scholarly journals Selective hydrogenation of halogenated arenes using porous manganese oxide (OMS-2) and platinum supported OMS-2 catalysts

2016 ◽  
Vol 188 ◽  
pp. 451-466 ◽  
Author(s):  
Iain J. McManus ◽  
Helen Daly ◽  
Haresh G. Manyar ◽  
S. F. Rebecca Taylor ◽  
Jillian M. Thompson ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Selective Hydrogenation ◽  
Hydrogen Pressure ◽  
Hydrogen Adsorption ◽  
Platinum Group Metal ◽  
Complete Conversion ◽  
Nitrobenzene Hydrogenation ◽  
Rate Of Reaction ◽  
Halogenated Aromatics ◽  
Increasing Temperature

Porous manganese oxide (OMS-2) and platinum supported on OMS-2 catalysts have been shown to facilitate the hydrogenation of the nitro group in chloronitrobenzene to give chloroaniline with no dehalogenation. Complete conversion was obtained within 2 h at 25 °C and, although the rate of reaction increased with increasing temperature up to 100 °C, the selectivity to chloroaniline remained at 99.0%. Use of Pd/OMS-2 or Pt/Al2O3 resulted in significant dechlorination even at 25 °C and 2 bar hydrogen pressure giving a selectivity to chloroaniline of 34.5% and 77.8%, respectively, at complete conversion. This demonstrates the potential of using platinum group metal free catalysts for the selective hydrogenation of halogenated aromatics. Two pathways were observed for the analogous nitrobenzene hydrogenation depending on the catalyst used. The hydrogenation of nitrobenzene was found to follow a direct pathway to aniline and nitrosobenzene over Pd/OMS-2 in contrast to the OMS and Pt/OMS-2 catalysts which resulted in formation of nitrosobenzene, azoxybenzene and azobenzene/hydrazobenzene intermediates before complete conversion to aniline. These results indicate that for Pt/OMS-2 the hydrogenation proceeds predominantly over the support with the metal acting to dissociate hydrogen. In the case of Pd/OMS-2 both the hydrogenation and hydrogen adsorption occur on the metal sites.

scholarly journals Selective hydrogenation of 5-(hydroxymethyl)furfural to 5-methylfurfural over single atomic metals anchored on Nb2O5

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shaopeng Li ◽  
Minghua Dong ◽  
Junjuan Yang ◽  
Xiaomeng Cheng ◽  
Xiaojun Shen ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Function Theory ◽  
Density Function Theory ◽  
Reducing Agent ◽  
Dft Studies ◽  
Complete Conversion ◽  
Hydroxymethyl Furfural ◽  
Metal Atoms ◽  
Direct Hydrogenation ◽  
Reaction Result

Abstract5-Methylfurfural (MF) is a very useful chemical. Selective hydrogenation of biomass platform molecule 5-(hydroxymethyl)furfural (HMF) to MF using H2 as the reducing agent is very attractive, but challenging because hydrogenation of C=O bond in HMF is more favourable than C–OH both kinetically and thermodynamically, and this route has not been realized. In this work, we prepare isolated single atomic catalysts (SACs) Pt1/Nb2O5-Ov, Pd1/Nb2O5-Ov, and Au1/Nb2O5-Ov, in which single metal atoms are supported on oxygen defective Nb2O5 (Nb2O5-Ov). It is discovered that the SACs can efficiently catalyze the hydrogenation of HMF to MF using H2 as the reducing agent with MF selectivity of >99% at complete conversion, while the selectivities of the metal nanocatalysts supported on Nb2O5 are very poor. A combination of experimental and density function theory (DFT) studies show that the unique features of the SACs for the reaction result from the cooperation of the Nb and Pt sites near the interface in the Pt1/Nb2O5-Ov. The Pt atoms are responsible for the activation of H2 and the Nb sites activate C-OH in the reaction. This work opens the way for producing MF by direct hydrogenation of biomass-derived HMF using H2 as the reductant.

