Three column intermittent simulated moving bed chromatography: 3. Cascade operation for center-cut separations

Area of Science:

• Chromatography
• Chemical Engineering
• Separation Science

Background:

• Simulated Moving Bed (SMB) chromatography is a powerful technique for continuous separation.
• Designing SMB cascades, especially for multi-component mixtures, requires robust methodologies.
• Purification of stereoisomers, like nadolol, presents significant separation challenges.

Purpose of the Study:

• To propose and validate a general design methodology for three-column intermittent simulated moving bed (3C-ISMB) cascades.
• To optimize the purification of nadolol stereoisomers using the 3C-ISMB cascade.
• To develop a re-scaling approach for the second stage of the cascade to improve efficiency.

Main Methods:

• Theoretical design using Triangle Theory for the 3C-ISMB cascade.
• Experimental determination of linear adsorption and multi-component Langmuir isotherms for nadolol stereoisomers.
• Frontal analysis and cascade experiments to validate the design methodology and optimize separation conditions.

Main Results:

• The 3C-ISMB cascade design methodology was successfully validated experimentally.
• A re-scaling approach for the second stage improved operational conditions and efficiency.
• Optimal conditions yielded a productivity of 2.10 g/L/h and 97.8% product purity with reduced solvent consumption.

Conclusions:

• The proposed 3C-ISMB cascade design methodology is effective for complex chromatographic separations.
• The re-scaling approach enhances the adaptability and performance of multi-stage SMB processes.
• This method offers a promising solution for efficient purification of stereoisomers and other challenging mixtures.