Chemistry Journal of Moldova

2017 Volume 12, no.2

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.


 

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SYNTHESIS, OPTIMIZATION, CHARACTERIZATION AND ANTIMICROBIAL STUDIES OF Cu(II) AND Co(III) COMPLEXES OF BIS(2,2/-METHYLYLIDENEPHENOL)DIAMINOETHANE

Author(s):

Felix Sunday Nworie, Frank Ikenna Nwabue


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 41-49
Keywords: H2BMPDE-complex, modelling, physicochemical study, antimicrobial bio-efficiency.
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DOI: http://dx.doi.org/10.19261/cjm.2017.392   
 
Abstract (PDF)
Graphical Abstract: A new synthetic extractive protocol for the synthesis of Cu(II) and Co(III) complexes of bis(2,2/-methylylidenephenol)diaminoethane (H2BMPDE) in a single simple step was performed. The obtained data indicated the formation of complexes with 1:1 molar ratio of metal:ligand, of distorted square planar and distorted octahedral geometries. In vitro antibacterial screening revealed that the complexes were active against clinically important gram-negative bacteria (Escherichia coli, pseudomonas, and gram-positive bacterium (Staphylococcus aureus). The synthesis of the complexes was optimized to make it more suitable and efficient for industrial scale production.


 
 

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MORPHOLOGICAL AND THERMOANALYTICAL STUDY OF MODIFIED AVOCADO SEEDS STARCH WITH LACTIC ACID

Author(s):

Camila Delinski Bet, Lucas Henrique Waiga, Cristina Soltovski de Oliveira, Luiz Gustavo Lacerda, Egon Schnitzler


Field: Food chemistry
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 13-18
Keywords: avocado starch, lactic acid, modification, thermal analysis.
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DOI: http://dx.doi.org/10.19261/cjm.2017.438   
 
Abstract (PDF)
Graphical Abstract: Avocado seeds starch was investigated after the modification with lactic acid using thermogravimetry and differential thermal analysis, differential scanning calorimetry, X-ray powder diffraction and scanning electron microscopy. After the modification, there was a decrease in the thermal stability of the starch, also the parameters measured by differential scanning calorimetry showed lower values. There was no difference in the morphology of the granules, which presented an oval and rounded shape. 



 

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TRINUCLEAR MIXED-VALENT MANGANESE COMPLEX WITH NON-SCHIFF-BASE TETRADENTATE LIGAND SHOWING A FERROMAGNETIC COUPLING

Author(s):

Masahiro Mikuriya, Iyo Matsushima, Daisuke Yoshioka


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 34-40
Keywords: manganese complex, trinuclear complex, magnetic property, ferromagnetic interaction, mixed-valent complex.
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DOI: http://dx.doi.org/10.19261/cjm.2017.446   
 
Abstract (PDF)
Graphical Abstract: Mixed-valent trinuclear manganese complex with N,N’-bis(2-hydroxy-3,5-dimethylbenzyl-N,N’-dimethyl-1,2-ethanediamine (H2hdde), [Mn3(hdde)2(CH3CO2)2(CH3O)2], was synthesized.  The X-ray crystal structure analysis revealed a linearly arrangement of MnIII-MnII-MnIIIcore, where a ferromagnetic coupling (J = 2.62 cm–1) between the MnIII and MnII ions.


 

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SYNTHESIS AND CRYSTAL STRUCTURES OF LUMINESCENT MONONUCLEAR Ni(II) AND Cd(II) COMPLEXES WITH 1,10-PHENANTHROLINE

Author(s):

Ecaterina Tocana, Anatolii Siminel, Lilia Croitor


Field: Supramolecular chemistry
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 102-108
Keywords: X-ray, 1,10-phenanthroline, supramolecular system, π–π stacking interaction, luminescence.
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DOI: http://dx.doi.org/10.19261/cjm.2017.451   
 
Abstract (PDF)
Graphical Abstract: New supramolecular systems of Ni(II) and Cd(II) with 1,10-phenanthroline constructed by non-covalent interactions have been synthesized and characterized by single-crystal X-ray diffractometry. The smaller nickel(II) ion forms a cis complex with outer-sphere perchlorates, while the cadmium(II) ion forms a trans complex involving inner-sphere perchlorates. Both compoundsrevealintraligand-basedluminescentproperties.


