Further Studies on Aluminophosphate Molecular Sieves Part 1 . - AIPO , - HS : A Hydrated Aluminophosphate Molecular Sieve

Pure, highly crystalline AIPO,-H2 is synthesized from an aluminophosphate gel containing dipentylamine and characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetry and solid-state nuclear magnetic reson!nce spectroscopy. The AIPO,-H2 structure has orthorhombic symmetry with cell parameters of a = 16.184(5) A, b = 9.914(3) A and c = 8.134(4) A. It is constructed exclusively from hydrated triple crankshaft chains that also build the 18-membere! ring Vyl-5. AIPO,-H2 is a microporous, hydrated aluminophosphate with highly elliptical 10-ring channels (2.9 A by 7.6 A). One third of the framework Al atoms are octahedrally coordinated to two water molecules and four framework oxygens. Since AIPO,-H2 and VPI-5 share the same structural building unit, some of their physicochemical properties are similar. The existence of AIP04-H2 and VPI-5 suggests that other molecular sieves with the same type of building unit can be synthesized.