JSCS Vol 62, No 1
J. Serb. Chem. Soc. 62(1) 1-17
Planar salting-out chromatography
TOMISLAV JANJIC, VUKOSAVA ZIVKOVIC-RADOVANOVIC and MILENKO CELAP
Faculty of Chemistry, University of Belgrade, P.O.Box 158, YU-11000 Belgrade, Yugoslavia
(Received 25 June 1996)
The method of planar salting-out chromatography is presented. The historical back-ground, the principle of the method, the sorbents and solvents used, as well as its resolution power are described. The mechanism of separating substances by this method, as well as various functional depences which exist between different chromatographic parameters, are discussed. Equations are derived proving the existence of a linear dependence between the logarithm of the separation factor and the mol per cent of ammonium sulphate in the solvent system, as well as between the logarithms of the separation factors of two pairs of substances being separated by the same series of solvents. Finally, a review of the application of the described method to date and the prospects of its development are given.
Key words: planar salting-out chromatography, review
Side chain liquid crystalline polyethers
NICOLAS SPASSKY, ANNE DELGADO, DANIEL TATON and CLAUDINE NOEL*
Chimie Macromoleculaire, URA 24 Universite Pierre et Marie Curie,
4 place Jussieu - 75259 Paris Cedex 05 and
*Laboratoire de Phisico-Chemie Structurale et macromoleculare, URA 278, Ecole Superieure de Physique et Chemie Industrialles de Paris, rue Vanquelin - 75231 Paris Cedex 05, France
(Received 9 July 1996)
The synthesis and liquid crystalline (LC) properties of side chain polyethers bearing cyanobiphenyl and other mesogenic groups are reviewed from the literature and from the author's results. The influence of different parameters, such as the length of the spacer and the sterochemistry of the main chain are discussed. The synthesis of the above LC polyethers can be realized by chemical modification reactions of already available functional polyethers or by ring-opening polymerization or copolymerization of cyclic ethers bearing a mesogenic side chain group. LC polyethers were obtained even with a very short spacer and cholesteric mesophases observed in some cases when the main chain contains chiral centers, indicating a transfer of chirality from the main chain onto the mesogen. With enough long spacers this transfer is not realized and various non-chiral smectic phases are obtained. Recently, chiral induction could be obtained in copolymerization reactions by using a chiral non mesogenic comonomer.
Key words: polyethers, liquid crystals, ring-opening polymerization, copolymerization
Synthesis of 3-cyclopropanecarbonyl-5-arylidene-2,4-dioxotetrahydro-1,3 thiazoles
KATARINA POPOV-PERGAL, MIROSLAV PERGAL and JANOS CSANADI
University of Novi
Sad, Faculty of Science, Institute of Chemistry, Trg Dositeja Obradovica 3,
YU 21 000 Novi Sad, Yugoslavia
(Received 20 June 1996)
Cyclopropanecarbonyl derivatives of ten 5-arylidence-2,4-dioxotetrahydro-1,3-thiazoles were synthesized as potential biologically active components. For the unusual derivative of 5-(3'-indolinylidene)-2,4-dioxotetrahydro-1,3-thiazole a suggestion of the synthesis mechanism is presented. For all synthesized compounds IR, 1H-NMR, 13C-NMR, M+ in MS, the bond lengths and angles of some important atoms or groups in the molecules are given.
