Oxidative chlorination of aromatic compounds in the presence of sulphuric acid

Oxidative liquid-phase chlorination of benzene, phenol, toluene, ethyl benzene, and xylenes using a mixture of hydrochloric acid and hydrogen peroxide as the chlorinating agent has been studied. It has been established that, with an equimolar ArH/HCl/H2O2 ratio, t=20°C, and a time of 7 hr, the yield of chloroaromatic compounds does not exceed 30 wt.%. The use of sulphuric acid (1.0 mole H2SO4 per 1 mole HCl) as the catalyst enables this yield to be increased to 90.5 wt.%. It has been found that the oxychlorination rate of aromatic compounds depends linearly on the concentration of sulphuric acid. It has been shown that the use of sulphuric acid as the catalyst makes it possible to increase the effectiveness of hydrochloric acid in synthesis of chloroaromatic compounds.