Acid Solutions of Nitryl Chloride Nitrations of Benzene

Abstract

The suggestion has been made by Wise and Volpe (1) that solutions made from nitryl chloride and concentrated sulfuric acid may contain the nitronium ion. This was based upon the fact that these solutions contain no chlorine. It was also found that nitryl chloride could be regenerated from the solutions by passing hydrogen chloride through them. The latter reaction was similar to that of the production of nitryl chloride using a solution of sodium nitrate in concentrated sulfuric acid. The presence of the nitronium ion in such solutions is well established. The possibility of nitrating benzene with solutions of nitryl chloride in sulfuric acid was suggested by an experiment of Shirley's. (2) A product of m- dinitrobenzene was isolated when an attempt was made to nitrate n-hexane containing benzene impurities vith such a solution. In this set of experiements, we have studied the solubility of nitryl chloride in concentrated sulfuric acid and the nature of such solutions as indicated by their nitrating power. All studies were made on the basis of yields of m-dinitrobenzene, although under certain conditions nitrobenzene is the principle product. An attempt was made to obtain a maximum yield of m-dinitrobenzene from nitryl chloride by varying the conditions of nitration. [From Introduction]