Low temperature synthesis and characterization of Mn3O4 nanoparticles

Heating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn₃O₄ nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements confirm a typical Mn²⁺signal with a highly resolved hyperfine structure.      

Influence of complexation on the composition of equilibrium phases in the system of Ce2(SO4)3-La2(SO4)3

The cocrystallization of Ce₂(SO₄)₃ and La₂(SO₄)₃ is studied in aqueous and H₂SO₄ (150 g/dm³) solutions at 25 °C and 64 °C. The effect of the formation of inner sphere sulfate complexes of the type LnSO ₄ ⁺ in determining the composition of the equilibrium phases is revealed.      

Dopamine and iron mediated fragmentation of galactocerebroside and cardiolipin in micelles

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and thin-layer chromatography (TLC) have been used to study dopamine and iron mediated free-radical transformation of lipids in their hydrophilic parts. It has been shown that the action of the dopamine/Fe²⁺ system on galactocerebroside or cardiolipin, which are the components of mixed micelles, results in formation of ceramide or phosphatidic acid and phosphatidylhydroxyacetone, respectively. These data, when combined with results obtained using the ascorbate/Fe²⁺/H₂O₂ oxidizing system with the same substrates, demonstrate that the formation of these products proceeds via an OH-radical induced fragmentation taking place in polar moiety of the starting lipids.      

Thermal synthesis and characterization of Al χ La1-χ P3O9

New binary lanthanum-aluminum triphosphates were synthesized by thermal-condensation method from H₃PO₄, La₂O₃ and Al(OH)₃. These pigments could be potentially used as special inorganic pigments; their corrosion-inhibition properties were widely studied. Synthesis conditions were determined on the basis of DTA and TG measurements. The products were also characterized by X-ray diffraction analysis. Physical properties — density by pycnometric method, particle size distribution, oil number and critical pigment volume concentration (CPVC), pH and specific conductivity of their aqueous extracts were also determined.      

Preparation and shape control of β-Ni(OH)<Subscript>2</Subscript> nano-particle

A simple and convenient method for the preparation of needle-shape nanoparticles of β-Ni(OH)₂ has been developed. Results show that a needle-shaped β-Ni(OH)₂ can be easily obtained in the presence of ethylenediamine and sodium dodecylbenzene sulfonate within a size from 100 to 200 nm. The shape and structure of the product were characterized by XRD, TEM and FT-IR. It is noteworthy that the formation of needle-shape β-Ni(OH)₂ benefits from the addition of sodium dodecylbenzene sulfonate. The optimum preparation conditions and the possible mechanism are also discussed.      

Indirect determination of lutetium by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode

Lutetium has been determined by differential pulse anodic stripping voltammetry in an acidic solution containing Zn-EDTA. Lutetium (III) ions liberated zinc (II), which was preconcentrated on a hanging mercury drop electrode and stripped anodically, resulting in peak current linearly dependent on lutetium (III) concentration. Less than 0.4 ng mL⁻¹ lutetium could be detected after a 2 min deposition.      

Electrospinning of the hydrophilic poly (2-hydroxyethyl methacrylate) and its copolymers with 2-ethoxyethyl methacrylate

The goal was to electrospin 2-hydroxyethyl methacrylate — based biocompatible polymers and prepare submicron fibres (nanofibers) for biomedicinal applications. Syntheses of poly(2-hydroxyethyl methacrylate) (HEMA) and its copolymer with 2-ethoxyethyl methacrylate (EOEMA), and their characterization by viscometry and molecular weight are described. Their relation to electrospinning is discussed. Electrospinning of HEMA homopolymer from water-ethanol is successful for molecular weights 6.31 × 10⁵ and 1.80 × 10⁶ g/mol. Electrospinning of HEMA/EOEMA copolymers is feasible from ethanol.      

Removal of uranyl ions from UO2(NO3)2 solution by means of Chlorella vulgaris and Dunaliella salina algae

This paper deals with a study of the biosorption of UO₂ ²⁺ ions on two green algae: Chlorella vulgaris and Dunaliella salina. By investigating the retention degree versus contact time from Langmuir and Freundlich biosorption isotherms, kinetic investigations and FTIR spectra it was found that the biosorption process was greater for Chlorella vulgaris than for Dunaliella salina. A new kinetics method is proposed to establish the reaction order concerning the biosorption process of uranyl ions on these biomasses.      

