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.

Composite catalyst for preparing sec-butyl acetate with direct esterification of ethyl ester and butylene

Abstract: The present invention relates to a composite catalyst for preparing sec-butyl acetate by direct esterification of ethyl ester and butylene, which takes heteropoly acid as the catalyst active component and porous carrier as the dispersant; the weight proportion of the heteropoly acid and the porous carrier is 001:1 to 10:1 The heteropoly acid is one with Keggin structure, which consists of phosphotungstic acid, silicotungstic acid, germanium tungstic acid, arsenowolframic acid, phosphomolybdate, germanomolybdate or arsenicomolybdate The porous carrier comprises porous SiO2, Al2O3, SBA-15, MCM-41, white carbon black, porous SiC, corallite, andalusite, cordierite, meerschaum, Attapulgite or kaolin The composite catalyst of the present invention solves the problem that the catalysis efficiency is low if the heteropoly acid is separated out from the reaction system

The effect of acid-base interaction on the thermal and transport properties of poly(etheretherketone) based composite membranes

Abstract: Binary composite membranes were prepared by the solution casting method from sulfonated poly(etheretherketone) (SPEEK) and organic additives such as hydroxyquinolinesulfonicacid (HQS), 4-tertiary butylpyridine (TBP), imidazole and succinimide. Ternary composite membranes were prepared from SPEEK, inorganic phosphotungstic acid (PWA) and the same organic additives. The acid base interaction characteristics of the composite membranes were not observed by ATR-FTIR analysis. TGA results showed that the thermal stability of the composite membranes was enhanced in the temperature range up to about 400 °C by the addition of the organic additives. The acid-base interaction between SPEEK and the organic additives of HQS, TBP and imidazole decreased the water uptake, methanol permeability and proton conductivity of the binary and ternary composite membranes. However, the addition of succinimide did not decrease the water uptake, proton conductivity and methanol permeability of the composite membranes. The composite membranes containing succinimide made little acid-base interaction but made hydrogen bonding with SPEEK. The hydrogen bonding proved to be weaker than the acid-base interaction. The selectivity of the composite membranes increased by the addition of PWA, and the selectivities of the composite membranes containing succinimide were higher than those of the other composite membranes.

Nanocomposite Proton Exchange Membranes Based on Sulfonated Poly (2,6-Dimethyl-1,4-Phenylene Oxide) with Enhanced Performance for Fuel Cell Applications

Abstract: A series of composite membranes based on sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) comprising phosphotungstic acid (PWA) were fabricated and investigated as polymeric electrolytes for hydrogen/oxygen fuel cell (PEMFC) applications. Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) matrices were first sulfonated to different extents to determine the maximum possible sulfonation degree, which ensures the highest proton conductivity as hydrolytic stability was not sacrificed. Subsequently, 20 wt% of PWA as a strong solid super acid was added into sulfonated polymeric matrices. Prepared composite membranes were characterized for their different properties including water uptake capacity, proton conductivity, and hydrolytic stability. The results of conductivity measurements revealed that in the presence of PWA molecules the proton conductivity of SPPO membranes with sulfonation degree of 40% was improved from 1.82 × 10−2 S cm−1 to 2.57 × 10−2 S cm−1 at 25°C. The improved proton conductivity of the S...