Homogeneous and two phase sulphonation of some aromatic hydrocarbons

Abstract

The two phase sulphonation of benzene, toluene and p-xylene with concentrated sulphuric acid has been studied in a one litre batch reactor. The kinetic rate constants as a function of sulphuric acid concentration and the overall mass transfer coefficient times the interfacial area per unit volume of the acid phase as a function of agitation speed have been determined. The rates of sulphonation of toluene and p-xylene relative to that of benzene in the range 15.5-1 7 mol/litre sulphuric acid have been found to be 64 and 280 respectively. Finally, it has been shown that in aromatic sulphonation no linear relationship exists between the logarithms of the partial rate factors and the relative cation localisation energies. This is in contrast to the behaviour of some other electrophilic aromatic substitution such as halogenation, but is similar to aromatic nitration. 14 15 16 17 [Hz SO,] (mol /litre)