Equilibrium cobalt catalysis

Supported Cobalt Catalysts. Experiments were conducted with [Co(PC)]/Si02 at 340°C to determine the important variables for the catalysis of a typical [M(PC)]. Table IV gives the results for runs which were conducted for varying periods of time. It is seen that even at 100 hr. the conversion only reached 36%. The equilibrium conversion at 342°C can be estimated to be 97%. (9) Thus, the reaction is quite far from equilibrium even at long times. This may be taken as evidence for product inhibition of the catalysis. This might be expected since tetrahydroquinoline is a stronger Lewis base than quinoline. Thus, the product could bind to the metal center and prevent activation of the substrate and/or hydrogen. One important conclusion is that the reaction is not over in 24 hours and it can be assumed that the difference in conversions noted in Table I with different [M(PC)] are due to differences in inherent activity of the [M(PC)]. 

Hvdrofonnybtion is a homogeneous catalysis reaction which employs a coordination complex of cobelt with the olefin. The catalyst precursor is a cobalt salt which is converted tn siru, in the presence of CO and H , to cobalt tetracarbonyl hydride in equilibrium with cobalt tricarbonyl hydride. The latter, which displays a vacant coordination position, forms a complex with the olefm. The olefin undergoes chemical conversions leading to the production of two isomeric aldehydes, and the normal aldehyde is favored in relation to the iso-compound in the ratio of 4/1. 

The observation that charcoal catalyzes the basic aquation of hexaammine-cobalt(III) had been noted in literature, and JB observed that this catalysis was accelerated in the presence of cobalt(II). These observations were the basis for the equilibrium studies that now will be described. 

Metal Ion Catalysis.—Mercury(u). The most commonly encountered catalyst for aquation of cobalt(m) complexes is mercury(n). In aquation of a series of complexes c y-[Co(en)2LCl] +, where L = an alkylpyridine, the mechanism proposed is a rapidly established pre-equilibrium... 

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