Alkylation of ambident indole anion in ionic liquids

Alkylation of indole salts in different ionic liquids is reported. Ionic liquids increase the alkylation reaction rate of ambident indole anion and reduce the effects of counter ions and/or additives, the alkylation reaction rates being independent of the presence of small amounts of protic solvents or water.      

Ionic liquid-functionalized SBA-15 mesoporous material: efficient heterogeneous catalyst in versatile organic reactions

Ionic liquid-functionalized mesoporous materials exhibited high catalytic activity in versatile organic reactions, such as cycloaddition of carbon dioxide (CO₂) with epoxide, aza-Michael addition of amines to α, β-unsaturated carbonyl compounds, and the Biginelli reaction of aldehyde, ethyl acetoacetate and urea. Recycling of the catalyst in these reactions could be carried out and the catalyst used at least five times without significant loss in activity.      

Synthesis and pharmacological properties of 3-(2-methyl-furan-3-yl)-4-substituted-Δ<Superscript>2</Superscript>-1,2,4-triazoline-5-thiones

By the reaction of 2-methyl-furan-3-carboxylic acid hydrazide with isothiocyanates, 1-[(2-methyl-furan-3-yl)carbonyl]-4-substituted thiosemicarbazides 1 were obtained. Further cyclization with 2% NaOH led to the formation of 3-(2-methyl-furan-3-yl)-4-substituted-Δ²-1,2,4-triazoline-5-thiones 2. The pharmacological effects of 2 on the central nervous system in mice were investigated. Strong antinociceptive properties of the investigated derivatives were observed in a wide range of doses.      

Influence of the addition of Pd and Cu to cobalt catalysts prepared by SMAI for F-T synthesis

The Co-Pd/SiO₂ and Co-Cu/SiO₂ catalysts were prepared via solvated metal atom impregnation (SMAI) method and investigated for the Fischer-Tropsch (F-T) synthesis. The catalysts contained 5wt.% Co and a weight ratio of Pd (or Cu) to Co of 1/30. XPS indicated that Co, Pd and Cu were in metallic state. The results of XPS and magnetic measurements showed that Co and Pd (Cu) were alloyed. The Co particles on the catalysts were very highly dispersed and they displayed superparamagnetic behavior. FT-IR indicated that the electrons shifted from Cu and Pd to Co. Catalytic tests showed that CO hydrogenation rates followed the order Pd-Co > Cu-Co > Co.      

Macrocyclic host cyclophosphazenes from aminolysis of N3P3CI6 by bis-(2-ortho-aminophenoxyethyl)ether

Aminolysis of N₃P₃CI₆ by an oxodiamine, bis-(2-ortho-aminophenoxyethyl) ether, has been carried out under various experimental conditions and new products with different architectures have been obtained. The reaction in diethyl ether when using a Na₂CO₃-water interface process gives the mono-BINO as major product. Reaction on Al₂O₃/KOH leads to the spirocyclic compound, while, when the reaction is carried out in toluene in the presence of NEt₃, a mixture of mono- and di-BINO products are obtained. These new products have been characterized by IR, ¹H and ³¹P NMR spectroscopy.      

Esterification of palmitic acid with epichlorohydrin on anion exchange resin catalyst

The esterification reaction of palmitic acid with epichlorohydrin catalyzed by an anionic macroporous resin was studied. Purolite A-500 resin proved to be a very effective catalyst in the synthesis of 3-chloro-2-hydroxypropyl palmitate. The effects of certain parameters such as speed of agitation, catalyst particle size, catalyst loading, temperature, initial molar ratio between reactants on the rate of reaction were studied. It was found that the overall rate is intrinsically kinetically controlled. The structure of synthesized ester was confirmed by FTIR and ¹H NMR analyses.      

