Phosphorus additives, relative poisoning

The Relative Poisoning Powers of Lead and Phosphorus Additives. 

Comparison of Phosphorus and Lead as Poisons. In order to assess the relative toxicities of the two major poisons of noble metal oxidation catalysts, simulated tests were run with the loss of catalyst activity for HC conversion measured as a function of the TBP and the TEL in the feed, these being representative of additives in commercial fuels. 

In general, organophosphorus compounds show relatively low thermal stability. They decompose relatively quickly under the process conditions, either being converted to phosphorus pentoxide, or in the presence of water vapour to higher, condensed phosphoric acids. It is phosphorus compounds such as these which reach the surface of the catalyst. Most researchers have concluded that phosphorus poisoning is non-selective and can therefore additionally serve as a model for other non-selective poisons such as lead and zinc. Most researchers have... 

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