Chemistry Journal of Moldova

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. 



 

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 Mn^III-Mn^II-Mn^IIIcore, where a ferromagnetic coupling (J = 2.62 cm^–1) between the Mn^III and Mn^II ions.


 

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.

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.


 

DOI: http://dx.doi.org/10.19261/cjm.2017.410

Abstract (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.

 
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.



 

 

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.

 

 

DOI: dx.doi.org/10.19261/cjm.2017.406

 

Abstract (PDF)
Graphical Abstract: This paper presents the study regarding the impact of the treatment with Câmpeni red petroleum on an eighteenth-century icon made of wood, with the aim of active preservation and restoration. In accomplishing this endeavour, there were applied non-invasive techniques of analysis based on optical microscopy (OM), Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray analysis (EDX), micro-FTIR and colorimetry CIEL*a*b*. A series of chemical, physical-structural and mechanical characteristics of the wood were traced, in order to assess the degree of preservation enhancement as a result of the applied treatment.

DOI: dx.doi.org/10.19261/cjm.2017.401

 

Abstract (PDF)
Graphical Abstract: Composite lignocellulose-inorganic sorbents derived from plant residues of agriculture and food industry, modified with ferrocyanides of d-metals and hydrated antimony pentoxide were prepared. Caesium and strontium ions removal from water was tested by radiotracer method. Sorption of heavy metal ions, methylene blue, gelatin, vitamin B₁₂ was also studied.

DOI: dx.doi.org/10.19261/cjm.2017.376 

 

Graphical Abstract: Eight new aliphatic symmetrical diphosphonium salts were synthesized by reacting ω,ω´-dibromoalkanes with triphenylphosphine or tributylphosphine using N,N-dimethyl acetamide as a solvent at 140~150°C for 16~20 h under a nitrogen atmosphere.