Properties of Monocarboxy Cellulose Containing Sorbed Fe(III), Al(III), and Cr(III) Cations

Sorption of Fe(III), Al(III), and Cr(III) on monocarboxy cellulose at various pH, concentrations of metal chloride or sulfate in solution, and time was studied. The effect of type and amount of the cation sorbed on the physicomechanical properties, swelling, and stability in phosphate buffer of monocarboxy cellulose fibers was considered.     

Mass spectra of arylalkylpyridines

The basic principles of the mass-spectral fragmentation of arylalkylpyridines that contain substituents in various positions were established. The principle ions that can be used in Chromatographic mass-fragmentographic analysis in the study of liquid-crystal compositions were determined for each specific case.Communication 1 of the series Mass spectra of liquid crystalsTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1509–1513, November, 1987.     

Mössbauer study of hydrothermally-treated ferrosilica gels

Mössbauer spectroscopy and x-ray phase analysis have been used to examine the structural states and grain sizes of the iron-bearing phase in ferrosilica gels in the initial state and after hydrothermal treatment at 673 K. The component ratio has a substantial effect on the phase composition. The specific surface is also related to the phase composition.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 5, pp. 647–651, September–October, 1987.     

Structure and thermodynamics of hydrocarbon liquids: Computer simulation based on rism theory

A system of Ornstein-Zernike integral equations is solved numerically to determine the heats of vaporization ΔH_V of liquid ethane, propane, and n-butane. It is shown that the calculations (the deformations of valence bonds and bond angles in the liquid-phase molecules are ignored) give rather accurate values of ΔH_V, which are in agreement with the corresponding experimental data. On the other hand, it is established that if there are intramolecular rotational degrees of freedom, ΔH_V depends on the angle of internal rotation ϕ. The function ΔH_V(ϕ) is minimum for trans-conformations (ϕ=0) and maximum for cis-conformations (ϕ=180°). Hence, intermolecular interactions stabilize compact (convolute) conformations. The energy of this effect is of the order of 1 kJ/mole. Tver State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 5, pp. 808–813, September–October, 1995. Translated by I. Izvekova     

Short communication

The diffusion of copper, nickel and cobalt in silicon single crystals during irradiation with MeV protons, was studied under various experimental conditions. Under the irradiation normally used for charged-particle activation radiation enhanced diffusion negligible. The diffusion of radioisotopes caused by thermal effects however, lead to important errors. It is important to control the temperature of the irradiated samples.     

Course of bromination of thiazole and 2-methylthiazole

Bromination of thiazole by bromine in the presence of aluminum chloride in neutral solvent or without solvent takes place at the 2-position. Such an orientation contradicts the traditional addition-cleavage mechanism, and agrees with the ylid mechanism of electrophilic substitution. 2-Methylthiazole brominates at the 5-position, and the reaction is impeded in the presence of aluminum chloride; this is due to heterocycle deactivation by complexation with the Lewis acid at the nitrogen atom.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 837–840, June, 1986.