The catalyst will lose its activity rapidly or slowly under the influence of various factors during its use. The reasons for catalyst deactivation are complex, and the editor of polyurethane catalysts can be summarized as the following varieties:
1. Permanent deactivation
The active components of the catalyst are affected by some foreign components (poisoning) and loses activity, usually permanently. Most of these foreign components have chemical reactions or ion exchanges with the active components of the catalyst, resulting in changes in the active components. For example, the acidic catalyst is neutralized by alkali, and the noble metal catalyst is poisoned by sulfide or nitride. Catalyst poisoning deactivation usually manifests as a rapid decrease in activity. The loss of active components by abrasion or sublimation during use also leads to permanent inactivation, which is usually difficult to recover easily.
3. Wrong operation leads to catalyst deactivation, such as too high reaction temperature, severe pressure fluctuations lead to confusion or destruction of the catalyst bed, etc., what is the reason for the deactivation of the catalyst? is irrecoverable.
2. The active components are covered and gradually inactivated, and the right and wrong are permanently inactivated. For example, the carbon deposition generated during the reaction covers the active components or blocks the pores of the catalyst, so that the reactants cannot contact the active components. These coverings can be removed by certain methods. If they are deactivated by carbon deposition, they can be regenerated by burning charcoal for regeneration.
Tag:    Polyurethane Catalyst
