Reactions of nitrotoluenes with sodium sulphide: Phase transfer catalysis and role of Omega phase

The reactions of nitrotoluenes (o-, m- and p-) with sodium sulphide were ca rried out both in the liquid-liquid and solid-liquid modes with phase trans fer catalyst, tetrabutylammonium bromide (TBAB). In the liquid-liquid mode, the reactions of all three nitrotoluenes were found to be kinetically cont rolled with activation energy values of 4.71 x 10(4), 5.25 x 10(4) and 3.92 x 10(4) kJ mol(-1) with o-, m- and p-nitrotoluenes respectively as the org anic substrates. In solid-liquid mode, the reactions of o- and p-nitrotolue nes were kinetically controlled whereas that of m-nitrotoluene was found to be mass transfer controlled with an activation energy of 1.16 x 10(4) kJ m ol(-1). The effect of Omega phase on the rate of solid-liquid reaction was also studied and a maximum six-fold enhancement in rate was observed with m -nitrotoluene as the organic substrate.