Isomerization of n-Hexane over Silica-Supported Heteropoly Acids Promoted by the Reduced Ce–Ni Oxides

Kuang, Wenxing; Rives, Alain; Tayeb, Bouchta Ouled Ben; Fournier, Michel; Hubaut, R.

doi:10.1006/jcis.2001.8169

Cited by 9 publications

(6 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…XRD patterns of fresh and reduced solids are very interesting. For fresh Ni-Ce oxides we observe the XRD patterns of both NiO and CeO 2 compounds but the sample reduced at 498K shows new peaks which can be assigned to Ni 0 while the peaks of the NiO crystal disappear suggesting that most of the nickel oxide has been reduced in metallic species [12]. An identical result is observed with the mixed Pd-Ce oxide: simultaneous presence of PdO and CeO 2 on the fresh oxide and of Pd 0 after reduction at 553K [11].…”

Section: Resultsmentioning

confidence: 88%

“…zeolites [5], sulfated zirconia [6], tungsten/molybdenum oxides [7] and heteropolyacids [8]). In some cases, a third component was added to improve the role of the metallic species [9][10][11][12]. Due to the strong and amenability to "molecular tuning" acidity (through their salts), the heteropolyanions (HPA), which are highly organized systems, are very good candidates for co-catalyze n-alkane isomerization.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanical mixtures of Me (Ni, Pd) Ce oxides and silica-supported heteropolyacids: Role and optimal concentration of each active species in n-hexane isomerization

Hubaut¹,

Tayeb

Kuang

et al. 2006

Kinet Catal

View full text Add to dashboard Cite

-Catalytic properties of silica-supported heteropolyacids (HPA) in a mechanical mixture with reduced Me-Ce oxides (Me=Ni, Pd) in n-hexane isomerization are studied. The role of each component of the mixed oxides (Ce and, typically Ni and Pd) ,and their optimum content were enlightened; cerium, not only is beneficial for eliminating or prevent, the coke deposition but is also effective for maintaining the Keggin structure of the highly-organized HPA during the reaction and, probably allows a better dispersion of the second metal species. Nickel and palladium, present as Ni 0 and Pd 0 reinforce the activation of the alkane which is difficult to obtain by directly attacking by an acid and, thus, enhance noticeably the activity of the catalyst. The best mechanical mixtures are obtained with 30-70 wt % NiCeO-HPW/SiO 2 and 50-50 wt % Pd 0.1 CeO-HPW/SiO 2 .These mixtures have the highest efficiency for a Ni/Ni+W atomic ratio of 0.66 and a Pd/Pd+W ratio of 0.40 respectively. At last the conversion of n-hexane is in the order: HPW>HSiW>HBW which seems consistent with the order of their acid strength as claimed in the literature, but the isomerization selectivity appears slightly higher on HSiW.

show abstract

Section: Resultsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Mechanical mixtures of Me (Ni, Pd) Ce oxides and silica-supported heteropolyacids: Role and optimal concentration of each active species in n-hexane isomerization

Hubaut¹,

Tayeb

Kuang

et al. 2006

Kinet Catal

View full text Add to dashboard Cite

show abstract

“…The catalytic effect was improved with the addition of oxides of transition elements on the CeO 2 surface for n-C 7 asphaltene and resin II decomposition. The good performance of the functionalized nanoparticles is due to the ability of the support to interact with the nanocrystals to produce and promote cracking and isomerization reactions [58]. The Ce-Ni interactions are able to promote the production of the water-gas shift reaction through vacancies of oxygen anions provided by the CeO 2 [20].…”

Section: Thermogravimetric Experimentsmentioning

confidence: 99%

“…Hence, further experiments under isothermal conditions were performed with the functionalized nanoparticles and for different R:A ratios. reactions [58]. The Ce-Ni interactions are able to promote the production of the water-gas shift reaction through vacancies of oxygen anions provided by the CeO2 [20].…”

