Crystallization of paracetamol in acetone-water mixtures

摘要

The influence of solvent compositon on the crystallization of paracetamol (4-hydroxyacetanilide) in acetone-water mixtures is investigated. Particle generation and crystal growth kinetics have been studied by batch isothermal desupersaturation experiments at constant solvent composition. The solubiltiy exhibits a very pronounced maximum at approximately 20 wt/100 wate. Nucleation and agglomeration increase with increasing initial supersaturation, but at a given initial supersaturation, the solvent compostion has no clear influence on the product particle characteristics. The crystal growth rate is hgiher in pure acetone than in pure water, but hte rate passes through a maximum in a mixture containing 20-25 wt /100 water. There is good correlation between crystal grwoth rate and solubiltiy, even through the growth rate is comparativley high at hgih water concentrations.