In this article we finalize our experimental and theoretical studies on the (η2-C60)Pd(PPh3)2 palladium–phosphine fullerene complex. Full scale ab initio quantum-chemical calculations up to the B3LYP/SDDALL level of theory have been performed to determine the structure and electronic spectrum of (η2-C60)Pd(PPh3)2. Based on the results of calculations and experimental data we conclude that the preliminary interaction of the catalyst with the substrate facilitates the interaction of the substrate–catalyst complex with H2 by decreasing the energy barrier. In conclusions we summarize the results of our studies of the structure and electronic spectrum of the investigated complex, the kinetics of catalytic reactions, the influence of the solvents on the catalyst’s activity in the heterogeneous phase, and provide the possible mechanism of catalytic reaction. © 2004 Wiley Periodicals, reprinted with permission.
Extraction of biologically active substances is the main stage in the production of drugs from
natural compounds. With only a few exceptions, the process is performed by poorly efficient,
labor- and time-consuming (up to two weeks) methods based on percolation and maceration. In connection with this, intensification of the extraction stage, as well as increase in the final product quality, are tasks of special importance for the pharmaceutical industry. It was demonstrated that using various physical factors, including physical treatments (ultrasound, electrothermal processes, electroflotation, etc.), provides significant acceleration of the extraction process and a considerable decrease in the amount of structural metals used in the equipment and in the energy consumed in the process. The purpose of this work was to study the ultrasound-stimulated extraction of biologically active substances from raw plant materials and ways of acoustic energy dissipation in the system. © 2000 Springer, reprinted with permission.
FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to methods of hydrogenation of acetylene alcohols that are intermediate organic compounds used in pharmaceutical and perfume industry. Selective hydrogenation of acetylene alcohols to the corresponding ethylene alcohols is carried out with hydrogen at concentration of acetylene alcohol from 0.22 to 0.88 mole/l at 60-90 C using micellar palladium-containing catalyst at amount from 1.66 to 6.66 g/l. The catalyst is prepared by immobilization of palladium acetate on polystyrene- -poly-4-vinylpyridine block-copolymer by reduction of immobilized Pd(II) to Pd(0), applying of obtained palladium nanoparticles on aluminium oxide and treatment by ultrasonic oscillation at intensity 2.5-3 Wt/cm2, frequency 22 kHz for 1-4 min. EFFECT: improved method of hydrogenation, increased yield and effective rate of the synthesis.
Hydrogenation of triple bond of dehydrolinalool to double one of linalool was studied with Pd colloids prepared in polystyrene-poly-4-vinylpyridine micelles in toluene and deposited on Al2O3. The high selectivity (99.8%) of this catalyst is explained by durable modification of the Pd nanoparticle surface with 4-vinylpyridine units. The activity of Pd catalyst studied is determined by high reactivity of small Pd nanoparticles. The influence of solvent nature on catalytic properties of Pd colloidal catalyst is studied. Maximum relative rate was found to be in methanol, but the highest selectivity was achieved in toluene because the latter is a selective solvent for polystyrene-poly-4-vinylpyridine micelles and provides the better accessibility of reactive sites. © 1999 Elsevier, reprinted with permission.
Catalytic properties of Pd–fullerene complex η2-C60Pd(PPh3)2 have been studied in the hydrogenation of acetylenic alcohols. The kinetics of the homogeneous hydrogenation has been investigated under static conditions. The catalyst quantity and the initial concentration of acetylenic alcohol have been varied. Physico-chemical properties of Pd–fullerene complex have been studied using methods of NMR, IR- and UV-spectroscopies. Using experimental results and physico-chemical investigations, the mathematical model of the process and the reaction mechanism have been offered. © 1999 Elsevier, reprinted with permission.
FIELD: chemical technology. SUBSTANCE: linalool is produced from dehydrolinalool by selective hydrogenization on preliminary reduced palladium catalyst at increased temperature in hydrogen flow at concentration of dehydrolinalool 0.1-0.43 mole/l, at 40-70 C in the presence of heterogeneous catalyst made as a complex (η2-C60)Pd(PPh3)2, and applied on carbon carrier “Sibunit” at amount 0.05-0.3 g/l in inert medium. Linalool is an intermediate organic compound used in pharmaceutical and perfume industry. EFFECT: high purity of product, high rate of synthesis.
FIELD: extraction of valuable components from solids. SUBSTANCE: the method consists in preliminary grinding of vegetable raw material with a subsequent action by ultrasound at a frequency of 22 kHz and intensity of ultrasound action within 1 to 70 W/sq.cm for 60 to 420 s in a solution of ethanol. EFFECT: facilitated procedure.