Low-temperature hydroformylation of ethylene by phosphorous stabilized Rh sites in a one-pot synthesized Rh-(O)-P-MFI zeolite.

Zhao, Minjie; Li, Chengeng; Gómez, Daviel; Gonell, Francisco; Diaconescu, Vlad Martin; Simonelli, Laura; Haro, Miguel Lopez; Calvino, Jose Juan et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Zeolites containing Rh single sites stabilized by phosphorous were prepared through a one-pot synthesis method and are shown to have superior activity and selectivity for ethylene hydroformylation at low temperature (50 °C). Catalytic activity is ascribed to confined Rh<sub>2</sub>O<sub>3</sub> clusters in the zeolite which evolve under reaction conditions into single Rh<sup>3+</sup> sites. These Rh<sup>3+</sup> sites are effectively stabilized in a Rh-(O)-P structure by using tetraethylphosphonium hydroxide as a template, which generates in situ phosphate species after H<sub>2</sub> activation. In contrast to Rh<sub>2</sub>O<sub>3</sub>, confined Rh<sup>0</sup> clusters appear less active in propanal production and ultimately transform into Rh(I)(CO)<sub>2</sub> under similar reaction conditions. As a result, we show that it is possible to reduce the temperature of ethylene hydroformylation with a solid catalyst down to 50 °C, with good activity and high selectivity, by controlling the electronic and morphological properties of Rh species and the reaction conditions.