Electrochemical behaviors of tantalum in anhydrous ethanol containing hydrogen sulfate ions

The electrochemical behaviors of Ta in tetrabutylammonium hydrogen sulfate（TBAHS） ethanol solutions were studied using potentiodynamic polarization,cyclic voltammetry,potentiostatic current time transient and impedance techniques.The results revealed that no active-passive transition is presented in the cyclic voltammogram,and the anodic current density increases with the increase of solution temperature,TBAHS concentration,potential scan rate and water content.The apparent activation energy is about 43.389 kJ/mol and the dissolution process is diffusion-controlled.Potentiostatic measurements showed that the current density gradually decays to a steady value when the potential is low;however,when the potential is higher than a certain value,the current density initially declines to a minimum value and then increases gradually.The resistance of passive film decreases with increasing potential,and inductive loops are presented when the potential is higher than 2.0 V.

Decomposition of a β-O-4 lignin model compound over solid Cs-substituted polyoxometalates in anhydrous ethanol: acidity or redox property dependence?

Production o f aromatics from lignin has attracted much attention. Because of the coexistence of C-O and C-C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for developing a lignin catalytic decomposition process could be developed by exploring the transformation mechanisms of various model compounds. Herein, decomposition of a lignin model compound, 2-phenoxyacetophenone （2-PAP）, was investigated over several ce-sium-exchanged polyoxometalate （Cs-POM） catalysts. Decomposition of 2-PAP can follow two dif-ferent mechanisms： an active hydrogen transfer mechanism or an oxonium cation mechanism. The mechanism for most reactions depends on the competition between the acidity and redox proper-ties of the catalysts. The catalysts of POMs perform the following functions： promoting active hy-drogen liberated from ethanol and causing formation of and then temporarily stabilizing oxonium cations from 2-PAP. The use of Cs-PMo, which with strong redox ability, enhances hydrogen libera-tion and promotes liberated hydrogen transfer to the reaction intermediates. As a consequence, complete conversion of 2-PAP （〉99%） with excellent selectivities to the desired products （98.6% for phenol and 91.1% for acetophenone） can be achieved.

Corrosion Study on Tantalum in Anhydrous Ethanol

The corrosion behavior of tantalum in tetraethyl ammonium chloride （TEA） ethanol solutions was investigated using potentiodynamic polarization, cyclic voltammetry, and impedance techniques along with scanning electron microscopy （SEM）. At the early stage of scanning, the current density in the cyclic voltammetry curves very slowly increased because of the presence of a thin oxide film on the electrode surface. Pitting corrosion then occurred as a result of the passivity breakdown caused by the aggressive attack of the Cl^- anions. SEM images showed the growth process of the pits on the electrode surface. The pitting potential decreased with the increase in TEA concentration but increased with the increase in water concentration. The apparent activation energy of the electrochemical reaction was 36 kJ/mol. The impedance spectra exhibited two time constants for all the potentials. Both the passive layer resistance and the charge transfer resistance decreased with the increase in the potential.

Laboratory Evaluation for Utilization of Phosphogypsum through Carbide Slag Highly-Effective Activating Anhydrous Phosphogypsum

Carbide slag was used as an activator to improve the activity of anhydrous phosphogypsum.Carbide slag could greatly improve the mechanical strength of anhydrous phosphogypsum than K_(2)SO_(4).The compressive strength of 11 wt%carbide slag and 1 wt%K_(2)SO_(4)activated anhydrous phosphogypsum increased greatly to 8.6 MPa at 3 d,and 11.9 MPa at 7 d,and 16.0 MPa at 28 d,respectively.The rate of hydration heat was accelerated and the total hydration heat was increased,and more calcium sulfate dihydrate was formed and cross-linked with other parts which improved the compressive strength of anhydrous phosphogypsum under the effects of different activators.It was indicated that carbide slag was a highly effective and cost-efficient activator.The result provides a highly effective and low-cost method which results in a novel and high value-added method for the utilization of phosphogypsum in the future.

