Kinetics and mechanism of in situ bromohydroxylation of cinnamic acids by sodium bromate-sodium bisulphite reagent in aqueous acetonitrile medium

摘要

Rates of bromohydroxylation of 4-substituted cinnamic acids with HOBr,produced in situ from sodium bromate-sodium bisulphite reagent have been studied in aqueous acetonitirile medium iodometrically. Thermodynamic parameters for the adduct formation step and the activation parameters for the first order decomposition of the adduct step have been evaluated in the temperature range 303 to 318 K and discussed. The influence of the substituents on the first order decomposition rate constant (k/s~(-1))of the adduct has been investigated. The corresponding bromodydrins of cinnamic acids have been identified as the reaction products.