Extraction of aluminum from alumina by disproportionation process of AlCl in vacuum

The extraction conditions of aluminum by the disproportionation process of A1C1 in vacuum were investigated using alumina and graphite as raw materials, including reaction temperature, pre-reaction and condenser structure. The results show that the extent of the reaction between alumina and carbon increases with increasing reaction temperature at 1643-1843 K; however, the extraction rate of aluminum increases firstly, and reaches the highest at 1743 K, and then decreases with rise in reaction temperature. The pre-reaction of alumina and carbon increases the extraction rate of aluminum. The impurities C, AlaC3 and A1203 in the aluminum product are reduced with reducing the contact surface of the aluminum with CO and with decreasing the condensation temperature, depending on the structure of the condenser.

Thermodynamics on formation of C, Al_4C_3 and Al_2O_3 in AlCl disproportionation process in vacuum to produce aluminum

The formation conditions of C, Al4C3 and Al2O3 in the Al Cl disproportionation process in vacuum to produce aluminum was investigated by thermodynamics analysis. It is demonstrated that the required temperatures for the reactions to form these impurities, the disproportionation of CO and the reactions of metallic aluminum with CO, decrease with decreasing pressure. The lg pCO-1/T diagram of metallic aluminum-CO system agrees with the experimental results, indicating that the reaction rate is very high and this system in vacuum is approximately in equilibrium; therefore, the equilibrium diagram can be used to predict the possible reactions in this system in vacuum.

Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate

Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS （tetraethyl orthosilicate）.Various parameters for preparing catalysts were changed to investigate the suitable conditions.The resulting cata-lysts were tested in a pressured fixed bed reactor and characterized by SEM （scanning electron microscopy）.The conversion of toluene and para-xylene selectivity were influenced remarkably by the n（SiO2）/n（Al2O3） ratio of ZSM-5 zeolite,the type and amount of deposition agent,acid and solvent used,and the time and cycle of deposition treatment.TEOS was proved to be a more efficient agent than the conventional polysiloxanes when the deposition amount was low.The catalyst prepared at the suitable conditions exhibited a high para-xylene selectivity of 91.1% with considerable high conversion of 25.6%.SEM analyses confirmed the formation of a layer of amorphous silica on the external surface of ZSM-5 zeolie crystals,which was responsible for the highly enhanced shape-selectivity.

Carbothermal reduction-chlorination-disproportionation of alumina in vacuum

The carbothermal reduction-chlorination-disproportionation of alumina in vacuum was investigated by XRD and thermodynamic analysis. The experiments on alumina and graphite at 1643-1843 K in vacuum were carried out. The results demonstrate that AlCl3（g） reacts with Al2O（g） or Al（g） generated from the carbothermal reduction of alumina to form AlCl（g）, and the AlCl（g） disproportionates to aluminum and AlCl3（g） at a lower temperature and the reaction rate of AlCl（g） reaches 90% at 980 K and 100 Pa. The aluminum can absorb CO to catalyze its disproportionation to C and CO2, and react backward with CO to form Al4C3, Al2O3, C and CO2, resulting in the aluminum product containing C, Al4C3 and Al2O3. The impurities in the aluminum product decrease as the AlCl（g） disproportionation temperature decreases. AlCl3 condenses at a temperature approximated to the room temperature.

Kinetic Model and Simulation Analysis for Toluene Disproportionation and C9-Aromatics Transalkylation

A new kinetic model for commercial unit of toluene disproportionation and C9-armatiocs transalkylation is developed based on the reported reaction scheme.A time based catalyst deactivation function taking weight hourly space velocity(WHSV)into account is incorporated into the model,which reasonably accounts for the loss in activity because of coke deposition on the surface of catalyst during long-term operation.The kinetic parameters are benchmarked with several sets of balanced plant data and estimated by the differential variable metric optimiza- tion method.Sets of plant data at different operating conditions are applied to make sure validation of the model and the results show a good agreement between the model predictions and plant observations.The simulation analysis of key variables such as temperature and WHSV affecting process performance is discussed in detail,giv- ing the guidance to select suitable operating conditions.

