JSCS Vol 66, No. 6

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J.Serb.Chem.Soc. 66(6)359–365(2001)
UDC 547.822:543.242
JSCS–2863
Original scientific paper

The effect of solvent on the kinetics of the oxidation of 3-methyl-2,6-diphenyl-piperidin-4-one by quinolinium fluorochromate in aqueous organic media

KUPPANAGOUNDER P. ELANGO

Department of Chemistry, Gandhigram Rural Institute-Deemed University, Gandhigram 624 302, India

(Received 4 July 2000, revised 21 February 2001)
The kinetics of the oxidation of 3-methyl-2,6-diphenyl-piperidin-4-one by quinolinium fluorochromate (QFC) have been investigated in aqueous solutions of dimethyl sulphoxide, 1,4-dioxane, tert-butanol and acetone. The influence of the added co-solvent on the reactivity were analysed in the light of various simple and multiple regression equations, viz the Laidler-Eyring, Grunwald-Winstein, Swain and Kamlet-Taft equations. The obtained results showed that the solvation phenomenon plays a dominant role on the reactivity.
Keywords: kinetics, oxidation, solvent effect.
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J.Serb.Chem.Soc. 66(6)367–376(2001)
UDC 576.65:541.182
JSCS–2864
Original scientific paper

Dyeing of hydrophobic fabrics with disperse dyes

HARI RAGHAV MARADIYA and VITHAL SOMA PATEL*

V.P. and R.P.T.P. Science College, Vallabh Vidyanagar 388 120, Gujarat State, India,
*Department of Chemistry, Sardar Patel University, Vallabh Vidyanagar 388 120, Gujarat State, India

(Received 29 January 2001)
A series of disperse dyes has been synthesized by diazotisation of 2,6-dibromo-4-nitroaniline and coupled with various N-arylmaleimides. The dyes were characterized by IR spectral studies, visible absorption spectroscopy and elemental analysis. All the dyes were applied as disperse dyes on nylon, cellulose triacetate and polyester fabrics. These dyeswere found to give yellowish orange to deep brown shades with very good depth, levelness and brightness on different fabrics. The percentage dye bath exhaustion and fixation on fabrics were found to be very good. The light, washing, rubbing, perspiration and sublimation fastness properties of the dyed fabrics were found to be good to excellent.
Keywords: 2,6-dibromo-4-nitroaniline, nylon, cellulose triacetate, polyester, fixation, fastness, exhaustion.
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J.Serb.Chem.Soc. 66(6)377–383(2001)
UDC 547.458
JSCS–2865
Original scientific paper

Fine structural analysis of the fungal polysaccharide pullulan elaborated by Aureobasidium pullulans, CH-1 strain

DRAGICA JAKOVLJEVIC, MIROSLAV M. VRVIC*, MILANKA RADULOVIC and MIRJANA HRANISAVLJEVIC-JAKOVLJEVIC*

Institute of Chemistry, Technology and Metallurgy, Centre for Chemistry, Njego{eva 12, YU-11000 Belgrade and
*Faculty of Chemistry, Univeristy of Belgrade, Studentski trg 12-16, P.O. Box 158, YU-11001 Belgrade, Yugoslavia

(Received 29 December 2000)
The structure of pullulan, the extracellular a-D-glucan elaborated by the yeast-like fungus Aureobasidium pullulans, may be described as a linear a-D-glucan consisting of maltotriosyl repeat units connected terminally by (1->6)-a-D-glucosidic bonds. Occasionally some of maltotriosyl residues are replaced by higher oligosaccharide units, most frequently with maltotetraosyl residues. Using the susceptibility of pullulan CH-1 (obtained from strain CH-1 of Aureobasidium pullulans) to hydrolysis catalysed by porcine alpha-amylase, the polysaccharide was cleaved and the fragments obtained fractionated by gel-permeation chromatography. The heterogenous size of the fragments indicates that there is no apparent regular distribution of tetrasaccharide units in the pullulan chain. Enzymatic digestion of pullulan CH-1 using pullulanase, followed by gel-permeation chromatography of the resulting digest confirmed these results as did preparative paper chromatography and CI mass spectrometry of the separated components, i.e., that maltotetraosyl units (about 7 %) are building units of pullulan CH-1.
Keywords: Aureobasidium pullulans, polysaccharide, pullulan, amylolysis, pullulanolysis.
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J.Serb.Chem.Soc. 66(6)385–396(2001)
UDC 549.623.63:541.183
JSCS–2866
Original scientific paper

Sorption characteristics of paper produced from sepiolite

MIROSLAVA DOJCINOVIC*, MILAN MITROVIC*, MILJENKO MARTIC*, VERA VUCELIC* and DUSAN VUCELIC*,**

*Institute of General and Physical Chemistry, Studentski trg 12, P.O. Box 551, YU-11001 Belgrade, and
**Faculty of Physical Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 138, YU-11001 Belgrade, Yugoslavia

