The Behaviors of Dissolved Sulfur in Various Organic Solvents

Abstract

The behaviors of various sulfur compounds in the petroleum have not been fully investigated. For example, the fact that the reduction wave of elemental sulfur in a certain petroleum fraction cannot be seen even its existence can be proved chemically, has not been illustrated well. And though some knowledges regarding photochemical change of sulfur compounds in the naphtha fraction, which cause troubles under sunlight, have been advanced, only equivocal explanations have been given.For elucidating of such problems, the author has studied the structure of dissolved molecule of elemental sulfur in various organic solvents using ultraviolet absorption spectroscopy and polarography, and discussed its photochemical reaction.It has been definitely shown by these experiments that elemental sulfur does not always follow the S8 ring structure, but behaves as S2 molecule in some organic solvents. When it is regarded as S2 molecule in any solvents, the polarographical reduction wave does appear and the dissolved sulfur reacts considerably with the medium solvents by ultraviolet irradiation, but in the case of S8 ring, such phenomena never occur. For example, the reduction wave of the dissolved sulfur appears in methanol but it doesn't in benzene. In the former, it can be found that some reaction is produced, such as sulfuration after ultraviolet irradiation, but in the case of the latter, nothing is found.