JSCS Vol 67, No. 7
Adobe Acrobat version
|
These articles were
created using Adobe Acrobat and some were compressed using WinZip |
To download the latest |
|
|
To download the text of the whole issue
click here |
|
Impresum |
|
J.Serb.Chem.Soc.
67(7)465–471(2002) |
To download this article click here 95 KB |
Antimalarial peroxides: the first
intramolecular 1,2,4,5-tetraoxane
DEJAN OPSENICA, GABRIELLA POCSFALVI*, WILBUR K. MILHOUS** and
BOGDAN A. SOLAJA***
Institute of Chemistry, Technology
and Metallurgy, Belgrade, Yugoslavia,
*Centro di Spettrometria di Massa Proteomica e Biomoleculare,
Istituto di Scienze dell’Alimentazione, Consiglio Nazionale delle Ricerche,
Avellino, Italy,
**Division of Experimental Therapeutics, Walter Reed Army
Institute of Research, Washington, DC 20307-5100, USA and
***Faculty of Chemistry, University of Belgrade, P. O. Box 158,
YU-11001 Belgrade, Yugoslavia
(Received
28 February 2002)
An
intramolecular steroidal 1,2,4,5-tetraoxane has been synthesised in six steps
starting from methyl 3-oxo-7a,12a-diacetoxy-5b-cholan-24-oate. The synthesised
1,2,4,5-tetraoxane has moderate in vitro antimalarial activity against P.
falciparum strains (IC50 (D6) = 0.35 mg/mL; IC50 (W2) =
0.29 mg/mL).
Keywords:
tetraoxane, malaria, peroxide, steroid, intramolecular.
|
J.Serb.Chem.Soc.
67(7)473–480(2002) |
To download this article click here 80 KB |
Synthesis of monoketo and
monohydroxy eicosanoic acids and esters with substituents at odd–numbered (3-13)
carbons
HÜLYA ÇELÍK
Department of Chemistry, Faculty of
Engineering, Istanbul University, 34850 Avcilar, Istanbul, Turkey; e-mail:
hcelik@istanbul.edu.tr
(Received
28 December 2001, revised 8 April 2002)
In
this study, monoketo and monohydroxy eicosanoic acids and their methyl esters
with the position of the substituent on odd numbered carbon atoms from 3 to 13
were synthesized with high purity. Furthermore, the semicarbazone and anilide
derivatives of the obtained keto acids were prepared. They were characterized
by TLC, IR and 1H-NMR spectroscopy and their physical and chemical properties were
established.
Keywords:
monoketo, monohydroxy, eicosanoic acid methyl ester.
|
J.Serb.Chem.Soc.
67(7)481–487(2002) |
To download this article click here 82 KB |
Influence of the stationary and
mobile phase composition on solvent strength parameter eo and SP
system parameter in NP column chromatography
T. J.JANJIC, G. VUCKOVIC and M. B. CELAP
Faculty of Chemistry, University of
Belgrade, P. O. Box 158, YU-11001 Belgrade, Yugoslavia
(Received
31 January 2002)
It
is shown that SP system parameters, previously used for the linearization of
log k values in RP chromatography, can also be used in NP
chromatography. A very good linear correlation between SP parameter and
the earlier described Snyder solvent strength parameter has been established.
It was also found that the phase equilibrium constant K is independent
of the polarity and concentration of the more polar component of binary solvent
mixtures.
Keywords:
NP chromatography, SP parameter, solvent strength parameter eo.
|
J.Serb.Chem.Soc. 67(7)489–497(2002) |
To download this article click here 103 KB |
Study of sepiolite from Goles
(Kosovo, Yugoslavia). I. Sorption capacity
MARINA RADOJEVIC, VIDOJKO JOVIC*, and DRAGOMIR VITOROVIC**
Institute of General and Physical
Chemistry, P. O. Box 551, Studentski trg 12, YU-11000 Belgrade,
*Faculty of Mining and Geology, Djusina 7, YU-11000 Belgrade and
**Center of Chemistry –ICTM, Njegoseva 12, YU-11000 Belgrade,
Yugoslavia
(Received
8 February 2002)
The
sorption of molecules of different size and polarity (water, n-hexane,
isooctane, benzene, toluene, cyclohexane, carbon tetrachloride, isopropanol,
isobutanol, methanol, ethanol) by sepiolite from Goles, i.e. from the
biggest to-date known Yugoslav deposit, was studied in this work. The BET
surface area observed with different sorbates varied from 227 to 314 m2/g, due to
only partial migration of sorbate molecules into the pores or to imperfect
packing of the sorbate molecules. The value of the outer surface area suggested
that the average thickness of the fibers of Goles sepiolite was approximately
15 nm.
Keywords:
sepiolite, Goles, sorption capacity, BET surface area, alcohols, alkanes,
aromatics, carbon tetrachloride.
|
J.Serb.Chem.Soc.
67(7)499–506(2002) |
To download this article click here 102 KB |
Study of sepiolite from Goles
(Kosovo, Yugoslavia). II. Acid activation
MARINA RADOJEVIC, VIDOJKO JOVIC*, DRAGOMIR KARAULIC and DRAGOMIR VITOROVIC**
Institute of General and Physical
Chemistry, P. O. Box 551, Studentski trg 12, YU-11000 Belgrade,
*Faculty of Mining and Geology, Djusina 7, YU-11000 Belgrade and
**Center of Chemistry –ICTM, Njegoseva 12, YU-11000 Belgrade,
Yugoslavia
(Received
8 February 2002)
The
changes in the pore structure and adsorption properties of sepiolite from Gole{
resulting from treatment with 4 M HCl for various periods of time were
investigated. The BET method specific surface areas, pore volumes and f –
plots were determined by nitrogen adsorption. The surface area progressively
increased during the 70 hours of acid treatment, when a maximum was attained.
