Hydroformylation process cobalt catalysis

A breakthrough occurred in the mid-seventies when Union Carbide and Celanese introduced Rh/phosphine catalysts in commercial processes. This catalyst is based on the work by Wilkinson s group he received the Nobel prize for his work in 1973. Rhodium-based catalysts are much more active than cobalt catalysts and, under certain conditions, at least for 1-alkenes, they are also more selective. The processes for the hydroformylation of higher alkenes (detergent alcohols) still rely on cobalt catalysis. A new development is the use of water-soluble complexes obtained through sulphonation of the Ligands (Ruhrchemie). 

In Chapter 8 we will discuss the hydroformylation of propene using rhodium catalysts. Rhodium is most suited for the hydroformylation of terminal alkenes, as we shall discuss later. In older plants cobalt is still used for the hydroformylation of propene, but the most economic route for propene hydroformylation is the Ruhrchemie/Rhone-Poulenc process using two-phase catalysis with rhodium catalysts. For higher alkenes, cobalt is still the preferred catalyst, although recently major improvements on rhodium (see Chapter 8) and palladium catalysts have been reported [3],... 

Relatively few hydroformylations using supported cobalt complexes have been reported. Moffat (78, 79) showed that poly-2-vinylpyridine reversibly reacted with both Co2(CO) and HCo(CO)4, the cobalt carbonyl being displaced by excess carbon monoxide. This enabled the polymer to pick up the cobalt carbonyl at the end of the reaction and, thus, allowed it to be separated from the products by filtration. The polymer acted as a catalyst reservoir by rapidly releasing the cobalt carbonyl into solution in the presence of further carbon monoxide, so that the actual catalysis was a homogeneous process. More recently, cobalt carbonyl has been irreversibly bound to a polystyrene resin... 

Phosphine-modified cobalt hydroformylation is only used commercially by Shell. It is tightly coupled to Shell s Higher Olefins Process (SHOP, see Metathesis Polymerization Processes by Homogeneous Catalysis) that produces a C4 through C20 mixture of linear, internal alkenes for hydroformylation to detergent-grade alcohols. 

Among the most significant developments in the field of catalysis in recent years have been the discovery and elucidation of various new, and often novel, catalytic reactions of transition metal ions and coordination compounds 13, 34). Examples of such reactions are the hydrogenation of olefins catalyzed by complexes of ruthenium (36), rhodium (61), cobalt (52), platinum (3, 26, 81), and other metals the hydroformylation of olefins catalyzed by complexes of cobalt or rhodium (Oxo process) (6, 46, 62) the dimerization of ethylene (i, 23) and polymerization of dienes (15, 64, 65) catalyzed by complexes of rhodium double-bond migration in olefins catalyzed by complexes of rhodium (24,42), palladium (42), cobalt (67), platinum (3, 5, 26, 81), and other metals (27) the oxidation of olefins to aldehydes, ketones, and vinyl esters, catalyzed by palladium chloride (Wacker process) (47, 48, 49,... 

Hydroformylation. Experiments with supported cobalt catalysts led to the hydroformylation (or 0X0) process for the conversion of olefins and synthesis gas to aldehydes. Homogeneous catalysis followed, and is now used exclusively. The generally accepted mechanism involves the following reactions ... 

The favorable effects of phosphine ligands in catalysis have been known for more than half a century. One of the first reports involves the use of triphenylphosphine in the Reppe chemistry, the reactions of alkynes, alcohols and carbon monoxide to make acryhc esters [2]. An early example of a phosphine-modified catalytic process is the Shell process for alkene hydroformylation nsing a cobalt catalyst containing an alkylphoshine [3]. 

The hydroformylation of olefins is a type of CO insertion reaction that is one of the most important industrial applications of homogeneous catalysis with transition metal complexes (208,209). Conventional industrial processes (e.g., the Oxo process) typically use either cobalt- or rhodium-based catalysts and conduct the reaction in two-phase gas-liquid reactors. Efficient transfer of the reactants from the gas phase into the liquid phase is of primary importance to minimize inherent mass transfer limitations (208). Reactor design thus focuses on optimizing this mass transfer rate by maximizing the interfacial area between phases. An SCE process eliminates this transport restriction since the hydrogen... 

The coordination chemistry of the cobalt triad has received considerable attention in the areas of organometallic reaction mechanisms and homogeneous catalysis (82-84), Of particular interest have been processes such as hydrogenation, carbonylation, and hydroformylation, where the oxidative addition of substrate C-X or H-X bonds to coordinatively-unsaturated M(I) centers plays a critical role. Systems which have received the most attention thus far have been electron-rich... 

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