Showing papers in "Petroleum Science and Technology in 1990"
TL;DR: In this paper, asphaltenes have been precipitated from a Kuwait flash residue using different n-alkanes (n-C5 to n-C8) at various temperatures ranging from 4°C to reflux temperatures of the used precipitants.
Abstract: Asphaltenes has been precipitated from a Kuwait flash residue using different n-alkanes (n-C5 to n-C8) at various temperatures ranging from 4°C to reflux temperatures of the used precipitants. Structures in the asphaltene fractions has been revealed using U.V. fluorescence spectroscopy, elemental analysis and to some extent 1H-nmr. These analysis shows that asphaltenes precipitated in the same amount but at different temperature and with different solvents have merely the same composition. For all n-alkanes the curves of precipitated amount versus temperature show maxima at about 25°C, implying a shift in the solubility of the asphaltenes.The impact of alkane chain length on the aggregation of asphaltenes through hydrogen bonds is discussed using the alkane-alcohol system as a model. The asphaltene solubility is discussed with the help of the Scatchard-Hildebrand equation.
77 citations
TL;DR: In this article, the effect of temperature, water content and acetic/formic acid concentration on the rate of corrosion of wood pyrolysis oils in presence of carbon and stainless steel plates was studied.
Abstract: A study has been conducted on the rate of corrosion of wood pyrolysis oils in presence of carbon and stainless steel plates. Tests were performed to similate the conditions existing in storage tanks. The effect of temperature, water content and acetic/formic acid concentration on the rate of corrosion of metals was studied, as well as their possible interaction effects. The method used involved a factorial design of experiments. All primary effects with their interactions were found statistically significant using the Fischer criterion at Fonx for the analysis of variance. Stainless steel resisted corrosion activity under all sets of conditions used. Wood oils were found not corrosive or slightly corrosive for cast iron at ambiant temperature and low water content, whatever the acid concentration used. Increasing the temperature to 45°C however dramatically increased the oil corrosion activity.
55 citations
TL;DR: In the presence of dissolved copper, metal deactivator additives (MDA) acted to reduce tube deposition over regions of the tube at which temperatures were higher than 250°C.
Abstract: It has been shown that metal deactivator additives (MDA) exert a strong stabilizing effect on fuels when tested in the Jet Fuel Thermal Oxidation Tester (JFTOT). At low concentrations, MDA was found to be very effective in the JFTOT in reducing insoluble reaction products but had no significant effect on fuel oxidation. In the presence of dissolved copper, MDA acted to reduce tube deposition over regions of the tube at which temperatures were higher than 250°C. The deposits formed in the presence of copper at lower temperatures, which were not reduced by the MDA, were found to contain a high concentration of copper. MDA also partially counteracted the catalytic effects of dissolved copper on fuel autoxidation.
18 citations
TL;DR: In this article, the authors used a high-resolution MS 50 Kratos spectrometer for the measurement of petroleum cuts ranging from 250 to 650°C, without any previous separation, and provided thirty-three data on the whole sample, in relation with the hydrocarbon families composition.
Abstract: Routine mode and quantitative measurements of main hydrocarbon families in petroleum cuts have managed the settinq-up of our methodology, spread over the ten last years in our lab on a high resolution MS 50 Kratos spectrometer. The technique is devoted to petroleum cuts ranging from 250 to 650°C, without any previous separation, and provides thirty three data on the whole sample, in relation with the hydrocarbon families composition, balancing From “saturates” (paraffins, cyclanes, …) to “sulfur compounds” (benzo, dibenzo, naphtalenobenzothiophenes, etc.) and including “aroroatics” scattered From mono to hepta fused structures. Checkings of the method and examples are illustrated with the help of applications picked up on petroleum processing and hydra-carbon product research topics.
16 citations
TL;DR: In this article, a retorting pilot plant with capacity of 10 kg/h using hot char as solid heat carrier was constructed and the maximum yield of tar was up to 92% of the value of Fischer Assay.
