Estimation of the growth kinetics for the cooling crystallisation of paracetamol and ethanol solutions

Niall A. Mitchell, Clifford T. Óciardhá, Patrick J. Frawley

Research output: Contribution to journalArticlepeer-review

Abstract

This work details the estimation of the growth kinetics of paracetamol in ethanol solutions for cooling crystallisation processes, by means of isothermal seeded batch experiments. The growth kinetics of paracetamol crystals were evaluated in isolation, with the growth rate assumed to be size independent. Prior knowledge of the Metastable Zone Width (MSZW) was required, so that supersaturation ratios of 1.71.1 could be induced in solution without the occurrence of nucleation. The technique involved the utilisation of two in-situ Process Analytical Techniques (PATs), with a Focused Beam Reflectance Measurement (FBRM®) utilised to ensure that negligible nucleation occurred and an Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) probe employed for online monitoring of solute concentration. Initial Particle Size Distributions (PSDs) were used in conjunction with desupersaturation profiles to determine the growth rate as a function of temperature and supersaturation. Furthermore, the effects of seed loading and size on the crystal growth rate were investigated. A numerical model, incorporating the population balance equation and the method of moments, was utilised to describe the crystal growth process. Experimental parameters were compared to the model simulation, with the accuracy of the model validated by means of the final product PSDs and solute concentration.

Original languageEnglish
Pages (from-to)39-49
Number of pages11
JournalJournal of Crystal Growth
Volume328
Issue number1
DOIs
Publication statusPublished - 1 Aug 2011

Keywords

  • A1. Computer simulation
  • A1. Crystallisation
  • A1. Growth
  • A1. Kinetics
  • A1. Seeded batch
  • B1. Paracetamol

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