Popis: |
The poisoning effect of various halogen compounds on a nickel-based hydrogenation catalyst has been investigated. While alkyl monochlorides did not affect the catalyst activity, alkyl monobromide and-iodide had a strong poisonous effect. Vicinal dichlorides, 1,1-dichlorides, and HC1 also poisoned the catalyst. It is shown that with chlorine containing compounds, the poisoning mechanism involves a fission of the carbon-chlorine bond with the formation of HC1, while bromine and iodine compounds adsorb to the catalyst surface as such in a simple equilibrium reaction. A mackerel oil previously shown to exhibit three kinetically distinguishable poisoning effects has been further examined, and it is shown that its content of halogens can probably account for the observed poisoning pattern. |