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Veljković, Vlada B.

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orcid::0000-0002-1671-2892
  • Veljković, Vlada B. (14)
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Author's Bibliography

Valorization of walnut shell ash as a catalyst for biodiesel production

Miladinović, Marija R.; Zdujić, Miodrag; Veljović, Đorđe; Krstić, Jugoslav B.; Banković Ilić, Ivana B.; Veljković, Vlada B.; Stamenković, Olivera S.

(Elsevier, 2020)

TY  - JOUR
AU  - Miladinović, Marija R.
AU  - Zdujić, Miodrag
AU  - Veljović, Đorđe
AU  - Krstić, Jugoslav B.
AU  - Banković Ilić, Ivana B.
AU  - Veljković, Vlada B.
AU  - Stamenković, Olivera S.
PY  - 2020
UR  - http://dais.sanu.ac.rs/123456789/6903
AB  - The catalytic activity of the walnut shell ash was investigated in the biodiesel production by the sunflower oil methanolysis. The catalyst was characterized by the TG-DTA, XRD, Hg porosimetry, N2 physisorption, SEM, and Hammett method. In addition, the effects of the catalyst loading and the methanol-to-oil molar ratio on the methyl esters synthesis were tested at the reaction temperature of 60 °C. The walnut shell ash provided a very fast reaction and a high FAME content (over 98%). As the reaction occurred in the absence of triacylglycerols mass transfer limitation, the pseudo-first-order model was employed for describing the kinetics of the reaction. The catalyst was successfully reused four times after the regeneration of the catalytic activity by recalcination at 800 °C.
PB  - Elsevier
T2  - Renewable Energy
T1  - Valorization of walnut shell ash as a catalyst for biodiesel production
SP  - 1033
EP  - 1043
VL  - 147
DO  - 10.1016/j.renene.2019.09.056
ER  - 
@article{
author = "Miladinović, Marija R. and Zdujić, Miodrag and Veljović, Đorđe and Krstić, Jugoslav B. and Banković Ilić, Ivana B. and Veljković, Vlada B. and Stamenković, Olivera S.",
year = "2020",
url = "http://dais.sanu.ac.rs/123456789/6903",
abstract = "The catalytic activity of the walnut shell ash was investigated in the biodiesel production by the sunflower oil methanolysis. The catalyst was characterized by the TG-DTA, XRD, Hg porosimetry, N2 physisorption, SEM, and Hammett method. In addition, the effects of the catalyst loading and the methanol-to-oil molar ratio on the methyl esters synthesis were tested at the reaction temperature of 60 °C. The walnut shell ash provided a very fast reaction and a high FAME content (over 98%). As the reaction occurred in the absence of triacylglycerols mass transfer limitation, the pseudo-first-order model was employed for describing the kinetics of the reaction. The catalyst was successfully reused four times after the regeneration of the catalytic activity by recalcination at 800 °C.",
publisher = "Elsevier",
journal = "Renewable Energy",
title = "Valorization of walnut shell ash as a catalyst for biodiesel production",
pages = "1033-1043",
volume = "147",
doi = "10.1016/j.renene.2019.09.056"
}
11
6
12

Valorization of walnut shell ash as a catalyst for biodiesel production

Miladinović, Marija R.; Zdujić, Miodrag; Veljović, Đorđe; Krstić, Jugoslav B.; Banković Ilić, Ivana B.; Veljković, Vlada B.; Stamenković, Olivera S.

(Elsevier, 2020)

TY  - JOUR
AU  - Miladinović, Marija R.
AU  - Zdujić, Miodrag
AU  - Veljović, Đorđe
AU  - Krstić, Jugoslav B.
AU  - Banković Ilić, Ivana B.
AU  - Veljković, Vlada B.
AU  - Stamenković, Olivera S.
PY  - 2020
UR  - http://cer.ihtm.bg.ac.rs/handle/123456789/3217
UR  - http://dais.sanu.ac.rs/123456789/6717
AB  - The catalytic activity of the walnut shell ash was investigated in the biodiesel production by the sunflower oil methanolysis. The catalyst was characterized by the TG-DTA, XRD, Hg porosimetry, N2 physisorption, SEM, and Hammett method. In addition, the effects of the catalyst loading and the methanol-to-oil molar ratio on the methyl esters synthesis were tested at the reaction temperature of 60 °C. The walnut shell ash provided a very fast reaction and a high FAME content (over 98%). As the reaction occurred in the absence of triacylglycerols mass transfer limitation, the pseudo-first-order model was employed for describing the kinetics of the reaction. The catalyst was successfully reused four times after the regeneration of the catalytic activity by recalcination at 800 °C.
PB  - Elsevier
T2  - Renewable Energy
T1  - Valorization of walnut shell ash as a catalyst for biodiesel production
SP  - 1033
EP  - 1043
VL  - 147
DO  - 10.1016/j.renene.2019.09.056
ER  - 
@article{
author = "Miladinović, Marija R. and Zdujić, Miodrag and Veljović, Đorđe and Krstić, Jugoslav B. and Banković Ilić, Ivana B. and Veljković, Vlada B. and Stamenković, Olivera S.",
year = "2020",
url = "http://cer.ihtm.bg.ac.rs/handle/123456789/3217, http://dais.sanu.ac.rs/123456789/6717",
abstract = "The catalytic activity of the walnut shell ash was investigated in the biodiesel production by the sunflower oil methanolysis. The catalyst was characterized by the TG-DTA, XRD, Hg porosimetry, N2 physisorption, SEM, and Hammett method. In addition, the effects of the catalyst loading and the methanol-to-oil molar ratio on the methyl esters synthesis were tested at the reaction temperature of 60 °C. The walnut shell ash provided a very fast reaction and a high FAME content (over 98%). As the reaction occurred in the absence of triacylglycerols mass transfer limitation, the pseudo-first-order model was employed for describing the kinetics of the reaction. The catalyst was successfully reused four times after the regeneration of the catalytic activity by recalcination at 800 °C.",
publisher = "Elsevier",
journal = "Renewable Energy",
title = "Valorization of walnut shell ash as a catalyst for biodiesel production",
pages = "1033-1043",
volume = "147",
doi = "10.1016/j.renene.2019.09.056"
}
11
6
12