Abstract: A retorting pilot plant with capacity of 10 kg/h using hot char as solid heat carrier was constructed. This paper describes experimental results using four different lignites. The product char was used as solid heat carrier and the retorting temperature range was 450°C-670°C. The maximum yield of tar was up to 92% of the value of Fischer Assay. Produced gas and tar can be used as chemical feedstock and they are clean energy.
16 citations
TL;DR: In this article, a supercritical water/HCl system was studied for upgrading Paraho shale oil (SO) at 400-425°C, where the key process parameters were water density (ρw) and HC1 loading.
Abstract: A supercritical water/HCl system was studied for upgrading Paraho shale oil (SO) at 400–425°C. The key process parameters were water density (ρw) and HC1 loading. Increases in ρw increased the selectivity to distillate-range products at the expense of gas and coke products. Increases in ρw also enhanced the ability of HCl to catalyze N-removal. However, coke and gas make also increased with increases in HCl loading. Optimal or “best case” results and conditions were 897% N-removal and 75% distillate yield, at T = 425°C, ρw = 0.2 g/cc, and HCl/SO = 0.05g/g. The underlying chemical mechanisms appeared to involve SCF solvent cage effects and hcterolytic N-removal brought about by dissociation of HCl.
15 citations
TL;DR: An HPLC system was used to separate deasphalted vacuum resids of heavy oils, into saturates, aromatics and two types of resins at preparative scale as discussed by the authors.
Abstract: An HPLC system is used to separate deasphalted vacuum resids of heavy oils, into saturates, aromatics and two types of resins at preparative scale. The separation is achieved using two silica and one cyano bonded silica columns, and cyclopentane, a mixture of chloroform-methanol and dichleramethane as solvents. Automated repetitive injection is required. Recoveries of the sample are around 100%.
14 citations
TL;DR: In this paper, a global kinetic model was developed for the rate of dimethyl ether synthesis in terms of the liquid phase concentration of methanol, and the activation energy of the reaction was found to be 18,830 cal/gmol.
Abstract: The kinetics of the liquid phase catalytic dehydration of methanol to dimethyl ether were investigated. The experiments were carried out under low concentrations of feed in a 1-L stirred autoclave, according to a statistical experimental design. The inert liquid phase used for this investigation was a 78:22 blend of paraffinic and naphthenic mineral oils. A complete thermodynamic analysis was carried out in order to determine the liquid phase concentrations of the dissolved species. A global kinetic model was developed for the rate of dimethyl ether synthesis in terms of the liquid phase concentration of methanol. The activation energy of the reaction was found to be 18,830 cal/gmol. Based on a step-wise linear regression analysis of the kinetic data, the order of the reaction which gave the best fit was 0.28 with respect to methanol. Effects of the solid to liquid and the gas to liquid mass transfer resistances on the kinetic rate have also been investigated.
12 citations
TL;DR: In this paper, the authors show that visbreaking increases the aromaticity (Car) of the residues and decreases their resins/asphaltenes ratio, and a relationship between δCar and resins and resin/as-phoenes ratio has been found, showing that the cracking of aliphatic chains which takes place during the thermal process produces asphalthenes with lower molecular weight and more condensed aromatic structures.
Abstract: The atmospheric residues, the corresponding visbroken residues and the related asphaltenes have been characterized by elemental analysis, liquid and gel permeation chromatography (LC, GPC), nuclear magnetic resonance (NMR) and pyrolysis/gas chromatography/mass spectrometry ( Py/GC/MS) before and after the thermal process. The results show that visbreaking (VB) increases the aromaticity (Car) of the residues and decreases their resins/ asphaltenes ratio. A relationship between δCar and resins/as-phaltenes ratio has been found. The cracking of aliphatic chains which takes place during the thermal process produces asphalthenes with lower molecular weight and more condensed aromatic structures. The rise up to 60% of the ratio of aromatic to paraffinic carbon (Car/Cp ( greatly affects the solubility of VB asphaltenes in a oily medium.
12 citations
TL;DR: In this paper, a coal tar cut (100-230°C) obtained from a Gasifier Plant operating with “Mina do Leau” high-ash coal was fractionated into ABN “acid-base-neutral” groups.
