“…Numerous unsubstituted and alkyl-substituted aliphatic tricarboxylic acids and a very small amount of 1,2,3,4-butanetetracarboxylic acid were recovered from the aqueous phase (Figure , Table ). Although these acids were also resolved among the RICO products of coals, ,, no previous study reported the formation of these acid structures in the case of heavy-oil fractions. These acids should be formed from three or more aryl-substituted alkyl bridges, and some of them may be formed from alicyclic parts of partially saturated condensed structures. ,, …”
Section: Resultsmentioning
confidence: 95%
“…In general, alkyl-substituted aromatics are oxidized to CO 2 except at the site of the alkyl attachment, which is converted to a carboxylic group anchored to the alkyl chain, resulting in the formation of an alkanoic acid. Alkyl groups attached on methano bridge sites can also produce alkanoic acids. ,,− …”
Section: Resultsmentioning
confidence: 99%
“…In general, unsubstituted diacids dominate over the alkyl-substituted analogues. While these acids represent alkyl bridge structures connecting two aryl units and α,α,ω-triaryl substituted bridges, however, short-chain diacids (C 4 −C 6 ) may also arise from oxidation of various hydroaromatic structures. ,,, Other minor peaks appearing in the valleys of the main series inferred branched and terpenoid acid esters. As in the case of the RICO reaction of a bituminous coal, the asphaltene sample also yielded ethanedioic acid by the RICO reaction .…”
Ruthenium-ion-catalyzed oxidation (RICO) was used to investigate the structural details of an asphaltene sample. The oxidation products consisted of homologous series of straight-and branched-chain monocarboxylic acids, dominated by C 2 -C 4 acids. Aliphatic di-and polycarboxylic acids were also resolved, confirming the presence of polymethylene moieties linking two or more aromatic units. The detection of ethanedioic acid among the oxidation products indicates the importance of biaryl linkages within the asphaltene. Large amounts of a polymeric aliphatic fraction were also recovered after RICO reaction. The recovery of benzene polycarboxylic acids and a high molecular weight aromatic acid fraction, along with NMR analyses of the original asphaltene, indicates that the asphaltene molecule is comprised of relatively large polycondensed aromatics and hydroaromatic units.
“…Numerous unsubstituted and alkyl-substituted aliphatic tricarboxylic acids and a very small amount of 1,2,3,4-butanetetracarboxylic acid were recovered from the aqueous phase (Figure , Table ). Although these acids were also resolved among the RICO products of coals, ,, no previous study reported the formation of these acid structures in the case of heavy-oil fractions. These acids should be formed from three or more aryl-substituted alkyl bridges, and some of them may be formed from alicyclic parts of partially saturated condensed structures. ,, …”
Section: Resultsmentioning
confidence: 95%
“…In general, alkyl-substituted aromatics are oxidized to CO 2 except at the site of the alkyl attachment, which is converted to a carboxylic group anchored to the alkyl chain, resulting in the formation of an alkanoic acid. Alkyl groups attached on methano bridge sites can also produce alkanoic acids. ,,− …”
Section: Resultsmentioning
confidence: 99%
“…In general, unsubstituted diacids dominate over the alkyl-substituted analogues. While these acids represent alkyl bridge structures connecting two aryl units and α,α,ω-triaryl substituted bridges, however, short-chain diacids (C 4 −C 6 ) may also arise from oxidation of various hydroaromatic structures. ,,, Other minor peaks appearing in the valleys of the main series inferred branched and terpenoid acid esters. As in the case of the RICO reaction of a bituminous coal, the asphaltene sample also yielded ethanedioic acid by the RICO reaction .…”
Ruthenium-ion-catalyzed oxidation (RICO) was used to investigate the structural details of an asphaltene sample. The oxidation products consisted of homologous series of straight-and branched-chain monocarboxylic acids, dominated by C 2 -C 4 acids. Aliphatic di-and polycarboxylic acids were also resolved, confirming the presence of polymethylene moieties linking two or more aromatic units. The detection of ethanedioic acid among the oxidation products indicates the importance of biaryl linkages within the asphaltene. Large amounts of a polymeric aliphatic fraction were also recovered after RICO reaction. The recovery of benzene polycarboxylic acids and a high molecular weight aromatic acid fraction, along with NMR analyses of the original asphaltene, indicates that the asphaltene molecule is comprised of relatively large polycondensed aromatics and hydroaromatic units.
