Influence of oxygen and iron in the liquid-phase hydrogenation of [alpha],[beta]-unsaturated aldehydes
- Chalmers Univ. of Technology, Goeteborg (Sweden)
The effect of oxygen and FeCl[sub 2] additions to the liquid-phase hydrogenation of the two [alpha],[beta]-unsaturated aldehydes, cinnamaldehyde and 2-ethyl-hexenal, was investigated over a Pt/Al[sub 2]O[sub 3] catalyst. The addition of small amounts of oxygen to the feed considerably improved the activity in both the presence and absence of FeCl[sub 2]. Without oxygen and FeCl[sub 2], the hydrogenation of 2-ethyl-hexenal to the saturated alcohol proceeded mainly via hydrogenation of the C[double bond]C double bond to yield the saturated aldehyde as intermediate. In the hydrogenation of cinnamaldehyde, on the other hand, the C[double bond]C and the C[double bond]C double bonds were hydrogenated at the same rate, yielding equal amounts of the saturated aldehyde and the unsaturated alcohol as intermediates. Addition of oxygen in the latter case increased the hydrogenation rate of the C[double bond]C double bond more than that of the C[double bond]O double bond, resulting in a decreased selectivity toward the unsaturated alcohol. The selectivity toward the unsaturated alcohol was in all cases enhanced by the addition of FeCl[sub 2]. High yields of the unsaturated alcohols were obtained by the addition of oxygen to the FeCl[sub 2]-promoted Pt/Al[sub 2]O[sub 3] catalyst. The effect of FeCl[sub 2] on the hydrogenations over a Pd/Al[sub 2]O[sub 3] catalyst was also investigated. The unsaturated aldehydes were rapidly hydrogenated to the saturated aldehydes in both the presence and absence of FeCl[sub 2]. The further hydrogenation of the C[double bond]O double bond to the alcohols was extremely slow, but was somewhat increased by the addition of FeCl[sub 2]. No unsaturated alcohols were ever observed using the Pd/Al[sub 2]O[sub 3] catalyst. 11 refs., 5 figs., 2 tabs.
- OSTI ID:
- 5719730
- Journal Information:
- Journal of Catalysis; (United States), Vol. 142:2; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALDEHYDES
HYDROGENATION
ALUMINIUM OXIDES
CATALYTIC EFFECTS
IRON CHLORIDES
OXYGEN
PALLADIUM
PLATINUM
CATALYSTS
CHEMICAL REACTION YIELD
REACTION INTERMEDIATES
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
IRON COMPOUNDS
METALS
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YIELDS
400201* - Chemical & Physicochemical Properties