a borítólapra  Súgó epa Copyright 
European chemical bulletinVol. 1, No. 1-2 (2012)



  • Content48en [52.33 kB - PDF]EPA-02286-00001-0010

Industrial and engineering chemistry

Classical chemical sciences

  • Lakatos Györgyi ,
    Pradep K. Sharma ,
    Vinita Sharma ,
    Bálint Szabolcs ,
    Raj N Mehrotra :

    The composition of chlorine hydrates synthesised by different reaction routes were determined from experimentally measured densityvalues without isolating the gas hydrate crystals. This method is the simplest and accurate for determining the composition of chlorinehydrates prepared under various conditions. The occupancies of each type of the cavities in the clathrate cage have been calculated.

  • Vass Gábor ,
    Dzsotján Dániel ,
    Lajgut Győző György ,
    Pasinszki Tibor :

    Disubstituted furoxans, 1,2,5-oxadiazole-2-oxides (X2C2N2O2, where X= H, Cl, Br, I, CH3, NC), have been investigated in the gas phase by He I and He II UV photoelectron spectroscopy. Ionization potentials have been determined and the electronic structures have been discussed within the frame of molecular orbital theory. The ground-state geometries of the neutral molecules have been obtained from quantum-chemical calculations using the B3LYP/cc-pVTZ method. Photoelectron spectroscopy, supported by quantum-chemical calculations at the SAC-CI/cc-pVTZ level, provides a detailed investigation into the electronic character of the molecules and an analysis of the effect of substitution on the orbitals of the parent furoxan.

  • Sajó E. István :
    Characterization of synthetic voltaite analogues35-36en [137.28 kB - PDF]EPA-02286-00001-0060

    Recently new NH4- and Mg-containing minerals of the voltaite group have been discovered. As they were found in minute amounts and are intimately intergrown with their associated minerals, a number of their properties could not be measured and characterized properly. The four pure end members of the solid solution series were synthetized and characterized, that made possible the reliable identification of natural solid solutions within the boundaries of this phase composition range.

Materials and environmental chemistry

  • Anurag Saini ,
    Kótai László ,
    Sajó E. István ,
    Szilágyi Imre Miklós ,
    Lázár Károly ,
    May Zoltán ,
    Fazekas Péter ,
    Gács István ,
    Sharma Vinita ,
    Banerji Kalyan K :

    The scarcely reactive zinc ferrite can be decomposed in solid phase to water-soluble ZnSO4 and water-insoluble Fe2O3polymorphs byexcess of solid iron(II or III) sulphates at 650°C in 4 h. Since SO3 forms in situ from the Fe2(SO4)3 as well as anhydrous Fe2(SO4)3 formsin the thermal oxidation of iron(II) sulphate, therefore the gaseous SO3 is the active sulphatization agent in the reaction of thehydrated iron(II and III) sulphates and the zinc ferrite. The sulphatization process were monitored by XRD, TG/DTA-MS, Mössbauer,Raman and IR-spectroscopy and the changes in reaction’s heat and Gibbs energy are reported. The Fe2O3 polymorphs formed is worthprocessing into iron(III) sulphate by sulphuric acid. Since the Fe2(SO4)3formed in this way can be recycled to the sulphatization process,the only reagent consumed is the sulphuric acid. Therefore, these selective sulphatization reactions can be taken as “iron salts mediated”decompositions of zinc ferrite into ZnSO4 and Fe2O3 by sulphuric acid.

