Influence of Mechanical Effects on the Hydrogen Peroxide Concentration in Aqueous Solutions

Physics of Wave Phenomena - An experiment has been performed, where water enriched in hydrogen peroxide was subjected to multiply dilution under mechanical action. It is established that, when the...     

Explosive Reduction of Graphite Oxide by Hydrazine Vapor at Room Temperature

Explosive reduction of graphite oxide aerogel at the moment of its contact with hydrazine vapor at room temperature was described. It was shown that the characteristics of the materials produced by explosive reduction of graphite oxide under thermal shock and under the action of hydrazine are virtually identical. This suggests the thermal nature of the explosion, which is initiated by an abrupt increase in the temperature of the surface of aerogel particles as a result of highly exothermic reactions of functional groups of graphite oxides with hydrazine. The composition and amount of gaseous products released at the moment of the explosive decomposition were estimated.     

Formation of organometallic complexes of platinum(II) and platinum(IV) in reactions of PtCl62− with alkanes,olefins and aromatics induced by γ-irradiation

γ- Irradiation of solutions of the ion PtCl₆^2? and n-hexane (or alkene) in MeCO₂H affords a π-olefin complex of platinum(II); σ-aryl complexes of platinum(IV) are formed in analogous reactions with aromatic compounds.     

Molecular structure of cybotactic nematics

Fizika Science and Engineering Cooperative Firm. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 3, pp. 119–125, May–June, 1992.     

Kinetics and mechanism of alkane hydroperoxidation with tert-butyl hydroperoxide catalysed by a vanadate anion

tert-Butyl hydroperoxide oxidizes alkanes in acetonitrile at 60 degrees C if the soluble vanadium(v) salt, n-Bu4NVO3, is used as a catalyst. Alkyl hydroperoxides are formed as main products which decompose during the course of the reaction to produce the more stable corresponding alcohols and ketones. Turnover numbers (ie. numbers of moles of products per one mole of a catalyst) attained 250. The kinetics and selectivity of the reaction have been studied. The mechanism proposed involves the formation of a complex between the V(V) species and t-BuOOH (K5 was estimated to be 5 dm3 mol(-1)) followed by decomposition of this complex (k6 = 0.2 s(-1)). The generated V(IV) species reacts with another t-BuOOH molecule to produce an active t-BuO* radical which attacks the hydrocarbon.     

A family of novel DNA sequencing instruments based on single-photon detection

We have developed a family of high-performance capillary DNA sequencing instruments based on a novel multicolor fluorescent detection technology. This technology is based on two technical innovations: the multilaser excitation of fluorescence of labeled DNA fragments and the "color-blind" single-photon detection of modulated fluorescence. Our machines employ modern digital and broadband techniques that are essential for achieving superior instrument performance. We discuss the design and testing results for several versions of the automated single lane DNA sequencers, as well as our approach to scaling up to multilane instruments.     

Oxidations by the system “hydrogen peroxide-[Mn2L2O3][PF6]2 (L = 1,4,7-trimethyl-1,4,7-triazacyclononane)-oxalic acid”. Part 6. Oxidation of methane and other alkanes and olefins in water

Oxidation of alkanes with hydrogen peroxide in water solution at 10-50 °C is efficiently catalyzed by the cationic dinuclear manganese (IV) derivative [Mn₂L₂O₃]²⁺ (1, with L = 1,4,7-trimethyl-1,4,7-triazacyclononane, TMTACN) in the form of the hexafluorophosphate salt ([1][PF₆]₂) if oxalic acid is present as a co-catalyst. Methane gives methanol and formaldehyde (turnover numbers, TONs, were 7 and 2, respectively, after reduction of the reaction mixture with ascorbic acid) whereas cyclohexane was oxidized with TONs up to 160 affording cyclohexyl hydroperoxide, cyclohexanone and cyclohexanol (the ketone was the main product, although at room temperature almost pure alkyl hydroperoxide was formed). In contrast to the oxidation in acetonitrile, the reaction with linear n-alkanes in water exhibits an unusual distribution of oxygenates. For example, in the oxidation of n-heptane the normalized reactivity of the methylene group in position 4 of the chain is 3-7 times higher than that of the CH₂ group in position 2. Dec-1-ene is epoxidized by hydrogen peroxide in water (a biphasic system) catalyzed by [1][PF₆]₂ and oxalic acid in the presence of a small amount of acetonitrile with TONs up to 1000 (no epoxidation has been detected in the absence of MeCN).     

Dynamic range of fluorescence detection and base-calling accuracy in DNA sequencer based on single-photon counting.

Recently, we developed a family of high-performance automated capillary DNA sequencing instruments based on a single-photon detection of fluorescently labeled DNA fragments. Our machines employ digital and broadband techniques, essential for achieving superior instrument sensitivity and dynamic range. In the present paper, we discuss limitations of the instrument's performance caused by the nonlinearity of single-photon detectors as well as methods for nonlinearity compensation which increase the detection dynamic range and base-calling accuracy.