Multiphase extraction

Before leaving ionic liquids it is worth mentioning their potential value in separation processes. Organic solvents are frequently used in multiphase extraction processes and pose the same problems in terms of VOC containment and recovery as they do in syntheses, hence ionic liquids could offer a more benign alternative. Interesting applications along this line which have been studied include separation of spent nuclear fuel from other nuclear waste and extraction of the antibiotic erythromycin-A. 

Multiphase extraction uses a vacuum system to remove various combinations of contaminated groundwater, separate-phase petroleum product, and vapors from the subsurface. The system lowers the water table around the well, exposing more of the formation. Contaminants in the newly exposed vadose zone are then accessible to vapor extraction. Once above ground, the extracted vapors or liquid-phase organics and groundwater are separated and treated. 

J.L. Lopez and S.L. Matson, A Multiphase/Extractive Enzyme Membrane Reactor for Production of Diltiazem Chiral Intermediate, J. Membr. Sci. 125, 189 (1997). 

Membrane bioreactors have been reported for the production of diltiazem chiral intermediate with a multiphase/extractive enzyme membrane reactor [15, 16]. The reaction was carried out in a two-separate phase reactor. Here, the membrane had the double role of confining the enzyme and keeping the two phases in contact while maintaining them in two different compartments. This is the case of the multiphase/ extractive membrane reactor developed on a productive scale for the production of a chiral intermediate of diltiazem ((2R,3S)-methylmethoxyphenylglycidate), a drug used in the treatment of hypertension and angina [15]. The principle is illustrated in... 

Lopez, J.L. and Matson, S.L. (1997) A multiphase/extractive enzyme membrane reactor for production of diltiazem chiral intermediate. Journal of Membrane Science, 125, 189. 

The results obtained with the reported extraction model showed that the separation of charged species is possible, provided a suitable ligand hydrophobicity. Further analytical developments of these multiphase extraction systems will require an accurate investigation of the equilibria and kinetic processes occurring at the interfaces, as well as the study of the micellar structure and properties of the host aggregates. 

When producing high value biochemicals, the economic analysis is, generally, more favorable for the MBR systems, when compared with the more conventional units. Often selectivity rather than conversion may be the key, since higher selectivities typically result in the elimination of some of the purification steps which have a strong influence on the total production costs. The application of the multiphase/extractive enzyme membrane reactor for the production of a diltiazem chiral intermediate was reported in Chapter 4... 

In addition to the enzymatic fat splitting and esterifications, a multiphase extractive enzyme membrane reactor is being used for the industrial production of a diltiazem chiral intermediate. This process will be described in more detail in Section 5.3.5. 

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