Equivalence of Groups in Bifunctional Reactants

The equivalence of the reactivities of the two functional groups in bifunctional reactants has also been demonstrated in many systems. The second column in Table 2-1 shows data for the esterification of a homologous series of dibasic acids  

The rate constants tabulated are the averages of those for the two carboxyl groups in each dibasic acid. The rate constants for the two carboxyls were the same within experimental error. Further, a very important observation is that the reactivity of one of the functional groups is not dependent on whether the other has reacted. As in the case of the monocar-boxylic acids, the reactivity of the carboxyl group quickly reaches a limiting value. Similar results were observed for the polyesterification of sebacoyl chloride (Table 2-2). 

H02C-(CH2) t—CO2H + 2C2H5OH -C2H502C-(CH2) ,-C02C2H5 + 2H2O 

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