Theoretical Study of the AlCl Disproportionation Reaction Mechanism on the Al(100) Surface

The surface disproportionation reaction mechanism of aluminum subchloride on the aluminum （100） surfaces has been investigated by the plane-wave density functional theory （DFT）. Three kinds of possible reaction mechanism of AlCl disproportionation reaction on the aluminum （100） surfaces have been taken into account. The structures of reactants and products have been optimized, transition states have been confirmed and activation energies have been calculated. The adsorption energy of reactants and desorption energy of products have been determined. All of these have been employed to confirm the reaction mechanism and the rate determining step ofAlCl disproportionation reaction on the aluminum （100） surfaces.

Disproportionation of ethylbenzene in the presence of C_8 aromatics

The selective synthesis of p-diethylbenzene （p-DEB） by disproportionation of ethylbenzene （EB） in the presence of aromatics like m- and p- xylene isomers has been studied over a pore size regulated HZSM-5 catalyst. The industrial feed having different compositions of ethylbenzene and xylene isomers was used for the experimentation. Hence, they were expected to hinder the movement of reactant molecules both on the external surface and within the zeolite channels. It was observed that irrespective of the different feed compositions the concentration of the xylene isomers was intact in the product. There is no other byproducts formation like para-ethylmethyl benzene. The effects of varying the concentration of aromatic compounds in the feed on ethylbenzene conversion and product distribution over the parent and modified H-ZSM-5 catalyst have been discussed. Ethylbenzene disproportionation reaction follows the pseudo first order reaction with an activation energy of 8.6 kcal/mol.

Towards Single-component Molecular Conductor[Ni(dmit)2]by Charge Disproportionation:2[Ni(dmit)2]^0.5→[Ni(dmit)2]+[Ni(dmit)2]^-

A new method of synthesizing single-component molecular conductor [Ni(dmit)2] by the reaction 2(Me4N)[Ni(dmit)2]2 [Ni(dmit)2] + (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2] exhibits a semiconductive behavior above 167 K, while from 167 K down to the measuring limit of 60 K, it exhibits metallic conductivity.

Congenital fiber-type disproportion presenting with type II respiratory failure after delivery:A case report

BACKGROUND Congenital fiber-type disproportion(CFTD)is a form of congenital myopathy.CFTD is rare,especially when presenting in patients with critical illnesses.Here,we report a case of CFTD presenting with type II respiratory failure after delivery and provide a review of the literature on CFTD.CASE SUMMARY A 30-year-old woman was admitted to the obstetrics department of our hospital with premature rupture of the fetal membrane and with 7 h of regular contractions.After delivery,the patient experienced a refractory type II respiratory failure.Physical examination along with diagnostic procedures such as electromyography and biopsy confirmed CFTD.Use of invasive ventilator followed by intermittent use of noninvasive ventilator attenuated her symptoms.The patient recovered after ventilator-assisted respiration and was weaned off the noninvasive ventilator on the seventh day postpartum.CONCLUSION Congenital myopathy should be considered a differential diagnosis for type II respiratory failures that cannot be attributed to other diseases.

Disproportionation Reactions of HIO and NaIO in Static and Dynamic Systems

The paper refers to disproportionation of HIO and NaIO in aqueous media, in static and dynamic systems. The results of calculations, realized according to GATES/GEB principles, with use of an iterative computer program, are presented graphically. An example of the computer program with all physicochemical knowledge involved in the related algorithm is attached herewith.

