Kinetics of oxidation of isopropanol by IO4? catalyzed by metal ions

The kinetics of oxidation of isopropanol (IPA) by IO ₄ ^– in the presence of Os(VIII), Ru(III) and mixture of Os(VIII) and Ru(III) has been studied. The catalytic effect was found to be in the order Os(VIII)

IO ₄ ^– Os(VIII), Ru(III) Os(VIII) Ru(III), . : Os(VIII)     

Phase transitions in thallous nitrate. A reinvestigation

A detailed reinvestigation of the phase transitions in thallous nitrate using DSC, X-ray, IR and optical microscopy has been undertaken. The DSC measurements on anhydrous samples show that the orthorhombic [OR] → hexagonal [HEX] transition sets in at 349 ± 1 K and peaks around 353 K. However, its intensity depends upon several factors such as particle size, moisture content and thermal history of the sample. The HEX→cubic [C] transition sets in around 405 K and shows two peaks at ～409 K and 413 K. Their relative intensities depend on the moisture content and thermal history of the sample. On cooling, the peaks show hysteresis and, by selective thermal cycling, the pairs of transitions, which correspond to the same process during heating and cooling, have been identified. IR spectra recorded in the OR and HEX phases at room temperature show that the symmetric stretching frequency (～1040 cm^?1) of the nitrate ion gets damped in the HEX phase. X-ray and optical microscopy data are in good agreement with the DSC observations.     

Oxygen promoted radical polymerization of acrylonitrile in aqueous nitric acid. A kinetic study

The polymerization of acrylonitrile (AN) initiated by oxygen-ascorbic acid (AA)-ferric ion system was studied in dil. HNO₃ at 40°. The rate of polymerization, R_p, was found gravimetrically. In the [Fe³⁺] range, (2–5 × 10^?5 M, R_p was proportional to [AN]^{1.5 ± 0.05}, [O₂]^{0.5 ± 0.02} [AA]⁰ and [Fe³⁺]⁰; for [Fe³⁺] = (5–30) × 10^?5 M, it was proportional to [AN]^{1.8 ± 0.05}, [O₂]^{0.6 ± 0.02}, [AA]⁰ and [Fe³⁺]^{?0.9 ± 0.05}. A plausible reaction scheme is proposed and rate law presented to explain these results. R_p increased with ionic strength and [HNO₃] (up to ～0.25 M). An initial rate increase with temperature followed by a decrease was noticed. Chain lengths of the polymers were determined viscometrically.     

PHOTOREDUCTION OF SOME NITROBIPHENYL ETHER HERBICIDES TO NITRO RADICAL ANIONS BY β-CAROTENE AND RELATED COMPOUNDS

Abstract —The nitrobiphenyl ether herbicides; 4-nitrobiphenyl ether, bifenox, nitrofen, acifluorfen, acifluorfen-methyl, acifluorfen-ethyl, and oxyfluorfen were reduced to their corresponding nitro radical anions by visible light in the presence of β-carotene, lycopene, retinol, retinal, retinoic acid and retinyl acetate in anaerobic solutions at high pH. It was more difficult to obtain spectra of bifenox, nitrofen and oxyfluorfen than acifluorfen derivatives, probably due to their poor solubilities. In neutral solutions the steady-state concentration of the nitro radical anions was low due to their faster rate of dispropor-tionation and the poor solubility of β-carotene. In the presence of retinal, the nitro radical anion of acifluorfen was produced at pH 7.4. Compounds containing conjugated double bonds such as crotonaldehyde and 2.4-hexadienal also reduced acifluorfen and its derivatives to their respective nitro radical anions in the presence of light. Ubiquinone-50 which does not contain conjugated double bonds in the side chain did not reduce acifluorfen under similar conditions.     

Stabilization of γ-sterilized biomedical polyolefins by synergistic mixtures of oligomeric stabilizers

The stabilization of polyolefins against γ-sterilization has been studied with single or binary additive system. The present attempt is to utilize synergistic mixtures of stabilizers which are approved for food contact applications. Ethylene-propylene (EP) copolymer has been melt-mixed with hindered amine stabilizers (HAS), phenolic antioxidants and organo-phosphites (hydroperoxide decomposer). Samples were sterilized with different doses of γ-radiation. Stabilization was characterized in terms of changes in the functional groups (oxidation products), tensile properties, yellowing and surface morphology by FTIR spectroscopy, Instron, colorimetry (reflectance) and scanning electron microscopy (SEM), respectively. Results were discussed by comparing the stabilizing efficiency of mixtures with and without phenol system. Among phenol containing systems, where we mostly observe discoloration due to the oxidation of hindered phenol and the combination of secondary HAS, tertiary HAS, organo-phosphite and hindered phenol exhibited improved stabilization efficiency than single or binary additive systems. The mixture of secondary HAS and tertiary HAS, has shown antagonistic effect of stabilization whereas their combination with organo-phosphite has exhibited synergistic effect of stabilization even at higher doses of γ-sterilization. The effects have been explained through the interaction between the stabilizers.     

