The study of the electrochemical oxidation mechanism of diphenylamine derivatives in dipolar aprotic solvents: III. Effect of acids and bases of different strengths

The effect of addition of different acids and bases in a wide range of concentration on the voltammetric oxidation of both Variamine blue (VB) and 4-aminodiphenylamine (4-ADPA) was examined in acetonitrile (AcN). The oxidation potential values of either wave of both depolarizers were found to depend on the acid or base strength of the additive—relative to the depolarizer and solvent—and on their concentration in solution. Addition of strong acid as CH₃SO₃H resulted in a single oxidation wave at potentials either equal to or more positive than that of the original second wave. Relatively weak acids as picric and pyridinium ion only shifted the oxidation potential of the first wave to more positive values without affecting the general oxidation pattern.On the other hand, strong bases like ethanolamine, resulted in the formation of a preoxidation wave at more negative potential when present in low concentration and a single wave at identical negative potential at high enough concentrations. Bases of comparable strengths, as that of the depolarizer, like pyridine do not form prewaves but only shifted the final single oxidation wave to more negative potential values. Weaker bases like water and ethanol mainly shifted the oxidation potential of the second wave to less positive values.     

Designing Novel Strategy to Produce Active Nanohybrids in Sunlight for Purification of Water Based on Inorganic Nanolayers,Magnetic Nanocomposites and Organic Species

Energy and water related problems have attracted strong attention from scientists across the world because of deficient energy and water pollution. Following this line, new strategy depended on preparing nanolayers of Al/Zn and magnetic nanoparticles of cobalt iron oxides nanocomposite in addition to long chains of hydrocarbons of stearic acid to be used as roofs, fillers and pillars; respectively, to design optical-active nanohybrids in sunlight for removing the colored pollutants from water in few minutes. By using long chains of hydrocarbons of stearic acid, X-ray diffraction (XRD) results and TEM images showed expansion of the interlayered spacing from 0.76 nm to 2.02 nm and insertion of magnetic nanoparticles among the nanolayers of Al/Zn. The optical properties and activities showed that the nanohybrid structure based on zinc oxide led to clear reduction of the band gap energy from 3.3 eV to 2.75 eV to be effective in sunlight. Photocatalytic degradation of the dye of acid green 1 confirmed the high activity of the prepared zinc oxide nanohybrids because of a complete removal of the dye after ten minutes in sunlight. Finally, this strategy was effective for producing photo-active nanohybrids for using renewable and non-polluting energy for purifying water.     

An investigation on ordered algebraic hyperstructures

In this paper, we present some basic notions of simple ordered semihypergroups and regular ordered Krasner hyperrings and prove some results in this respect. In addition, we describe pure hyperideals of ordered Krasner hyperrings and investigate some properties of them. Finally, some results concerning purely prime hyperideals are proved.     

Chemical Constituents of Polyalthia rumphii

Chemistry of Natural Compounds -     

Extractive separation of Th(IV), U(VI), Ti(IV), La(III) and Fe(III) from Zarigan ore

In this study, the effects of various extraction parameters such as extractant types (Cyanex302, Cyanex272, TBP), acid type (nitric, sulfuric, hydrochloric) and their concentrations were studied on the thorium separation efficiency from uranium(VI), titanium(IV), lanthanum(III), iron(III) using Taguchi^??s method. Results showed that, all these variables had significant effects on the selective thorium separation. The optimum separations of thorium from uranium, titanium and iron were achieved by Cyanex302. The aqueous solutions of 0.01 and 1 M nitric acid were found as the best aqueous conditions for separating of thorium from titanium (or iron) and uranium, respectively. The combination of 0.01 M nitric acid and Cyanex272 were found that to be the optimum conditions for the selective separation of thorium from lanthanum. The results also showed that TBP could selectively extract all studied elements into organic phase leaving thorium behind in the aqueous phase. Detailed experiments showed that 0.5 M HNO₃ is the optimum acid concentration for separating of thorium from other elements with acidic extractants such as Cyanex272 and Cyanex302. The two-stage process containing TBP-Cyanex302 was proposed for separation thorium and uranium from Zarigan ore leachate.     

