Shell hydroformylation process phosphine-modified

Such tert-phosphine-modified catalysts are used industrially in the Shell hydroformylation process. This is one of many examples of the influence of auxiliary ligands (cocatalysts) on homogeneous catalysis. 

In the Shell process (SHOP) phosphine-modified cobalt-catalyzed hydrofor-mylation is one of the steps in the synthesis of linear alcohols with 12-15 carbon atoms (see Section 7.4.1). Two important characteristics of this reaction should be noted. First, the phosphine-modified precatalyst HCo(CO)3(PBu3) is less active for hydroformylation than HCo(CO)4 but more active for the subsequent hydrogenation of the aldehyde. In this catalytic system both hydroformylation and hydrogenation of the aldehyde are catalyzed by the same catalytic species. Second, the phosphorus ligand-substituted derivatives are more stable than their carbonyl analogues at higher temperatures and lower pressures (see Table 5.1). 

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. 

Phosphine-modified cobalt catalyst is applied commercially only in the Shell process to hydroformylate olefins of medium chain length (C7-C14). The resulting alcohols are sold under the brand name Dobanol . 

In the 1960s, Shell commercialized a one-step process using a phosphine modified cobalt catalyst. This process operates at a much lower pressure, provides a high selectivity for the normal aldehyde isomer, and carries out the hydroformylation and hydrogenation sequentially without isolating the aldehyde. 

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]. 

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