Superacids Based on Zirconium Dioxide

Brei, V. V.

doi:10.1007/s11237-005-0035-7

Cited by 24 publications

(15 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The intensity observed for SZr is more than that of Zr. Generally, incorporation of various promoter atoms such as lanthanum, cerium and yttrium into the zirconia lattice stabilizes the tetragonal phase [24]. The present results are thus in line with earlier observations.…”

Section: X-ray Diffraction (Xrd) Analysissupporting

confidence: 93%

Eco Friendly Nitration of Toluene using Modified Zirconia

Devi

Jayashree

2013

Bull. Chem. React. Eng. Catal.

View full text Add to dashboard Cite

Nitration of toluene has been studied in the liquid phase over a series of modified zirconia catalysts. Zirconia, zirconia- ceria (Zr0.98Ce0.02)O2, sulfated zirconia and sulfated zirconia- ceria were synthesised by co precipitation method and were characterised by X-ray diffraction, BET surface area, Infra red spectroscopy analysis (FTIR), Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM) and Energy Dispersive X ray analysis (EDAX). The acidity of the prepared catalysts was determined by FTIR pyridine adsorption study. X-ray diffraction studies reveal that the catalysts prepared mainly consist of tetragonal phase with the crystallite size in the nano range and the tetragonal phase of zirconia is stabilized by the addition of ceria. The modified zirconia samples have higher surface area and exhibits uniform pore size distribution aggregated by zirconia nanoparticles. The onset of sulfate decomposition was observed around 723 K for sulfated samples. The catalytic performance was determined for the liquid phase nitration of toluene to ortho-, meta- and para- nitro toluene. The effect of reaction temperature, concentration of nitric acid, catalyst reusability and reaction time was also investigated. © 2013 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

show abstract

Section: X-ray Diffraction (Xrd) Analysissupporting

confidence: 93%

Eco Friendly Nitration of Toluene using Modified Zirconia

Devi

Jayashree

2013

Bull. Chem. React. Eng. Catal.

View full text Add to dashboard Cite

show abstract

“…222 Several authors even report that, when using fructose / sulfated zirconia system, final HMF yields of 65.6% and 29.9 were obtained in acetone-DMSO and water, respectively. 273 DMSO has proved to accelerate the HMF formation, delaying its hydrolysis. 132 It also inhibits the formation of LA because it does not allow HMF to rehydrate.…”

Section: Effect Of the Solventmentioning

confidence: 99%

The challenge of converting biomass polysaccharides into levulinic acid through heterogeneous catalytic processes

Covinich

Clauser

Felissia

et al. 2019

Biofuels Bioprod Bioref

View full text Add to dashboard Cite

The differences between a biorefinery and an oil refinery are determined by the higher oxygen content of the biorefinery's biomass, its high degree of functionalization, its low thermal stability, its polar components, which are mostly acidic, its highly heterogeneous structure, and its quality variation as result of genotypic and phenotypic characteristics. Levulinic acid (LA) is one of the main high value‐added chemicals that can be produced from lignocellulosic biomass as raw material. The main challenges for the conversion of lignocellulosic biomass to levulinic acid are related to the improvement of the technologies to obtain a pure and cost‐competitive product, the design and use of efficient heterogeneous catalysts, and the improvements in the selectivity and useful life of the catalyst. This is an up‐to‐date review of the state of knowledge about the heterogeneous catalytic conversion of biomass into LA, addressing the technical hurdles that impede the attainment of high yields. This work outlines the chemistry of LA synthesis and discusses in detail the influence of the lignocellulosic raw material, reaction time, temperature, solvent according to the chemical pathway, and efficiency of the chosen Lewis and Brønsted solid acid catalysts. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

show abstract

“…During the last 25 years, significant attention has been devoted to synthesis and study of stable solid superacids, such as sulphated [2] and tangstated [3] zirconia. These oxides effectively catalyze many important reactions at average temperatures, for instance isomerization of linear alkanes and acylation of aromatic compounds [2,3]. However, at present the synthesis of solid acids which occupy the intermediate position between zeolites with their acidity function value (Н 0 ≥ -8) and the superacid catalysts (Н 0 ≤ -12) is of interest.…”

Section: Introductionmentioning

confidence: 99%

“…Relatively low specific surface area, which is lower than 100 m 2 /g [3], is a certain disadvantage of superacids on the basis of zirconia. This is connected with the high coordination number for Zr 4+ ions (7 and 8) and, correspondingly,…”

Section: Introductionmentioning

confidence: 99%