Using the isotope dilution technique, the distribution of isomers was determined when iodobenzene was sulfonated with sulfur trioxide in liquid sulfur dioxide. The active isotope was S^35. Before this distribution could be established, it was necessary to prepare the pure isomers of iodobenzenesulfonic acid. These were prepared by diazotization of the corresponding aminobenzenesulfonic acids. Since o-aminobenzenesulfonic acid was not readily available, it was necessary that it be synthesized before the diazo reactions could be carried out. Considerable work has been done on the development of a method whereby the bromobenzenesulfonic acids could be synthesized and obtained in pure form. Some work has been done in preparing the isomers of chloro-benzenesulfonic acid. The S-benzylisothiuronium derivatives of the iodo-, and amino-, and bromobenzenesulfonic acids have been prepared, purified and their melting points determined. It has been established, that when iodobenzene is sulfonated there is considerable replacement of the iodine by sulfure trioxide to form benzenesulfonic acid. When p-iodobenzenesulfonic acid was subjected to sulfonation conditions, there was essentially no exchange between the sulfonic acid group and the sulfonation agent, from which we concluded that under these conditions, there was negligible reversibility.
College and Department
Physical and Mathematical Sciences; Chemistry and Biochemistry
BYU ScholarsArchive Citation
Knight, Joseph A., "The isomer distribution in the sulfonation of iodobenzene" (1957). Theses and Dissertations. 8291.