Adsorption ethylene coadsorption

Fig. 16. Estimated surface coverage of hydrogen and ethylene coadsorption under Temkin conditions. Ethylene adsorption is assumed to occur on 4 ( , a ) or 2 (b, b ) sites. Hydrogen surface coverage, curves (o, b). Ethylene surface coverage, curves (a, b ). 2 A HCIO4 electrolyte P of ethylene, 1 atm.

Another reaction model involves the compression of the ethylidyne overlayer at high pressure of ethylene. Because of repulsive adsorbate-adsorbate (ethylene-ethy-lidyne) interaction, and the expected small activation energy of ethylidyne surface diffusion, ethylene could adsorb on the metal in the small hole created near the compressed ethylidyne. Compression of this type has been detected by STM upon the adsorption of hydrocarbons on platinum and the coadsorption of CO and sulfur on both platinum and rhenium surfaces [218]. 

Adsorption of ethylene on a hydrogen-covered Fe(lOO) surface occurs without reaction at 1 lOK, but at 160K reversible insertion occurs ro give surface Fe-Et groups. These do not react with further H2, but coadsorption of CO induces reductive elimination of ethane. Similar studies with other alkenes showed that the surface alkyls formed are predominantly teiminal. 1... 

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