J. Serb. Chem. Soc.
62(4) 295-306 (1997)
JSCS-2384
UDK 678.5/.7
Review paper
REVIEW
Materials with new
properties - a challenge for polymer synthesis
BOGDAN
C. SIMIONESCU, VALERIA HARABAGIU*, GETA DAVID AND MARIANA PINTEALA*
"Gh.
Asachi" Technical University, Department of Macromolecules, 6600 Jassy and
*"P. Poni" Institute of Macromolecular Chemistry, 6600
Jassy, Romania
(Received 10 October 1996)
1. Introduction,
2. Free radical ring opening polymerization
3. Functional polysiloxanes and derived copolymers
3.1. Synthesis of OPSs by hydrosilation
3.2. Synthesis of OPSs by chemical transformation
3.3. Synthesis of siloxanc copolymers
4. Graft and block copolymers with poly(N-acyliminoethylene)
sequences
5. Plasma-induced polymerization
Key words: free radical ring
opening polymerization, functional polisiloxane, siloxane copolymers,
plasma-inducal polymerization
J.
Serb. Chem. Soc. 62(4) 307-317 (1997)
JSCS-2385
UDK
547.722/.728:541.251:543.424
Original scientific
paper
Stereochemistry
and 13C-NMR spectra of some phenyl selenotetrahydrofurans and
selenotetrahydropyrans obtained by phenylselenoetherification
STANIMIR
KONSTANTINOVIC* **, ZORICA BUGARCIC*, RASTKO VUKICEVIC*, WOLFGANG WISNIEWSKI**,
ZORAN RATKOVIC*, ZORAN MARKOVIC* AND MIHAILO LJ. MIHAILOVIC***
*Department
of Chemistry, Faculty of Science, University of Kragujevac, P.O.Box 60,
YU-34000 Kragujevac, Yugoslavia
**Max-Plank Institut fur Kohlenforschung, P.O.Box 101353,
D-45466 Mulheim - Ruhr, Germany, and
***Faculty of Chemistry, University of Belgrade, P.O.Box 158,
YU-11000 Belgrade, and Institute of Chemistry Technology and Metallurgy,
Belgrade, Yugoslavia
(Received 10 October 1996)
The 13C-NMR spectra of some phenyl
selenotetrahydrofurans and selenotetrahydropyrans, obtained by phenylselenoetherification
of the corresponding unsaturated alcohols, have been recorded and studied as a
function of their stereochemistry. By using the MMX (PC MODEL) force field
(extended with some new parameters), the prepared phenyl selenotetrahydropyrans
have also been theoretically studied.
Key words: phenyl
selenotetrahydrofurans, selenotetrahydropyrans, stereochemistry, 13C-NMR
spectra
J. Serb. Chem. Soc. 62(4) 319-325 (1997)
JSCS-2386
UDK
541.61:547.53.513.3
Original scientific
paper
On the
calculation of the algebraic structure count of polycyclic conjugated hydrocarbons
by means of cell polynomial
PETER
JOHN and IVAN E. GUTMAN*
Institute
of Mathematics, Technical University of Ilmenau, P.O.Box 565, D-98693 Ilmenau,
Germany, and
*Faculty of Science, University of Kragujevac, P.O.Box 60,
YU-34000 Kragujevac, Yugoslavia
(Received 11 November 1996)
The cell polynomial (also known under the name "resonant
ring polynomial" or "R-polynomial") is a proper extension
of the Hosoya-Yamaguchi's sextet-polynomial-concept from benzenoid molecules to
arbitrary polycyclic alternant connjugated p-electron systems. In the ease
of catacondensed molecules the cell polynomial enables a straightforward
evaluation of the Kekule structure count. We now show that the calculation of
the algebraic structure count is a task more difficult than initially
anticipated, and that it cannot be accomplished using solely the cell
polynomial.
