JSCS Vol 72, No. 2
Whole issue - PDF 
(1.238
KB WinZip file)
UDC
551.583:531.3+536.7:546.33'135+547.292–38, JSCS–3538, doi:
10.2298/JSC0702089M; Original scientific paper
Kinetic
study of the reaction between sodium chloroacetate and potassium
ethylxanthogenate
MILUTIN MILOSAVLJEVIC, ALEKSANDAR
MARINKOVIC, BOBAN CEKOVIC* and SLAVICA RAZIC**
Faculty of Technology and Metallurgy,
*Military Technical Institute,
**Faculty of Pharmacy,
(Received 1 August, revised
The reaction kinetics of the synthesis
of sodium ethyl xanthogeneacetate from potassium ethylxanthogenate and sodium
chloroacetate in distilled water as the reaction medium at 25, 30, 35 and 40
°C, were investigated. The obtained reaction mixture was a complex system which
demanded the use of two methods for the kinetic measurements. The reaction was
followed using the conductrometric and UV/Vis spectrophotometric method with
equimolar initial concentrations of the reactants and under pseudo-first order
conditions with respect to one of the reactants. The rate constants of the
pseudo-first order and second order reactions were calculated from the data. On
the basis of the reaction constants, the activation parAMeters were calculated
and are discussed.
Keywords:
kinetic rate, rate constant, sodium ethyl xanthogeneacetate, thermodynAMic
parAMeters.
Full Article - PDF 127 KB
J.
Serb.Chem. Soc. 72 (2) 101–107 (2007)
UDC
547.216'466.1+547.466.23'466.1:615.281, JSCS–3539, doi: 10.2298/JSC0702101D; Original scientific paper
First
total synthesis and biological evaluation of halolitoralin A
RAJIV DAHIYA and DEVENDER PATHAK
(Received
A new potent bioactive alanine-rich
cyclic hexapeptide halolitoralin A(8), which was previously isolated from the
marine sediment-derived bacterial strain Halobacillus
litoralis YS3016, has been synthesized by the solution phase technique. All
the coupling reactions were performed at room temperature utilizing
dicyclohexylcarbodiimide (DCC) as the coupling reagent and N-methylmorpholine
(NMM) as the base. The structure of the peptide was characterized by IR, 1H-NMR,
13C-NMR, FAB MS spectral data, as well as elemental analysis and
DSC. The synthesized cyclopeptide was also screened for its antimicrobial and
anthelmintic activities and found to exhibit potent antifungal activity against
the pathogenic fungi Candida albicans
and Trichophyton mentagrophytes along
with potent antibacterial activity against the grAM negative bacteria Pseudomonas aeruginosa and Escherichia coli. GrAM negative bacteria
were found to be more sensitive than grAM positive bacteria towards the newly
synthesized peptide. In addition, the peptide was also found to exhibit
moderate anthelmintic activity against the earthworms Megascoplex konkanensis
and Eudrilus sp.
Keywords:
halolitoralin A, cyclic hexapeptide, alanine-rich peptide, antimicrobial
activity, anthelmintic activity.
Full Article - PDF 107 KB
J. Serb.
Chem. Soc. 72 (2) 109–117 (2007)
UDC 542.913+547.853/.854:615.281,
JSCS–3540, 10.2298/JSC0702109V;
Original scientific paper
Microwave
assisted synthesis and antimicrobial activity of some novel pyrimidine
derivatives
S. J. VAGHASIA and V. H. SHAH
Department of Chemistry,
(Received
The synthesis of thiazolo [5,4-d]pyrimidines can be achieved from
different 5-thiazolidinones, 2-butyl-1H-imidazole-5-carbaldehyde
and thiourea using microwave irradiation within 5 min. The structures of the
products were supported by FTIR, PMR and mass spectral data. The in vitro antimicrobial activity of the
synthesized thiazolo [5,4-d]pyrimidines 1a-j,
having substituents at the 1- and 3-positions, were determined by the cup-plate
method against several standard strains chosen to define the spectrum and
potency of the new compounds. The antimicrobial activities of the thiazolo
[5,4-d]pyrimidines 1a-j are compared
with those of known chosen standard drugs, viz.
AMpicillin, chlorAMphenicol, ciprofloxacin, norfloxacin and griseofulvin.
Keywords: microwave irradiation, thiazolo
[5,4-d]pyrimidines, antimicrobial activity.
