Exceptionally stable Rh-based molecular catalyst heterogenized on a cationically charged covalent triazine framework support for efficient methanol carbonylation

Abstract

Direct carbonylation of methanol into methyl acetate and acetic acid using Rh-based heterogeneous catalysts is of great interest due to their effective levels of activity and stability. Here, a Rh-based molecular catalyst heterogenized on a charged 1,3-bis(pyridyl)imidazolium-based covalent triazine framework (Rh-bpim-CTF) was synthesized and characterized to have a single-site distribution of metal molecular species throughout the support by its ligation to abundant N atom sites. Methanol carbonylation was performed using the Rh-bpim-CTF catalyst in a plug-flow reaction in the gas phase, affording a turnover frequency of up to 3693 h⁻¹ and a productivity of 218.9 mol kg⁻¹ h⁻¹ for acetyl products with high stability.