Key Words: Clar theory,
Kekule structures, algebraic structure count, cell polynomial
J. Serb. Chem. Soc. 62(4) 327-333 (1997)
JSCS-2387
UDK
543.78/.888:541.121/.123
Original scientific
paper
Reaction
extents in systems with multiple chemical equilibria
IVAN
GUTMAN, ISTVAN NAGYPAL* and ILIE FISHTIK**
Faculty
of Science, University of Kragujevac, P.O.Box 60, YU-34000 Kragujevac,
Yugoslavia
*Institute of Physical Chemistry, Attila Josef University,
P.O.Box 105, H-6701 Szeged, Hungary and
**Institute of chemistry, Academy of Science of Moldova, 277028
Kishinev, str. Academiei 3, Republica Moldova
(Received 10 October 1996)
It is shown that in multiple-equilibrium systems the reaction
extents are uniquely determined only if all the equilibria considered are
stoichiometrically independent. Otherwise numerical values for reaction
extents, satisfying the mass-balance conditions, can be chosen in infinitely
many ways. Irrespective of this, every reaction affinity (the derivative of the
Gibbs energy with respect to the reaction extent. These results corroborate the
validity of the recently elaborated response-reaction-approach to chemical
thermodynamics.
Key words: reaction extent,
extent of chemical reaction, multiple-equilibrium systems, chemical
thermodynamics
J. Serb. Chem. Soc. 62(4) 335-341 (1997)
JSCS-2388
UDK
547.587.11:546.562:541.42849
Original scientific
paper
Spectrophotometric
study of the complex-formation equilibria between some salicylic acid
derivatives and copper(II) ions
GYONGYI
GY. VASTAG, TEREZIA M. SURANYI and EVGENIJA DJURENDIC
Institute
of Chemistry, Faculty of Science, Novi Sad, Trg D. Obradovica 3, YU-21000 Novi
Sad, Yugoslavia
(Received 7 August, revised 24
December 1996)
The equilibria occurring in solution of 1,n-di-O-salicyloyl-alkane-1,n-diols
(n=2-8) and N,N-disalicyloyl-1,n-alkanediamines (n=2-4)
with copper(II) ions have been studied by a spectrophotometric method. The
complex-formation constants have been determined in 61.10% aqueous ethanol at
298 K and l = 0.5 mol dm-3 ((Li)Cl). As the determinations
were performed in a glycinate buffer, these constants were corrected for the
side reaction of copper(II) with glycine.
Key words: copper(II)
complexes, salicylic acid derivatives, complex equilibria
J. Serb. Chem. Soc. 62(4) 343-348 (1997)
JSCS-2389
UDK
622.337:628.35:549.324.31
Original scientific
paper
Bacterial
depyritization of oil shale by thiobacillus ferrooxidans. The effect of initial
pH value
VESNA
DRAGUTINOVIC, MIROSLAV VRVIC*, OLGA CVETKOVIC, JOVAN VUCETIC* and DRAGOMIR
VITOROVIC*
Center
of Chemistry, Institute of Chemistry Technology and Metallurgy, Njegoseva 12,
P.O.Box 815, YU-11001 Belgrade, and
*Faculty of Chemistry, University of Belgrade, Akademski trg,
P.O.Box 158, YU-11001 Belgrade, Yugoslavia
(Received 13 December 1996)
The efficiencies of depyritization of Aleksinac (Yugoslavia) oil
shale concentrates with Thiobacillus ferrooxidans (Th.f.) strain A5
were studied at initial pH values of 2.5 (favorable for Th.f. strain in
a medium containing Fe(II)-ions), 2 and 1.5 (preventing the precipitation of
Fe(III)-ion hydrolysis products). The investigated samples (HCl-and HCl-kerogen
concentrates) were suitable as substrates for bacterial depyritization since
they both originated from oil shale with less than 1 bitumen. The bioleaching
efficiency was found to decrease with decreasing initial pH, which is probably
due to the difference in pHs within the cell and the environment, i.e.,
the medium. Nevertheless, based on the ratio of the efficiency of bacterial
depyritization vs. the number of microorganisms, an initial pH of 2 might be
considered optimal, presumably because the precipitation of Fe(III)-ion
hydrolysis products has at least been partially prevented.
Key words: oil shale, thiobacillus ferrooxidans,
depyritization
J.
Serb. Chem. Soc. 62(4) 349-351 (1997)
JSCS-2390
UDK
535.343.546.11:546.659'732''
Original scientific
paper
Kinetics
of hydrogen absorption in a powdered SmCo5 alloy
MILENKO
SUSIC
Serbian
Academy of Science and Arts, Belgrade, and Faculty of Physical Chemistry,
University of Belgrade, P.O.Box 137, YU-11001 Belgrade,
Yugoslavia
(Received 15 November 1996)
It is known that the polycrystalline powdered intermetallic
lanthanide SmCo5 may be brought to an active hydrogen absorber in
the temperature range of 80 to 500°C, with an enthalpy of 100 J/g or more. The
most important kinetic and thermodynamic parameters of the process are
determined, such as rate constants, enthalpies and energies of activation.
