László Vida

Microwave irradiation as an alternative to phase transfer catalysis in the liquid-solid phase, solvent-free C-alkylation of active methylene containing substrates

Simple CH-acidic compounds can be easily monoalkylated in solid-liquid phase in the absence of a phase transfer catalyst applying microwave under solvent-free conditions.

n-Octane reforming over modified catalysts: II. The role of Au, Ir and Pd

Abstract A Pt-Sn/γ-Al 2 O 3 catalyst was modified by gold, iridium and palladium using metal adsorption technique. The parent and the modified catalysts were tested in n -octane reforming under conditions close to industrial applications. The added gold and iridium slightly increased the activity of the parent catalyst and decreased the temperature dependence of the liquid yield. Less isoparaffin and more aromatic hydrocarbon was found in the liquid product of the modified catalysts than in the product of the reference catalyst, while the octane numbers were similar to the reference ones. The gold-modified catalyst produced almost identical C n distribution at both temperatures. On the palladium-modified catalyst the conversion, the liquid yield and the octane number is somewhat poorer than on the reference one. The product distribution is, however, favorable: the aromatic content decreased while the isoparaffin content increased.

A Laboratory Steam-Cracking Reactor to Characterize Raw Materials

A laboratory steam-cracking reactor was designed, built and tested in order to compare yields under different operating conditions. A typical industrial gasoline was used as feedstock to test the reactor. The design of the reactor was found appropriate to crack hydrocarbon feedstocks and the olefin yields follow the expected trends.

Reductive dehalogenation of 4-halogenomethyl azetidin-2-one derivatives. Synthesis of (4-oxo-azetidin-2-yl)acetonitriles

The stability of the β-lactam ring under reductive conditions was examined in order to find a selective method for the synthesis of (4-oxo-azetidin-2-yl)acetonitrile derivatives. Fifteen variously substituted 4-halogenomethyl-β-lactam derivatives were synthesised and dehalogenated by three reductive methods. It was found that both the substituents connected to the four-membered ring and to the halogenomethyl group, as well as the applied method have considerable influence on the ratio of the resulting ring-containing and ring-opened products. The best conditions have been defined to give – state products – in excellent yields.

Investigation of some α-amylases by high-performance hydrophobic-interaction chromatography

Abstract α-Amylases of different origins were investigated with a Synchropak propyl column and a linearly descending salt gradient in order to isolate the active fraction from among the inactive proteins present. Fractions collected by several injections were assayed for enzymatic activity by the modified Wohlgemut method. An experimental hydroxypropyl packing was tested for the separation of α-amylases under isocratic conditions, using a dilute buffer or plain water as eluent. The chromatograms obtained can serve as fingerprints for the quality control of some industrial proteins.

Suzuki-Miyaura Reaction of 4-Silyl-bromobenzenes with Phenylboronic Acid under Thermal and Microwave Conditions

The coupling reaction of phenylboronic acid with 4-silyl-bromobenzenes incorporating an ionic liquid support or its neutral analogue at 80 °C in DMF/H2O in the presence of Pd(PPh3)4 and Na2CO3 takes place much faster and more efficiently under microwave irradiation than under traditional heating. It is an attractive method to carry out the generally slow Suzuki-Miyaura reactions under microwave conditions.

Palladium as a Catalyst in a Polycondensed Matrix, Part 1

Adducts of palladium and organic amines were polycondensed. The catalysts formed were studied in liquid-phase hydrogenations of simple organic molecules. Their activities and specific selectivities were compared with these of a palladium/carbon catalyst.