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ADSORPTION OF CADMIUM IONS FROM WATER ON DOUBLE-WALLED CARBON NANOTUBES/IRON OXIDE COMPOSITE

Author(s):

Karima Seffah, Amel Zafour-Hadj-Ziane, Abdelghani Tarek Achour, Jean-François Guillet, Pierre Lonchambon, Emmanuel Flahaut


Field: Ecological chemistry
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 71-78
Keywords: double-walled carbon nanotubes, iron oxide, adsorption, cadmium ions.
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DOI: http://dx.doi.org/10.19261/cjm.2017.412   

Abstract (PDF)
Graphical Abstract: A new material (DWCNT/iron oxide) for heavy metals removal was developed by combining the adsorption features of double-walled carbon nanotubes with the magnetic properties of iron oxides. Batch experiments were applied in order to evaluate adsorption capacity of the DWCNT/iron oxide composite for cadmium ions. The influence of operating parameters such as pH value, amount of adsorbent, initial adsorbate concentration and agitation speed was studied. The adsorption capacity of the DWCNT/iron oxide adsorbent for Cd2+ ions was 20.8 mg g-1, which is at the state of the art. The obtained results revealed that DWCNT/iron oxide composite is a very promising adsorbent for removal of Cd2+ ions from water under natural conditions. The advantage of the magnetic composite is that it can be used as adsorbent for contaminants in water and can be subsequently controlled and removed from the medium by a simple magnetic process.


 

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THIONATION OF ESSENTIAL OILS FROM ALGERIAN ARTEMISIA HERBA-ALBA L. AND RUTA MONTANA L.: IMPACT ON THEIR ANTIMICROBIAL AND INSECTICIDAL ACTIVITIES

Author(s):

Nassiba Fekhar, Hocine Boutoumi, Mohamed Krea, Saâd Moulay, Drioueche Asma, Zoubir Benmaamar


Field: Natural product chemistry and synthesis
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 50-57
Keywords: essential oil, thionation, Artemisia herba-alba L., Ruta montana L., GC-MS analysis.
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DOI:
http://dx.doi.org/10.19261/cjm.2017.410

Abstract (PDF)
Supplementary Material (PDF)
Graphical Abstract: Essential oils were extracted from Artemisia herba-alba L. and Ruta montana L. by means of steam distillation and thionated with a reagent combination of phosphorus pentasulfide and sodium bicarbonate. Both parent essential oils and their modified ones were screened for their biological and insecticidal activities. The results showed that essential oils were composed mainly of ketones; essential oils from Artemisia herba-alba L. and those from Ruta montana L. consisted of bicyclic monoterpenes and acyclic aliphatic ketones (thujone, camphor and 2-undecanone), respectively. The antimicrobial activity of essential oils was substantially improved upon thionation (from 10 to 34 mm and from 11 to 32 mm). The insecticidal effect of the thionated essential oil from Ruta montana L. was observed to be very significant, but that of the essential oil from Artemisia herba-alba L. was observed to decrease (from 100% to 70% after 24 hrs. The extracted essential oils as well as their thionated forms were characterized by GC-MS, FT-IR, and UV-visible.





Downloads: 74

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.



 

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THE EFFECT OF STARTER CULTURE PRODUCING EXOPOLYSACCHARIDE ON PHYSICOCHEMICAL PROPERTIES OF YOGHURT

Author(s):

Anatoli Cartasev, Valeriu Rudic


Field: Food chemistry
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 7-12
Keywords: yoghurt, starter culture, Streptococcus thermophilus, physicochemical properties.
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DOI:
http://dx.doi.org/10.19261/cjm.2017.440   
 
Abstract (PDF)
Graphical Abstract: The purpose of this research was to investigate the impact of indigenous starter culture capable to synthesize exopolysaccharides (EPSs) on physicochemical properties of yoghurt. Two starter cultures, EPS-producing and non-EPS-producing, were developed from the autochthonous lactic acid bacteria strains by pairwise combining Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus strains. In the present study the ropy strain of Streptococcus thermophilus CNMN LB-50 was incorporated in EPS-producing starter culture. The microstructure, viscosity, EPS amount, structural properties and syneresis of yoghurt samples were assessed. It has been established that the EPS-producing starter culture provided a reduction of structural degradation and increased degree of structural recovery after deformation. Besides, it was observed that the use of EPS synthesized starter culture in yoghurt production restrains the syneresis of the gel.

 
 

Downloads: 46