3-Phenyl-propionic acid acidity constant

As the sulfate is removed and replaced by perchlorate, probable participation of a precursor complex is again indicated (Calvaruso et al. 1983). These authors observe complex dependence of the reaction rate on sulfate concentration and acidity, but unfortunately arrive at a rate law too complex to resolve any useful constants. They suggest that the oxidation occurs simultaneously through three transition states involving one-, two-, and three-coordinated sulfate molecules (Ce804L, 0(804)2L, and HCe(804)3L). These authors also conclude (Calvaruso et al. 1984) that the oxidation of lactic (2-hydroxypropionic) and atrolactic (2-hydroxy-2-phenyl-propionic) acids follow this same complex pathway. 

Aryl esters of 4-hydroxybutyric acid, 5-hydroxyvaleric acid, 2-hydroxyphenylacetic acid, and 3-(2-hydroxyphenyl)propionic acid lactonize with rate constants proportional to iopH picw (Capon et al., 1973). The second-order rate constant at 30° for lactonization of phenyl 4-hydroxybutyrate is ca. 3000 times greater than kOH for hydrolysis of phenyl acetate at 25°. Lactonization of phenyl 4-hydroxybutyrate is catalysed by acetate and phosphate buffers in... 

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