scholarly journals Efficient Synthesis of Methyl Methacrylate by One Step Oxidative Esterification over Zn-Al-Mixed Oxides Supported Gold Nanocatalysts

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 162
Author(s):  
Huayin Li ◽  
Yuan Tan ◽  
Xingkun Chen ◽  
Wenshao Yang ◽  
Chuanqi Huang ◽  
...  
Keyword(s):  
Methyl Methacrylate ◽  
Mixed Oxides ◽  
Gold Catalyst ◽  
Co Adsorption ◽  
Gold Catalysts ◽  
Esterification Reaction ◽  
X Ray ◽  
Oxidative Esterification ◽  
One Step ◽  
Supported Gold

Methyl methacrylate (MMA) is an important monomer in fine chemicals. The synthesis of MMA by one-step oxidative esterification from methacrolein with methanol over a heterogeneous catalyst with high activity, selectivity and stability is highly desirable. Herein, Zn-Al-hydrotalcites (HTs)-supported atomically precise Au25 nanoclusters with different molar ratios of Zn2+/Al3+ were prepared and used as the precursors for this reaction. They exhibited good performances in comparison with the gold catalysts prepared by the deposition precipitation method. The structural and electronic properties were evaluated by various characterization technologies, including X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) of CO adsorption, X-ray photoelectron spectroscopy (XPS), and CO2 temperature-programmed desorption (TPD). The combined characterization results suggested that the adsorption property of gold and the basicity of the catalyst contributes to their high activities. Substrates extended experiments and stability tests implied the potential application of Zn-Al-mixed oxides supported gold catalysts, which paves a new way for supported gold catalyst in the one-step oxidation esterification reaction.

scholarly journals Zn Promoted Mg-Al Mixed Oxides-Supported Gold Nanoclusters for Direct Oxidative Esterification of Aldehyde to Ester

2021 ◽  
Vol 22 (16) ◽  
pp. 8668
Author(s):  
Jie Li ◽  
Shiyi Wang ◽  
Huayin Li ◽  
Yuan Tan ◽  
Yunjie Ding
Keyword(s):  
Photoelectron Spectroscopy ◽  
Mixed Oxides ◽  
Physical Adsorption ◽  
Gold Nanoclusters ◽  
Precipitation Method ◽  
Esterification Reaction ◽  
X Ray ◽  
Oxidative Esterification ◽  
Molar Ratios ◽  
Supported Gold

The synthesis of ester compounds is one of the most important chemical processes. In this work, Zn-Mg-Al mixed oxides with different Zn2+/Mg2+ molar ratios were prepared via co-precipitation method and supported gold nanoclusters to study the direct oxidative esterification of aldehyde and alcohol in the presence of molecular oxygen. Various characterization techniques such as N2-physical adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and CO2 temperature programmed desorption (TPD) were utilized to analyze the structural and electronic properties. Based on the results, the presence of small amounts of Zn2+ ions (~5 wt.%) provoked a remarkable modification of the binary Mg-Al system, which enhanced the interaction between gold with the support and reduced the particle size of gold. For oxidative esterification reaction, the Au25/Zn0.05MgAl-400 catalyst showed the best performance, with the highest turnover frequency (TOF) of 1933 h−1. The active center was believed to be located at the interface between metallic gold with the support, where basic sites contribute a lot to transformation of the substrate.

Hydrogen Interaction with a Ceria−Zirconia Supported Gold Catalyst. Influence of CO Co-adsorption and Pretreatment Conditions

2007 ◽  
Vol 111 (39) ◽  
pp. 14371-14379 ◽  
Author(s):  
Sebastián E. Collins ◽  
José M. Cíes ◽  
Eloy del Río ◽  
Miguel López-Haro ◽  
Susana Trasobares ◽  
...  
Keyword(s):  
Gold Catalyst ◽  
Co Adsorption ◽  
Hydrogen Interaction ◽  
Pretreatment Conditions ◽  
Supported Gold

scholarly journals Morphological analysis of cerium oxide stabilized nanoporous gold catalysts by soft X-ray ASAXS

RSC Advances ◽  
2017 ◽  
Vol 7 (72) ◽  
pp. 45344-45350 ◽  
Author(s):  
C. Rumancev ◽  
A. R. von Gundlach ◽  
S. Baier ◽  
A. Wittstock ◽  
J. Shi ◽  
...  
Keyword(s):  
Cerium Oxide ◽  
Morphological Analysis ◽  
Morphological Changes ◽  
Gold Catalyst ◽  
Gold Catalysts ◽  
Nanoporous Gold ◽  
Morphological Properties ◽  
X Ray ◽  
Stabilizing Effect

Soft X-ray SAXS and ASAXS reveal nanostructural properties and temperature induced morphological changes in catalyst materials. The stabilizing effect of cerium oxide deposits on the gold catalyst and the morphological properties of the cerium oxide were determined.

