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.

Pyrolysis of D-Glucose to Acrolein

Despite of its great importance, the detailed molecular mechanism for carbohydrate pyrolysis remains poorly understood. We perform a density functional study with a newly developed XYG3 functional on the processes for D-glucose pyrolysis to acrolein. The most feasible reaction pathway starts from an isomerization from D-glucose to D-fructose, which then undergoes a cyclic Grob fragmentation, followed by a concerted electrocyclic dehydration to yield acrolein. This mechanism can account for the known experimental results.

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%.

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.

Theoretical and Electrochemical Characterization of δ-RuCl2(Nazpy)2: Application to Oxidation of D-Glucose

The heterogenized δ-RuCl2(Nazpy)2 deposited on carbon toray (CT) was studied for the first time as electrochemical catalyst. Before, it was characterized by visible-ultraviolet spectra and theoretically by TDDFT method at B3LYP/Lanl2DZ level. It displayed an MLCT t2geg → π* transition where t2geg due to the structure of Nazpy that considerably reduces energy between d AOs of Ru represents the HOMO of the complex and π* is identified as the LUMO. Electrochemistry study shows two redox ranges in both negative and positive sides of the potential. The positive side that corresponds to the couple RuIV/RuIII of catalyst appears to be active for oxidation of D-glucose in carbonate buffer with a high turnover. Therefore, Keto-2-gluconic and gluconic acids were the two main products obtained with respectively 80% and 17.6% of selectivity. Moreover, a small amount of tartaric and glycol acids coming from the c-c bond cleavage due to non-protection of the anomeric carbon of D-glucose were also observed.

Optical Rotatory Dispersion Measurement of D-Glucose with Fixed Polarizer Analyzer Accessory in Conventional Spectrophotometer

In the sample compartment of a conventional spectrophotometer, mounting of a polarizer before sample and an analyzer behind sample allows the determination of the optical rotatory dispersion of optical active media by measurement of the transmission ratio of crossed and parallel arranged polarizer and analyzer. A formula for the determination of the angle of rotation is derived from the transmission ratio. The arrangement is applied to determine the molar optical rotation of D-glucose in water in the wavelength range from 220 nm to 820 nm.

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.

Densities and Viscosities of the Quaternary System Mannitol-Sorbitol- D-Glucose-H2O and Its Ternary Subsystems at 298.15K

To check the applicabilities of the simple density equation and viscosity equation in the semi-ideal solution theory to nonelectrolyte solutions, the densities and viscosities were measured for the quaternary system mannitol-sorbitol-D-glucose-HzO and its ternary subsystems mannitol-D-glucose-H2O and sorbitol-D-glucose-H2O at 298.15K. The results were used to test the applicability of the simple equations for the density and viscosity of the multicomponent nonelectrolyte solution. The agreements between the predicted and measured results are good.

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.

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.

Anomeric specificity of D-glucose metabolism study in rat and human erythrocytes

The anomeric specificity of D-glucose metabolism in erythrocytes has been since 1985 the matter of extensive investigations reported in about ten publications. The present report aims at providing an integrated review of the major findings on this issue.

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.

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

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.

Activation of Anhydrate Phosphogypsum by K_2SO_4 and Hemihydrate Gypsum

Lime pretreated phosphogypsum（PG） was calcined at 500 ℃ to produce anhydrate gypsum cement. Due to the slow hydration of anhydrate gypsum, additives, K2SO4 and hemihydrate gypsum were selected to accelerate the hydration of anhydrate. The hydration characteristics, the resistance to hydrodynamic water, and the mineralogical studies were investigated. The experimental results suggest that activated by K2SO4 and hemihydrate, anhydrate PG hydrates much more rapidly than that in the presence of only K2SO4 or in the absence of additives. The binder has proper setting time, good strength development, and relatively better resistance to water. The hardened binder has hydrated products of rod or stick like shaped dihydrate gypsum crystals.