JSCS Vol 66, No. 8
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J.Serb.Chem.Soc.
66(8) 499–505(2001)
UDC 547.918
JSCS–2879
Original scientific paper
The Ferrier rearrangement as the
key step in the synthesis of C7–C16-alkyl
2,3-dideoxy glucosides from glucose and C7–C16-alkanols
STANIMIR KONSTANTINOVIC, JASMINA PREDOJEVIC, SVETISLAV GOJKOVIC*,
VLADIMIR PAVLOVIC** and JÁNOS CSANÁDI***
Department of Chemistry, Faculty of
Science, University of Kragujevac, P. O. Box 60, YU-34000 Kragujevac, E-mail:
konstan@eunet.yu,
*Institute for Chemistry, Technology and Metallurgy, Njegoseva 12,
YU-11000 Belgrade,
**Faculty of Chemistry, University of Belgrade, P. O. Box 158,
YU-11001 Belgrade and
***Institute of Chemistry, Faculty of Science, University of Novi
Sad, Trg Dositeja Obradovica 3, YU-21000 Novi Sad, Yugoslavia
(Received 8 March 2001)
The Ferrier rearrangment was used as the key
step in the synthesis of C7–C16-alkyl 2,3-dideoxy
glucosides from glucose and C7–C16-alkanols.
Keywords: synthesis of C7–C16-alkyl 2,3-dideoxy glucosides, Ferrier
rearrangement.
To download this article click here (101 KB pdf file)
J.Serb.Chem.Soc.66
(8)507–516(2001)
UDC 547.554
JSCS – 2880
Original scientific paper
Synthesis and investigation of
solvent effects on the ultraviolet absorption spectra of
5-substituted-4-methyl-3-cyano-6-hydroxy-2-pyridones
DUSAN Z. MIJIN, GORDANA S. USCUMLIC and NATASA V. VALENTIC
Department of Organic Chemistry,
Faculty of Technology and Metallurgy, University of Belgrade, P. O. Box 3503,
YU–11001, Belgrade, Yugoslavia
(Received 5 April,
revised 15 May 2001)
A number of
5-substituted-4-methyl-3-cyano-6-hydroxy-2-pyridones from cyanoacetamide and
the corresponding alkyl ethyl acetoacetates were synthesized according to
modified literature procedures. The alkyl ethyl acetoacetates were obtained by
the reaction of C-alkylation of ethyl acetoacetate. An investigation of the
reaction conditions for the synthesis of 4-methyl-3-cyano-6-hydroxy-2-pyridone
from cyanoacetamide and ethyl acetoacetate in eight different solvents was also
performed. The ultraviolet absorption spectra of synthesized pyridones were
measured in nine different solvents in the range 200–400 nm. The effects of
solvent polarity and hydrogen bonding on the absorption spectra are interpreted
by means of linear solvation energy relationships using a general equation of
the form n = n0 + sp* + aa + bb, where p* is a measure of the solvent polarity, a is
the scale of the solvent hydrogen bond donor acidities and b is the
scale of the solvent hydrogen bond acceptor basicities.
Keywords: alkylation, ethyl acetoacetate,
alkyl ethyl acetoacetates synthesis, 5-substituted-4-methyl-3-cyano-6-hydroxy-2-pyridones,
spectroscopy, cyclization, ultraviolet absorption spectra, solvent effects,
linear solvation energy relationships.
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J.Chem.Soc.Soc.
66(8)517–521(2001)
UDC 546.271
JSCS – 2881
Original scientific paper
On the Klemm model for bistability
of mixtures of interacting enantiomers
IVAN GUTMAN
Faculty of Science, University of
Kragujevac, P. O. Box 60, YU-34000 Kragujevac, Yugoslavia
(Received 19 April 2001)
The solution of the Klemm model for spontaneous
chiral stereoselection has been obtained. It is shown that a system whose
time-evolution is described by the Klemm model, independently of the initial
value of the enantiomeric excess, always reaches a racemic terminal state. In a
system described by the Klemm model bistability never occurs.