H2 Uptake and Synthesis of the Li-dispersed Manganese Oxide Nanotubes

2007 ◽  
Vol 7 (11) ◽  
pp. 4033-4036 ◽  
Author(s):  
Jin Bae Lee ◽  
Soon Chang Lee ◽  
Hae Jin Kim
Keyword(s):  
Electron Microscopy ◽  
Manganese Oxide ◽  
Hydrogen Adsorption ◽  
Gravimetric Method ◽  
Anodic Aluminum Oxide Template ◽  
Outer Diameter ◽  
X Ray Diffraction ◽  
Anodic Aluminum ◽  
Transmission Electron ◽  
Potential Applications

Well aligned Li-dispersed manganese oxide nanotubes were prepared using LiNO3, Mn(NO3)2 · xH2O and an anodic aluminum oxide template by solvent-free method for potential applications in H2 storage. The obtained nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analyses revealed the Mn2O3 nanotubes to have a cubic structure with a uniform length, 40–50 nm in wall thickness and 250 ± 10 nm in the outer diameter. The level of H2 adsorption was determined using the gravimetric method. The Li-dispersed manganese oxide nanotubes showed a 0.26 wt% for the amount of hydrogen adsorption at 77 K under 4.5 MPa.

Selective Hydrogenation of p-Chloronitrobenzene Catalyzed by FexOY@C Supported Pt-Catalyst

2014 ◽  
Vol 960-961 ◽  
pp. 221-224
Author(s):  
Jie Wu ◽  
Guang Yin Fan ◽  
Wen Jun Huang
Keyword(s):  
Reaction Time ◽  
Selective Hydrogenation ◽  
Hydrogen Pressure ◽  
Room Temperature ◽  
Catalytic Properties ◽  
Pt Nanoparticles ◽  
Pt Catalyst ◽  
Water Mixture ◽  
Supported Pt Catalyst

FexOy@C nanocomposites were synthesized and used as carriers for depositing Pt nanoparticles. Catalytic properties of the nanocomposites were investigated for the hydrogenation of p-chloronitrobenzene at room temperature and balloon hydrogen pressure. The catalyst Pt/FexOy@C was extremely active for the hydrogenation of p-chloronitrobenzene. Completely conversion of p-chloronitrobenzene was achieved with a selectivity of 99.7 % in ethanol-water mixture in a reaction time of 40 min. Moreover, it can be reused four times without loss of any activity.

Application of Hydrogen Storage Materials in Hydrogenation of Coal-Derived Preasphaltene

2011 ◽  
Vol 236-238 ◽  
pp. 668-671
Author(s):  
Shi Gang Kang ◽  
Zhi Min Zong ◽  
Heng Fu Shui ◽  
Zhi Cai Wang ◽  
Xian Yong Wei
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Pressure ◽  
Structural Characteristics ◽  
Gas Oil ◽  
Hydrogen Storage Materials ◽  
Reaction Conditions ◽  
Storage Materials ◽  
Heavy Product ◽  
Initial Hydrogen Pressure ◽  
Increasing Temperature

The hydrogenation of preasphaltene (PA), from Chinese Xiaolongtan lignite liquefied heavy product, was investigated with hydrogen storage materials in a batch autoclave. The effects of reaction conditions such as hydrogen storage materials and temperature on the yields of gas+oil, asphaltene, char and the conversions of preasphaltene were discussed. Preliminary studies indicate that increasing temperature not only improves hydrogen donor performance of hydrogen storage materials but also enhances conversion of feedstock PA and gas+oil yield. The conversion of PA and the yield gas+oil get to 72.02% and 41.46%, respectively, under 5% MgH2, 5MPa initial hydrogen pressure, temperature 420°C and reaction time 30min. Meanwhile MgH2 is stronger than NaBH4 in hydrodeoxygenation of PA under the same conditions. Elemental and FTIR analyses were used to illustrate the structural characteristics of feedstock PA and remaining preasphaltene (RPA).

scholarly journals Selective Hydrogenation of Phenol to Cyclohexanol over Ni/CNT in the Absence of External Hydrogen

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 846 ◽  
Author(s):  
Changzhou Chen ◽  
Peng Liu ◽  
Minghao Zhou ◽  
Brajendra K. Sharma ◽  
Jianchun Jiang
Keyword(s):  
Reaction Time ◽  
Physicochemical Properties ◽  
Efficient Method ◽  
Selective Hydrogenation ◽  
Transfer Hydrogenation ◽  
Impregnation Method ◽  
Complete Conversion ◽  
Phenol Derivatives ◽  
Successive Step ◽  
Icp Analysis

