Chemistry Journal of Moldova

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.


 

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.


 

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.

 

 

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 I^₃- 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 IO^₃-, 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.

 
 

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.

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.

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.


 

 
Abstract (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.



 

DOI: dx.doi.org/10.19261/cjm.2017.408   

 

Abstract (PDF)
Graphical Abstract: In this paper, anodic oxidation of sulphite ions on smooth nickel based 6 layers platinum nanoparticles electrode in aqueous alkaline solution was investigated in order to clarify the oxidation mechanism and to find optimal parameters for sulphite oxidation process, by applying various electrochemical methods of analysis.