JSCS Vol 69, No. 10
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Impresum |
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J. Serb. Chem.
Soc. 69 (10) 711–736 (2004) |
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R E V I E W
Alkylation of
N-substituted 2-phenylacetAMides
DUSAN Z. MIJIN*, MILICA M. MISIC-VUKOVIC* and
SLOBODAN D. PETROVIC*,**
*Department of Organic Chemistry, Faculty of Technology and
Metallurgy, Universitiy of Belgrade, P. O. Box 3503, 11120 Belgrade and
**Hemofarm group, Beogradski put bb, Vrsac, Serbia and Montenegro
(Received 24 February
2004)
Various N-substituted phenylacetAMides were
alkylated using different alkylating agents under neutral and basic conditions.
Reactions were performed at different reaction temperatures and in various
solvents. Also, a number of various catalysts were used including
phase-transfer catalysts. Reactions were followed using GC or GC-MS technique
and the presence as well as the yields of the alkylation products were
established. Generally, the best yield and high selectivity in the studied
reactions were achieved under basic conditions where in the certain cases some
products, mostly N-product, were obtained solely in quantitative yields.
Keywords: alkylation, AMides, phenylacetAMides, alkylation under neutral
conditions, alkylation under basic conditions, phase-transfer conditions.
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J. Serb. Chem.
Soc. 69 (10) 737–747 (2004) |
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Stereoselective free radical phenylsulfenylation of a nonactivated d-carbon
atom
GORAN PETROVIC*, RADOMIR N. SAICIC*,**,
LJILJANA DOSEN-MICOVIC* and ZIVORAD CEKOVIC*,**
*Faculty of Chemistry,
University of Belgrade, Studenski trg 16, P.O. Box 158, 11000 Belgrade and
**Centar for Chemistry, Institute of Chemistry, Technology and Metallurgy,
Njegoseva 12, 11001 Belgrade, Serbia and Montenegro
(Received 15 March 2004)
A stereoselective free radical introduction of a
phenylthio group onto a nonactivated methyl group in the d-position, adjacent to a prochiral carbon atom, was achieved by
photolysis of (-)-menthyl benzenesulfenate in the presence of hexabutylditin
and (1R, 3R, 4S, 8S)-9-phenylthiomenthol (4)
was obtained with 91 % optical purity. High stereoselectivity of the reaction
was calculated (ab initio MP2/6-31G**) to be the consequence of the
difference in the transition state eneregies (DDG# = 5.08
kJ/mol) favouring 4 relative to (1R,3R,4S,8R)-9-phenylthiomenthol
(5). The absolute configuration of a the new chiral carbon atom was
confirmed by its correlation with the corresponding menthane-3,9-diol of known
stereochemistry.
Keywords: radical reactions, stereoselective reactions, C-H activation, absolute
configurations, ab initio calculations, menthyl benzenesulfenate,
9-phenylthiomenthol.
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J. Serb. Chem.
Soc. 69 (10) 749–757 (2004) |
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MS analysis of biindenylidenes
SNEZANA SINADINOVIC-FISER and JOVAN JOVANOVIC*
Faculty of Technology,
University of Novi Sad, Bul. Cara Lazara 1, 21000 Novi Sad and
*Faculty of Technology and Metallurgy, University of Belgrade, P. O. Box 3503,
11120 Belgrade, Serbia and Montenegro
(Received 17 February
2004)
Biindenylidene isomers
are components of pyrolysis oils. The mass spectra were recorded and the fragmentation
of the following biindenylidene isomers: (E)-2,3,2’,3’-tetrahydro-[1,1’]biindenylidene,
(Z)-2,3,2’,3’-tetrahydro-[1,1’]biindenylidene,
1,3,1’,3’-tetrahydro-[2,2’]biindenylidene and
2,3,1’,3’-tetrahydro-[1,2’]biindenylidene, as well as of spiro[1,1a,6,6a-tetrahydrocyclopropa[a]indene-1,1’-2’,3’-dihydro-1’H-indene]
is discussed.
Keywords: mass spectrometry, fragmentation, biindenylidenes.
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J. Serb. Chem.
Soc. 69 (10) 759–767 (2004) |
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Temperature dependence of the Kovats retention
indices for alkyl 1,3-diketones on a DB-5 capillary column
DUSAN Z. MIJIN and DUSAN G. ANTONOVIC
Department of Organic
Chemistry, Faculty of Technology and Metallurgy, University of Belgrade, P. O.
Box 3503, 11120 Belgrade, Serbia and Montenegro
(Received 20 January,
revised 19 April 2004)
A series of alkyl 1,3-diketones were used to
study the temperature dependence of the Kovats retention indices in the
temperature range 130–190 ºC (403–463 K). The temperature dependence is
described by the empirical equation I = B + B/T + ClnT.
