Here, we report the synthesis and structure of three high-silica molecular sieves, SSZ-35, SSZ-36, and SSZ-39, that are prepared from a library of 37 different cyclic and polycyclic quaternized amine molecules that are used as structure-directing agents (SDAs). The size and shape of the quaternized amine molecules are purposely designed in order to obtain novel zeolite structures, and the synthesis of these molecules is presented. The selectivity for the three molecular sieve phases is found to depend on both the SDA and the degree of heteroatom lattice substitution of Al3+ or B3+ in the silicate framework. Molecular modeling is utilized to probe the effects of the nonbonded SDA/zeolite-framework interaction energy on the selectivity for the observed molecular sieve phase. The Rietveld refinement of the powder X-ray data confirms the structure of the SSZ-39 zeolite to be isomorphous with the aluminophosphate molecular sieve, SAPO-18 (AEI). The structure of SSZ-36 is found to possess a range of fault probabilities between the two-dimensional channel system, end-member polymorphs, ITQ-3 and RUB-13 (International Zeolite Association Codes ITE and RTH, respectively). The SSZ-35 structure is reported to contain a one-dimensional pore system possessing stacked cages circumscribed by alternating rings of 10 and 18 tetrahedral atoms (10- and 18-membered rings).

The syntheses, structure solutions, and physicochemical and catalytic characterizations of the novel zeolites SSZ-53 and SSZ-59 are described. SSZ-53 and SSZ-59 were synthesized under hydrothermal conditions with the [1-(4-fluorophenyl)cyclopentylmethyl]trimethyl ammonium cation and 1-[1-(4-chlorophenyl)cyclopentylmethyl]-1-methyl azocanium cation, respectively, as structure-directing agents. The framework topology of SSZ-53 was solved with the FOCUS method, and the structure of SSZ-59 was determined by model building. Rietveld refinement of synchrotron X-ray powder diffraction data confirms each proposed model. SSZ-53 and SSZ-59 each possess a one-dimensional channel system delimited by 14-membered rings. Results from transmission electron microscopy, electron diffraction, catalytic experiments (spaciousness index and constraint index tests), and argon and hydrocarbon adsorption experiments are consistent with the proposed structures.

The framework structures of two closely related molecular sieves, SSZ-26 and SSZ-33, are described. These materials possess a previously missing but desired structural feature in a group of industrially significant zeolites. They contain a three-dimensional pore system that provides access to the crystal interior through both 10- and 12-rings. This property is a consequence of the organic structure-directing agents used in the synthesis of these materials. These materials are examples of the purposeful design of a micropore architecture. Both SSZ-26 and SSZ-33 contain the 4=4-1 building unit that had been previously found only in natural zeolites.

We have obtained the direct evidence by high-resolution electron microscopy (HREM) that a pure MEL type zeolite has been successfully synthesized in an all-silica form using a novel organocationic templating agent. It has been also confirmed from a synchrotron X-ray powder diffraction pattern obtained at room temperature that the crystal structure of this all-silica zeolite is of the MEL-type by use of the Rietveld method.