The kinetics of hydrolytic polymerization of ε‐caprolactam. II. Determination of the kinetic and thermodynamic constants by least‐squares curve fitting

Abstract

Abstract The kinetic and thermodynamic constants of the hydrolytic polymerization of ∂‐caprolactam were determined by least‐squares curve fitting. The calculations were carried out using observed kinetic data such as concentration of ∂‐caprolactam ([CL]), endgroup ([EG]), and ∂‐aminocaproic acid ([ACA]) and time derivatives of each concentration (rates) ∂[CL]/∂ t , ∂[EG]/∂ t , and ∂[ACA]/∂ t . The sets of the converged constants are obtained for the initial water concentrations of 0.42, 0.82, and 1.18 mole/kg. An averaged set of the constants applicable for this range of the initial composition was also evaluated. The compatibility between observed and calculated concentration and rate curves was improved by the use of the newly developed sets of the constants. The mechanism of the polycondensation reaction is also discussed, based on the rate and kinetic constants obtained by this work.