Selective ortho-methylation of phenol with methanol over copper manganese mixed-oxide spinel catalysts

Reddy, A. Siva Rami; Gopinath, Chinnakonda S.; Satyanarayana, C.V.V.

doi:10.1016/j.jcat.2006.07.014

Cited by 104 publications

(59 citation statements)

References 44 publications

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“…As for the valence of Mn species in Figure 3b, only Mn 3 + species can be observed at 642.2 eV in the fresh MnAl and CuMnAl samples. [16,17] After CO pretreatment, the values of the full width at half maximum (FWHM) of the Mn 2p3 = 2 of all the pretreated samples are higher than those of the fresh samples, thus indicating that manganese oxide may exist at more than one oxidation state in CO-pretreated samples. Furthermore, satellite peaks at 645.7 eV as well as 641.5 eV that correspond to Mn 2 + species can be observed, thereby indicating the presence of Mn 3 + !Mn 2 + during the CO-pretreatment process.…”

Section: Resultsmentioning

confidence: 99%

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

et al. 2011

Chemistry A European J

118

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NO reduction by CO was investigated over CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuOMn2O3/γ-Al2O3 model catalysts before and after CO pretreatment at 300 °C. The CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst exhibited higher catalytic activity than did the other catalysts. Based on X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis diffuse reflectance spectroscopy (DRS), Raman, and H2-temperature-programmed reduction (TPR) results, as well as our previous studies, the possible interaction model between dispersed copper and manganese oxide species as well as γ-Al2O3 surface has been proposed. In this model, Cu and Mn ions occupied the octahedral vacant sites of γ-Al2O3, with the capping oxygen on top of the metal ions to keep the charge conservation. For the fresh CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, the -Cu-O-Cu- and -Mn-O-Mn- species were formed on the surface of γ-Al2O3, respectively; but for the fresh CuO-Mn2O3/γ-Al2O3 catalyst, -Cu-O-Mn- species existed on the surface of -Al2O3. After CO pretreatment, -Cu-□-Cu- and -Mn-□-Mn- (□ represents surface oxygen vacancy (SOV)) species would be formed in CO-pretreated CuO/γ-Al2O3 and CO-pretreated Mn2O3/γ-Al2O3 catalysts, respectively; whereas -Cu-□-Mn- species existed in CO-pretreated CuO-Mn2O3/γ-Al2O3. Herein, a new concept, surface synergetic oxygen vacancy (SSOV), which describes the oxygen vacancy formed between the individual Mn and Cu ions, is proposed for CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst. In addition, the role of SSOV has also been approached by NO temperature-programmed desorption (TPD) and in situ FTIR experiments. The FTIR results of competitive adsorption between NO and CO on all the CO-pretreated CuO/γ-Al2O3, Mn2O3/γ-Al2O3, and CuO-Mn2O3/γ-Al2O3 samples demonstrated that NO molecules mainly were adsorbed on Mn2+ and CO mainly on Cu+ sites. The current study suggests that the properties of the SSOVs in CO-pretreated CuO-Mn2O3/γ-Al2O3 catalyst were significantly different to SOVs formed in CO-pretreated CuO/γ-Al2O3 and Mn2O3/γ-Al2O3 catalysts, and the SSOVs played an important role in NO reduction by CO.

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Section: Resultsmentioning

confidence: 99%

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

et al. 2011

Chemistry A European J

118

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“…Two main peaks due to Mn 2p 1/2 and Mn 2p 3/2 were observed. By performing peak-fitting deconvolutions, the Mn 2p 3/2 of mixed-valence manganese system can be divided into three characteristic peaks, which can be attributed to Mn 2+ (640.4 eV), Mn 3+ (642.0 eV), and Mn 4+ (643.2 eV), respectively [35]. The relative concentrations of Mn 4+ was: Mn/CeTi > Mn/CeSn > Mn/CeO 2 .…”

Section: Surface Analysis Of the Catalysts (Xps)mentioning

confidence: 99%

Effect of metal ions doping (M = Ti4+, Sn4+) on the catalytic performance of MnO /CeO2 catalyst for low temperature selective catalytic reduction of NO with NH3

Xiong

Tang

Yao

et al. 2015

Applied Catalysis A: General

200

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“…It is an insulating and normal spinel compound [1][2][3][4][5] and has various catalytic activity such as water gas shift reaction, combustion of halogenated hydrocarbons, alkylation of phenol, dehydrogenation and hydrogenation [6][7][8][9][10][11]. It is also used as ceramic material, heat resistant pigment [12,13], substrate for epitaxial growths [14,15], high density magnetic memory media, etc [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Cobalt Chromite Nanoparticles by Thermolysis of Mixed Cr3+ and Co2+ Chelates of 2-Mercaptopyridin N-Oxide

Edrissi

Keshavarz

2012

Nano-Micro Lett.

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Pure greenish-blue cobalt chromite (CoCr2O4) nanoparticles with narrow particle range of 4.1±1.9 nm and surface area of 78.2 m 2 ·g −1 were synthesized through mixed chelates thermolysis of corresponding metals using 2-Mercaptopyridine N-oxide sodium salt as chelating agent. During the thermolysis procedure, high amount of gases were emitted that led to the formation of nanoparticles with high surface area. The product was characterized by TGA, DTG, XRD, TEM, SEM, LLS, BET and chemical analysis. Design of experiments was performed to fulfill the two levels L4 Taguchi design. It was found that the temperature and time of thermolysis process have significant effect on the particle size reduction. The Oxidation of trichloroethylene was carried out over CoCr2O4 nanocrystallite. Catalytic activity analysis revealed that the synthesis CoCr2O4 possesses high catalytic activity for this process.

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Selective ortho-methylation of phenol with methanol over copper manganese mixed-oxide spinel catalysts

Cited by 104 publications

References 44 publications

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

Effect of metal ions doping (M = Ti4+, Sn4+) on the catalytic performance of MnO /CeO2 catalyst for low temperature selective catalytic reduction of NO with NH3

Synthesis of Cobalt Chromite Nanoparticles by Thermolysis of Mixed Cr3+ and Co2+ Chelates of 2-Mercaptopyridin N-Oxide

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Selective ortho-methylation of phenol with methanol over copper manganese mixed-oxide spinel catalysts

Cited by 104 publications

References 44 publications

The Remarkable Enhancement of CO‐Pretreated CuOMn2O3/γ‐Al2O3 Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

The Remarkable Enhancement of CO‐Pretreated CuOMn2O3/γ‐Al2O3 Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

Effect of metal ions doping (M = Ti4+, Sn4+) on the catalytic performance of MnO /CeO2 catalyst for low temperature selective catalytic reduction of NO with NH3

Synthesis of Cobalt Chromite Nanoparticles by Thermolysis of Mixed Cr3+ and Co2+ Chelates of 2-Mercaptopyridin N-Oxide

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The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy

The Remarkable Enhancement of CO‐Pretreated CuOMn₂O₃/γ‐Al₂O₃ Supported Catalyst for the Reduction of NO with CO: The Formation of Surface Synergetic Oxygen Vacancy