The state of nickel in the silver modified NiMg/SiO<Subscript>2</Subscript> vegetable oil hydrogenation catalysts

Two series of silver modified Ni-Mg materials were synthesized by precipitation-deposition on SiO₂ support derived from two silica sources: diatomite activated at 800°C (Series a; Mg/Ni = 0.1 and SiO₂/Ni = 1.07) and synthetic water glass (Series b; Mg/Ni = 0.1 and SiO₂/Ni = 1.15). The modification with silver was made at three molar Ag/Ni ratios, namely 0.0025, 0.025, and 0.1. The effects of the source of the silica support and the silver presence and content on the nickel state in the silver modified reduced-passivated NiMg/SiO₂ precursors of the vegetable oil hydrogenation catalyst were established by X-ray diffraction and X-ray photoelectron spectroscopy techniques. The passivation procedure was applied in order to protect the metallic nickel particles from further oxidation. The crystallization of the formed nickel hydrosilicate phases depends on the source of the silica support, more expressed in the diatomite supported samples. It was shown that the silver modification of the NiMg/SiO₂ precursors enhances the reduction of the nickel hydrosilicates accompanied by formation of relatively smaller metallic nickel particles, more pronounced in the water glass supported precursors. The increase of the silver content in the water glass deposited samples is responsible for the metallic nickel dispersion increase. The higher content of the Ni⁰ particles on the surface of the diatomite deposited samples is in accordance with the higher stability of the larger metallic nickel crystallites to oxidation during the passivation step. On contrary, higher dispersed Ni⁰ particles on the surface of the water glass supported samples are more susceptible to the oxida The article is published in the original.     

Selective Reduction of ortho-Acylated β-Enaminones of Homoveratryamine and Their Cyclization to 1,2,3,4-Tetrahydroisoquinolines with β-Enaminone Moiety

Enaminones are very stable compounds and can be prepared from cheap and easily available starting materials. Therefore they are excellent starting materials in organic synthesis. The selective reduction of ortho-acylated β-enaminones under mild conditions, keeping the enaminone moiety intact, is reported. The appropriated conditions for cyclization of newly obtained hydroxienamides were found. Novel 1-substituted 1,2,3,4-tetrahydroisoquinolines with potential anticonvulsic activity were synthesized.     

Infinite Dimensional Geometric Properties of Real Interpolation Spaces

Estimates for the moduli of noncompact convexity of l_p-sums and real interpolation spaces for finite families of spaces are given. It is proved that such an interpolation preserves nearly uniform convexity and property (β).     

Non-isothermal kinetics of dehydration of some selenite hexahydrates

The kinetics of dehydration of Al₂(SeO₃)₃·6H₂O, Ga₂(SeO₃)₃·6H₂O and In₂(SeO₃)₃·6H₂O were studied under non-isothermal heating on a derivatograph. The method of Coats-Redfern was used with different kinetics models. The values of the kinetics parameters characterizing the process were calculated. The dependencies observed were interpreted according to the generalized perturbation theory of chemical reactivity. Kinetic compensation effect was found.     

The uniform convexity of the Edmunds-Triebel logarithmic spaces

We show how uniform convexity can be preserved in the logarithmic spaces A_θ(logA)_b,p. Estimates are given for the moduli of convexity of A_θ(logA)_b,p in terms of the moduli of A₀ and A₁, when one or both of them are uniformly convex.     

Solid dissolution in a thin liquid film on a horizontal rotating disk

A model for the rate of dissolution in liquid film on horizontal rotating disk is obtained by the method of Leveque. It as well as models found in the literature are subjected to experimental verification by dissolving disk cast of gypsum in two liquids. Satisfactory agreement with the model predictions is found. The rate with rotation is compared to that in gravitational film. Enhancements up to 2.5 times are established.     

Hydrogenation/Regioselective C‐Acylation Reaction of Diethyl Coumarin‐3‐phosphonate With NaBH4/Acid Anhydrides: A New One‐Pot Tandem Reaction

The one‐pot tandem reaction of diethyl coumarin‐3‐phosphonate 1 with a mixture of sodium borohydride/acid anhydrides gives mainly the corresponding hydrogenation/acylation product of diethyl 3‐acyl‐2‐oxochroman‐3‐ylphosphonates 3a–d in good yields. Different experimental conditions have been examined to get the best yields of the reaction products. From this reaction the hydrogenation product of diethyl 2‐oxochroman‐3‐ylphosphonate, 2, as well as the products of the consecutive hydrogenation, diethyl 2‐hydroxychroman‐3‐ylphosphonate (4) and diethyl 3‐[2‐hydroxyphenyl]‐1‐hydroxy‐propan‐2‐ylphosphonate (5), have been isolated.     

Chemical Structure and In Vitro Antitumor Activity of Rhamnolipids from Pseudomonas aeruginosa BN10

A newly isolated indigenous strain BN10 identified as Pseudomonas aeruginosa was found to produce glycolipid (i.e., rhamnolipid-type) biosurfactants. Two representative rhamnolipidic fractions, RL-1 and RL-2, were separated on silica gel columns and their chemical structure was elucidated by a combination of nuclear magnetic resonance and mass spectroscopy. Subsequently, their cytotoxic effect on cancer cell lines HL-60, BV-173, SKW-3, and JMSU-1 was investigated. RL-1 was superior in terms of potency, causing 50 % inhibition of cellular viability at lower concentrations, as compared to RL-2. Furthermore, the results from fluorescent staining analysis demonstrated that RL-1 inhibited proliferation of BV-173 pre-B human leukemia cells by induction of apoptotic cell death. These findings suggest that RL-1 could be of potential for application in biomedicine as a new and promising therapeutic agent.