Disproportionate Reaction Research Articles

Effect of chemical reaction causing contact angle variation, on the spontaneous motion of an I2-containing nitrobenzene droplet

Spontaneous motion of nitrobenzene droplet including only iodine (potassium iodide-free) in cation surfactant aqueous solution was investigated. For quantitative clarification of the motion mechanism, the contact angle of droplet and the concentrations of iodic components in this system, i.e. I2, I−, IO3−, and I3−, were measured. A disproportionate reaction of iodine in the alkaline conditions to produce iodide and iodate ions was identified, inducing the reduction of the droplet contact angle. A significant relation between running distance of spontaneous droplet motion and the droplet contact angle was found. The mechanism of motion was discussed based on these results.

Inhibitory Effect of Methyl Methanethiosulfinate on β-Glucuronidase Activity

Minced or cut-up leaves of Chinese chive (Allium tuberosum Rottler) contain thiosulfinates and their disproportionate reaction products. Among these organosulfur compounds, methyl methanethiosulfinate was found to be an uncompetitive inhibitor of β-glucuronidase. Approximately 80% of the enzyme activity was inhibited by methyl methanethiosulfinate at 50 µM, the IC50 value being comparable to 3.6 µM.

Mechanisms of NOx entrapment into hydrated cement paste containing activated carbon — Influences of the temperature and carbonation

The NOx pollution produced by road traffic in confined volumes, such as tunnels, is an issue for public health. This work focuses on the mechanisms of NOx removal by modified cement pastes. The samples (made of pure synthetic powders or cement paste cylinders) are continuously exposed to 220ppbv of NO and/or 110ppbv of NO2 gas. The ability for the main hydrates (such as Ca(OH)2 and C–S–H) to trap NO2 is then quantified. After the leaching of samples, the chromatography experiments show that the adsorbed NO2 is transformed in nitrate and nitrite ions by a disproportionate mechanism. The addition of activated carbon into cement paste enhances the NO2 abatement, which is not influenced by carbonation. The NO2 abatement by the activated carbon materials is also stable between 20 and 50°C, revealing a competition between the disproportionate reaction and the gas adsorption.

Preparation of Light-Color Rosin and Preliminary Analysis of Decoloration Mechanism

Color of rosin is an important evaluation quality index. A process for preparing light-color rosin by adding different chemical additives in the reaction was studied. The results showed that the best light-color rosin can be produced by adding TM430 and TM923. Mechanism of decoloration was studied by ultraviolet spectra. The Gardner color of rosin was reduced from 7 to 2 and the acid value and softening point changed a little where the TM430 dosage of 0.2% based on the weight of the starting rosin, in atmospheres of nitrogen for protection, reaction time for 2h. The decoloration mechanism was analyzed with UV.The hydrogen atom generated by disproportionate catalytic reaction with TM430. The color substances in the raw rosin were reduced to colorless by hydrogen atom generated by catalytic of TM430.

Arsenic Sulphide As<sub>4</sub>S<sub>4</sub> Nanoparticles: Physico-Chemical Properties and Anticancer Effects

In this study, arsenic sulphide As4S4nanoparticles have been prepared, by high-energy wet milling, in the presence of sodium dodecylsulphate, which acts a surfactant. Solid state properties of the nanoparticles were characterised by XRD, Raman scattering, specific surface area and particle size distribution. Changes in surface areas of the particles, in the 0.2 - 5.4 m2g-1range, and nanosize distributions, in the 100 - 250 nm range, characterise the surface and morphological properties of nanorealgar. Raman scattering revealed various species in the milled sample that indicate a disproportionate reaction (3As4S4→ 4As2S3+ 4As) occurring as a consequence of milling. Anticancer effects, of the milled species, were confirmed for the human multiple myeloma U266 and OPM1 cell lines. Dissolution experiments in simulated gastric fluid show a possibility for the application of the realgar nanoparticles as an oral dose in future arsenic drug cancer treatments.

Overview of Intellectual/Developmental Disabilities

Patients with intellectual/developmental disabilities (IDD) present many challenges to mental health professionals. The capacity to work with such patients requires a working knowledge of IDD as well as an awareness and understanding of the factors that affect the clinical presentation of mental health disorders across the spectrum of IDD.

