Synthesis of Mesostructured and Mesoporous Aluminum Organophosphonates Prepared by Using Diphosphonic Acids with Alkylene Groups

Mesostructured and mesoporous aluminum organophosphonates (AOPs) with 2-D hexagonal structures (AOP-2) can be synthesized by using alkylene diphosphonic acids in the presence of alkyltrimethylammonium (CnTMA) surfactants. In the aqueous system, mesostructured AOP-2 with short-range orderings was obtained by using methylene diphosphonic acid. Low-temperature calcination at 400 °C of the mesostructured AOP-2 led to the deformation of the mesostructures. In the ethanol−water system, highly ordered mesostructured AOP-2 can be prepared through the reaction of aluminum chloride and alkylene diphosphonic acids. The preparation of ordered mesoporous AOPs with methylene and ethylene groups was achieved by using the method to remove surfactant molecules by calcination at 400 °C. Mesoporous AOPs containing propylene groups cannot be obtained through a similar synthetic procedure containing the low-temperature calcination process. Thermal stabilities of the organic groups within the frameworks are significant for the formation of mesoporous phases. Also, the presence of the organic groups within the frameworks plays an important role in avoiding the deformation of the ordered mesostructures during calcination. The mesoporous AOP-2 having extremely hydrophilic surfaces is quite applicable for the removal of harmful organic compounds such as aldehydes.