Synthesis, structural configuration and DFT molecular orbital studies of [Mn-2[benzo[b]oxazole] acetonitrile] complexes encapsulated in ZSM-5: Direct synthesis of phenol by benzene hydroxylation
Abstract
n situ synthesis of Mn-BOA [BOA = 2[benzo[b]oxazole] acetonitrile] complexes with loadings from 7.8 to 12.3 wt% in the microporous structure of zeolite ZSM-5 (Si/Al = 38) by the zeolite synthesis method was reported. The structure and characterization of the prepared samples have been identified by elemental analyses, XRD, XPS, EPR, FT-IR, UV-vis, TGA/DTGA, mass spectroscopy and pore structure analysis by nitrogen adsorption at −196 °C. A monotonic increase in crystallinity up to Mn-BOA(10.3%)/Z was shown and hence must be attributed to templating effect of manganese complex. Concurrently, the surface areas and pore volumes were decreased, suggesting that the complex remained intact within the zeolite walls. The XPS analysis of Mn-BOA(9.3%)/Z and Mn-BOA(12.3%)/Z confirm that manganese exists in the +2 oxidation state, though the latter only has a satellite feature around 646 eV which could …