Mechanism of the hydrogen-sulphidepromoted cleavage of the coal model compounds: diphenyl ether, diphenylmethane and bibenzyl

Abstract Hydrogen sulphide is shown to cleave the model coal compounds: diphenyl ether, diphenylmethane and bibenzyl with the major products being phenol and thiophenol, toluene and thiophenol, and toluene, respectively. These reactions were determined to be radical in nature. The sulphur which incorporated into diphenyl ether and diphenylmethane forming thiophenol was determined to reside ultimately at the ipso position. The cleavage of all three model compounds was inhibited by the presence of 316 stainless steel. The nature of the iron sulphides produced and the amount of H 2 S reacted were determined. It is concluded that 316 stainless steel and tetralin act as sulphur radical scavengers. In the absence of steel or tetralin, the conversions of the model compounds occur by radical chain mechanisms in which H 2 S acts as a reagent.