Preparation and characteristic research of anhydrous magnesium chloride with dehydrated ammonium carnallite

Taking the saline lake bischofite and NH4Cl that was removed with the ammonia method and continuously followed by filtration as raw materials with a molar ratio of 1∶1 of MgCl2 to NH4Cl, ammonium carnallite was synthesized. And then the ammonium carnallite was dehydrated to some extent at 160℃ for 4 h. Ammonium carnallite reacted with ammonia at 240℃ for 150 min and the ammonation ammonium carnallite was produced. Finally, the ammonation ammonium carnallite was calcined at 750℃ into anhydrous magnesium chloride containing only 0.1%（mass fraction） of MgO. On the other hand, dehydrated ammonium carnallite was mixed with the solid ammonium chloride at mass ratio 1∶4 at high temperature and with the differential pressure of NH3 above 30.5kPa. The dehydrated ammonium carnallite of mixture was dehydrated at 410℃, and then calcined at 700℃ into anhydrous magnesium chloride with only 0.087%（mass fraction） of MgO. X-ray diffraction and electron microscopy analysis results prove that anhydrous magnesium chloride obtained by both methods hasn’t mixed phases, the particle is large and even has good dispersion, which is suitable for preparation of metal magnesium in the electrolysis.

Density functional theory study of active sites and reaction mechanism of ORR on Pt surfaces under anhydrous conditions

Identifying active sites and catalytic mechanism of the oxygen reduction reaction under anhydrous conditions are crucial for the development of next generation proton exchange membrane fuel cells(PEMFCs)operated at a temperature>100℃.Here,by employing density functional theory calculations,we studied ORR on flat and stepped Pt(111)surfaces with both(110)and(100)type of steps.We found that,in contrast to ORR under hydrous conditions,(111)terrace sites are not active for ORR under anhydrous conditions,because of weakened binding of ORR intermediates induced by O*accumulation on the surface.On the other hand,step edges,which are generally not active for ORR under hydrous conditions,are predicted to be the active sites for ORR under anhydrous conditions.Among them,(110)type step edge with a unique configuration of accumulated O stabilizes O_(2)adsorption and facilitates O_(2)dissociation,which lead an overpotential<0.4 V.To improve ORR catalysts in high-temperature PEMFCs,it is desirable to maximize(110)step edge sites that present between two(111)facets of nanoparticles.

A Safe and Brief Way for Preparing Anhydrous LnCl_3 (Ln=Sc, Y, La to Lu)

Anhydrous lanthanide chlorides LnCl 3 (Ln=Sc, Y, La to Lu except for Pm), which are difficult to prepare in other ways, were prepared by chemical vapor transport (CVT) process. Rare earth oxide reacted with Al 2Cl 6 at 300℃ to produce LnCl 3, which was then separated from other solids by means of CVT at a temperature gradient from 400 to 180℃. Residual Al 2Cl 6 (g) was removed by carrier of dry N 2 gas at 200℃. The yielding rates were >90%, and the purity of products was >99.5%.

Anhydrous ethanol reduces intraoperative hemorrhage of intracranial highly vascularized large meningiomas

Objective:We evaluated the microsurgical effects of intratumoral injection ethanol into intracranial tumors,in particular,those with highly vascularized large meningiomas. Methods: Twelve patients presented with large meningioma,anhydrous ethanol was intraoperatively injected at an average volume of 15.4 mL followed by microscopic tumor resection. Results: Tumors in the injected sites became pallor to various extent and sclerous,leading to significantly decreased hemorrhage on the surface and cut. The average intraoperative hemorrhage was 88 mL. Complete tumor resection was achieved in 11 out of 12 patients; however,only 1 patient had 91.6% of the tumor resected. None of these patients had any postoperative complications. Conclusion: Intratumoral injection of anhydrous ethanol is a safe,convenient,and effective approach to diminish intraoperative bleeding for highly vascularized large meningiomas.

Development of Anhydrous Taphole Clay for Blast Furnace

The application state of anhydrous taphole clay in China and overseas was introduced. The characters and requirements of starting materials of anhydrous taphole clay. for blast furnace, and the formulation and properties of anhydrous taphole clay in some plants were mentioned. The environment problems of anhydrous taphole clay were discussed and the developing trend was pointed out.

