Aldol Condensation During Hydroformylation

Frequently in the hydroformylation of olefins to aldehydes, a further reaction in varying extent (usually undesired) is aldol condensation. 

There are certain cases, however, where aldol condensation is desired. For instance, by the aldol condensation of butyraldehyde, followed by hydrogenation, one obtains 2-ethylhexanol [893,894,952], a very important 

In this way, more than two thirds of the formed n-butyraldehyde can be converted directly to 2-ethylhexanol. 

The described reactions have been carried to technical production (Esso) under the name Aldox reaction, utilizing a condensation catalyst. Compounds of Zn, Sn, Ti, Zr, Hf, Th, Pb, Cd, Hg, A1 and Cu may also be used for this purpose [709, 715-717, 757, 758, 782-785]. Shell also produces these alcohols in a similar reaction and uses KOH as a condensation catalyst [707]. 

Mg(OCH,)j Pyridine Fe(CO)s 10-2min-i n iso n iso C7H13CHO C7H15CHO 2-Ethyl- 4-methyl- pentanol 2-Ethyl- hexa- nol due 

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