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.

Heteropolyacids and sulfonic acid-bifunctionalized organosilica spheres for efficient manufacture of cellulose acetate propionate with high viscosity

Abstract: Cellulose acetate propionate (CAP), a high value-added chemical, is traditionally prepared using H2SO4 as catalyst. Replacement of the mineral acids by solid acids is current research focus for green and sustainable production of CAP. Herein, we reported the fabrication of novel solid acid catalyst HPW/Si(Et)Si-Dim-SO3H (Si(Et)Si = ethyl-bridged organosilica and Dim = dihydroimidazole) by incorporating phosphotungstic acid (HPW) and sulfonic acid-based Bronsted acidic ionic liquids onto the organosilica nanospheres of the designed catalyst for efficient manufacture CAP via esterification. The results indicated that the as-prepared HPW/Si(Et)Si-Dim-SO3H with 7.5% HPW loading showed the best catalytic performance at 45 °C in 3 h and the resulting CAP exhibited viscosity of 447 mPa s, Mw of 102,882 and DS of 2.69. Most importantly, the HPW/Si(Et)Si-Dim-SO3H exhibited high catalytic stability over six consecutive cycles and the obtained products were stable too with similar DS, Mw and viscosity. As such, the designed heteropolyacids and sulfonic acid-bifunctionalized heterogeneous catalyst is highly promising for biomass conversion under mild conditions.

Supported phosphotungstic acid catalyst on modified activated carbon for Friedel–Crafts alkenylation of diverse aromatics to their corresponding α-arylstyrenes

Abstract: The supported phosphotungstic acid catalysts on modified activated carbon (PTA/AC) prepared by a facile wet impregnation method were employed for Friedel–Crafts alkenylation of diverse aromatics with phenylacetylene to synthesize their corresponding α-arylstyrenes. Reaction results demonstrate that the fabricated PTA/AC catalyst with 30 wt.% PTA loading exhibits outstanding catalytic performance. The 100% conversion of phenylacetylene with 95.7% selectivity towards α-(2,5-dimethylphenyl) styrene can be achieved over the developed 30 wt.% PTA/AC catalyst under optimized reaction conditions, and no visible loss in catalytic performance can be observed after it suffers from several times recycling. The various characterization techniques including X-ray diffraction, N 2 adsorption–desorption, Fourier transform infrared spectroscopy, and NH 3 temperature-programmed desorption were employed to reveal the relationship between the catalysts nature and catalytic properties. Moreover, the results on the scope of aromatics for the Friedel–Crafts alkenylation illustrate that the developed PTA/AC alkenylation catalyst can be efficiently catalyze the diverse aromatics and even for the electron deficient chlorobenzene. The developed PTA/AC catalyst, using the modified low-cost and sustainable AC as support, may be a robust and promising candidate for highly-efficient and clean α-arylstyrenes production through Friedel–Crafts alkenylation of diverse aromatics including electron-donating and electron-withdrawing groups substituted benzene derivatives as well as heterocyclic and polypolycyclic arenes with phenylacetylene.

Anchoring H3PW12O40 on aminopropylsilanized spinel‐type cobalt oxide (Co3O4‐SiPrNH2/H3PW12O40): A novel nanohybrid adsorbent for removing cationic organic dye pollutants from aqueous solutions

Abstract: Appl Organometal Chem. 2018;e4341. https://doi.org/10.1002/aoc.4341 In this work, phosphotungstic acid (H3PW12O40; PW12) was chemically anchored on aminopropylsiloxane functionalized spherical Co3O4 nanoparticles (Co3O4– SiPrNH2) and the resultant nanocomposite (Co3O4–SiPrNH2/PW12) was fully characterized. The results demonstrated successful anchoring of PW12 on the surface of Co3O4–SiPrNH2nanoparticles. The Co3O4–SiPrNH2/PW12 nanohybrid indicated a specific surface area of 42.14 m g, which was greater than that of pure PW12 (ca. 5 m 2 g). The adsorption efficiency of this novel adsorbent nanomaterial was evaluated for removing methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) dyes from aqueous solutions. The hybrid nanomaterial exhibited a high adsorption rate and selective adsorptivity for the cationic MB and RhB dyes compared to those for anionic MO dye. The prepared hybrid nanomaterial removed over 98% of MB within 12 min. The effects of initial pH, contact time, adsorbent dosage, and temperature were investigated on the adsorption process. The adsorption capacity of nanohybrid for cationic MB dye was 38.46 mg g. Also, adsorption kinetics indicated that the adsorption by Co3O4–SiPrNH2/PW12 was well‐modeled using pseudo‐second‐order kinetic model. Finally, thermodynamic parameters revealed that the adsorption was endothermic and spontaneous. The adsorption rate and ability of the Co3O4– SiPrNH2/PW12 were enhanced as compared with Co3O4 and Co3O4–SiPrNH2 samples due to enhanced electrostatic attraction intraction. The nanohybride was easily separated and reused without any change in structure. Thus, it could be a promising green adsorbent for removing organic pollutants in water.