The Effect of Solvents on the Crystal Morphology of Pyriproxyfen

Abstract

To obtain crystal products with ideal morphology and better quality, it is important to fully understand and grasp the affecting mechanism of solvents on crystal morphology. In this work, the interactions between solvent/solute molecules and different crystal faces of pyriproxyfen are investigated by a combination of experiments and molecular simulations. It is found that pyriproxyfen crystals grow into a lamellar morphology in methanol and ethanol, while the crystal grows into a three-dimensional shuttle morphology in n-butanol and n-heptane. Molecular simulations reveal that the molecular arrangement of crystal faces makes the alcohol hydroxyl adsorption sites exposed in different degrees, and the (002) face is more sensitive to alcohol hydroxyl than other faces. The adsorption of alcohol hydroxyl groups hinders the growth of crystal planes, so (002) and (102) faces become the main crystal planes in methanol and ethanol, and the lamellar crystal is formed. The developed knowledge of the growth mechanism based on the interaction between the solvent and crystal interface can be conducive to the further optimization of the pyriproxyfen crystal products.

The Effect of Solvents on the Crystal Morphology of Isosorbide Mononitrate and Its Molecular Mechanisms

“…The crystal morphology of ISMN is needle-like, with poor fluidity and low packing density, which brings inconvenience to the subsequent process treatment process [ 12 ]. After chemical synthesis of ISMN, the product is purified and refined by solution crystallization [ 13 ], and in the process of solution crystallization, different solvents have a large effect on the crystal morphology due to the different sensitivity of crystal faces to solvents [ 14 ]. The study of the molecular mechanism of ISMN crystal habit manipulation is important for improving the crystallization process and enhancing product properties.…”