Chemistry Journal of Moldova

Physical chemistry and chemical physics

EFFECT OF THE NATURE OF SURFACTANT ON THE REACTIVITY OF C,N-DIPHENYLNITRONE TOWARDS ACRYLONITRILE IN DIFFERENT MICROEMULSION SYSTEMS

Author(s):

Kahina Hamza, Abdelkader Touati, Ahmed Ait-Yahia, Michel Baltas, Christiane André Barres, Saâd Moulay


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2018 Volume 13, no.2
Pages: 82-88
Keywords: acrylonitrile, cycloaddition, isoxazolidine, microemulsion, nitrone.
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DOI: http://dx.doi.org/10.19261/cjm.2018.522   

Abstract (PDF) 
Graphical Abstract: The present work provides an insight into the effect of the nature of surfactant (cationic, anionic), a component of water- and oil-borne microemulsions, on the reaction rate of 1,3-dipolar cycloaddition of C,N-diphenylnitrone with acrylonitrile. The electrostatically attractive character of the cationic surfactant, would bring the reactants closer to each other; hence, a rate enhancement would ensue, particularly within the water-rich zone. Besides the fact that acrylonitrile played a dual role, as a component of the microemulsion and a dipolarphile in the cycloaddition reaction, made the work-up advantageously sound. Additionally, the increase in reagents molar ratio was found to promote higher reactivity.


 

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MULTICOMPONENT CRYSTALLIZATION OF KETOPROFEN-NICOTINAMIDE FOR IMPROVING THE SOLUBILITY AND DISSOLUTION RATE

Author(s):

Yudi Wicaksono, Dwi Setyawan, Siswandono Siswandono


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2018 Volume 13, no.2
Pages: 74-81
Keywords: ketoprofen, multicomponent crystallization, solvent evaporation, solubility, dissolution rate.
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DOI: http://dx.doi.org/10.19261/cjm.2018.493   

Abstract (PDF) 
Graphical Abstract: The study was aimed at increasing solubility and dissolution rate of ketoprofen by using multicomponent crystallization approach with nicotinamide as additional material. The multicomponent crystallization was carried out by solvent evaporation method using 2-propanol as solvent. The solubility and dissolution test showed that the ketoprofen-nicotinamide multicomponent crystal has solubility and dissolution rate significantly higher than the solubility and dissolution rate of the pure ketoprofen.


 

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ADSORPTION OF STRONTIUM IONS FROM AQUEOUS SOLUTIONS ON NUT SHELLS ACTIVATED CARBONS

Author(s):

Gheorghe Duca, Mihai Ciobanu, Tudor Lupascu, Igor Povar


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2018 Volume 13, no.2
Pages: 69-73
Keywords: activated carbon, adsorption heat, entropy, exothermic process, strontium ion.
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DOI: http://dx.doi.org/10.19261/cjm.2018.494

Abstract (PDF)
Graphical Abstract: The adsorption of strontium ions from aqueous solutions on nut shells activated carbons (samples CAN-7 and CAN-8) at different temperatures has been studied. The isotherm of adsorption of strontium ions from aqueous solutions on activated carbon CAN-7 has two inflection points at relatively small and high equilibrium concentrations. As the temperature increases, the adsorption values decrease, which indicates that the adsorption process is exothermic.


 


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HYGROSCOPIC PROPERTIES OF ENOXIL-SILICA COMPOSITES

Author(s):

Oksana Stavinskaya, Iryna Laguta, Olga Kazakova, Pavlo Kuzema, Tudor Lupascu


Field: Physical chemistry and chemical physics
Type: Short communication
Issue: 2018 Volume 13, no.2
Pages: 89-92
Keywords: Enoxil, biomolecule, fumed silica, composite, hygroscopicity.
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DOI: http://dx.doi.org/10.19261/cjm.2018.487   

Abstract (PDF)
Graphical Abstract: Enoxil-silica composites with various Enoxil-to-silica ratios were prepared by mechanical mixing of the biologically active Enoxil and fumed silica powders. The hygroscopic properties of the composites were studied by the gravimetric method. . It was found that hygroscopicity is reduced by 30÷40% when the Enoxil-to-silica mass ratio in the composites is 0.15÷0.35.

 Holding time in desiccators: 92 (1), 141 (2) and 365 (3) days.

 

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THE POSSIBILITY OF Ce3+ AND Mn2+ COMPLEX IONS FORMATION WITH IODINE SPECIES IN A DUSHMAN REACTION

Author(s):

Iurie Ungureanu, Gheorghe Duca, Ionel Humelnicu, 
Gelu Bourceanu


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2018 Volume 13, no.1
Pages: 103-110
Keywords: Dushman reaction, cerium ion, manganese ion, iodine specie.
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DOI: http://dx.doi.org/10.19261/cjm.2017.464

Abstract (PDF) 
Graphical Abstract: This contribution presents investigations into possible effects of Ce3+ and Mn2+ on the reduction of UV-spectral signal for I3- observed e.g. in the Dushman reaction. The potential of the metal ions to form complexes with iodine-containing species was analysed. It was shown that no complex ions are formed between Ce3+ and Mn2+ metals ions with IO3-, I-, I2 species. Only the formation of a very weak CeI32+ complex ion was found to occur. An effect of a complex formation on the studied systems could be excluded.

