ABSTRACT
The influence of surface pH of activated carbon on selectivity of titanium dioxide , (TiO2) during the photooxidation of 4-chlorophenol (4CP) on UV irradiation was studied as a promising test for verify both the environmental and green chemistry applications of nanoporous carbons. Chlorine substitution by p-hydroxylation yielding hydroquinone in equilibrium with benzoquinone and o-hydroxylation to 4-chlorocathecol were detected as the main intermediates in the photooxidation of 4CP. Changes in the surface pH of carbons from basic to closely neutral induce a remarkable increase in the production of 4-chlorocatechol 22 times higher on TiO2-AC in comparison with TiO2 alone. A mechanism of interaction between both of the solids is proposed to explain changes in both the photoactivity and photoselectivity of TiO2. In conclusion, results showed that TiO2-AC can be used as an alternative green photocatalyst in organic synthesis.
