scholarly journals Synthesis of Carboxylic Acid by 2-Hexenal Oxidation Using Gold Catalysts Supported on MnO2

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Hamed Alshammari
Keyword(s):  
Carboxylic Acid ◽  
Preparation Method ◽  
Catalyst Support ◽  
Supported Catalyst ◽  
Size Selectivity ◽  
Pd Catalysts ◽  
Major Pathway ◽  
Components Analysis ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

Synthesis of carboxylic acid can be achieved by the oxidation of aldehyde using air as an oxidant in the presence of a potential catalyst. We demonstrated that 2-hexenal can be oxidized to carboxylic acid by Au, Pd, and Au-Pd catalysts and investigated the effects of catalyst support (graphite, TiO2, MgO, SiC, MnO2, CeO2, and Al2O3), preparation method for supported catalyst (sol immobilization, impregnation, and deposition precipitation), and choice of catalyst components. Analysis of conversion% and selectivity% for 2-hexenoic acid showed that MnO2-supported gold nanoparticles are the best catalysts for 2-hexenal oxidation. Moreover, catalysts prepared by sol immobilization are the most active possibly due to the much smaller gold nanoparticle size. Selectivity for 2-hexenoic acid is a major pathway of oxidation of 2-hexenal.

scholarly journals Application of the Dehydration Homogeneous Liquid–Liquid Extraction (DHLLE) Sample Preparation Method for Fingerprinting of Honey Volatiles

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2277
Author(s):  
Piotr M. Kuś ◽  
Igor Jerković
Keyword(s):  
Carboxylic Acid ◽  
Sample Preparation ◽  
Preparation Method ◽  
Liquid Extraction ◽  
Sample Preparation Method ◽  
Phenyllactic Acid ◽  
Homogeneous Liquid ◽  
Liquid Liquid Extraction ◽  
Wide Range ◽  
Chemical Groups

Recently, we proposed a new sample preparation method involving reduced solvent and sample usage, based on dehydration homogeneous liquid–liquid extraction (DHLLE) for the screening of volatiles and semi-volatiles from honey. In the present research, the method was applied to a wide range of honeys (21 different representative unifloral samples) to determine its suitability for detecting characteristic honey compounds from different chemical classes. GC-FID/MS disclosed 130 compounds from different structural and chemical groups. The DHLLE method allowed the extraction and identification of a wide range of previously reported specific and nonspecific marker compounds belonging to different chemical groups (including monoterpenes, norisoprenoids, benzene derivatives, or nitrogen compounds). For example, DHLLE allowed the detection of cornflower honey chemical markers: 3-oxo-retro-α-ionols, 3,4-dihydro-3-oxoedulan, phenyllactic acid; coffee honey markers: theobromine and caffeine; linden honey markers: 4-isopropenylcyclohexa-1,3-diene-1-carboxylic acid and 4-(2-hydroxy-2-propanyl)cyclohexa-1,3-diene-1-carboxylic acid, as well as furan derivatives from buckwheat honey. The obtained results were comparable with the previously reported data on markers of various honey varieties. Considering the application of much lower volumes of very common reagents, DHLLE may provide economical and ecological advantages as an alternative sample preparation method for routine purposes.

scholarly journals Electrochemical stability of carbon-supported gold nanoparticles in acidic electrolyte during cyclic voltammetry

2016 ◽  
Vol 187 ◽  
pp. 593-604 ◽  
Author(s):  
Jared T. Steven ◽  
Vladimir B. Golovko ◽  
Bernt Johannessen ◽  
Aaron T. Marshall
Keyword(s):  
Gold Nanoparticles ◽  
Cyclic Voltammetry ◽  
Electrochemical Stability ◽  
Acidic Electrolyte ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

Role of Hydroxyl Groups in Low-Temperature CO Catalytic Oxidation over Zn4Si2O7(OH)2 Nanowire-Supported Gold Nanoparticles

2018 ◽  
Vol 122 (44) ◽  
pp. 25456-25466 ◽  
Author(s):  
Jing-Jing Li ◽  
Bao-Lin Zhu ◽  
Gui-Chang Wang ◽  
Zun-Feng Liu ◽  
Wei-Ping Huang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Low Temperature ◽  
Catalytic Oxidation ◽  
Hydroxyl Groups ◽  
Co Catalytic Oxidation ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

Inside Back Cover: Supported Gold Nanoparticles as Reusable Catalysts for Oxidation Reactions of Industrial Significance (ChemCatChem 7/2017)

ChemCatChem ◽  
2017 ◽  
Vol 9 (7) ◽  
pp. 1354-1354
Author(s):  
Luísa Margarida Dias Ribeiro de Sousa Martins ◽  
Sónia Alexandra Correia Carabineiro ◽  
Jiawei Wang ◽  
Bruno Gonçalo Martins Rocha ◽  
Francisco José Maldonado-Hódar ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Oxidation Reactions ◽  
Back Cover ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

ChemInform Abstract: One-Pot Synthesis of Indoles and Aniline Derivatives from Nitroarenes under Hydrogenation Condition with Supported Gold Nanoparticles.