Abstract: Brazilian coal tar oil has been characterized by combined spectroscopic and chromatographic methods. A coal tar cut (100-230°C) obtained from a Gasifier Plant operating with “Mina do Leau” high-ash coal was fractionated into ABN “acid-base-neutral”groups. Infrared spectra and elemental analysis of each fraction has demonstrated the success of the fractionation step. GC/MS analysis of the total cut before the ABN fractionation revealed only hydrocarbons present in the sample. However, after the pre-fractionation step several nitrogen containing compounds of environmental concern were positively identified by GC/MS in the tar bases fraction.
10 citations
TL;DR: In this article, two coal tar cuts, A (boiling range 100°C -230°C) and B (baking range 230°C-300°C), obtained by distillation of Mina do Leao coal tar oil, are compared after the isolation of bases by both methods through elemental analysis, infra-red spectroscopy and mass yield.
Abstract: Selective isolation of coal tar bases was performed by using two different separation methods: liquid-liquid extraction (LLE) and column liquid chromatography (CLC). Two cuts, A (boiling range 100°C – 230°C) and B (boiling range 230°C – 300°C), obtained by distillation of “Mina do Leao” coal tar oil, are compared after the isolation of bases by both methods through elemental analysis, infra-red spectroscopy and mass yield. In addition, cut A and its bases generated by both LLE and CLC were investigated by GC/MS. Pyridines, quinolines and anilines are the major classes found in the base fractions obtained by both methods. Although both showed to be equally selective for base isolation, the column liquid chromatography method demonstrated better recovery.
TL;DR: In this paper, a substantial amount of strongly bound organic matter (SOM) can be separated from oil sands feed and sludge solids, after removal of bitumen by toluene, using a supercritical fluid extraction (SFE) method.
Abstract: The presence of strongly bound organic matter (SOM), in association with certain solids fractions, causes serious problems in the processability of Athabasca oil sands as well as in the settling and compaction of Hot Water Process tailings pond sludge. It has been demonstrated that a substantial amount of this SOM can be separated from oil sands feed and sludge solids, after removal of bitumen by toluene, using a supercritical fluid extraction (SFE) method. The extracted material is soluble in common organic solvents which allows a direct comparison, between the SOM separated from oil sands and sludges, from the point of view of both gross analysis of the major compound types and detailed analysis of chemical structures.
TL;DR: In the x-ray diffraction of carbonaceous materials, there is no logical reason to assume an interrelation between the intensity of the (002) peak, reflecting intermolecular stacking order of aromatic planes, and the fractional aromaticity measured by carbon nuclear magnetic resonance.
Abstract: In the x-ray diffraction of carbonaceous materials, there is no logical reason to assume an interrelation between the intensity of the (002) peak, reflecting intermolecular “stacking” order of aromatic planes, and the fractional aromaticity fa measured by carbon nuclear magnetic resonance. Approaches to the calculation of a diffraction-based aromaticity f002 by comparing the intensity of the (002) peak to that of the γ-band at 450 pm, reflecting intermolecular order of saturated chain hydrocarbons, are fundamentally flawed. The use of diffraction linewidth data for peaks near 210 pm (“(100)”) and near 120 pm (“(110)”) to infer an aromatic diameter has difficulties in systems containing hydroaromatic molecules (e.g., tetralin) because the naphthenic moiety contributes to diffraction peaks in the 210 and 120 pm regions.
TL;DR: In this paper, the solubilization and desulphurization of Beypazari lignite with supercritical ethyl alcohol/NaOH was investigated, and the average molecular weights obtained in experiments with ethylalcohol/coal ratios of 3,6 and 20 were 430,450 and 465, respectively.
