Antitoxic stability

Stability of catalysts contains heat-resistant stability for high temperature and heat, mechanical stability for the effect of friction, impact and gravity as well as antitoxic stability for the effect of poison. 

There are several methods to investigate the antitoxic stability of catalysts. 

Table 11. Stability constants of the Na+ complex and antitoxic activity of antamanide and some...

One or more stable conformations can also be assumed for cyclic peptides which can adopt more or less rigid structures stabilized by hydrogen or other bridges or, strongly, by complexing various metal ions. As an example of many published structures [41], there is the Li-complex of the antitoxic mushroom peptide antamanide (see p. 215), a structure which was determined in 1973 by Isabella L. Karle [42] using the direct method of Jerome Karle (Nobel Prize 1987, shared with J.A. Hauptmann). 

The required amount of catalyst is not proportional to the increase of yield of ammonia. In the past decades, the amount of catalyst required per ton of ammonia has been reducing. One reason is that the quality or purification of syngas is continuously improved. Another is that the heat stability and antitoxic property of catalysts is increased which prolong the usage life of the catalyst. At the same time, by reducing the pressure class in synthesis loop, the volume of catalyst used is increased significantly. 

---