PMo or PW heteropoly acids supported on MCM-41 silica nanoparticles: Characterisation and FT-IR study of the adsorption of 2-butanol

Carriazo, Daniel; Domingo, Concepción; Martı́n, Cristina; Rives, V.

doi:10.1016/j.jssc.2008.05.004

Cited by 49 publications

(20 citation statements)

References 60 publications

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“…6b) shows sharp pyridine absorption peaks at 1,597 and 1,446 cm -1 . This result confirms that pyridine molecules bonded to Lewis acid sites of the catalyst and is in agreement with results previously reported by others [30,32,[36][37][38][39]. Brønsted acid sites are created due to the presence of small clusters of TPA, while the Lewis acid sites might be due to the interaction of dispersed TPA with MCM-41 framework [36,39].…”

Section: Resultssupporting

confidence: 92%

12-Tungstophosphoric acid supported on nano sized MCM-41 as an efficient and reusable solid acid catalyst for the three-component imino Diels–Alder reaction

Abdollahi‐Alibeik

Pouriayevali

2011

Reac Kinet Mech Cat

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One pot three-component imino Diels-Alder reactions of various types of aldehydes, aniline and dihydropyrane were studied in the presence of nano sized MCM-41 supported 12-tungstophosphoric acid (TPA) as solid acid catalyst. MCM-41 as solid support was synthesized in nano size and the catalysts with different loading amounts of TPA (5-30 wt%) were prepared and characterized by XRD, FT-IR and SEM techniques. The results confirm a good dispersion of the heteropoly acid on the solid supports and based on the experimental results, the catalyst with 10 wt% heteropoly acid shows the best catalytic activity using 0.5 mol% heteropoly acid relative to the aldehyde. The recovery experiments show that the catalyst is reusable after calcination without significant loss in its activity.

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Section: Resultssupporting

confidence: 92%

12-Tungstophosphoric acid supported on nano sized MCM-41 as an efficient and reusable solid acid catalyst for the three-component imino Diels–Alder reaction

Abdollahi‐Alibeik

Pouriayevali

2011

Reac Kinet Mech Cat

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“…In the spectrum of Mo/TiAl20, the bands at about 150, 400, 540, 670, and 950 cm −1 , characteristic of anatase, are shown. No bands of the molybdophosphoric anion appearing at 991, 971, 909, 607 and 250 cm −1 [33] are observed in the spectra probably due to the interaction of the anion with the support. The spectrum of CoMo/TiAl20 is nearly identical though the band observed at 150 cm −1 is shifted to 175 cm −1 indicating formation of a bond between cobalt and Ti-OH group.…”

Section: Structure Morphology and Textural Properties Of Samplesmentioning

confidence: 93%

Nanoparticles of TiAlZr mixed oxides as supports of hydrodesulfurization catalysts: Synthesis and characterization

Kraleva

Spojakina

Saladino

et al. 2012

Journal of Alloys and Compounds

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a b s t r a c tTiAlZr mixed oxides, synthesized using sol-gel method, were characterized and used as supports of hydrodesulfurization catalysts (12 wt% Mo) prepared by impregnation either with molybdenum heteropolyacid H 3 PMo 12 O 40 or its cobalt salt Co 1.5 PMo 12 O 40 . Structure, morphology and textural properties of oxides and catalysts were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, Nitrogen adsorption porosimetry, TEM-EDS, temperature-programmed desorption (TPD) and temperature-programmed reduction (TPR) techniques. Activity of the catalytic systems was tested in thiophene hydrodesulfurization (HDS).No formation of a new oxide phase was revealed in the synthesized mixed materials. However the effect of separated oxides on the structure of ternary oxides was observed. Maximum in HDS activity of Mo containing samples was determined by optimum content of alumina in the mixed oxides. Incorporation of cobalt into the heteropolyacid increased the HDS activity about two times and masked the effect of the support composition.

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“…Previously, it had been reported that TSA deposited on MCM-41 forms separate particles on the carrier surface [22]. Assuming that the average surface occupied by one TSA molecule is 1.44 nm 2 , only 120 m 2 /g is covered with the acid in the 40 wt% TSA/MCM-41 catalyst, which is just 12.3% of the total surface of MCM-41.…”

Section: Catalyst Characterisationmentioning

confidence: 99%

Heterogeneously Catalysed Aldol Reactions in Supercritical Carbon Dioxide as Innovative and Non-Flammable Reaction Medium

Musko

Grunwaldt

2011

Top Catal

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Aldol reactions of several aldehydes have been investigated over acidic and basic catalysts in supercritical carbon dioxide at 180 bar and 100°C. Both acidic (Amberlyst-15, tungstosilicic acid (TSA) on SiO 2 and MCM-41) and basic (hydrotalcite) materials showed interesting performance in this preliminary study under the entitled reaction conditions. Small and linear aldehydes, such as propanal, butanal, pentanal and hexanal, react more efficiently than the branched 3-methylbutanal, which is converted much slower. Whereas Amberlyst-15 showed the highest conversion based on the catalyst mass, tungstosilicic acid-based catalysts were significantly better if the rates were related to the number of acidic sites ([1000 h -1 ). The rate depends both on the dispersion and the kind of support. Strikingly, tungstosilicic acid (TSA) on MCM-41 was also an effective catalysts for the selective C=C double bond hydrogenation of 2-butenal and is therefore a potential catalyst for the ''one-pot'' synthesis of 2-ethyl-2-hexenal and 2-ethylhexanal via combined hydrogenation and aldol reaction from 2-butenal. A number of characterisation techniques, such as temperatureprogrammed desorption of ammonia (NH 3 -TPD), transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS), etc. were used to get an insight into the catalyst structure, which support a high dispersion and strong acidity of the tungsten based species on silica and MCM-41.

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PMo or PW heteropoly acids supported on MCM-41 silica nanoparticles: Characterisation and FT-IR study of the adsorption of 2-butanol

Cited by 49 publications

References 60 publications

12-Tungstophosphoric acid supported on nano sized MCM-41 as an efficient and reusable solid acid catalyst for the three-component imino Diels–Alder reaction

12-Tungstophosphoric acid supported on nano sized MCM-41 as an efficient and reusable solid acid catalyst for the three-component imino Diels–Alder reaction

Nanoparticles of TiAlZr mixed oxides as supports of hydrodesulfurization catalysts: Synthesis and characterization

Heterogeneously Catalysed Aldol Reactions in Supercritical Carbon Dioxide as Innovative and Non-Flammable Reaction Medium

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