Full Article -
PDF 99 KB
J. Serb. Chem. Soc. 72 (2) 119–127
(2007)
UDC 542.913+667.281.2:677.042.4:579–188,
JSCS–3541, 10.2298/JSC0702119D;
Original scientific paper
Synthesis and application of new mordent and disperse
azo dyes based on 2,4-dihydroxybenzophenone
BHARAT C. DIXIT, HITENDRAM. PATEL and
DHIRUBHAI J. DESAI
Department of Chemistry, V.
(Received
Novel mordent and disperse azo dyes were prepared by
the coupling of various diazo solutions of aromatic AMines with
2,4-ihydroxybenzophenone. The resultant dyes were characterized by elemental
analyses as well as IR and NMR spectral studies. The UV-visible spectral data
have also been iscussed in terms of
structural property relationship. The dyeing assessment of all the dyeswas
evaluated on wool and polyester textile fibers. The dyeing of chrome treated (i.e., chrome mordented) wool and
polyesters was also monitored. The results show that a better hue was obtained
on mordented fibers. The results of the anti-bacterial properties of the chrome
dyes revealed that the toxicity of these dyes against bacteria is fairly good.
Keywords: disperse dye,mordent dye, UVabsorber, dyeing,
antimicrobial activity.
Full Article -
PDF 98 KB
J. Serb. Chem. Soc. 72 (2)
129–132 (2007)
UDC 547.82.004.14+66.094.3:661.183.7,
JSCS–3542, doi: 10.2298/JSC0702129A; Short communication
SHORT
COMMUNICATION
The use of pyridinium fluorochromate (PFC)
supported on TriSyl silica gel for oxidation reactions
FATMA AYDIN and
ERSAN TURUNC*
*
(Received 23
March, revised
Pyridinium
fluorochromate supported on TriSyl silicas was prepared by co-adsorption. The
supported reagent was used in equimolar quantity to oxidise some organic
compounds with good yields and complete selectivity. These procedures are mild,
efficient, safe and the work-ups are very convenient.
Keywords: oxidation, pyridinium
fluorochromate (PFC), TriSyl silicas.
Full Article -
PDF 69 KB
J. Serb. Chem.
Soc. 72 (2) 133–138 (2007)
UDC
582.936:549.25+549.328.1, JSCS–3543, doi: 10.2298/JSC0702133R; Original
scientific paper
Content of heavymetals in
Gentiana lutea L. roots and galenic forms
DRAGOJA RADANOVIC, SVETLANA
ANTIC-MLADENOVIC*, MIODRAG JAKOVLJEVIC* and MIRJANA KRESOVIC*
Institute for Medicinal Plants Research
"Dr Josif Pancic", Tadeusa Koscuska 1, 11000
*Faculty of Agriculture, Nemanjina 6, 11080
(Received 24 March, revised
An experimental field for the cultivated
production of Gentiana lutea L. was established five years ago at the
Suvobor Mountain, Serbia. Soil analysis of this area revealed the occurrence of
high pseudo-total (Ni – 1270 mg/kg, Cr – 423 mg/kg, Co – 385 mg/kg) and
available (especially Ni – 133 mg/kg) heavy metals contents in the soil. Hence,
the aim of this research was to evaluate the quality of Gentiana lutea
L. – roots and galenic forms (liquid extract in 70 % ethanol, spissum and
siccum) produced from the roots, because, for most plants, heavy metals
accumulate in the root tissue. The AMounts of Ni and Cr found in the analyzed
roots were very high (54 mg/kg and 14 mg/kg, respectively). The efficiency of
ethanol in extracting heavy metals from the roots varied depending on the
particular element. The highest efficiency was obtained for Ni (41.3 %), then
for Cd (39.5 %), Pb (37.0%) and Co (30.4 %). According to this, a potential
hazard exists for humans, if gentian's galenic forms are produced from the raw
material with high heavy metals contents. It is concluded that quality control
of the raw material must be carried out before further utilization of gentian.
Keywords:
gentian, root, ethanol extract, nickel, chromium.
Full Article -
PDF 93 KB
J. Serb. Chem. Soc. 72 (2) 139–150(2007)
UDC
678.84.004.14+542.913+678.073/.074, JSCS–3544, doi: 10.2298/JSC0702139A; Original
scientific paper
Application of
reactive siloxane prepolymers for the synthesis of thermoplastic
poly(ester–siloxane)s and poly(ester–ether–siloxane)s
VESNA V. ANTIC, MARIJA V.
VUCKOVIC and JASNA DJONLAGIC*
*Faculty of Technology of
Metallurgy, Karnegijeva 4, 11000
Thermoplastic
poly(ester–siloxane)s (TPES) and poly(ester–ether–siloxane) s, (TPEES), based
on poly(butylene terephthalate) (PBT) as the hard segment and different
siloxane-prepolymers as the soft segments, were prepared. The TPES and TPEES
were synthesized by catalyzed two-step transesterification from dimethyl
terephthalate, (DMT), 1,4-butanediol, (BD) and a siloxane-prepolymer.