Improved iodine-125 removal in anionic form of iodate by column method using laterite soil

Soil column experiments have been conducted to treat liquid wastes from hospitals containing¹²⁵I. Three sorbent samples of laterite clay materials with different contents of iron oxides (goethite, -FeOOH) and hydroxides were used to sorb anionic iodate. Post-treatment on effluent wastes with sodium hypochlorite (redox reagent) oxidized the iodide to the desirable iodate ion. Effluent pH after treatment ranges between 4.8 to 5.8, which does not vary much from the initial effluent pH of 4.5 before treatment. Results show that 90 to 97% sorption of iodine radionuclides with a decontamination factor ranges between 10–32 was obtained after the first two hours of experiments. Concentration has decreased from the initial 10 Bq/ml to concentration ranges of 0.3 to 0.9 Bq/ml. Batch experiments conducted using different sorbent masses of soils, show that there was a drop in sorption as the mass of soils fell below approximately 0 to 0.25 g. The sorption remains constant with the soil mass above 0.25 g. Another batch experiment using a different concentration shows that the adsorption capacity of the laterite soil was 1.1 Ci/g. The adsorption is about 96% with a distribution coefficient of 1170.     

A Trigonal‐Pyramidal Erbium(III) Single‐Molecule Magnet

Given the recent advent of mononuclear single‐molecule magnets (SMMs), a rational approach based on lanthanides with axially elongated f‐electron charge cloud (prolate) has only recently received attention. We report herein a new SMM, [Li(THF)₄[Er{N(SiMe₃)₂}₃Cl]?2 THF, which exhibits slow relaxation of the magnetization under zero dc field with an effective barrier to the reversal of magnetization (ΔE_eff/k_B=63.3 K) and magnetic hysteresis up to 3 K at a magnetic field sweep rate of 34.6 Oe s^?1. This work questions the theory that oblate or prolate lanthanides must be stabilized with the appropriate ligand framework in order for SMM behavior to be favored.     

Synthesis,Characterization and Crystal Structure of 4‐Amino‐1,2,4‐Δ2‐triazoline‐5‐thione and its Silver(I) Complex

The reaction of 4‐amino‐1,2,4‐Δ²‐triazoline‐5‐thione (ATT, 1 ) with AgNO₃ in methanol led to the complex [Ag(ATT)₂]NO₃ ( 2 ). 2 was characterized by elemental analyses, ¹H NMR, IR, and Raman spectroscopy as well as single‐crystal X‐ray diffraction. The molecular structure of 1 was also determined by single crystal X‐ray analysis. Crystal data for 1 at ?80 C: space group C2/c with a = 2107.4(2), b = 1425.1(1), c = 688.4(1) pm, β = 104.55(1)°, Z = 16, R₁ = 0.0514, crystal data for 2 at ?80 °C: space group P2₁/c with a = 675.7(1), b = 1321.1(1), c = 1311.2(1) pm, β = 90.03(1)°, Z = 4, R₁ = 0.0437.     

Synthesis,Characterization and Crystal Structure of a Silver(I) Complex containing AMTT (AMTT = 4‐amino‐5‐methyl‐2H‐1,2,4‐triazole‐3(4H)‐thione)

The reaction of 4‐amino‐5‐methyl‐2H‐1,2,4‐triazole‐3(4H)‐thione with AgNO₃ in methanol led to the complex [Ag(ATT)₂]NO₃ ( 2 ). 2 was characterized by elemental analyses, IR, ¹HNMR and Raman spectroscopy as well as single‐crystal X‐ray diffraction. Crystal data for 2 at ?70 °C: space group P2₁/n with a = 1356.7(12), b = 770.4(7), c = 1475.2(12) pm, β = 111.730(15)°, Z = 4, R₁ = 0.0402.