METHOD OF DISSOLVING SOLID CARBONACEOUS MATERIAL

1287570 Extracting coal COAL INDUSTRY (PATENTS) Ltd 30 Dec 1969 [30 Dec 1968] 61651/68 Heading C5E A coal extract or solution is made by dissolving the coal at between 360‹ and 425‹ C. in an organic solvent, e.g. coal tar oil, to which has been added a cyclic activator, preferably nitrogenous. Solvent is recovered and recycled to the extraction step. The activator comprises either a compound having at least two carbocyclic rings or a heterocyclic ring having nitrogen as the heteroatom and which is capable of dehydrogenation which gives rise to an aromatic ring without rearrangement, or a compound having nitrogen in an aromatic ring. The activator preferably forms 3% to 5% b.w. of the solvent, which may range from 2 to 5 times the weight of the coal. Activators mentioned include 1,2,3,4-tetrahydroquinoline, indoline, indole, pyrrolidine, pyrazine, piperidine, and may be nitrogen-free, e.g. perhydrophenanthrene or 9,10-dihydroanthracene. Hydrogenated tar bases may be used. The activator may be added to used solvent, which may be topped up and recycled.