Formic acid dehydrogenation by [Ru(η6-benzene)(L)Cl] catalysts: L = 2-methylquinolin-8-olate and quinolin-8-olate

Abstract

The [Ru(η⁶-benzene)(L)Cl] (complex 1, L = 2-methylquinolin-8-olate and complex 2, L = quinolin-8-olate) complexes were synthesised and employed for the dehydrogenation of formic acid (FA) in the presence of sodium formate. The catalytic activity of the complex was studied at different temperatures and by varying the HCOOH, HCOONa, and complex concentrations. The activation energy required for the dehydrogenation of formic acid was 29.81 kJ mol⁻¹ for complex 1 and 29.83 kJ mol⁻¹ for complex 2 obtained from the Arrhenius plot, and ΔG was estimated to be 90 kJ and 83 kJ for complex 1 and complex 2 respectively from the Eyring plot. The dehydrogenation of formic acid was also studied from acidic to basic medium, and both the catalysts show the highest TOF at pH 7.0. The mechanism for the dehydrogenation of FA has been interpreted based on the spectroscopic technique. The catalytic activities are compared with some reported catalysts using manometry.