JSCS Vol 65, No. 12
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J.
Serb. Chem. Soc. 65(12) 839–846 (2000)
UDC 547.437:547.595.2
JSCS–2811
Original scientific paper
Reactivity of
cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids with
diazodiphenylmethane in aprotic solvents
JASMINA B. NIKOLIC, GORDANA S. USCUMLIC and VERA V. KRSTIC
Department of Organic Chemistry,
Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, P.
O. Box 35-03, YU-11120 Belgrade, Yugoslavia
(Received 6 July,
revised 14 September 2000)
Rate constants for the reaction of
diazodiphenylmethane with cyclohex-1-enylcarboxylic acid and
2-methylcyclohex-1-enylcarboxylic acid were determined in nine aprotic
solvents, as well as in seven protic solvents, at 30°C using the appropriate
UV-spectroscopic method. In protic solvents the unsubsituted acid displayed
higher reaction rates than the methyl-substituted one. The results in aprotic
solvents showed quite the opposite, and the reaction rates were considerably
lower. In order to explain the obtained results through solvent effects,
reaction rate constants (k) of the examined acids were correlated using
the total solvatochromic equation of the form: log k=logk0+sp*+aa+bb, where p* is the measure of the
solvent polarity, a represents the scale of the solvent hydrogen bond donor
acidities (HBD) and b represents the scale of the solvent hydrogen bond
acceptor basicities (HBA). The correlation of the kinetic data were carried out
by means of multiple linear regression analysis and the opposite effects of
aprotic solvents, as well as the difference in the influence of protic and
aprotic solvents on the reaction of the two examined acids with DDM were
discussed. The results presented in this paper for cyclohex-1-enylcarboxylic
and 2-methylcyclohex-1-enylcarboxylic acids were compared with the kinetic data
for benzoic acid obtained in the same chemical reaction, under the same
experimental conditions.
Keywords: cyclohex-1-enylcarboxylic acid,
2-methylcyclohex-1-enylcarboxylic acid, diazodiphenyulmethane, kinetic
measurements, protic and aprotic solvents.
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J.
Serb. Chem. Soc. 65(12) 847–856 (2000)
UDC: 547.826/.827:547.437
JSCS – 2812
Original scientific paper
A comparative LFER study of the
reactivity of pyridineacetic, pyridineacetic acids N-oxide and substituted
phenylacetic acids with diazodiphenylmethane in various alcohols
SASA Z. DRMANIC, BRATISLAV Z. JOVANOVIC and MILICA M.
MISIC-VUKOVIC#
Department of Organic Chemistry,
Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva
4, P. O. Box 35-03, YU-11001 Belgrade, Yugoslavia
(Received 17 July,
revised 18 September 2000)
Rate constants have been determined for the
reactions of diazodiphenylmethane (DDM) with 3- and 4-pyridineacetic acid, 3-
and 4-pyridineacetic acid N-oxide and some meta- and para-substituted
phenylacetic acids in twelve alcohols. The determined rate constants, together
with literature data, were used for calculation of Hammett r values in a series
of alcohols. Secondary s constants have been calculated for substituents in
meta and para-position of phenylacetic acids not given in literature,
and also s constants for 3N, 3N–O, 4N and 4N–O in pyridineacetic acids, in
alcohols used. The transmission of electronic effects through the phenylacetic
acid system and pyridineacetic system is compared with that in benzene and
pyridine. The multiple correlation of log k values for reaction of above
acids in 12 alcohols with group of suitable solvent parameters was very
successful.
Keywords: substituted pyridineacetic and
phenylacetic acids, protic solvents, solvent parameters, Hammett correlation.
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J.
