Adsorptive separations of chiral enantiomer pairs, or "racemicmixtures", are a critical problem of the pharmaceutical and fine chemical industries. In this project, a new functional group approach to investigate sorbent-solutesolvent interactions will be used for a major class of chiral sorbents, derivatized amylose and cellulose. These sorbents are used in over 50% of all analytical and preparative adsorptive chiral separations. A series of simple non-chiral solutes with one or two hydrogen bonding (Hbonding) functional groups and hydrophobic functional groups are studied using elution chromatography, to identify the key functional groups that contribute to solute retention times in various solvents and their relative importance. IR studies are used to identify the H-bonding sites of the key functional groups of the solutes, the solvents, and the sorbents.
Understanding the specific interactions of the individual functional groups will be used to interpret the retention behavior and chiral selectivities of solutes with two or more functional groups in different solvents and at different temperatures. A practical predictive model wil be developed for selection of solvent and sorbent for a separation of a given chiral solute using this class of CSPs. This analysis using a combination of chromatography studies, direct probing techniques, and molecular simulations is scientifically unique. The results should generate general guidelines for selecting solvents, sorbents, and temperatures to optimize retention times, selectivities, productivity, and solvent consumption in chiral chromatography for both analytical separation applications and large-scale production of single enantiomers. The functional group studies can be applied to advance understanding of retention times and selectivities in other types of chromatography. Improved scientific understanding of the interactions of the specific functional groups and chiral recognition at the molecular level has applications in many other areas, such as sensors, biomaterials, drug design, and nanotechnology. The broader impacts will be in the area critical to healthcare. Chiral separations are crucial for producing safe and affordable enantiomer drugs. The research will improve the teaching and training of graduate and undergraduate students and may lead to further fundamental research and innovative materials and processes. The project will help train advanced-level chemical engineers specializing in an important technology area. Some of these engineers will be recruited from underrepresented groups. The research will benefit four graduate and undergraduate courses, Separations, Interfacial Engineering, Thermodynamics, and Reaction Engineering. The project will also help enhance the competitiveness of the US industry and of the US universities in an important area of advanced technology.
