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Anhydrous
About: Anhydrous is a research topic. Over the lifetime, 17632 publications have been published within this topic receiving 163495 citations.
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TL;DR: This 3D metal-organic framework (MOF) with acid-base pairs in its coordination space that efficiently conducts protons under both anhydrous and humid conditions has now been developed.
Abstract: The development of solid-state proton-conducting materials with high conductivity that operate under both anhydrous and humidified conditions is currently of great interest in fuel-cell technology. A 3D metal–organic framework (MOF) with acid–base pairs in its coordination space that efficiently conducts protons under both anhydrous and humid conditions has now been developed. The anhydrous proton conductivity for this MOF is among the highest values that have been reported for MOF materials, whereas its water-assisted proton conductivity is comparable to that of the organic polymer Nafion, which is currently used for practical applications. Unlike other MOFs, which conduct protons either under anhydrous or humid conditions, this compound should represent a considerable advance in the development of efficient solid-state proton-conducting materials that work under both anhydrous and humid conditions.
352 citations
TL;DR: During the cleavage of glycosidic linkages by anhydrous hydrogen fluoride there is little or no degradation of the sugars themselves, thus allowing their quantitative recovery, which may also be useful in the analysis of complex polysaccharides.
352 citations
TL;DR: Contrary to expectations, TBAF is stable to Hofmann elimination in polar aprotic solvents under anhydrous conditions and to catalyze proton exchange with DMSO.
Abstract: Tetrabutylammonium fluoride (TBAF) is prepared at low temperature by nucleophilic aromatic substitution of hexafluorobenzene with tetrabutylammonium cyanide Adventitious water is scavenged during this synthesis by the generated hexacyanobenzene, which readily adds water under basic conditions Contrary to expectations, TBAF is stable to Hofmann elimination in polar aprotic solvents under anhydrous conditions Added hydroxylic solvents are shown to catalyze the decomposition of TBAF and to catalyze proton exchange with DMSO The synthetic utility of this salt is described briefly
326 citations
TL;DR: In this article, it was shown that hydrogen saturation in the upper mantle is highly unprobable and that the maximum average amount of hydrogen stored in the nominally anhydrous minerals of the upper manifold is around 600 ppm H 2 O.
Abstract: Several of the supposedly anhydrous major minerals of the upper mantle have been shown to regularly contain small amounts of hydrogen. The concentrations measured in the most important minerals obtained from mantle xenoliths are, expressed in ppm H 2 O, 100-1300 for clinopyroxene, 60-650 for orthopyroxene, 0- 140 for olivine and 1-200 for garnet. Hydrogen is normally structurally incorporated as hydroxyl ions, and in many cases the hydrogen ions seem to act as charge compensators associated with point defects, such as metal vacancies or substitution by mono- or trivalent cations. The determination of the exact amount of hydrogen stored in these nominally anhydrous upper mantle minerals is a key-step toward quantification of the water content of the mantle, as well as understanding of its internal water cycle. For instance, a concentration of 100 ppm H 2 O homogeneously distributed within the upper mantle above 410 km depth is approximately equivalent to a 100 m water layer at the Earth9s surface. However, the relatively fast kinetics of dehydrogenation with concomitant oxidation of iron within these minerals, implies that hydrogen as well as Fe 3+ concentrations in equilibrium with mantle conditions might be different from those measured from recovered xenolith samples. High-pressure experimental measurements of hydrogen solubility as a function of PH 2 O show a trend similar to the hydrogen contents of natural samples, with hydrogen saturation levels that decrease following the mineral series: diopside > enstatite > olivine > pyrope. Except pyrope, these minerals may incorporate more than 1000 ppm H 2 O. Based on recent data of water solubility, stability and partitioning, we suggest that an entire upper mantle saturated in hydrogen is highly unprobable and that the maximum average amount of hydrogen stored in the nominally anhydrous minerals of the upper mantle is around 600 ppm H 2 O. Despite the important progress achieved during the last years, our knowledge of the concentration of hydrogen stored as point defects in the mantle above 410 km is still too poorly constrained. The importance of nominally anhydrous minerals for the water budget of the upper mantle is now well established but still awaits complete quantification.
302 citations
TL;DR: In this article, the thermal decomposition of Ni(NO3)2·6H2O (1), Ca( NO3) 2·4H 2O (2) and nitryl/nitrosyl nitrato nickelate(II), NO2/NO[Ni(NO 3)3] (3), was investigated by thermogravimetric measurements with quasi-isothermal conditions.
294 citations