Serb. Chem. Soc. 65 (12)857–866(2000)
UDC 623.459.46
JSCS–2813
Original scientific paper
The alcoholysis of
1,2,2-trimethylpropyl-methylfluorophosphonate
MLADJEN L. MICEVIC and SLOBODAN D. PETROVIC*
Institute of Security, YU-11000
Belgrade and
*Department of Organic Chemistry, Faculty of Technology and
Metallurgy, P.O. Box 35-03, YU-11001, Beolgrade, Yugoslavia
(Received 12 April,
revised 20 August 2000)
The alcoholysis of
1,2,2-trimethylpropyl-methylfluorophosphonate (soman) was examined with a
series of alkoxides and in corresponding alcohols: methanol, ethanol, 1-propanol,
2-propanol, 2-methoxyethanol and 2-ethoxyethanol. Soman reacts with the used
alkoxides in a second order reaction, first order in each reactant. The
kinetics of the reaction between 1,2,2-trimethylpropyl-methylfluorophosphonate
and ethanol in the presence of diethylenetriamine was also examined. A third
order reaction rate constant was calculated, first order in each reactant. The
activation energy, frequency factor and activation entropy were determined on
the basis of the kinetic data.
Keywords: decontamination, alcoholysis,
1,2,2-trimethylpropyl-methylfluorophosphonate, soman, alkoxides and
diethylenetriamine.
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J.
Serb. Chem. Soc. 65(12)867–875(2000)
UDC 678.744:66.092
JSCS–2814
Original scientific paper
The thermal degradation of
poly(iso-butyl methacrylate) and poly(sec-butyl methacrylate)
KATARINA NOVAKOVIC, LYNNE KATSIKAS and IVANKA G. POPOVIC#
Faculty of Technology and
Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Yugoslavia
(Received 17 July 2000)
The non-oxidative thermal degradation of poly(iso-butyl
methacrylate) and poly(sec-butyl methacrylate) was investigated by
studying changes in the polymer residue. Due to the different number of
b-hydrogens in their ester substituents, these two polymeric isomers behave
differently when subjected to elevated temperatures. Poly(iso-butyl
methacrylate) degrades quantitatively by depolymerisation with zip lengths of
the same order of magnitude as those of poly(methyl methacrylate). Poly(sec-butyl
methacrylate) degrades by a combined degradation mechanism of depolymerisation
and de-esterification. De-esterification becomes a significant thermolysis
route at temperatures higher than 240°C.
Keywords: poly(butyl methacrylate), isomers,
thermal degradation, mechanism, depolymerisation, de-esterification.
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J.
Serb. Chem. Soc. 65(12 )877–889 (2000)
UDC 536-33:336.4
JSCS–2815
Original scientific paper
Use of the SSF equations in the
Kojima-Moon-Ochi thermodynamic consistency test of isothermal vapour-liquid
equilibrium data
JELENA M. JELIC, ALEKSANDAR Z. TASIC, BOJAN D. DJORDJEVIC and
SLOBODAN P. SERBANOVIC
Faculty of Technology and
Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 35-03, YU-11001
Belgrade, Yugoslavia
(Received 20 July 2000)
The Kojima-Moon-Ochi (KMO) thermodynamic
consistency test of vapour–liquid equilibrium (VLE) measurements for 32
isothermal data sets of binary systems of various complexity was applied using
two fitting equations: the Redlich-Kister equation and the Sum of Symmetrical
Functions. It was shown that the enhanced reliability of the fitting of the
experimental data can change the conclusions drawn on their thermodynamic
consistency in those cases of VLE data sets that are estimated to be near the
border of consistency.
Keywords: thermodynamic consistency test,
vapour–liquid equilibria, binary system.
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J.
