Volume 6, No. 2 (2005)
Articles
APPROCHES SYNTHÉTIQUES VERS LES ARISTOLACTAMES – PARTIE II. CONNEXION À L`AZOTE LACTAMIQUE DE SEGMENTS HYDROCARBONÉS AMINÉS
RYBALKO-ROSEN HÉLÉNE, COUTURE AXEL, GRANDCLAUDON PIERRE*
The synthesis of a variety of polyalkoxylated aristolactams further equipped with dialkylamino chain on the lactam nitrogen atom is described. The synthetic tactics relies upon the preliminary elaboration of phosphorylated isoindolinones bearing either the requisite amino functionality or easily transformable acetal groups. Horner reaction and radical cyclization of the resulting arylmethylene isoindolinones which are also accessible by an alternative synthetic route then complete the synthesis of the target compounds.
ISOCRATIC AND GRADIENT CONDITIONS FOR INORGANIC CATIONS ANALYSIS BY REALIZATION ON-LINE COUPLING OF ION EXCHANGE CHROMATOGRAPHY WITH EVAPORATIVE LIGHT SCATTERING DETECTOR
EL HADDAD M.(1)AND(2), BOULAHJAR R.(2)AND(3), MAMOUNI R.(2), EL ANTRI S.(3), AKSSIRA MOHAMED(2), DREUX M.(4), LAZAR S.(3)*
Performances of three available commercials cationic exchangers: Lichrosil IC CA2 Merck, Metrosep cation 1-2 Metrohm and PRP-X200 Hamilton for ion exchange chromatography were compared. Isocratic conditions were developed for inorganic cations (Na+, K+, Mg2+ and Ca2+) separation on Metrosep cation 1-2 and Lichrosil IC CA2 columns in about 6 min and 3 min, respectively using proton as ion developer. While, ammonium was used as ion developer for inorganic cations separation with step gradient on PRP-X200 Hamilton column in about 10 min. Retentions of inorganic cations on these chromatographic supports were discussed. Evaporative light scattering detector was used as detection system. The developed method provides good linearity for the calibration curves, and enables a 10 ng absolute detection limit for Na+, Mg2+ and Ca2+ and a 25 ng absolute detection limit for K+, at a signal-to-noise ratio of 3.
SYNTHESIS AND COMPLEXING PROPERTIES OF NEW POLYETHER MACROCYCLES CONTAINING THE ANTHRAQUINONIC SYSTEM
NABIL A.(1), QERRICH H.(2), KANDRI RODI Y.(2), EL HADRAMI E. M.(2), PIERROT M.(3), ESSASSI E. M.(1)*
We describe the synthesis of the new open system 3 and polyether macrocycles containing an anthraquinonic system 4 and 5; their sulphur compounds 6 and 7 have also been prepared. X-Ray crystallographic study of compound 5 in the presence of calcium and barium perchlorates shows that the latter crystallizes into monoclinic and triclinic system respectively. The UV spectrometry shows that the macrocycle 5 presents complexing properties toward Ca2+, Ba2+ and Pb2+ ions. By contrast macrocycle 4 selectively complexes Pb2+ ions; these complexes were observed by electrospray, IR and UV spectrophotometry.
INVESTIGATIONS ON THE THERMAL BEHAVIOR OF SOME FERROCENE DERIVATIVES WITH LIQUID CRYSTALLINE PROPERTIES
APREUTESEI DANIELA(1), LISA GABRIELA(1)*, HURDUC NATALIA(2), SCUTARU DAN(1)
Thermal stability depends on the nature of functionalities within a molecule. Such considerations are of great importance for industrial applications, especially when processing at high temperature is required. In the case of organometallic molecules, the major factor in inducing special properties is the presence of a metal, which might confer not only its properties but also geometries rarely found in purely organic compounds. Kinetics of thermal behavior, at three heating speeds 6.5, 10 and 14.5 K/min of sample 1 and sample 2 have been studied [1]: The thermostability has been established by applying thermal criterions. The processing of ATG data by integral methods was carried out, following the activation energy – transformation degree dependence and the evolution of the nucleation process.
KINETICS OF RELEASE OF CHLORAMPHENICOL INTERCALATED IN HYDROTALCITE
FRUNZĂ MIHAELA*, POPA MARCEL, CARJA GABRIELA
This paper reports the kinetic study of the release of chloramphenicol (CFN) intercalated in hydrotalcite. The release of CFN anion from the lamella of an organic-inorganic nanohybrid material, MgAl LDH_CFN nanocomposite, was found to be pH dependent. The release of CFN from the lamella of hydrotalcites at pH 2.0 was controlled by firstorder kinetics. Microbiological tests with Staphylococcus Epidermidis demonstrated an antimicrobial activity for a period of 48 h.
EXPERIMENTAL DYNAMIC VISCOSITIES OF BINARY MIXTURES: ACETIC ACID + WATER, BENZENE, TOLUENE, n – HEXANE, n – HEPTANE AT 296.15, 302.15, 308.15, 314.15 AND 319.15 K
BOLAT GEORGIANA, LISA GABRIELA*, POPA MARCEL
This paper reports the dynamic viscosities of acetic acid + water, benzene, toluene, n-hexane and n-heptane at five temperatures in the range of 230C to 460C throughout the whole concentration range. The viscosity deviations were calculated from experimental data and fitted to a Redlich-Kister polynomial function. Results were analyzed in terms of molecular interactions.