Abstract: The solubilization and desulphurization of Beypazari lignite with supercritical ethyl alcohol/NaOH was investigated. Supercritical experiments of 60 minutes were done in microreactors of 15 ml at 245°C by changing the ethyl alcohol/coal ratio from 3 to 20 under a nitrogen atmosphere. As the ethyl alcohol/coal ratio was increased the yield of solubilization and desulphurization also increased. Higher yields of extraction in the case of ethyl alcohol/NaOH experiments may be due to the fact that alcohols can transfer hydrogen more easily in the presence of bases. The average molecular weights of liquid products obtained in experiments with ethylalcohol/coal ratios of 3,6 and 20 were 430,450 and 465, respectively. In experiments with ethylalcohol/NaOH system as the ethylalcohol/coal ratio was increased from 3 to 20 the sulphur content of the coal decreased to 0·75%. In experiments with greater ethylalcohol/coal ratios mercaptane type sulphur chemicals have been extracted,disulphides were missing in t...
TL;DR: In this paper, the number average molecular weights (MW) of Utah bitumens were extracted by gel permeation chromatography (OPC) and the results were compared with those for the corresponding fractions separated from Athabasca maltenes.
Abstract: Maltenes derived from Utah bitumens were separated by gel permeation chromatography ( OPC) into fractions having number average molecular weights ( MW) in the range from 300 to 11985. The fractions were examined by vapor pressure osmometry, absorption spectrometry in the visible region as well as proton and carbon -13 NMR. The results are reported in comparison with those for the corresponding fractions separated from Athabasca maltenes. Utah fractions appeared to be more aliphatic with longer average aliphatic chains lengths. Branched and alicyciic types were more abundant in Utah samples, especially those with low MW, There was an apparent difference in the hydrocarbon structure of both Utah and Athabasca maltenes GPC
TL;DR: In this paper, a method was developed to effect the separation of Fischer-Tropsch products, predominately hydrocarbons, into, first, alkane and alkene fractions, and, secondly, each of these fractions into their normal and branched components.
Abstract: A method has been developed to effect the separation of Fischer-Tropsch products, predominately hydrocarbons, into, first, alkane and alkene fractions, and, secondly, each of these fractions into their normal and branched components. Conditions for methods using a “dry” silica column for the first separation and molecular sieves for the second separation have identified that permit collection of sufficiently large samples for subsequent separations. The first separation has been effected so the normal to branched chain ratio has not been altered. Liquid chromatographic conditions have been found whereby the n-alkane fraction can then be separated to provide a pure sample of each alkane in the C8 - C24 carbon number range. The alkane fractions have been collected so that the 14C activity can be determined for each alkane.
TL;DR: In this article, the effect of the mineral matrix on the recovery of organic material by supercritical toluene extraction from Turkish Goynuk oil shale was investigated, where the inorganic matrix of the shale was composed of calcite, silicate and pyrite minerals.
Abstract: Effect of the mineral matrix on the recovery of organic material by supercritical toluene extraction from Turkish Goynuk oil shale was investigated. Samples were prepared by successive demineralization procedures to study the interaction of different mineral groups during the supercritical interaction. Extraction experiments were done in a stainless steel autoclave of 75 ml capacity at 350°C for 60 minutes. Effect of the toluene/kerogon ratio and reaction time on the recovery of organic material was studied. Infrared spectra of the spent material uere measured to determine the structure of the organic material remaining after the supercritical treatment. The inorganic matrix of the shale was composed of calcite, silicate and pyrite minerals. Recovery of the organic material in the supercritical extraction experiments increased from 42% to 98% as the toluene/kerogen ratio was increased from 23.5 to 275. The extent of depolymerization seemed to be dependent on the to!uene/kerogen ratio and this sug...
TL;DR: In this paper, the chemistry of resid upgrading was studied by following the changes caused by hydrotreatment of Hondo 450°F+ resid, its separated asphaltenes and maltenes, and polar, aromatic, and saturate fractions.
