Supported Catalysts Containing Ionic Media

The idea to immobilize catalytically active salts or salt solutions on a support to obtain a solid heterogeneous-like catalyst system, maintaining the selectivity and 

In a more fundamental perspective the concept of confining catalytically active salts on supports may be regarded as a branch of the common concept of supported liquid phase (SLP) catalysts, where a non- or low-volatile catalyst solution of, for example, pyrosulfates [26], hydrophilic polymer glycols [27-29], phthalates [22] or water (i.e. supported aqueous phase, SAP) [30-33] are deposited on a high-surface area porous support. 

In the literature terms such as supported molten salt (SMS) catalysts, supported ionic liquid catalysts (SILC) and supported ionic liquid-phase (SILP) catalysts, have been used somewhat indiscriminately to describe catalyst systems containing a catalytic ionic phase. In this section vye will use the terms molten salt or ionic liquid to indicate the melting point of the fluid phase in the systems. Furthermore, we will distinguish between the terms SILC and SILP. SILP is used when the ionic liquid is performing mainly as an immobihzing solvent for the catalytic components. SILC is used in cases where the ionic hquid itself, ionic hquid ions or ionic liquid-like fragments are behaving as the catalytic species. 

1 Process and engineering aspects of supported ionic iiquid catalysts 

During catalytic reactions using supported ionic liquid-type catalysts gaseous or vapor-phase reactants diffuse through the residual pore space of the catalyst, dissolve in the liquid catalyst phase, and react at catalyst sites within the thin liquid catalyst film dispersed on the walls of the pores in the support material, as illustrated in Fig. 5.6-1. The products then diffuse back out of the catalyst phase into the void pore space and further out of the catalyst particle. 

---

The hydroformylation of 1-hexene by supported ionic liquid catalysis (SILC) was recently reported by researchers at ExxonMobil. In this system, the active catalyst HRh(CO)(tppti)3 (tppti = tri(m-sulfonyl)triphenyl phosphine tris(l-butyl-3-methyl-imidazolium)) is contained within the ionic liquid phase while excess tppti ligand is immobilized in the support material. TOP values of 65 min" were obtained with silc while an unsupported biphasic ionic liquid medium gave TOP values of 23 min. ... 

---