EMM-17, a New Three-Dimensional Zeolite with Unique 11-Ring Channels and Superior Catalytic Isomerization Performance.

A new catalytically active zeolite, designated EMM-17 (ExxonMobil Material-17), with a three-dimensional (3D) 11 × 10 × 10-ring topology has been discovered from high throughput experiments while evaluating a family of new organic structure directing agents (OSDAs), 1-alkyl-4-(pyrrolidin-1-yl)pyridin-1-ium hydroxide. The framework structure was determined by model building techniques and confirmed by diffraction calculations. The EMM-17 structure is a random intergrowth of two polymorphs which have a 3D arrangement of intersecting 11 × 10 × 10-ring pores. EMM-17 is stable to calcination to remove the OSDA and can be reproducibly synthesized in the presence of fluoride using common, inexpensive reagents over a wide Si/Al range from 15 to infinity, enabling the catalyst acidity to be tailored to almost any petrochemical application. Unlike OSDAs for many new zeolite structures, the OSDAs for EMM-17 are prepared in one simple alkylation step, making EMM-17 an easy to prepare, highly accessible, catalytically active zeolite. Zeolites containing odd numbered channel sizes are rare, and this is the first confirmed example of a 3D 11-ring aluminosilicate zeolite with a pore size in between those of the commercially important 10- and 12-ring zeolites such as ZSM-5 and Zeolite-Y, respectively. Catalysts prepared from EMM-17 exhibit significantly higher activity for catalytic isomerization with no loss in selectivity than current state of the art catalysts. Catalytic isomerization of linear to branched alkanes is a critical component of commercial dewaxing, allowing for the improvement of cold flow properties of hydrocarbon fuels and lubricants through selective hydroisomerization of normal paraffins.