Keywords: chirality, homochirality,
bistability, Klemm model, Frank model.
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J.Serb.Chem.Soc.
66(8)523–534(2001)
UDC 549.521.4
JSCS – 2882
Original scientific paper
Thermodynamical consideration of
the synthesis of solid AlN from thermal plasma
JELENA RADIC-PERIC and NIKOLA PEKAS
Faculty of Physical Chemistry,
University of Belgrade, Studentski trg 12-16, P. O. Box 137, YU-11001 Belgrade
(Received 30 March 2001)
The synthesis process of solid AlN in thermal
plasmas was investigated theoretically by computing the equilibrium composition
of the gas mixture involving nitrogen and various amounts of aluminum, oxygen
and hydrogen for the temperature range between 1000 and 5500 K. The results
obtained by treating the plasma as a single-gas system were combined with those
which take into account the presence of solid AlN and liquid Al, to find the
optimal conditions for the deposition of solid AlN. The factors determining the
efficiency of this process are discussed.
Keywords: plasma synthesis, AlN synthesis,
thermodynamics of AlN.
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J.Serb.Chem.Soc.
66(8)535–542(2001)
UDC 546.271
JSCS – 2883
Original scientific paper
Some problems connected with boron
determination by atomic absorption spectroscopy and the sensitivity improvement
MIRJANA S. PAVLOVIC, JELENA J. SAVOVIC# and MOMIR MARINKOVIC
Vinca Instititute of Nuclear
Sciences, Laboratory of Physical Chemistry, P.O. Box 522, YU-11001 Belgrade,
Yugoslavia
(Received 13 March 2001)
Two atomizers were compared: an N2O–C2H2 flame and a stabilized
U-shaped DC arc with aerosol supply. Both the high plasma temperature and the
reducing atmosphere obtained by acetylene addition to the argon stream
substantially increase the sensitivity of boron determination by atomic
absorption spectroscopy (AAS) when the arc atomizer is used. The results were
compared with those for silicon as a control element. The experimental
characteristic concentrations for both elements were compared with the computed
values. The experimentally obtained characteristic concentration for boron when
using the arc atomizer was in better agreement with the calculated value. It
was estimated that the influence of stable monoxide formation on the
sensitivity for both elements was about the same, but reduction of analyte and
formation of non-volatile carbide particles was more important for boron, which
is the main reason for the low sensitivity of boron determination using a flame
atomizer. The use of an arc atomizer suppresses this interference and
significantly improves the sensitivity of the determination.
Keywords: boron, atomic absorption
spectroscopy, characteristic concentration, DC arc plasma.
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J.Serb.Chem.Soc.
66(8)543–553(2001)
UDC 546.634
JSCS – 2884
Original scientific paper
Complexes of light lanthanides with
2,3-dimethoxybenzoic acid
WIESLAWA FERENC and AGNIESZKA WALKÓW-DZIEWULSKA
Faculty of Chemistry, Maria
Curie-Sklodowska University, Pl. 20-031 Lublin, Poland
(Received 7 February,
revised 5 May 2001)
The complexes of light lanthanides with
2,3-dimethoxybenzoic acid of the formula: Ln(C9H9O4)3, where Ln = La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III)
and Gd(III) have been synthesized and characterized by elemental analysis, IR
spectroscopy, thermogravimetric studies, as well as X-ray and magnetic
measurements. The complexes have colours typical for Ln3+ ions (La, Ce, Eu, Gd–white, Sm–cream, Pr–green, Nd–violet). The
carboxylate group in these complexes is a bidentate, chelating ligand or a
tridentate chelating and bridging one. They are crystalline compounds
characterized by low symmetry. On heating in air to 1173 K, the
2,3-dimethoxybenzoates of the light lanthanides decompose in various ways. The
complexes of Ce(III), Pr(III), Sm(III), Eu(III) and Gd(III) decompose directly
to oxides of the respective metals while those of La(III) and Nd(III) via the
intermediate formation of La2O2CO3 and Nd2O2CO3. The solubilities of the 2,3-dimethoxybenzoates
of the light lanthanides in water at 293 K are in the orders of 10-3 – 10-2 mol dm-3. The magnetic moments
were determined in the range 4.2–298 K and the complexes are found to obey the
Curie-Weiss law.
