Isomerization of alkylaromatic hydrocarbons on nickel-boron-alumina catalysts

The activity of alumina and silica-alumina modified with nickel and/or boron trifluoride etherate in the transformations of o-xylene and -methylnaphthalene in the presence of gaseous hydrogen has been measured. Dependence between the yields of isomerization reaction and the concentration of Brönsted acid centers on the surface of the catalysts investigated was observed.     

Kinetics of Reactions between Some Compounds from the Three-Component Silver -Oxygen -Sulfur System

Reaction between Ag₂O and SO₂ gives silver and Ag₂SO₄. Heating Ag₂O/Ag₂S mixtures comprising between 66.67 to 100.00 mol % of oxide, at forced flow of inert gas, gives only silver.     

Transfer hydrogenation of phenanthrene in the presence of boron modified alumina or silica-alumina

Reactions of phenanthrene with hydrogen donors carried out in the presence of boron trifluoride etherate modified catalysts: silica, alumina or silica-alumina have been studied. Di-, tetra- and octahydrophenanthrenes as well as some bicyclic hydrocarbons were the reactions products. Their yields were strongly influenced by hydrogen donor polarity.     

Heavy metals as stressing factors in the red wood ants (Formica polyctena) from industrially polluted forests

Relations between metal contaminations in social groups of ants from colonies of Formica polyctena, from 5 localities variously contaminated by industrial pollution, and their metabolic and detoxifying strategies have been investigated. Cd, Pb, Zn, Mn, Cu levels have been measured in social groups of workers and pupae throughout the season. Patterns of metabolic, transport and detoxifying enzymes have been assayed and phosphoadenine nucleotides and the energy charge (AEC) have been determined. The metal content is a measure of the level of contamination and has been the highest in foragers returning to the nest. Body burdens of Cd, Pb and Zn diminished progressively from the surface workers to those from the inner part of the hill. The concentration of total adenylates was slightly lower than stated in Finnish ants poisoned with Cd, but the AEC index was always above 0.8, with high variations between the social groups. Carboxylesterases showed a positive correlation of activity pattern with the metal load in foraging workers, with the highest value for cadmium load in ants from a locality in the middle of a pollution gradient. The pattern of superoxide dismutase activity has been site-dependent, but it did not correlate well with the metal load in workers.     

Coupling of Methanol and Isobutanol to Ethers over γ-Alumina Catalyst. Kinetic Studies

The kinetic of methanol (MeOH) and isobutanol (iBuOH) coupling to ethers has been studied. Catalytic tests were carried out in the gas phase in a fixed-bed flow microreactor, in the temperature range of 463-533 K, under atmospheric pressure, using -Al₂O₃ as the catalyst. The quasi-homogeneous model for the process was assumed. The reaction rates were described by simple kinetics.