Key words: hydrogen
absorption, kinetics of, SmCo5, intermetallic lanthanide
J. Serb. Chem. Soc. 62(4) 353-359 (1997)
JSCS-2391
UDK 547.262:541.18.045.5:549.67
Original scientific
paper
Laboratory
process for ethanol drying in a fixed bed of the zeolite 3A
SVETOMIR
MIJOVIC, MILAN MITROVIC and DUSAN VUCELIC*
Institute
of General and Physical Chemistry, Studentski trg 12-16, P.O.Box 551, YU-11000
Belgrade and
*Faculty of Physical Chemistry, University of Belgrade,
Studentski trg 12-16, P.O.Box 137, YU-11001 Belgrade, Yugoslavia
(Received 7 June 1996, revised
17 Januaty 1997)
The conditions for the process of a liquid phase dehydration of
ethanol were investigated. The dehydration was performed in a fixed bed
adsorption column of granular molecular sieve 3A, which was confirmed, as it is
already known, to be the most efficient desiccant for organic solvents. The
dynamic capacity of the adsorbent, as well as the cross-over ratio between the
mass transfer zone (MTZ) and the heat wave developed during the adsorption
step, were determined. The results of the experiments form the basis for the
design of an industrial process to produce absolute ethanol, using a
temperature swing adsorption (TSA) cycle.
Key words: adsorption
drying, ethanol drying, zeolite 3A, cross-over ratio
J. Serb. Chem. Soc. 62(4) 361-365 (1997)
JSCS-2392
UDK
666.94.053:622.785:666.942.3
Original scientific
paper
Sintering
of mechanically activated raw material mixtures used for obtaining
portland-cement clinker
ZIVKO
SEKULIC, SINISA MILOSEVIC, DEANA ZIVANOVIC, ALEKSANDRA ROSIC* and MIODRAG
STEFANOVIC**
Institute
for Technology of Nuclear and Other Mineral Raw materials, Franse d`Eperea86,
YU-11000 Belgrade,
*Faculty of Mining and Geology, Laboratory for Crystallography,
Djusina 7, YU-11000 Belgrade, and
** Cement Factory "Novi Popovac", Popovac, Yugoslavia
(Received 21 November 1996)
In this study the sintering of unactivated and mechanically
activated raw material mixtures used for obtaining portland cement clinker was
investigated. The optimal times for mechanical activation of the individual
components and raw material mixtures were previously determined. The mechanical
activation experiments were performed in a vibro mill with rings. It was found
that mechanical activation of the raw material mixture caused not only an
increase of the specific surface energy, but also structural changes in certain
mineral components of the starting mixture, causing an increase of their
reactivity, followed by intensified mass transfer during sintering. In this
way, the sintering process was made more efficient, and the degree of the
reactions occurring in the solid phase during the formation of the clinker
mineral was higher. The effects of the mechanical activation method were also
evident in the results of diffractometric analyses of the main clinker
minerals. An increase of the tricalciumsilicate content from 51%, in the
clinker produced from the inactivated raw material mixtures, to 62%, in the
clinker produced from the activated mixture, at the sintering temperature of
1350°C, (about 100°C lower than the temperature which is standard for cement
clinker production), was registered.