Keywords: 2,3-dimethoxybenzoates, light
lanthanides, thermal stability, magnetic moments.
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J.Serb.Chem.Soc.
66(8)555–561(2001)
UDC 541.183.1:553.67:632.4 aflatoxin B1
JSCS – 2885
Original scientific paper
The effect of exchangeable cations
in clinoptilolite and montmorillonite on the adsorption of aflatoxin B1
MAGDALENA TOMASEVIC-CANOVIC, ALEKSANDRA DAKOVIC, VESNA MARKOVIC
and DRAGAN STOJSIC*
Institute for Technology of Nuclear
and Other Mineral Raw Materials, P. O. Box 390, YU-11001, Belgrade and
*VMA - Institute for Hygiene, YU-11000, Belgrade, Yugoslavia
(Received 25 January
2001)
The adsorption of aflatoxin B1 (AFB1) by cation-exchanged clinoptilolite zeolitic tuff and
montmorillonite was investigated at 37°C and pH 3.8 from an aqueous electrolyte
having a composition similar to that of gastric juices of animals. Both
minerals were exchanged from the natural form to the sodium form and then to
the Cu2+, Zn2+ and Co2+-rich forms. The cation exchange was different for the different
cations, but in all cases the exchanges were larger on montmorillonite than on
clinoptilolite. The degree of exchange on montmorillonite was 76 % for copper
(from a total of CEC 0.95 meq/g, Cu2+ –0.73 meq/g) and 85 %
for zinc and cobalt. Under the same conditions (concentration, temperature, pH,
contact time), the degree of exchange on zeolitic tuff was 12 % for Cu2+ (from a total CEC of 1.46 meq/g, Cu2+ –0.17 meq/g), 8 % for Zn2+ and 10 % for Co2+. Both groups of mineral adsorbents showed high AFB1 chemisorption
indexes (ca). For the montmorillonite forms, ca ranged from 0.75 for the Cu-exchanged montmorillonite to 0.89 for
the natural Ca-form, 0.90 for the Zn-exchanged form and 0.93 for the
Co-exchanged montmorillonite. The adsorption of AFB1 on the different exchanged
forms of clinoptilolite gave similar values of ca for the Cu and Ca forms (0.90) and values of 0.94 and 0.95 for
the Zn- and Co-exchanged form. The impact of the mineral adsorbents on the
reduction of essential nutrients present in animal feed (Cu, Zn, Mn and Co)
showed that the Ca-rich montmorillonite had a higher capability for the
reduction of the microelements than the Ca-rich clinoptilolite.
Keywords: clinoptilolite, montmorillonite,
cation exchange, adsorption, aflatoxins.
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J.Serb.Chem.Soc.
66(8)563–569(2001)
UDC 538.556
JSCS – 2886
Original scientific paper
A study of periodic current
oscillations of iron in nitric acid solutions
NAITAO CUI*, SHIYONG ZHAO*, CHAO
WANG*** and SHENHAO CHEN*,**
*Chemistry Department, Shandong
University, Jinan 250100, P. R. China,
**State Key Laboratory for Corrosion and Protection, Shenyang
110015, P. R. China and
***Chemistry Department, Xuzhou Teachers’ University, Xuzhou
221009, P. R. China
(Received 4 April 2001)
The periodic current oscillations of Fe/HNO3 are presented in this paper. The effects of HNO3 concentration and imposed potential were investigated. The
dropping method was used to change the local pH of the Fe/electrolyte
interface, creating environments that favor the occurrence of current
oscillations. Some interesting results were obtained and an explanation of the
current oscillations is suggested.
Keywords: iron, nitric acid, current
oscillations, electrodissolution.
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Copyright & copy; SHD 2001.
Last
Updated Seprember 20, 2001.
For
more information contact: SHD@elab.tmf.bg.ac.yu