Ian David Lockhart Bogle and Michael Fairweather (Editors), Proceedings of the 22nd European Symposium on Computer Aided Process Engineering, 17 - 20 June 2012, London. © 2012 Elsevier B.V. All rights reserved. Estimation of Kinetic Parameters and Mathematic Model Validation for Nylon-6 Process Vanessa I. Funai, a Delba N. C. Melo, a Nádson M. N. Lima, a Ana F. Pattaro, a Lamia Zuñiga Liñan, a Anderson J. Bonon, a Rubens Maciel Filho a a Laboratory of Opmization, Design and Advanced Control - LOPCA, School of Chemical Engineering, State University of Campinas – Unicamp, Av. Albert Einstein, 500, Campinas – SP, 13083-852 , Brasil Abstract This work presents the simulation of the hydrolytic polymerization process of nylon-6 in a lab-scale semi-batch reactor, using ε-caprolactam as monomer and acetic acid as monofunctional acid chain terminator. The kinetic scheme comprises 6 reactions: 3 main reactions, 2 side reactions associated with the cyclic dimer formation and one monofunctional acid termination. Operating conditions were obtained from previous definitions and kinetic parameters were estimated from experimental data. The proposed optimization problem to estimate the kinetic parameters was solved by the Successive Quadratic Programming (SQP), a deterministic method. It was shown that the method is able to determine the final solution with good precision. The validity of the model was confirmed by comparison of the results obtained by computer simulation using the software Aspen Polymer Plus ® and the process real data. Keywords: optimization, simulation, polymerization, poliamide-6. 1. Introduction Nylon is considered the first polymer in the category of engineering plastics and still remains as one of the most important since its discovery in 1935. The commercial relevance of Nylon-6 is widely known. In order to have a final product with desired properties it is necessary to have a better comprehension of the polymerization process including the reactor performance. Since plant experiments are time consuming and expensive, simulations are important means to study the process. However, the results of the simulator should be faithful to those obtained by the real process. To ensure this, it is necessary the validation of the results, performed by a comparison between the real and the simulated process outputs, which should be similar. One way to validate the simulator is estimating the reaction parameters. Optimization methods have been widely used to determine kinetic parameters (Mansoornejad et al., 2007). The objective of this work is to simulate and to estimate the most significant kinetic parameters of the hydrolytic polymerization of nylon-6 in order to validate a mathematic model based on a nylon-6 polymerization reactor operated on semi-batch mode used for polymer research at Biofabris Institute/State University of Campinas/Brazil. The estimation of the parameters was performed by the use of the Sequential quadratic programming method (SQP). Simplified predictive models of average molecular weight (MWN) and monomer conversion (X CL ) were used to formulate the objective function of the problem.