Synthesis of ZSM-48 zeolites and their catalytic performance: a review

ZSM-48 was first discovered as an impurity phase in the synthesis of ZSM-39. ZSM-48 has a framework based on a ferrierite sheet with non-interpenetrating linear 10-ring channels, the dimensions of which are 5.3 x 5.6 angstrom. ZSM-48 has received extensive attention due to its unique framework structure. In this review, we summarize the synthesis and catalytic performances of ZSM-48 zeolites. In zeolite synthesis, organic cations play a very important role as structure-directing agents or as stabilizing pore fillers. The templating agents for the synthesis of ZSM-48 mainly include tetramethylammonium ions, diamines and hexamethonium ions. Other novel template agents have also been designed to synthesize ZSM-48. Nonaqueous systems and the seed-assisted method are introduced for the synthesis of ZSM-48. EU-1/ZSM-48 co-crystalline zeolites as an interesting zeolite have been synthesized. ZSM-48 also shows excellent performance in shape-selective catalytic reactions because ZSM-48 possesses a unique pore structure. ZSM-48 is mainly applied in cracking, shape-selective, methanol-to-hydrocarbon and hydroisomerization reactions. ZSM-48 showed excellent catalytic performance, especially in hydroisomerization. The hydroisomerization performance of ZSM-48 is further improved through alkali treatment, physical mixing and co-crystalline zeolite formation. The summarized studies reveal the excellent potential for the design and preparation of ZSM-48 with excellent catalytic performance, especially in hydroisomerization reactions.