Supplementary data for the article: Todorović, Zoran B., Dragan Z. Troter, Dušica R. Đokić-Stojanović, Ana V. Veličković, Jelena M. Avramović, Olivera S. Stamenković, Ljiljana M. Veselinović, and Vlada B. Veljković. 2019. “Optimization of CaO-Catalyzed Sunflower Oil Methanolysis with Crude Biodiesel as a Cosolvent.” Fuel 237 (February): 903–10. https://doi.org/10.1016/j.fuel.2018.10.056

Todorović, Zoran B.; Troter, Dragan Z.; Đokić-Stojanović, Dušica R.; Veličković, Ana V.; Avramović, Jelena M.; Stamenković, Olivera S.; Veselinović, Ljiljana; Veljković, Vlada B.

(2019)

@misc{
author = "Todorović, Zoran B. and Troter, Dragan Z. and Đokić-Stojanović, Dušica R. and Veličković, Ana V. and Avramović, Jelena M. and Stamenković, Olivera S. and Veselinović, Ljiljana and Veljković, Vlada B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0016236118317691, http://dais.sanu.ac.rs/123456789/4071",
journal = "Fuel",
title = "Supplementary data for the article: Todorović, Zoran B., Dragan Z. Troter, Dušica R. Đokić-Stojanović, Ana V. Veličković, Jelena M. Avramović, Olivera S. Stamenković, Ljiljana M. Veselinović, and Vlada B. Veljković. 2019. “Optimization of CaO-Catalyzed Sunflower Oil Methanolysis with Crude Biodiesel as a Cosolvent.” Fuel 237 (February): 903–10. https://doi.org/10.1016/j.fuel.2018.10.056"
}

Supplementary material to Triethanolamine as an efficient cosolvent for biodiesel production by CaO-catalyzed sunflower oil ethanolysis: An optimization study

Đokić-Stojanović, Dušica R.; Todorović, Zoran B.; Troter, Dragan Z.; Stamenković, Olivera S.; Veselinović, Ljiljana; Zdujić, Miodrag; Manojlović, Dragan D.; Veljković, Vlada B.

(2019)

@misc{
author = "Đokić-Stojanović, Dušica R. and Todorović, Zoran B. and Troter, Dragan Z. and Stamenković, Olivera S. and Veselinović, Ljiljana and Zdujić, Miodrag and Manojlović, Dragan D. and Veljković, Vlada B.",
year = "2019",
url = "https://www.ache-pub.org.rs/index.php/HemInd/article/view/587/pdf_1, http://dais.sanu.ac.rs/123456789/7043",
abstract = "Figure D1. Normal probability plot of residuals (a), Cook's distances (b) and predicted and actual values of FAEE content (c); Table D1. Results of sequential model sum of squares test; Table D2. Results of lack of fit test; Table D3. Results of model summary statistics test",
journal = "Hemijska industrija",
title = "Supplementary material to Triethanolamine as an efficient cosolvent for biodiesel production by CaO-catalyzed sunflower oil ethanolysis: An optimization study",
pages = "D17-D18",
volume = "73",
number = "6"
}

Triethanolamine as an efficient cosolvent for biodiesel production by CaO-catalyzed sunflower oil ethanolysis: An optimization study

Đokić-Stojanović, Dušica R.; Todorović, Zoran B.; Troter, Dragan Z.; Stamenković, Olivera S.; Veselinović, Ljiljana; Zdujić, Miodrag; Manojlović, Dragan D.; Veljković, Vlada B.

(2019)

TY  - JOUR
AU  - Đokić-Stojanović, Dušica R.
AU  - Todorović, Zoran B.
AU  - Troter, Dragan Z.
AU  - Stamenković, Olivera S.
AU  - Veselinović, Ljiljana
AU  - Zdujić, Miodrag
AU  - Manojlović, Dragan D.
AU  - Veljković, Vlada B.
PY  - 2019
UR  - https://www.ache-pub.org.rs/index.php/HemInd/article/view/587
UR  - http://dais.sanu.ac.rs/123456789/7041
AB  - Triethanolamine was applied as an efficient „green“ cosolvent for biodiesel production by CaO-catalyzed ethanolysis of sunflower oil. The reaction was conducted in a batch stirred reactor and optimized with respect to the reaction temperature (61.6-78.4 °C), the ethanol-to-oil molar ratio (7:1-17:1) and the cosolvent loading (3-36 % of the oil weight) by using a rotatable central composite design (RCCD) combined with the response surface methodology (RSM). The optimal reaction conditions were found to be: the ethanol-to-oil molar ratio of 9:1, the reaction temperature of 75 °C and the cosolvent loading of 30 % to oil weight, which resulted in the predicted and actual fatty acid ethyl ester (FAEE) contents of 98.8 % and 97.9±1.3 %, respectively, achieved within only 20 min of the reaction. Also, high FAEE contents were obtained with expired sunflower oil, hempseed oil and waste lard. X-ray diffraction analysis (XRD) was used to understand the changes in the CaO phase. The CaO catalyst can be used without any treatment in two consecutive cycles. Due to the calcium leaching into the product, an additional purification stage must be included in the overall process.
T2  - Hemijska industrija
T1  - Triethanolamine as an efficient cosolvent for biodiesel production by CaO-catalyzed sunflower oil ethanolysis: An optimization study
SP  - 351
EP  - 362
VL  - 73
IS  - 6
DO  - 10.2298/HEMIND190822033D
ER  - 
@article{
author = "Đokić-Stojanović, Dušica R. and Todorović, Zoran B. and Troter, Dragan Z. and Stamenković, Olivera S. and Veselinović, Ljiljana and Zdujić, Miodrag and Manojlović, Dragan D. and Veljković, Vlada B.",
year = "2019",
url = "https://www.ache-pub.org.rs/index.php/HemInd/article/view/587, http://dais.sanu.ac.rs/123456789/7041",
abstract = "Triethanolamine was applied as an efficient „green“ cosolvent for biodiesel production by CaO-catalyzed ethanolysis of sunflower oil. The reaction was conducted in a batch stirred reactor and optimized with respect to the reaction temperature (61.6-78.4 °C), the ethanol-to-oil molar ratio (7:1-17:1) and the cosolvent loading (3-36 % of the oil weight) by using a rotatable central composite design (RCCD) combined with the response surface methodology (RSM). The optimal reaction conditions were found to be: the ethanol-to-oil molar ratio of 9:1, the reaction temperature of 75 °C and the cosolvent loading of 30 % to oil weight, which resulted in the predicted and actual fatty acid ethyl ester (FAEE) contents of 98.8 % and 97.9±1.3 %, respectively, achieved within only 20 min of the reaction. Also, high FAEE contents were obtained with expired sunflower oil, hempseed oil and waste lard. X-ray diffraction analysis (XRD) was used to understand the changes in the CaO phase. The CaO catalyst can be used without any treatment in two consecutive cycles. Due to the calcium leaching into the product, an additional purification stage must be included in the overall process.",
journal = "Hemijska industrija",
title = "Triethanolamine as an efficient cosolvent for biodiesel production by CaO-catalyzed sunflower oil ethanolysis: An optimization study",
pages = "351-362",
volume = "73",
number = "6",
doi = "10.2298/HEMIND190822033D"
}
1
1
1

