scholarly journals Effect of Oxide Supports on the Activity of Pd Based Catalysts for Furfural Hydrogenation

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 837 ◽  
Author(s):  
Mi Yeon Byun ◽  
Dae-Won Park ◽  
Man Sig Lee
Keyword(s):  
Chemical Reduction ◽  
Nucleation And Growth ◽  
Pd Catalyst ◽  
Optimal Conditions ◽  
Reaction Parameters ◽  
Pd Catalysts ◽  
Oxide Supports ◽  
Tio2 Catalyst ◽  
Pd Dispersion ◽  
Furfural Hydrogenation

We investigated the effect of oxide supports on the hydrogenation of furfural over Pd catalysts on various supports (Al2O3, SiO2, TiO2, CeO2, and ZrO2). Pd catalysts (5 wt%) prepared by chemical reduction on various supports. The dispersion and uniformity of Pd were affected by the properties of the support and by the nucleation and growth of Pd. The conversion of furfural was enhanced by greater Pd dispersion. The selectivity for cyclopentanone and tetrahydrofurfuryl alcohol was affected by physicochemical properties of Pd catalyst and reaction parameters. High Pd dispersion and high acidity of the catalyst led to greater C=C hydrogenation, thereby, generating more tetrahydrofurfuryl alcohol. The Pd/TiO2 catalyst showed the highest cyclopentanone yield than other catalysts. The Pd/TiO2 catalyst exhibited the >99% furfural conversion, 55.6% cyclopentanone selectivity, and 55.5% cyclopentanone yield under the optimal conditions; 20 bar of H2, at 170 °C for 4 h with 0.1 g of catalyst.

Furfural hydrogenation over amorphous alloy catalysts prepared by different reducing agents

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 8755-8774
Author(s):  
Haijun Guo ◽  
Hairong Zhang ◽  
Weichao Tang ◽  
Can Wang ◽  
Chao Huang ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
Active Sites ◽  
Chemical Reduction ◽  
Surface Concentration ◽  
Reducing Agents ◽  
Chemical Reduction Method ◽  
Transfer Capability ◽  
Furfural Hydrogenation ◽  
Adsorption Desorption ◽  
Alloy Catalysts

The catalytic hydrogenation of furfural was studied over a series of Ni-B, Co-B, and Ni-Co-B amorphous alloy catalysts that were prepared by the chemical reduction method using KBH4 and NaBH4 as reducing agents. These catalysts were characterized by N2 adsorption/desorption, XRD, XPS, FE-SEM, and TEM. The results showed that NaBH4 had a much stronger reduction ability to enhance the surface concentration of the metallic active sites for furfural hydrogenation and electron transfer capability, leading to much higher hydrogenation activity. In the Ni-Co-B amorphous alloy catalyst, the equilibrium between the isolated Ni-B/Co-B active sites and the combined Ni-Co-B active sites was important in regulating furfural conversion and products distribution.

Carboxyl-containing microporous organic nanotube networks as a platform for Pd catalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 39933-39939 ◽  
Author(s):  
Yang Xu ◽  
Tianqi Wang ◽  
Zidong He ◽  
Aiqing Zhong ◽  
Kun Huang
Keyword(s):  
High Activity ◽  
Catalyst Support ◽  
Pd Catalyst ◽  
Pd Catalysts ◽  
Novel Method ◽  
First Time

A novel method that enables carboxyl-containing microporous organic nanotube networks as a Pd catalyst support (Pd@MONNs) with high activity and stability for the Suzuki–Miyaura reaction is reported for the first time.

Effects of Reaction Parameters on the Growth and Optical Properties of PbSe Nanocrystals

2015 ◽  
Vol 34 ◽  
pp. 79-89
Author(s):  
Immaculate L.A. Ouma ◽  
Paul Mushonga ◽  
Martin O. Onani
Keyword(s):  
Optical Properties ◽  
Structural Properties ◽  
Lead Acetate ◽  
Lead Oxide ◽  
Nucleation And Growth ◽  
Growth Phases ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
Lead Source ◽  
Shape And Size

Colloidal syntheses of PbSe nanocrystals (NCs) have been widely investigated and the properties of nanocrystals have been shown to vary with reaction conditions, time, concentration and chemistry of reagents as well as the surfactants used. In this work the effects of reaction temperature, solvents, ligand purity, lead and selenium sources on the optical and structural properties of PbSe nanocrystals were investigated. PbSe NCs synthesized at 90 °C were observed to be spherical and had a narrower size distribution as compared to those synthesized at higher temperatures. 1-octadecene, trioctylphosphine and oleylamine were investigated as solvents for NC synthesis with the non-coordinating solvent octadecene showing the fastest growth rate with medium sized NCs. The coordinating solvents trioctylphosphine and oleylamine produced larger and smaller NCs respectively; this could be attributed to solvent interference during NC nucleation and growth phases. Oleate ligands were used during these syntheses and the ligand purity was not observed to have a significant effect on the NC optical and structural properties. The selenium precursor used affected the NC size and their optical properties while the lead source influenced both the NC shape and size. Lead acetate produced cubic NCs which were larger than the spherical NCs obtained when lead oxide was used.

