MRE Structure Type Advanced Zeolite ZSM-48

ZSM-48 is a high silica zeolite with orthorhombic or pseudoorthorhombic symmetry whose X-ray powder pattern can be indexed on the basis of a Pmma-orthorhombic cell with a = 14.24 ± 0.03Å, b = 20.14 ± 0.04Å, and c =8.40 ± 0.02Å (HZSM-48, = 580). All reflections inconsistent with both C- and l-centering are quite weak suggesting ideal Cmcm or Imma symmetry. ZSM-48 zeolites, owing to narrower pores and lower acidity than ZSM-5, can be useful for direct utilization for toluene methylation. Further, such zeolites with reduced crystal sizes can shorten the pore retention time for small and highly reactive methanol and eliminate diffusion limitations to toluene and p-xylene molecules respectively to avoid methanol overuse in side reactions and to improve catalytic activity for toluene methylation. Envisaging above advantages, nano size ZSM-48 zeolite plays role of its narrow pore, less acidity and small crystals in maximization of p-xylene in toluene methylation reaction.