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.

Method for extracting tungsten from phosphotungstic acid/phosphotungstate solution

Abstract: The invention relates to a method for extracting tungsten from a phosphotungstic acid/phosphotungstate solution. The method comprises following steps: (1), hydrogen peroxide is added to the phosphotungstic acid/phosphotungstate solution, and a mixed solution containing peroxo-tungstic acid is obtained; (2), tungstic acid is precipitated with a reduction reaction or a decomposition reaction, filtered and washed, and a tungstic acid precipitate and a filtrate are obtained; (3), tungstic acid is calcined, and tungsten trioxide is prepared; or, tungstic acid is dissolved in ammonia water, an ammonium tungstate solution is prepared, and APT (ammonium paratungstate) is prepared through evaporative crystallization; (4), the filtrate returns to the phosphotungstic acid/phosphotungstate solution for recycling. According to the method, existence forms and characteristics of various species in a mixed acid solution system are taken into consideration, and tungsten obtained through extraction can be directly used for preparing tungsten products; the method has the advantages of good separation effect, simple and easily controlled operation process and easiness in industrial popularization and application.

Phosphotungstic Acid Nanoclusters Grafted onto High Surface Area Hydrous Zirconia as Efficient Heterogeneous Catalyst for Synthesis of Octahydroquinazolinones and β-Acetamido Ketones

Abstract: Phostungstic acid (PWA) nanoclusters grafted onto high surface area polycrystalline hydrous zirconia powder (PWA/ZrO2) was prepared by wet impregnation method. The zirconia particles were synthesized using a modified sol–gel route. The obtained material was characterized by X-ray diffraction (XRD), UV–Vis–diffuse reflectance spectroscopy (UV–Vis–NIR–DRS), infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and sorptometric techniques. XRD study revealed the presence of tetragonal phase of zirconia in the synthesized sample. TEM study indicates presence of small PWA clusters with size in the range of 5–15 nm well dispersed on the surface of the ZrO2 particles. The characteristic UV and IR absorption feature of the PWA was retained in the PWA/ZrO2 material. The PWA/ZrO2 material was used as an efficient catalyst for the preparation of octahydroquinazolinones and β-acetamido ketones. The octahydroquinazolinones were synthesized by the multicomponent condensation of dimedones, urea and aryl aldehydes in ethanol. Similarly, β-acetamido ketones were synthesized with high yield and purity by four component condensation of aryl aldehydes, enolizable ketones, and acetyl chlorides in acetonitrile. The protocols developed in this investigation using the PWA/ZrO2 catalyst is advantageous in terms of simple experimentation, high yield and purity of the products and recovery and reutilization of the heterogeneous catalyst.

Preparation of carbonyl sulfide and production of methyl mercaptan therefrom

Abstract: Methyl mercaptan is prepared by hydrogenating carbonyl sulfide in the presence of a sulfactive catalyst The carbonyl sulfide is prepared by reacting carbon dioxide and carbon disulfide in the presence of a supported phosphotungstic acid catalyst

Heteropolyacid ionic liquid and application of heteropolyacid ionic liquid in oxidative desulfurization

Abstract: The invention provides a method for preparing a phosphotungstate heteropolyacid ionic liquid and application of phosphotungstate heteropolyacid ionic liquid in diesel oxidative desulfurization. The ions in the ionic liquid comprise phosphotungstic acid anions having a Keggin structure and [C18H20N4O4] organic cations and a catalyst has the general structure of 1,1'-[1,3-phenylenebis(methylene)]bis[3-(carboxymethyl)]-1H-imidazole dihydrogen phosphotungstate. The ionic liquid disclosed by the invention is used as an oil oxidation desulfurization catalyst and has the advantages of being small in usage amount, high in catalytic activity and fast in desulfurization speed and can be recycled and is easy to separate and the like.

Synthesis of mesoporous silica-zirconia supported phosphotungstic acid and its catalytic performance for oxidative desulfurization of fuel

Abstract: Mesoporous silica-zirconia supported phosphotungstic acid was synthesized by evaporation induced self-assembly method and used as oxidative desulfurization catalysts. The structural properties of as-prepared catalysts were characterized using various analytical techniques including X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and nitrogen adsorption desorption. The experimental results showed that HPW was highly dispersed on mesoporous framework. The surface acidity of catalysts was analyzed by FTIR measurement of adsorbed pyridine.The surface Lewis acidity was improved with increasing the content of zirconium in the samples. The mesoporous composites were used as catalysts with H2O2 as oxidant for oxidative desulfurization of model fuel. The catalytic activity results showed that the surface Lewis acid sites acted as selective adsorption active sites for dibenzothiophene, which facilitated the sulfur removal from model fuel in the presence of arene. A slight decrease in activity of the recovered catalyst used in the proceeding rounds indicated the reusability of the catalyst.