Solid-Supported Ionic Liquid Phase Hydroformylation

Solid-Supported Ionic Liquid Phase Hydroformylation 

In 2005, Riisager and Wasserscheid [109] linked a Rh(Sulfoxantphos) complex via [BMIM] [n-CgHj yOSOg] on a partly dehydroxylated silica support. In the hydroformylation of propene, a large dependence on the nature of the support and especially the P/Rh ratio was found. Fast deactivation took place at a small excess of the ligand. The stability of the supported ionic liquid phase (SILP) catalyst was directly related to the degradation of the catalytically active complex. 

The choice of the ionic liquid was less important. Some years later, Haumann et al. 

The process was run over 500 h without significant loss of the phosphite ligand. 

Supercritical Fluld-lonic Liquid Biphasic System (SCF-SILP) 

---

Solid-Supported Ionic Liquid Phase Hydroformylation... 

The term Supported Ionic Liquid Phase (SILP) catalysis has recently been introduced into the literature to describe the heterogenisation of a homogeneous catalyst system by confining an ionic liquid solution of catalytically active complexes on a solid support [68], In comparison to the conventional liquid-liquid biphasic catalysis in organic-ionic liquid mixtures, the concept of SILP-catalysis offers very efficient use of the ionic liquid. Figure 7.10 exemplifies the concept for the Rh-catalysed hydroformylation. 

Supported liquid-phase catalysis,in which the catalyst is dissolved in a small volume of solvent, adsorbed on, usually, a hydrophilic solid, seeks to resolve issues associated with substrate solubility in multi-phase catalysis and performance/catalyst leaching in supported catalysis reports on the hydroformylation of long-chain alkenes under both supported aqueous phase and supported ionic liquid-phase regimes have been reported. 

Another highly efficient protocol for the hydroformylation consists in the combination of an ionic liquid with a solid support material (Figure 6.1). This process denominated supported ionic liquid phase (SILP) catalysis is a concept that combines the advantages of ionic liquids with those of heterogeneous support materials and allows the use of fixed-bed reactors for continuous reactions. 

---