Serb. Chem. Soc. 65(12) 891–898 (2000)
UDC 666.19 546.817’278-31”+667.622.224,712
JSCS–2816
Original scientific paper
The devitrification of PbO-B2O3-ZnO glass
doped with Li2O
VLADIMIR D. ZIVANOVIC, NIKOLA S. BLAGOJEVIC*, SNEZANA R. GRUJIC*,
LJILJANA C. KARANOVIC** and BRANISLAVA R. BOZOVIC*
Institute for Technology of Nuclear
and Other Mineral Raw Materials, Franchet d’ Esperey 86, YU-11000 Belgrade,
*Faculty of Technology and Metallurgy, University of Belgrade,
Karnegijeva 4, YU-11000 Belgrade, and
**Faculty of Mining and Geology, Djusina 7, YU-11000 Belgrade,
Yugoslavia
(Received 13 June,
revised 13 October 2000)
In this paper the effect of the addition of Li2O on the crystallization behavior of PbO-B2O3-ZnO glass was investigated by the differential
thermal analysis (DTA) and X-ray powder diffraction (XRPD) methods. The
crystallization ability, as well as the crystalline phases which develop during
devitrification of the glass were examined. The results of DTA and XRPD
analysis showed that the addition of Li2O varies the sequence of
the crystallization as well as the phase composition of the crystalline phase.
The glasses with Li2O crystallize at a lower temperature (360°C)
with 4Li2O.4ZnO.3B2O3 as the major crystalline phase. The base PbO-B2O3-ZnO glass crystallizes at 480°C with PbO.2ZnO.B2O2 as the major crystalline phase.
Keywords: glass, devitrification, DTA, XRPD.
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J.
Serb. Chem. Soc. 65(12) 899–904 (2000)
UDC 535.51:543.253.001.8
JSCS–2817
Note
NOTE
New values of the polarity factor
MILOS D. KUKOLJAC and DUSAN K. GROZDANIC
Faculty of Technology and
Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 494, YU-11001,
Belgrade, Yugoslavia
(Received 30 December
1999, revised 26 April 2000)
New values of the polarity factor c for 96
substances are proposed. Estimation procedure is tested on the values of this
factor from the original work of Halm and Stiel.44
Keywords: polarity factor, acentric factor,
vapor pressure.
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J.
Serb. Chem. Soc. 65(12)905–914(2000)
UDC 621.352/.354:621...316
JSCS–2818
Original scientific paper
A new current line division concept
for the determination of the current distribution in electrochemical cells.
Part I. Theoretical background of the “corner weakness” effect in
electroforming
K. I. POPOV and R. M. STEVANOVIC*
Faculty of Technology and
Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 35-03, YU-11001
Belgrade and
*ICTM - Institute of Electrochemistry, Njegoseva 12, P. O. Box
815, YU-11001 Belgrade, Yugoslavia
(Received 19 April,
revised 28 August 2000)
A new approach to the determination of the
current distribution in electrochemical cells, the current line division
concept, is introduced. The new concept, based on the basic equations of
electrics and electrochemical kinetics, was employed for a theoretical
explanation of the phenomenon known in electroforming as “corner weakness”. It
was shown that this phenomenon depends on the kind of control of the deposition
process, being the largest in the case of pure ohmic control and disappearing
in the case of pure activation control.
Keywords: current distribution, current line
division, electroforming, corner weakness.
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J.
Serb. Chem. Soc. 65(12)915–922(2000)
UDC 547.263:547.281.1:541.198.2
JSCS–2819
Original scientific paper
The electro-oxidation of the
mixture of formaldehyde and 2-propanol on gold (100) and (111) single crystal
planes in alkaline medium
TANJA R. VIDAKOVIC , MILKA L. AVRAMOV-IVIC* and BRANISLAV Z.
NIKOLIC
Faculty of Technology and
Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 35-03 YU-11120
Belgrade and
*ICTM - Institute of Electrochemistry, Njegoseva 12, P. O. Box
815, YU-11000 Belgrade, Yugoslavia
(Received 30 June,
revised 19 October 2000)
The effect of formaldehyde on the oxidation of
2-propanol and vice versa on gold single crystal planes (100 and 111) was
studied. An activating effect in the reaction of the simultaneous oxidation of
2-propanol and formaldehyde was obtained on a gold (100) plane. In the case of
a gold (111) electrode, the activation effect was not obtained. It was
concluded that the adsorption of formaldehyde on the electrode surface prevents
the adsorption of poisoning species formed during the electro-oxidation of 2-propanol
on the Au(100) plane, while this is not the case on the Au(111) plane. The
different behaviour is caused by the difference in the symmetry of the surface
atoms of these two Au single-crystal planes.