Abstract: The chemistry of resid upgrading was studied by following the changes caused by hydrotreatment of Hondo 450°F+ resid, its separated asphaltenes and maltenes, and polar, aromatic, and saturate fractions. Both continuous and batch hydrogenations were studied, using two commercial resid hydrotreating catalysts. At low reactor temperatures, the most important reactions are saturation of aromatics and removal of reactive heteroatoms. Increasing the temperature adds cracking reactions. Detailed results can he explained by arbitrarily assigning to resid cuts the ranking: saturates > aromatics > polar compounds > asphaltenes and assuming that hydrotreating moves materials upward in the hierarchy. Each cut can form products only at or above its ranking. Only asphaltenes can give rise to asphaltenes in the products. Asphaltenes are the most difficult resid fraction to treat, and they reduce the catalyst's activity for treating other fractions, possibly by blocking pores or adsorbing strongly on the catalys...
TL;DR: In this paper, an experimental study has been carried out on hydrocarbon group analysis of commercial Arabian crude oil fractions corresponding to the true boiling point ranges or 200-400 ast;F, 400-500 ∗F, 500-650 ∗ F, 650-850 ∗-K, and 850-F-K.
Abstract: Experimental studies have been carried out on hydrocarbon group analysis of commercial Arabian crude oil fractions corresponding to the true boiling point ranges or 200–400 ast;F, 400–500 ∗F 500–650 ∗F, 650–850 ∗F, and 850 ∗F-K The crude oils included Arab heavy (API∗ = 28·0), Arab medium (API∗ = 30·0), Arab light (API∗ = 33·3), and Arab Berry extra light (API∗ = 36∗9). Waters Hydrocabon Group Analyzer (HGA) system interfaced with model 730 Data Module has been used to obtain the compositional analysis in terms of saturates, neutral aromatics, polar aromatics and asphaltcnes.
TL;DR: In this article, a method was developed whereby the viscosity of a tar sand bitumen at any temperature can be calculated from nuclear magnetic resonance parameters, based upon some fundamental theoretical concepts for molecular mobility and intermolecular interactions.
Abstract: Many physicochemical properties of bitumens must be known in order to mathematically model and simulate the processes used for the recovery of bitumen from tar sands. One fundamental property is the temperature dependence of viscosity. This property determines the heat transfer and flow characteristics of a bitumen through a porous media. A method has been developed whereby the viscosity of a tar sand bitumen at any temperature can be calculated from nuclear magnetic resonance parameters. The method is semiempirical but is based upon some fundamental theoretical concepts for molecular mobility and intermolecular interactions. Using this method, the viscosities of three United States tar sand bitumens have been correlated to the weighted average spin-spin relaxation rates for the semiliquid, solidlike mobile, and solidlike rigid phases of the bitumens. The results indicate that bitumens with a high viscosity have a greater amount of solidlike rigid phase and lesser amounts of solidlike mobile and ...
TL;DR: In this paper, hydrogen was incorporated in capping fragments formed during cracking reactions, as well as in hydrogenation reactions, heteroatom removal, and hydrocarbon gas formation, but the distribution of the hydrogen was dependent upon the type and severity of the process.
Abstract: Maya 650{sup 0}F residuum (Maya AR) was prehydrogenated over a standard hydroprocessing catalyst. The 650{sup 0}F residuum of this product (HMaya AR) and Maya AR were then separately hydroprocessed further at selected conditions. The products were examined by elemental, {sup 1}H and {sup 13}C NMR analyses to determine the how hydrogen was incorporated during processing. For all processing steps, hydrogen was incorporated in capping fragments formed during cracking reactions, as well as in hydrogenation reactions, heteroatom removal, and hydrocarbon gas formation, but the distribution of the hydrogen was dependent upon the type and severity of the process. For the direct hydroconversion of Maya AR, 25 to 30% of the total hydrogen was incorporated for heteroatom removal and hydrocarbon gas formation. The remaining hydrogen was incorporated in hydrogenation and cracking reactions. The hydrogen incorporation during each specific processing step is discussed, along with an evaluation of the prehydrogenation step as a residuum conversion process option. These results are compared to previously reported hydrogen incorporation measurements on other feeds and processing methods.
TL;DR: In this article, the effect of precoating antistripping agents onto silica on the adsorption behavior of model asphalt functionalities has been examined, and two commercially available polyamine AS agents were used.
