A Further Investigation of the Symmetrical Chloride of Paranitroorthosulphobenzoic Acid

Dissertation.
Submitted to the Board of University Studies of the Johns Hopkins University for the Degree of Doctor of Philosophy.
— by —
William E. Henderson.
1897
The author esteems it a privilege as well as a pleasure to give expression to his sincere sense of gratitude to Prof. Remsen,under whose guidance this work was carried on not only for instruction received in the lecture room, but for his frequent suggestion, and his constant and friendly interest in the work as it progressed. These have at all times been an encouragement and an incentive.
He wishes also to express his appreciation of the instruction and kindly guidance in the laboratory, of Drs. Morse and Renouf, as well as of Dr. Ames of the Physical Laboratory.
The sulphobenzoic acids have been the subject of investigation in this laboratory for a number of years past. Among the many interesting facts that have been brought to light in the course of this study, perhaps no others have been attended with more interest than the discovery of well characterized isomerism in the case of the chlorides of orthosulphobenzoic acid, and its paranitro derivative; together with the preparation of a series of isomeric derivatives of these substances. The chlorides themselves have been isolated in the crystalline condition, and have been found to differ markedly, not only in chemical, but in physical properties as well.
From evidence drawn from the action of ammonia upon these chlorides, taken in connection with a number of other facts, the higher melting chloride is identified as the one possessing a symmetrical structure, while the lower melting chloride possesses an unsymmetrical structure. The first one, when treated with ammonia is slowly transformed into the ammonium salt of paranitrobenzoic sulphinide:
CO /\ COCl /N.NH₄ /// C₆H₃—SO₂Cl + 4NH₃ = C₆H₃—SO₂ + 2NH₄Cl. \\ NO₂NO₂
while the lower melting chloride is quickly transformed into the ammonium salt of paranitroorthocyanbenzenesulphonic acid: