X. And, W. Jenks
Nov 11, 2000
Citations
0
Influential Citations
27
Citations
Journal
Journal of the American Chemical Society
Abstract
The partial TiO2-mediated photocatalytic degradation of anisole has been studied using isotopically labeled substrates and comparisons to Fenton and hν/H2O2 chemistry. An H/D isotope selectivity of 2.7 is observed for hydrogen abstraction from the methyl group in all cases. An 18O tracer study shows that anisole is simultaneously converted to phenol by both ipso attack and degradation of the methyl. The isotope selectivity for hydroxylation of anisole is reported to be about 1.3 under all conditions. This is attributed to an O2-dependent competition along the reaction pathway that can be avoided by use of benzoquinone instead of O2 as an electron acceptor with TiO2. Under those conditions, the H/D isotope selectivities are between 0.9 and 1.0, as would be expected for inverse secondary kinetic isotope effects.