Keywords: electro-oxidation, synergistic
effect, 2-propanol, formaldehyde, gold single crystal planes.
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J.
Serb. Chem. Soc. 65(12)923–933(2000)
UDC 546.47’74”:620.193:678.67
JSCS–2820
Original scientific paper
The effect of Zn-Ni sublayers on
the corrosion behaviour and thermal stability of epoxy coatings
electrodeposited on steel
VESNA B. MISKOVIC-STANKOVIC, JELENA B. BAJAT, MIODRAG D.
MAKSIMOVIC and ZORICA M. KACAREVIC-POPOVIC*
Faculty of Technology and
Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 35-03, YU-11120 Belgrade
and
*”Vinca” Institute of Nuclear Sciences, P. O. Box 522, YU-11001
Belgrade, Yugoslavia
(Received 12 July,
revised 11 September 2000)
The electrochemical and transport properties, as
well as the thermal stability of epoxy coatings electrodeposited on steel and
steel modified by Zn–Ni alloys were investigated during exposure to 3 % NaCl.
The Zn-Ni alloys were electrodeposited on steel using direct and pulse current.
From the time dependence of the pore resistance of the epoxy coating (impedance
measurements), the diffusion coefficient of water through the epoxy coating
(gravimetric liquid sorption measurements) and the thermal stability of the
epoxy coating (thermogravimetric analysis), it was shown that Zn–Ni sublayers
significantly improve the corrosion stability of a protective system based on
an epoxy coating. The values of the pore resistance were almost unchanged over
a long period of immersion time for epoxy coatings on steel modified by Zn–Ni
alloys, inidicating the great stability of these protective systems.
Keywords: electrodeposition, epoxy coatings,
Zn–Ni alloys, steel, corrosion, EIS.
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J.
Serb. Chem. Soc. 65(12)935–938(2000)
UDC 546.621–001.8:655.34
JSCS–2821
Note
NOTE
Modification
of the aluminum for making offset printing plates
PREDRAG M. ZIVKOVIC, SLOBODAN JOVANOVIC, KONSTANTIN I. POPOV and
NENAD ILIC*
Faculty of Technology and
Metallurgy, University of Belgrade, Karnegijeva 4, YU-11000 Belgrade and
*Vinca Insitute of Nuclear Sciences, YU-11000 Belgrade, Yugoslavia
(Received 19 October
1999, revised 25 August 2000)
Aluminum as the base of offset printing plates
should make good contact with wetting agents and the light sensitive layer and
should be resistant to wear and cracking. In order to achieve this, the
aluminum is roughened and eventually anodized. A thin, electrochemically
deposited chromium layer is used as the non-printing element in bimetallic
offset printing forms. Chromium shows excellent wettability and wear resistance.
The possibility of chemical deposition of chromium on aluminum from an alkaline
solution is examined in this paper. The presence of chromium was confirmed and
measured by EDAX. A difference in the spectral reflection characteristic
between chromium-treated and non-treated specimens was also detected. An
influence of a chromium layer on an aluminum surface was examined by water drop
spreading. Chromium-treated samples showed better wettability than non-treated
samples, but they are less wettable than anodized samples.
Keywords: aluminum, chromium, rouhgening,
cementation.