Modeling the thermal and electrical conductivity relation of synthesized diamonds within fractal nature analysis

Mitić, Vojislav V.; Veljković, Vlada B.; Lazović, Goran; Mohr, Markus; Gluche, Peter; Paunović, Vesna; Fecht, Hans-Jörg

(Societa ceramica italiana, 2019)

TY  - CONF
AU  - Mitić, Vojislav V.
AU  - Veljković, Vlada B.
AU  - Lazović, Goran
AU  - Mohr, Markus
AU  - Gluche, Peter
AU  - Paunović, Vesna
AU  - Fecht, Hans-Jörg
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/7024
AB  - Improvement of novel materials could be very good development base for enhancement of new technologies. One of the most promising material of modern science is undoubtedly synthesized diamond. Because of variety of modern applications, the research in this area is becoming intensive. Utilization of this material made great step forward in many areas, beside the most known jewelry, also in producing microcomponents, in medical-surgery, as well as in high professional industry. These and others specific application of polycrystal diamonds, require permanently research and improvement of their properties. Although, the first synthesized diamond was created half a century ago using high pressure - high temperature (HPHT) method, diamonds created by chemical vapor deposition (CVD) method were much more convenient for application in so many areas. By applying CVD method, microcrystalline diamond (MCD) with grain size approximately 100 nm were created. Due to some disadvantages of MCD films, like values of hardness and Young’s modulus, new nanocrystalline (NCD) and ultra-nanocrystalline (UNCD) diamond materials were developed, with average grains size of 5-100 nm and 3-5 nm, respectively. The properties of polycrystalline diamonds can vary depending on the consolidation process like composition and pressure of applied gases, filament setup and reactor geometry. In that sense, changing the parameters of consolidation process, there is a possibility to change the microstructure of thin films and understanding its fundamentals. Also, fractal nature analysis could contribute to the revealing possibilities for improvement of polycrystalline diamond films. During carried out experiments, it was observed that there is the influence of grain size on thermal and electrical conductivity - when the thermal conductivity is increasing then electro conductivity is decreasing and opposite. Relation between the structures and final properties of synthetized diamonds can be achieved by explaining these phenomena based on fractal nature.
PB  - Societa ceramica italiana
PB  - Politecnico di Torino
C3  - Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019
T1  - Modeling the thermal and electrical conductivity relation of synthesized diamonds within fractal nature analysis
SP  - 672
EP  - 672
ER  - 
@conference{
author = "Mitić, Vojislav V. and Veljković, Vlada B. and Lazović, Goran and Mohr, Markus and Gluche, Peter and Paunović, Vesna and Fecht, Hans-Jörg",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/7024",
abstract = "Improvement of novel materials could be very good development base for enhancement of new technologies. One of the most promising material of modern science is undoubtedly synthesized diamond. Because of variety of modern applications, the research in this area is becoming intensive. Utilization of this material made great step forward in many areas, beside the most known jewelry, also in producing microcomponents, in medical-surgery, as well as in high professional industry. These and others specific application of polycrystal diamonds, require permanently research and improvement of their properties. Although, the first synthesized diamond was created half a century ago using high pressure - high temperature (HPHT) method, diamonds created by chemical vapor deposition (CVD) method were much more convenient for application in so many areas. By applying CVD method, microcrystalline diamond (MCD) with grain size approximately 100 nm were created. Due to some disadvantages of MCD films, like values of hardness and Young’s modulus, new nanocrystalline (NCD) and ultra-nanocrystalline (UNCD) diamond materials were developed, with average grains size of 5-100 nm and 3-5 nm, respectively. The properties of polycrystalline diamonds can vary depending on the consolidation process like composition and pressure of applied gases, filament setup and reactor geometry. In that sense, changing the parameters of consolidation process, there is a possibility to change the microstructure of thin films and understanding its fundamentals. Also, fractal nature analysis could contribute to the revealing possibilities for improvement of polycrystalline diamond films. During carried out experiments, it was observed that there is the influence of grain size on thermal and electrical conductivity - when the thermal conductivity is increasing then electro conductivity is decreasing and opposite. Relation between the structures and final properties of synthetized diamonds can be achieved by explaining these phenomena based on fractal nature.",
publisher = "Societa ceramica italiana, Politecnico di Torino",
journal = "Abstract Book / XVI Conference and Exhibition of the European Ceramic Society XVI ECerS Conference, Torino, 16-20 June 2019",
title = "Modeling the thermal and electrical conductivity relation of synthesized diamonds within fractal nature analysis",
pages = "672-672"
}

Influence of various cosolvents on the calcium oxide-catalyzed ethanolysis of sunflower oil

Đokić Stojanović, Dušica R.; Todorović, Zoran B.; Troter, Dragan; Stamenković, Olivera S.; Veselinović, Ljiljana; Zdujić, Miodrag; Manojlović, Dragan D.; Veljković, Vlada B.

