Synthesis of mesostructured lamellar aluminophosphates in the presence of alkylpyridinium cationic surfactant

A series of mesostructured lamellar aluminophosphates and silicoaluminophos phates have been synthesized hydrothermally using alkylpyridinium bromide s urfactant templating or mixed surfactants of alkylpyridinium and cetyltrime thylammonium bromide. The synthesis of present aluminophosphate-based mesos tructured materials can be performed within the following molar gel composi tion: Al2O3:(0 8-1.9) P2O5:(0.3-1.0) CPBr:(0.8-4.2) TMAOH:(100-350) H2O:(0- 1.0) SiO2 at various temperatures in the range of 80-150 degreesC for 0.5-4 days. The effect of various synthetic factors, such as P/Al ratio, TMAOH/A l ratio, water content, surfactant concentration, synthesis temperature, an d reaction time, has been discussed. The addition of Si in the mixture gel requires more base content. The interlayer distance of materials decreases with either increasing water content in the reaction mixture or decreasing alkyl chain length of the templating surfactant alkylpyridinium cation. The mesostructured aluminophosphate-based materials were also prepared with te mplates mixtures of cetylpyridinium bromide and cetyltrimethylammonium brom ide. and their interlayer distance of materials can be finely controlled by changing the CPBr/CTABr molar ratio. Al-27 and P-31 nuclear magnetic reson ance spectra have been carried out to understand the local atomic arrangeme nts and coordination environments of these solid products. (C) 2001 Elsevie r Science B.V. All rights reserved.