“…It is well known that ruthenium (VIII) oxidant selectively attacks sp 2 carbon of aromatic rings (Murata et al, 1994), but it cannot nearly oxidate alkyl chains and alkyl bridges connected to aromatic rings. Various connections of aliphatic chains can give special monoaliphatic acids and aliphatic polycarboxylic acids (Choi et al, 1988). Based on this analysis, the connection forms and amount of saturate groups in structure can be deduced.…”
The structure of coke from five spent residue hydrotreating catalysts was investigated based on ruthenium ion catalyzed oxidation reaction. The distribution of n-alkyl chains and bridges attached to aromatic carbon of coke on catalysts was quantified. Results showed the concentrations of n-alkyl chains and bridges in coke were declined with the increase of carbon number. The substituential group is methyl mainly, and it had no >C 5 alkyl chains in coke. Various isomeric benzenepolycarboxylic acids from oxidated products were identified. Then the condensation mode of some aromatic structure was discussed. The precursor of coke affected the coke structure. Catalysts made coke dehydrogenate to form graphite type aromatic condensate. About 60% of coke was graphite type.
“…Αντίθετα τόσο στον Χουµινίτη, όσο και στον Ινερτινίτη επικρατούν οι περισσότερο αρωµατικοί C-H δεσµοί Wang, 2000, Sun et al, 2003), που έχουν ως αποτέλεσµα η αύξηση της συγκέντρωσης των συγκεκριµένων maceral να οδηγεί κατά την πυρόλυση σε µείωση των εκλυόµενων ελαφρών υδρογονανθράκων. Οι Choi et al (1988), Lester (1994), Guo et al (1996) και Orem and Finkelman (2004) (Cumming andMcLaughlin, 1982, Benfell et al, 1996).…”
The intense post-Alpine activity in Greece during Neogene and Quaternary had as a result the formation of many intermontane and paralic basins. The largest Greek lignite deposits were formed from Neogene to Pleistocene in intermontane basins (Ptolemais, Florina, Drama, Megalopolis) while the lignite deposits of paralic origin are smaller in thickness and size. Around 67% of the exploited Greek coal deposits are located in Florina-Ptolemais-Servia basin in west Macedonia while Megalopolis deposit in Peloponnesus peninsula, in southern Greece is also under exploitation. Lignite is mined in open pits and is used mainly for electricity production (~ 62-63% of the total energy demands).The objective of the present doctoral thesis is to study the behavior of lignites coming from the main Greek lignite basins under pyrolysis conditions. We emphasized on the effect the macroscopic and coal petrographic characteristics have on the pyrolysis mechanisms and also studied the liberation of CO, CO 2 , H 2 , CH 4 and Ν 2 during open system non-isothermal pyrolysis. A number of analytic methods such as Fourier Transform Infrared Spectroscopy (FTIR), Rock Eval II pyrolysis and thermal analyses (TG/DTA) were also performed in an effort to collect more data and investigate the correlations between them. Samples were taken from exploration wells in two basins: the Florina-Ptolemais-Servia basin (deposits of Komanos, Klidi, Proastio, Prosilio and Notio Pedio) in W. Macedonia and the Megalopolis basin (deposits of Kyparissia and Marathousa) in Peloponnesus, where the main Greek coal deposits are located and exploited by the Greek Public Power Corporation (P.P.C.). According to macroscopic observations matrix lignite is the dominant lithotype for samples coming from Komanos, Proastio and Notio Pedio while those of Klidi and Prosilio can be of either xylitic or matrix lithotype. On the other hand, samples from Kyparissia and Marathousa mostly belong to the mineral rich lithotype.Proximate analysis included the determination of moisture, ash and volatile matter while the calorific value of lignites was also measured. In samples from W. Macedonia moisture 'as received' ranges from 31.0-64.5%, ash on dry basis is 8.7-45.5%, volatile matter on dry basis range from 37.2% to 58.5% and calorific value on an ash-free dry basis is 3,851-6,735 kcal/kg. In lignites from Megalopolis 'as received' moisture range from 38.9-67.3%, and ash on dry basis is 28.4% to 48.5%. Volatile matter on a dry basis range from 33.7% to 46.8% and calorific value on an ash-free dry basis is around 2,473-4,897 kcal/kg.x During ultimate analysis the percentage of carbon, hydrogen, nitrogen, sulfur and oxygen was determined. For the lignites of W. Macedonia the above values range from 32.3-59.3%, 2.5-5.9%, 0.5-2.2%, 0.4-3.9% and 13.0-34.3% respectively, while for the Megalopolis lignites the values are 17.2-42.4%, 2.0-3.8%, 0.9-1.5%, 2.6-5.6% and 10.2-28.8% respectively. From the proximate and ultimate results it was concluded that samples from W.Macedonia are classifi...
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