Frameworks for risk communication and disease management: the case of Lyme disease and countryside users

Management of zoonotic disease is necessary if countryside users are to gain benefit rather than suffer harm from their activities, and to avoid disproportionate reaction to novel threats. We introduce a conceptual framework based on the pressure-state-response model with five broad responses to disease incidence. Influencing public behaviour is one response and requires risk communication based on an integration of knowledge about the disease with an understanding of how publics respond to precautionary advice. A second framework emphasizes how risk communication involves more than information provision and should address dimensions including points-of-intervention over time, place and audience. The frameworks are developed by reference to tick-borne Lyme borreliosis (also known as Lyme disease), for which informed precautionary behaviour is particularly relevant. Interventions to influence behaviour can be directed by knowledge of spatial and temporal variation of tick abundance, what constitutes risky behaviour, how people respond to information of varying content, and an understanding of the social practices related to countryside use. The frameworks clarify the response options and help identify who is responsible for risk communication. These aspects are not consistently understood, and may result in an underestimation of the role of land-based organizations in facilitating appropriate precautionary behaviour.

Aggressive Foreign Policy as an Instrument for the Legitimization of Putin's Regime

The responsibility of Georgian President Michael Saakashvili for the war with Russia continued to be hotly debated in Georgia, Russia and the world several months after its end.1 Indeed, there are various views about Saakashvili’s decision to attack South Ossetia. By the end of the war, the international community was inclined to recognize the adventurous actions of the Georgian president, but put most of the blame on Moscow for its disproportionate reaction, its bombardment of Georgian cities, its permission to South Ossetian forces to plunder Georgians villages and kill Georgians, as well as its long occupation of Georgian territory.

Elucidation of reaction network and effective control of carbon number distribution in the three phase Fischer–Tropsch synthesis

This article is to deal with the secondary reactions of 1-olefins during Fischer–Tropsch and to selectively synthesize the “FT” products in the desired range (middle distillates and wax) by controlling the pathway reaction shown in the Figure below. In this study, around 90% selectivity in middle distillates and heavy wax has been achieved in olefin-added FT synthesis. We have also experimentally evidenced the disproportionate reaction of 1-olefins in the presence of hydrogen only. Reactions over olefins introduced during FT synthesis have been studied in a trickle bed reactor. Incorporation of 1-olefins into a growing alkyl chain could remarkably enhance the selectivity up to around 90% in heavy wax or middle distillate from syngas and could decrease the yields of lighter hydrocarbons with a higher CO conversion compared to the conventional FT synthesis. Results showed two significant processes the degradation of 1-olefins with successive demethylation, and its chain growth with incorporation by methylene species formed from demethylation, which is defined as the disproportionate reaction. The disproportionate reaction is competitive with introduced 1-olefins incorporating CH 2 species formed from syngas into heavier hydrocarbons and is effectively controllable; Such control strongly depends on the process conditions. In general, the elimination of diffusion limitations for introduced 1-olefins and operating conditions that give a high intrinsic chain growth probability ( α value) are favorable for suppressing the disproportionate reaction and for promoting the chain growth by the incorporation of syngas-formed CH 2 species to increase the yields of heavier FT products.

Effective control of carbon number distribution during Fischer–Tropsch synthesis over supported cobalt catalyst

Effective control of carbon number distribution in FTS has been demonstrated with co-fed 1-olefins in a trickle bed reactor. Addition of 1-octene or 1-dodecene in the n-paraffin solvent could greatly enhance the selectivity of heavy wax and increase the middle distillate to a certain extent directly from syngas, with a marked increase in CO conversion while suppressing the formation of lighter hydrocarbon products compared to the conventional FTS. In the case of co-fed 1-dodecene, the disproportionate reaction was obviously observable, which resulted in a symmetrical product distribution and gave a much higher selectivity in the middle distillate.

A history of research on yeasts 9: regulation of sugar metabolism1

A history of research on yeasts 9: regulation of sugar metabolism1

Method for the synthesis of CrO2 at ambient pressure and temperature

In this article, we report the synthesis of metastable chromium dioxide at ambient temperature and pressure. The formulation of this method is based on the fact that the CrO2 particles used in magnetic recording tapes are chemically unstable and react with the organic binder, leading to a disproportionate reaction that produces nonmagnetic Cr(III)OOH and H2Cr(VI)O4 compounds. This suggests that it is also possible to synthesize CrO2 by reacting Cr(III) with Cr(VI) under appropriate conditions. Thus, metastable chromium dioxide (CrO2) powder was synthesized by mechanically grinding a mixture of CrO3 and Cr(OH)3 to induce a solid–solid reaction at atmospheric temperature and pressure. The characteristics of the product obtained after mechanical grinding of the above mixture depended on parameters such as the preparation conditions for the starting material Cr(OH)3, the grinding time, the rotational speed of the mill and the mole ratio of CrO3 and Cr(OH)3. An x-ray diffraction pattern of the product obtained under optimum conditions was in excellent agreement with the profile of CrO2. Furthermore, the powder was strongly ferromagnetic, with saturation magnetization of 63 emu/g in an applied field of 1 T.

