous aluminophosphate VPI-5 as viewed along the z-axis. Tetrahedra represent the alternating aluminium and phosphorous cations, cross-linked by comer sharing at oxygen anions.

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