Abstract: The effect of precoating antistripping (AS) agents onto silica on the adsorption behavior of model asphalt functionalities has been examined. Two commercially available polyamine AS agents were used. Their adsorption onto silica showed a strong surface interaction. One of the AS agents followed the Langmuir adsorption model; the other did not. After removing the weakly adsorbed AS fraction by washing with dichloromethane, seven asphalt functionalities In cyclohexane solution were adsorbed onto the precoated silica. The functionalities used represented those present in asphalt and were carboxylic acids, phenolics, nitrogen bases, sulfoxides, ketones, esters, and polynuclear aromatics. The adsorption of benzoic acid and phenol was increased by precoating with AS agents, whereas the other functionalities showed large decreases in their adsorption due to the precoated AS agents. The enhanced adsorption shown by benzoic acid and phenol is likely due to an acid-base interaction between the basic AS age...
TL;DR: In this article, the reaction of Beypazari lignite with ethyl alcohol/NaOH was carried out using a microreactor of 15 ml capacity, which was developed to examine the reaction kinetics of coal extraction and desulphurization under supercritical conditions.
Abstract: The reaction of Beypazari lignite with ethyl alcohol/NaOH was carried out using a microreactor of 15 ml capacity. The microreactors were developed to examine the reaction kinetics of coal extraction and desulphurization under supercritical conditions. The experimental temperature in the microreactor was adjusted to 245°C, 275°C and 295°C. The duration of the experiments was changed between 0 to 90 minutes. The solubilization of Beypazari lignite increased sharply from 15% to 50% within 30 minutes after the temperature reached to 245°C and gradually decreased from 50% to 48% in 90 minutes. The total sulphur (pyritic and organic) content of the acid washed lignite decreased from 3.78% to 2.50% in the first 10 minutes and insignificant changes were observed at longer durations. The percentage of the pyritic sulphur remained constant at about 0.25% throughout the experiments. As the temperature was increased from 245°C to 295°C the time for steady state decreased from 32 minutes to 21 minutes. Solubi...
TL;DR: In this article, the effects of basic calcium sulfonate additives, starting with used oil l000Km, 2000km, 3000km service, vacuum distillates of used oils and base oil, were studied.
Abstract: Infrared absorptions of TLC subtractions of used motor oil, original oil, base oil and the additive, indicate the transformation of the polar and nonpolar components by further oxidation and oxidative degradation of carbonyl compounds into acids, esters and peroxides. Organic nitrates and nitro compounds were also detected after 2000Km and 3000Km service. The effects of basic calcium sulfonate additives, starting with used oil l000Km, 2000Km, 3000Km service, vacuum distillates of used oils and base oil, were studied. It has been found that the dispersant properties of these sulfonates are profoundly influenced by their structure. The alkalinity of the calcium sulfonate additive was determined by spectroscopic-IR method.
TL;DR: In this paper, the germanium content of lignite is directly determined using a solid Lignite sample using a standard solution of Ge was added to powdered coal samples which were then dried.
Abstract: The germanium content of lignite is directly determined using a solid lignite sample. A standard solution of Ge was added to powdered coal samples which were then dried. A simple metallic bar with a cavity in it was used to introduce the sample into the furnace. Optimum temperature programming was determined to obtain Ge signals as free as possible from matrix interferences. Under optimum conditions 1 ng of Ge could be determined in a solid sample. The sensitivity of Ge as (Absorbancs/g Ge) was about 500 times greater in solid sample analysis then in liquid sample analysis.
TL;DR: In this article, the DTA studies in air are reported on some Indian coals and a lignite and they found that extraction of coal in quinoline or in liquid paraffin was found to result in the coal residues having higher ignition temperature than that of the original coal.
Abstract: The DTA studies in air are reported on some Indian coals and a lignite. Extraction of coal in quinoline or in liquid paraffin was found to result in the coal residues having higher ignition temperature than that of the original coal. However, extraction of coal in anthracene oil or successive extractive disintegration of coal in anthracene oil, in quinoline and in liquid paraffin was found to yield residual coals having higher reactivities towards oxygen in air as understood from the fact that the ignition temperature of these residues was lower than that of the original coal. DTA studies also supported the degradation of coal as a result of acidic depolymerization reaction.
