2- Hexenal homogeneous catalysis

Homogeneous catalysis with defined soluble transition metal complexes as catalysts has become one of the most effective means of transforming simple olefins into more valuable materials. The technically important hydroformylation of olefins to aldehydes or alcohols the Wacker process the dimerization of propylene to linear hexenes the oligomerization of ethylene to linear a-olefins are only a few examples. A feature common to all these processes is the insertion of a substrate olefin molecule, which is coordinatively bonded to the transition metal center M, into a metal-carbon or metal-hydrogen bond present at the same center ... 

Table 5.6-3 Evaluation of the hydroformylation reaction ofi-hexene to form n,iso-heptanal using supported ionic liquid phase catalysis (SILP), biphasic catalysis and homogeneous catalysis [88]...

Tables Evaluation of the hydroformylation reaction of 1-hexene to form n,/-heptanal using supported ILcatalysis (silc), biphasic catalysis, and homogeneous catalysis [14].

Crabtree described the use of dibenzo[a,e]cyclooctatetraene, a potent selective poison of homogeneous hydrogenation catalysts, as a tool to distinguish between homogeneous and heterogeneous catalysis in the hydrogenation of hexene with a range of catalysts [24]. 

For example, the homogeneous base case with 1-hexene as a substrate showed a fej, of 0.4 min at a reaction temperature of 50 °C, while the supported IL catalyst achieved a fejj of 11.2 min for the same reaction at 30 °C. The enhanced activity of the rhodium complex in an IL phase had been observed previously and may be explained by the absence of any coordinating solvent [17]. In an acetone solution under hydrogen pressure the complex exhibited coordination of two solvent molecules to the metal center. In theory, if the catalysis is carried out in an IL... 

Fig. 23.17 Scheme showing catalysis with f-element organometcdlics homogeneous l-hexene hydrogenation at 25°C and 1 atm Hz-... 

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