Amino-TEMPO Grafted on Magnetic Multi-Walled Nanotubes: An Efficient and Recyclable Heterogeneous Oxidation Catalyst

2018 ◽  
Vol 2019 (6) ◽  
pp. 1405-1412 ◽  
Author(s):  
Cristian Gambarotti ◽  
Hans-René Bjørsvik
2007 ◽  
Vol 46 (12) ◽  
pp. 4221-4225 ◽  
Author(s):  
Leon G. A. van de Water ◽  
Shaun Bulcock ◽  
Anthony F. Masters ◽  
Thomas Maschmeyer

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1136 ◽  
Author(s):  
Mufsir Kuniyil ◽  
J. V. Shanmukha Kumar ◽  
Syed Farooq Adil ◽  
Mohamed E. Assal ◽  
Mohammed Rafi Shaik ◽  
...  

In recent years, the development of green mechanochemical processes for the synthesis of new catalysts with higher catalytic efficacy and selectivity has received manifest interest. In continuation of our previous study, in which graphene oxide (GRO) and highly reduced graphene oxide (HRG) based nanocomposites were prepared and assessed, herein, we have explored a facile and solvent-less mechanochemical approach for the synthesis of N-doped graphene (NDG)/mixed metal oxide (MnCO3–ZrO2) ((X%)NDG/MnCO3–ZrO2), as the (X%)NDG/MnCO3–ZrO2 nano-composite was synthesized using physical grinding of separately synthesized NDG and pre-calcined (300 °C) MnCO3–ZrO2 via green milling method. The structures of the prepared materials were characterized in detail using X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Analysis (EDX), Fourier-transform infrared spectroscopy (FTIR), Raman, Thermogravimetric analysis (TGA), and N2 adsorption-desorption isotherm analysis. Besides, the obtained nanocomposites were employed as heterogeneous oxidation catalyst for the alcohol oxidation using green oxidant O2 without involving any surfactants or bases. The reaction factors were systematically studied during the oxidation of benzyl alcohol (PhCH2OH) as the model reactant to benzaldehyde (PhCHO). The NDG/MnCO3–ZrO2 exhibits premium specific activity (66.7 mmol·g−1·h−1) with 100% conversion of PhCH2OH and > 99.9% selectivity to PhCHO after only 6 min. The mechanochemically prepared NDG based nanocomposite exhibited notable improvement in the catalytic efficacy as well as the surface area compared to the pristine MnCO3–ZrO2. Under the optimal circumstances, the NDG/MnCO3–ZrO2 catalyst could selectively catalyze the aerobic oxidation of a broad array of alcohols to carbonyls with full convertibility without over-oxidized side products like acids. The NDG/MnCO3–ZrO2 catalyst were efficiently reused for six subsequent recycling reactions with a marginal decline in performance and selectivity.


Materials ◽  
2018 ◽  
Vol 11 (2) ◽  
pp. 178 ◽  
Author(s):  
Rong Wan ◽  
Qiaofei Xu ◽  
Pengtao Ma ◽  
Chao Zhang ◽  
Jingyang Niu ◽  
...  

1981 ◽  
Vol 46 (11) ◽  
pp. 2657-2662
Author(s):  
Zdeněk Prokop ◽  
Karel Setínek

Some additional data about properties and applicability of a styrene-divinylbenzene polymer catalyst containing acidic and redox functional groups are reported. It is shown that the catalysts of this type can be prepared reproducibly and exhibit catalytic properties comparable to the properties of noble metal catalysts.


1981 ◽  
Vol 46 (5) ◽  
pp. 1237-1247
Author(s):  
Zdeněk Prokop ◽  
Karel Setínek

The catalyst containing redox sites in addition to acid functional groups was prepared by sulphonation of a macroporous chloromethylated styrene-divinylbenzene copolymer with concentrated sulphuric acid at elevated temperatures. Its activity was tested for the oxidation of 2-propanol by molecular oxygen at 120 °C and was found to be comparable to that of the iridium on carbon catalyst.Neutralisation of acid functional groups by alkali metal led to proportional decrease in the oxidation activity. The results of EPR spectroscopic study of these catalysts show that the redox properties of the polymer are caused by carbon clusters which are capable of electron exchange.


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