ChemInform ◽  
2010 ◽  
Vol 41 (13) ◽  
Author(s):  
Yoshihiro Yamane ◽  
Xiaohao Liu ◽  
Akiyuki Hamasaki ◽  
Tamao Ishida ◽  
Masatake Haruta ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
One Pot ◽  
Aniline Derivatives ◽  
One Pot Synthesis ◽  
Hydrogenation Condition ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

scholarly journals Probing the Catalytic Efficiency of Supported Heteropoly Acids for Esterification: Effect of Weak Catalyst Support Interactions

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ali Alsalme ◽  
Aliyah A. Alsharif ◽  
Hamda Al-Enizi ◽  
Mujeeb Khan ◽  
Saad G. Alshammari ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Active Sites ◽  
Catalyst Support ◽  
Supported Catalyst ◽  
Catalytic Efficiency ◽  
Biodiesel Production ◽  
Effect Of Temperature ◽  
Heteropoly Acids ◽  
Catalyst Loading ◽  
Esterification Activity

Supported heteropoly acids are an interesting class of solid acid catalysts which possess flexible structure and super acidic properties essentially required for the oil-based biodiesel production. In this study, a series of catalysts containing 25 wt.% of heteropolytungstate (HPW) supported on various clays or SiO2 were prepared, and their catalytic efficiency was evaluated for esterification of acetic acid with heptanol. The as-prepared catalysts were characterized by various techniques including FT-IR spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and BET. The catalytic efficiency of both bulk and supported HPW catalysts for the esterification activity strongly depends on the type of support and amount of catalyst; the bulk HPW catalyst and the catalyst supported by kaolinite with 25 wt.% of HPW exhibited highest activity. In order to study the effect of temperature on conversion, all the catalysts were subjected to different reaction temperatures. It was revealed that esterification activity of both bulk and supported HPW catalysts strongly depends upon the temperature variations of the reaction. Besides, the effect of leaching of active sites on the catalysts performance for biodiesel production was also evaluated by inductively coupled plasma studies (ICP). The kaolinite-supported catalyst (25% HPW/kaolinite) demonstrated higher amount of leaching which is also confirmed by the significant decrease in its catalytic activity when it is used for the second time. However, the higher activity demonstrated by HPW/kaolinite maybe because of some homogeneous reaction indicating a weak catalyst support interaction (WCSI) resulting in the leaching of the catalyst during the test. Furthermore, the effects of other reaction variables such as catalyst loading and reaction time on the conversion of acetic acid were also studied.

Assembly and Interfacial Effects in Hybrid Nanostructures of Zinc Oxide and Gold

2009 ◽  
Vol 1217 ◽  
Author(s):  
Daisuke Ito ◽  
Lallie C McKenzie ◽  
Keiichiro Masuko ◽  
James E Hutchison
Keyword(s):  
Gold Nanoparticles ◽  
Hybrid Structure ◽  
Hybrid Nanostructures ◽  
Organic Ligands ◽  
Zno Films ◽  
Zno Nanowire ◽  
Methanol Vapor ◽  
Supported Gold Nanoparticles ◽  
Supported Gold ◽  
Catalytic Effects

AbstractGold nanoparticles were linked to ZnO films and nanowires using phosphonic and carboxylic acid ligands. TEM and STEM-HAADF characterization showed that gold nanoparticles modified with both types of ligands anchored on ZnO nanowire surfaces as well as on ZnO films. After removing the ligands from the interface between ZnO nanowires and supported gold nanoparticles, the electric conductivity in the presence of methanol vapor increased by 100 times as compared to the bare ZnO nanowire, which suggested enhanced-catalytic effects due to the hybrid structure. In addition, ZnO/Au nanomaterials were synthesized by linking ZnO nanoparticles and carboxylate-functionalized gold nanoparticles in solution. UV-vis characterization showed both the bandgap absorption from ZnO and the plasmon absorption from gold nanoparticles. Formation of hybrid nanosystems like these using organic ligands as linkers not only can lead to materials with enhanced properties but also minimize the waste of precious elements because the assembly process is an additive, rather than subtractive, process.

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