The mechanism of cumene peroxidation catalyzed by cobalt(II)‐chelated copolymer

Wang, Cheng Chien; Chen, Hui‐Chun; Chen, Chuh-Yean

doi:10.1002/pat.756

Cited by 3 publications

(3 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Subsequent hydrogen atom abstraction from cumene yields cumene hydroperoxide. The reduction of the hydroperoxide with a Ce III species gives an oxy radical, which is finally converted to 2‐phenyl‐2‐propanol or acetophenone 20. Consistent with this radical mechanism, the Ce‐based aerobic oxidation of cumene was completely quenched by radical traps such as 2,6‐di‐ tert ‐butyl‐4‐methylphenol and (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxy.…”

Section: Resultsmentioning

confidence: 79%

See 1 more Smart Citation

Oxidation of Alkylbenzenes with Cerium Complexes Containing a Tripodal Oxygen Ligand

Wang

et al. 2014

Eur J Inorg Chem

View full text Add to dashboard Cite

The treatment of [Ce(LOEt)2(NO3)2] (LOEt– = [Co(η5‐C5H5){P(O)(OEt)2}3]–) with KMnO4 in water afforded a diamagnetic purple solid 1, which is tentatively formulated as a CeIV permanganate complex, “[Ce(LOEt)2(MnO4)2]”. The ZrIV analogue, [Zr(LOEt)2(MnO4)2] (2), has been prepared similarly from [Zr(LOEt)2(NO3)2] and KMnO4. The recrystallization of 1 from CH2Cl2/hexanes at –18 °C led to the isolation of dinuclear [(CeLOEt)2(μ‐LOEt′)2][MnO4]2 (3), which contains the dianionic tripodal ligand [LOEt′]2– ([(η5‐C5H5)Co{P(O)(OEt)2}2{P(O)2(OEt)}]2–). The reactions of 1 with K[ReO4] and [NH4][OsO3N] afforded the heterodimetallic complexes [Ce(LOEt)2(ReO4)2] (4) and [Ce(LOEt)2(NOsO3)2] (5), respectively. The crystal structures of 3 and 5 have been determined. Freshly prepared 1 can oxidize alkylbenzenes such as toluene, ethylbenzene, and cumene at room temperature to give the corresponding ketone and/or alcohol products. Ce–LOEt complexes are efficient promoters of the aerobic oxidation of alkylbenzenes by a radical mechanism. For example, cumene in the presence of [Ce(LOEt)2(H2O)2]Cl (1 mM) in air at 100 °C for 10 h afforded a ca. 6:1 mixture of 2‐phenyl‐2‐propanol and acetophenone with a total turnover number of 6810.

show abstract

Section: Resultsmentioning

confidence: 79%

“…Ce‐Catalyzed Aerobic Oxidation of Alkylbenzenes: A mixture of Ce complex (1 m M ) in neat alkylbenzene (2.25 mL) was heated at 100 °C in air for 20 h. The yields of the oxidation products were determined by GLC or 1 H NMR spectroscopy20 (for cumene) analysis after reduction with PPh 3 .…”

Section: Methodsmentioning

confidence: 99%

Oxidation of Alkylbenzenes with Cerium Complexes Containing a Tripodal Oxygen Ligand

Wang

et al. 2014

Eur J Inorg Chem

View full text Add to dashboard Cite

show abstract

“…Addition of carboxylic acid did not only increase the overall yield but also influenced the product distribution and hence changed the overall mechanism either directly via the propagation mechanism [54] (Scheme 2, step 2) or via destabilization of the termination product, i.e. the hydroperoxide, in the presence of radicals [60]. Indeed, in the case of pxylene, ethylbenzene and cumene oxidation the hydroperoxide exhibited transient behavior.…”

Section: Discussion and Mechanistic Considerationsmentioning

confidence: 99%

Selective side-chain oxidation of alkyl aromatic compounds catalyzed by cerium modified silver catalysts

Beier

Schimmoeller

Hansen

et al. 2010

Journal of Molecular Catalysis A: Chemical

View full text Add to dashboard Cite

Silver supported on silica effectively catalyzes the aerobic side chain oxidation of alkyl aromatic compounds under solvent-free conditions. Toluene, p-xylene, ethylbenzene and cumene were investigated as model substrates. Typically, the reaction was performed at ambient pressure; only for toluene an elevated pressure was required. Carboxylic acids, such as benzoic acid or p-toluic acid, additionally increased the reaction rate while CeO 2 could act both as a promoter and an inhibitor depending on the substrate and the reaction conditions. Silver catalysts were prepared both by standard impregnation and flame spray pyrolysis. Addition of a Ce precursor to the FSP catalyst resulted in significantly smaller silver particles. Ce-doped FSP catalysts in general exhibited a superior catalytic performance with TONs up to 2000 except for cumene oxidation that appeared to proceed mainly by homogeneous catalysis. In addition, flame-made catalysts were also more stable against silver leaching compared to the impregnated catalysts. The structure of the silver catalysts was studied in detail both by X-ray absorption spectroscopy and transmission electron microscopy suggesting metallic silver to be required for catalytic activity. Catalytic studies point to a radical mechanism which differs depending on the type of substrate.

show abstract

Benzylic oxidation and photooxidation by air in the presence of graphite and cyclohexene

Sereda

Rajpara

2007

Tetrahedron Letters

View full text Add to dashboard Cite

The mechanism of cumene peroxidation catalyzed by cobalt(II)‐chelated copolymer

Cited by 3 publications

References 14 publications

Oxidation of Alkylbenzenes with Cerium Complexes Containing a Tripodal Oxygen Ligand

Oxidation of Alkylbenzenes with Cerium Complexes Containing a Tripodal Oxygen Ligand

Selective side-chain oxidation of alkyl aromatic compounds catalyzed by cerium modified silver catalysts

Benzylic oxidation and photooxidation by air in the presence of graphite and cyclohexene

Contact Info

Product

Resources

About