(Belgrade : Serbian Chemical Society, 2019)

TY  - JOUR
AU  - Đokić Stojanović, Dušica R.
AU  - Todorović, Zoran B.
AU  - Troter, Dragan
AU  - Stamenković, Olivera S.
AU  - Veselinović, Ljiljana
AU  - Zdujić, Miodrag
AU  - Manojlović, Dragan D.
AU  - Veljković, Vlada B.
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6183
AB  - Ten organic solvents (triethanolamine, diethanolamine, ethylene glycol, methyl ethyl ketone, n-hexane, triethylamine, ethylene glycol dimethyl ether, glycerol, tetrahydrofuran and dioxane) were applied as cosolvents in the CaO-catalyzed ethanolysis of sunflower oil performed in a batch stirred reactor under the following reaction conditions: temperature 70 °C, ethanol-to-oil mole ratio 12:1, initial catalyst concentration 1.374 mol·L -1 and amount of cosolvent 20 % based on the oil amount. The main goals were to assess the effect of the used cosolvents on the synthesis of fatty acid ethyl esters (FAEE) and to select the most efficient one with respect to the final FAEE content, reaction duration and safety profile. In the absence of any cosolvent, the reaction was rather slow, providing a FAEE content of only 89.7±1.7 % after 4 h. Of the tested cosolvents, diethanolamine, triethanolamine and ethylene glycol significantly accelerated the ethanolysis reaction, whereby the last two provided a final FAEE content of 93.1±2.1 and 94.1±1.5 %, respectively, within 0.5 h. However, because of its safety profile, triethanolamine was selected as the best cosolvent for the ethanolysis of sunflower oil catalyzed by calcined CaO.
PB  - Belgrade : Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - Influence of various cosolvents on the calcium oxide-catalyzed ethanolysis of sunflower oil
SP  - 253
EP  - 265
VL  - 84
IS  - 3
DO  - 10.2298/JSC180827007D
ER  - 
@article{
author = "Đokić Stojanović, Dušica R. and Todorović, Zoran B. and Troter, Dragan and Stamenković, Olivera S. and Veselinović, Ljiljana and Zdujić, Miodrag and Manojlović, Dragan D. and Veljković, Vlada B.",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6183",
abstract = "Ten organic solvents (triethanolamine, diethanolamine, ethylene glycol, methyl ethyl ketone, n-hexane, triethylamine, ethylene glycol dimethyl ether, glycerol, tetrahydrofuran and dioxane) were applied as cosolvents in the CaO-catalyzed ethanolysis of sunflower oil performed in a batch stirred reactor under the following reaction conditions: temperature 70 °C, ethanol-to-oil mole ratio 12:1, initial catalyst concentration 1.374 mol·L -1 and amount of cosolvent 20 % based on the oil amount. The main goals were to assess the effect of the used cosolvents on the synthesis of fatty acid ethyl esters (FAEE) and to select the most efficient one with respect to the final FAEE content, reaction duration and safety profile. In the absence of any cosolvent, the reaction was rather slow, providing a FAEE content of only 89.7±1.7 % after 4 h. Of the tested cosolvents, diethanolamine, triethanolamine and ethylene glycol significantly accelerated the ethanolysis reaction, whereby the last two provided a final FAEE content of 93.1±2.1 and 94.1±1.5 %, respectively, within 0.5 h. However, because of its safety profile, triethanolamine was selected as the best cosolvent for the ethanolysis of sunflower oil catalyzed by calcined CaO.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "Influence of various cosolvents on the calcium oxide-catalyzed ethanolysis of sunflower oil",
pages = "253-265",
volume = "84",
number = "3",
doi = "10.2298/JSC180827007D"
}
1
1

Optimization of CaO-catalyzed sunflower oil methanolysis with crude biodiesel as a cosolvent

Todorović, Zoran B.; Troter, Dragan Z.; Đokić-Stojanović, Dušica R.; Veličković, Ana V.; Avramović, Jelena M.; Stamenković, Olivera S.; Veselinović, Ljiljana; Veljković, Vlada B.

(Elsevier, 2019)

