Lindlar catalyst
A Lindlar catalyst is a
alkanes). It is named after its inventor Herbert Lindlar
.
Synthesis
Lindlar catalyst is commercially available but can also be created by reducing
palladium chloride in a slurry of calcium carbonate (CaCO3) and adding lead acetate.[1][2] A variety of other "catalyst poisons" have been used, including lead oxide and quinoline
. The palladium content of the supported catalyst is usually 5% by weight.
Catalytic properties
The catalyst is used for the
alkanes). The lead serves to deactivate the palladium sites, further deactivation of the catalyst with quinoline or 3,6-dithia-1,8-octanediol enhances its selectivity, preventing formation of alkanes
. Thus if a compound contains a double bond as well as a triple bond, only the triple bond is reduced.
An example being the reduction of phenylacetylene to styrene.
Alkyne hydrogenation is
cis-alkene.[3] For example the hydrogenation of acetylenedicarboxylic acid using Lindlar catalyst gives maleic acid rather than fumaric acid
.
An example of commercial use is the
vitamin K1.[4]
See also
- Rosenmund reduction, a reduction using palladium on barium sulfate, poisoned with sulfur compounds.
- Urushibara Nickel, a nickel based catalyst used to hydrogenate alkynes to alkenes.
References
- .
- .
- ; Collected Volumes, vol. 8, p. 609.