Hydroformylation-hydrogenation reaction

Other modification reactions of unsaturated polymers which have been reported include phosphonylation, hydration via hydroboration, nitromercuration (by phase-transfer catalysis)/" hydroformylation/ hydrogenation/ reactions with... 

In a recent study, the group of Alper gave an optimized protocol for the one-pot hydroformylation-hydrogenation reaction of several olefins under less severe pressure conditions (Scheme 1.16) [25]. Yields of up to 99% and moderate regios-electivities were achieved. 

Scheme 3.14 Tandem hydroformylation-hydrogenation reaction with carbon dioxide.

With methyl oleate, 53% yield of the terminal alcohol was observed. With unmodified internal olefins (2-decene, 2-tridecene, 4-octene), even higher regioselectivities in favor of the terminal alcohol could be achieved l/b up to 12 1). Proof was given that both rhodium and ruthenium complexes catalyze the isomerization-hydroformylation-hydrogenation reaction in a cooperative manner. 

In the hydroformylation-hydrogenation reaction, phosphine ligands are used in a slight excess (P/Co = 2 1) in comparison to the metal. In general, catalysts modified in this manner are less active in comparison to the unmodified complex HCo(CO)4. An excess of phosphine decreases the activity further. Corresponding trialkyl arsenic ligands produced less selective catalysts. Also, with arsines an increase in the temperature increased the yield of the alcohol over the aldehyde [39]. At temperatures of 150-190°C, almost exclusively alcohols were formed in yields of 80-85%. Polar solvents such as DMF (A/ ,A/ -dimethylformamide) can inhibit the hydrogenation of the aldehyde [40]. 

Figure 5.11 Phosphine ligands for cobalt-catalyzed hydroformylation-hydrogenation reactions.

This principle was extended to the tandem decarboxylative hydroformylation-hydrogenation reaction ofa,P Unsaturated carboxylic acids (Scheme 5.59) [77]. 

Scheme 6.125 Cobalt-catalyzed tandem hydroformylation-hydrogenation reaction of paraformaldehyde.

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