Anomalously large kinetic isotope effect

Activated diffusion of water between macromolecules in swollen cellulose is accompanied by anomalously high kinetic isotope effects of oxygen. The separation factor of heavy-oxygen water (H₂ ¹⁸O /H₂ ¹⁶O) is thousands of permilles instead of tens of permilles according to modern Absolute Rate Theory. This anomalous separation under usual conditions is disguised by the opposing process of very fast equalization to equilibrium through water-filled cellulose pores. This process is quicker by approximately 3 orders of magnitude than diffusion through the cellulose body. As a consequence, this opposition-directed equalization virtually eliminates the results of isotope separation. To reveal this anomaly it is necessary to suppress equalization, which was the primary problem for both discovery of this anomaly and its investigation. The method of investigating the anomalous separation in cellulose was developed with suppression of this negative influence. Discussion of the theoretical nature of the anomalous kinetic isotope effect is presented. This theoretical study would probably permit the discovery and use for isotope separation of the anomalously high isotope effect for other chemical elements, in particular, for those heavier than oxygen.      

Pyrrole thin films deposited on paper by pulsed RF plasma

Attempts were made to plasma deposit an oriented π-conjugated polymer of pyrrole (Py) on paper surfaces in order to produce electrically conductive layers. The N/C atomic ratio of 0.13–0.24 was observed for all treatment conditions. This implies the nature of the deposition formed on the paper surface via pulsed plasma is different from that of pyrrole monomer. An increase in conductivity of all pyrrole-plasma treated papers was observed. The 50 W RF-power with 5 min plasma exposed paper sample shows 8.15 × 10⁻⁹ S·cm⁻¹ conductivity. The conductivity measurements indicated a plasma-enhanced ring-opening reaction mechanism of pyrrole.      

Synthesis and isomerism of hydrazones of 2-(5-thioxo-4,5-dihydro-1,3,4-thiadiazol-2-ylthio)acetohydrazide

New hydrazones of 2-(5-thioxo-4,5-dihydro-1,3,4-thiadiazol-2-ylthio)acetohydrazide have been obtained and the percentages of anti/syn - conformers were determined. Based on the analyses of ¹H NMR spectra, it was concluded that for hydrazones obtained from the 2- hydroxybenzaldehydes and 2’-hydroxycetophenones the ratio between the anti-and syn-conformers depends on the strength of intramolecular hydrogen bond (IMHB) between the nitrogen atom of the imino group and the proton of the 2-hydroxy group. It was shown that increase in IMHB strength results in stabilization of the anti-conformer in solution.      

Palladium-catalyzed amination of quinaldine-5-triflate

Palladium-catalyzed amination reactions of quinoline triflate and the effect of a Pd catalyst, its ligands, solvents, bases, and temperature were studied. This method facilitated an easier pathway for the preparation of aminoquinoline derivatives as potential precursors of new serotoninerg agents.      

Contact angles of protein black foam films under dynamic and equilibrium conditions

The contact angles of protein Newton black foam films from ALG (alpha-lactalbumin), BLG (beta-lactoglobulin) and BSA (bovine serum albumin) are measured here within. The measurements are carried out under dynamic and equilibrium conditions. For all proteins, a strong hystheresis effect of the contact angle is observed under dynamic conditions. An attempt is made to explain these results by the slow adsorption and desorption kinetics of the protein bilayers and by the dynamic structure and the rheology of the protein network forming the bubble walls. In addition, we propose a modification of the experimental device reported previously for contact angle measurements of large flat films in equilibrium. The advantages of this method are discussed in detail. Some shortcomings (precision, reproducibility) of this preliminary variant of the device in this initial stage of its application, do not allow one to draw reliable conclusions about the interactions of these films. Some improvements of the measurement quality are proposed.      

Preparation of SAMS-CMC-CS bipolar membrane and its application in electro-generating FeO 4 2−

The preparation of SAMS-CMC-CS bipolar membrane grafted onto CMC by SAMS was reported. The cross-section view of SAMS-CMC-CS BM were studied by SEM. FT-IR spectrum indicated that SAMS-CMC-CS BM contained-SO ₃ ⁻ ,-COO⁻ and −N=CHR functional groups. Compared with CMC-CS BM, SAMS-CMC-CS BM appears to have better mechanical strength and chemical stability in alkali solution at [OH⁻]≥9.5 mol/L, with a swelling of 55 %. The electrochemical properties of SAMS-CMC-CS BM were also studied. SAMS-CS-CMC BM not only effectively prevented FeO ₄ ²⁻ from diffusing into the cathode chamber, but also played an important role in the supply of OH⁻ consumed during the electro-generated FeO ₄ ²⁻ process.