The kinetics and mechanism of polymer-based NHC-Pd-pyridine catalyzed heterogeneous Suzuki reaction in aqueous media


BOZTEPE C. , KÜNKÜL A. , GÜRBÜZ N. , ÖZDEMİR İ.

INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, cilt.51, ss.931-942, 2019 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 51 Konu: 12
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1002/kin.21321
  • Dergi Adı: INTERNATIONAL JOURNAL OF CHEMICAL KINETICS
  • Sayfa Sayıları: ss.931-942

Özet

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 x 10(-3) mol/L of phenylboronic acid (FBA), 50 x 10(-3) mol/L of bromoacetophenone (Brac), 125 x 10(-3) mol/L of K2CO3, 1 g/L of catalyst, 80 degrees 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.