Hydrogenation Of Model Compounds Research Articles

Effect of PDADMAC with different molecular weight regulating Hβ Properties on hydrogenation performance of NiMoC/Hβ catalysts

Using different molecular weight of PDADMAC as template, Hβ zeolites and NiMoC/Hβ-Mx catalysts were successfully prepared. The textural properties, acidity and active metal dispersion of samples were characterized by XRD, N2 adsorption and desorption, NH3-TPD, Py-FTIR, H2-TPR, XPS, HRTEM characterizations, to have a better understanding of the importance of PDADMAC molecular weight role. Hydrogenation of model compounds, including naphthalene and quinoline, and real oils were performed on a fixed bed to evaluate the NiMoC/Hβ-Mx catalysts aromatics hydrogenation performance. By analyzing the collected liquid and gas products, it was found that the NMCH-M3 catalyst with PDADMAC molecular weight of 400,000–500,000 exhibited excellent hydrogenation performance in both model compounds and real oils. The mesopore diameter of NiMoC/Hβ-Mx catalysts has great effect on hydrogenation of real oils where the larger pore size is favorable for the hydrogenation reaction. Meanwhile, the B/L ratio of total acid sites and strong acid sites have great effect on aromatics hydrogenation.

Hydrogenation of model compounds in the presence of iron-containing catalysts

A method for the preparation of a composite iron oxide catalyst on a carbon support is described in this work. The hydrogenation of model polyaromatic compounds in the presence of iron-containing catalysts was studied.

Hydrogenation of Model Compounds Catalyzed by MCM-41-Supported Nickel Phosphide

MCM-41 supported nickel phosphide (Ni2P/MCM-41) was prepared by temperature-programmed reduction of the corresponding phosphate. The catalyst activity for hydrodeoxygenation (HDO), hydrodearomatization (HDA), hydrodenitrogenation (HDN) and hydrodesulfurization (HDS) was investigated in a fixed bed reactor. O-cresol HDO, 1-methylnaphthalene HDA, quinoline HDN, dibenzothiophene HDS and simultaneous HDO, HDA, HDN, HDS were respectively tested at different temperatures with constant pressure (6.0 MPa), liquid hourly space velocity (3.0 h-1), hydrogen-to-oil volume ratio (600:1). The results indicate that Ni2P /MCM-41 catalyst has great performance on HDO, HDA, HDN, HDS in single model compound reactions. O-cresol and DBT are almost completely transformed at 375°C, while 1-methylnaphthalene and quinoline reach the highest conversion at 300°C. In the simultaneous reactions, quinoline shows higher conversion by competitive adsorption on the catalyst hydrogenation sites, leading to conversion decrease of o-cresol, 1-methylnaphthalene and DBT.

Application of the Shvo catalyst in homogeneous hydrogenation of bio-oil obtained from pyrolysis of white poplar: New mild upgrading conditions

Upgrading of bio-oils obtained from the fast pyrolysis of biomasses requires the development of efficient catalysts able to work under mild conditions and to cope with the complex chemical nature of the reactant. The present work focuses on the use of the ruthenium based Shvo homogeneous catalyst for the hydrogenation of model mixtures (vanillin, cinnamaldehyde, methylacetophenone, glycolaldehyde, acetol, acetic acid) and of a real bio-oil. The hydrogenation of model compounds has been investigated both in mono- and biphasic mixtures under a P(H2)=10atm in the temperature range of 90–145°C varying the substrate to catalyst molar ratio from 2000:1 to 200:1. Employing the most active reaction conditions (substrate/catalyst 200:1, T=145°C, P(H2)=10atm) the Shvo catalyst maintains its performances under acidic “bio-oil conditions” leading to the almost quantitative conversion of the polar double bonds within 1h. The activity of the Shvo catalyst was also investigated for the hydrogenation of a bio-oil from poplar in solvent free conditions. Hydrogenation deeply changed the chemical nature of the pyrolysis oil. Aldehydes, ketones and non-aromatic double bonds were almost totally hydrogenated. The catalytic system also promoted the hydrolysis of sugar oligomers into monomers.

