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In situ quantification of the active acid sites of H6P2W18O62·nH 2O heteropoly-acid through chemisorption and temperature programmed surface reaction of isopropanol
(Elsevier Science, 2004-06)
Isopropanol chemisorption and temperature programmed surface reaction analyses were used to determine the nature, amount and acid strength of the active sites of bulk WO3, monolayer supported tungsten oxide over titania ...
Molecular Structure and Thermal Stability of Oxide-Supported Phosphotungstic Wells-Dawson Heteropolyacid
(Royal Society Of Chemistry, 2015-02-12)
We present, for the first time in literature, a systematic study of the molecular structure of the Wells-Dawson heteropolyacid H6P2W18O62.24H2O (HPA) dispersed on TiO2, SiO2, ZrO2 and Al2O3. The heteropolyacid-based ...
The environmentally friendly synthesis of heteropolyacids
(CRC Press-Taylor & Francis Group, 2020)
Fosfotungstic and fosfomolybdic Wells-Dawson heteropolyacids, H6P2W18O62.xH2O and H6P2Mo18O62.xH2O, respectively, were synthesized through ion exchange with a higher yield (~90%) than the conventional organic route (~70%). ...
First Report About the Use of Micellar Keggin Heteropolyacids as Catalysts in the Green Multicomponent Synthesis of Nifedipine Derivatives
(Springer, 2016-06-24)
Micellar Keggin heteropolyacid catalysts were prepared using hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide—CTAB), 1-hexadecyl-pyridinium chloride, and Keggin heteropolyacids H3PMo12O40 and H4PMo11VO40 ...
A suitable synthesis of azlactones (4-benzylidene-2-phenyloxazolin-5-ones and 4-alkylidene-2-phenyloxazolin-5-ones) catalyzed by silica-alumina supported heteropolyacids
(Elsevier Science, 2009-01)
Eleven examples of azlactones (4-benzylidene-2-phenyloxazolin-5-ones and 4-alkylidene-2-phenyloxazolin-5-ones) were prepared via an Erlenmeyer-type synthesis from aromatic aldehydes, hippuric acid and acetic anhydride was ...
Green and efficient synthesis of flavones and chromones using heteropolyacids as catalyst in glycerol
(Bentham Science Publishers, 2018-04-22)
Organic solvents are required to carry out most organic transformations, which cause environmental pollution because of their low volatility. Glycerol, a side product obtained from biodiesel production, has emerged as a ...
Selective Catalytic Dehydration of Xylose to Furfural and Fructose and Glucose to 5‐Hydroximethylfurfural (HMF) Using Preyssler Heteropolyacid
(Wiley-VCH, 2020-04)
Catalytic dehydration of xylose to yield furfural was studied bytesting different heteropolyacid-type catalysts. Preyssler hetero-polyacid (HPA-Preyssler) (H 14 [NaP 5 W 30 O 110 ]) was the mostefficient. Under the optimal ...
Transesterification of rapeseed oil with ethanol: I. catalysis with homogeneous Keggin heteropolyacids
(2007)
Heteropolyacids (HPA) with Keggin structure were evaluated as homogeneous Br∅nsted acid catalysts in the reaction of rapeseed oil transesterification with methanol and ethanol at 358 K and atmospheric pressure. Rapeseed ...