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Near-infrared (NIR) spectroscopy is proposed for the in-line quantitative and kinetic study of the polymerization of epsilon-caprolactone and eventually to facilitate real-time control of the manufacturing process. Spectra were acquired with a fibre-optic probe operating in transflectance mode immersed in the reactor. The NIR data acquired were processed using a multivariate curve resolution alternating least squares (MCR-ALS) algorithm. The proposed method allows calculation of the concentration and spectral profiles of the species involved in the reaction. The key point of this method is the lack of reference concentrations needed to perform the MCR-ALS method. The use of an extended spectral matrix using both process and pure analyte spectra solves the rank deficiency. The concentration profiles obtained were used to calculate a kinetic fitting of the reaction, but the method was improved by applying kinetic constraints (hard modelling). The rate constants of batches at different temperatures and the energy of activation for this reaction were calculated. Whenever possible, the hard modelling combined with the MCR-ALS method improves the fit of the experimental data: the results show good correlation between the NIR and reference data and allow the collection of high-quality kinetic information on the reaction (rate constants and energy of activation).

hydrogen peroxide. This active agent has the disadvantage that it becomes unstable with time, which necessitates the use of various additives in the formulation to ensure its stability. In this work, a study of the different types of surfactants, chelating agents, radical scavengers, stabilizers, and solvents, commonly used in the bleaching industry, was made to identify the mixture that better stabilizes an aqueous solution of hydrogen peroxide.The strategy used starts with a screening step based on a hyper-Greco-Latin square design. In subsequent steps, a BoxWilson design is used to construct a response surface model to identify the composition ensuring the highest possible stability in the formulation. A desirability function is then obtained that allows the stability of the formulation to be maximized and its cost simultaneously minimized. Such a function is optimized using the Nelder-Mead algorithm.The stability study was made by heating the mixtures at 60°C for variable periods of time. A mixture containing four of these additives was found to provide the best stability, and the solvent did not have any effect on the stabilization. However, this mixture exceeded the expectations in terms of cost, so the composition was adjusted to obtain the best compromise between stability and cost. As the stabilizer is the more expensive additive, in this optimization step its composition was reduced. In the final formulation, the stabilizer concentration can be reduced by up to 23% with respect to that obtained in the previous step without detracting from stability, thereby saving 18.8%.Paper no. S1533 in JSD 9, 341-347 (Qtr. 4, 2006). 9KEY WORDS: Bleaching formulation, Box-Wilson design, desirability function, experimental design, hydrogen peroxide, Nelder-Mead algorithm.Hydrogen peroxide is a widely used textile bleaching agent that is considered toxicologically and environmentally acceptable, as its decomposition products (oxygen and water) are harmless (1). However, aqueous solutions of peroxides are unstable, so their activity and bleaching capacity decrease with time. This is especially true of formulations containing hydrogen peroxide, particularly in alkaline media, where their bleaching activity is especially high (2). The instability results from photochemical reactions that facilitate the formation of radicals and from the presence of traces of Fe, Cu, and other cations of heavy metals that catalyze the decomposition of peroxides (3).The aim of this work was to optimize the composition of a -bleaching detergent formulation based on an alkaline aqueous solution of hydrogen peroxide. Its ingredients should either take part in the bleaching process or help stabilize the bleach (hydrogen peroxide).In order to stabilize the hydrogen peroxide, the formulation included a chelating agent intended to sequester metals that could catalyze the peroxide decomposition reaction (4) and a radical scavenger to suppress any radicals formed in the medium. Also, it included a surfactant intended to increase the detergent power (...