Kinetics and mechanism of p-isopropenylphenol synthesis via hydrothermal cleavage of bisphenol A.
Although bishydroxyarylalkanes are known to be reactive in high-temperature (T > 200 degrees C) liquid water (HTW), no mechanistic insight has been given to explain the reactivity of methylene bridge-containing diaryls under hydrothermal conditions. We examined the kinetics and mechanism of p-isopropenylphenol (IPP) synthesis via bisphenol A (BPA) cleavage in HTW. The cleavage reaction is first order in BPA. Cleavage of BPA in HTW occurs by specific acid catalysis, by specific base catalysis, and by general water catalysis. Under neutral conditions, the dominant mechanism is general base catalysis with water serving as the proton acceptor. We generated a detailed chemical kinetics model for the decomposition reaction based on a base-catalyzed mechanism in the literature. This three-parameter model fit the experimental data for BPA disappearance and formation of IPP and phenol and accurately predicted the yield of the IPP hydrolysis product acetone. Using acid- and base-catalyzed mechanisms, we explain the reactivity in HTW reported for other diaryl groups linked by methylene bridges and propose criteria for assessing the reactivity of methylene bridges under hydrothermal conditions.
Hunter
Shawn E
SE
Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, USA.
Savage
Phillip E
PE
D000465:Algorithms; D001559:Benzhydryl Compounds; D002384:Catalysis; D007700:Kinetics; D008956:Models, Chemical; D015394:Molecular Structure; D010636:Phenols / Q000138:chemical synthesis* / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D010636:Phenols; D014867:Water; C006780:bisphenol A; D000098826:Bisphenol A Compounds