An efficient and environmentally benign procedure for synthesis of triarylmethanes is developed via condensation of aromatic aldehydes and N,N-dimethylaniline using small quantity of heteropolyphosphotungstic acid (HPW) as catalyst in water. Good functional group tolerance, simple green experimental procedure, and good to excellent yields of products are the most advantages of this work.

A series of supported phosphotungstic acid (H3PW12O40, HPW) catalysts, including HPW/β, HPW/Sn-β, HPW/H-Y, HPW/H-ZSM-5, HPW/USY, HPW/ReUSY, and HPW/SBA-15, were prepared using an impregnation method for alcoholysis of fructose to ethyl levulinate in ethanol. Among these catalysts, HPW/H-ZSM-5 showed the highest catalytic activity, and the yield of ethyl levulinate from fructose increased with i...

Both Keggin-type phosphotungstic acid (HPW) and Pd are not prominent catalysts towards the oxygen reduction (ORR), but their composite Pd-HPW catalyst produces a significantly higher electrochemical activity for the ORR in acidic media. The novel composite catalyst was synthesized by self-assembly of HPW on multi-walled carbon nanotubes (MWCNTs) via the electrostatic attraction between negative...

core-shell 12-tungstophosphoric acid/tio2 (hpw/tio2) nanoparticles at 10 and 20% of hpw have been synthesized by simple in-situ sol- gel method. characterization of the samples was carried out by x-ray diffraction (xrd), scanning electron microscopy (sem), fourier transform infrared (ftir). the x-ray diffraction patterns of as prepared solid samples, indicated characteristic peaks of titania wi...

Solid-state 13C NMR experiments and quantum chemical Density Functional Theory (DFT) calculations of acetone adsorption were used to study the location of protons in anhydrous 12-tungstophosphoric acid (HPW), the mobility of the isolated and hydrated acidic protons, and the acid strength heterogeneity of the anhydrous hydroxyl groups. This study presents the first direct NMR experimental eviden...

Grafted tungstophosphoric acid (H3PW12O40/ HPW) is applied as a catalyst in the selective catalytic reduction of NOx with NH3 (NH3-SCR). The HPW/CeO2 has been found to be effective SCR reaction compared HPW/SiO2. cobalt-exchanged improved conversion, which reached 98% over wide operating temperature window (280–500 °C). better performance CoPW/CeO2 mainly due higher dispersion tungsten on CeO2 ...

A novel proton exchange membrane using phosphotungstic acid (HPW) as proton carrier and cubic bicontinuous Ia3d mesoporous silica (meso-silica) as framework material is successfully developed as proton exchange membranes for fuel cells. Meso-silica is functionalized by 80wt% HPW using a vacuum impregnation method. The HPW-functionalized meso-silica (HPW-meso-silica) nanocomposites are character...

Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N(2) adsorption-desorption, and SEM techniques. The results showed that the HPW formed...

In this study, three solid acid catalysts, namely mesoporous aluminophosphate-supported 12-tungstophosphoric heteropoly (HPW/MAP), aluminosilicate-supported (HPW/MAS), and gamma alumina-supported (HPW/?-Al2O3) were prepared characterized. Mesoporous aluminophosphate (MAP) aluminosilicate (MAS) synthesized via sol-gel hydrothermal methods, respectively, 25 wt.% of (HPW) was immobilized on the su...

We have developed for fuel cells a novel proton exchange membrane (PEM) using inorganic phosphotungstic acid (HPW) as proton carrier and mesoporous silica as matrix (HPW-meso-silica) . The proton conductivity measured by electrochemical impedance spectroscopy is 0.11 S cm(-1) at 90 °C and 100% relative humidity (RH) with a low activation energy of ∼14 kJ mol(-1). In order to determine the energ...