TY  - JOUR
AU  - Todorović, Zoran B.
AU  - Troter, Dragan Z.
AU  - Đokić-Stojanović, Dušica R.
AU  - Veličković, Ana V.
AU  - Avramović, Jelena M.
AU  - Stamenković, Olivera S.
AU  - Veselinović, Ljiljana
AU  - Veljković, Vlada B.
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0016236118317691
UR  - http://dais.sanu.ac.rs/123456789/4070
AB  - Crude biodiesel was proven as a cosolvent in the methanolysis of sunflower oil catalyzed by calcined CaO. This reaction was modeled and optimized statistically in terms of reaction temperature (33.2–66.8 °C), methanol-to-oil molar ratio (3.5:1–8.5:1) and catalyst concentration (0.219–1.065 mol/L). The cosolvent loading was 10 wt% (based on oil weight). The optimum reaction conditions were found to be: the methanol-to-oil molar ratio of 7.1:1, the catalyst concentration of 0.74 mol/L and the reaction temperature 52 °C, ensuring the best esters content of 99.8%, for the reaction time of 1.5 h, which is close to the reported experimental value of 98.9%. Also, the used catalyst was recycled with no additional treatment in the further four consecutive cycles under the following reaction conditions: methanol-to-oil molar ratio 6:1, the concentration of catalyst 0.642 mol/L (only in the first run), the reaction temperature 50 °C, cosolvent-crude biodiesel loading 10 wt% to oil weight. The second recycling reaction provided the highest FAME content of 97.7% after 5 h.
PB  - Elsevier
T2  - Fuel
T1  - Optimization of CaO-catalyzed sunflower oil methanolysis with crude biodiesel as a cosolvent
SP  - 903
EP  - 910
VL  - 237
DO  - 10.1016/j.fuel.2018.10.056
ER  - 
@article{
author = "Todorović, Zoran B. and Troter, Dragan Z. and Đokić-Stojanović, Dušica R. and Veličković, Ana V. and Avramović, Jelena M. and Stamenković, Olivera S. and Veselinović, Ljiljana and Veljković, Vlada B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0016236118317691, http://dais.sanu.ac.rs/123456789/4070",
abstract = "Crude biodiesel was proven as a cosolvent in the methanolysis of sunflower oil catalyzed by calcined CaO. This reaction was modeled and optimized statistically in terms of reaction temperature (33.2–66.8 °C), methanol-to-oil molar ratio (3.5:1–8.5:1) and catalyst concentration (0.219–1.065 mol/L). The cosolvent loading was 10 wt% (based on oil weight). The optimum reaction conditions were found to be: the methanol-to-oil molar ratio of 7.1:1, the catalyst concentration of 0.74 mol/L and the reaction temperature 52 °C, ensuring the best esters content of 99.8%, for the reaction time of 1.5 h, which is close to the reported experimental value of 98.9%. Also, the used catalyst was recycled with no additional treatment in the further four consecutive cycles under the following reaction conditions: methanol-to-oil molar ratio 6:1, the concentration of catalyst 0.642 mol/L (only in the first run), the reaction temperature 50 °C, cosolvent-crude biodiesel loading 10 wt% to oil weight. The second recycling reaction provided the highest FAME content of 97.7% after 5 h.",
publisher = "Elsevier",
journal = "Fuel",
title = "Optimization of CaO-catalyzed sunflower oil methanolysis with crude biodiesel as a cosolvent",
pages = "903-910",
volume = "237",
doi = "10.1016/j.fuel.2018.10.056"
}
15
12
14

Optimization of CaO-catalyzed sunflower oil methanolysis with crude biodiesel as a cosolvent

Todorović, Zoran B.; Troter, Dragan Z.; Đokić Stojanović, Dušica R.; Veličković, Ana V.; Avramović, Jelena M.; Stamenković, Olivera S.; Veselinović, Ljiljana; Veljković, Vlada B.

(Elsevier, 2019)

TY  - JOUR
AU  - Todorović, Zoran B.
AU  - Troter, Dragan Z.
AU  - Đokić Stojanović, Dušica R.
AU  - Veličković, Ana V.
AU  - Avramović, Jelena M.
AU  - Stamenković, Olivera S.
AU  - Veselinović, Ljiljana
AU  - Veljković, Vlada B.
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0016236118317691
UR  - http://dais.sanu.ac.rs/123456789/4069
AB  - Crude biodiesel was proven as a cosolvent in the methanolysis of sunflower oil catalyzed by calcined CaO. This reaction was modeled and optimized statistically in terms of reaction temperature (33.2–66.8 °C), methanol-to-oil molar ratio (3.5:1–8.5:1) and catalyst concentration (0.219–1.065 mol/L). The cosolvent loading was 10 wt% (based on oil weight). The optimum reaction conditions were found to be: the methanol-to-oil molar ratio of 7.1:1, the catalyst concentration of 0.74 mol/L and the reaction temperature 52 °C, ensuring the best esters content of 99.8%, for the reaction time of 1.5 h, which is close to the reported experimental value of 98.9%. Also, the used catalyst was recycled with no additional treatment in the further four consecutive cycles under the following reaction conditions: methanol-to-oil molar ratio 6:1, the concentration of catalyst 0.642 mol/L (only in the first run), the reaction temperature 50 °C, cosolvent-crude biodiesel loading 10 wt% to oil weight. The second recycling reaction provided the highest FAME content of 97.7% after 5 h.
PB  - Elsevier
T2  - Fuel
T1  - Optimization of CaO-catalyzed sunflower oil methanolysis with crude biodiesel as a cosolvent
SP  - 903
EP  - 910
VL  - 237
DO  - 10.1016/j.fuel.2018.10.056
ER  - 
@article{
author = "Todorović, Zoran B. and Troter, Dragan Z. and Đokić Stojanović, Dušica R. and Veličković, Ana V. and Avramović, Jelena M. and Stamenković, Olivera S. and Veselinović, Ljiljana and Veljković, Vlada B.",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0016236118317691, http://dais.sanu.ac.rs/123456789/4069",
abstract = "Crude biodiesel was proven as a cosolvent in the methanolysis of sunflower oil catalyzed by calcined CaO. This reaction was modeled and optimized statistically in terms of reaction temperature (33.2–66.8 °C), methanol-to-oil molar ratio (3.5:1–8.5:1) and catalyst concentration (0.219–1.065 mol/L). The cosolvent loading was 10 wt% (based on oil weight). The optimum reaction conditions were found to be: the methanol-to-oil molar ratio of 7.1:1, the catalyst concentration of 0.74 mol/L and the reaction temperature 52 °C, ensuring the best esters content of 99.8%, for the reaction time of 1.5 h, which is close to the reported experimental value of 98.9%. Also, the used catalyst was recycled with no additional treatment in the further four consecutive cycles under the following reaction conditions: methanol-to-oil molar ratio 6:1, the concentration of catalyst 0.642 mol/L (only in the first run), the reaction temperature 50 °C, cosolvent-crude biodiesel loading 10 wt% to oil weight. The second recycling reaction provided the highest FAME content of 97.7% after 5 h.",
publisher = "Elsevier",
journal = "Fuel",
title = "Optimization of CaO-catalyzed sunflower oil methanolysis with crude biodiesel as a cosolvent",
pages = "903-910",
volume = "237",
doi = "10.1016/j.fuel.2018.10.056"
}
15
12
14

Supplementary material for the article: Troter, D.Z., Todorović, Z.B., Đokić-Stojanović, D.R., Veselinović, L.M., Zdujić, M.V., Veljković, V.B., 2018. Choline chloride-based deep eutectic solvents in CaO-catalyzed ethanolysis of expired sunflower oil. Journal of Molecular Liquids 266, 557–567. https://doi.org/10.1016/j.molliq.2018.06.106

Troter, Dragan Z.; Todorović, Zoran B.; Đokić Stojanović, Dušica R.; Veselinović, Ljiljana; Zdujić, Miodrag; Veljković, Vlada B.

