The photocatalytic degradation of three hydroxylated bicyclic aromatic
compounds (2,2'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl and 4-hydro
xybiphenyl) in contact with TiO2, in aqueous unbuffered solution was a
chieved. The main intermediate, in all cases, was 1,2,4-trihydroxybenz
ene. The photoxidation of this intermediate led to identified compound
s: maleic acid, muconic acid and butadiene, resulting from the aromati
c ring opening. A complete mineralization scheme for hydroxylated bicy
clic aromatic compounds can be proposed.