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Solubility and nucleation in l(+)-ascorbic acid–methanol–ethanol–water system

2006; Elsevier BV; Volume: 46; Issue: 4 Linguagem: Inglês

10.1016/j.cep.2006.07.005

1873-3204

B. Wierzbowska, A. Matynia, K. Piotrowski, J. Koralewska,

Freezing and Crystallization Processes

The experimental data concerning the practical solubility, metastable zone width and nucleation kinetics in l(+)-ascorbic acid–methanol–ethanol–water system are presented. Measurements were performed in a laboratory cooled batch crystallizer with internal circulation of suspension. Practical solubility of l(+)-ascorbic acid in water solutions with addition of both methanol and ethanol was determined using the last crystal dissolution method within the temperature range of T = 313–353 K. Influence of solution composition and its cooling rate on the value of maximal supercooling of the system is presented and discussed. Nucleation kinetics was elaborated with the use of Kubota's model of stochastic nucleation in the initial seeding system. Parameter values in the kinetic equations were determined with the method of maximal (critical) supercooling of the solution (constant cooling rates from RT = 4.17 × 10−3–33.3 × 10−3 K s−1 range were applied).