Mechanically activated disproportionation of NdFeB alloy by ball milling in hydrogen

Mechanically activated disproportionation of Nd 12 Fe 82 B 6 alloy by ball milling in hydrogen atmosphere was experimentally investigated. The aspects of thermodynamics and kinetics for the mechanically activated disproportionation of the NdFeB alloy were discussed. Both the evolution of the disproportionation reaction and the corresponding microstructure change of the alloy during milling were characterized by X ray diffraction (XRD) analysis. The results show that the matrix phase Nd 2Fe 14 B of the as cast Nd 12 Fe 82 B 6 alloy can be disproportionated into a mixture of Nd hydride (H 5Nd 2), FeB/Fe 2B, and α Fe, by ball milling under hydrogen pressure of 0.2 MPa. The as disproportionated phases are of the size about 20 nm, suggesting that ball milling in hydrogen is an effective route for low temperature disproportionation processing of the NdFeB alloy to ensure a full nano structured as disproportionated microstructure. This is the basis for synthesizing Nd 2Fe 14 B/ α Fe nano composites with magnetic exchange coupling effect by subsequent desorption recombination processing.

In-situ synthesis of nanocrystalline TiC powders, nanorods, and nanosheets in molten salt by disproportionation reaction of Ti(Ⅱ) species

A high-efficiency method is developed to in-situ synthesize nanocrystalline TiC powders,nanorods,and nanosheets by using equimolar ratio of Ti powder and acetylene black,multiwalled carbon nanotubes(MWCNTs),and graphene,respectively,as precursor in eutectic Na Cl-KCl molten salt at 800–900℃for 2–3 h.Higher temperature and longer duration are more beneficial for TiC preparation.In addition,mechanism of TiC formation was investigated by linear scan voltammetry.Results indicate that nanocrystalline TiC is in-situ synthesized by reaction between Ti atoms,which come from disproportionation reaction of Ti(Ⅱ)species in the molten salt,and C atoms on the surface of carbon sources.

Electrochemical disproportionation strategy to in-situ fill cation vacancies with Ru single atoms

Supported single-atom catalysts(SACs)possess high catalytic activity,selectivity,and atom utilizations.However,the atom coordination environments of SACs are difficult to accurately regulate due to the high complexity of coordination site and local environment of support.Herein,we develop an in-situ electrochemical cation-exchange method to fill the cation vacancies in MnO_(2)with Ru single atoms(SAs).This obtained catalyst exhibits high mass activity,which is~44 times higher than commercial RuO2 catalyst and excellent stability,superior to the most state-of-the-art oxygen evolution reaction(OER)catalysts.The experimental and theoretical results confirm that the doped Ru can induce charge density redistribution,resulting in the optimized binding of oxygen species,and the strong covalent interaction between Ru and MnO2 for resisting oxidation and corrosion.This work will provide a new concept in the synthesis of well-defined local environments of supported SAs.

Mechanism of dichloromethane disproportionation over mesoporous TiO2 under low temperature

Mesoporous TiO2 was synthesized via nonhydrolytic template-mediated sol-gel route.Catalytic degradation performance upon dichloromethane over as-prepared mesoporous TiO2,pure anatase and rutile were investigated respectively.Disproportionation took place over as-made mesoporous TiO2 and pure anatase under the presence of water.The mechanism of disproportionation was studied by in situ FTIR.The interaction between chloromethoxy species and bridge coordinated methylenes was the key step of disproportionation.Formate species and methoxy groups would be formed and further turned into carbon monoxide and methyl chloride.Anatase(001)played an important role for disproportionation in that water could be dissociated into surface hydroxyl groups on such structure.As a result,the consumed hydroxyl groups would be replenished.In addition,there was another competitive oxidation route governed by free hydroxyl radicals.In this route,chloromethoxy groups would be oxidized into formate species by hydroxyl radicals transfering from the surface of TiO2.The latter route would be more favorable at higher temperature.

Desorption–recombination behavior of as-disproportionated NdFeCoB compacts by reactive deformation

The disproportionated phases of Nd Hx, Fe2B,and a-Fe from Nd2Fe14B were applied to prepare Nd Fe B magnets by two different routes. The results show that the route of annealing in horizontal vacuum sintering furnace cannot reach the purpose of complete recombination after the hot pressing and hot deformation process due to the lack of dehydrogenation channel. The route of applying low pressure of 4–25 MPa on the as-disproportionated green compact during the desorption recombination process in situ hot deformation in a spark plasma sintering（SPS）system can obtain completely recombined Nd Fe B magnet with good anisotropy and magnetic properties. The maximum magnetic properties,（BH）max= 201 kJ m^-3,Br= 1.142 T and Hcj= 469 k A m^-1, are obtained after being treated for 15 min at 750 ℃ under low pressure.

