Following the preparation of a @[email protected] or following its @[email protected] into a catalytic reactor, it is often subjected to various treatments before the start of a catalytic run. The term pretreatment may, in general, be applied to this set of treatments. In some cases the word @[email protected] is used. It implies that the material is converted into a @[email protected] or into a very much more effective one by the pretreatment.