20 ppm Anhydrous Ammonia Odor Agent Proposed for Hydrogen Fuel for Safe Detection of Leaks

Preferably 20 ppm anhydrous ammonia (NH3) is proposed to be added to hydrogen fuel (H) made from renewable energy sources (green hydrogen), so that H leaks may be easily detectable by smell, but not dangerously toxic. Including this odor agent, would allow H to be distributed safely in pipes, as required by law, and it would allow H to be safely stored, transported, and exported for sale, and widely commercialized. Further research is suggested to identify optimum pressure, temperature, and automated technique for injecting NH3 into H, and to chart the minimum concentration needed, as a function of temperature and humidity. An application to make hypersonic H burning aircraft safer for ground maintenance crews is proposed. An ability to make, store and distribute H, made from local sources of renewable energy, would reduce a need for fossil fuels, especially in poor, remote communities, where it could improve their economy by creating an export product for sale, while reducing pollution.

Highly Active Anhydrous Potassium Fluoride

Highly active anhydrous potassium fluoride has many uses. Its good performance is demonstrated in high activity, high recovery, low consumption and the low emission of accessory substances during the process of organic fluorination. Moreover. there is no need to use an expensive intertransferable catalyst in the process of fluorination. Under the same conditions and within the same time limit, the fluorination rate of the product is 97% while that of ordinary anhydrous potassium fluoride is 58%. The product, developed recently by the Shenyang Chemical Research Institute, can remain in a state of superfine powder for a long time in air

Anhydrous Taphole Mix For Blast Furnace

This standard specifies the term, definition, brand, label, technical requirements, test methods, quality appraisal procedures, packing, marking, transportation, storage, and quality certificate of anhydrous taphole mix for blast furnace.

A Mild and Practical Procedure for Tetrahydropyranylation of Alcohols and Phenols Catalysed by Anhydrous Ferrous Sulfate

An easy preparation of tetrahydropyranyl (THP) ethers of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) in refluxing dichloromethane has been carried out in good to excellent yields under catalysis of anhydrous ferrous sulfate.

On water in nominally anhydrous minerals from mantle peridotites and magmatic rocks

Trace amount of water associated with the lattice defects of nominally anhydrous minerals （NAMs） can be measured using Fourier transform infrared spectroscopy （FTIR） and secondary ion mass spectrometry （SIMS）. Lots of data on water in NAMs from different lithologies, especially mantle peridotite xenoliths, have been published. The water distribution in olivine from peridotite xenoliths often displays a diffusion profile with high water concentration in the core and low at the rim, which indicates water loss via diffusion during the ascent of host magma. On the other hand, water is homogeneously distributed in pyroxene and its concentration is typically interpreted to represent a mantle value. The water concentration of magma in equilibrium with NAM can be estimated using specific partition coefficient, from which the water content of parental magma and the mantle source can be inferred. The accuracy of this method, however, depends on the selection of appropriate partition coefficient for the system. Using hydrogen isotope compositions and H2O/Ce ratios of mantle NAMs, water source regions can be traced and water heterogeneity can be mapped in the upper mantle. Water plays an important role in the stability of cratonic mantle. The water contents and vertical distribution patterns can be significantly different among different cratonic manties, which may result from different geologic activities. However, the mantle-plume interaction may not necessarily result in significant change of water content in cratonic mantle. The estimation of the water content in the upper mantle is still largely based on geochemical models due to the limitations of data on water in mantle NAMs.

Preparation of anhydrous lanthanum bromide for scintillation crystal growth

This paper reported an efficient and economical method for preparation of anhydrous LaBr3 for scintillation crystal growth. High purity anhydrous LaBr3 powders in large quantities were successfully obtained by stepped dehydration of LaBr3-7H2O using NH4Br as additive. Experiments revealed that adding proper amount of NHaBr could effectively restrain the hydrolysis of LaBr3 during dehydration and thus decreased the yield of deleterious impurity of LaOBr. Optimum preparation conditions, including the amount of NH4Br in use, the dehydration temperature and atmosphere, were investigated by DTA/TG and water/oxygen analysis. The Raman characterization of the as-prepared anhydrous LaBr3 was also presented.

