Synthesis and Characterisation of Aluminophosphate Molecular Sieves

Abstract

A synthesis procedure for the production of aluminophosphate molecular sieves (alpos) has been developed which gives higher yields and an improved product purity, than previous methods. The catalytic activity for methanol conversion to hydrocarbons was used to test for substitution of Si, Co, Fe, Sn, Mg, Zn, Mn, Ge, Mo, W, Ti, Zr, Cr, Ni, Cu or Ca into the AlPO4-5 and AlPO4-11 structures. Substitution of silicon, cobalt, iron and tin were studied in more detail. Proof of framework incorporation involved the use of X-ray diffraction, scanning electron microscopy, temperature-programmed desorption/mass spectrometry, Fourier Transform infrared spectroscopy, nuclear magnetic resonance and Mossbauer spectroscopy. Adsorption of nitrogen, water, carbon dioxide and oxygen was used to investigate the pore volume and the structural properties of AlPO4-5 and AlPO4-11. The problems involved with surface area calculations on the alpos are discussed.