Polymorph Selection of ROY by Flow-Driven Crystallization

Ziemecka Ziemecka,Gokalp Gokalp,Maes Maes,Stroobants Stroobants,Wit Wit,Brau Brau

doi:10.3390/cryst9070351

Ziemecka Ziemecka, Gokalp Gokalp + Show 4 more

Open Access

https://doi.org/10.3390/cryst9070351

Copy DOI

Abstract

The selection of polymorphs of the organic compound 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile, ROY, is studied experimentally in the confined space between two horizontal glass plates when an acetone solution of ROY of variable concentration is injected at a variable flow rate into water. Depending on the local concentration within the radial flow, a polymorph selection is observed such that red prisms are favored close to the injection center while yellow needles are the preferred polymorph close to the edge of the injected ROY domain. At larger flow rates, a buoyancy-driven instability induces stripes at the outer edge of the displacement pattern, in which specific polymorphs are seen to crystallize. Our results evidence the possibility of a selection of ROY polymorph structures in out-of-equilibrium flow conditions.

Highlights

Crystallization, which is a phase transition from a solution to a highly structured solid form called a crystal, typically occurs via two specific events
We have shown here experimentally that out-of-equilibrium flow conditions can impact the crystallization of polymorphs of the ROY compound
When a solution of ROY is injected into a confined geometry containing water, the phase diagram of polymorphs can unfold

Summary

Introduction

Crystallization, which is a phase transition from a solution to a highly structured solid form called a crystal, typically occurs via two specific events. Atoms or molecules cluster together on a microscopic scale in a process called nucleation. Atoms and compounds can generally form more than one crystal structure. The ability of a molecule to adopt at least two different arrangements in the solid state is called polymorphism [1]. This arrangement of particles is determined during the nucleation stage of crystallization [2,3,4]. We mean the internal arrangement of atoms, ions or molecules in crystal lattices

Objectives

Methods

Results

Conclusion