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The kinetics and mechanism of polymer‐based NHC‐Pd‐pyridine catalyzed heterogeneous Suzuki reaction in aqueous media
Author(s) -
Boztepe Cihangir,
Künkül Asım,
Gürbüz Nevin,
Özdemir İsmail
Publication year - 2019
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.21321
Subject(s) - chemistry , catalysis , phenylboronic acid , catalytic cycle , pyridine , reaction rate , activation energy , rate determining step , yield (engineering) , reaction mechanism , organic chemistry , thermodynamics , physics
One of the most important challenges of the Suzuki reaction is a green synthesis of reaction products. In terms of economy and ecology, the Suzuki reaction details must be characterized for the industrial‐scale Suzuki reaction processes. In this paper, for the first time, a kinetic and mechanistic study on the Suzuki reaction catalyzed with hydrogel‐supported PEPPSI (pyridine‐enhanced precatalyst preparation stabilization (and) initiation) type NHC‐Pd‐pyridine composite has been investigated. To determine the rate‐limiting step, the effects of reactants and experimental conditions on the heterogeneous Suzuki reaction have been experimentally defined. The experimental results demonstrated that it is possible to reach 100% yield under the optimum reaction conditions, which were found as 75 × 10 −3 mol/L of phenylboronic acid (FBA), 50 × 10 −3 mol/L of bromoacetophenone (Brac), 125 × 10 −3 mol/L of K 2 CO 3 , 1 g/L of catalyst, 80°C of reaction temperature, 400 rpm of mixing rate, and 3 h of reaction time. The transmetalation step in the cycle was defined as the rate‐limiting step. On the basis of kinetic results, a mathematical reaction rate expression was presented assuming the steady‐state approach to steps of the catalytic cycle. The activation energy ( E a ) of the reaction was estimated to be 34.88 kJ/mol.