A SOLID-STATE NMR-STUDY OF THE MOLECULAR-SIEVE VPI-5 SYNTHESIZED IN THE PRESENCE OF A CTABR SURFACTANT

Silicon-free and silicon-rich large-pore aluminophospate VPI-5, synthe sized with various contents of AlPO-H3 impurity, was studied by Bloch decay (BD) and cross polarization (CP) NMR under magic angle spinning (MAS). The H-1 --> P-31 CP peaks were considerably stronger from AlPO- H3 than from VPI-5. A detailed examination of the CP kinetics and a ca reful comparison of the CP and BD spectra are prerequisites for the un equivocal interpretation of H-1 --> P-31 CP in porous aluminophosphate s. (C) 1997 Elsevier Science B.V.