INHIBITION CORROSION OF EUGENOL ON THE CORROSION OF TITANIUM-NICKEL IN PHYSIOLOGICAL MEDIA
CHAOUKI HAKIMA, ABDELILAH CHTAINI*
The effect of addition of (2-methoxy 4-allyl phenol), eugenol, on the corrosion of Titanium-Nickel (TiNi) in physiological media was investigated through electrochemical impedance spectroscopy (EIS), free potential, potentiodynamic polarization curves and gravimetric measurements. The obtained results showed that eugenol revealed a good corrosion inhibitor. The inhibition efficiency depends on both the nature of treatment and concentrations of eugenol. Scanning electron microscopy (SEM) of the TiNi revealed that eugenol is adsorbed on the surface of TiNi.
PITTING CORROSION OF A DENTAL COPPER ALLOY IN ARTIFICIAL SALIVA
UNGUREANU GINA(1)*, MARECI DANIEL(1), AELENEI DELIA(1), MÎRZA ROŞCA JULIA C.(2)
The corrosion behaviour of a copper based dental alloy (GAUDENT) in a simulated saliva environment was studied by potentiodynamic polarization and by electrochemical impedance spectroscopy (EIS). It was established that the metallurgical processing (melting in air and manually casting) influences negatively the corrosion resistance. The keeping of this alloy in solution reduces the thermodynamic tendency to corrosion but not influence appreciably the type and intensity of the corrosion. In all cases a pitting corrosion was evidenced.
ELECTRODIALYSIS OF AMMONIUM SULFATE SOLUTIONS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELLING
SIMINICEANU ILIE*, COTET IOAN LUCIAN
The kinetic experimental study was carried out on a laboratory-scale electrodialysis (ED) unit of TS2-5 type from Eurodia-Tokuyama equipped with five cell pairs. The membranes used were the AMX type anion exchange membranes (AEM) and CMS type cation exchange membranes (CEM), each of 0.02 m2 surface area. The feed was an aqueous ammonium sulfate solution with molar concentrations of 88 to 92mol/m3. The evolution with time of the solution concentration in both dilute and concentrate compartments has been determined for two feed rates and four voltages, at a 303 K constant temperature. A mathematical model has been derived to describe the concentration evolution with time. The model includes two empirical constants a and b. The constants have been identified by confronting the computed data with the experimental ones. The validated model has been finally used to extrapolate the ED process in order to determine the necessary time for a practically maximal removal of ammonium sulfate. This is equivalent to a final dilute concentration of less than 1.5 mol/m3.
MATHEMATICAL MODELING OF FOLIC ACID FACILITATED PERTRACTION
BLAGA ALEXANDRA-CRISTINA(1), GALACTION ANCA-IRINA(2), CAŞCAVAL DAN(1)
Using the statistical analysis and factorial experiments of second order, two mathematical correlations for the folic acid facilitated pertraction using Amberlite LA-2 as carrier have been established. These equations describe the dependences between the solute initial mass flow, respectively the permeability factor, and the main parameters influencing the separation efficiency (pH-values of the feed and stripping phases, carrier concentration). For both cases, the considered variables control the separation process in a 96.1 - 96.8% extent, the carrier concentration exhibiting the most important influence.
INTERACTIONS FER - CASEINES DANS LES EMULSIONS ALIMENTAIRES H/E
STURZA RODICA
The work presents the study over typical food oil-in-water emulsions fortified with inorganic iron introduced as ferrous sulfate and animal proteins represented by caseins. The study includes the analysis of electro-chemical properties of emulsions depending on the environmental factors and emulsions’ stabilization by proteins as emulsifying agents.
ASPECTS REGARDING THE EVOLUTION OF RED WINES DURING THE AGING PROCESS
TITA OVIDIU
The total content in polyphenols, total acidity, and coloring intensity at the beginning and at the end of the maturation – aging process were analyzed. The samples were also analyzed from a sensorial point of view. The wines with a lower content in alcohol (11.5 – 12 % vol. alc.) undergoing a maturation – aging process, presented a lower coloring intensity, a more important decrease of the total content in polyphenols and of the total acidity, compared to the wines which were more alcoholic (13 – 13.6 % vol. alc.) and they obtained a better appreciation from a sensorial point of view. Higher levels of the wines’ acidity gaved them a better organoleptic appreciation at the end of the maturation – aging process.
RESEARCHES REGARDING THE SECONDARY FERMENTATION IN BOTTLES WITH AGGLOMERATED YEASTS
TITA OVIDIU
The yeast called 5 Agglocompact is a dry yeast, very active, which leads to a compact precipitation of the yeasts cells after the secondary fermentation ends. The conditioning of the raw material wine for the foaming agents was accomplished in the same manner as in the case of using the classical yeasts. After preparing the yeast in the vessels where the fermentation mixture was prepared, the stabilized and conditioned raw wine was introduced, then the 5 Agglocompact yeast was prepared for the triage (20 g/hL wine), then the Brilliant “liquid” for improving the fermentation and the agglomeration effect (60 mL/hL wine) and then the tannin liquid (60 mL/hL wine) to ease the foaming agent’s clarification. The quantity of raw material wine and the tirage liquid are the same as in case of using the classical fermentation. Using the 5 Agglocompact yeast determined a faster fermentation than in the classical variant, making the homogenization process easier, reducing the time for realization of the remuage with 2/3 [1].
THE EFFECT OF TEMPERATURE AND ROASTING DEGREE ON THE TOTAL PHENOLIC CONTENT OF COFFEE BREWS
BITA MIHAELA GABRIELA*, PREDA MIRCEA
Coffee has been consumed throughout the world because of its aroma, taste and physiological effects. The aim of this study was to determine changes in total phenolic content of coffee brews prepared from coffee roasted at temperatures of 200°C, 220°C and 240°C. At roasting temperature of 220°C coffee is roasted to give light, medium and dark coffee samples. The total phenolic content of coffee brews was determined by the Folin-Ciocâlteu method. The total phenolic content is depending on temperature and roasting degree. Our results suggest that light and medium roasted coffee might protect cells from damages.