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Search Results: 1 - 10 of 163 matches for " Milutin Milosavljevi? "
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New method for synthesis of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropylthiocarbamates by oxidation of ammonium salt of xhantogenic acid
Milisavljevi? Smiljka S.,Marinkovi? Aleksandar D.,MilosavljeviMilutin M.
Hemijska Industrija , 2010, DOI: 10.2298/hemind100527049m
Abstract: A synthesis of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates by oxidation of ammonium salt of ethyl and isopropylxanthogenic acid in a presence of sodium hypochlorite and hydrogen peroxide were performed. Ammonium salt of ethyl and isopropylxanthogenic acid was obtained by the reaction of alkylammonium sulfate and sodium ethyl and isopropyl xanthate. Studies on a dependence of N-ethyl-O-isopropylthiocarbamate yield and purity with respect to reaction parameters (reaction time, molar ratio of oxidant and ethylamonium salt of isopropylxanthogenic acid) were performed. Optimal reaction conditions for synthesis of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates were established. Synthesized compounds have been fully characterized by FTIR, 1H NMR and MS data, while purity has been determined by GC method. A plausible pathway for the N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates synthesis, in the presence of the oxidative agents sodium hypochlorite and hydrogen peroxide, was proposed. The presented synthetic methods has been developed at laboratory and applied at semi-industrial level. The developed optimal method provides a powerful and versatile method for the preparation of N-alkyl and N,N-dialkyl-O-ethyl and O-isopropyl thiocarbamates. This new optimized method offer several benefits, namely, simple operation, mild reaction conditions, bypass of hazardous organic solvents, moderately toxic and inexpensive reagents, and also short reaction times and high product yields.
Synthesis of N-and N,N-dialkyl-S-alkylthiolcarbamates by the rearrangement of N-and N,N-dialkyl-O-thioncarbamates
MilosavljeviMilutin M.,Marinkovi? Aleksandar D.,?or?evi? Sini?a
Hemijska Industrija , 2006, DOI: 10.2298/hemind0602027m
Abstract: A series of N- and N,N-dialkyl-S-alkylthiolcarbamates were synthesized by the rearrangement of N- and N,N-dialkyl-O-alkylthioncarbamates in the presence of diethyl sulfate. The synthesis of some compounds without catalyst was also performed. The compounds were identified by IR, 1H NMR and MS spectroscopic methods. The starting thioncabamates were obtained from the corresponding xanthogenacetates and amines and their structures were also confirmed by IR, 1H NMR and MS data. Some of the thiolcarbamates were characterized for the first time in the literature.
Kinetic study of the reaction between sodium ethyl xanthogenacetate and alkylamine
Milutin Milosavljevi,Sini?a ?or?evi?,Slavica Ra?i?
Chemical Industry and Chemical Engineering Quarterly , 2007,
Abstract: N/A
THE OPTIMIZATION OF ZINC DIALKYLDI-THIOCARBAMATES SYNTHESIS AND DETERMINATION OF THEIR ANTIOXIDANT ACTIVITY
Aleksandar D. Marinkovi?,Milutin Milosavljevi,Dragan Milenkovi?,Goran Ivanovi?
Chemical Industry and Chemical Engineering Quarterly , 2008,
Abstract: A two-step optimized laboratory synthetic method of zinc dialkyldithiocarbamates is presented. In the course of the first phase, a sodium salt of dialkyldithiocarbamic acid has been synthesized from the dialkylamines, carbon disulfide and sodium hydroxide. The synthesis of zinc dialkyldithiocarbamates was achieved by the precipitation from sodium dialkyldithiocarbamic acid by zinc sulfate under the optimized conditions. The synthesized products have been characterized by FTIR, 1H and 13C NMR, AAS spectroscopic methods, as well as by elemental analysis and melting points. Kinetic studies of the motor oil oxidation inhibited by synthesized compounds have been tested using a standard method.
Influence of gelatin on corrosion behavior of copper in acid media
Todorovi? Dragi?a A.,Milenkovi? Dragan D.,MilosavljeviMilutin M.,Markovi? Dragan A.
Hemijska Industrija , 2012, DOI: 10.2298/hemind110616089t
Abstract: This paper presents the results of gelatin and benzotriazole (BTA) inhibitory action on copper in the acid medium by the method of weight loss. The investigation was carried out in the citric acid solution (1, 5 and 20%) at the temperature of 293 K. Under such conditions, the gelatin showed higher efficiency of corrosion protection in comparison to BTA. The results, obtained through the Gibbs and Langmuir adsorption isotherm, show that gelatin adsorption on copper surface obey the Langmuir adsorption isotherm model, as well as that the adsorption is a spontaneous process. The polarization measurements show the potential of full passivation shift towards more negative values, and the increase of corrosion current in both cases but being more pronounced with the BTA. The results obtained in this paper indicate that the inhibition gelatin can be used as the BTA substitute for the copper corrosion protection.
Comparative analysis of oxidative synthesis of N-alkyl, N,N-dialkyl and N-cykloalkyl-O-isobutyl thioncarbamate
Sovrli? Milica ?.,MilosavljeviMilutin M.,Marinkovi? Aleksandar D.,?ukanovi? Jasmina S.
