S. Kikkawa

Improved method to alkylate Yūbari coal of Japan using molten potassium under refluxing THF

A modification to Sternbergs procedures of reductive alkylation of coals is proposed. The ‘coal anion’ formation reaction is conducted under refluxing THF without any electron transfer agent and with molten potassium metal. The method was applied to Yūbari coal (86 wt % C) whereby varying reaction times (0.5–6 h) altered the lengths of alkyl groups (CH3C4H9) added. In a typical experiment, a butylated Yubari coal, prepared by the 2 h reaction, contained 7 butyl groups per 100 original carbon atoms and solubility in hot benzene was 75 wt %. The numbers of alkyl groups introduced and the solubilities of coals increased with reaction time. Values obtained were comparable to those reported using conventional procedures which required longer reaction times and an electron transfer agent l.r. spectra of butylated coals showed strong adsorption peaks attributed to aliphatic groups. Benzene-soluble—pentane-insoluble material of the alkylated coal had less condensed aromatic components with more alkyl side-chains compared with Yūbari SRC, which were estimated by the Brown—Ladner method. Contamination of the alkylated coal by THF fragments seems to be negligible, since hydrogenated naphthalene, obtained after treatment with molten potassium, contains no alkylated products. The reaction proceeded also in HMPA, but not in straight-chain hexane.

Hydrogenation of Yūbari coal coated with ZnCl2-MCln (CuCl, CrCl3 and MoCl5) catalyst melts

Abstract Hydrogenation of Yūbari coal coated with 5 wt% of ZnCl 2 -MCl n (CuCl, CrCl 3 and MoCl 5 ) was carried out at 400 °C for 3 h with an initial hydrogen pressure of 9.8 MPa. The binary melt catalysts showed relatively higher activity in increasing the yield of hexane-solubles than did ZnCl 2 alone. The ZnCl 2 -MoCl 5 catalyst melt was best in view of its highest conversion (90.9 wt%), the highest yield of hexane-soluble material (50.5 wt%) and the smallest hydrogen consumption. In terms of yield of monoaromatics of the hexane-soluble material relative to polar materials, ZnCl 2 -CrCl 3 catalyst was superior to ZnCl 2 -MoCl 5 although its hydrogen consumption was high. The roles of CuCl, CrCl 3 and MoCl 5 in association with ZnCl 2 in coal-hydrogenation are discussed.

Comparison of coal hydroliquefaction catalysed by ZnCl2-MCln (CuCl, CrCl3 and MoCl5) and ZnCl2 melts

Abstract Hydrogenation of four bituminous coals impregnated with 5 wt% of either mixtures of ZnCl 2 - M Cl n (CuCl, CrCl 3 and MoCl 5 ) systems or ZnCl 2 was carried out using a batch autoclave system at 400° for 3 h at 9.8 MPa of initial hydrogen pressure. The ZnCl 2 -MoCl 5 system showed the highest yield of the hexane-soluble (HS) fraction compared with the other systems irrespective of the coal used. The difference between the yields of HS fractions using the ZnCl 2 -MoCl 5 and other systems was most marked for coals of fairly low volatile matter content, though the conversion was relatively low (47–66%), whilst for coals of high volatile matter content HS yields with the binary melt systems were high (86–91% conversion). Elemental analyses of the HS fractions indicated that the ZnCl 2 -MoCl 5 system is most favourable in decreasing the average molecular weight and the heteroatom content of HS, this characteristic trend being confirmed also with five HS fractions separated by Chromatographic techniques. Both elemental analyses and molecular weights of asphaltene (benzene-soluble materials, BS) indicated that the ZnCl 2 -MoCl 5 system is also most effective in cracking coal structure.

Hydrogenation of Japanese coals catalysed by metal halides

Abstract The hydrogenation of Yubari coal impregnated with Znl 2 was carried out at 400 °C for 3 h in a batch autoclave system. The conversion exceeded 83% of daf coal when Znl 2 was used at 1 wt % of dry coal. The yield and the average molecular weight of asphaltene showed maxima at 1 wt % Znl 2 . Longer reaction times brought higher yields of gases and oil and a lower yield of asphaltene; however, extremely long reaction time caused recombination of asphaltene fragments. A binary mixture of metal halides, ZnX 2 /CuX, showed higher activity than ZnX 2 . The hydrogenation of other Japanese coals was studied for comparison with that of Yubari coal under the same conditions.

Effects of petrographic constituents in three Yallourn brown coal lithotypes on hydroliquefaction processes

Abstract Pale, medium-light and medium-dark lithotypes of Yallourn coal were hydrogenated with and without ZnCl 2 -containing catalysts (400 °C, 9.8 MPa H 2 and 3 h). The degree of hydroliquefaction was examined petrographically. Without catalyst, the amounts of water produced can be correlated with the amounts of humodetrinite; whereas with catalyst, either humotelinite or humocollinite may contribute to coal liquefaction in addition to humodetrinite; with pale lithotypes in the presence of catalyst, three submaceral groups may be converted.