 
 

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SILVER NANOPARTICLES SYNTHESIZED USING LANTANA CAMARA FLOWER EXTRACT BY REFLUX, MICROWAVE AND ULTRASOUND METHODS

Author(s):

Is Fatimah, Nurul Indriani


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2018 Volume 13, no.1
Pages: 95-102
Keywords: silver nanoparticle, green synthesis, Lantana camara, microwave, ultrasound.
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DOI:
http://dx.doi.org/10.19261/cjm.2017.461  

Abstract (PDF) 
Graphical Abstract: Green synthesis of silver nanoparticles (AgNPs) using Lantana camara yellow flower extract via microwave irradiation and ultrasound methods was conducted. The research was aimed at evaluating the effect of the synthesis method and also the time of treatment during synthesis on the particle size and antioxidant and antibacterial activities of the AgNPs. Analysis of the nanoparticles was performed using UV-Vis spectroscopy, transmission electron microscope (TEM), particle size analyzer, and Fourier transform infrared spectroscopy (FTIR). The present results support the advantages of plant extract and the green method for the production of nanoparticles for further potential applications.

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WATER BINDING THROUGH POLYACRYLAMIDE HYDROGEL AND THE INFLUENCE OF ITS PRELIMINARY SATURATION BY ENOXIL

Author(s):

Volodymyr Turov, Viktor Bogatyrev, Tatiana Krupska, Mariia Galaburda, Tudor Lupascu, Igor Povar, Natalia Kokosha


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2018 Volume 13, no.1
Pages: 87-94
Keywords: cluster, Enoxil, 1H NMR spectroscopy, polyacrylamide gel, polymer linkage.
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DOI:
http://dx.doi.org/10.19261/cjm.2017.459  

Abstract (PDF) 
Graphical Abstract: The state of water in a polyacrylamide (PPA) gel has been studied by the 1H NMR spectroscopy. It is shown that the PAA gel can serve as a container for prolonged retention of the Enoxil preparation without changing its chemical composition. At the same time, the molecular structures of Enoxil bind strongly to polymer chains, probably due to the formation of hydrogen-bound complexes with amino and imino groups.

1 - initial dry PAA, 2 - hydrogel PAA, 
3 - hydrogel PAA-Enoxil

Downloads: 33

NEW MESOPOROUS MATERIALS WITH SURFACE SUPRAMOLECULAR CENTRES FOR METHYL RED SORPTION

Author(s):

Nadiia Roik, Lyudmila Belyakova, Marina Dziazko, Iryna Trofymchuk


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 87-101
Keywords: mesoporous silica, β-cyclodextrin, chemical immobilization, methyl red, sorption
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DOI: http://dx.doi.org/10.19261/cjm.2017.419

Abstract (PDF)
Graphical Abstract: MCM-41-type silicas were obtained by template-assisted condensation of TEOS and β-CD-silanes. Removal of methyl red from phosphate buffer solutions as a function of pH and dye equilibrium concentration. Introduction of cyclic oligosaccharide in silica surface layer leads to the ecnhancement of sorption effieciency towards methyl red.




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SYNTHESIS OF SBA-15 TYPE ORGANOSILICA SORBENTS USING SODIUM METASILICATE AND PHOSPHONIC ACID RESIDUES

Author(s):

Oksana Dudarko *, Yuriy Zub


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 79-86
Keywords: SBA-15, phosphonic group, organosilica, characterization.
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DOI: http://dx.doi.org/10.19261/cjm.2017.417   
 
Abstract (PDF)
Graphical Abstract: The direct template method was used for the synthesis of mesoporous organosilica sorbents of SBA-15 type with phosphonic acid groups using sodium metasilicate (SS) as a source of silica. The presence of functional groups in the synthesized samples was confirmed by IR spectroscopy and elemental analysis. This approach allowed producing relatively cheap materials with ordered structure, developed specific surface (550-700 m2/g) and high sorption volume (0.74-0.81 cm3/g). The optimal sodium metasilicate (SS):diphosphoethyltriethoxysilane (DPTS) ratio for the synthesis of SBA-15 type organosilicas with phosphonic acid residues was found to be 10:2.


 

Downloads: 52

UNTANGLING THE INHIBITION EFFECTS OF ALIPHATIC AMINES ON SILVER CORROSION: A COMPUTATIONAL STUDY

Author(s):

Emre Topal, Gökhan Gece


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 64-70
Keywords: corrosion inhibitor, silver, aliphatic amines, density functional theory.
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DOI:
http://dx.doi.org/10.19261/cjm.2017.411
 
Abstract (PDF)
Supplementary Material (PDF)
Graphical Abstract: The topic of corrosion inhibition of different metals by organic compounds has been the focus of intense scrutiny for decades. The enormity of the problem is reflected in the need to understand the underlying inhibition mechanisms of such compounds, one of which is the class of aliphatic amines. Electrochemical measurements represent protective effect of these compounds at ever-increasing levels of detail but these methods lack the resolution to represent inhibition efficiency-molecular structure relations adequately. In this study, the dependence of the inhibition effect of four aliphatic amines (methylamine, ethylamine, n-propylamine, and n-butylamine), on their molecular and electronic structure is analyzed using quantum chemical calculations. The obtained results of these calculations were found to be consistent with the experimental findings.



 

Downloads: 46