1957 年 77 巻 9 号 p. 959-963
The Ekbom method of reducing 3-nitrobenzenesulfonyl chloride (I) with hydriodic acid was improved to effect the reduction with red phosphorus and a small amount of iodine by which a process was devised for the manufacture of bis(3-nitrophenyl) disulfide. The reaction conditions were examined in detail from the point of industrial process and it was determined that the optimal conditions were the calculated amount, one atom, of red phosphorus to one mole of (I), 1/100 the calculated 2.5 moles of iodine, reaction temperature of 80°, and reaction time of 1-1.5 hours. Further, the amount of red phosphorus was examined by the use of benzenesulfonyl chloride (II) and it was found that even with the use of less than calculated amount of red phosphorus, the reduction of (II) progresses to the disulfide (IV) and the intermediate formed in the Ekbom method, the disulfoxide (V), is not formed and further, that the use of red phosphorus in excess of the amount calculated resulted, unlike in the case of the Ekbom method, in further reduction of the disulfide (IV) to thiophenol (III). It was concluded that the reason for this is because the reduction agent in the Ekbom method is a combination of hydriodic acid and iodine while that in the present method is a natant hydriodic acid itself.