Chemical Structurc of Asphaltene from Hydrogenated Hokkaide Coals

Asphaltene, an intermediate product in coal hydrogenation, was prepared from 5 Hokkaido coals of different ranks, and the characteristics of each chemical structure was studied to clarify the basic characteristics as raw chemical material. According to the analytical results of its chemical structure, the difference in the chemical structure of asphaltene from the different coals. and correlation of the chemical structure of asphaltene, oil (S1) and oil (S2) were discussed. The results are summarized as follows:(1) Asphaltene prepared from different coals have a comparatively similar eleme-ntary composition. However, it was considered that the aromatic ring structure of asphaltenes inherited the characteristic chemical etructures of each raw coal. It was also recgnized that the characteristics of chemical structure of asphaltene prepared from the same raw coal changed with the reaction condition.(2) The yields of Hokkaido coal asphaltene are from ca. 20% to 40-50%, and show a general increase with the carbon content of raw coal. However, it was noted Taiheiyo coal asphaltene shows a singularity in its yield, molecular weight distribution.(3) It was clarified that the molecular weight, average degree of poymerization and molecular weight distribution of oil (S2) passing through asphaltene as an intermediate product were different from those of asphaltene, but the aromatic ring structure of oil (S2) and asphaltene was similar. Moreover the chemical structure of oil (S1) formed directly from coal is considerably different from that of asphaltene and oil (S2). These facts indicate that the coal hydrogenation mechanism of formula (1) proposed on the basis of the reaction kinetic study is further supported by elucidating the characteristics of the chemical structucture of each corresponding product in formula (1), and in turn it became possible to give a further explanation of the experimental results.