Complex system stoichiometric table

For a complex system, determination of the stoichiometry of a reacting system in the form of the maximum number (R) of linearly independent chemical equations is described in Examples 1-3 and 14. This can be a useful preliminary step in a kinetics study once all the reactants and products are known. It tells us the minimum number (usually) of species to be analyzed for, and enables us to obtain corresponding information about the remaining species. We can thus use it to construct a stoichiometric table corresponding to that for a simple system in Example 2-4. Since the set of equations is not unique, the individual chemical equations do not necessarily represent reactions, and the stoichiometric model does not provide a reaction network without further information obtained from kinetics. 

The values of the kinetic parameters [25, 51] are listed in Table II. Using overall stoichiometric processes rather than elementary steps for describing a complex kinetic system will yield valid results only if there is no significant interaction between the intermediates of the component processes, i.e., no cross reactions, and if no intermediates build up to high concentrations. If these conditions hold, we can preserve the accuracy and simplicity of formal kinetic rate equations without having to assume rate constants for elusive elementary processes. This method has proven fruitful in describing several complex systems [18, 52, 53]. 

The 4 A Molecular Sieves System. The initial procedure for the Sharpless reaction required a stoichiometric amount of the tartrate Ti complex promoter. In the presence of 4 A molecular sieves, the asymmetric reaction can be achieved with a catalytic amount of titanium tetraisopropoxide and DET (Table 4-2).15 This can be explained by the fact that the molecular sieves may remove the co-existing water in the reaction system and thus avoid catalyst deactivation. Similar results may be observed in kinetic resolution (Table 4-3).15... 

Non-integer, net proton coefficients are reasonable considering the complexity of heterogeneous systems (q.v., Table I). Although integer stoichiometric coefficients are appropriate for microscopic subreactions, arbitrarily extending stoichiometric relationships used in microscopic reactions to macroscopic partitioning expressions is unwarranted. 

Uniquely, the Cu +-neomycin B system has been shown to form two-centered copper complexes at pH values below 6.5 if the metal ion is present in excess (Table 8.3) with less than 15% (relative to total Cu + present) of mononuclear species detected at pH values in the range of 4 to 6. At a 2 1 Cu + neomycin B stoichiometric ratio it was shown that only the dinuclear species exists in solution at pH 7.5. The second binding site in the dinuclear complex was proposed to be in ring D, however, this unique feature is only observed in the case of the copper complex of neomycin B. 

Similarly, superoxorhodium complexes also react with the hydrides in stoichiometric (ligand systems different) or catalytic (ligand systems identical) reactions, as shown in Eq. (15) and (3)-(4), respectively (50,70). As can be seen from the kinetic data in Table V, steric effects play a major role as demonstrated by a large decrease in... 

In an attempt to understand the fundamental hydronation chemistry of bridged N2 complexes, we developed the system based on [ M(S2CNEt2)3 2(li-N2)] (M = Nb or Ta, the same group of the Periodic Table of the Elements as V). These systems have the advantages that they react with an excess of acid to give stoichiometric yields of N2H4, and the reactants and products have been... 

The copper and palladium transition metal catalysts noted in Table 18 proved to be superior to nickel, ruthenium and rhodium catalysts. The nature of the reacting species has not been unequivocally defined, but the following experimental observations may provide some insight (i) tetrahydrofuran solvent is essential for the palladium-mediated reactions, since complex reaction mixtures (presumably containing carbinols) were observed when the reactions were performed in either benzene or methylene chloride (ii) the reaction is truly catalytic with respect to palladium (2 mmol alkylaluminum, 0.05 mmol of Pd(PPh3)4), whereas the copper catdyst is stoichiometric and (iii) in the case where a direct comparison may be made (entries 1-8, Table 18), the copper-based system is superior to palladium catalysis with regard to overall yield. 

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