Freund reaction experimental

Experiments by Freund and Spiro/ with the ferricyanide-iodide system showed that the additivity principle held within experimental error for both the catalytic rate and potential when the platinum disk had been anodically preconditioned, but not when it had been preconditioned cathodically. In the latter case the catalytic rate was ca 25% less than the value predicted from adding the current-potential curves of reactions (15) and (16). This difference in behavior was traced to the fact that iodide ions chemisorb only on reduced platinum surfaces. Small amounts of adsorbed iodide were found to decrease the currents of cathodic Fe(CN)6 voltam-mograms over a wide potential range. The presence of the iodine couple (16) therefore affected the electrochemical behavior of the hexacyanofer-rate (II, III) couple (15). 

Most experimental reports on the dependence of the rate of reaction on the concentration of nanoparticles in solution provide similar conclusions. The earliest study on this dependence sums up these conclusions and was conducted by Freund and Spiro [19] using colloidal gold solutions to catalyze the reduction of ferricyanide by thiosulfate. As the concentration of nanoparticles increases, there is a linear increase in the reaction rate, which is expected whether the catalytic mechanism is heterogeneous or homogeneous. They reported that the strength of this dependence on concentration was dependent on the size of the gold nanoparticles. While it was postulated that the catalysis occurred on the surface of the particle, these results do not prove that the catalysis is heterogeneous, but only that the catalyst concentration increases as the particle concentration is increased. 

An adjuvant is vital for the success of an immunization. It works as a depot for the antigen and increases the immunological reaction of the animal. There are many adjuvants. Among experimenters, the most popular one is Freund s adjuvant (FA). Pierce offers two adjuvants, Imject Alum and AdjuPrime, which supposedly are better tolerated by the animal to be immunized. 

The calculated BDEs for reaction (23) and (24) are around 56 kcal/mol. As was suggested by many experimental studies (Freund 1992 Lewan 1998), most of the n-alkylaromatics and NSO functional groups are much more reactive (have much weaker bonds) and may enhance the over kerogen thermal cracking. Besides the much lower BDEs, the weak linkages may also generate radicals that are more reactive and hence will... 

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