Effect of Rheological Properties of the Dispersion Medium on Separation of Suspensions in Hydrocyclones with Various Working Space Configurations

The model of separation of suspensions with a non-Newtonian dispersion medium in a cylindroconical hydrocyclone, which takes into account the effect of the Coriolis force on solid particles, was constructed and applied to analysis of the rheological properties of the dispersion medium on separation of suspensions in hydrocyclones with various working space configurations.     

Spectrochemical determination of lithium,sodium, potassium and rubidium in rocks and minerals using the stallwood jet

A D C, spectrochemical method using the STALLWOOD jet has been developed for the determination of Li, Na, K and Rb in silicate minerals and rocks. Samples are mixed with graphite and Cs₂CO₃ in tho ratio 2 : 1 : 1, and Cs serves as internal standard. Precision and accuracy is satisfactory.     

Effect of Peptization on Texture and Physicomechanical Properties of Aluminum Hydroxides

The method of low-temperature adsorption of nitrogen was applied to study structural characteristics of commercial peptized aluminum hydroxides. An increase or decrease in the porometric volume, depending on the nature and concentration of the peptizing agent, was analyzed. The phenomena observed are explained in terms of the mechanism suggested for formation of the pore system in commercial aluminum hydroxides. The dependence of the physicomechanical properties of active aluminum oxide on synthesis conditions and texture characteristics of commercial aluminum hydroxides was studied.     

Application of the chemiluminescence systems to evaluate the role of Fcgamma and complement receptors in stimulating the oxidative burst in neutrophils

We have established a luminol- and a lucigenin-dependent CL methods to investigate the role of the receptors for Fc portion of IgG (FcgammaR) and/or complement receptors (CR) in mediating the oxidative burst in neutrophils from systemic lupus erythematosus (SLE) patients compared with healthy controls. In the luminol-CL system, all the reactive oxygen species (ROS) are responsible for light production, whereas in the lucigenin-CL system, only the first ROS generated, converts the lucigenin into an unstable intermediate molecule, which also emits light. First, neutrophils from healthy controls and SLE patients were stimulated with different IC opsonized or not with complement from normal human serum (NHS) or SLE serum, in presence of 10(-4) M luminol. This method was able to differentiate the role of the FcgammaR, CR and FcgammaR/CR co-operation in mediating the oxidative burst, as well as show that the oxidative burst mediated by these receptors was reduced in neutrophils from SLE patients. Second, neutrophils from healthy controls and SLE patients were stimulated with different IC, opsonized or not with NHS, in presence of 10(-3) M lucigenin. In this case, the lucigenin-CL system was also able to differentiate the role of FcgammaR and FcgammaR/CR co-operation, as well as show differences among healthy controls and two different groups of SLE patients according to their clinical manifestations. In conclusion, we have established two sensitive CL systems to study the role of FcgammaR and/or CR in stimulating the oxidative burst of neutrophils, which can be applied in monitoring the involvement of these receptors in the immunopathogenesis of SLE.     

Pyrimidines

The corresponding 2-pyrimidoylacetate esters (I, II) and 2-pyrimidoyl-acetonitrile (V) were obtained by condensation of pyrimidine-2-carboxylic acid esters with methyl acetate or acetonitrile. The structures of the tautomeric forms were determined by IR and PMR spectroscopy. The effect of a solvent and protonation of the pyrimidine ring on the ketone-enol equilibrium was examined.     

Properties of molten carboxylates part 6. A quantiative differential thermal analysis study of phase transitions in some zinc and cadmium carboxylates

Quantitative DTA results are presented for the phase changes in some cadmium and zinc n-alkanoates. Cadmium carboxylates form liquid crystal phases. The total entropy of the solid-to-liquid transition is small indicating a high degree of aggregation in the isotropic liquid. The phases previously reported by Skoulios are shown to be due to the presence of basic carboxylates. The zinc carboxylates have solid—solid transformations but do not form liquid crystal phases. The entropies of fusion are of the same order as those in the lead salts showing only a small degree of aggregation in the liquid.     

Synthesen mit Nitrilen, 29. Mitt.: Die linearen Kondensationsprodukte aus Dimethylaminophenylpropenon und Malonsäuredinitril

Zusammenfassung In unpolaren Lösungsmitteln kondensieren sich monomeres und dimeres Malonitril mit Dimethylamino-phenyl-propenon zu linearen Dienen bzw. Trienen. 2-Cyan-5-dimethylamino-3-phenyl-2,4-pentadienamid (4) kann als Zwischenprodukt für die Bildung von Pyridonen aus Enaminoketonen und Cyanacetamid aufgefaßt werden, da in saurem Medium die Cyclisierung zum 2-Oxo-4-phenyl-1,2-dihydro-pyridin-3-carbonitril bzw. dem Carbonsäureamid gelingt.

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Syntheses with nitriles, XXIX: The linear condensation products from dimethylaminophenyl propenone with malononitrile

Monomeric and dimeric malononitrile condense in nonpolar solvents with dimethylamino phenyl propenone to form linear dienes and trienes, resp. 2-Cyano-5-dimethylamino-3-phenyl-2,4-pentadienamide (4) represents an intermediate in the formation of pyridones from enamine ketones and cyanoacetamide. It is cyclised in acidic medium to 2-oxo-4-phenyl-1,2-dihydropyridine-3-carbonitrile (8) (or-3-carboxamide,9).

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Herrn Prof.O. Hromatka zum 65. Geburtstag gewidmet.     

Chemical properties of ylidene derivatives of azines. 3. Synthesis and reactions of ylidene derivatives of halopyrimidines

Some dihydropyrimidines have been obtained which contain a cyanoacetic ester or malononitrile residue and chlorine in positions, 2, 4, and 6. The reactions of these compounds with nucleophiles has been examined.For communication 2, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 963–969, July, 1986.     

Reactions of 1,2,4-Triazines with Nucleophiles. 6. Use of SNH Methodology for the Direct Introduction of Cyclic Diketone Residue into the 1,2,4-Triazine Ring FORENAME = D. N.

3-R-6-Phenyl-1,2,4-triazine 4-oxides react with cyclic -diketones (dimethylbarbituric acid, dimedone, and indan) in both acidic (substrate activation) and basic conditions (nucleophile activation) with formation of ^H-adducts, intermediates in the nucleophilic substitution of hydrogen (S_N ^H) in 3-R-5-Nu-4-hydroxy-6-phenyl-4,5-dihydro-1,2,4-triazines. Oxidative aromatisation of these intermediates or auto-aromatisation of acylated (benzoyl chloride) at the NOH -adducts with elimination of benzoic acid gave the corresponding substituted 1,2,4-triazine 4-oxides or 1,2,4-triazines.     

Analysis of the terphenyls by a compressed pellet infrared method involving micro-distillation

A quantitative compressed pellet infrared method used together with a micro-distillation to effect separation of the isomer has been developed and reported here for the analysis of ortho-, meta-, and para-terphonyl. The terphenyl content is determined on fractions isolated by distillation from radiation damaged samples. The compressed pellet infrared method is preferred instead of the more conventional solution technique since smaller quantities of isolated terphcnyl are required. The pellet method is applicable also to polyphenyls higher than the terphenyls. The solution technique is not due to the insolubility of the polyphenyls. It is expected that the compressed pellet spectral method developed here might well find application in the analysis of compounds other than polyphenyls. Results presented here appear to be the, first quantitative infrared data reported in the literaturu on polyphenyl compounds.