A hierarchical zeolite-Y hampered metallo-ligand complexes for selective oxidation: A mechanistic point of view

作者:Godhani Dinesh R*; Nakum Haresh D; Parmar Digvijaysinh K; Mehta Jignasu P; Desai Nisheeth C
来源:Microporous and Mesoporous Materials, 2016, 235: 233-245.
DOI:10.1016/j.micromeso.2016.08.016

摘要

A series of Ni2+ and Mn2+ complexes with ligands 1 and 2 derived from the condensation of 1-(2-hydroxyphenyl)ethan-l-one and/or 1-(5-chloro-2-hydroxyphenyl)ethan-1-one with ethane-1,2-diamine have been synthesized as neat and zeolite Y enslaved complexes. The structures of these complexes were established on the basis of various physicochemical (XRD, ICP-AES, elemental analysis, BET, SEM, magnetic measurements, and TGA) and spectroscopic studies (UV-vis and FTIR). The catalytic performance of these hybrid materials was scrutinized for the oxidation of cyclohexene, phenol, styrene, and benzene using 30% H2O2 as an oxidant. Among all catalysts, 3Y ably catalyzed the cyclohexene (100%), phenol (39.2%), styrene (99.3%), and benzene (20.7%) with the higher selectivity of Cyclohex-2-en-1-one (55.6%), catechol (73.2%), benzaldehyde (87.5%), and phenol (80.7%), respectively. It has been revealed that the presence of electron-withdrawing substituents on the aromatic ring of catalyst degrades the catalytic activity and the selectivity of products. The results show that the heterogeneous systems are easily salvaged and reused without substantial fall in the activity and selectivity. Moreover, the involvement of metal hydroperoxide during the catalytic reaction is confirmed by the preparation, characterization, and utilization of metal hydroperoxide of complex 4 as catalyst over phenol oxidation without oxidant.

  • 出版日期2016-11-15