Topic
Phosphotungstic acid
About: Phosphotungstic acid is a research topic. Over the lifetime, 1925 publications have been published within this topic receiving 38059 citations. The topic is also known as: Phosphowolframic acid.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: The surface of acid-activated palygorskite (Pa) was modified by grafting 3-aminopropyltriethoxysilane (APTES) for immobilization of phosphotungstic acid (H 3 PW 12 O 40, HPW) as discussed by the authors.
74 citations
••
TL;DR: A solid hybrid molecular material containing 1-butyl 3-methyl imidazolium cations and Keggin anions of phosphotungstic acid has been synthesized.
Abstract: A solid hybrid molecular material containing 1-butyl 3-methyl imidazolium cations and Keggin anions of phosphotungstic acid has been synthesized. It is fully characterized by CHN analysis, FTIR, XRD, UV-Vis-NIR DRS, 31P MAS NMR, TGA and SEM. The FTIR spectrum of the compound shows the fingerprint vibrational bands of both Keggin molecular anions and imidazolium cations. The aromatic C-H stretch region (2700–3250 cm−1) of imidazolium cation is split due to the interaction between the ring C-H and bulky Keggin anion. The red-shift in the UV-Vis spectra and the downfield 31P MAS NMR chemical shift also confirm the electrostatic interaction between the ions in the compound. Near IR spectral region (1000–2500 nm) shows the elimination of water in the compound which is hydrophobic.
74 citations
••
TL;DR: This method represents the first example of the synthesis of isomers from alpha-pinene oxide, other than campholenic aldehyde, with a selectivity that is sufficient for practical usage.
Abstract: The remarkable effect of the solvent on the catalytic performance of H3PW12O40, the strongest heteropoly acid in the Keggin series, allows direction of the transformations of alpha-pinene oxide (1) to either campholenic aldehyde (2), trans-carveol (3), trans-sobrerol (4 a), or pinol (5). Each of these expensive fragrance compounds was obtained in good to excellent yields by using an appropriate solvent. Solvent polarity and basicity strongly affect the reaction pathways: nonpolar nonbasic solvents favor the formation of aldehyde 2; polar basic solvents favor the formation of alcohol 3; whereas in polar weakly basic solvents, the major products are compounds 4 a and 5. On the other hand, in 1,4-dioxane, which is a nonpolar basic solvent, both aldehyde 2 and alcohol 3 are formed in comparable amounts. The use of very low catalyst loading (0.005-1 mol %) and the possibility of catalyst recovery and recycling without neutralization are significant advantages of this simple, environmentally benign, and low-cost method. This method represents the first example of the synthesis of isomers from alpha-pinene oxide, other than campholenic aldehyde, with a selectivity that is sufficient for practical usage.
74 citations
••
TL;DR: In this article, a novel approach to in-situ synthesize and encapsulate phosphotungstic acid into the cavity of MIL-101(Cr) using Na2WO4·2H2O and Na2HPO4 as precursors is presented to increase the acid loading content.
73 citations
••
TL;DR: In this article, a new nanocomposite, CTAB-PTA@CS has been introduced as an efficient and green catalyst for oxidative desulphurization (ODS) process.
73 citations