According to A. S. T. M. D 2977-9, it is impossible to do maceral analysis of such fine coal as-200mesh 100 Percent. However, sometimes the maceral analysis of such fine coal should be done for example in the case of the transportation of slurried coal and Pelletizing of fine coal. For these reasons, the analytical method of coal petrography of such very fine coal was established by the application of high pressure (8, 000 psi) in the molding stage.
At the same time, it was found that the molding pressure affected the result of maceral analysis considerably.
It is mainly due to the malleability of soft components that soft components i. e., vitri-nite, exinite are overestimated in the application of high molding pressure.
As the index of the degree of anisotropy, (1-R_min/R_max.) ×100 would be proposed because of its superiority compared with bireflectance (R_max-_Rmin).
Also, it was verified that (1-R_min/R_max) ×100 was quite useful to detect the effect of carbonization conditions (heating rate, soaking time, maximum treating temp.) and Oxidation degree of coal, to the coke texture. The determination of the inerticity of low reflectance semifusinite which had been reported as quite unique maceral to be found especially in Western Canadian coal was tried.

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Changes in micropore structures of six Japanese coals with heat treatment up to 1200°C were followed by measuring densities in n-hexane, in methanol and in helium. Micropore volume was deduced from the difference detween the reciprocals of density in n-hexane and in methanol. The concept of the “crystallite” was used in discussion for the micropore structures of carbonized coals. The different variation in micropore structure with heat treatment between lower rank coals and higher rank coals could well be elucidated by classifying the lower rank coals and the higher rank coals to non-graphitizing carbon and graphitizing carbon respectively.
It was suggested that the entrance diameters of the micropores located among the crystallites are smaller than the diameter of n-hexane molecules for coals and their carbonized products.
The density in methanol was larger than that in helium for all the carbonized coalsheat treated up to 700-800°C. It was shown that the excess of density in methanol over that in helium closely relates to the mean average number of the layers in a crystallite obtained from the X ray measurement.

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The present investigation was undertaken to know the effect of chemical structure of pitches and quinoline insoluble on the formation and the growth of spherical bodies observed in the early stage of carbonization of pitches. Naphtha pitch and coal tar pitch were used as samples, and were fractionated by n-hexane, acetone, benzene and quinoline into four fractions No.1, No.2, No.3 and No.4, respectively. And then, each fraction was carbonized to examine by polarized-light microscope.
Then, the structural parameters for each fraction of naphtha pitch and coal tar pitch were estimated from hydrogen distribution determined by NMR spectra, elemental analyses and molecular weight. It has been found that the aromaticity of naphtha pitch was lower than coal tar pitch, and the number of side-chains in naphtha pitch was high value compared with coal tar pitch. Furthermore, the average number of condesed aromatic rings of each fraction had a tendency to increase in the order No.1 to No.3 in both naphtha pitch and coal tar pitch.
Although the formation and the growth of spherical bodies in fractions of both naphtha pitch and coal tar pitch were easy in the order No.3 to No.1, the formation and the growth of spherical bodies in naphtha pitch were easy compared with coal tar pitch. For example, the formation of spherical bodies in the fraction No.3 of naphtha pitch was observed at the condition of 400°C and 2 hr, but that of coal tar pitch at 420°C and 2 hr.
It is interesting that the fraction No.4, that is, quinoline soluble-benzene insoluble fraction, did not fused even at 600°C and 2hr. From above result, one might have concluded that it was necessary, in the formation and the growth of spherical bodies, that pitch had a suitable size of condensed aromatic rings and some side-chains with the rings.
Further investigation was carried out for the purpose to clarify the effect of the quinoline insoluble on the formation and the growth of spherical bodies. When a small amount (less than 1%) of the quinoline insoluble was mixed into the fraction No.3 of coal tar pitch, no effect was observed in the formation and the growth. But, when in excess (more than 5%), it interfered them.

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In order to elucidate the mechanism of free spin formation in the early stage of coalification, 14 kinds of brown coals originated from Yallourn seam and Morwell No.1 seam at Latrobe Valley, Victoria, Australia were examined in their ESR characters. That is, spin concentration, g-value, line width and saturation effect were observed by use of a X-band ESR spectrometer. The results were compared with those obtained on artificial coals, previously examined by the present authors, and with those of several kinds of wood debris whose origin is known on the basis of geological, archaeological or historical standpoints. It was concluded that not only geological thermal and/or time effect but also biological degradating effect was controlling the ESR characters of the materials found in the early stage of coalification.