Biochemistry, molecular biology and biotechnology

  • Szentmihályi Klára ,
    May Zoltán ,
    Then Mária ,
    Böszörményi Andrea ,
    Balázs Andrea ,
    Lemberkovics Éva ,
    Marczal Gabriella ,
    Szőke Éva :

    Beside plant drugs the application of herbal mixtures using in several indication fields is very popular in our time. Since these herbal mixtures contain several bioactive agents, their analysis may cause difficulties. Therefore the description of measurements of components and their standardization is generally missing from the Pharmocopoeias. The examined Species thymi composita (STC) is highly effective because of its cholagog, carminative, expectorant, anticatarrhal etc. activity. STC is the mixture of Althaeae radix et folium (marshmallow leaf and root), Verbasci flos (mullein flores), Liquiritiae radix (liquorice root) and Thymi herba (thyme). The macroscopic and microscopic identification of components, phytochemical characterization have been described, the element composition of the herbal mixture, plant drugs constituents and teas was studied and the in vitro element absorption was examined. It has been stated that the STC could be characterized by its mucilage content and volatile oil composition. STC and its tea contain elements as well and the in vitro absorption of some of elements showed relatively high amount. The presence of bioactive compounds, volatile oil components, mucilage and elements may be jointly important in the complex effect, although the relatively higher Mg and Zn content in the tea is particularly relevant that acts via signal transduction process.

  • Tóth Anita ,
    Riethmüller Eszter ,
    Alberti Ágnes ,
    Végh Krisztina ,
    Kéry Ágnes :

    A comparative qualitative and quantitative screening of phenoloids of Lysimachia vulgaris L., Lysimachia nummularia L. and Lysimachia punctata L. is reported for the first time. The total flavonoid, hydroxy-cinnamic acid, tannin and polyphenol content of these species were examined by spectroscopic methods (Ph. Eur. 5.). The accumulation of the various phenoloids in individual organs was investigated as well. The quantitative analytical measurements revealed that the total flavonoid content expressed in hyperoside of L. vulgaris was significantly lower than of the samples of L. nummularia, and L. punctata, but its hydroxycinnamic acid content was outstanding. The accumulation of polyphenols and tannins showed to be homogeneous among the samples. The in vitro radical scavenging activities of the plant extracts were tested by DPPH and ABTS methods. Our studies proved that L. nummularia extract had the most significant activity. Investigations on the correlation between the composition of flavonoids in the samples and their in vitro antioxidant effect showed that the dominance of myricetin glycosides in L. nummularia is closely related with the most significant antioxidant capacity of this sample. In addition to the quantitative accumulation of flavonoids, significant differences have been observed in the composition of their quality as well. The main flavonoids in L. nummularia and L. vulgaris were identified as myricetin- and myricetin- quercetin-, and kaempferol-glyosides respectively using HPLC-DAD-ESI-MS/MS method.

  • Árok Renáta ,
    Végh Krisztina ,
    Alberti Ágnes ,
    Kéry Ágnes :

    Bergenia crassifolia L. (Fritsch.) and Bergenia cordifolia Sternb., species of Saxifragaceae are decorative perennial plants. The most characteristic compound with biological activity is arbutin with skin whitening properties. Arbutin from other sources is used in skin pigmentary disorders. The aim of our work was the identification and qualitative analysis of arbutin using HPLC, UV-spectra and standard addition methods and quantitative determination of arbutin and other pharmaceutically interesting compounds: flavonoids, hydroxicinnamic acids, polyphenols and tannins in domestic cultivars, considering the synergism of phytochemical agents in therapeutic effect in skin disorders.

Theoretical and nuclear chemistry

  • Kótai László ,
    Lippart József ,
    Gács István :

    Deuterium isotope separation process takes place in the reaction of the amalgamated aluminium metal surface and water. The reaction produces hydrogen gas with ~40 ppm deuterium content and the formed aluminium hydroxide gel is enriched in deuterium. The theoretical separation factor is s=3.9. Besides the kinetic isotope effect, the key factor in the separation process is the H2O+HD=HDO +H2 exchange reaction. Since only a low amount of amalgam forms on the aluminium surface, the overvoltage difference of the deuterium and the hydrogen on the mercury does not play key role in the process. The main role of the amalgam formation is embodied in the decomposition of the stable oxide layer on the aluminium surface, thus ensuring free metallic surfaces for the reaction with the water.

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