Rate coefficient lactams

Even without taking into account side reactions changing the concentrations of the active species, a great number of rate and equilibrium constants are required in order to describe the whole course of polymerization. So far, no data are available on equilibrium (25) from which the concentrations of lactam and polymer amide anions could be estimated. Therefore, the individual rate coefficients can be obtained only from measurements of the initial rates of the isolated reactions. In this case, the participation of the reaction products in subsequent reactions can be neglected. 

Similarly, any compound consuming the acyllactam growth centres (e.g. primary and secondary amine [162, 170]) decreases the rate of polymerization. So far, the rate coefficients 21 of the addition of the first lactam anion to the growth centre have been estimated only for a few monomers. In most cases, however, the published rate coefficients were calculated from the second order rate equation... 

Rate coefficients of reaction (24), fep, and (66), kg, in tetrahydrofuran at 25°C (The figure in the lactam anion indicates the number of ring atoms.)... 

It has to be stressed, however, that only a fraction of the initial concentration of acyllactam and lactamate is present (in the polymerization of lactams having at least one a-hydrogen) so that the value of fep in eqn. (74) is not identical with the rate coefficients 2 i o 2 3 (or 2 1 or fe2 3if° , respectively). The decay of amide anions proceeds very rapidly [132, 135] (Fig. 16) and is very sensitive to the ratio [A]o/[I]o-Therefore, all rate equations derived without taking into account the decay of active species or empirical equations like... 

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