| Description: |
Antisolvent crystallization is extensively used to form organic compounds, especially to purify reactions. This operation requires exhausting downstream processing to fine-tune crystal properties. Instead, membranes could be used to produce in one step a narrow crystal size distribution (CSD) saving raw material, and energy. This work investigated the role of membrane-assisted antisolvent crystallization (MAAC) in shifting forward the reaction equilibrium while controlling crystal formation. MAAC encompasses the membrane's ability to both control antisolvent mass transfer and provide high mixing, which correlates directly with the supersaturation rate. The optimized operation of MAAC is reflected in the stability of the mass transfer coefficient to ensure no membrane wetting by the crystallizing solution and controlled transport of the antisolvent. A specific combination of the operating condition, such as flow rate, antisolvent composition, temperature, or gravity resistance plays a key role in tailoring the induction times. Besides, fine-tuning the properties of the membrane, such as its porosity, thickness, and hydrophobicity is advantageous to control crystal formation. The thinner the membrane, the more hydrophobic or the more porous it was, the higher the antisolvent transmembrane flux, the lower the induction time, and the smaller the resulting crystals. This work demonstrated that indeed MAAC is capable of intensifying crystallization processes by providing a one-step narrow CSD, up to four times better than batch or drop-by-drop crystallization, and helping purify challenging reactions for the development of organic compounds. |