SI-29 MAS NMR-STUDIES OF A HIGH-SILICA FORM OF THE NOVEL MOLECULAR-SIEVE - MCM-22

MCM-22 is a new molecular sieve that contains unique structural featur es. Si-29 MAS NMR studies of a highly siliceous MCM-22 prepared by the hydrothermal treatment of a [B]MCM-22 are presented and discussed in light of the proposed framework topology. The structural information o btained from this NMR investigation is complementary to and consistent with the structure proposed from X-ray diffraction measurements. The major conclusions of this present work are that MCM-22 contains at lea st one buried T-site in its framework structure that is not accessible to a channel wall and that the NMR data favor the orthorhombic form o f the proposed structure.