Synthesis and isolation of a monocyclic phosphorane with a P-C bond derived from chloral

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2876–2877, December, 1990.     

MLC Determination of Preservatives in Cranberry Foodstuffs

Optimized conditions for the determination of 14 food preservatives were selected by using interpretative optimization strategy and Derringer’s desirability function for combining three main chromatographic goals: resolution, separation time and ruggedness. The best mobile phase for separation by micellar liquid chromatography contains 0.045 M SDS and 1.0% (v/v) 1-pentanol at pH 2.5 adjusted with trichloroacetic acid. The accuracy of the method was confirmed by analysis of spiked samples and is useful for routine analysis of food preservatives in drinks due to simple sample preparation, safety and low cost of micellar mobile phases. Presented in part by A.P. Boichenko at the 4th Black Sea Basin Conference on Analytical Chemistry, 19–23 September, 2007, Sunny Beach, Bulgaria.     

Kinetics of the self reaction of cyclohexyl radicals

The kinetics of the self-reaction of cyclohexyl radicals was studied by laser photolysis/photoionization mass spectroscopy. Overall rate constants were obtained in direct real-time experiments in the temperature region 303-520 K and at bath gas (helium with up to 5% of radical precursors) densities (3.00-12.0) × 10(16) molecules cm(-3). Cyclohexyl radicals were produced by a combination of the 193 nm photolysis of oxalyl chloride ((CClO)(2)) with the subsequent fast reaction of Cl atoms with cyclohexane, and their initial concentrations were determined from real-time profiles of HCl. The observed overall c-C(6)H(11) + c-C(6)H(11) rate constants demonstrate negative temperature dependence, which can be described by the following expressions: k(1) = 4.8 × 10(-12) exp(+542 K/T) cm(3) molecule(-1) s(-1), with estimated uncertainty of 16% over the 303-520 K temperature range. The fraction of disproportionation equal to 41 ± 7% was determined at 305 K; analysis of earlier experimental determinations of the disproportionation-to-recombination branching ratio leads to recommending this room-temperature value for other temperatures. The corresponding temperature dependences of the recombination (1a, bicyclohexyl product) and the disproportionation (1b, cyclohexene and cyclohexane products) channels are k(1a) = 2.8 × 10(-12) exp(+542 K/T) and k(1b) = 2.0 × 10(-12) exp(+542 K/T) cm(3) molecule(-1) s(-1), with estimated uncertainties of 20% and 29%, respectively.     

Exogenous iron redistribution between brain and liver after administering <Superscript>57</Superscript>Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> ferrofluid to a rat brain ventricle

The natural excretion of ⁵⁷Fe enriched magnetic nanoparticles from a rat’s brain through its blood–brain barrier is studied. Dextran-coated iron oxide nanoparticles are transcranially injected into the rat’s brain ventricle. The injected nanoparticles undergo biotransformation into iron-containing proteins distributed over the brain tissues, while the exogenous iron transported from the brain to other organs is eliminated from the body over time.     

Reactions of 4-chloro-6-oxo-2,3-dihydro-5-azabenzofurans with amines

The reaction of 7-nitro- and 7-unsubstituted 4-chloro-6-oxo-2,3-dihydro-5-azabenzofurans with primary and secondary amines proceeds with substitution of the chlorine atoms by amine residues and with recyclization of the compounds to 5- and 7-azaindoline derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No, 10, pp. 1311–1313, October, 1973.We thank Yu. N. Sheinker, E. M. Peresleni, L. M. Alekseeva, N. A. Zosimova, and Yu. I. Pomerantsev for their assistance in conducting the spectral investigations.     

The oxidation state of manganese in its oxides and some other compounds,from the fine structure of the Kβ1β′-lines

Summary The X-ray K₁-emission spectra of the lower oxides of Mn have been studied. From this study it is concluded that Mn is present in the bi-, ter- and quadrivalent states in the oxides of apparently tervalent manganese, in approximately equal proportions.

---

Zusammenfassung Aus den KK₁-Linien der Röntgenemissionsspektren der niederen Manganoxide ergibt sich, daß das Mn in den Oxiden seiner scheinbar dreiwertigen Form in annähernd gleichen Mengenverhältnissen als Mn(II), Mn(III) und Mn(IV) vorliegt.

     

Reactions ofβ-chloroethyl derivatives of tricoordinated phosphorus acids with 1-nitro-1-propene

Conclusions The reactions of the-chloroethyl derivatives of trivalent phosphorus acids proceed via an ionic intermediate, which, depending on the experimental conditions, is stabilized in the direction of ring closure to give an adduct with a pentacovalent phosphorus atom and the formation of the corresponding unsaturated and (-methyl--nitroethyl)phosphoryl compounds. The liberated-chloroethyl nitrite functions as an oxidizing agent of the starting-chloroethyl derivatives of trivalent phosphorus acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1398–1401, June, 1978.The authors thank É. I. Gol'dfarb for taking the³¹P–{¹H} NMDR spectra.     

Use of Fullerite (C60/C70) as Modifier of Epoxy-4,4'-Isopropylidenediphenol Oligomers

The use of fullerite as modifier of ED-20 epoxy-4,4'-isopropylidenediphenol oligomer cured with polyethylenepolyamine was considered. Interaction of fullerite with the polymer was evaluated. The effect of fullerite on combustion and heat resistance of the epoxy compound and on formation of the three-dimensional network structure was determined.     

Limit of Detection in Test Methods of Analysis with Visual Indication: Affecting Factors

A statistical approach to evaluating the limit of detection (c_min) was used for studying 12 test systems with visual indication based on reagent indicator paper, polyurethane foam, gelatin films, powdered methylsilicic acid, and reagent solutions. It was proposed to characterize the quality of test systems by relative width of the region of an unreliable response. The dependence of the characteristics of test systems on the material of the support, the type of analytical reaction, the conditions of color observation in the test system, and the number of observations were discussed.