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Regenerated humic acids (HA I) prepared by nitric acid oxidation of four kinds of coals (C: 75.7-87.1%) were fractionated on Sephadex G-75 gel with 0.75N NaOH solution and the elution curve and IR spectral data of the fractions obtained were examined in comparison with those of the other humic acids prepared by the other methods or from lignite.The elution curves showed two peaks at higher and lower molecular weight parts and that of higher molecular weight part increased its hight with the increase of the carbon content of raw coal. While the measure of aliphatic hydrocarbon contents obtained from IR spectral dota was high at higher molecular weight part and steeply decreased to low value with the decrease in molecular weight, that of carboxyl group contents increased with the decrease in molecular weight and with advancing the oxidation. Regenerated humic acid (HA II and III) prepared by air oxidation and by alkali fusion, natural humic acid (HA IV) and regenerated humic acid (HA V) prepared by nitric acid oxidation of lignite were also fractionated. HA II showed similar elution curves to HA I. The curve of HA III was specific and rich in high molecular weight part. Those of HA IV, HA V were very similar with each other and rich in low molecular weight part. The fractions from Takamatsu regenerated humic acid prepared by nitric acid oxidation were further studied on their molecular weight, neutralization equivalent weight and ion exchange properties. The weightaverage molecular weight (M_w) of each fraction determined by sedimentation equilibrium method was ranged from 4.103 to 1.105 and decreased reversely with the increase of the elution volume. The molecular weight distribution was calculated from the relation of elution volume/void volume value to log M_w. Neutralization equivalent weight of the fractions decreased with the increase of molecular weight. Adsorption capacity of Cd ion on the fractions in CdCl₂ solution at initial pH 5 was in a range from 1. 37 to 0.88 meq./g and increased with the decrease in molecular weight. A measure of the relative affinity of the adsorption of copper ion was also determined from the adsorption equilibrium data. The value of the lowest molecular weight part was about 340 times that of the highest molecular weight part. The results on the adsorption revealed that the chelating ability was more remarkable in the lower molecular weight parts.

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The chemical constitution of oil produced by Yubari coal hydrogenolysis under high pressure was studied. Hydrogenolysis of Yubari coal was carried out under 200-220kg/cm² hydrogen pressure at 390-410°C for three hours with no vehicle. Oil was obtained in about a 30% yield on the basis of Yubari coal (d. a. f.). The oil was fractionated by three different methods, namely, solvent fractionation, fractionation by adsorption on alumina and gradient elution adsorption chromatography (GEAC).
The average structural parameters of each fraction were estimated by ultimate analysis, IR-and UV-spectra, average molecular weight determination by vapor pressure osmometry and hydrogen distribution by high resolution NMR.
The results on the basis of the structural analysis of each fraction were as follows: -(1) Oil seems to consist of paraffinic, naphthenic acid aromatic constituents.(2) The average molecular weight of fractions ranged from 180 to 1210.(3) The aromaticity (fa) of the fractions showed from 0.00 corresponding to aliphatics only, up to 0. 73.(4) The parameter of condensed aromatic ring (Hau/Ca) of the fractions varied from 0.69 to 1.00 which correspond to a five to one condensed aromatic ring system.(5) The parameter of the length of alkyl side chain (Ho/Hc) was 0.5 to 4.1 corresponding to that of the alkyl side chain which had approximately 2 to 5 carbon atoms.

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The effects of red-mud and sulfur catalyst on the reaction process of coals treated with hydrogen under high pressure and the chemical structure of the resulting reaction products were dicussed on the basis of the changes in the chemical structure of benzene-solubles using high resolution NMR spectroscopy. These were compared against the results obtained when no catalysts were used.
The effects of red-mud and sulfur catalyst on the conversion were recognized in reaction temperatures (over 350°C in Oyubari coal and over 375°C in Taiheiyo coal) after the onset of the plastic state, namely after the reactants entered the liquid phase.
In the initial reaction course of hydrogen treatment under high pressure up to a conversion of 20 wt. % or thereabouts, it may be said that insofar as this process is concerned, regardless of the presence of red-mud and sulfur catalyst, the results are the same as that when no catalyst was used. Namely, up to a conversion of 20 wt. % or thereabouts the portion of the coal substance in which an uneven distribution of aromatic rings is seen in the structural units, can be dealt with thermal reaction resulting in separation and distillation to benzene-solubles. Red-mud and sulfur catalyst has no catalytic action such as hydrogenation in such a process. On the other hand, in the reaction course after 20 wt. % conversion, it may be said that the reaction of the sample coal proceeds through a plastic state on to a liquid phase, and the chemical structure of coal related to this process is comparatively uniform. In this reaction course the presence of red-mud and sulfur catalyst causes cleavage to occur at the mid Portions of the chains rather than at the bridge structures at the end of the chains.

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As a result of studies of reaction kinetics and the characteristics of oil products of Taiheiyo Coal, it was surmised that this particular coal has a unique chemical structure with special behaviors as compared against other Hokkaido Coals. Based on this, mild hydrogenolysis under pressure was conducted, and a follow up of the changes of the proceedings of the reaction products ° structural parameters were made. Based on these results, discusions were made on the reaction mechanisms of high pressure hydrogenolysis of Taiheiyo Coal ° the chemical structure thereof.
In the chemical reaction occuring in the reaction course, it was noted that (1) the cleavage of the linkage between the mean structural unit, (2) the dealkylation of side chains, and also dealkylation in the direction of shortening the length of side chains, (3) the hydrogenation of condensed aromaticrings was small.
It was also noted that in the mean structural unit of the skeletal structure of the main portion of Taiheiyo Coal with regards to condensed aromatic rings was within a degree of two condensed aromatic rings or thereabouts, while the degree of substitutions of aliphatic side chains was around 0.3 and the length of the side chains measured with H₀/H_α was over 1. 4. It was also surmized that the linkage of the structural units was stronger than other Hokkaido Coals. For instance, whereas other Hokkaido Coals show a 2 dimensional linkage it was surmized that Taiheiyo Coal has a 3 dimensional linkage. This hypothesis seems to give a satisfactory explanation for the fact that whereas the reaction rate of Taiheiyo Coal is slow the resulting product oil has, in the majority of cases, a low boiling point.

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