Preparation and Characteristics of a New Anion Exchange Resin from Agricultural by-Products, Cassava (Manihot esculenta) Stalk

2013 ◽  
Vol 295-298 ◽  
pp. 87-90
Author(s):  
Wei Ming Mo ◽  
Wang Li ◽  
Cai Yan Kang ◽  
Min Jun Zhang ◽  
Yu Long Lun ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Nitrate Removal ◽  
Influential Factor ◽  
Optimal Conditions ◽  
Reaction Parameters ◽  
Key Factor ◽  
New Type ◽  
By Products

A new type of anion exchange resin was prepared from cassava stalk (CS) after reaction with epichlorohydrin and dimethylamine in the presence of pyridine and N,N-dimethylformamide. In order to obtain the optimal conditions for the preparation of cassava stalk anion exchanger (CS-AE), the single influential factor experiments were carried out, with nitrate removal efficiency as indicator. Factors like dosage of CS and catalyst, experimental temperatures were examined. The results indicated that the optimal synthesis reaction parameters of dosages were CS: pyridine: dimethylamine = 2 g: 30 ml: 35 ml. The optimal experimental temperature was 100 °C; the catalytic temperature was a key factor in the preparation of CS-AE.

Optimized Enzymatic Production of Waste Oil to Biodiesel

2013 ◽  
Vol 291-294 ◽  
pp. 284-289
Author(s):  
Xue Lin Zhang ◽  
Jun Jun Li ◽  
Xiang Hua Tang ◽  
Zhen Rong Xie ◽  
Zun Xi Huang
Keyword(s):  
Response Surface Methodology ◽  
Experimental Designs ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Optimal Conditions ◽  
Optimum Conditions ◽  
Waste Oil ◽  
Reaction Parameters ◽  
Enzymatic Production ◽  
Oil Water

This study employed statistically based on experimental designs to optimize transesterification conditions for biodiesel production from waste oil via lipase-catalyzed in homoeothermy. Optimization of different reaction parameters were done by using response surface methodology. Results indicated optimum conditions including: alcohol to oil molar ratio 3:1, lipase concentration 58.38 U each gram of oil, water and n-hexane content were 24.59% and 13.28% respectively, reaction temperature at 20 °C , and reaction time for 24 h. Under these optimal conditions, 98.24% yield of biodiesel was obtained. This study will probably contribute to the development of continuous enzymatic processes, and maybe a suitable method for industrial production of biodiesel.

Electron Tunneling Induced Periodic Nucleation and Growth of Nanoparticles: Physical Basis of Chemical Reduction

2011 ◽  
Vol 11 (9) ◽  
pp. 3707-3712 ◽  
Author(s):  
Feng Chen ◽  
Hongjun You ◽  
Shengchun Yang ◽  
Zhimao Yang ◽  
Xiaoping Song ◽  
...  
Keyword(s):  
Electron Tunneling ◽  
Chemical Reduction ◽  
Nucleation And Growth ◽  
Physical Basis

The Effect of Physicochemical Treatment on Pd Dispersion of Carbon-Supported Pd Catalysts

2008 ◽  
Vol 135 ◽  
pp. 57-60
Author(s):  
Yong Tae Kim ◽  
Eun Duck Park ◽  
Min Kang ◽  
Jae Eui Yie
Keyword(s):  
Palladium Catalysts ◽  
Activated Carbons ◽  
Palladium Chloride ◽  
Impregnation Method ◽  
Reduction Temperature ◽  
Surface Oxygen ◽  
Carbon Supports ◽  
High Concentration ◽  
Pd Catalysts ◽  
Pd Dispersion

Carbon-supported palladium catalysts were prepared by an impregnation method using palladium chloride and different carbon supports such as activated carbons with different surface oxygen concentrations and a mesoporous carbon, CMK-5.. The different degree of surface oxidation was achieved by the nitric acid and high-temperature heat treatment. The molecular PdCl2 species was stabilized by adding an HCl in an impregnation step.. As the reduction temperature increased, the Pd dispersion decreased for all Pd catalysts. There was no noticeable difference in Pd dispersion among Pd catalysts supported on carbon supports with different physicochemical properties when the reduction temperature was 423 K. Pd catalysts supported on the carbon support with a high concentration of surface oxygen groups showed a better dispersion than did other Pd catalysts when they were reduced at 573 K. The maximum Pd dispersion was observed over Pd catalyst supported on carbon supports with the highest surface area when the reduction temperature was higher than 573 K.

scholarly journals Active sites and mechanisms for H2O2 decomposition over Pd catalysts

2016 ◽  
Vol 113 (14) ◽  
pp. E1973-E1982 ◽  
Author(s):  
Anthony Plauck ◽  
Eric E. Stangland ◽  
James A. Dumesic ◽  
Manos Mavrikakis
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Mean Field ◽  
Pd Catalyst ◽  
Pd Catalysts ◽  
H2o2 Decomposition ◽  
Bond Scission ◽  
Flow Through ◽  
Key Aspects ◽  
Supported Pd

A combination of periodic, self-consistent density functional theory (DFT-GGA-PW91) calculations, reaction kinetics experiments on a SiO2-supported Pd catalyst, and mean-field microkinetic modeling are used to probe key aspects of H2O2 decomposition on Pd in the absence of cofeeding H2. We conclude that both Pd(111) and OH-partially covered Pd(100) surfaces represent the nature of the active site for H2O2 decomposition on the supported Pd catalyst reasonably well. Furthermore, all reaction flux in the closed catalytic cycle is predicted to flow through an O–O bond scission step in either H2O2 or OOH, followed by rapid H-transfer steps to produce the H2O and O2 products. The barrier for O–O bond scission is sensitive to Pd surface structure and is concluded to be the central parameter governing H2O2 decomposition activity.

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