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    Characterization of Bulgarian oil shale kerogen revealed by oxidative degradation
    (Elsevier GMBH, Urban & Fischer Verlag, 2009) Budinova, Temenuzhka K.; Razvigorova, Maria; Tsyntsarski, Boyko G.; Petrova, Bilyana N.; Ekinci, Ekrem; Yardım, Mehmet Ferhat
    A 13-step alkaline permanganate degradation of Bulgarian oil shale kerogen concentrate at ambient temperature was carried out. A high yield of oxidation products (90.1%) and a low yield of gaseous products (2.79%) were obtained. IR and (1)H NMR spectroscopic studies have shown that two significantly different types of high molecular products are present in kerogen. Further oxidation of these structures leads to the formation of low molecular aliphatic and aromatic acids, proven by gas chromotography (GC) and gas chromatography-mass spectrometry (GC-MS). The data obtained at these mild conditions allow us to acquire detailed information about the aromatic structures and polymethylene chain lengths in kerogen.The 5-step oxidation of the kerogen at 90 degrees C provides information about stable aromatic structures. Soluble and insoluble polyfunctional acids in acid medium have close molecular masses and spectral characteristics. The amount of benzene and naphthalene carboxylic acids is 11.3% of the organic matter of the oil shale.
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    The composition of acids in bitumen and in products from saponification of kerogen: Investigation of their role as connecting kerogen and mineral matrix
    (Elsevier Science BV, 2008-11-03) Razvigorova, Maria; Budinova, Temenuzhka K.; Tsyntsarski, Boyko G.; Petrova, Bilyana N.; Ekinci, Ekrem; Atakül, Hüsnü
    In order to obtain more information and to understand the nature of relation between organic and mineral matter in oil shales, the compositions of soluble bitumen fractions obtained by extraction from Bulgarian oil shales before and after demineralization with 10% HCl, concentrated HE and a HF/HCl mixture were investigated. The four extracts were quantitatively examined by IR and H-1 NMR spectroscopy. The investigation of isolated acidic material of the bitumen fractions showed that the fatty acids are present in bitumen fractions as free acids, esters and salts. The amount of free acids in bitumen is very small. The dominant part of bitumen acids is associated with mineral components of the oil shales as well as part of them is included in the mineral matrix, and can be separated only after deep demineralization. The kerogen of the oil shales, obtained after separation of the bitumen fractions and mineral components, was subjected to saponification in order to determine the amount of acids, bound as esters to the kerogen matrix. The major components found were n-carboxylic, alpha,omega,-di-carboxylic, and aromatic acids. The connection of kerogen with mineral components is accomplished by the participation of carboxylic and complicated ester bonds. Experimental data for the composition of bitumen acids give evidence that algae and terrestrial materials are initial sources in the formation of soluble organic matter of Bulgarian oil shale.
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    Thermochemical conversion of bean pods to carbon materials and gas
    (Freund Publishing House Ltd, 2008) Ekinci, Ekrem; Budinova, Temenuzhka K.; Tsyntsarski, Boyko G.; Petrova, Bilyana N.; Yardım, Mehmet Ferhat; Cabal, Belén; Ania, Conchi O.; Parra, Jose B.
    The preparation of activated carbons from bean pods by chemical (K(2)CO(3)) and physical (water vapor) activation was investigated. The carbon prepared by chemical activation presented more developed porous structure than one obtained by water vapor activation. Carbon adsorbent with very low ash content and developed micropore structure is obtained by thermochemical treatment with conc.H(2)SO(4) of liquid products from carbonization of bean pods and activation with water vapour.