Key words: heterocycles, synthesis, cyclopropanecarbonyl derivatives, 5-arylidene-2,4-dioxotetrahydro-1,3-thiazoles
Synthesis and biological activity of 4-phenyl-2-(L-glutamoylamino acid), 5:6-benzo-1:3-isoindolinedione derivatives
RAGABA A. EL-SAYED, N. S. KHALAF, H. A. EYADA AND M. H. EL-HAKIM
Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt
(Received 2 July 1996)
A synthesis of some 4-phenyl-2-(L-glutamoylamino acids), 5:6-benzo-1:3-isoindolinediones (II-XII) has been achieved by condensation of 4-phenyl-2-(L-glutamic anhydride), 5:6-benzo-1:3-isoindolinedione (I) with an appropriate amino acid in glacial acetic acid. Esterification of the amino acid derivatives (II-XII) in methanol-thionyl chloride gave the methyl esters (XIII-XXIII). The action of thionyl chloride on some of the amino acid derivatives afforded the acid chloride (XXIV-XXVI). The acid chloride was converted into its corresponding acid azide (XXVII-XXIX) through its reaction with sodium azide. The carbamate derivatives (XXX-XXXII) were achieved through Curtius rearrangement with methanol. Some dipeptide derivatives (XXXIII-XXXV) were synthesized via the dicyclohexylcarbodiimide method. Most of the synthesized compounds were found to be active against a number of microorganisms.
Key words: isoindelinedione derivatives synthesis, condensation with amino acids, biological activity
Transformation of the insoluble part of kraft lignin by penicillium thomii
BILJANA BUJANOVIC and TATJANA STEVANOVIC-JANEZIC
Faculty of Forestry, University of Belgrade, Kneza Viseslava 1, YU - 11000 Belgrade, Yugoslavia
(Received 8 March, revised 17 October 1996)
The degradation/transformation of the insoluble part of kraft lignin from mixed hardwoods (HKL) and from juvenile beechwood (BKL) by Penicillium thomii in liquid medium has been followed. The mold Penicillium thomii was selected in our previous research aimed at finding the most efficient microorganism in regard to the degradation/transformation of the soluble and the insoluble parts of kraft lignins in liquid media. FTIR and UV analyses of control (lignin obtained by filtration of sterilized non-inoculated substrate) and samples (lignin obtained by culture filtration after 72-hours of incubation at a temperature of 27 °C, on a rotary shaker) of kraft lignins. The methoxyl content of the described samples is determined (OCH3-groups). The results obtained by the application of the application of the described methods indicate that the enzymatic system of the mold Penicillium thomii causes the dearomatisation and demethoxylation of kraft lignins. The degradation pathway of kraft lignin by Penicillium thomii is proposed.
Key words: biodegradation of lignin, kraft lignin, penicillium thomii, aromatic content, methoxyl group content
Isolation and characterization of pathogenesis-related proteins from brewer's barley grain
ANA CVETKOVIC, STANISLAVA GORJANOVIC, JOVAN HRANISAVLJEVIC AND DUSAN VUCELIC*
General and Physical Chemistry, Studentski trg 12-16, P.O.Box 551, YU-11000
*Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, P.O.Box 137, YU-11000 Belgrade, Yugoslavia
(Received 6 May, revised 22 October 1996)
Two pathogenesis-related proteins have been isolated from brewer's barley grain. They were characterized and found to be homologous basis glycoproteins with relative molecular mass of 21 and 22 kDa and neutral sugar content of 2.8 and 5.0, respectively. The protective role of isolated proteins in barley seeds has been confirmed by their inhibitory activity on Candida albicans growth and on brewer's yeast fermenting activity.
Key words: PR-proteins, TL-proteins, Brewer's barley
Reactivity of Ti2+ and V2+ with small alkanes
YASMIN RANASINGHE, TEODOR AST AND BEN FREISER
H. C. Brown Laboratory of Chemistry, Purdue University, West Lafayette, IN 47907, USA
(Received 20 September 1996)
The reaction of Ti2+ and V2+ with small linear alkanes are reported. Bond insertion reactions are absent and only charge, hydride and methide transfer are observed. The results are found to the in qualitative agreement with a simple curve-crossing model. The reactivities of the doubly charged ions are briefly compared to their singly charged analogues. Finally, the results are also compared to those obtained for Ti2+ under the high-pressure conditions of a flowing afterglow.
Key words: Fourier transform mass spectrometer, Ti2+, V2+, curve-crossing
Relation between the number of oscillations and the activation energy of an oscillatory process
SLOBODAN R. ANIC
Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, P.O.Box 137, YU-11000 Belgrade, Yugoslavia
(Received 23 May 1996)
The number of oscillations generated during the course of an oscillatory reaction in a closed reactor in considered to be a kinetic property that is useful for determination of the activation energy of an overall process. The method applicability is illustrated on the Bray-Liebhafsky oscillatory reaction.
