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Copper‐Functionalized Metal–Organic Framework as Catalyst for Oxidant‐Controlled Partial Oxidation of Cyclohexene
Author(s) -
Chotmongkolsap Pannapat,
Bunchuay Thanthapatra,
Klysubun Wantana,
Tantirungrotechai Jonggol
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201701062
Subject(s) - chemistry , cyclohexene , catalysis , cyclohexene oxide , copper , oxidation state , inorganic chemistry , metal organic framework , heterogeneous catalysis , copper oxide , oxide , x ray photoelectron spectroscopy , polymer chemistry , organic chemistry , chemical engineering , adsorption , engineering
Microwave irradiation is exploited for the facile, one‐step functionalization of Cu(acac) 2 to –NH 2 pendant groups of MIL‐53(Al)‐NH 2 , a metal–organic framework material, under mild reaction conditions and a short reaction time. PXRD, XPS, XAS, and EPR spectroscopy are used to investigate the structure and chemical nature of the copper species on the framework. The copper center exists in the +2 oxidation state with a square‐planar geometry and NO 3 coordination environment. The copper complex is anchored to the framework by imine bond formation. This copper‐functionalized MIL‐53(Al)‐NH 2 or MIL‐53[Cu] is employed in the catalytic oxidation of olefins using molecular oxygen (O 2 ) or tert ‐butyl hydroperoxide (TBHP) as the oxidant. The chemoselectivities of the oxidation products depend on the type of oxidant and substrate. When O 2 is used as the oxidant and isobutyraldehyde as the co‐oxidant in the oxidation of cyclohexene with MIL‐53[Cu], cyclohexene oxide is the major product. However, when TBHP is employed as the oxidant, 2‐cyclohexen‐1‐one is the major product. Furthermore, the catalyst can be reused at least three times without a significant loss in activity.