2-phenylethanesulphonate anion

The nitration of 2-phenylethanesulphonate anion (i) and toluene-w-sulphonate anion (ii) in aqueous nitric acid containing some added perchloric or sulphuric acid has been studied.When the medium was... 

The operation of the nitronium ion in these media was later proved conclusively. "- The rates of nitration of 2-phenylethanesulphonate anion ([Aromatic] < c. 0-5 mol l i), toluene-(U-sulphonate anion, p-nitrophenol, A(-methyl-2,4-dinitroaniline and A(-methyl-iV,2,4-trinitro-aniline in aqueous solutions of nitric acid depend on the first power of the concentration of the aromatic. The dependence on acidity of the rate of 0-exchange between nitric acid and water was measured, " and formal first-order rate constants for oxygen exchange were defined by dividing the rates of exchange by the concentration of water. Comparison of these constants with the corresponding results for the reactions of the aromatic compounds yielded the scale of relative reactivities sho-wn in table 2.1. 

When the concentration of 2-phenylethanesulphonate anion was >0-5 mol 1, or when 2-mesitylethanesulphonate anion (v), " mesitylene-a-sulphonate anion, or iso-durene-a -sulphonate anion were nitrated, the initial part of the reaction deviated from a first-order dependence on the concentration of the aromatic towards a zeroth-order dependence. 

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