Masaaki Satou

An h.p.l.e. and m.s. analysis of distillate fractions of neutral oil from hydrogenated Akabira coal to elucidate chemical structures

Abstract Akabira coal-derived neutral oil was separated into 25 narrow boiling range fractions covering 183–423 °C, and subsequently separated into compound class fractions : alkanes, monoaromatics, naphthalene-type diaromatics, fluorene-type diaromatics and tri- and/or tetraaromatics, by high performance liquid chromatography (h.p.l.c.). The compound type analyses of the distillate/h.p.l.c. fractions were performed using electron impact mass spectroscopy (e.i.m.s.) or field ionization mass spectroscopy (f.i.m.s.). Aromatic/hydroaromatic compound types and the alkyl side-chain carbon distribution of the distillate/h.p.l.c. fractions were clarified, based on the separation behaviour of h.p.l.c. and the type analyses according to Z value by m.s. By the distillation/h.p.l.c./m.s. method, coal-derived oil was characterized in terms of the distribution of the numbers of aromatic rings, naphthenic rings and carbons of alkyl groups attached to these rings. The variations in chemical structure in a compound class with distillation temperature are discussed in terms of these chemical structural factors.

Contributions of aromatic conjunction and aromatic inner carbons to molar volume of polyaromatic hydrocarbons

A modification of our previous equation for estimation of the molar volume of hydrocarbons on the basis of atomic group contributions was made to be able to extend the applicability to a wide variety of hydrocarbons, including condensed polyaromatic hydrocarbons (CPAHC), which are main components in heavy oils. Two atomic groups were additionally selected to characterize CPAHC, namely aromatic conjunction (ac) and aromatic inner (ai) carbons. Utilizing the molar volume data for pure CPAHC in literature, increments in the molar volume by the presence of the two groups were evaluated by a regression analysis as 2.8 and 8.6 ml/mol, respectively. The molar volumes of hydrocarbon mixtures in heavy oils containing CPAHC, estimated with the above increments, agree well with those observed. The equation is applicable to polyaromatic hydrocarbons with the ring numbers up to seven in both forms of pure substances and their mixtures.

Evaluation of ring size distribution in a heavy oil based on boiling point and molecular weight distributions

Abstract To establish a rapid and versatile method for estimating structural distributions of compositions in heavy oils, an aromatic ring size distribution is evaluated from a boiling point distribution obtained by a simulated distillation on the basis of our relationship between boiling points and chemical structures for heavy oils. To obtain the boiling point distribution, two simulated distillations for heavy oils were examined. One is a chromatographic method with a conventional GC or a supercritical fluid chromatography(SFC). The other is based on our boiling point calculation, which is related with chemical structures of heavy oils. Similarity of both simulated distillation curves suggests that the simulated distillation of the heavy oil by SFC could be available for a characterization of the heavy oil including non-volatile materials. An evaluation method for a ring size distribution is proposed based on the boiling point distribution obtained from the simulated distillations. There was a difference between an actual boiling point distribution of the heavy oil and an imaginary one calculated on the assumption that all of the components were straight alkanes. The temperature difference (ΔT) between both distributions at the same distillate content is attributed to non-paraffinic structures in the heavy oil. As compared the aromatic ring size distribution evaluated by the temperature difference with the distribution analyzed by HPLC–MS measurement, both aromatic size distributions were in good agreement each other.

Structural analysis and estimation of boiling point of hydrocarbons in a coal-derived liquid by a group contribution method

Abstract The relationship between chemical structure and boiling point of hydrocarbons in a heavy oil has been proposed based upon systematic structural analyses using high performance liquid chromatography (h.p.l.c.) and gas chromatography-mass spectroscopy (g.c.-m.s.). The boiling point of a compound in a coal-derived liquid was converted from the retention time in g.c.-m.s. by calibration using a series of aromatic hydrocarbon standards. The chemical structures of the aromatic hydrocarbon compound types are characterized by five atomic groups: numbers of total carbons, aromatic rings, naphthenic rings, aromatic conjunction carbons and aromatic inner carbons. At a total carbon number in a given compound, the group contributions to the boiling point, rendered as deviations from the boiling point of an n-paraffin with the same carbon number, were determined by regression analysis. They are as follows: 29.7 K per aromatic ring, 10.4 K per naphthenic ring, 1.7 K per aromatic conjunction carbon and −4.6 K per aromatic inner carbon. A simple equation for calculating boiling points of hydrocarbons is proposed, which requires only chemical structure information.

Distribution in coal-derived oil of aromatic hydrocarbon compound types grouped according to boiling point by high performance liquid chromatography-gas chromatography/mass spectrometry

Abstract Yubarishinko coal-derived neutral oil was separated into compound class fractions, alkanes (Fr-P), monoaromatics (Fr-M), diaromatics (Fr-D) and tri- and/or tetra-aromatics (Fr-T), by high performance liquid chromatography (h.p.l.c.). The compound type analyses of aromatic compound class fractions were performed using a gas chromatograph/mass spectrometer. Based on h.p.l.c. separation behaviour and the compound type analyses according to Z number by mass spectroscopy (m.s.), aromatic fractions in a neutral oil were characterized in terms of three chemical structural parameters: the number of aromatic rings; the number of naphthenic rings; and the number of alkyl side chain carbons attached to these rings. Converting gas chromatography (g.c.) retention time into boiling point, the boiling point distributions of aromatic hydrocarbon compound types were clarified and the variations in chemical structure with boiling point are discussed in terms of their chemical structural parameters.

