Highly efficient epoxidation method of olefins with hydrogen peroxide as terminal oxidant, bicarbonate as a co-catalyst and oxodiperoxo molybdenum(VI) complex as catalyst

A combination of the newly synthesized and structurally characterized compound, [MoO(O2)2(saloxH)](saloxH2= salicylaldoxime) as catalyst, H2O2 as terminal oxidant and NaHCO3 as co-catalyst when stirred in CH3CN (10 cm3) at room temperature (rt) shows a very pronounced efficiency epoxidation of olefinic compounds, the method being green and economical.     

Density, ultrasonic velocity, surface tension, excess volume and viscosity of quaternary fluid solutions

Density, ultrasonic velocity, surface tension, excess volume and viscosity of quaternary non-electrolyte solution n-pentane+tolune+n-heptane+cyclohexane has been experimentally determined at 25 °C over a wide range of composition. Assuming a quaternary fluid solution to be made of six binaries, a statistical approach of Prigogine–Flory–Patterson (PFP) theory has been extended to develop the expressions for dynamic viscosity, surface tension excess volume and ultrasonic velocity of quaternary fluid system. A reasonable agreement has been achieved between theory and experiment. An attempt has also bee made to explain the nature of molecular interactions involved in the light of excess thermodynamic functions whose sign and magnitude depend upon the chain length and size of the component fluids and also studied the role of order breakers (toluene and cyclohexane) on these properties.     

Synthesis and Properties of Mixed Ligand Complexes of Diorganotin(IV): Part(VII) – Synthesis and Characterisation of Some Antibacterial Dibenzoylmethane Diorganotin(IV)‐O‐alkyl Trithiophosphates

A series of some new mixed ligand complexes have been synthesized with an objective for evaluation as antimicrobials. Reactions of diorganotin(IV) dichloride with dibenzoyl methane and O‐alkyl trithiophosphates in a 1:1:1 molar ratio in refluxing benzene yield products of the type [PhCOCHCOPh]R₂Sn‐[SSH(S)POR'] [where R = Me, Bu, Ph; R' = Me, Et, Prⁱ, Buⁱ, Ph]. The newly synthesized complexes are light yellow colored crystalline solids, non‐volatile, soluble in common organic solvents, monomeric in nature and highly sensitive towards atmospheric moisture. These complexes are characterized by elemental analysis, IR and multinuclear NMR (¹H, ³¹P and ¹¹⁹Sn) spectral studies. Spectral studies of these complexes indicate that dibenzoyl methane and O‐alkyl trithiophosphate moieties are bidentate and the central tin atom is hexacoordinated in nature. A few of these compounds were tested for their antibacterial activity using standard drugs.     

Privacy and pricing personal information

The issues we address here are – How should a firm (e.g. Internet service provider (ISP)) that is capable of collecting personal information (browsing information, purchase history, etc.) about consumers, price its service, given that consumers vary in their valuation for privacy, and also vary in terms of the value of their personal information to a third party (firms that need consumer information)? Should the firm have a blanket policy of never collecting, or a policy of always collecting and revealing information? Surprisingly we find that in some cases the collector of information may be no worse off in the asymmetric information case than in the full information case. The paper provides a justification for the strategy of some firms such as ISP’s which never collect information and also for the strategy of other firms, like grocery stores that do. We also find that it is non-optimal for the firm to design contracts where the consumer can choose an intermediate level of privacy.     

Laser induced optoacoustic spectroscopy of benzil: Evaluation of structural volume change upon photoisomerization

The cis-skew to trans-planar photoisomerization of benzil in the photoexcited state was studied by laser-induced optoacoustic spectroscopy (LIOAS) in a series of normal alkane solvents at room temperature. The structural volume change due to the photoisomerization process has been estimated and compared with the same calculated from the optimized skew and trans structures. The magnitude of the structural volume change is estimated to be 22.9 ± 1.2 mL/mol. This study reveals that an expansion in volume occurs during the photoinduced isomerization process. In non-polar alkane solvents, the estimated volume change has been argued to be free from electrostrictional contribution.     

Ultrasonic and Thermophysical Properties of Cobalt Nanowires

Acoustical Physics - We have estimated elastic, mechanical, thermal and ultrasonic properties, in high temperature regime, of cobalt nanowires (Co-NWs) having a hexagonal close-packed (HCP)...     

Prediction and simulation of wear response of Linz–Donawitz (LD) slag filled glass–epoxy composites using neural computation

This article reports on the implementation of a soft computing technique based on artificial neural networks (ANNs) in analyzing the wear performance of a new class of hybrid composites filled with Linz–Donawitz slag (LDS). LDS is a major solid waste generated in huge quantities during steel making. It comes from slag formers such as burned lime/dolomite and from oxidizing of silica, iron etc. while refining the iron into steel in the LD furnace. In this work, hybrid composites consisting of short glass fiber (SGF) reinforced epoxy filled with different LDS content (0, 7.5, 15 and 22.5 wt%) are prepared by simple hand lay‐up technique. Solid particle erosion trials, as per ASTM G 76 test standards, are conducted on the composite samples following a well‐planned experimental schedule based on Taguchi design of experiments. Significant process parameters predominantly influencing the rate of erosion are identified. The study reveals that the LDS content is the most significant among various factors influencing the wear rate of these composites. Further, a model based on ANN for the prediction of erosion performance of these composites is implemented. The ANN prediction profiles for the characteristic wear properties exhibit very good agreement with the measured results demonstrating that a well‐trained network has been created. The simulated results explaining the effect of significant process variables on the wear rate indicate that the trained neural network possesses enough generalization capability of predicting wear rate even beyond the experimental range. Copyright © 2014 John Wiley & Sons, Ltd.     

Asymmetric synthesis of 1-deoxyazasugars from chiral aziridines

A general and facile synthesis of enantiopure 1-deoxyazasugars was achieved from stereoselective dihydroxylation of a common synthetic intermediate, piperidine ring fused oxazolidin-2-one, originating from a commercially available starting substrate, chiral aziridine-2-carboxylate, in high yields.     

Pregnane and pregnane tetraglycoside from Marsdenia roylei

Pregnane oligoglycoside, namely roylinine, and a pregnane derivative, namely marsgenin, have been isolated from chloroform-soluble extract of dried stem of Marsdenia roylei, and their structures were determined using 1H-NMR, 13C-NMR, 1H-1H COSY, HSQC, TOCSY and FABMS spectral techniques as well as chemical degradation and derivatisation.