Study on immobilization of olefin metathesis catalyst on the nanoporous hybrid frameworks (NHFs)

Abstract

Nanoporous hybrid frameworks (NHFs) membrane anchored a Grubbs catalyst was synthesized by reacting between modified NHFs membrane and the catalyst. NHFs membrane was synthesized by blending of urea network sol and silica precursor. The cross-linked network sol was synthesized by polymerizing tetrakis(4-aminophenyl)methane (TAPM) and hexamethylene diisocyanate (HDI). The network membrane was generated via the interplay between phase separation and sol-gel transition. The NHFs membrane was modified by introducing imidazole ring that acted as a ligand of ruthenium olefin metathesis catalyst followed by Grubbs catalyst. The chemical analysis was performed by IR and the morphology was characterized by scanning electron microscope (SEM) and transmittance electron microscope (TEM). The catalytic activity of NHFs membrane anchored ruthenium catalyst was poor in a model reaction. That was considered to be inactivating the catalyst by amine groups present on the NHFs membrane surface. Thus, the amine groups were converted to urea groups by using butyl isocyanate and the catalyst immobilization step was carried out as before. As a result, it was confirmed that the factor for deactivating the catalyst was removed through the improved conversion.