(2018)

@misc{
author = "Troter, Dragan Z. and Todorović, Zoran B. and Đokić Stojanović, Dušica R. and Veselinović, Ljiljana and Zdujić, Miodrag and Veljković, Vlada B.",
year = "2018",
url = "http://dais.sanu.ac.rs/123456789/3772",
journal = "Journal of Molecular Liquids",
title = "Supplementary material for the article: Troter, D.Z., Todorović, Z.B., Đokić-Stojanović, D.R., Veselinović, L.M., Zdujić, M.V., Veljković, V.B., 2018. Choline chloride-based deep eutectic solvents in CaO-catalyzed ethanolysis of expired sunflower oil. Journal of Molecular Liquids 266, 557–567. https://doi.org/10.1016/j.molliq.2018.06.106",
volume = "266"
}

Choline chloride-based deep eutectic solvents in CaO-catalyzed ethanolysis of expired sunflower oil

Troter, Dragan Z.; Todorović, Zoran B.; Đokić Stojanović, Dušica R.; Veselinović, Ljiljana; Zdujić, Miodrag; Veljković, Vlada B.

(Elsevier, 2018)

TY  - JOUR
AU  - Troter, Dragan Z.
AU  - Todorović, Zoran B.
AU  - Đokić Stojanović, Dušica R.
AU  - Veselinović, Ljiljana
AU  - Zdujić, Miodrag
AU  - Veljković, Vlada B.
PY  - 2018
UR  - http://dais.sanu.ac.rs/123456789/3694
AB  - Choline chloride (ChCl)-based deep eutectic solvents (DESs) with different amides or polyols as hydrogen bond donors were tested as cosolvents in the ethanolysis of expired sunflower oil catalyzed by either calcined or non-calcined CaO. These cosolvents promoted the ethanolysis by a successful activation of non-calcined CaO, which was ascribed to the CaCO3 and Ca(OH)2 dissolution from the surface of the solid catalyst particles. With both calcined and non-calcined CaO, the polyol-based solvents gave higher fatty acid ethyl esters (FAEE) content than the amide-based solvents. Among the amide-based DESs, choline chloride:urea (ChCl:U) was the most efficient activator of non-calcined CaO. Choline chloride:ethylene glycol (ChCl:EG) and choline chloride:propylene glycol (ChCl:PG) were more efficient than choline chloride:glycerol (ChCl:G) even with non-calcined CaO. However, ChCl:G might be more suitable than the others since the use of glycerol, a by-product of the ethanolysis, could reduce the overall biodiesel production costs. FTIR and XRD analyses of the used and separated CaO were performed in order to get more insight into the catalytically active phase(s). Also, the mechanisms of the CaO activation in the presence of the DESs were considered. The phase separation of the reaction mixture was faster in the presence of the DESs. Since ChCl:U and ChCl:G DESs are nontoxic, biodegradable, biorenewable and “green” solvents and provide the elimination of the calcination step of CaO, thus reducing the overall process costs, the non-calcined CaO catalytic systems with these DESs are recommended for further optimization. © 2018 Elsevier B.V.
PB  - Elsevier
T2  - Journal of Molecular Liquids
T1  - Choline chloride-based deep eutectic solvents in CaO-catalyzed ethanolysis of expired sunflower oil
SP  - 557
EP  - 567
VL  - 266
DO  - 10.1016/j.molliq.2018.06.106
ER  - 
@article{
author = "Troter, Dragan Z. and Todorović, Zoran B. and Đokić Stojanović, Dušica R. and Veselinović, Ljiljana and Zdujić, Miodrag and Veljković, Vlada B.",
year = "2018",
url = "http://dais.sanu.ac.rs/123456789/3694",
abstract = "Choline chloride (ChCl)-based deep eutectic solvents (DESs) with different amides or polyols as hydrogen bond donors were tested as cosolvents in the ethanolysis of expired sunflower oil catalyzed by either calcined or non-calcined CaO. These cosolvents promoted the ethanolysis by a successful activation of non-calcined CaO, which was ascribed to the CaCO3 and Ca(OH)2 dissolution from the surface of the solid catalyst particles. With both calcined and non-calcined CaO, the polyol-based solvents gave higher fatty acid ethyl esters (FAEE) content than the amide-based solvents. Among the amide-based DESs, choline chloride:urea (ChCl:U) was the most efficient activator of non-calcined CaO. Choline chloride:ethylene glycol (ChCl:EG) and choline chloride:propylene glycol (ChCl:PG) were more efficient than choline chloride:glycerol (ChCl:G) even with non-calcined CaO. However, ChCl:G might be more suitable than the others since the use of glycerol, a by-product of the ethanolysis, could reduce the overall biodiesel production costs. FTIR and XRD analyses of the used and separated CaO were performed in order to get more insight into the catalytically active phase(s). Also, the mechanisms of the CaO activation in the presence of the DESs were considered. The phase separation of the reaction mixture was faster in the presence of the DESs. Since ChCl:U and ChCl:G DESs are nontoxic, biodegradable, biorenewable and “green” solvents and provide the elimination of the calcination step of CaO, thus reducing the overall process costs, the non-calcined CaO catalytic systems with these DESs are recommended for further optimization. © 2018 Elsevier B.V.",
publisher = "Elsevier",
journal = "Journal of Molecular Liquids",
title = "Choline chloride-based deep eutectic solvents in CaO-catalyzed ethanolysis of expired sunflower oil",
pages = "557-567",
volume = "266",
doi = "10.1016/j.molliq.2018.06.106"
}
7
6
6