Hydrodesulfurization and hydrogenation of model compounds on silica–alumina supported bimetallic systems ☆

Silica–alumina supported Pd catalysts with a second metal such as Cu, Ru or Pt have been prepared (nominal content: 1 wt%) and tested in the naphthalene hydrogenation (HYD) and dibenzothiophene hydrodesulfurization (HDS) model reactions. These catalysts were characterized by means of temperature-programmed reduction, NH 3 temperature-programmed desorption and photoelectron spectroscopy techniques. The combined use of all these techniques revealed that only in the case of PtPd system a rather uniform distribution of the metals across the pore network is achieved. Another important observation was that the PtPd system exhibited strong Brönsted acid sites. The highest HYD and HDS activities of the PtPd bimetallic catalyst can be related not only to a high dispersion of the metals and their uniform distribution but also to its strong Brönsted acidity. The PtPd system presented the highest DBT conversion (83.1%) and the highest C–S hydrogenolysis activity as illustrated by the lowest S-containing products (21.9 wt%) as compared with the much higher S-containing products (54.8 wt%) obtained with the monometallic Pd/ASA catalyst under the same experimental conditions.

95/03454 Hydrogenation of model compounds in syngas-D 2O systems

95/03454 Hydrogenation of model compounds in syngas-D 2O systems

Hydrogenation of Model Compounds in Syngas-D2O Systems

Coal model compounds were hydrogenated and desulfurized in the presence of solvent and catalyst by using syngas with steam in place of hydrogen. Nickel molybdate catalyst exhibited good activities for hydrogenation and desulfurization of model compounds at high pressure and elevated temperature with the use of syngas and steam. Extensive water-gas shift conversion also took place simultaneously. Hydrogenation of phenanthrene and dibenzothiophene was carried out in syngas-water systems, and the results were compared with those obtained in H 2 system. The extent of hydrogenation increased with the increase of H 2 /CO mole ratio in syngas. Hydrogen consumed during the hydrogenation was replenished by the accompanying water-gas shift reaction in syngas-H 2 O systems. Hydrodesulfurization of dibenzothiophene carried out in H 2 -C0-D 2 O and D 2 -C0-H 2O systems yielded deuterated products of cyclohexylbenzene and biphenyl in both systems, indicating that both active deuterium produced via water-gas shift reaction of CO with D 2O as well as deuterium in gas phase participated in the hydrodesulfurization along with the hydrogen/deuterium exchange reaction with substrates

The effect of metal distribution across pellets on the activity of nickel–tungsten hydrotreating catalysts

AbstractNickel–tungsten‐based hydrotreating catalysts have been prepared with different metals impregnation profiles and tested for the hydrodesulphurisation, hydrodenitrogenation and hydrogenation of model compounds. Penetration of the catalyst by the model compounds depends on the pore structure of the support and determines activity. Best performance is associated with optimal Ni:W ratios dished across the active region of the catalyst rather than with an even impregnation across all of the support.

Hydrogen transfer in the hydrogenation of model compounds

Dibenzyl and benzyl phenyl ether were reacted together in naphthalene, tetralin and decalin, respectively under hydrogen or nitrogen atmosphere. Stabilized nickel was used as catalyst, and reaction was carried out at 250 °C and at 400 °C. The main reaction was the direct hydrogenation of samples by gaseous hydrogen on the catalyst surface.

Comparative study of alumina- and carbon-supported catalysts for hydrogenolysis and hydrogenation of model compounds and coal-derived liquids

Carbon- and alumina-supported Fe, Mo, Fe-Mo, and Co-Mo sulfide catalysts were compared for their ability to catalyze hydrotreating reactions such as dibenzothiophene hydrodesulfurization, quinoline hydrodenitrogenation, dibenzofuran hydrodeoxygenation, and hydrogenation of butenes, naphthalene, biphenyl, and coal extract. The temperature and pressure varied from 653 to 703 K and from 1 to 300 bar of H,, respectively. Below 50 bar of H, the carbon-supported catalysts were more active for hydrogenolysis and hydrogenation than the aluminasupported ones. However, further H, pressure increase was most effective for the latter catalysts. The activity differences between carbon- and alumina-supported catalysts are ascribed to differences in active phase-support interaction. Generally, iron sulfide was found less active than molybdenum sulfide, and iron sulfide also appeared to be less effective than cobalt sulfide in promoting molybdenum sulfide. However, the Fe-Mo sulfide showed the higher selectivity for hydrogenation relative to hydrodesulfurization. Carboksupported iron sulfide (low-cost catalyst) had considerable activity for coal extract hydrogenation.