Correlation of chemical constitution and boiling point with separation behaviour during distillation of coal liquid

Abstract The separation behaviour of coal hydrogenation liquids during distillation was clarified using correlations between chemical structural factors (R a , R n and C al ) and boiling points of narrow cut distillation fractions. The separation order according to chemical structure at given distillation temperatures was represented on a three-dimensional R a R n C al diagram. In this diagram, one axis represents the number of aromatic rings in the structure of a compound (R a ), one represents the number of naphthenic rings (R n ), and the third axis represents the number of alkyl carbons (C al ). This diagram is believed to be an appropriate way to handle the analysis of molecules in coal liquids, which are extremely complicated mixtures. Kerosene, light oil and heavy oil from coal liquid were also characterized on this diagram. The distribution ranges of components during separation in distillation agree fairly well with their corresponding distillation temperature range on the R a  R n C al diagram proposed. The distillation curve was predicted from the structural analyses with h.p.l.c./g.c.-m.s. and constitution-boiling point correlation as shown in the R a R n C al diagram.

Distribution of aromatic hydrocarbon compound types grouped according to boiling point in neutral oils derived from various coals

Abstract Five coals were hydrogenated at 673 K for 60 min under an initial hydrogen pressure of 10 MPa with Adkins catalyst. The distributions of boiling points of hydrocarbon compound types were obtained by h.p.l.c. coupled with g.c.-m.s. The boiling-point diagrams obtained provide accurate estimates of the number of aromatic rings, naphthenic rings and alkyl side-chain carbons in a group of fractions which boil in a given range of temperatures. Compound types of low Z numbers show greater variation in boiling-point distribution with coal carbon content than those of high Z numbers in fractions Fr-D and Fr-T. The higher the carbon content of the coal, the greater the incidence of compound types of low Z number with high boiling points in Fr-D and Fr-T. Consequently the distillation curves of these compound classes derived from a high-rank coal rise faster with boiling point than those for a low-rank coal. At a given boiling point, the average carbon number of alkyl side chains for each compound type is almost constant, regardless of the carbon content of the coal. That is, in a limited range of boiling points, compound types with the same carbon number are derived even if the coals have different carbon contents.

Vapor pressure estimation for hydrocarbons in a coal derived liquid

Publisher Summary This chapter discusses the vapor pressure estimation for hydrocarbons in a coal-derived liquid. The vapor pressure is one of the fundamental properties for process design and control. In spite of numerous studies on vapor pressure estimation for pure organic compounds, their applicability to coal derived liquids is not confirmed yet. The difference (δ log P) of logarithmic values of the vapor pressure of hydrocarbon homologue with straight alkanes having the same total carbons is invariable at a given temperature with the total carbon number. The value of δ log P is found to be inversely proportional to the reciprocal of temperature with the slope gradually becoming steep with the numbers of aromatic and naphthenic rings. A simple equation is proposed based on these findings.

The distribution of compound classes in coal-derived oil by HPLC-FID method.

The distributions of compound classes in coal-derived oil were investigated by high performance liquid chromatography (HPLC) and thin layer chromatography equipped with a flame ionization detector (TLC/FID).Neutral oils, free of the acidic and the basic portion, were separated into 5 compound classes Fr-P (alkanes), Fr-M (monoaromatics), Fr-D (diaromatics), Fr-T (tri-or tetraaromatics) and Fr-PP (polyaromatics or hetero compounds). Separations were performed by HPLC using a Zorbax BP-NH2 column, as reported previously. Quantitative distributions of these compound classes were estimated by FID, compared with the conventional gravimetric method.In order to accurately determine the contents of compound classes, it is necessary to examine the sensitivity of FID response. The sensitivities of FID for compound classes with a larger number of aromatic rings, such as Fr-T and Fr-PP, were higher than those of compound classes with smaller number of aromatic rings, such as Fr-P, Fr-M and Fr-D. The contents were estimated by using the calibration curves, which give the relationhips between contents and signal intensities of FID (TLC peak area in this case) for each compound class. Consequently, distributions of compound classes with parent coal C% by FID agrees fairly well with those according to the gravimetric method.It is concluded that the HPLC-FID method is useful for characterization of coal-derived neutral oil. So, routine quantitative analyses can be carried out relatively easily by this method.

The composition changes of recycle solvents on the coal liquefaction. II On the polar compounds by HPLC-GC/MS method.

The composition changes of polar compounds in recycle solvents (S-1-6) derived from liquefaction experiment with Akabira coal are examined by means of HPLCGC/MS method.Using HPLC equipped with a Zorbax BP-NH2 column, polar compounds in recycle solvents were separated into three polar compound classes (Fr-B, N and A) in a stepwise elution system with different concentrations of solvents from hexane to chloroform.Major polar compound classes in hydrogenated anthracene oil (HAO), used as a starting solvent, were Fr-B (basic nitrogen compounds) and N (neutral hetero compounds), and were mainly composed of carbazoles, benzoquinolines and azapyrenes. However, very little Fr-A (acidic oxygen compounds) was contained in HAO.The amounts of Fr-N and of carbazoles in S-1 increased more than they did in HAO. But after the first recycle, their levels remained approximately constant regardless of recycling. The levels of anilines and indoles, little contained in HAO, increase with recycling. That is, nitrogen compounds with high molecular weight, such as carbazoles and benzoquinolines derived from coal were partially hydrogenated and cleavaged. Then, nitrogen compounds with low molecular weight, such as anilines and indoles, were produced and their levels increased with recycling.Fr-A accumulated in the recycle solvent in each recycle and was mainly composed of phenols, phenylphenols and indanols/tetrahydronaphthols.In general, the level of compounds with low-carbon number of alkyl side chains increased with recycling. This means that the reaction of dealkylation occurs in coal liquefaction.