Ｓｍ２Ｆｅ１７Ｎｘ化合物のＨＤＤＲ現象に伴う組織変化

The microstructures of Sm2Fe17 alloys heat-treated in hydrogen and subsequently in a vacuum were observed by transmission electron microscopy (TEM). Sm2Fe17 alloys heat-treated in hydrogen at 600°C for 60 min showed a disproportionate reaction and had a microstructure composed of rod-shaped SmH2 grains and α-Fe. Hydrogen treatment at high temperature (850°C) caused grain growth, and SmH2 grains of 20-100 nm in diameter were observed embedded in an α-Fe matrix. Microstructural observations of the alloy heat-treated in a vacuum at 775°C for 5 min revealed the following recombination reaction process: Fe atoms diffuse into SmH2 grains and react with Sm atoms, resulting in the formation of an Sm2Fe17 compound. After heat treatment in a vacuum at 775°C for 30 min, the recombination reaction is already complete, and the Sm2Fe17 grains have grown to a size of 150-300 nm.

Doping of Bi-Sr-Ca-Cu-O superconductors with Pb, Sn and Ag

Basic and substituted superconductors in the homologous series Bi2Sr2Ca n−1Cu n O2n+4+y , Bi2−x/2Sr2−x/2L x Ca n−1Cu n O2n+4+y and Bi2Sr2−x L x Ca n−1Cu n O2n+4+y (L=Sn, Pb or Ag,x=0−0.4,n=2, 3 or 4) have been synthesized. All the prepared ceramic samples show superconducting behaviour with zero resistance atT c=70 to 85 K. The compounds withn=3 or 4 showed onset temperature around 115K indicating involvement of a disproportionate solid-state reaction and formation of a two-phase system. The phase involving tin or lead oxides showed similar superconducting properties. Final rapid quenching of samples contributed to preservation of the high temperature equilibria with higher solubility of tin oxide in the quaternary system Bi-Sr-Ca-Cu-O. Silver was not soluble but precipitated in a colloidal form at interfaces between the crystalline grains.

Study on the formation of Fe1 − xMnxSi2 from the sintered FeSi-Fe2Si5 eutectic alloy doped with manganese

Abstract The formation and growth of β-FeSi 2 from the sintered eutectic alloy composed of e-FeSi and α-Fe 2 Si 5 doped with manganese has been studied by measuring the electrical resisitivity θ and thermoelectric power Q as well as by X-ray analysis for annealing temperatures from 1073 to 1173 K. The fully annealed specimen of (1 − x ) FeSi 2− x MnSi 2 formed a single β phase in the range 0 ⩽ x ⩽ 0.108, and the lattice parameters of the b and c axes linearly increased with x up to x = 0.108, whereas that of the a axis was independent of x . The ρ and Q values increased with the amount of the β phase, and two peaks with a notch between them were found on the curves of ρ and Q vs . isochronal annealing temperature. The temperatures of the peaks and the notch for the specimen with a manganese concentration of x = 0.01 were 1115, 1135 and 1128 K, decreasing with increasing x . X-ray analysis showed that two different reaction mechanisms operate on the β-phase formation, as for undoped FeSi 2 . One is a two-stage transformation consisting of the disproportionate reaction α → β + Si and the subsidiary reaction Si + e → β below the notch temperature T c ; the other is a simple transformation, i.e. the peritectoid reaction e + → β above T c . The optimum annealing temperature for the formation of the β phase was found to be at the peak of ρ or Q , where the β phase was formed through the two-stage reaction.

Studies on the Radical Polymerization of Methyl Methacrylate in Bulk and in Benzene Using Totally Deuterated Monomer Technique

Totally deuterated methyl methacrylate (MMA-d8) was polymerized with AIBN in bulk at 60°C, and the resultant polymer was analyzed for the initiator fragment by 1H NMR spectroscopy. Amount of the AIBN fragment at the beginning of the chain was found to be 1.15 per molecule, indicating 85% of the polymer molecules formed through disproportionate reaction. NMR analysis of the undeuterated PMMA prepared under the same conditions showed that the polymer contained 0.36 vinylidene double bond at the chain end. This is consistent with the results obtained from the P (MMA-d8). P (MMA-d8) prepared with BPO in benzene at 60°C had 1.20 initiator fragment per chain, 82% of which was phenyl group and 18% benzoyloxy one. Polymerizations in benzene with AIBN in the presence and absence of thiophenol were also examined.

