On-line ATR FTIR measurement of supersaturation during solution crystallization processes. Calibration and applications on three solute/solvent systems

Recently, fourier transform infraRed (FTIR) spectroscopy was reported as a promising technique for in situ measurement of supersaturation during solut ion crystallization processes. The attenuated total reflection (ATR) probes appeared to be particularly suited to the chemical and physical complexity of industrial suspensions. However. to be used in an industrial contest, t he technique must be easily and quickly adaptable to different systems. In order to achieve such an aim, a calibration procedure to monitor supersatur ation from FTIR measurements is presented. General comments and recommendat ions about important technical aspects of the technique are also given. The n the technique is used to develop efficient procedures for the determinati on of solubility: and metastability curves. The crystallization of three li ne chemical products is studied, thanks to on-line FTIR measurements of sup ersaturation and off-line CSD determinations. It is shown that the monitori ng of supersaturation is a valuable tool for an improved analysis of key ph enomena involved during crystallization processes (primary and secondary nu cleation. agglomeration, phase transition, seeding, etc.). (C) 2001 Elsevie r Science Ltd. All rights reserved.