Biphasic kinetic investigations on the evaluation of non-salt forming reductants for Pu(IV) stripping from tributyl phosphate and N,N-dihexyl octanamide solutions in n-dodecane

The relative stability of different oxidation states of actinide elements is influenced by the nature of complexes formed and redox equilibria in aqueous/non-aqueous solutions. The reduction/stripping studies on Pu(IV) ions from loaded organic phases of 1.1 M tributyl phosphate and of 1.1 M N,N-dihexyl octanamide in n-dodecane were studied using organic soluble tert-butyl hydroquinone (TBH) and aqueous soluble reductants like acetaldoxime (AX) and hydroxyurea (HU). These studies were carried out as a function of reductant and nitric acid concentration (0.5–4 M HNO₃) and of time. The changes in Pu oxidation states were followed by spectrophotometry for TBH and by distribution ratio values for AX and HU as reductants. Spectrophotometric investigations using TBH as reductant showed that it was desirable to strip Pu(III) formed after reduction of Pu(IV) in the organic phase, which may otherwise be reconverted to extractable Pu(IV) by in situ generated HNO₂ from oxidative degradation of TBH to tert-butyl quinone. Similarly, the biphasic reduction/stripping of Pu(IV) using AX and HU as reductant rate was affected adversely with increased aqueous phase acidity. This data will help in the accurate simulation of Pu separation processes using these reductants in mixer-settlers/pulsed columns or centrifugal contactors.     

A critical analysis of the effect of crosslinking on the linear viscoelastic behavior of styrene–butadiene rubber and other elastomers

The linear viscoelastic behavior in dynamic shear and tensile creep at temperatures from −30 to 70 °C is measured for an styrene–butadiene rubber (SBR) elastomer cured with dicumyl peroxide to crosslinking densities between 0 and 23.5 × 10⁻⁵ mol/cm³. The G′, G″, and tan δ isotherms are analyzed by time–temperature superposition (TTS), where the tan δ master curves are consistent with those of Mancke and Ferry. However, to achieve the TTS in the lightly crosslinked SBR systems, an anomalous vertical shift is required in the narrow temperature region from 10 to 30 °C. The vertical shift factor in this temperature region is not the standard from rubber elasticity. No anomalous behavior is detected in the equilibrium modulus, which is a linear function of temperature in accordance with the classical theory of rubber elasticity. In contrast to SBR, standard vertical shifts are required to effect TTS for uncrosslinked polybutadiene and an ethylene propylene diene monomer elastomer. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Vesicle Structures from Bolaamphiphilic Biosurfactants: Experimental and Molecular Dynamics Simulation Studies on the Effect of Unsaturation on Sophorolipid Self‐Assemblies

The formation of giant‐vesicle‐like structures by self‐assembling linolenic acid sophorolipid (LNSL) molecules is revealed. Sophorolipids belong to the class of bolaamphiphilic glycolipid biosurfactants. Interestingly, the number of double bonds present in the hydrophobic core of sophorolipids is seen to have a great influence on the type of self‐assembled structures formed. Dye encapsulation results establish the presence of an aqueous compartment inside the LNSL vesicles. Molecular dynamics simulation (MD) studies suggest the existence of two possible conformations of LNSLs inside the self‐assembled structures and that LNSL molecules arrange in layered structures.     

The effect of incorporation of ferrous titanate nanoparticles in sulfonated poly(ether ether ketone)/poly (amide imide) acid-base polymer for cations exchange membrane fuel cells

Journal of Solid State Electrochemistry - The sulfonated poly(ether ether ketone) (SPEEK) is one of the most promising aromatic proton exchange polymer membranes concerning fluorinated aliphatic...     

A Factorial Design Approach for Hydrothermal Synthesis of Phase‐Pure AgInO2: A Parametric Optimization Study

Owing to a wide range of industrial applications and fundamental importance, delafossite compounds have gathered tremendous interest in research community. In this study, the formation of hexagonal nanoplates of AgInO₂ mainly dominated by (00l) facets with no metallic Ag impurity, reported using a facile hydrothermal route at 180 °C using KOH as mineralizer by adopting a factorial design approach. Rietveld analysis of the powder XRD pattern and SAED confirms the rhombohedral system of AgInO₂. FE‐SEM image shows a uniform hexagonal plate‐like morphology with an average width of about 300 nm and thickness of 70 nm. XPS and EDX analysis confirm potassium ion free AgInO₂. A specific surface area of about 48.5 m² g^?1 is arrived from N₂ adsorption studies. Temperature‐dependent AC impedance measurements revealed an activation energy of 0.24 eV/f.u. Further, TG‐DTA studies found that the compound is stable in air up to 595 °C.     

Sulfur Transfer Reactions of Tetrathiomolybdate in Water: Synthesis of Alkyl Disulfides from Alkyl Halides

Abstract: Reaction of a number of alkyl halides with tetrathiomolybdate in water as the solvent affords the corresponding disulfides in good yields.     

Oxidative amidation of benzyl alcohols with amino acid esters mediated by N-hydroxysuccinimide/phenyliodine diacetate

A simple protocol involving metal-free oxidative amidation of benzyl alcohols with amino acid esters has been presented. The amidation proceeds in a radical pathway unlike in conventional metal-mediated extrusion of dihydrogen. The method is advantageous in terms of metal-free conditions, nonexpensive commercial starting substrates. Also various substituents in the starting materials are tolerated and sterically hindered amino acid side chains could provide good yields of amide products.     

Synthesis and structural characterization of Pd(II) thiosemicarbazonato complex: Catalytic evaluation in synthesis of diaryl ketones from aryl aldehydes and arylboronic acids

A simple route to synthesize triphenylphosphinopalladium(II) thiosemicarbazonato complex has been described. Elemental analysis, spectral (IR, NMR) and single crystal X-ray diffraction techniques were employed for the complete characterization of the complex. The latter was found to be effective catalyst for carbon–carbon cross-coupling reaction of aryl- and heteroarylboronic acids with aromatic and heteroaromatic aldehydes to form the corresponding diaryl ketones. The influence of reaction parameters such as solvent, base, reaction temperature and catalyst loading was also investigated.