Direct aerobic liquid phase epoxidation of propylene catalyzed by Mn(iii) porphyrin under mild conditions: evidence for the existence of both peroxide and Mn(iv)-oxo species from in situ characterizations

RSC Advances ◽  
2015 ◽  
Vol 5 (38) ◽  
pp. 30014-30020 ◽  
Author(s):  
Yang Li ◽  
Xiantai Zhou ◽  
Shaoyun Chen ◽  
Rongchang Luo ◽  
Jun Jiang ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Selective Oxidation ◽  
Epoxidation Of Propylene ◽  
Mild Conditions ◽  
Excellent Activity ◽  
Liquid Phase Epoxidation

Manganese(iii) porphyrin exhibited excellent activity for the selective oxidation of propylene. Experimental evidences that the generation of peroxide and Mn(iv) oxo species, which was well confirmed by in situ IR, in situ UV and MS.

Unravelling the radical transition during the carbon-catalyzed oxidation of cyclohexane by in situ electron paramagnetic resonance in the liquid phase

2017 ◽  
Vol 7 (19) ◽  
pp. 4431-4436 ◽  
Author(s):  
Xixian Yang ◽  
Yonghai Cao ◽  
Hao Yu ◽  
Hongyu Huang ◽  
Hongjuan Wang ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Liquid Phase ◽  
Selective Oxidation ◽  
Chemical Industry ◽  
Paramagnetic Resonance ◽  
Oxidation Of Hydrocarbons ◽  
Electron Paramagnetic ◽  
Catalyzed Oxidation

The selective oxidation of hydrocarbons is of great importance in the chemical industry.

Baeyer-Villiger oxidation of ketones catalyzed by iron(III) meso-tetraphenylporphyrin chloride in the presence of molecular oxygen

2008 ◽  
Vol 12 (02) ◽  
pp. 94-100 ◽  
Author(s):  
Xian-Tai Zhou ◽  
Hong-Bing Ji ◽  
Qiu-Lan Yuan
Keyword(s):  
Molecular Oxygen ◽  
Selective Oxidation ◽  
Large Scale ◽  
Turnover Number ◽  
Mild Conditions ◽  
Factors Influencing ◽  
Oxidation By Molecular Oxygen ◽  
Excellent Activity ◽  
Plausible Mechanism ◽  
Villiger Oxidation

Efficient selective oxidation of ketones to lactones by molecular oxygen with benzaldehyde as an oxygen acceptor, in the presence of metalloporphyrins, has been reported. Iron(III) meso-tetraphenylporphyrin chloride ( Fe ( TPP ) Cl ) showed excellent activity and selectivity for oxidation of cyclohexanones under mild conditions. Moreover, different factors influencing ketones oxidation, e.g. catalyst, solvent, temperature and additive, have been investigated. The turnover number (TON) of the Fe ( TPP ) Cl catalyst could reach up to 71000 in a large scale oxidation of cyclohexanone. A plausible mechanism of ketone oxidation by molecular oxygen in the presence of metalloporphyrins and benzaldehyde was proposed.

scholarly journals Influence of Impurities in a Methanol Solvent on the Epoxidation of Propylene with Hydrogen Peroxide over Titanium Silicalite-1

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 15 ◽  
Author(s):  
Gang Wang ◽  
Yue Li ◽  
Quanren Zhu ◽  
Gang Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Liquid Phase ◽  
Competitive Adsorption ◽  
Batch Reactor ◽  
Spectroscopic Studies ◽  
Titanium Silicalite ◽  
Trace Impurities ◽  
Epoxidation Of Propylene ◽  
Liquid Phase Epoxidation

The recycled methanol solvent of the HPPO (liquid-phase epoxidation of propylene and hydrogen peroxide to propylene oxide) process usually contains many kinds of trace impurities, such as fusel alcohol, aldehyde, ketone, ester, acetal, and amine. In this study, the influence of these impurities on the catalytic performance of titanium silicalite-1 (TS-1) in the liquid-phase epoxidation of propylene with H2O2 was investigated with a batch reactor and simulated methanol solvents. The results show that amine and acetone are the most hazardous impurities, as they could remarkably suppress the conversion of H2O2. Furthermore, competitive adsorption experiments and IR and UV-Raman spectroscopic studies indicate that the suppression effect of impurities on the catalytic activity of TS-1 can be attributed to the competitive adsorption of the impurities on the tetra-coordination framework Ti sites. With this funding, the suppression mechanism of different impurities in a methanol solvent on the catalytic activity of TS-1 in the liquid-phase epoxidation of propylene was discussed.

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