Ethanol Upgrading to n‑Butanol Using Transition-Metal-Incorporated Poly(triazine)imide Frameworks

• Published in: ACS applied materials & interfaces 2023-08, Vol.15 (30), p.36384-36393
• Main Authors: Cypher, Sabrine M., Pauly, Magnus, Castro, Leslie G., Donley, Carrie L., Maggard, Paul A., Goldberg, Karen I.
• Format: Article
• Language: English
• Subjects: Energy, Environmental, and Catalysis Applications; Materials Science; Science & Technology - Other Topics
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.3c07396

The upgrading of ethanol to n-butanol was performed using a molecular catalyst integrated into a carbon nitride support, one of the first examples of a supported molecular catalyst performing the Guerbet process. Initial studies using crystalline poly­(triazine)­imide (PTI) with lithium or transition-metal cations imbedded in the support together with a base as the catalyst system did not produce any significant amounts of n-butanol. However, when using the catalyst material formed by treatment of PTI-LiCl with [(Cp*)­IrCl2]2 (Cp* = pentamethylcyclopentadienyl) along with sodium hydroxide, a 59% selectivity for butanol (13% yield) was obtained at 145 °C. This PTI-(Cp*)Ir material exhibited distinct UV–vis absorption features and powder X-ray diffractions which differ from those of the parent PTI-LiCl and [(Cp*)­IrCl2]2. The PTI-(Cp*)Ir material was found to have a metal loading of 27% iridium per empirical unit of the framework. Along with the formation of n-butanol from the Guerbet reaction, the presence of higher chain alcohols was also observed.