Sulphonation and Halogenation of Phenol

SULPHONATION: phenol with concentrated H2SO4 at 280 K gives mainly o-phenolsulphonic acid (the kinetic product), while carrying out the same reaction at 373 K gives mainly p-phenolsulphonic acid (the thermodynamic product), illustrating temperature-dependent ortho/para selectivity. HALOGENATION: phenol reacts with bromine water (an aqueous, dilute source of Br2) to give an immediate white precipitate of 2,4,6-tribromophenol (all three activated positions substituted, 3 HBr released) -- this is also used as a qualitative test for phenol. Under milder, non-aqueous conditions -- Br2 …