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Selective hydrogenation of acetylene (ethyne) in ethylene (ethene) streams for polyethylene production

Ethyne poisons the catalysts used for the production of polyethylene so ethyne conventrations have to be reduced to very low levels. Novel catalysts have been developed for the selective hydrogenation of ethyne in the presence of a large excess of ethene by addition of cerium to the standard palladium catalyst.

 

Electron Probe MicroAnalysis (EPMA) shows that the cerium and palladium are close together in the selective catalyst.

 

The effect of cerium is to strngthen the adsorption of carbon monoxide which blocks the hydrogenation of ethyne to ethane.