Crystal growth rates of paracetamol in mixtures of water plus acetone plus toluene

• Crystal growth rates of paracetamol (4-hydroxyacetanilide) have been determined by seeded isothermal desupersaturation experiments at 16 degrees C in 23 different solvent mixtures of water + acetone + toluene. Parameters of different growth rate equations have been estimated by direct nonlinear optimization. At equal thermodynamic driving force, the growth rate depends on the composition of the solvent mixture. In the surface diffusion spiral growth model, this dependency can be described in terms of the interfacial energy between the solid and the solution. A reasonable prediction of the influence of the solvent composition on this interfacial energy is obtained if a proper estimation of the enthalpy of dissolution is done. For the case of paracetamol crystals growing in water + acetone + toluene mixtures this estimation needs to include an estimation of the entropy of fusion at the temperature of growth as well as of the nonideal entropy of mixing.

Nyckelord

crystallization

crystal growth

solvents

interfacial energy

puracetamol

chemical potential driving force

structurally related substances

succinic acid crystals

para-hydroxyacetanilide

roughening transition

interfacial-tensions

orthorhombic form

aqueous-solutions

liquid-mixtures

crystallization

solubility

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)