Abstract
n order to investigate chemical forms of organic sulfur occupying more than 80% of the total coal sulfur (mainly, bituminous coal for metallurgical use), estimations of various organic radicals containing sulfur were attempted to be made about the solvent extract of coal.And the following results were obtained.(1) In the exam-ination of the solvent for extraction of coal, tetrahydrofuran and dimethylformamide, which have been so far little used for extraction of coal, and benzene were used because of their various advantages.(2) The methods of estimations of various radicals containing sulfur were established after examination by using pure organic sulfur compounds.Then the following values of contents for various radicals were obtained concerning extracts of Miike coal: thiol (—SH) 3-9%, disulffide (—S—S—) 6-13%, sulfide which does not combine directly to the aromatic ring (—S—) and sulfidecombining in the saturated heterocyclic ring28-37%, sulfide combining directly to the aromatic ringand sulfide combining in the the hetero-cyclic ring7-19%, and undetermined—30%.(3) It is conceivable that the organic sulfur in coal extract which can be reduced by Raney nickel (corres-ponding to the total of each form determined by the above method) has greater chemical activity than the other ones in coal.And the content of this organic sulfur against the total organic sulfur in coal showed the maximum value at the rank of83-84% carbon. Therefore, it was inferred that the reactivity of organic sulfur in coal has the largest value for coal of 83-84%carbon.
