Chemistry Journal of Moldova

2011 Volume 6, no.2

PHYSICOCHEMICAL PROPERTIES OF THE GASOLINE AND ALCOHOL BIOFUEL MIXTURES

Author(s):

I. Povar, V. Cerempei and B. Pintilie


Field: Analytical chemistry
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 48-52
Keywords: alcohol, biofuel, distillation curves, gasoline, Reid saturated vapour pressure, specific gravity.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2011.06(2).11

Graphical Abstract:
 The influence of added alcohols, ethanol and butanol, on the main biofuel properties, such as the specific gravity, Reid saturated vapour pressure and distillation curves have been investigated. These properties are intimately related to the fuel composition and their prediction relies on the knowledge of its components characteristics. This research proves the possibility of obtaining fuels with different levels of resistance to detonation, using gasoline with different chemical components and various fractions of alcohols.

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STUDY CONCERNING THE POSSIBILITY OF GAMMA-SPECTROSCOPY METHOD TO DETERMINE THE TOTAL POTASSIUM IN SOILS

Author(s):

Tamara Leah, Zoia Lozovaia


Field: Ecological chemistry
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 53-57
Keywords: gamma-spectrometry, total potassium, 40 K, conversion coefficient, chernozems, podzolic soils.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2011.06(2).12

Graphical Abstract: 
It was proved the possibility of determination the total potassium in soils by gamma-spectroscopic method with subsequent calculation of total potassium content in according to value of 40K isotope (expressed in Becquerel, Bq), using the formula:
К2О, % = С . А, where: C – conversion coefficient, A – activity of isotope 40K in soil, Bq/kg. Conversion coefficient for chernozems of Moldova – C=0,00337.

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STUDIES ON THE ANTIOXIDANT ACTIVITY OF THE COMPOUND ENOXIL AND ITS RELATED FORMS

Author(s):

Tudor Lupaşcu, Alexandru Gonţa


Field: Ecological chemistry
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 58-64
Keywords: polyphenols, antioxidants, DPPH• , ABTS•+ .
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DOI:
dx.doi.org/10.19261/cjm.2011.06(2).13

Graphical Abstract:
 The compound Enoxil is a mixture of polyphenols, esthers, and carboxylic acids, which could be involved in reducing the risk of diseases associated with oxidative stress. The results of the investigation of antioxidant activity for the compound Enoxil and its forms are presented in this paper. It can be concluded that acetone-Enoxil has a higher antioxidant activity that other tested compounds.

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ANALYSIS OF THE PHTHALATE CONTENT LEVELS IN WINE PRODUCTS

Author(s):

Duca Gheorghe, Sturza Rodica, Gaina Boris, Lazacovici Dmitri


Field: Food chemistry
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 65-69
Keywords: phthalates, wine, gas-chromatography, mass-spectrometry, dibutylphthalate.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2011.06(2).14

Graphical Abstract:
 In the context of studies conducted in the laboratory of National Center for Quality Testing of the Alcoholic Beverages (Republic of Moldova) were included more than 1300 samples of the bottled wine and base-wine for the presence of most widespread and toxic phthalate – dibutylphthalate using modern method of analysis like GC-MS. Results display presences DBP in 85 % of studied samples of wines, i.e. a content of DBP more than LOQ (0.01mg/dm3). Has been determined that contamination of phthalates has a technogenic character, and it is the result of contact with polymeric materials. Optimum conditions of extraction DBP from liquid samples were obtained.

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COORDINATION COMPOUNDS OF NICKEL(II), COPPER(II) AND COBALT(II) BASED ON S-METHYLISOTHIOSEMICARBAZIDE AS DYES FOR THERMOPLASTIC POLYMERS

Author(s):

Ştefan Manole, Maria Cocu


Field: Inorganic and coordination chemistry
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 70-72
Keywords: coordination compounds, transition metals, dyes, thermoplastic polymers.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2011.06(2).15

Graphical Abstract:
 We have researched the color properties of coordination compounds synthesized by us previously [1] (8-(1',2'-naphthyl)-1-
R3-methyl-6-thiomethyl-4,5,7-triazaocta-1,3,5,7-tetraenato-1,1'-diolato(-)O, O', N4, N7-M(II), where R=CH3, C6H5, M=Ni, Co, Cu), which can be used for coloring thermoplastic masses. They meet the requirements for use as a pigment for coloring thermoplastic masses.

