PUBLICATION: CHINESE JOURNAL OF CATALYSIS

AUTHORS: Ren, Z; Liu, Y; Lyu, Y; Song, XG; Zheng, CY; Jiang, Z; Ding, YJ

 

A single-Rh-site catalyst (Rh-TPISP) that was ionically-embedded on a P(V) quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation. The [Rh(CO)I-3](2-) unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure (XANES), X-ray photoelectron spectroscopy (XPS), and Rh extended X-ray absorption fine structure (EXAFS) analyses. As the highlight of this study, Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which [Rh(CO)(2)I-2]- is the traditional active center. A TOF of 350 h(-1) was obtained for the reaction over [Rh(CO)I-3](2-), with >95% propionyl selectivity at 3.5 MPa and 468 K. No deactivation was detected during a near 1000 h running test. The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP, and the formation of two ionic bonds between [Rh(CO)I-3](2-) and the cationic P(V) framework ([P](+)) of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

 

LINKS: http://dx.doi.org/10.1016/S1872-2067(20)63676-2