M. Haouas et al., IN-SITU NMR-STUDY OF HYDROTHERMAL SYNTHESIS OF A TEMPLATE-MEDIATED MICROPOROUS ALUMINOPHOSPHATE MATERIAL - ALPO4-CJ2, Journal de chimie physique et de physico-chimie biologique, 95(2), 1998, pp. 302-309
To elucidate the formation mechanisms of crystalline microporous mater
ials prepared under hydrothermal conditions, one needs to observe the
hydrothermal medium while the material forms. One of the main objectiv
es is to investigate whether the condensed phase forms from the assemb
ly of molecular precursors in solution or from a solid phase transform
ation. Therefore, In situ NMR was carried out to observe species prese
nt in solution. The study was applied to formation of an amine-mediate
d microporous oxyfluorinated aluminophosphate christened AlPO4-CJ2. In
situ P-31, N-14, Al-27, and F-19, NMR study under hydrothermal condit
ions at 423K allowed us to follow pH evolution during the synthesis an
d to propose the structure of species in solution.