Charge disproportionation induced exchange bias in La_(0.5)Ca_(0.5)FeO_(3-δ)

We observed an exchange bias effect in La0.5Ca0.5FeO3 perovskite compound.The exchange bias is associated with the charge disproportionation transition from Fe4+ions to Fe3+and Fe5+ions below 175 K.The competition between the ferromagnetic interaction of Fe3+and Fe5+ions and the antiferromagnetic one of Fe3+and Fe3+ions results in a unidirectional anisotropy in the cluster-glass system.An antiferromagnetically interfacial exchange coupling constant Ji1.95 meV at the cluster-glass region was yielded by fitting the cooling field-dependence of the exchange bias field.

Hydrogen disproportionation phase diagram and magnetic properties for Nd15Fe79B6 alloy

Transformation-temperature-hydrogen pressure phase diagram was constructed for a Nd15Fe79B6 alloy in order to estimate appropriate conditions for hydrogenation, disproportionation, desorption and recombination reaction （the HDDR）. Optimised recom- bination time （the highest coercivity） was found to be 10 rain. for 5 g samples processed at 740 ℃. Several HDDR processes were carried out at 30 kPa of hydrogen pressure at various temperatures. No correlation between magnetic propertiec and a direction of measurement was observed for the samples processed at 740 ℃. Remanence anisotropy was induced along an alignment direction when the temperature of the HDDR process was increased up to 800 ℃ and 850℃ for 〈100 gm and 100-160 p.m particles, respec- tively. Simultaneously, a small drop in coercivity was observed in the direction of alignment for 〈100 pm particles, but no for 100-160 grn particles. Furthermore, probably an ordered phase was found by TEM microstructure analysis in the bulk sample dis- proportionated at 850 ℃ under 150 kPa of hydrogen. Grains with antiphase domains were observed and corresponding electron dif- fraction patterns were resolved, likely indicating superlattice structures.

Acceleration of disproportionation reactions of aryl alcohols in water medium by CO_2

Compressed CO~ could promote the disproportionation reactions of aryl alcohols in water medium significantly. The control experiments indicated that the effect of CO2 on the properties of the reactant/water emulsions was the main reason for the ac- celeration of the reactions rate.

Pressure-driven symmetry breaking and electron disproportionation of the trigonal Nb_(3)cluster in Nb_(3)Cl_(8)

Symmetry breaking of metal cluster-based strongly correlated systems can give rise to collective phenomena.Here,the twodimensional Nb_(3) cluster compound Nb_(3)Cl_(8) is shown to suffer dramatic symmetry breaking and electron disproportionation under compression.A structural phase transition from trigonal P–3m1 to monoclinic C2/m is observed near 8 GPa with the three-fold symmetry breaking.Electron disproportionation occurs on Nb_(3) clusters from delocalized Nb^(8/3+)Nb^(8/3+)Nb^(8/3+)to localized Nb^(3+)Nb^(3+)Nb^(2+),which results in a subtle bandgap discontinuity,as evidenced by electrical transport and UV-Vis absorption measurements.

紫外分光光度法测定歧化松香中去氢枞酸含量的干扰因素研究

利用液相色谱仪、制备液相色谱仪、气相色谱质谱联用仪,对歧化松香(DR)中去氢枞酸(DA)紫外光谱测定方法的干扰因素进行了详细研究。测定的市售不同省份的5个样品中有2个主要干扰物质,进一步定性,确定干扰物质1为6,8,11,13-枞四烯酸(ATA),干扰物质2为混合物,主要检出物为去氢枞醛(D)和枞酸(AA)。采用二阶导数光谱法和偏最小二乘(PLS)法对紫外光谱数据进行分析,以消除去氢枞酸紫外分光光度法的干扰,结果表明:PLS法比二阶导数光谱法误差更小,能够同时消除多种干扰因素,使测试结果更加接近真实值。