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SYNTHESIS AND SPECTROSCOPIC STUDY OF SOME COORDINATIVE COMPOUNDS OF Co(III), Ni(II) AND Cu(II) WITH DIANILINE- AND DISULFANILAMIDEGLYOXIME

Author(s):

Andrei Rija, Ion Bulhac, Eduard Coropceanu, Elena Gorincioi, Elena Calmîc, Alic Barbă, Olga Bologa


Field: Organic chemistry
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 73-78
Keywords: α-dioximes, coordinative compounds, 3d metals, spectroscopy.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2011.06(2).16

Graphical Abstract: 
Directed synthesis of dianiline- (DAnH2) and disulfanilamideglyoximes (DSamH2) has been accomplished by condensation of dichloroglyoxime with aniline or sulfanilamide in 1:2 molar ratio, as well as their corresponding Co(III), Ni(II) and Cu(II) coordinative compounds. Composition, structure and some properties of dioximes and complexes have been established by using elemental analysis, UV-Vis, IR and NMRspectroscopies. Dioxime coordination at the central atom and structure of complexes depends on pH of reaction medium: at pH=5-6 - bis-dioximates, whilst at pH=2 – tris-dioximines are obtained.

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SYNTHESIS AND PHOTOOXYGENATION OF THE METHYL ESTER OF 11-HOMODRIM-6,8(9)-DIENE-12-OIC ACID

Author(s):

Biriiac Andrei


Field: Natural product chemistry and synthesis
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 79-83
Keywords: homodrimanes, synthesis, photooxygenation.
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AB INITIO STUDY OF CHEMICAL ACTIVATION AND HYDROGENATION OF WHITE PHOSPHORUS IN REACTION WITH RHODIUM TRIHYDRIDE COMPLEX

Author(s):

Iolanta I. Balan, Natalia N. Gorinchoy


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 84-90
Keywords: white phosphorus, triphos, rhodium trihydride complex, ab initio calculations.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2011.06(2).18

Graphical Abstract:
 The four-stage mechanism of reaction of the rhodium trihydride complex [(triphos)RhH3] (triphos=1,1,1-tris(diphenylphosphanylmethyl)ethane) with the white phosphorus molecule resulting in the phosphane and the cyclo-P3 complex [(triphos)M(η3-P3] is analyzed on the basis of ab initio calculations of reactants, products, and intermediate complexes of reaction. It is shown that generation of the transient complex  [(triphos)RhH(η1:η1-P4)] followed by intramolecular hydrogen atom migration from the metal to one of the phosphorus atoms is the energetically favourable process. Calculations also show that P4 molecule is activated by coordination to the above complex: the metal-bonded P-P edge is broken, and the tetrahedron P4 is opened to form the butterfly geometry. This activation is realized mainly due to the one-orbital back donation of 4d-electron density from the atom of Rh to the unoccupied antibonding triple degenerate t1*-MO of P4.

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PHARMACEUTICAL AMORPHOUS ORGANIC MATERIALS CHARACTERIZATION BY USING THE DIFFERENTIAL SCANNING CALORIMETRY AND DYNAMIC MECHANICAL ANALYSIS

Author(s):

Ion Dranca, Igor Povar and Tudor Lupascu


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2011 Volume 6, no.2
Pages: 91-95
Keywords: DSC –differential scanning calorimetry; DMA –dynamic mechanical analysis; drugs; excipients; glass transition; α- and β –relaxations; crystallization; kinetics.
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Abstract (JPEG)

DOI:
dx.doi.org/10.19261/cjm.2011.06(2).19

Graphical Abstract:
 This research has been carried out in order to demonstrate the use of differential scanning calorimetry (DSC) in detecting and measuring α- and β-relaxation processes in amorphous pharmaceutical systems. DSC has been employed to study amorphous samples of poly (vinylpyrrolidone) (PVP), indomethacin (InM), and ursodeoxycholic acid (UDA) that are annealed at temperature (Ta) around 0.8 of their glass transition temperature (Tg). Dynamic mechanical analysis (DMA) is used to measure β- relaxation in PVP. Yet, the DSC has been used to study the glassy indomethacin aged at 0 and -10 oC for periods of time up to 109 and 210 days respectively. The results demonstrate the emergence of a small melting peak of the α-polymorph after aging for 69 days at 0°C and for 147 days at -10°C (i.e., ~55°C below the glass transition temperature) that provides evidence of nucleation occurring in the temperature region of the β-relaxation.

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