Mordenite nanorods prepared by an inexpensive pyrrolidine-based mesoporogen for alkane hydroisomerization

We report the synthesis of hierarchical mordenite zeolite nanorods in one step using inexpensive mono-quaternary ammonium N-cetyl-N-methylpyrrolidinium (C ₁₆ NMP) as mesoporogen to the synthesis gel. The presence of a small amount of C ₁₆ NMP results in the formation of 0.6–1 μm rods-like crystals oriented along the c-axis with a high mesoporous volume (0.12 cm ³ g ⁻¹ ) and external surface area (∼90 m ² g ⁻¹ ) compared to bulk mordenite. Acidity characterization shows that the presence of C ₁₆ NMP during mordenite formation leads to a redistribution of aluminum in the zeolite framework: the amount of Brønsted acid sites in the side-pockets (8MR channels) is increased at the expense of those in the 12MR main channels. As these latter acid sites are the ones involved in the conversion of alkene intermediates in bifunctional hydroconversion of alkanes, an optimized hierarchical mordenite prepared with C ₁₆ NMP displays a more ideal hydrocracking selectivity than bulk MOR prepared solely with sodium.