Continuous biodiesel production under subcritical condition of methanol – Design of pilot plant and packed bed reactor with MnCO3/Na-silicate catalyst

Liu, Hui; Lukić, Ivana; Miladinović, Marija R.; Veljković, Vlada B.; Zdujić, Miodrag; Zhu, Xiaosun; Zhang, Yanan; Skala, Dejan

(Elsevier, 2018)

TY  - JOUR
AU  - Liu, Hui
AU  - Lukić, Ivana
AU  - Miladinović, Marija R.
AU  - Veljković, Vlada B.
AU  - Zdujić, Miodrag
AU  - Zhu, Xiaosun
AU  - Zhang, Yanan
AU  - Skala, Dejan
PY  - 2018
UR  - http://dais.sanu.ac.rs/123456789/3701
AB  - The continuous biodiesel production from soybean oil was carried out under the subcritical condition of methanol with MnCO3/Na-silicate as a heterogeneous catalyst. The transesterification rate was first investigated in a set of experiments performed in a batch autoclave at 448 K using methanol-to-oil molar ratio of 18:1 and various catalyst loadings (5, 10 and 20 wt% based on the oil mass). The results from these experiments, as well as the experimental data and the appropriate kinetic model recently reported in the literature were used for designing a packed bed tubular reactor (PBTR), a main unit of the pilot plant with the capacity of 100 L of biodiesel per day. The pilot plant was constructed and tested under various operating conditions. The first 11 h of the pilot-plant operation was realized in the tubular reactor packed with inert glass beads (i.e. without the catalyst) in order to analyze the effect of the non-catalyzed subcritical biodiesel (fatty acid methyl esters, FAME) production. Then, glass beads were replaced with a mix of MnCO3/Na-silicate catalyst particles and glass beads, and the catalytic biodiesel production was continuously run under the subcritical methanol condition for 85 h. Two mass balance tests during the continuous pilot plant operation were performed. © 2018 Elsevier Ltd
PB  - Elsevier
T2  - Energy Conversion and Management
T1  - Continuous biodiesel production under subcritical condition of methanol – Design of pilot plant and packed bed reactor with MnCO3/Na-silicate catalyst
SP  - 494
EP  - 504
VL  - 168
DO  - 10.1016/j.enconman.2018.05.028
ER  - 
@article{
author = "Liu, Hui and Lukić, Ivana and Miladinović, Marija R. and Veljković, Vlada B. and Zdujić, Miodrag and Zhu, Xiaosun and Zhang, Yanan and Skala, Dejan",
year = "2018",
url = "http://dais.sanu.ac.rs/123456789/3701",
abstract = "The continuous biodiesel production from soybean oil was carried out under the subcritical condition of methanol with MnCO3/Na-silicate as a heterogeneous catalyst. The transesterification rate was first investigated in a set of experiments performed in a batch autoclave at 448 K using methanol-to-oil molar ratio of 18:1 and various catalyst loadings (5, 10 and 20 wt% based on the oil mass). The results from these experiments, as well as the experimental data and the appropriate kinetic model recently reported in the literature were used for designing a packed bed tubular reactor (PBTR), a main unit of the pilot plant with the capacity of 100 L of biodiesel per day. The pilot plant was constructed and tested under various operating conditions. The first 11 h of the pilot-plant operation was realized in the tubular reactor packed with inert glass beads (i.e. without the catalyst) in order to analyze the effect of the non-catalyzed subcritical biodiesel (fatty acid methyl esters, FAME) production. Then, glass beads were replaced with a mix of MnCO3/Na-silicate catalyst particles and glass beads, and the catalytic biodiesel production was continuously run under the subcritical methanol condition for 85 h. Two mass balance tests during the continuous pilot plant operation were performed. © 2018 Elsevier Ltd",
publisher = "Elsevier",
journal = "Energy Conversion and Management",
title = "Continuous biodiesel production under subcritical condition of methanol – Design of pilot plant and packed bed reactor with MnCO3/Na-silicate catalyst",
pages = "494-504",
volume = "168",
doi = "10.1016/j.enconman.2018.05.028"
}
2
2
2

Choline chloride-based deep eutectic solvents in CaO-catalyzed ethanolysis of expired sunflower oil

Troter, Dragan Z.; Todorović, Zoran B.; Stojanović, Đokić; Đokić Stojanović, Dušica R.; Veselinović, Ljiljana; Zdujić, Miodrag; Veljković, Vlada B.

(2018)

