Zirconium doped mesoporous silica catalysts for dehydration of glycerol to high added-value products

García‐Sancho, Cristina; Moreno‐Tost, Ramón; Mérida‐Robles, J.; Santamaría‐González, J.; Jiménez‐López, Antonio; Maireles‐Torres, Pedro

doi:10.1016/j.apcata.2012.05.015

Cited by 62 publications

(59 citation statements)

References 51 publications

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“…It has been proposed that too many basic sites would lead to formation of macromolecules, such as polyglycerols or acetalization products of glycerol. 33,34 Therefore, ne tuning the amount of basic sites is important. This conclusion is demonstrated in Fig.…”

Section: 34mentioning

confidence: 99%

Effect of Nb doping in WO₃/ZrO₂ catalysts on gas phase dehydration of glycerol to form acrolein

Sung

Cheng

2017

RSC Adv.

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Gas-phase dehydration of glycerol to produce acrolein was investigated over tungstated zirconia catalysts with and without niobium doping, in order to correlate the catalytic activity and life-stability with the acid/ base properties of the catalysts. The results of NH 3 -and CO 2 -TPD experiments showed that the tungstated zirconia catalysts contained both acidic and basic sites, and the amounts decreased with the increase in calcination temperature. The most suitable calcination temperature for 20% WO 3 /ZrO 2 as the catalyst in the gas phase dehydration of glycerol to form acrolein was 450 C in consideration of achieving high acrolein yield and long lifetime of the catalyst. Not only the amount of acid but also the amount of base affected the acrolein yield. Doping a small amount of niobium further increased the life-stability of the catalysts, attributed to the decrease in the number of basic sites. The influence of Nb is mostly in neutralization of surface acidity electronically instead of geometric blocking of the basic sites. Moreover, fine tuning the ratio of acid/base sites was found to be important in achieving good catalytic performance in the gas-phase dehydration of glycerol to generate acrolein. The ratio of acid/base sites in the range of 4-5.4 gave the highest glycerol conversion, and acrolein yield and lowest catalyst decay rate. The spent catalysts were easily regenerated by calcination at 450 C, and the catalytic activities were retained well even after the second time of reuse.

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Section: 34mentioning

confidence: 99%

Effect of Nb doping in WO₃/ZrO₂ catalysts on gas phase dehydration of glycerol to form acrolein

Sung

Cheng

2017

RSC Adv.

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“…3) show the Si O Si asymmetric stretching at 1054 cm −1 with a shoulder about 1160 cm −1 , typical of the SBA-15 support. The presence of zirconium into the SBA-15 produces a slight shift at higher wavenumber, indicating the incorporation of zirconium species into the siliceous framework [47]. The band located about 805 cm −1 is assigned to Si O Si symmetric stretching mode, whereas the vibration at 960 cm −1 may be attributed to the deformation vibration of Si O H groups.…”

Section: Resultsmentioning

confidence: 98%

“…The concentration of both types of acid sites has been estimated from the integrated absorption at 1550 and 1450 cm −1 using the extinction coefficients E B = 0.73 cm mol −1 and E L = 1.11 cm mol −1 for Brönsted and Lewis sites, respectively [47,49]. Although both types of acid sites have been found for all catalysts, after evacuation at 200 • C, the treatment with phosphoric acid increases the C B /C B + C L ratio with respect to catalysts without phosphorous, being this value equal to 0.53 and 0.50 for 12V and 20V catalysts and increasing up to 0.71 and 0.68 for 12VP0.2 and 20VP0.2 catalysts, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The use of mesoporous materials as support, like SBA-15, with high surface area and suitable chemical and thermal stabilities, favors the dispersion of the active phase, increasing the number of acid sites available for the dehydration of glycerol and hence the catalytic activity. Moreover, the incorporation of heteroatoms (Al, Zr or Ti) in the synthesis step of the mesoporous silica generates a high number of acid centers [47].…”

Section: Introductionmentioning

confidence: 99%

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V and V–P containing Zr-SBA-15 catalysts for dehydration of glycerol to acrolein

et al. 2015

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“…In catalysis, silicazirconia mixed oxides are used as an acid catalyst [25], in which the nature of the acidity of the catalyst can be tuned by the silica-zirconia ratio. It is shown by Garcia-Sancho et al [26] that Brønsted acid sites can be generated in Zr-doped MCM-41 by a treatment in steam at 315°C. Qi et al [11] observed an increase in H 2 /CO 2 selectivity during steam treatment of Nb-BTESE derived hybrid silica membranes at 200°C.…”

Section: Water Desorption Behaviormentioning

confidence: 99%

Hydrothermal stability of silica, hybrid silica and Zr-doped hybrid silica membranes

Hove

Luiten-Olieman

Huiskes

et al. 2017

Separation and Purification Technology

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a b s t r a c tHybrid silica membranes have demonstrated to possess a remarkable hydrothermal stability in pervaporation and gas separation processes allowing them to be used in industrial applications. In several publications the hydrothermal stability of pure silica or that of hybrid silica membranes are investigated. To gain deeper insight into the mechanism of hydrothermal stability of silica-based membranes we report a comparison under identical conditions of the gas permeation performance of silica (TEOS), hybrid silica (BTESE) and Zr-doped BTESE (Zr-BTESE) membranes before and after hydrothermal treatments. First, a fast and straightforward hydrothermal stability test at 100°C was applied to screen these membranes. The BTESE and Zr-BTESE membranes maintained their excellent performance after this test, though the TEOS membranes lost their selectivity. Second, hydrothermal tests under water gas shift (WGS) conditions were performed at different temperatures. No significant changes in permeance and selectivity were observed for BTESE derived membranes after a hydrothermal treatment at 300°C. Surprisingly, a large reduction in carbon dioxide permeance was observed for Zr-BTESE hybrid silica membranes after a hydrothermal treatment at 200 or 300°C, resulting in a significant increase of the H 2 /CO 2 permselectivity from 12 to 35.

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Zirconium doped mesoporous silica catalysts for dehydration of glycerol to high added-value products

Cited by 62 publications

References 51 publications

Effect of Nb doping in WO₃/ZrO₂ catalysts on gas phase dehydration of glycerol to form acrolein

Effect of Nb doping in WO₃/ZrO₂ catalysts on gas phase dehydration of glycerol to form acrolein

V and V–P containing Zr-SBA-15 catalysts for dehydration of glycerol to acrolein

Hydrothermal stability of silica, hybrid silica and Zr-doped hybrid silica membranes

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Zirconium doped mesoporous silica catalysts for dehydration of glycerol to high added-value products

Cited by 62 publications

References 51 publications

Effect of Nb doping in WO3/ZrO2 catalysts on gas phase dehydration of glycerol to form acrolein

Effect of Nb doping in WO3/ZrO2 catalysts on gas phase dehydration of glycerol to form acrolein

V and V–P containing Zr-SBA-15 catalysts for dehydration of glycerol to acrolein

Hydrothermal stability of silica, hybrid silica and Zr-doped hybrid silica membranes

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Product

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Effect of Nb doping in WO₃/ZrO₂ catalysts on gas phase dehydration of glycerol to form acrolein

Effect of Nb doping in WO₃/ZrO₂ catalysts on gas phase dehydration of glycerol to form acrolein