Expanding the dimensionality of proton conduction enables ultrahigh anhydrous proton conductivity of phosphoric acid-doped covalent-organic frameworks

It is of great significance to develop high-temperature anhydrous proton conducting materials.Herein,we report a new strategy to significantly enhance the proton conductivity of covalent organic frameworks(COFs)through expanding the dimensionality of proton conduction.Three COF-based composites,COF-1@PA,COF-2@PA,and COF-3@PA(PA:phosphoric acid),are prepared by PA doping of three COFs with similar pore sizes but different amounts of hydrophilic groups.With the increase of hydrophilic groups,COFs can load more PA because of the enhanced hydrogen–bonding interactions between PA and the frameworks.powder X-ray diffraction(PXRD),scanning electron microscopy(SEM),and two-dimensional(2D)solid-state nuclear magnetic resonance(NMR)analyses show that PA can not only enter the channels of COF-3,but also insert into its 2D interlayers.This expands the proton conduction pathways from one-dimensional(1D)to three-dimensional(3D),which greatly improves the proton conductivity of COF-3.Meanwhile,the confinement effect of 1D channels and 2D layers of COF-3 also makes the hydrogen-bonded networks more orderly in COF-3@PA-30(30μL of PA loaded on COF-3).At 150℃,COF-3@PA-30 exhibits an ultrahigh anhydrous proton conductivity of 1.4 S·cm−1,which is a record of anhydrous proton conductivity reported to date.This work develops a new strategy for increasing the proton conductivity of 2D COF materials.

Methodological progress in trace amounts of structural water in nominally anhydrous minerals

In the deep Earth, hydrogen mainly occurs as structural hydroxyl and molecular water in minerals and melts, constituting mobile and immobile aqueous components. Hydrous minerals contain hydrogen which occupies a specific structural position and constitutes an indispensable component of chemical formulae. On the other hand, nominally anhydrous minerals do not contain hydrogen in their chemical formulae, but can host trace amounts of water in structural position and lattice defect. The molecular water may occur in the lattice defect as fluid/melt inclusions in minerals. Even though the water content of nominally anhydrous minerals is very limited generally in the order of ppm(parts per million), they may play a significant role in influencing the physicochemical properties of mineral and rock systems. With the continuous improvement of modern instrumentations, the analytical methodology exhibits trends for higher spatial resolution, lower detection limit and integral multiple methods on the water amount and its isotopic ratio. Among these methods, Fourier transform infrared spectrometry remains the most widely used, while secondary ion mass spectrometry, continuous flow mass spectrometry, elastic recoil detection analysis and Raman spectrometry are promising. This paper provides a brief review on the methodological progress and their applications to the analysis of structural water in nominally anhydrous minerals.

Dual-sided symmetric crystalline orientation of covalent organic framework membranes for unidirectional anhydrous proton conduction

Two-dimensional covalent organic frameworks(2D COFs)have sparkled wide-ranging research to explore proton-conducting materials.However,the powder-pressed pellets or continuous membranes of 2D COFs are composed of randomly arranged crystallites,which are undesirable for proton transport via a shortcut pathway.We report a controlled strategy for preparing a conformably oriented free-standing COF membrane to address the critical challenge.A monofunctional aldehyde precursor is used as a modulator to enhance reversible association and optimize growth orientation in an interfacial polymerization system.The preferred face-on alignment is achieved throughout the membrane from its flat side to the nanoflake-standing side and,in turn,generates the unidirectional pore channels for accommodating 1,2,4-triazole as proton carriers.The composite merges distinctive features including orientation,crystallinity,porosity,and mechanical strength into one system,exhibiting ultrafast and stable anhydrous proton conduction at high operating temperatures with low activation energy.Our findings offer an innovative strategy for the oriented crystallization of free-standing COF membranes for energy conversion applications.

Ammonium-iodide route to anhydrous EuI_2: mechanism and preparation

Anhydrous EuI2 is an essential raw material for novel Eu^2＋-doped halide scintillators such as SrI2：Eu, CsBa2I5：Eu and BaBrI ：Eu. An efficient and economic method to produce high purity anhydrous EuI2 is critical for future development and applications of these scintillators. In this paper, the ammonium-iodide route to anhydrous EuI2 was investigated, and anhydrous EuI2 with purity of 99.95 wt.% was successfully prepared. The dehydration mechanisms of europium iodide hydrate and its mixture with NH4I were comparatively investigated by X-ray diffraction（XRD）, thermal analysis and fluorescence spectroscopy. The thermal decomposition process of individual europium iodide hydrate was revealed as follows： EuI3·9H2O→EuI 3·8H2O→EuI 3·7H2O→EuI 2·H2O→EuI2, and the hydrolysis mechanism of europium hydrate was comprehensively studied. When europium iodide hydrate was dehydrated with NH4I, NH4Eu2I5 formed as an intermediate product, and the hydrolysis of EuI2 was effectively restrained. The role of NH4I as an iodination agent was also discussed.