Superacid and Catalytic Properties of Sulfated Zirconia

Chen, Fang Ren; Coudurier, G.; Joly, Jean‐François; Védrine, J.C.

doi:10.1006/jcat.1993.1304

Cited by 319 publications

(144 citation statements)

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“…For the 10 wt% WZ sample, only t-ZrO2 was detectable even after calcination at 700 °C. Tungsten thus serves to stabilise the tetragonal phase with respect to the monoclinic, in accordance with previous reports for sulfated and tungstated zirconia [15,17,18]. Crystallite size for the t-ZrO2 phase in the WZ materials were also far smaller than those of the parent m-ZrO2, varying from 6.6 nm (500 °C) to 9.6 nm (700 °C).…”

Section: Catalyst Characterizationsupporting

confidence: 89%

Valorisation of Vietnamese Rice Straw Waste: Catalytic Aqueous Phase Reforming of Hydrolysate from Steam Explosion to Platform Chemicals

Giang¹,

Osatiashtiani²,

Santos³

et al. 2014

Catalysts

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A family of tungstated zirconia solid acid catalysts were synthesised via wet impregnation and subsequent thermochemical processing for the transformation of glucose to 5-hydroxymethylfurfural (HMF). Acid strength increased with tungsten loading and calcination temperature, associated with stabilisation of tetragonal zirconia. High tungsten dispersions of between 2 and 7 W atoms·nm −2 were obtained in all cases, equating to sub-monolayer coverages. Glucose isomerisation and subsequent dehydration via fructose to HMF increased with W loading and calcination temperature up to 600 °C, indicating that glucose conversion to fructose was favoured over weak Lewis acid and/or base sites associated with the zirconia support, while fructose dehydration and HMF formation was favoured over Brönsted acidic WOx clusters. Aqueous phase reforming of steam exploded rice straw hydrolysate and condensate was explored heterogeneously for the first time over OPEN ACCESSCatalysts 2014, 4 415 a 10 wt% WZ catalyst, resulting in excellent HMF yields as high as 15% under mild reaction conditions.

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Section: Catalyst Characterizationsupporting

confidence: 89%

Valorisation of Vietnamese Rice Straw Waste: Catalytic Aqueous Phase Reforming of Hydrolysate from Steam Explosion to Platform Chemicals

Giang¹,

Osatiashtiani²,

Santos³

et al. 2014

Catalysts

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“…7 The formation of a benzene dimer radical cation, polycondensation products and a biphenyl radical cation has been reported by Timoshok et al 8 in an ESR investigation of benzene adsorbed on sulfated ZrO 2 , after heating at several temperatures. Chen et al 9 also observed the formation of radical species in samples of benzene adsorbed on sulfated ZrO 2 , but only the biphenyl radical cation was observed; they also observed an ESR signal from Zr 3C , formed by reduction of Zr 4C . Other inorganic solids that have very well-known oxidizing abilities are some zeolites 10,11 and some transitionmetal-exchanged clays 12,13 such as montmorillonites with Cu 2C and Fe 3C .…”

Section: Introductionmentioning

confidence: 91%

Evidences for charge‐transfer complex formation in the benzene adsorption on sulfated TiO₂–a resonance Raman spectroscopy investigation

