Ionic Attachment as a Feasible Approach to Heterogenizing Anionic Solution Catalysts. The Carbonylation of Methanol

摘要

Few definitive examples of ionically supported anionic transition metal complexes for use in catalysis have been reported, even though there are several advantages to be gained from such systems. To demonstrate the feasibility and usefulness of such materials in catalysis, we investigated the (Rh(CO)2I2)- catalyzed carbonylation of methanol to acetic acid. The ionically supported (Rh(CO)2I2)- species was found to be equal in catalytic activity to the homogeneous complex, and leaching of the catalyst could be eliminated by suitable choice of solvent and resin/rhodium ratios. Additionally, we investigated the usefulness of a solid phase acid in catalyzing the formation of CH3I from NaI (NaI by itself is inactive). We found this acid catalyst was active in this regard, and that the acidity was retained within the solid phase. These experiments suggest a general application of anion exchange resins as a mechanistic tool for detecting catalysis by anionic species in homogeneous processes. (Author)