Inorganic aluminophosphates

Mesostructured aluminophosphate / surfactant composite materials were prepared from aqueous and alcoholic systems. Syntheses in ethanol or methanol, respectively, lead to mixtures of two nanostructured phases. One of these consists of hexagonally arranged rod-like assemblies of the surfactant molecules with the head groups located in the centres, encapsulating the inorganic aluminophosphate the other is lamellar. The syntheses were monitored by in-situ temperature- and time-resolved small angle X-ray scattering (SAXS). 

Sveshnikova, V. N. Zaitseva, S. N. (1964). Aluminophosphates as polyelectrolytes. Russian Journal of Inorganic Chemistry, 9, 672-5. 

S. Feng and T. Bein, Vertical aluminophosphate molecular sieve crystals grown at inorganic-organic interfaces. Science 265, 1839-1841 (1994). 

In conclusion, the synthesis of mesostructured aluminophosphate / surfactant materials in alcoholic systems yields a mixture of an inverse hexagonal and a lamellar phase, the latter of which is more stable, as its formation is relatively favoured by higher temperatures and/or longer reaction times. The synthesis is highly cooperative the surfactant / alcohol systems without the inorganic species do not show any lyotropic behaviour. 

Zeolites and related aluminosilicates constitute a vital family of microporous materials with immense applications in catalysis, sorption and separation processes [1-3]. The discovery of aluminophosphates is an important landmark in the science of these materials [4], All these materials are, in general, synthesized under hydrothermal conditions by making use of template molecules [2]. The template molecules are usually organic amines and they are involved in the formation of these framework structures in more ways than one. While it is difficult to pinpoint the exact manner in which the amines participate or direct the formation of these inorganic structures, it is generally believed that their size and shape are crucial in determining the pore structure. In recent years, a variety of open-framework structures formed by divalent metal phosphates... 

Aluminophosphate Molecular Sieves A New Class of Microporous Crystalline Inorganic Solids... 

Further variation of the stmctural and catalytic properties of four-coimected tetrahedral frameworks is obtained by the substitution of silicon or metal cations,giving materials known as SAPO s and MeAPO s, respectively. More than twenty metal aluminophosphate frameworks have been identified with Mg, Mn, Fe, Co, or Zn substituents. These give the possibility of framework redox activity (e.g. Fe +/Fe +) in catalysis as well as the usual Bronsted acidity. For further information about zeolitic and microporous phosphate frameworks see Porous Inorganic Materials and Zeolites) and recent reviews. ... 

The entrapment-type nanocomposites can be prepared from zeolites and they are of two types zeolite-inorganic and zeolite-organic. Zeolite crystals are three-dimensionally linked network structures of aluminosilicate, aluminophosphate (ALPO), and silicoaluminophosphate (SAPO) composition and are porous, the pores being in the range of 2.8 to 10 A. Many of the highly siliceous, ALPO, and SAPO zeolites have been synthesized using organic templates such as tetrapropyl... 

As mentioned earlier in this chapter, it is the social demands and wide applications of porous materials that keep them under continuous exploration. From natural zeolites to synthesized ones, from low-silica zeolites to high-silica ones, from aluminosilicate molecular sieves to aluminophosphate-based ones, from extra-large microporous materials to mesoporous materials, and from inorganic porous frameworks to MOFs, together with newly emerging macroporous materials, all these porous materials have ordered and uniform porous systems. 

Figure 3.21 The correlation between the charge/volume ratio of the organic species and the charge density of the inorganic framework of the anionic aluminophosphate chains with Al/P ratio of 1/2 (a), of the anionic aluminophosphates with Al/P ratio of 1/2 directed by arylamines (b), of the anionic aluminophosphates with Al/P ratio of 2/3 directed by cyclic amines (c), of the layered anionic aluminophosphates with Al/P ratio of 3/4 and 4,6,8-net topological sheet structure directed by chain-shape alkylamines (d), and of the layered anionic aluminophosphates with Al/P ratio of 3/4 and 4,6,12-net topological sheet structure directed by chain-shape alkylamines (e)...

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