Hemijska Industrija , 2011, DOI: 10.2298/hemind110504038s
Abstract: A optimized synthesis of N-alkyl, N,N-dialkyl- and N-cycloalkyl-O-isobutyl thioncarbamates by aminolysis of sodium isobutylxanthogenic acid (NaiBXAc) and primary, secondary and cycloalkyl amines was developed at laboratory scale and applied at semi-industrial level. Studies on dependence of N-n-propyl-O-isopropylthiocarbamate yield and purity with respect to reaction parameters: reaction time and molar ratio of n-propylamine and NaiBXAc, were performed. In such way, optimal reaction conditions for synthesis of N-alkyl, N,N-dialkyl- and N-cycloalkyl-O-isobutyl thioncarbamates, by aminolysis of NaiBXAc, were established. Also, comparative results of thioncarbamates synthesis starting from potassium isobutyl xanthate (KiBX) and corresponding amines in presence of different oxidants: hydrogen peroxide, sodium hypochlorite and new oxidative agent potassium peroxodisulfate were evaluated. Synthesized compounds have been fully characterized by FTIR, 1H and 13C NMR and MS data, elemental analysis and purity have been determined by gas chromatographic method (GC). According to our knowledge, ten synthesized thioncarbamates are for the first time characterized. Synthesized compounds could be used as selective reagents for flotation of copper and zinc ores. The presented methods offer several benefits, namely, high product yields and purity, simple operation, mild reaction conditions without use of hazardous organic solvents, while some of them could be implemented on industrial scale production.
A new ecologically friendly process for the synthesis of selective flotation reagents
Milutin M. Milosavljevi,Aleksandar D. Marinkovi?,Slobodan D. Petrovi?,Milica Sovrli?
Chemical Industry and Chemical Engineering Quarterly , 2009,
Abstract: A new ecologically friendly synthesis of N-alkyl-O-ethylthioncarbamates from ethyl dixanthogenates, waste material from the xanthate production plant, and monoalkylamines has been performed in this work. Structure determination of the synthesized compounds and also corresponding intermediates has been performed by IR, 1H-NMR and MS spectrometric methods. Residual dixanthogenates and thioncarbamates in waste water have been done by the gas chromatographic method and corresponding standard curve. It was confirmed that the reaction product was not present in water, while the concentration of dixanthogenates has been determined to be under the maximum contamination limit.
Synthesis of tetraalkyl thiuram disulfides using different oxidants in recycling solvent mixture
MilosavljeviMilutin M.,Marinkovi? Aleksandar D.,Markovi? Jelena M.,Brkovi? Danijela V.
Chemical Industry and Chemical Engineering Quarterly , 2012, DOI: 10.2298/ciceq110726048m
Abstract: A new optimized laboratory synthesis of tetraalkyl thiuram disulfides, starting from dialkyl amines and carbon disulfide in presence of three oxidants (hydrogen peroxide, potassium peroxodisulfate and sodium hypochlorite) and appropriate reaction medium: two mixtures of isopropyl alcohol - water used in two consecutive syntheses, was presented in this work. First synthesis was performed in a recycled azeotropic mixture of isopropyl alcohol - water 87.7% - 12.3%, and second in a filtrate obtained after first synthesis, which was a mixture of isopropyl alcohol - water 70.4% - 29.6%. After the second synthesis and filtration, recycled azeotropic mixture isopropyl alcohol - water 87.7% - 12.3% was regenerated from the filtrate by rectification. Considering this, the technology for beneficial use of recycling isopropyl alcohol - water mixture as reaction medium for tetraalkyl thiuram disulfides synthesis was developed. Such concept contributes to extraordinary economical benefit of implemented optimal laboratory synthesis at semi-industrial level. High yields of tetraalkyl thiuram disulfides syntheses were obtained at both laboratory and semiindustrial level. Structure and purity of synthesized compounds were confirmed by elemental analysis, as well as FTIR, 1H and 13C NMR, and MS spectral data.
On certain inequalities for some regular functions in |z|<1
Milutin Obradovi?
International Journal of Mathematics and Mathematical Sciences , 1985, DOI: 10.1155/s0161171285000746
Abstract: In this paper we give some inequalities for regular functions f(z)=z+a2z2+ ¢ € | in |z|<1 especially for starlike and convex functions of order ±, 0 ¢ ‰ ¤ ±<1, To some extent those inequalities are the generalisations and improvements of the previous results given by Bernardi [1]. Some interesting consequences are given, too.
Old values for new times: Svetislav Stefanovi , once and nowadays
Milosavljevi? Olivera
Sociologija , 2010, DOI: 10.2298/soc1004399m
Abstract: After the fall of communism and the collapse of Yugoslavia, the ” new” Serbian elite made a demarcation towards the former state in all aspects, including its interpretation of the past. This phenomenon is especially present in reevaluations of the fascist ideology of 1930s which is often relativized to the point of unrecognizability by adducing positive facts. A characteristic example discussed in this paper is the defense of Dr Svetislav Stefanovi ’s ideological principles by his contemporary biographers.
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