Kinetics of oxidation of hydroquinone to p-benzoquinone catalyzed by microporous metal-organic frameworks M-3(BTC)(2) [M = copper(II), cobalt(II), or nickel(II); BTC = benzene-1,3,5-tricarboxylate] using molecular oxygen

The kinetics of oxidation of hydroquinone (H(2)Q) to p-benzoquinone (Q) catalyzed by microporous metal-organic frameworks (MOFs) using molecular oxygen has been investigated. MOF catalysts with different metals and pore sizes, i.e. M-3(BTC)(2)(H2O) (x) (M = Cu-II (1), Co-II (2), or Ni-II (3); BTC = benzene-1,3,5-tricarboxylate; x = 3 for MOF 1 and 12 for 2 and 3), were used to catalyze the oxidation reaction. The apparent first-order reaction rate constant increased with increasing temperature, molar ratio of catalyst/H(2)Q, and pH of the medium. A kinetic model for the heterogeneous catalysis is proposed, and the apparent activation energy (E (a)), the association constants between the hydroquinone and the catalyst (K (s)), and the first-order rate constants for product formation in the MOF channels (k (N)) were calculated.