Catalyst inactivation

The various palladium species can be subject to decomposition and deposition of palladium metal, which generally leads to catalyst inactivation. Apart from their effect on the catalyst activity, the ligands and bases also affect catalyst longevity. 

Work is ongoing to quantify the relative importance of intermolecular pathways of Fe -TAML catalyst inactivation... 

Quenching Abruptly stopping a reaction by severe cooling or by catalyst inactivation in a very short time period used to stop continuing reactions in a process thus preventing further decomposition or runaway. 

A complete assessment of catalyst performance must in addition address product inhibition and catalyst inactivation. For preparative applications, the final criterion concerns the absolute value of kcao which expresses how much product can be obtained from the catalysts per unit of time. As will be seen below, several catalytic antibodies indeed turn out to perform excellently in all respects. 

Catalyst inactivation can also be brought about by inorganic basic ions. The exchange of potassium ion onto an uncalcined synthetic silica-alumina causes loss of activity. The results (Mills, Boedeker, and Oblad, 21) are given in Table IV. That inactivation was not due to a... 

Cinchona catalyst inactivation via a Friedel-Crafts-type reaction with the dicarboxylate esters has been invoked to explain eroded yields and selectivities... 

If sohd AgCl is filtered off and the solvent is removed, the remaining solid contains Au, CEES and/or CEESO moieties but no Ag. Attempted recrystalhzation of this material was unsuccessful, and Au(III) was reduced to a catalytically inactive Au(0) colloid. It is observed that once Au(0) forms in the system, it is not reoxidized, leading to an irreversible inactivation of the catalyst. However, use of the correct ratios of precursors in the presence of O2, or even ambient air, produces soluble and stable Au-based catalysts, some of which retain activity for at least one week. Most Au(I) complexes, with the exception of [Au(CN)2], disproportionate in H2O and several disproportionation equilibria have been measured. Although disproportionation is less favourable kinetically in CH3CN solution, it is possible that the catalyst inactivates by hydrolysis of the Au(I) intermediate followed by its reduction to form Au(0). ... 

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