TY  - JOUR
AU  - Troter, Dragan Z.
AU  - Todorović, Zoran B.
AU  - Stojanović, Đokić
AU  - Đokić Stojanović, Dušica R.
AU  - Veselinović, Ljiljana
AU  - Zdujić, Miodrag
AU  - Veljković, Vlada B.
PY  - 2018
UR  - http://dais.sanu.ac.rs/123456789/3802
AB  - Choline chloride (ChCl)-based deep eutectic solvents (DESs) with different amides or polyols as hydrogen bond donors were tested as cosolvents in the ethanolysis of expired sunflower oil catalyzed by either calcined or non-calcined CaO. These cosolvents promoted the ethanolysis by a successful activation of non-calcined CaO, which was ascribed to the CaCO3 and Ca(OH)2 dissolution from the surface of the solid catalyst particles. With both calcined and non-calcined CaO, the polyol-based solvents gave higher fatty acid ethyl esters (FAEE) content than the amide-based solvents. Among the amide-based DESs, choline chloride:urea (ChCl:U) was the most efficient activator of non-calcined CaO. Choline chloride:ethylene glycol (ChCl:EG) and choline chloride:propylene glycol (ChCl:PG) were more efficient than choline chloride:glycerol (ChCl:G) even with non-calcined CaO. However, ChCl:G might be more suitable than the others since the use of glycerol, a by-product of the ethanolysis, could reduce the overall biodiesel production costs. FTIR and XRD analyses of the used and separated CaO were performed in order to get more insight into the catalytically active phase(s). Also, the mechanisms of the CaO activation in the presence of the DESs were considered. The phase separation of the reaction mixture was faster in the presence of the DESs. Since ChCl:U and ChCl:G DESs are nontoxic, biodegradable, biorenewable and “green” solvents and provide the elimination of the calcination step of CaO, thus reducing the overall process costs, the non-calcined CaO catalytic systems with these DESs are recommended for further optimization. © 2018 Elsevier B.V.
T2  - Journal of Molecular Liquids
T1  - Choline chloride-based deep eutectic solvents in CaO-catalyzed ethanolysis of expired sunflower oil
SP  - 557
EP  - 567
VL  - 266
DO  - 10.1016/j.molliq.2018.06.106
ER  - 
@article{
author = "Troter, Dragan Z. and Todorović, Zoran B. and Stojanović, Đokić and Đokić Stojanović, Dušica R. and Veselinović, Ljiljana and Zdujić, Miodrag and Veljković, Vlada B.",
year = "2018",
url = "http://dais.sanu.ac.rs/123456789/3802",
abstract = "Choline chloride (ChCl)-based deep eutectic solvents (DESs) with different amides or polyols as hydrogen bond donors were tested as cosolvents in the ethanolysis of expired sunflower oil catalyzed by either calcined or non-calcined CaO. These cosolvents promoted the ethanolysis by a successful activation of non-calcined CaO, which was ascribed to the CaCO3 and Ca(OH)2 dissolution from the surface of the solid catalyst particles. With both calcined and non-calcined CaO, the polyol-based solvents gave higher fatty acid ethyl esters (FAEE) content than the amide-based solvents. Among the amide-based DESs, choline chloride:urea (ChCl:U) was the most efficient activator of non-calcined CaO. Choline chloride:ethylene glycol (ChCl:EG) and choline chloride:propylene glycol (ChCl:PG) were more efficient than choline chloride:glycerol (ChCl:G) even with non-calcined CaO. However, ChCl:G might be more suitable than the others since the use of glycerol, a by-product of the ethanolysis, could reduce the overall biodiesel production costs. FTIR and XRD analyses of the used and separated CaO were performed in order to get more insight into the catalytically active phase(s). Also, the mechanisms of the CaO activation in the presence of the DESs were considered. The phase separation of the reaction mixture was faster in the presence of the DESs. Since ChCl:U and ChCl:G DESs are nontoxic, biodegradable, biorenewable and “green” solvents and provide the elimination of the calcination step of CaO, thus reducing the overall process costs, the non-calcined CaO catalytic systems with these DESs are recommended for further optimization. © 2018 Elsevier B.V.",
journal = "Journal of Molecular Liquids",
title = "Choline chloride-based deep eutectic solvents in CaO-catalyzed ethanolysis of expired sunflower oil",
pages = "557-567",
volume = "266",
doi = "10.1016/j.molliq.2018.06.106"
}
7
6
6

Assessment of CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 perovskites as heterogeneous base catalysts for biodiesel synthesis

Kesić, Željka; Lukić, Ivana; Zdujić, Miodrag; Jovalekić, Čedomir; Veljković, Vlada B.; Skala, Dejan

(Elsevier, 2016)

TY  - JOUR
AU  - Kesić, Željka
AU  - Lukić, Ivana
AU  - Zdujić, Miodrag
AU  - Jovalekić, Čedomir
AU  - Veljković, Vlada B.
AU  - Skala, Dejan
PY  - 2016
UR  - http://dais.sanu.ac.rs/123456789/2363
AB  - Calcium-containing perovskites CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 were synthesized by calcination of mechanochemically treated stoichiometric mixtures of CaCO3 and either TiO2, MnO2, ZrO2 or Fe2O3 powders. X-ray diffraction analysis revealed a pure single perovskite phase for all four samples after calcination. This study proved that the pure perovskite phase exhibited low or no catalytic activity at 60 °C for the methanolysis of sunflower oil. However, at 165 °C FAME yield of more than 90% was reached after 2 h using CaTiO3, CaMnO3 and CaZrO3 as catalyst. Contrary to inactive pure perovskites at 60 °C, the CaTiO3 and Ca2Fe2O5 samples containing a very small amount of “free” CaO also showed methanolysis activity at 60 °C. This fact can be used to explain some contradictory statements reported in literature related to the perovskites as catalyst for biodiesel synthesis at mild temperatures.
PB  - Elsevier
T2  - Fuel Processing Technology
T1  - Assessment of CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 perovskites as heterogeneous base catalysts for biodiesel synthesis
SP  - 162
EP  - 168
VL  - 143
DO  - 10.1016/j.fuproc.2015.11.018
ER  - 
@article{
author = "Kesić, Željka and Lukić, Ivana and Zdujić, Miodrag and Jovalekić, Čedomir and Veljković, Vlada B. and Skala, Dejan",
year = "2016",
url = "http://dais.sanu.ac.rs/123456789/2363",
abstract = "Calcium-containing perovskites CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 were synthesized by calcination of mechanochemically treated stoichiometric mixtures of CaCO3 and either TiO2, MnO2, ZrO2 or Fe2O3 powders. X-ray diffraction analysis revealed a pure single perovskite phase for all four samples after calcination. This study proved that the pure perovskite phase exhibited low or no catalytic activity at 60 °C for the methanolysis of sunflower oil. However, at 165 °C FAME yield of more than 90% was reached after 2 h using CaTiO3, CaMnO3 and CaZrO3 as catalyst. Contrary to inactive pure perovskites at 60 °C, the CaTiO3 and Ca2Fe2O5 samples containing a very small amount of “free” CaO also showed methanolysis activity at 60 °C. This fact can be used to explain some contradictory statements reported in literature related to the perovskites as catalyst for biodiesel synthesis at mild temperatures.",
publisher = "Elsevier",
journal = "Fuel Processing Technology",
title = "Assessment of CaTiO3, CaMnO3, CaZrO3 and Ca2Fe2O5 perovskites as heterogeneous base catalysts for biodiesel synthesis",
pages = "162-168",
volume = "143",
doi = "10.1016/j.fuproc.2015.11.018"
}
26
26
30