STRUCTURE-REACTIVITY CORRELATION FOR REACTIONS OF PEROXIDE ANION NUCLEOPHILES WITH SUBSTITUTED ACYLOXYBENZENESULFONATE BLEACH ACTIVATORS

Second-order rate constants are reported for the reaction between a se ries of esteric bleach activators with different acyl substituents, na mely, acetyloxybenzenesulfonate, n-butanoyloxybenzenesulfonate, n-nona noyloxybenzenesulfonate and isononanoyloxybenzenesulfonate, and a set of peroxide nucleophiles whose basicity ranges from below that of the oxybenzenesulfonate leaving group to above it. The results conform to a Bronsted-type relationship with beta(nuc), 0.42 +/- 0.01 for acetylo xybenzenesulfonate, very similar to the value of 0.40 +/- 0.01 for par a-nitrophenyl acetate and a range of peroxide nucleophiles. A signific antly larger value of beta(nuc) 0.56 +/- 0.05 is obtained with n-nonan oyloxybenzenesulfonate. This increase in beta(nuc) is interpreted in t erms of steric and polar interactions between the acyl substituent and the attacking nucleophile. The reactivity of n-butanoyloxybenzenesulf onate is similar to that of n-nonanoyloxybenzenesulfonate whilst that of isononanoyloxybenzenesulfonate is less. These results are discussed in terms of the practical consequences for bleach activation and with regard to the mechanism of acyl transfer from esters to peroxides.