Under mild conditions, hydroformylation of olefins with rhodium carbonyl complexes selectively produces aldehydes.A one-step synthesis of oxo alcohols is possible using monomeric or polymeric amines, such as dimethylbenzylamine or anion exchange resin analog to hydrogenate the aldehyde. The rate of aldehyde hydrogenation passes through a maximum as amine basicity and concentration increase. IR data of the reaction reveal that anionic rhodium carbonyl clusters, normally absent, are formed on addition of amine. Aldehyde hydrogenation is attributed to enhanced hydridic character of a Rh-H intermediate via amine coordination to rhodium.Hydroformvlation of olefins to aldehydes over cobalt carbonyl catalysts A -1 * is the first step in the industrial synthesis of oxo alcohols (1, 2). Reaction conditions require temperatures above 150 °C and pressures up to 3000 psig. Subsequent aldehyde hydrogénation occurs over supported cobalt or molybdenum disulfide catalysts.Addition of modifying ligands such as tributyl phosphine affords a one-step, cobalt-catalyzed synthesis of alcohols (at lower pressure), but accompanying olefin hydrogénation reduces yields (3). With amine ligands, the effects are varied. Accelerated hydroformylation rates are possible with weak bases such as pyridine, but stronger bases ( piperidine or triethylamine, for example) retard or completely inhibit the reaction (4,5).In comparison with their cobalt analogs, rhodium carbonyls are significantly more active catalysts (6). As with cobalt, aldehyde is the 240

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