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.
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TL;DR: In this paper, a 12.12-Phosphotungstic acid supported on porous hydrous zirconia was prepared and characterized by N 2 adsorption isotherm, powder XRD, FTIR, 31 P MAS NMR, H 2 -TPR, NH 3 -TPD, SEM and TEM.
Abstract: 12-Phosphotungstic acid supported on porous hydrous zirconia was prepared and characterized by N 2 adsorption isotherm, powder XRD, FTIR, 31 P MAS NMR, H 2 -TPR, NH 3 -TPD, SEM and TEM. It is found that the chemical interaction of Keggin anions with hydrous zirconia is different compared to the interaction with ZrO 2 and Ce 0.5 Zr 0.5 O 2 supports. The phosphotungstic acid clusters dispersed on porous hydrous zirconia did not show any split of IR bands at 1080 cm −1 ( ν P–O ) and 983 cm −1 ( ν W O,ter ) while those dispersed on ZrO 2 and Ce 0.5 Zr 0.5 O 2 showed a split in these two bands due to the lowering of symmetry of the central PO 4 tetrahedron and direct interaction of W O ter with oxide support. The dispersion of phosphotungstic acid on porous hydrous zirconia led to the growth of crystallites which showed catalytic activity for liquid-phase esterification of 2-ethyl-1-hexanol with acetic acid. Both conversion of 2-ethyl-1-hexanol and selectivity for 2-ethyl-1-hexyl acetate can be achieved at 100%.
30 citations
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TL;DR: In this paper, the first time that H3PW12O40 supported on diamine functionalized MnFe2O4 nanoparticles has been reported, and the synthesized nanoparticle was examined as the heterogenous nanocatalyst for the synthesis of tetrahydrobenzo-[b]-pyran derivatives and 2H-indazolo-[2,1-b]-phthalazine-triones under the solvent-free heating or ultrasonic irradiation conditions.
29 citations
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11 Nov 2011TL;DR: In this article, a method for extracting tungsten from scheelite, which comprises: introducing mixed acid consisted of sulfuric acid and phosphoric acid into a decomposition reactor, heating to 70-100?, and then adding scheelsite, maintaining the solid-liquid ratio at 3:1-8:1L/kg.
Abstract: Disclosed is a method for extracting tungsten from scheelite, which comprises: introducing mixed acid consisted of sulfuric acid and phosphoric acid into a decomposition reactor, heating to 70-100?, and then adding scheelite, maintaining the solid-liquid ratio at 3:1-8:1L/kg, filtrating after 1-6h of reaction, crystallizing the obtained filtrate which is compensated with sulfuric acid consumed by the reaction to obtain phosphotungstic acid crystal, dissolving phosphotungstic acid crystal in water and transforming it to obtain ammonium tungstate solution containing 200-300g/L of WO3, which is used for preparing APT, while returning the obtained crystal mother liquor for ore leaching after being compensated with phosphoric acid and water to the initial level. The invention saves cost of phosphorus-removal reagent and loss of Tungsten; is capable of high efficient scheelite leaching at normal pressure, and overcomes the problems such as Cl- corrosion and heavy volatilization of HCl in traditional acid decomposition process; realizes the recycling of phosphoric acid in general, and greatly reduces the cost of leaching and the quantity of wastewater discharging; and has short flow process, convenient operation, and is adaptive for industrial application.
29 citations
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TL;DR: In this paper, the strength and nature of acid sites of bulk phosphotungstic acid could be modified after dispersing it on silica support which was characterized by XRD, ammonia TPD and 31P MAS NMR techniques.
29 citations
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TL;DR: In this paper, a series of silicon-containing polyacrylate nanoparticles (SiPANPs) were successfully synthesized by simple emulsifier-free emulsion polymerization technique, and the resulting latex particles were characterized by Fourier transform infrared (FTIR) spectrometry, dynamic light scattering (DLS) analysis, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).
29 citations