Catalysts Other than Cobalt and Rhodium

While cobalt and rhodium have been the focus of most research and are the metals of choice for commercial hydroformylation reactions, numerous other metals have been disclosed as catalysts in the patent literature. However, only some of the carbonyl-forming metals can be seriously considered. Even of these, a comparison of relative reactivity (118) based on cobalt as the standard indicates a decided preference for only two or three metals. This listing may be considered incomplete without the inclusion of platinum and copper, which have recently received significant attention (vide infra). 

An induction period was noted unless RuH2(CO)2(PPh3)2 was preformed, in which case none occurred. Conditions for optimum results were crit- 

The mechanism was similar to those involving cobalt and rhodium, and is depicted in Fig. 10. 

The trinuclear species Ru3(CO)i2 was less active as a catalyst unless triarylphosphines or triaryl phosphites were added, in which case the activity was greater than that of the mononuclear species. The catalytic polynuclear species was probably H4Ru4(CO)8L4. 

Platinum, as [(Ph3P)3PtH]+PF6-, showed a low activity for converting olefins to aldehydes (121). At 150°C, 1500 psi H2/CO, 5 hours reaction time, 16% of 1-hexene was converted to a mixture of aldehydes and alcohols. 

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VIII. Catalysts Other Than Cobalt and Rhodium. 53... 

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