Heck metal oxide support

Table 5.5 Mizoroki-Heck reactions based on the use of Pd supported on metal oxide catalysts. 

In most cases, classical preparahon methods well known from heterogeneous catalysis have been applied for the preparation of the Pd parhcles/species supported on solids. However, the palladium parhcle size was inveshgated in detail in only a few reports in the literature. A strong influence of the preparation method, Pd particle size (dispersion) and of the chemical nature of the Pd nanoparticles (e.g. metal or oxide) has been reported in several papers. A rather complete overview of the literature on heterogeneous palladium systems applied to Heck catalysis including detailed discussion on mechanishc aspects is given in reviews by Biffis et al. [20] and Jones et al. [136] for the time before 2001 and 2006, respectively. 

Pt particles with the IL protects the catalyst from oxidation, which can be utilized to protect air-sensitive catalysts [35]. Further examples of heterogeneous reactions on metal immobilized in porous supports using ILs are Heck C-C coupling on Pd [36] benzene hydrogenation on nanoscale Ru-catalysts [37] selective acetylene hydrogenation on Pd-nanoparticles, for example, dissolved in [BMlM][PFg] [38] and citral hydrogenation on Pd immobilized by different ILs on an active carbon cloth [39]. 

Metal nanoparticles (MNPs) are excellent catalysts working under mild conditions either homogeneously or heterogenized on a solid support (zeolite, charcoal, nanotubes). For instance, Haruta discovered that AuNPs on Ti02 catalyze CO oxidation by O2 to CO2 under subambient conditions, with many applications. Alkene and arenes hydrogenation under ambient conditions and cross C-C bond formation (Suzuki, Sonogashira, Heck, Stille, Corriu-Kumada) with aryl halides are catalyzed by noble metal NPs (Ru, Rh, Pd or Pt). 

---