The differences in the adsorption properties of the original and the acid
treated sepiolite were evaluated by comparison of adsorption isotherms obtained
with benzene, n-hexane, methanol and isooctane. The enhanced adsorption
of isooctane was of great interest, since the sorption of this compound on
natural sepiolites is generally very limited. The results suggest that chemical
treatment of sepiolite with 4 M HCl for 70 h produces an adsorbent of optimal
porosity and other adsorption properties.
Keywords:
sepiolite, Goles, acid activation, surface area, pore volume, f – plot,
adsorption.
|
J.Serb.Che.Soc.
67(7)507–521(2002) |
To download this article click here 153 KB |
Extraction and separation of
titanium(IV) with D2EHPA and PC-88A from aqueous perchloric acid solutions
RAJEEV K. SINGH and PURSHOTTAM M. DHADKE
Inorganic Chemistry Laboratory,
Applied Chemistry Division, Department of Chemical Technology, University of
Mumbai, Matunga, Mumbai – 400 019, India
(Received
20 August 2001, revised 1 March 2002)
The
liquid-liquid extraction of Ti(IV) from perchlorate media using,
di(2-ethylhexyl) phosphoric acid (D2EHPA) and 2-ethylhexyl prosphonic acid
mono-2-ethylhexyl ester (PC-88A) in toluene as the extractant was studied.
Quantitative extraction of Ti(IV) was observed in the lower acidity range of
0.01 to 0.1 mol dm-3 with 0.003 mol dm-3 D2EHPA and
0.01 mol dm-3 PC-88A in toluene, respectively, and in the higher acidity range
of 9.0 to 10.0 mol dm-3 with 0.1 mol dm-3 D2EHPA and
PC-88A in toluene. Ti(IV) was completely stripped from the metal loaded organic
phase of both the extractants with 3 % H2O2 in 1 M H2SO4 and
determined spectrophotometrically. The stoichiometry of the extracted species
was determined on the basis of slope analysis. The extraction in the lower
acidity range was found to proceed by a cation-exchange mechanism with the
extracted species being TiOR2·2HR, while
in the higher acidity range it was by solvation with the extracted species
being Ti(OH)3ClO4·4HR. Separation of Ti(IV) was also carried out from some
associated metals like Fe(III), Al(III), V(V), Ce(IV), Mg(II) and Mn(II). The
developed methods were extended for the determination of Ti(IV) in real samples
like ilmenite, magnetite and red mud in order to show the practical utility of
the extractants.
Keywords:
extraction, titanium, separation, D2EHPA, PC-88A and stripping.
|
J.Serb.Chem.Soc.
67(7)523–530(2002) |
To download this article click here 90 KB |
Synthesis and characterization of
2,3,13,14-tetramethyl (ethyl or p-tolyl)-1,4,12,15-tetraazacyclodocosa-1,3,12,14-tetraene
complexes of Mg(II), Ca(II), Sr(II) and Ba(II)
RAGHU N. PRASAD and SEEMA GUPTA
Department of Chemistry, University
of Rajasthan, Jaipur 302004, India
(Received
28 January 2002)
2+2
Cyclocondensation of 1,7-diaminoheptane with a-diketones, viz.
2,3-butanedione, 3,4-hexanedione or 4,4’-dimethylbenzil, in the presence of Mg2+, Ca2+, Sr2+ and Ba2+ ions as
templates yields a series of complexes of the type [ML(X2)] (where L
= N4 macrocycle having a 22-membered ring and X = Cl or NCS). The
resulting complexes were characterized by elemental analysis, conductance
measurements and IR and 1H-NMR spectral studies.
Keywords:
macrocyclic complexes, alkaline earth metal complexes, conductances, IR
spectra, NMR spectra.
|
J.Serb.Chem.Soc.
67(7)531–546(2002) |
To download this article click here 153 KB |
Surface reconstruction during the
adsorption/desorption of OH- species onto Cu(111) and Cu(100) in 0.1 M NaOH solution
V. D. JOVIC and B. M. JOVIC
Department of Materials
Engineering, Drexel University, Philadelphia, PA 19104, USA
(Received
1 April 2002)
The
process of adsorption/desorption of OH- species
onto Cu(111) and Cu(100) in 0.1 M NaOH solution has been investigated by cyclic
voltammetry and the potentiostatic pulse technique. Investigation of the
electrochemical behavior of the Cu(100) face in 0.1 M NaOH solution was
performed for the first time in this work. It was shown that the
adsorption/desorption of OH- species occurs in the potential
range between –1.13 V vs. SHE and – 0.83 V vs. SHE forming an
adsorbate of low coverage. It was shown that in 0.1 M NaOH solution
irreversible surface reconstruction of the Cu(111) face occurs as a consequence
of the adsorption/desorption of OH- species.
The original surface cannot be restored even if the electrode is exposed to
potentials more positive than – 0.53 V vs. SHE for some time. If this
time is, in the case of repetitive pulse experiments, equal or smaller than 10
s reconstruction does not occur. Adsorption of OH- species
takes place in the potential range more negative than – 0.6 V vs. SHE
only on reconstructed surfaces. For this process to occur onto
non-reconstructed, original Cu(111) surfaces, higher overpotentials are needed.
Keywords:
Cu(111), Cu(100), OH- adsorption, surface reconstruction.
Copyright & copy; SHD 2002.
Last
Updated September 2, 2002.
For
more information contact: SHD@elab.tmf.bg.ac.yu