Spherical crystallization of benzoic acid

This paper deals with the development of a method for spherical crystallization of benzoic acid. Benzoic acid is dissolved in ethanol, water is used as anti-solvent and chloroform is used as bridging liquid. After an introductory screening of different methods, the influence of the amount of the bridging liquid, the solute concentration and the stirring rate is investigated. The product particle characterization includes the particle size distribution, morphology and strength. The mechanical strength of single agglomerates has been determined by compression in a materials testing machine, using a 10 N load cell. It is found that favourable properties are obtained if the bridging liquid is added during the crystallization. Larger and stronger well-shaped agglomerates are formed. The stress-strain curves are J-shaped with no clear fracturing of the particles, and are well correlated by an exponential-polynomial equation. (c) 2007 Elsevier B.V. All rights reserved.