Synthesis of crystalline microporous aluminophosphates using organic sulfonium compounds and multi-ammonium surfactants as structure-directing agents

Abstract

The structure-directing agents play a key role in determining the pore structure of crystalline microporous aluminophosphates (AlPOs), and the organic amine and ammonium molecules have been widely used. In the present thesis, AlPOs were synthesized using multi-ammonium surfactants and organic sulfonium-based compounds as structure-directing agents. In the AlPO synthesis using multi-ammonium surfactants, meso-level morphologies including nanosheet or nanosponge were produced through the self-assembly of surfactant molecules into micelles. At the same time, ATO-type microporous framework was constructed by ammonium functionalities in the head group of surfactant. It was revealed that the organic sulfide molecules can perform structure-directing function for AlPOs by being protonated into sulfoniums in the AlPO synthesis gel, however, final product was a mixture of AFI-type AlPO and non-porous aluminophosphate due to the weak basicity of sulfide molecules. Instead, ATS-type AlPO can be produced in a single phase with extended synthesis domain when using the triphenylsulfonium molecule as a structure-directing agent.