Solubilization of Coal by Alkylation with Olefin

Abstract

The treatment of coal with 1-decene has been carried out in the pre-sence of trifluoromethanesulfonic acid at 150°C under atmospheric pressure.A considerable portion of the organic material in coal was converted into pyridine-soluble product at an extremely early stage of the reaction.Subbituminous coals having 75-80% of carbon con-tent show a maximum solubility in the case of the treatment for 120 min.
Chemical structure of the solubilized product was analyzed by using ¹H-NMR spectroscopy on the basis of Brown-Ladner method.Furthermore, the treatment of pyridine-extract from parent coal was also carried out under the same condition as the treatment of the parent coal, and structural change in the coal extract was investigated.
It was confirmed from the structural analysis that alkyl groups were introduced into coal by the treatment.Increased solubility of the treated coal was attributed to the role of these alkyl groups to weaken cohesive force in coal.The alkylation mechanism that long alkyl groups were introduced initially and then rearranged into many short alkyl groups was proposed according to the analytical data.Elucidation of structural change in coal extract by the treatment allowed the consideration that some cross-linking reactions, which are regarded to decrease solubility of coal, occurred competing with the alkylation reaction.