Synthesis of aluminophosphate-based layered compounds using Al(OH)3

Abstract

Large novel anionic aluminophosphate-based layered compounds were synthesized using Al(OH)₃ as an aluminum source and cyclohexylamine as an organic template. The characterization studies by means of XRD, SEM. thermal analysis, MAS NMR, FT-IR and elemental analysis showed that cobalt ions were substituted for Al in the tetrahedral framework and that protonated cyclohexylamine cations were intercalated as a double layer form between macroanionic AlPO sheets. The removal of cyclohexylamine by the calcination process resulted in a collapse of the layered structure into an amorphous phase. The empirical formula of the AlPO layered compound was generally 3.4 C₆H₁₂NH₂ [Al₃H₃P₄O₁₆], showing an unusual molar ratio of an Al: P = 0.75 and higher content of organic amines than that of AlPO molecular sieves.