On the basis of this equation, the activation enthalpy, DH#, and the chemical potential of the partitioning
of one methylene group between the two phases of the chromatographic system, Dmp(CH2), were calculated. Also,
the Kovats retention indices – boiling point correlations (linear and
reciprocal) for alkyl 1,3-diketones were studied and Dmp(CH2) was calculated.
Keywords: retention indices, alkyl 1,3-diketones, temperature dependence.
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J. Serb. Chem.
Soc. 69 (10) 769–775 (2004) |
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PRELIMINARY COMMUNICATION
Synthesis of a steroidal dendrimer core
TATJANA KOP, GABRIELLA POCSFALVI** and BOGDAN A.
SOLAJA
Faculty of Chemistry,
University of Belgrade, P. O. Box 158, 11001 Belgrade, Serbia and Montenegro
and
*Istituto di Scienze dell’Alimentazione, Consiglio Nazionale delle Ricerche,
Avellino, Italy
(Received 26 February
2004)
Synthesis of a steroidal dendrimer core
possessing various functional termini, such as ester, carboxy and hydroxy, is
presented. The approach described enables further simple manipulations for the
introduction of more complex functionalities.
Keywords: deoxycholic acid, trimesoyl trichloride, core, dendrimer.
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J. Serb. Chem.
Soc. 69 (10) 777–782 (2004) |
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Dependence of the total p-electron energy on a large number of non-bonding molecular
orbitals
IVAN GUTMAN, DRAGAN STEVANOVIC*, SLAVKO
RADENKOVIC, SVETLANA MILOSAVLJEVIC and NATASA CMILJANOVIC
Faculty of Science,
University of Kragujevac, P. O. Box 60, 34000 Kragujevac and
*Department of Mathematics, Faculty of Science, University of Nis, Visegradska
33, 18000 Nis, Serbia and Montenegro
(Received 8 March 2004)
Using a recently developed method for computing
the effect of non-bonding molecular orbitals (NBMOs) on the total p-electron energy (E), it was found that the dependence of E
on the number n0 of NBMOs is almost perfectly linear. We
now show that this regularity remains valid for very large values of n0,
in particular, to hold up to n0 = 20.
Keywords: total p-electron energy,
non-bonding molecular orbitals, chemical graph theory.
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J. Serb. Chem.
Soc. 69 (10) 783–790 (2004) |
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Oxidative performance and surface properties of Co-containing mixed oxides
having the K2NiF4 structure
LAITAO LUO, HUA ZHONG and XIAOMAO YANG
Institute of Applied
Chemistry, Nanchang University, Nanchang, Jiangxi, 330047, P. R. China
(Received 9 December
2003, revised 2 April 2004)
The complexed oxides Nd2–xSrxCoO4
(0.4 < x < 1.2) and LnSrCoO4 (Ln = Pr, Nd, Eu)
having the K2NiF4 structure were synthesized by the
citric-acid-complexion method. The results of XRD confirmed that the complexed
oxides have the K2NiF4 structure. Other phases were found
when x = 0.4 and x = 1.2. The influences of Nd, Pr, Eu on the
activities of LnSrCoO4 for CO oxidation and C3H8
oxidation were different. The oxidative activities, average crystalline size
and lattice distortion of Nd2–xSrxCoO4
increased with increasing x value in the oxides. When x > 0.8, the
lattice distortion decreased with increasing x. The results of O2–TPD
showed that AMount of desorption of lattice oxygen over Nd2–xSrxCoO4
increased with x, however, the AMount of chemidesorption of oxygen decreased.
With increasing x, the high-temperature reduction peak in H2–TPR of
Nd2–xSrxCoO4 shifted to higher temperatures,
however, the low-temperature reduction peak shifted to lower temperatures,
which showed that the activity of the lattice oxygen and the thermal stability
of Nd2–xSrxCoO4 increased with increasing x.
Keywords: rare earths, Co-based mixed oxides, perovskite-like, oxidation.
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J. Serb. Chem.
Soc. 69 (10) 791–805 (2004) |
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An impedance investigation of corrosion protection of copper by self-assembled
monolayers of alkanethiols in aqueous
solution
GUIYAN LI*, HOUYI MA*, YONGLI JIAO* and SHENHAO
CHEN*,**
*Department of
Chemistry, Shandong University, Jinan, 250100, P. R. China and
**State Key Laboratory for Corrosion and Protection of Metals, Shenyang,
110015, P. R. China
(Received 18 August
2003, revised 1 March 2004)
Self-assembled monolayers (SAMs) of three n-alkanethiols,
1-octadecanethiol (C18SH), 1-dodecanethiol (C12SH), and 1-hexanethiol (C6SH),
were formed on fresh, oxide-free copper surfaces obtained by HNO3 etching.