TL;DR: In this paper, physicochemical and compositional data of short-path distillation (SPD) and supercritical fluid extraction (SFE) procedures were employed to obtain portions of a short residue (500°C+).
Abstract: Short-path distillation (SPD) and supercritical fluid extraction (SFE) procedures were employed to obtain portions of a short residue (500°C+). The physicochemical and compositional data of SF extract and SP distillates at four wall temperatures were obtained employing various analytical techniques such as vapour pressure osmometry, simulated distillation, infrared and mass spectrometry. The comparison of these data reveals that although the yield of SF extract is small under the present experimental conditions, it contains relatively higher concentrations of paraffins and alkylbenzenes as compared to SP distillates. The hydro carbon type distribution of distillates was found to be the same, independent of the wall temperature used. The comparison of overall composition of SF extract and SP distillates depicts that former is more suitable to be used as lube stocks.
TL;DR: In this paper, the structural changes occurred in Beypazari lignite while oxidizing at 150°C in a dynamic air atmosphere, and the least squares curve fitting techniques were used to resolve the overlapping bands in the 0-220 ppm region of the 13c NMR spectra.
Abstract: The solid state 13C NMR method have been used to investigate the structural changes occurred in Beypazari lignite while oxidizing at 150°C in a dynamic air atmosphere. Least squares curve fitting techniques have been used to resolve the overlapping bands in the 0-220 ppm region of the 13c NMR spectra. Measurements of the relative intensities of the functional groups observed in the oxidized coals were used to follow the progress of air oxidation. Oxidation reactions seemed to decrease the total intensities of both aliphatics and aromatics, though the reduction in aliphatics was more pronounced. The relative intensities of the total aliphatics decreased from 1.0 to 0.9 and 0.6 in the original and lignites oxidized for 12 and 312 hours, respectively. The relative intensities of Ar-C-C in the 130-148 ppm region for the same set of samples were 1.0, 0.9 and 0.8. The least-squares bands resolved in the carbonyl region were at 175 ppm and 190 ppm in the original lignite; at 180 ppm (carboxylic acids), ...
TL;DR: In this paper, a condensed aromatic quinone, 9,10-anthraquinone, was selected as representative of complex quinones, which can be determined in the presence of other oxygen functional groups, alcohols, carboxylic acids, ethers, and other carbonyls.
Abstract: Asphaltenes are a chemically complex mixture of aromatic and heteroaromatic compounds. This material contains oxygen in various functional groups. The distribution includes esters, carboxylic acids, phenolic and most probably quinone type oxygen functionalities. The present work details the complete electrochemical behaviour of quinone type oxygen. The method is quinone specific. A condensed aromatic quinone, 9,10-anthraquinone, was selected as representative of complex quinones. By this method quinones can be determined in the presence of other oxygen functional groups, alcohols, carboxylic acids, ethers, and other carbonyls.
TL;DR: In this paper, an electrochemical method was developed for the characterization of sulphur compounds in coal extracts using Beypazan lignite, which was carried out using a microreactor of 15 ml capacity.
Abstract: The overall objective, of this study is to develop an electrochemical method, that will be complementary to the existing spectroscopic methods, for the characterization of sulphur compounds in coal extracts. Beypazan lignite was used in this study. Supercritical interaction between coal and ethyl alcohol/NaOH (or Ca(OH2) ) was carried out using a microreactor of 15 ml capacity. Liquid products obtained were separated by liquid chromatography in a glass column have been determined and these provided a ground for the identification of various sulphur functional groups in coal liquids obtained from supercritical interaction between a lignite and ethyl alcohol/NaOH or ethyl alcohol/Ca(OH) 2 or ethyl alcohol. Organic sulphur compounds determined by this method were dibenzydisulphide, dibenzothiophene and tiophenol