Direct synthesis and catalytic activity of oxazole derivative copper II complex encapsulated in zeolite from rice husk

Several copper (II) complexes derived from organic ligands [benzo[b]oxazole] acetonitrile]
within the intracrystalline structure of ZSM-5 (Si/Al = 38) through direct
synthesis under autogenous pressure are reported. CuII-
BOA/ZSM-5 complexes
were characterized by elemental analysis, XRD, FT-IR, UV–Vis, DTA/TGA, and
N2
adsorption. XRD patterns of the encapsulated complexes suggest that the zeolite
framework has not collapsed during encapsulation. Until the crystallinity reaches
0.05 CuII-
BOA/Z, the crystallinity rises monotonically, followed by a decrease as
the complex concentration increases. Additionally, the encapsulated copper (II)
complex reduced both its surface area and pore volume relative to the parent zeolite,
suggesting that the CuII-
BOA complex is encapsulated inside it. Among the catalysts
examined, encapsulated-0.05CuII-BOA/Z showed maximum conversion (26%) and
selectivity (90%) toward phenol. Density functional theory (B3LYP-6-31G(d)) was
performed to study the effect of the interaction mode of complex with zeolite. The
NLOs manners were elucidated via 1st and 2nd hyper polarizabilities. The charge
transport mechanism was anticipated using ionization potential (IP) and bond dissociation
enthalpy (BDE), which were subsequently employed to examine the autoxidation
characteristics.