Thermotherapy of VX 2 Rabbit Carcinoma: I: Augmentation by Irradiation

An induction-type radiofrequency generator was used to heat thigh implants of the VX2 rabbit carcinoma. The tumor temperature could be easily raised to over 50 degrees C, while the temperature of normal adjacent muscle generally remained at about 43 degrees C. The marked hypovascularity of the tumor, as demonstrated angiographically, probably explains this disproportionate hyperthermic reaction to administered heat. Twenty-five untreated rabbits succumbed to their tumors after a mean interval of 38 days. Of 24 rabbits with tumors heated to between 48 and 50 degrees C for 30 to 45 min, 5 (21%) were permanently cured. Of 10 rabbits treated with 1000 R in a single dose, none were cured. Of 12 rabbits treated with 1000 R, followed after 3.5 hr with 30 min of heating to 48-49 degrees C, 11 were locally cured. Thus a synergistic effect between hyperthermia and irradiation was demonstrated.

Stability of βMnOOH and manganese oxide deposition from springwater

Beta MnOOH is precipitated preferentially (with respect to Mn3O4) at temperatures near O°C when Mn2+ is oxidized in aerated aqueous solutions. Upon aging in solutions open to the atmosphere a slurry of βMnOOH tends to disproportionate to form MnO2 and Mn2+. In such aged solutions, Mn2+ and H+ activities can be constant, and both the oxidation reaction Mn2++¼O2(aq) + 3/2H2O → βMnOOH (c) + 2H+ and the disproportionate reaction 2βMnOOH (c) + 2H+ → MnO2 (c) + Mn2+ + 2H2O can have positive reaction affinities. It is not possible for both reactions to be in thermodynamic equilibrium in the same system unless oxygen is almost completely absent. A value for ΔGf0 of −129.8±0.6 kcal/mol was obtained for βMnOOH from experimental data by assuming that the reaction affinity for the oxidation reaction is equal to that for the disproportionation. A value for ΔGf0 for βMnOOH of −129.8±0.5 kcal/mol was determined by measuring the redox potentials for the postulated half‐reaction MnO2 (c) + H+ + e− → βMnOOH (c) at 0°, 5°, and 15°C and extrapolating to 25°C. Both these values are consistent with laboratory observations that βMnOOH is less stable than γMnOOH or Mn3O4 at 25°C. Analytical data for manganese‐depositing springwater samples are consistent with a nonequilibrium model involving disproportionation of either βMnOOH or Mn3O4.

POLAROGRAPHY OF THE CIS-DICYANOBIS(ETHYLENEDIAMINE)CHROMIUM(III) COMPLEX

Abstract The cis-[CrIII(CN)2en2]ClO4 complex gave rise to a two-stepped wave responsible for the reductions of Cr(III) to Cr(II) and to Cr(I) state at the dropping mercury electrode(DME) in dimethyl sulfoxide(DMSO). The reduction of the first step is reversible, while that of the second is quasi-reversible. The standard redox potential of the Cr(III)/Cr(II) couple was −1.586 V (vs. aq. SCE). In aqueous solutions containing 0.5 M Na2SO4 or acetate buffer, however, the cis-[Cr(CN)2en2]+ ion gave rise to only one irreversible wave for the reduction of Cr(III) to Cr(II) even in the presence of ethylenediamine in a large excess. Unlike the cases of cis-[Co(CN)2en2]+ and cis-[Co(CN)2dip2]+, the aquation of the resulting Cr(II) complex occurs so fast that a cyanide disproportionate reaction cannot be observed under such conditions.

Reaction between hexacyanoferrate(III) ion and nitric and nitrous acids. Part II. Nature of the intermediate

The structure of an intermediate formed by reaction of nitrogen dioxide with hexacyanoferrate(III) ion is deduced to be a bridged binuclear complex, [Fe2(CN)9(NO)2]3–, on the basis of stoicheiometric, i.r., and Mossbauer evidence. A linear nitrosyl bridge is suggested. The other products, ammonia, carbon dioxide, and cyanogen all suggest that nitrogen dioxide oxidises a cyanide ligand to cyanate, which subsequently decomposes. The intermediate is formed by a disproportionate reaction between two of the [Fe(CN)6]3––NO2 adducts.