Synthesis, characterization, and catalytic application of mesoporous SAPO-34 (MESO-SAPO-34) molecular sieves

摘要

A systematic approach was followed for the synthesis of mesoporous silicoaluminophosphate (MESO-SAPO-34) from the preformed microporous SAPO-34 precursors. Mesoporosity of MESO-SAPO-34 was confirmed from powder XRD, nitrogen sorption analysis, and TEM images. The presence of SAPO-34 lattice secondary building unit (SBU) was evident from FTIR spectra. N2 sorption analysis showed type-lV isotherm along with sharp intake at p/p0 below 0.1, confirming the presence of surface microporosities. ~(27)A1 MAS NMR spectra of calcined MESO-SAPO-34 observed three major signals around 0, 34, and 60 ppm corresponding to aluminium species in different coordination environments. The FTIR pyridine adsorption studies on MESO-SAPO-34 revealed the presence of strong Bransted acid sites and thus proved it to be a promising catalyst for liquid-phase synthesis of phenoxy propanol using phenol and propylene oxide.