The corrosion protection abilities of the three alkanethiol SAMs were evaluated
in 0.2 mol cm-3 NaCl, 0.2 mol cm-3 HCl and 0.2 mol dm-3
H2SO4 solutions using the electrochemical impedance
spectroscopy (EIS) method. The SAMs act as a hydrophobic barrier layer, which
effectively prevents the copper substrate from contacting corrosive ions,
thereby inhibiting corrosion of the copper to a considerable degree. A general
equivalent circuit for the SAM-covered electrodes was proposed, by means of
which the impedance behavior of the electrodes was interpreted and the
corresponding electrochemical parAMeters were acquired. In addition, the
quality of the SAMs and development of defects in the SAMs were also been
evaluated based on the equivalent circuit. The dependence of the capacitance of
the SAMs on the applied potentials was used to determine the stability of the
SAMs at the applied potentials.
Keywords: electrochemical impedance spectroscopy (EIS), self-assembled
monolayers (SAMs), alkanethiol, corrosion protection, equivalent circuit.
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J. Serb. Chem.
Soc. 69 (10) 807–815 (2004) |
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Electrochemical deposition and characterization of Zn–Fe alloys
JELENA B. BAJAT, VESNA B. MISKOVIC-STANKOVIC,
MIODRAG D. MAKSIMOVIC, DAGUTIN M. DRAZIC* and SLAVICA ZEC**
Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4,
P.O. Box 3503, 11120 Belgrade,
*ICTM – IEC, P.O.Box 815, 11001 Belgrade and
3Vinca Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade, Serbia and
Montenegro
(Received 7 May 2004)
Zn–Fe alloy electrochemically deposited on steel
under various deposition conditions were investigated using anodic linear sweep
voltAMmetry (ALSV) and X-ray diffraction (XRD) analysis for phase structure
determination, energy dispersive X-ray (EDX) analysis for determination of
chemical composition, and polarization measurements and open circuit potential
measurements for determination of corrosion properties. The influence of
deposition current density on the chemical composition, phase structure and
corrosion stability of Zn–Fe alloys was studied. It was shown that deposition
current density strongly affects the corrosion stability of Zn–Fe alloys, while
Zn–Fe alloy electrodeposited at 4 A dm-2 exhibited the lowest
corrosion rate.
Keywords: electrodeposition, Zn–Fe alloy, corrosion, surface modification.
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J. Serb. Chem.
Soc. 69 (10) 817–825 (2004) |
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The effect of the particle shape and structure on the flowability of
electrolytic copper powder.
IV. The internal structure of the powder particles
KONSTANTIN I. POPOV, SNEZANA B. KRSTIC, MIOMIR
G. PAVLOVIC*, LJUBICA J. PAVLOVIC* and VESNA M. MAKSIMOVIC**
Faculty of Technology
and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade,
*ICTM – Department of Electrochemistry, Njegoseva 12, 11000 Belgrade and
**Vinca Institute of Nuclear Sciences, P. O. Box 522, 11000 Belgrade, Serbia
and Montenegro
(Received 26 January
2004)
The structure of powder
particles was analysed by considering their cross sections. It was shown that
the structure of powder particles of nonsieved flowing powders is sufficiently
dense to produce a continuous surface, which does not allow the particles to
jAM and hence permits the free flow of nonsieved powder. It was also shown that
the representative powder particle, the elementary cell of which can be
presented by a 3D-cross, describes the properties of the powder relative to its
flowability well.
Keywords: copper powder
flowability, nonsieved flowing powder, cross section of powder particles.
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J. Serb. Chem.
Soc. 69 (10) 827–837 (2004) |
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Energy and economy
savings in the process of methanol synthesis using Pinch technology
MIRJANA KIJEVCANIN, BOJAN DJORDJEVIC, OZREN OCIC*,
MLADEN CRNOMARKOVIC, MAJA MARIC and SLOBODAN SERBANOVIC
Faculty of Technology
and Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 35-03, 11000
Belgrade and
*Pancevo Petroleum Refinery, Spoljnostarcevacka b.b., 26000 Pancevo, Serbia and
Montenegro
(Received 21 October
2003, revised 6 April 2004)
A heat exchanger network
(HEN) for the process of methanol synthesis has been studied by pinch design
analysis. Great economic and energy savings were realized by the pinch analysis
in comparison to the existing plant. Also, it was found that it is possible to
reduce the requirements for the consumption of utilities. The HEN was
reconstruded by adding new heat exchangers. In order to produce new HEN, the
capital costs had to be increased, but the total cost trade-off between the
capital and energy costs will be decrease by 30 %.
Keywords: energy
recovery, pinch technology, HEN design, plant for methanol synthesis.
Copyright &AMp; copy; SHD 2004.
November 23, 2004.
For
more information contact: JSCS@tmf.bg.ac.yu