Oxidation of magnesium with cyclopentadienyl(triphenylphosphine)nickel chloride in aprotic solvents

The products of magnesium oxidation with cyclopentadienyl(triphenylphosphine)nickel chloride were revealed. Effective equilibrium constants of adsorption of the reagents on the metal surface, entropy and enthalpy of these processes, rate constants, and activation energy were determined. A probable scheme of the process is assumed.     

Capillary electrophoresis determination of nitrate and nitrite in high-salt perchlorate solutions for the UC dissolution study

The capillary electrophoresis method with direct UV detection is proposed for the determination of nitrite and nitrate in high-salt perchlorate solutions issued from uranium carbide dissolution. The isotachophoretic sample stacking was used to compensate for the perchlorate matrix interference. Simple electrolyte composed of 120 mM formiate buffer, pH 3.8 enabled the nitrate and nitrite determination in the presence of up to 1000-fold excess of perchlorate with 2 μM and 4 μM detection limits for nitrate and nitrite, respectively. The proposed method was applied to the determination of nitrate and nitrite in high-salt non-irradiated uranium carbide dissolution samples.     

Polarization of nondegenerate nonrelativistic neutron gas particles by a magnetic field

The occupation of energy subbands with the magnetic moments parallel and antiparallel to the direction of the magnetic field for a nondegenerate neutron system of a specified concentration is calculated in the framework of the statistical thermodynamics of equilibrium systems. The kinetic neutron energies for the two subbands as well as the total system energy with allowance made for Pauli paramagnetism are determined. Byelorussian State University, Brest State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 39–43, April, 2000.     

Entropy criterion for the life span of load-carrying technical-grade rubber parts

A model of local breakdown is proposed for calculating the life span of load-carrying technical-grade rubber parts, based on the thermodynamics of irreversible processes and on the entropy criterion of breakdown. The entropy hypothesis has been proved experimentally, and the numerical value of the critical specific entropy has been obtained for grade IRP-1347 rubber, this value being constant for a given material.     

Oxidation of magnesium with diphenylbismuth and diphenylantimony chlorides in polar solvents

The intermediate and final products of the reactions of magnesium with diphenylantimony and diphenylbismuth chlorides were identified, and the formal kinetic relationships of the process were elucidated. The apparent equilibrium constants, enthalpies, and entropies of adsorption of the reagents on the metal surface, and also the rate constants and activation energies of the reactions in dimethylformamide-p-xylene mixture were determined. Probable schemes of magnesium oxidation with the organobismuth and organoantimony chlorides were considered.     

Metal Complexes of Mesitylphosphine: Synthesis, Structure, and Spectroscopy

A series of primary phosphine homoleptic complexes [ML(4)](n)()(+)X(n)() (1, M = Ni, n = 0; 2, M = Pd, n = 2, X = BF(4); 3, M = Cu, n = 1, X = PF(6); 4, M = Ag, n = 1, X = BF(4); L = PH(2)Mes, Mes = 2,4,6-Me(3)C(6)H(2)] was prepared from mesitylphosphine and Ni(COD)(2), [Pd(NCMe)(4)][BF(4)](2), [Cu(NCMe)(4)]PF(6), and AgBF(4), respectively. Reactions of 1-4 with MeC(CH(2)PPh(2))(3) (triphos) or [P(CH(2)CH(2)PPh(2))(3)] (tetraphos) afforded the derivatives [M(L')L](n)()(+)X(n)() (L' = triphos; 6, M = Ni, n = 0; 7, M = Cu, n = 1, X = PF(6); 8, M = Ag, n = 1, X = BF(4); L' = tetraphos; 9, M = Pd, n = 2, X = BF(4)). Addition of NOBF(4) to 1 yielded the nitrosyl compound [NiL(3)(NO)]BF(4), 5. The solution structure and dynamics of 1-9 were studied by (31)P NMR spectroscopy (including the first reported analyses of a 12-spin system for 1-2). Complexes 1, 3, 6, and 7.solvent were characterized crystallographically. The structural and spectroscopic studies suggest that the coordination properties of L are dominated by its relatively small cone angle and that the basicity of L is comparable to that of more commonly used tertiary phosphines.     

Inertness of C<Subscript>60</Subscript> fullerene toward RO<Subscript>2</Subscript><Superscript>·</Superscript> peroxy radicals

The reactivity of fullerene C₆₀ toward peroxy radicals RO₂ ^· was tested by the chemiluminescence method. A comparison of the influence of C₆₀ and known inhibitors on the kinetics of liquid-phase chemiluminescence (CL) during oxidation of a series of hydrocarbons (ethyl-benzene, cyclohexane, n-dodecane, and oleic acid) shows that the fullerene does not react with the RO₂ ^· radicals. A sharp decrease in the CL intensity observed upon C₆₀ addition is caused by the quenching of CL emitters with fullerene but not by inhibition of hydrocarbon oxidation. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1808–1811, August, 2005.     

Tin oxidation with 3,6-di-tert-butyl-o-benzoquinone

The kinetics of tin oxidation with 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) in toluene was studied. The scheme of formation of tin o-quinone complexes during metal oxidation with 3,6-Q in different aprotic solvents was suggested on the basis of the kinetic, EPR, and IR data.