Immobilization of a rhodium catalyst using a diphosphine-functionalized ionic liquid in RTIL for the efficient and recyclable biphasic hydroformylation of 1-octene

Abstract

A highly efficient and stable Rh-P catalytic system in the RTIL of [PEmim]BF4 was developed for the biphasic hydroformylation of 1-octene by using the diphosphine-functionalized ionic liquid (FIL) of 2. While 2-Rh(acac)(CO)2 was immobilized in [PEmim]BF4 (solvent), a typical biphasic catalysis was fulfilled with advantages of facile separation and recycling ability - 9 runs without any loss of activity. It was found that not only the acquired π-acceptor character of 2, but also the synergetic role of the piperidyl group in [PEmim]BF4 as an N-containing donor, cooperatively contributed to the efficient hydroformylation due to the facilitated formation and stability of the Rh-H active species (ν 2045 cm(-1)). This was supported by the in situ high-pressure FT-IR spectral analysis.

Reusable N-Heterocyclic Carbene Complex Catalysts and Beyond: A Perspective on Recycling Strategies

“…Apart from the rare example of an ionic salt tagged NHC metal catalyst dissolved in the homogeneous phase of ionic liquids (or miscible cosolvent systems composed of an ionic liquid and organic solvent, such as CH 2 Cl 2 ), other representative ionic liquid phase reactions using ionic salt tagged organometallic catalytic systems, which were reported after (or in) 2006 are summarized in Scheme . We can conclude from Scheme that hydroformylation − and hydroaminomethylation reactions have been a hot topic in this area because of the value of Rh complexes, as well as the cornerstone status of hydroformylation in the fine chemical industry, and various ionic salt tagged phosphine ligands have been designed and synthesized for use with the ionic liquids. Moreover, several ionic salt tagged phosphine palladium complexes/ionic liquids systems have been developed for classical cross-coupling reactions (Suzuki coupling, Heck coupling, and Sonogashira coupling , ).…”

A perspective on liquid salts for energy and materials

“…Ionic liquids offer near ambient temperature systems with excellent solvating ability to perform chemistry in the absence of water. A highly efficient and stable system for hydro-formylation has been developed, 14 this involves a biphasic system with a rhodium catalyst dissolved in one ionic liquid phase and a diphosphine functionalised ionic liquid in the other. This chemistry is now being applied to a range of processes including processing of biomass.…”