Key words: mechanical
activation, vibro mill, portland cement clinker, sintering
J. Serb. Chem. Soc. 62(4) 367-369 (1997)
JSCS-2393
UDK
546.15:543.242:546.215
Note
NOTE
Simulation of iodine oxidation by hydrogen peroxide in acid
media, on the basis of the model of Bray-Liebhafsky reaction
MIRJANA
RADENKOVIC, GUY SCHMIT* and LJILJANA KOLAR-ANIC**
Vinca
Institute of Nuclear Science, P.O.Box 522, YU-11001, Belgrade,
*Faculty of Applied sciences, U. L. B. CP-165, B-1050 Bruxelles,
Belgium and
**Faculty of Science, University of Belgrade, P.O.Box 137,
YU-11001 Belgrade, Yugoslavia
(Received 15 November 1996)
The kinetics of iodine oxidation by hydrogen peroxide in acid
media has been investigated. The Bray-Liebhafsky oscillatory reaction takes
place in the same reaction system and the process of iodine oxidation by
hydrogen peroxide presents an important part of its mechanism. The dependence
of the rate of iodine oxidation by hydrogen peroxide presents an important part
of its mechanism. the dependence of the rate of iodine oxidation on the initial
value of the hydrogen peroxide concentration, [H2O2]0,
and the existence of an unusual phenomenon, the maximum value of the
experimentally found reaction rate constant, in respect to [H2O2]0
have been successfully simulated on the basis of a kinetic model of the
Bray-Liebhafsky reaction.
Key words: Bray-Liebhafsky
reaction, iodine oxidation, kinetic models
J. Serb. Chem. Soc. 62(4) 371-374 (1997)
JSCS-2394
UDK
546.623:541.5:541.127.1
Original scientific
paper
Kinetic
determination of Al(III) in solution
RANGEL
P. IGOV, VIOLETA D. MITIC and TODOR G. PECEV
Department
of Chemistry, Faculty of Philosophy, University of Nis, Cirila i Metodija 2,
YU-18000 Nis, Yugoslavia
(Received 9 July, revised 6
December 1996)
A new kinetic method is elaborated for the determination of
Al(III) traces in solution, on the basis of their inhibiting effect on purpurin
oxidation by H2O2 in boric buffer catalyzed by Co(II) ions. Using a
spectrophotometric technique, a sensitivity of 6.0×10-8 to 10×10-8
g cm-3 Al(III) was achived. The relative error was 1.8 % to 5.7% for
Al(III) in the concentration intervals of 5.0×10-8 to 10×10-8
g cm-3. The kinetic equations for this process are given. The method
has relatively good selectivity.
Key words: aluminum, kinetic
determination, purpurin
J. Serb. Chem. Soc. 62(4) 375-380 (1997)
JSCS-2395
UDK 546.492:543.06:541.127.1
Original scientific
paper
A new
kinetic method for the determination of Hg(II)
R. P.
IGOV, G. MITIC, S. MILETIC and S. MITIC
Department
of Chemistry, Faculty of Philosophy, University of Nis, Cirila i Metodija 2,
YU-18000 Nis, Yugoslavia
(Received 20 September 1996,
revised 6 January 1997)
A kinetic method is described for the determination of Hg(II)
based on its inhibiting effect on the oxidation of sodium
2-thiosemicarbazone-1,2-naphthoquinone-4-sulphonate by hydrogen peroxide. The
sensitivity of the method is 0.1 µg cm-3. The relative error ranges
between 2.4 and 13.5% for the concentration interval 1.0 to 0.2 µg cm-3.
The effect of certain foreign ions upon the reaction rate were determined for
the assessment of the selectivity of the method. Kinetic equations were
proposed for the investigated process.
Key words: kinetic method,
mercury determination, sodium
2-thio-semicarbazone-1,2-naphthoquinone-4-sulphonate
J. Serb. Chem. Soc. 62(4) 381-386 (1997)
JSCS-2396
UDK
546.26:541.18.08:543.545
Original scientific
paper
Separation
of C60 and its radical adducts by high performance liquid
chromatography (HPLC)
ZORAN
SAPONJIC and NADA DIMITRIJEVIC
Laboratory
for Radiation Chemistry and Physics, Vinca Institute of Nuclear Science,
P.O.Box 522, YU-11001, Belgrade, Yugoslavia
(Received 20 September, revised
19 November 1996)
The possibility of separating a mixture of radical adducts of
fullerene was investigated using non-aqueous reversed-phase HPLC on C18
silica. Mobile phases of different compositions, all containing benzene as a
main solvent, were used. Results have shown that the separation factors
increase with increased concentration of polar solvent in the mobile phase.
Also, a better separation was obtained with polar solvents of higher dielectric
constants, the order of separation was as follows: acetonitrile > methanol
> propanol-2 > i-butanol.
Key words: fullerene, HPLC,
radical adducts
J. Serb. Chem. Soc. 62(4) 387
(1997)
Errata