(Received 10 January 2001)
Paper laboratory-produced from sepiolite, Goles-Serbia was studied to determine its sorption characteristics for nitric oxides, water vapor, and ammonia. The paper adsorbed high percentages of nitric oxides and ammonia was stoichiometrically chemisorbed on paper saturated with NO2 and H2O. Infrared spectroscopy showed that the sorption of nitric oxides and ammonia does not destroy the crystal lattice of sepiolite, which was confirmed by XRD-analysis. Sorption of both nitric oxides and ammonia occurred by zeolitic water inside the structural channels of sepiolite. Pressure swing adsorption (PSA) or temperature swing adsorption (TSA) cycles can be repeated many times, in the case of NOx and NH3.
Keywords: ammonia, IR, nitric oxides, sepiolite, sorption, XRD.
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J.Serb.Chem.Soc. 66(6)397–401(2001)
UDC 547.458:65
JSCS–2867
Short communication

SHORT COMMUNICATION
Specific refractive index increments of inulin

GORAN S. NIKOLIC, MILORAD D. CAKIC and LJUBOMIR A. ILIC*

Faculty of Technology, University of Ni{, Bulevar Oslobodjenja 124, YU-16000 Leskovac and
*Pharmaceutical and Chemical Industry "Zdravlje", YU-16000 Leskovac, Yugoslavia

(Received 14 July 2000, revised 28 February 2001)
The specific refractive index increments (dn/dc) of inulin in water, at 25°C, were measured at different wavelengths (436, 546 and 589 nm) using a BP-differential refractometer. The dn/dc at the operating wavelength (633 nm) of the laser light scattering photometer was calculated by an approximate method. This value can be used to determine the absolute molar mass and the second virial coefficient of inulin by light scattering photometry.
Keywords: inulin, specific refractive index increment.
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J.Serb.Chem.Soc. 66(6)403–409(2001)
UDC 541.183:547.914
JSCS–2868
Note

N O T E
On the adsorbed mass of polymers on surfaces

GEORGIOS K. STRATOURAS

Kalypsous 15, Akropolis, Nicosia, Cyprus-2014

(Received 8 December 2000, revised 6 March 2001)
It is shown that for ideal polymers interacting with a surface via the pseudopotential of a delta function, the number of contacts between the monomer units and the surface as a function of concentration cb is a dependence of the form acb/(1–bcb). The architecture of the polymer, the degree of polymerization, the interaction energy between a monomer unit and the surface, the area of the surface and the monomer length are embodied in the parameters a and b. The above dependence of the adsorbed mass of a polymer on the concentration is confirmed by the experimental results of Takahashi and his collaborators. For linear polystyrene of molecular weight 134×105,interacting with a chrome plate, the parameters a and b are, respectively, about equal to (89938/273) ×10-6 m and (–19300/273) m3 kg-1.
Keywords: adsorbed mass, polymer, linear, cyclic, A-B diblock copolymer.
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J.Sehem.Soc. 66(6)411–418(2001)
UDC 553.52:548.2
JSCS–2869
Original scientific paper

The growth of sapphire single crystals

ALEKSANDAR GOLUBOVIC, SLOBODANKA NIKOLIC, STEVAN DJURIC* and ANDREJA VALCiC**

Institute of Physics, Pregrevica 118, P.O. Box 57, YU-11001 Belgrade,
*Faculty of Mining and Geology, Djusina 7, P.O. Box 162, YU-11000 Belgrade and
**Faculty of Technology and Metallurgy, Karnegijeva 4, YU-11000 Belgrade, Yugoslavia

(Received 8 November 2000, revised 14 March 2001)
Sapphire (Al2O3) single crystals were grown by the Czochralski technique both in air and argon atmospheres. The conditions for growing sapphire single crystals were calculated by using a combination of Reynolds and Grashof numbers. Acritical crystal diameter dc = 20 mm and the critical rate of rotation wc = 20 rpm were calculated from the hydrodynamics of the melt. The value of the rate of crystal growth was experimentally found to be 3.5 mm/h. According to our previous experiments, it was confirmed that three hours exposures to conc. H3PO4 at 593 K was suitable for chemical polishing. Also, three hours exposure to conc.H3PO4 at 523 K was found to be a suitable etching solution. The lattice parameters a = 0.47573 nm and c = 1.29893 nm were determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.
Keywords: Czochralski technique, sapphire, growth, single crystal, etching.
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J.Serb. Chem.Soc. 66 (6)419–427(2001)
UDC 546.19.539.1.08
JSCS–2870
Original scientific paper

A new technique of arsenic determination based on electrolytic arsine generation and atomic absorption spectroscopy

MIRJANA M. SEVALJEVIC, SLAVKO V. MENTUS* and NIKOLA J. MARJANOVIC**

Technological Ecological Center, Petra Drap{ina 15, Zrenjanin,
*Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12, YU-11000 Belgrade and
**Faculty of Technology, University of Novi Sad, Cara Lazara 1, YU-21000 Novi Sad, Yugoslavia

(Received 20 November 2000, revised 14 February 2001)
Amethod for the determination of traces of arsenic in food has been developed based on electrolytic arsine generation and atomic absorption spectroscopy detection.
The essence of the method is the addition of copper and tin salts to the electrolyte solution, enabling a fast and effective arsine evolution. The advantage of this method lies in the fact that it enables the simultaneous concentration of heavymetals, such as cadmium and lead, on cathode. The applicability of themethod was illustrated by determining the arsenic content in some food samples based on vegetable oils and by comparing the results with those obtained by the classical technique of chemical hydriding with sodium tetrahydroborate.
Keywords: arsine generation, atomic absorption spectroscopy, electrolysis, trace determination, diffusion rate constants.
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