Incorporation of dicarboxypropyl- or disilanol-terminated
poly(dimethylsiloxane)s (PDMS) into the polar poly(butylene terephthalate)
chains resulted in rather inhomogeneous TPES copolymers, which was a
consequence of a prononuced phase separation of the polar and non-polar
reactants during synthesis. Two concepts were employed to avoid or reduce phase
separation: 1) the use of siloxane-containing triblock prepolymers with
hydrophilic terminal blocks, such as ethylene oxide (EO), poly(propylene oxide)
(PPO) or poly(caprolactone) (PLC) when the terminal blocks serve as a
compatibilizer between the extremely non-polar PDMS and the polar DMT and BD,
and 2) the use of a high-boiling solvent (1,2,4-trichlorobenzene) during the
first phase of the reaction. Homogeneity was significantly improved in the case
of copolymers based on PCL–PDMS–PCL.
Keywords: thermoplastic elastomers, poly(ester–siloxane)s,
poly(ester–ether–siloxane)s, phase separation, compatibility.
Full Article -
PDF 123 KB
J. Serb. Chem. Soc. 72 (2)
151–157 (2007)
UDC 539.193+546.11:536.722:543.2, JSCS–3545, doi:
10.2298/JSC0702151P; Original scientific paper
Evaluation of the
intrAMolecular hydrogen bond enthalpy by means of specialized quantum chemical
methods
ALEXEI N. PANKRATOV and ALEXEI V. SHALABAY
Department of Chemistry,
(Received 17 Febryary, revised
By means of the MNDO/H, I-MNDO, MNDO/HB
andMNDO/Mmethods, the values of the enthalpy of intrAMolecular hydrogen bond
(IHB) formation for series of substances have been computed. The applicability
of these methods for a semi-quantitative estimation of the IHB enthalpy in
compounds with a planar quasicycle has been shown.
Keywords:
intrAMolecular hydrogen bond, enthalpy, quantum chemical evaluation, organic
compounds with a planar quasicycle.
Full Article -
PDF 83 KB
J. Serb. Chem. Soc. 72 (2)
159–164 (2007)
UDC 530.19*Rydberg:530.19*BuckinghAM:531.64,
JSCS– 3546, doi: 10.2298/JSC0702159L; Original scientific paper
Relationship and
discrepancies between the Extended-Rydberg and the Generalized BuckinghAM
potential energy functions
TEIK-CHENG LIM
Faculty of Engineering, Nanoscience and
Nanotechnology Initiative, 9 Engineering Drive 1,National University of
Singapore, S 117576, Republic of Singapore
(Received
This paper relates the interatomic energy
according to the Exdended-Rydberg and the Generalized BuckinghAM potential
functions by applying a Maclaurin series expansion on the latter and thereafter
comparing it with the former. In so doing, the plotted curves of these two
functions not only show equal curvature at the equilibrium state, but also
reveal a discrepancy for the finite distortion. It is shown that, when equated
at equilibrium, the Generalized BuckinghAM gives a lower energy in comparison
to the Extended-Rydberg at finite bond compression and stretching. However, the
energy difference diminishes when the interatomic distance exceeds twice that
at equilibrium. Due to such discrepancies upon comparative normalization, it
would be beneficial for computational chemists to select the appropriate
potential function for the purpose of conservative molecular modeling.
Keywords:
Extended-Rydberg, Generalized BuckinghAM, interatomic energy, Maclaurin series,
potential functions
Full Article -
PDF 89 KB
J. Serb. Chem. Soc. 72 (2)
165–181 (2007)
UDC 66.087+546.92:547.261+66.094.3,
JSCS–3547, doi: 10.2298/JSC0702165T; Original scientific paper
Effect of glassy carbon properties on the
electrochemical deposition of platinum nano-catalyst and its activity for
methanol oxidation
SANJA TERZIC, DUSAN TRIPKOVIC, VLADISLAVA M.