Noda

Rosales

Gonçalves

et al. 2008

J Raman Spectroscopy

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Benzene adsorbed on highly acidic sulfated TiO 2 (S-TiO 2 ) shows an intriguing resonance Raman (RR) effect, with excitation in the blue-violet region. There are very interesting spectral features: the preferential enhancement of the e 2g mode (1595 cm −1 ) in relation to the a 1g mode (ring-breathing mode at 995 cm −1 ) and the appearance of bands at 1565 and 1514 cm −1 . The band at 1565 cm −1 is probably one of the components of the e 2g split band, originally a doubly degenerate mode (8a, 8b) in neat benzene, and the band at 1514 cm −1 is assigned to the 19a mode, an inactive mode in neat benzene. These facts indicate a lowering of symmetry in adsorbed benzene, which may be caused by a strong interaction between S-TiO 2 and the benzene molecule with formation of a benzene to Ti (IV) charge transfer (CT) complex or by the formation of a benzene radical cation species. However, the RR spectra of the adsorbed benzene cannot be assigned to the benzene radical cation because the observed wavenumber of the ring-breathing mode does not have the value expected for this species. Moreover, it was found by ESR measurements that the amount of radicals was very low, and so it was concluded that a CT complex is the species that originates the RR spectra. The most favorable intensification of the band at 1595 cm −1 in the RR spectra of benzene/S-TiO 2 at higher excitation energy corroborates this hypothesis, as an absorption band in this energy range, assigned to a CT transition, is observed.

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“…[1]. Spectroscopic methods (NMR [4], IR [5], UV [6,7] ) are sometimes used to validate proton-indicator interaction. Direct measurements based on the adsorption of Hammett indicators could be misleading because indicator-surface interactions differ from protonation [8,9] since the equilibrium:…”

Section: Direct H O Measurements Indicator Adsorptionmentioning

confidence: 99%

Styrene and styrene dimer derivatives, cyclohexene, tert-butylbenzene and cumene as test reactions for acid strength measurements of crystalline and amorphous silica-aluminas, sulfated oxides and Amberlyst

Marczewski

Marczewska

Popielarska

et al. 2015

Reac Kinet Mech Cat

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The minimal H O values required for cyclohexene, a-methylstyrene, styrene, 2,4-diphenyl-4-methyl-1-pentene, 4-phenyl-1-butene, tert-butylbenzene and cumene to undergo the chosen test reactions over solid acids at 303 K have been established. The chosen reactions and the respective H O min values obtained are as follows: a-methylstyrene and styrene oligomerization (-3.3 and -5.3), 2,4-diphenyl-4-methyl-1-pentene and 4-phenyl-1-butene oligomerization and isomerization (-6.9 and -7.9), cyclohexene oligomerization (-7.8), tert-butylbenzene disproportionation (-10.8) and cumene disproportionation (-11.5). The above mentioned test reactions were used to study the acid strength of different solid acids.

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Superacid and Catalytic Properties of Sulfated Zirconia

Cited by 319 publications

References 0 publications

Valorisation of Vietnamese Rice Straw Waste: Catalytic Aqueous Phase Reforming of Hydrolysate from Steam Explosion to Platform Chemicals

Valorisation of Vietnamese Rice Straw Waste: Catalytic Aqueous Phase Reforming of Hydrolysate from Steam Explosion to Platform Chemicals

Evidences for charge‐transfer complex formation in the benzene adsorption on sulfated TiO₂–a resonance Raman spectroscopy investigation

Styrene and styrene dimer derivatives, cyclohexene, tert-butylbenzene and cumene as test reactions for acid strength measurements of crystalline and amorphous silica-aluminas, sulfated oxides and Amberlyst

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Superacid and Catalytic Properties of Sulfated Zirconia

Cited by 319 publications

References 0 publications

Valorisation of Vietnamese Rice Straw Waste: Catalytic Aqueous Phase Reforming of Hydrolysate from Steam Explosion to Platform Chemicals

Valorisation of Vietnamese Rice Straw Waste: Catalytic Aqueous Phase Reforming of Hydrolysate from Steam Explosion to Platform Chemicals

Evidences for charge‐transfer complex formation in the benzene adsorption on sulfated TiO2–a resonance Raman spectroscopy investigation

Styrene and styrene dimer derivatives, cyclohexene, tert-butylbenzene and cumene as test reactions for acid strength measurements of crystalline and amorphous silica-aluminas, sulfated oxides and Amberlyst

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Evidences for charge‐transfer complex formation in the benzene adsorption on sulfated TiO₂–a resonance Raman spectroscopy investigation