Catalysis by Ir(III), Rh(III) and Pd(II) metal ions in the oxidation of organic compounds with H2O2

Catalytic activities of three transition metals, as iridium (III) chloride, rhodium (III) chloride and palladium (II) chloride, were compared in the oxidation of six aromatic aldehydes (benzaldehyde, p‐chloro benzaldehyde, p‐nitro benzaldehyde, m‐nitro benzaldehyde, p‐methoxy benzaldehyde and cinnamaldehyde), two hydrocarbons (viz. (anthracene and phenanthrene)) and one aromatic and one cyclic alcohol (cyclohexanol and benzyl alcohol) by 50% H₂O₂. The presence of traces (substrate: catalyst ratio equal to 1:62500 to 1:1961) of the chlorides of iridium(III), rhodium(III) and palladium(II) catalyze these oxidations, resulting in good to excellent yields. It was observed that in most of the cases palladium(II) chloride is the most efficient catalyst. Conditions for the highest and most economical yields were obtained. Deviation from the optimum conditions decreases the yields. Oxidation in aromatic aldehydes is selective at the aldehydeic group only and other groups remain unaffected. This new, simple and economical method, which is environmentally safe, also requires less time. Reactive species of catalysts, existing in the reaction mixture are also discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Thermal effects on parallel resonance energy of whistler mode wave

In this short communication, we have evaluated the effect of thermal velocity of the plasma particles on the energy of resonantly interacting energetic electrons with the propagating whistler mode waves as a function of wave frequency and L-value for the normal and disturbed magnetospheric conditions. During the disturbed conditions when the magnetosphere is depleted in electron density, the resonance energy of the electron enhances by an order of magnitude at higher latitudes, whereas the effect is small at low latitudes. An attempt is made to explain the enhanced wave activity observed during magnetic storm periods.     

HPTLC Determination of Swertiamarin and Amarogentin in Swertia Species from the Western Himalayas

JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatographic (HPTLC) method has been established for simple and rapid quantification of two...     

On the stability of the output characteristics of a grazing incidence grating dye laser transversely pumped by a copper vapor laser

The output characteristics of a high repetition rate pulsed dye laser has both short-term fluctuations and long-term drift. In high power high repetition rate lasers flow induced variations dominate over those due to other factors. In this paper it is shown by dye laser measurements that bandwidth fluctuations can be traced to the effective changes of the resonator dispersion due to fluctuations in the penetration depth of the pump beam in the dye medium. Short-term wavelength fluctuations can be traced to instantaneous deflection of the dye laser axis by the refractive index changes due to absorption of the pump beam. The fluctuations in both the bandwidth and the wavelength decreases with increasing flow rates within a laminar region. A copper vapor laser operating at 5.6 kHz repetition rate pumped the Rhodamine 6G dye laser used. The wavelength fluctuation of ±0.0035, 0.0030, 0.0004 nm and the bandwidth fluctuation of ±710, 132, 45 MHz over approx. 60 minutes were observed at 1.2, 3.7, 5.5 lpm flow rates respectively.     

Head-group-influenced mixed micellization of sodium deoxycholate with conventional hydrocarbon surfactants of identical hydrocarbon tails

Conductivity, viscosity, turbidity, and NMR measurements were performed over most of the mole fraction range for sodium deoxycholate (SDC) with hexadecyltrimethylammonium bromide (HTAB), hexadecylpyridinium bromide (HPyBr), and hexadecylpyridinium chloride (HPyCl). All studies demonstrate that the mixed-micelle formation is more favorable in SDC plus HTAB rather than SDC plus HPyBr or SDC plus HPyCl mixtures. The results showed that the bulky pyridinium head groups of HPyBr or HPyCl create steric incompatibility with rigid SDC monomers in the mixed state.     

Muon spin resonance and repolarization in amorphous silicon monoxide (a-SiO)

Studies of the muonium fractions in the amorphous oxide a-SiO have been carried out by RF resonance at TRIUMF, Canada and LF repolarization techniques at RAL, U.K. The resonance measurements confirm the presence of the interstitial Mu centre in this intermediate oxide of silicon. Analysis of the data gathered at RAL, using a recently-developed fitting technique, reveals that the Mu^* state is present here as well, but with lower relative fractions than in a-Si. However, as in the latter material, but in contrast to c-Si, this bond-centre species appears to be stable up to room temperature.     

Upper consolute temperature of water-phenol systems with some additives

Using upper consolute temperatures (UCT) and corresponding consolute compositions (CC) of water-phenol systems with each of 0.1 mol kg^?1 salts and acids, 1.0% polyethylene glycol 200, 0.01 mol kg^?1 surfactant and aromatic compounds, we obtained 0.01 mol kg^?1 CaF₂ and CrCl₃ compositions. Focusing on UCT and CC, the role of valence electrons and shell number, basicity, hydrophilic, hydrophobic and π conjugated electrons of corresponding additives are reported. The surfactants and π conjugation electrons are noted to decrease the UCT in a constant ratio that depicts the state and inherent strength of ionic and molecular-water interactions. The data are useful in the investigation of cloud points of immiscible solutions based on the Hofmeister series.     

Working group report: Neutrino and astroparticle physics

This is the report of neutrino and astroparticle physics working group at WHEPP-7. Discussions and work on CP violation in long baseline neutrino experiments, ultra high energy neutrinos, supernova neutrinos and water Cerenkov detectors are discussed.