JOVANOVIC, AMALIJA TRIPKOVIC and ANDRZEJ KOWAL*
ICTM – Institute of Electrochemistry,
University of Belgrade, Njegoseva 12, P. O. Box 473, 11000 Belgrade, Serbia
*
(Received 31 January, revised
The effects of the properties of glassy
carbon on the deposition of platinum particles and the electrocatalytic
activity of platinum supported on glassy carbon (GC/Pt) for methanol oxidation
in alkaline and acidic solutions were studied. Platinum was potentiostatically
deposited on two glassy carbon sAMples, thermally treated at different
temperatures, which were either polished or anodicaly polarised in acid
(GCOX-AC/Pt) and in alkali (GCOX-AL/Pt). Anodic polarisation of glassy carbon,
either in alkaline or acidic solution, enhances the activity of both types of
GC/Pt electrodes for methanol oxidation. The activity of the catalysts follows
the change in the properties of the glassy carbon support upon anodic
treatment. The specific activity of the GCOX-AL/Pt electrode for this reaction
in alkali is increased only a few times in comparison with the activity of the
GC/Pt one. On the other hand, the specific activity of the GCOX-AC/Pt electrode
for methanol oxidation in acid is about one order of magnitude higher than that
of the GC/Pt electrode. The role of the substrate on the properties of catalyst
is discussed in detail.
Keywords: glassy carbon support, platinu
catalyst, electrochemical properties, methanol electrooxidation, scanning
tunneling microscopy (STM).
Full Article -
PDF 239 KB
J. Serb. Chem. Soc. 72 (2)
183–192 (2007)
UDC 66.094.3–097:547.212:547.313.2+66.023,
JSCS–3548, doi: 10.2298/JSC0702183B; Original scientific paper
An experimental study of
the partial oxidation of ethane to ethylene in a shallow fluidized bed reactor
DANICA BRZIC, DESISLAVA AHCHIEVA*, MIRKO
PEGLOW* and STEFAN HEINRICH*
Faculty of Technology and Metallurgy,
Karnegijeva 4, 11000
*Otto-von-Guericke-Universität Magdeburg, IAUT,
Universitätsplatz 2, D-39106 Magdeburg, Germany
The partial catalytic
oxidation of ethane to ethylene was investigated experimentally in a shallow
fluidized bed. The performaces of two catalyst types, pure g‑Al2O3
and V2O5/ g-Al2O3 particles 1.8 mm in diAMeter, were
analyzed. A pilot fluidized bed reactor with rectangular cross-section of 100mm´100mm
was used. The experiments were carried out under atmospheric pressure in a
dilute system under oxygen excess conditions. V2O5/g-Al2O3 showed good
catalytic performances regarding ethylene selectivity. The influence of the
temperature (in the range of 400–600 °C) and the contact time (in the range of
35 – 85 kg sm-3) on the conversion of ethane and the selectivity to
ethylene was analyzed. The highest yield of ethylene was 18 %.
Keywords: catalytic oxidation of ethane, ethylene, shallow
fluidized bed.
Full Article -
PDF 116 KB
J. Serb. Chem.
Soc. 72 (2) 193–204 (2007)
UDC
547.6+547.538.7:631.445.6(262)”322”Herceg Novi, JSCS–3549, doi:
10.2298/JSC0702193J; Original scientific paper
Summertime PAH
assembly in Mediterranean air: the Herceg Novi sAMpling station as an exAMple
VLADIMIR Z. JOVANOVIC*,
PETAR A. PFENDT*,**, and ANKA J. JOVANOVIC***
*Department of Materials
and Metallurgy, ICTM, Njego{eva 12, 11000
**Faculty of Chemistry,
***
(Received 3 November,
revised
The results of an analysis
of the total suspended particles (TSP), total solvent organic extracts (TSOE),
and polycyclic aromatic hydrocarbons (PAHs) in aerosol sAMples collected from
the atmosphere of Herceg Novi from 17th June to 15th September in 1998 and 1999
are presented. The TSP and TSOE concentrations were determined by the standard
gravimetric method, whereas the PAHs from the organic part of the aerosol were
analysed by the GC-MS method. The difference found in the TSP and TSOE contents
between the two consecutive years (before and after the bombing of Yugoslavia)
was attributed to changes in the intensity and origin of emissions from
dominant sources, specific to the summer period of this region. The content and
nature of the PAHs identified in the sAMples of 1998 and 1999 were also
different, indicating the significance of traffic as the source of PAHs, which
was of significantly lower intensity in 1999 (immediately after the war) due to
the lower influx of tourists. Factor analysis showed that the PAH distribution
at the measuring site in 1999 was largely determined by meteorological
parAMeters, mainly by the average daily temperature and wind direction. In
1998, the dominant impact on the PAH distribution was attributed to traffic,
both local and from a wider region, without an explicit impact of
meteorological parAMeters.
Keywords: PAHs, Mediterranean air polution, particulate
matter, meteorological conditions, factor analysis.
Full Article -
PDF 41 KB
Copyright
&AMp; copy; SHD 2007.
For more information contact: JSCS@tmf.bg.ac.yu