Carbon-Supported Gold Catalyst Modified by Doping with Ag for Cyclohexene Oxidation

2011 ◽  
Vol 236-238 ◽  
pp. 3046-3050
Author(s):  
Zhen Yu Cai ◽  
Ming Qiao Zhu ◽  
Yue Tang ◽  
Yi Liu ◽  
Huan Dai ◽  
...  
Keyword(s):  
Gold Catalyst ◽  
Catalytic Performance ◽  
Cyclohexene Oxide ◽  
Cyclohexene Oxidation ◽  
X Ray Diffraction ◽  
Efficient Catalyst ◽  
X Ray ◽  
Supported Gold Catalysts ◽  
Transmission Electron ◽  
Supported Gold

Carbon-supported gold catalysts Au/C were prepared by an impregnation-reduction method and modified by AgNO3to obtain bi-metallic catalysts Au-Ag/C, which were characterized by X-ray-diffraction (XRD) and Transmission Electron Microscope (TEM). Their catalytic performance was tested in the oxidation of cyclohexene in an autoclave without any solvent. The results showed that Ag doping can significantly enhance the catalytic performance of carbon-supported gold catalyst. Au(1.0 wt.%)-Ag(1.0 wt.%)/C has been found to be an efficient catalyst for the cyclohexene oxidation with a conversion of 27.6% at 80 °C and 0.4 MPa for 12 h while selectivity for ∑C6products (including cyclohexene oxide, 2-cyclohexene-1-ol, 2-cyclohexene-1-one and cyclohexane-1,2-diol) exceeding 88.9%, especially the selectivity of cyclohexane-1,2-diol up to 47.6%. Moreover, the effects of Au, Ag content on catalytic performance were also reported.

scholarly journals Tuning the selectivity of a supported gold catalyst in solvent- and radical initiator-free aerobic oxidation of cyclohexene

2014 ◽  
Vol 4 (3) ◽  
pp. 752-757 ◽  
Author(s):  
Daniil S. Ovoshchnikov ◽  
Baira G. Donoeva ◽  
Bryce E. Williamson ◽  
Vladimir B. Golovko
Keyword(s):  
Aerobic Oxidation ◽  
Gold Catalyst ◽  
Gold Catalysts ◽  
Radical Initiator ◽  
Supported Gold Catalysts ◽  
Supported Gold

The selectivity of supported gold catalysts in solvent- and radical initiator-free aerobic oxidation of cyclohexene was tuned by either WO3 or MIL-101.

The influence of a hydrophobic carrier, reactant and product during H2O adsorption on Pd surface for the oxidative esterification of methacrolein to methyl methacrylate

2018 ◽  
Vol 20 (15) ◽  
pp. 9965-9974 ◽  
Author(s):  
Jing Ma ◽  
Xueqing Yang ◽  
Yan Nie ◽  
Baohe Wang
Keyword(s):  
Methyl Methacrylate ◽  
Model Reaction ◽  
Oxidative Esterification ◽  
One Step ◽  
The One

Taking the one-step oxidative esterification of MAL to MMA as a model reaction, the effects of the hydrophobic carrier SDB copolymer, the reactant CH3OH and the product MMA during the adsorption of H2O on a Pd surface were investigated.

Recent Progress in Chemical Characterization of Supported Gold Catalysts: CO Adsorption on Au/Ceria–Zirconia

2011 ◽  
Vol 40 (11) ◽  
pp. 1210-1216 ◽  
Author(s):  
Juan J. Delgado ◽  
José M. Cíes ◽  
Miguel López-Haro ◽  
Eloy del Río ◽  
José J. Calvino ◽  
...  
Keyword(s):  
Recent Progress ◽  
Co Adsorption ◽  
Chemical Characterization ◽  
Gold Catalysts ◽  
Supported Gold Catalysts ◽  
Supported Gold
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