The relationship between the pore architecture of MFI zeolites and isoamylene oligomerization

Abstract

The application of the traditional MFI zeolite in isoamylene oligomerization is a challenge due to its 10-ring confined channels. In this work, a series of nano-aggregated MFI zeolites are synthesized by using tetrapropyl ammonium (TPA) as the organic structure-directing agent. On the macro level, XRD, FT-IR, and SEM techniques are used to confirm the epitaxial growth process of the agglomerated structure. On the micro level, the weaker guiding effect of TPA on the T_(c) site has been demonstrated through DFT calculation and the ssNMR technique. The samples exhibit excellent catalytic performance, while the dimerization selectivity and yield are more correlated with the pore architecture. Furthermore, the synergy of tetrapropyl ammonium and amphiphilic organosilane optimizes the mesoporosity and acidity effectively, which makes the conversion rate and yield exceed 92.3% and 60% within 12 h, respectively. The conclusions provide a reference for the crystal growth and related application of MFI zeolites.