In the preceding papers (1, 2) the preparation and properties of sulfonium salts of methionine were described. The ease of formation of the methylsulfonium salt and the solubility properties of its phosphotungstate suggest utilization for the characterization of methionine in amino acid mixtures, since the phosphotungstates of other a-amino acids are readily soluble in cold aqueous alcohol whil...

The templating effect of the Keggin polyanion derived from phosphotungstic acid (PTA) during the synthesis of NH(2)-MIL-101(Al) has been investigated by means of in situ SAXS/WAXS. Kinetic analysis and structural observations demonstrate that PTA acts as a nucleation site and that it stabilizes the precursor phase NH(2)-MOF-235(Al). Surprisingly kinetics of formation are little changed.

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...

The detailed definition of the structure of DNA in chromosomes and in interphase chromatin is important for correlating the structure of the genetic material with various states of physiological activity. A general approach to developing specific reagents for a variety of such studies in solution and in tissues is to combine a chemically specific organic cation with the electron-opaque phosphot...

Phosphotungstic acid at low pH has been used as a section stain to make visible the surface coats of benign and malignant epithelial cells from human breast biopsies in the electron microscope. For this purpose, tissue is fixed in glutaraldehyde and embedded in the water-soluble plastic glycol methacrylate. Duct epithelial cells from all the biopsies containing benign tissue showed consistently...

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...