Transfer hydrogenation is a novel and efficient method to realize the hydrogenation in different chemical reactions and exploring a simple heterogeneous catalyst with high activity is crucial. Ni/CNT was synthesized through a traditional impregnation method, and the detailed physicochemical properties were performed by means of XRD, TEM, XPS, BET, and ICP analysis. Through the screening of loading amounts, solvents, reaction temperature, and reaction time, 20% Ni/CNT achieves an almost complete conversion of phenol after 60 min at 220 °C in the absence of external hydrogen. Furthermore, the catalytic system is carried out on a variety of phenol derivatives for the generation of corresponding cyclohexanols with good to excellent results. The mechanism suggests that the hydrogenation of phenol to cyclohexanone is the first step, while the hydrogenation of cyclohexanone for the generation of cyclohexanol takes place in a successive step. Moreover, Ni/CNT catalyst can be magnetically recovered and reused in the next test for succeeding four times.

Selective hydrogenation of CO2 and CO to useful light olefins over octahedral molecular sieve manganese oxide supported iron catalysts

2013 ◽  
Vol 132-133 ◽  
pp. 54-61 ◽  
Author(s):  
Boxun Hu ◽  
Samuel Frueh ◽  
Hector F. Garces ◽  
Lichun Zhang ◽  
Mark Aindow ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Selective Hydrogenation ◽  
Molecular Sieve ◽  
Light Olefins ◽  
Iron Catalysts ◽  
Hydrogenation Of Co2 ◽  
Supported Iron

scholarly journals Dependency of Phenol Hydrogenation Activity on Hydrogen Chemisorption over Supported Palladium Catalysts

1997 ◽  
Vol 15 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Nagendranath Mahata ◽  
V. Vishwanathan
Keyword(s):  
Atmospheric Pressure ◽  
Palladium Catalysts ◽  
Hydrogen Adsorption ◽  
Vapour Phase ◽  
Hydrogen Chemisorption ◽  
Hydrogenation Activity ◽  
Phenol Hydrogenation ◽  
Acidic Sites ◽  
Supported Palladium ◽  
Increasing Temperature

A series of catalysts containing 1 wt.% Pd supported on various oxides of commercial origin have been characterised by hydrogen adsorption at 298 K and evaluated for vapour-phase phenol hydrogenation at 473 K employing an H/phenol ratio of 5.4 at atmospheric pressure. The activity of phenol hydrogenation showed a dependence on the irreversible uptake of hydrogen. Among the catalysts studied, Pd/Al2O3 showed a decrease in activity with increasing temperature while Pd/MgO passed through a maximum at 503 K. The Pd/MgO catalysts exhibited a higher dispersion of smaller Pd crystallites leading to higher activity and total selectivity for cyclohexanone. The higher resistance towards deactivation and better stability of the Pd/MgO catalysts suggest that the acidic sites of alumina may be responsible for deactivation, thereby accounting for the lowering of activity with Pd/Al2O3 catalysts.

scholarly journals Ruthenium on Carbonaceous Materials for the Selective Hydrogenation of HMF

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 2007 ◽  
Author(s):  
Stefano Cattaneo ◽  
Hadi Naslhajian ◽  
Ferenc Somodi ◽  
Claudio Evangelisti ◽  
Alberto Villa ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Carbon Nanofibers ◽  
Reaction Temperature ◽  
Selective Hydrogenation ◽  
Liquid Fuel ◽  
Hydrogen Pressure ◽  
Carbonaceous Materials ◽  
Fuel Additives ◽  
Ru Catalysts ◽  
The Stability

We report the use of Ru catalysts supported in the activated carbon (AC) and carbon nanofibers (CNFs) for the selective production of liquid fuel dimethylfuran (DMF) and fuel additives alkoxymethyl furfurals (AMF). Parameters such as the reaction temperature and hydrogen pressure were firstly investigated in order to optimise the synthesis of the desired products. Simply by using a different support, the selectivity of the reaction drastically changed. DMF was produced with AC as support, while a high amount of AMF was produced when CNFs were employed. Moreover, the reusability of the catalysts was tested and deactivation phenomena were identified and properly addressed. Further studies need to be performed in order to optimise the stability of the catalysts.

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