Catalyst poisoning

With catalyst poison for heterogeneous catalysts, contact poison, is meant a substance which permanently reduces the effect of a catalyst or canceled. Thus, it slows down a commonly desired chemical reaction.

Heterogeneous catalysts

In public, is known primarily as a lead destroyer of automotive catalysts, therefore leaded motor gasoline - alternate with tetraethyl lead as an antiknock gasoline fuel - no longer available at filling stations. Chemical catalysts can be impaired or destroyed by a variety of substances including heavy metals, halogens, polymers, sulfur, or carbon monoxide. Catalyst poisons the catalyst instead of the substance, its reaction he should accelerate bound. Thereby blocking the adsorption of the large surface of the catalyst particles.

Selective catalyst poisoning

The poisoning of a catalyst may be desirable to reduce the activity of a catalyst for a particular reaction selectively. Oxidation catalysts are selectively poisoned as to control the oxidation of primary alcohols to aldehydes and oxidize into carboxylic acids. The targeted reduction of poisoning catalysts by sulfur compounds can be achieved, for example, that are hydrogenated alkynes to alkenes, but not to alkanes.