Section: Thermogravimetric Experimentsmentioning

confidence: 99%

Upgrading of Extra-Heavy Crude Oils by Dispersed Injection of NiO–PdO/CeO2±δ Nanocatalyst-Based Nanofluids in the Steam

et al. 2019

View full text Add to dashboard Cite

The main objective of this study is to evaluate the injection of a dispersed nanocatalyst-based nanofluid in a steam stream for in situ upgrading and oil recovery during a steam injection process. The nanocatalyst was selected through adsorption and thermogravimetric experiments. Two nanoparticles were proposed, ceria nanoparticles (CeO2±δ), with and without functionalization with nickel, and palladium oxides (CeNi0.89Pd1.1). Each one was employed for static tests of adsorption and subsequent decomposition using a model solution composed of n-C7 asphaltenes (A) and resins II (R) separately and for different R:A ratios of 2:8, 1:1, and 8:2. Then, a displacement test consisting of three main stages was successfully developed. At the beginning, steam was injected into the porous media at a temperature of 210 °C, the pore and overburden pressure were fixed at 150 and 800 psi, respectively, and the steam quality was 70%. This was followed by CeNi0.89Pd1.1 dispersed injection in the steam stream. Finally, the treatment was allowed to soak for 12 h, and the steam flooding was carried out again until no more oil production was observed. Among the most relevant results, functionalized nanoparticles achieved higher adsorption of both fractions as well as a lower decomposition temperature. The presence of resins did not affect the amount of asphaltene adsorption over the evaluated materials. The catalytic activity suggests that the increase in resin content promotes a higher conversion in a shorter period of time. Also, for the different steps of the dynamic test, increases of 25% and 42% in oil recovery were obtained for the dispersed injection of the nanofluid in the steam stream and after a soaking time of 12 h, compared with the base curve with only steam injection, respectively. The upgraded crude oil reached an API gravity level of 15.9°, i.e., an increase in 9.0° units in comparison with the untreated extra-heavy crude oil, which represents an increase of 130%. Also, reductions of up to 71% and 85% in the asphaltene content and viscosity were observed.

show abstract

“…When M = W, these compounds are mainly used in acid catalysis, and due to their acidity (stronger than that of sulfuric acid), they can catalyze many reactions, even requiring strong sites such as the isomerization or the cracking of alkanes. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] When M is molybdenum, they are mainly used in oxidation reactions, and here also they can be used for the functionalization of alkanes by peroxides or molecular oxygen. [22][23][24] This classification is very simplistic, and for example the replacement of tungsten by other elements such as noble metals or transition metals should give redox properties to the corresponding product.…”

Section: ' Introductionmentioning

confidence: 99%

Grafting Reaction of Platinum Organometallic Complexes on Silica-Supported or Unsupported Heteropolyacids

et al. 2011

View full text Add to dashboard Cite

Silica-supported Keggin-type heteropolyacids react with platinum(II) complexes displaying a Pt-CH3 group, leading to the evolution of methane and the formation of an organometallic fragment grafted on the polyacid. This species has been characterized by various physicochemical methods such as microanalyses, infrared spectroscopy, solid-state 1D and 2D MAS NMR, and EXAFS. Molecular models were also prepared by reaction of the nonsupported anhydrous polyacid with the platinum(II) methyl complexes. These compounds were characterized in solution by multinuclear NMR (1H, 13C, 183W, and 195Pt) and in the solid state by X-ray diffraction on monocrystals. All data indicate that the interaction between the platinum complex and the polyoxometalate is weak and that this system is better expressed as an organometallic platinum salt of the supported heteropolyacid. This complex can be seen as one of the intermediates in the partial oxidation of methane to methanol, its synthesis being the reverse reaction of the methane activation.

show abstract

Isomerization of n-Hexane over Silica-Supported Heteropoly Acids Promoted by the Reduced Ce–Ni Oxides

Cited by 9 publications

References 46 publications

Mechanical mixtures of Me (Ni, Pd) Ce oxides and silica-supported heteropolyacids: Role and optimal concentration of each active species in n-hexane isomerization

Mechanical mixtures of Me (Ni, Pd) Ce oxides and silica-supported heteropolyacids: Role and optimal concentration of each active species in n-hexane isomerization

Upgrading of Extra-Heavy Crude Oils by Dispersed Injection of NiO–PdO/CeO2±δ Nanocatalyst-Based Nanofluids in the Steam

Grafting Reaction of Platinum Organometallic Complexes on Silica-Supported or Unsupported Heteropolyacids

Contact Info

Product

Resources

About