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J. Serb. Chem. Soc. 65(12)939–961(2000)
UDC 543.84:539.21:542.6
JSCS–2822
Original scientific
paper
Non-linear frequency response of
non-isothermal adsorption controlled by micropore diffusion with variable
diffusivity
MENKA PETKOVSKA
Department of Chemical Engineering,
Faculty of Technology and Metallurgy, Univerzity of Belgrade, Karnegijeva 4,
YU-11000 Belgrade, Yugoslavia
(Received 1 August 2000)
The concept of higher order frequency response
functions (FRFs) is used for the analysis of non-linear adsorption kinetics on
a particle scale, for the case of non-isothermal micropore diffusion with
variable diffusivity. Six series of FRFs are defined for the general
non-isothermal case. A non-linerar mathematical model is postulated and the
first and second order FRFs derived and simulated. A variable diffusivity
influences the shapes of the second order FRFs relating the sorbate
concentration in the solid phase and t he gas pressure significantly, but they
still keep their characteristics which can be used for discrimination of this
from other kinetic mechanisms. It is also shown that first and second order
particle FRFs offter sufficient information for an easy and fast estimation of
all model parameters, including those defining the system non-linearity.
Keywords: non-isothermal adsorption,
non-linear frequency response, higher order frequency response functions,
micropore diffusion, variable micropore diffusivity, parameter estimation.
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J.
Serb. Chem. Soc. 65(12)963–974(2000)
UDC 66.047:621.43.013.6
JSCS–2823
Original scientific paper
Drying of suspension and pastes in
fluidized bed of inert particles
ZELJKO B. GRBAVCIC, ZORANA LJ. ARSENIJEVIC* and RADMILA V.
GARIC-GRULOVIC*
Faculty of Technology and
Metallurgy, University of Belgrade and
*Institute of Chemistry Technology and Metallurgy, Belgrade,
Yugoslavia
(Received 11 July,
revised 19 September 2000)
A fluid bed dryer with inert particles was used
for the drying of suspensions and pastes. The effects of the operating
conditions on the dryer throughput and on the product quality were
investigated. Experiments were performed in a cylindrical column 215 mm in
diameter and 1200 mm in height with 0.925 mm diameter glass spheres as the
fluidizing media. Cineb fungicide, copper hydroxide and pure water were used as
the feed material. With respect to the main efficiency criteria, i.e., specific
water evaporation rate, specific heat consumption and specific air consumption,
a fluid bed dryer with inert particles represents a very attractive alternative
to other drying technologies. A high drying efficiency results from the large
contact area and from the large temperature difference between the inlet and
outlet air. A rapid mixing of the particles, due to aggregative fluidization
and mechanical agitation, leads to nearly isothermal conditions throughout the
bed. In our experiments, suspensions and very dense pastes were successfully
treated. Suspension and product hold-up in the bed varies between 6 and 8 % by
mass and a product with the same particle size as the raw material is obtained.
Keywords: drying, suspensions, pastes,
fluidized, inert particles.
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J.
Serb. Chem. Soc. 65(12)975(2000)
Erratum
In the paper "An Alternative Synthesis of
Clindamicin" by K. Bowden and G.P. Stevens published in J. Serb. Chem.
Soc. 65(10)(2000) 691–694 the end of the References on page 694 is omitted
during the printing process. The page 694 should read:
7. D. Brett, I. M. Downie, J. B. Lee, J. Org.
Chem. 32 (1967) 855
8. R. D. Birkenmeyer, U. S. Patent 3,475,407,
Oct 28, 1969 (C. A. 73 (1970) 25835w)
9. D. R. Hepburn, H. R. Hudson, J. Chem. Soc.
Perkin Trans. 1 (1976) 754
10. R. M. Magid, O. S. Fruchey, W. L. Johnson,
T. G. Allen, J. Org. Chem. 44 (1979) 359; R. M. Magid, B. G. Talley, S. K.
Souther, J. Org. Chem. 46 (1981) 824.
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J.Serb.Chem.Soc.
65(12)977–983(2000)
Contents of Volume 65
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J.Serb.Chem.Soc.
65(12)985-987(2000)
Subject Index
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J.Serb.Chem.Soc.
65(12)989-992(2000)
Author Index
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End of Volume 65
Copyright & copy; SHD 2000.
Last
Updated December 20, 2000.
For
more information contact: SHD@elab.tmf.bg.ac.yu