Itinerant electron ferromagnetism in Sr2+-, Ca2+-, and Ba2+-doped rare-earth orthocobaltites (Ln3+1−xM2+xCoO3)

Electronic and magnetic properties of Ln_1?xSr_xCoO₃ (Ln = Pr, Nd, Sm, Eu, and Gd) systems show that above a critical value of x, the d electrons become itinerant while the materials become ferromagnetic at low temperatures. The ferromagnetic component increases with increase in x and decrease in temperature. The Curie temperature increases with x and decreases with decrease in the size of the rare-earth ion. Incorporation of Ba²⁺ in LaCoO₃ favors itinerant electron ferromagnetism relative to Sr²⁺ while Ca²⁺ is less favorable than Sr²⁺.     

Liquid structure of vanadium tetrachloride from neutron diffraction study

Assuming the separation of the intermolecular scattering function into the radial and angular parts and using Egelstaffet al’s orientational model for tetrachlorides, the structure of liquid vanadium tetrachloride has been studied. It has been observed that such a separation is approximate for this liquid and the introduction of a third correction term is required to account for the molecular structure function. The chlorine-chlorine partial structure and effective angleaveraged intermolecular chlorine-chlorine potential in the liquid has been evaluated. Without taking the third correction term, introduced to generate theoretically the molecular structure function, the centre structure function has been obtained in an approximate way from the experimentally observed molecular structure function and from it the centre radial distribution function, centre direct correlation function and the angle-averaged vanadium-vanadium effective potential has been evaluated.     

The gene-protein database of Escherichia coli: edition 5.

The gene-protein database of Escherichia coli is both an index relating a gene to its protein product on two-dimensional gels, and a catalog of information about the function, regulation, and genetics of individual proteins obtained from two-dimensional gel analysis or collated from the literature. Edition 5 has 102 new entries--a 15% increase in the number of annotated two-dimensional gel spots. The large increase in this edition was accomplished in part by the use of a new method for expression analysis of ordered segments of the E. coli genome, which has resulted in linking 50 gel spots to their genes (or open reading frames) and another 45 to specific regions of the chromosome awaiting the availability of DNA sequence information. Communication of information from the scientific community resulted in additional identifications and regulatory information. To increase accessibility of the database it has been placed in the repository at the National Center for Biotechnology Information (NCBI) at the National Library of Medicine under the name ECO2DBASE. It will be updated twice yearly. This edition of the gene-protein database is estimated to contain entries for one-sixth of the protein-encoding genes of E. coli.     

Growth of hair and the trace element profile a study by sectional analysis

Correlations between the growth of hair and the trace element profile have been investigated by non-destructive neuron activation analysis through gamma-ray speetrometry using NaI(Tl) as well as Ge(Li) detectors. After preliminary investigations to establish the experimental errors, the effect of washing procedures and in-person variations, hair samples belonging to ladies with known case histories, particularly with regard to dietary habits, health and profession, were examined. Scalp-hair samplex 50–100 cm in length, representing an average time span of ∼5–10 years were collected by combing. Samples in their non-anagen phase, differentiated by their roots, were analysed in 10 cm sections. The concentrations of the following elements were determined: Na, Cl, Mn, Co, Cu, Zn, As, Se, Ag, I, Au and Hg. Absolute values for the concentrations are reported for most of the elements, while for the rest relative values for the various sections are given. The values for the different sections vary by large factors for many elements although for some elements, like Cu and Mn, the variations are not appreciable. The unusually large concentrations of elements like Se ang Hg are in broad agreement with the case histories. However, detailed examination of the results with regard to time-dependent variations seem to pose serious problems in the applications to forensic science.     

Isopoly-molybdic acids

From the measurements of conductivity, diffusion coefficient etc., Jander indicated the presence of several isopoly-anions of molybdenum under different pH conditions. He and subsequent workers in the field dealt with solutions only. In the present work one free molybdic acid, and one ammonium acid molybdate were isolated in solid condition at pH 4.6 and 2. On analysis, their compositions were found to be H₄Mo₃O₁₁ and NH₄H₅Mo₆O₂₁ (or (NH₄)₂H₄Mo₇O₂₄) respectively.