Key words: oscillatory reaction, Bray-Liebhafsky reaction, chemical kinetics, activation energy
Oxidation effect on galena (PbS) surface properties in the presence of lead ions
S. R. POPOV, D. R. VUCINIC and N. KARTALOVIC*
Faculty of Mining
and Geology, Department of Mineral Processing, University of Belgrade,
Djusina 7, YU-11000 Belgrade and
*Faculty of Electrical Engineering, University of Belgrade, YU-11000 Belgrade, Yugoslavia
(Received 26 March, revised 16 October 1996)
A study of the effect of lead ions on the surface phenomena of "oxidized" galena at pH 6.0-7.0 in the presence and in the absence of potassium ethylxanthate is aimed at comparing the behaviors of "oxidized" and "unoxidized" galena. The investigations were carried out using the zeta and redox potential measurements and IR data. Lead ions present in the solution affect the surface of galena that is not exposed to oxidation conditions. The redox, Ep. potential increases with the added increasing ion concentration from 5.0x10-6 mol dm-3 to 5.0x10-5 mol dm-3, indicating a reaction of anodic dissolution of the mineral coupled with a cathodic reaction of oxygen reduction. The zeta potential results show the adsorption of Pb2+ and Pb(OH)+ ions in the metal-deficient centers and in the sulphide surface centers, providing for the activation of EX anion adsorption on the galena surface. But the presence of dissolved lead ions did not significantly affect the surface properties of "oxidized" galena. The redox as well as zeta potential of "oxidized" galena remained virtually unchanged when the added lead ion concentration was varied from 5.0x10-6 mol dm-3 to 5.0x10-5 mol dm-3. The obtained results, however, suggest that the dissolved lead ion passivates the oxidation surface layer on galena. Consequently, its presence fixes the adsorbed layer composed of stoichiometric Pb(EX)2, originating from the ion exchange reaction between anion from the oxidation compounds and EX from the solution.
Key words: galena, surface, oxidation, ethylxanthate, adsorption, lead ions, flotation
A brief comparative study of the effects obtained after enzymatic and Na-dichloroisocyanurate treatment of wool
Faculty of Technology and Metallurgy, Textile Engineering Department, University of Belgrade, Yugoslavia
(Received 12 January, revised 9 September 1996)
In the present study, the efficiency of wool treatment with serine proteinase Bactosol Sl in achieving shrink-resistant properties was compared to the efficiency of the Basolan DC treated wool sample. In order to confirm the efficiency of both treatments, the area felting shrinkage, degree of whiteness, loss of weight and ball-penetration resistance loss (BPRL) were determined. The treatment of wool by Bactosol Sl has a significant positive effect in reducing wool shrinkage and at the same time significantly improved the whiteness related to the untreated sample and Basolan DC treated sample. On the other hand, the enzymatic treatment causes marked changes in the physico-mechanical characteristics of wool expressed as the loss of weigh and ball-penetration resistance loss (BPRL). The influence of enzymatic and BASOLAN DC treatment of wool on the formation of cystine derivatives on the wool surface have been studied using FTIR/A TR second order spectroscopy. The BASOLAN DC treatment of wool resulted in an increase in the cysteic acid content much greater than that in the enzymatic treated sample. Enzymatic treatment also caused an increase in Bunte salt residues. Treatment with BASOLAN DC is generally superior compared to enzymatic treatment because of the more expressed changes of weight and BPR losses after the enzymatic treatment. However, the enzymatic treatment is of interest and has several advantages from the aspect of energy saving, pollution control and safety. Further investigations, aimed at achieving better uniformity of treatment, are to be expected.
Key words: wool, enzymatic treatment, basolan dc treatment, area shrinkage, degree of whiteness, ball penetration resistance loss, comparative study