Characterization of Catalyst by Modifying Technique

As the surface condition of catalyst reflects the EDA of MRNi as already mentioned, the EDA is a very sensitive parameter from which to get information on the surface character of the catalyst. For example, when MAA is used for the substrate, a 1 x 10 3 (%) change of the surface condition is observable, because the optical rotation of optically pure MHB is 22.95° 

In this section, the characterization of surface conditions of nickel catalysts by means of modifications with NaBr and (R,R)-TA will be introduced as an example (49). 

In the modification with TA and NaBr, NaBr adsorbs on the surface areas where TA does not adsorb and unstably adsorb as already mentioned in Section IV,A, 1, e. The correlation diagram between the fractional saturating ratio of NaBr (/) on the surface of the catalyst and the EDA of the modified catalyst as shown in Fig. 32 can be deduced from the diagram of correlation between the EDA of the modified catalyst, the amounts of NaBr and TA adsorbed, and the concentration of NaBr in the modifying solution as shown in Fig. 11. 

When the rates of the enantio-differentiating hydrogenation ( ) and non-enantio-differentiating hydrogenation (N) are postuated to be equal, and the EDA at the enantio-differentiating site is defined as 100%, the following equation is derived  

In the equation P-I and P-II are the parts on the surface area where enantio-differentiation and non-enantio-differentiation proceed, respectively. P-IIa is a portion of P-11 where NaBr cannot block the hydrogenation, and P-IIb is another part of P-II where NaBr can inhibit the hydrogenation. 

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