CTS-9729404 Hatton, T.A. MIT Abstract It is proposed to develop a new class of solvents that have solvation properties similar to those of solvents used conventionally in pharmaceutical and fine chemical processing but for which the potential for loss by environmentally-unfavorable air emissions or in aqueous discharge streams is minimized. A complete characterization of the new solvent is to be undertaken, and their role in minimizing the potential for pollution, and in reducing the number of solvent exchanges and unit operations required for specific processes will be evaluated. The economic and environmental impact assessment will include al aspects of the solvent usage, including its synthesis and any wastes that may be generated thereby. These new solvents will be obtained by suitable derivatization of the solvent tetrahydrofuran (THF) to be replaced to render it significantly less volatile or water soluble, and thus less inclined to enter the environment; the active solvent moiety will also be 'immobilized' by attachment to flexible polymers, which are then dissolved in a more benign continuous phase. These new solvents will be tested as reaction media for a broad range of model reaction systems, including a series of reactions that are important in the production of the HIV protease inhibitor Crixivan Detailed spectroscopic characterization as well as bulk thermodynamic properties will be used to rationalize the kinetics results in terms of steric and electronic effects introduced by the solvent modification. Process systems modeling will be carried out to quantify the economic and environmental impact of processes using these solvents, and compared with conventional systems. A new range of solvents will be developed and characterized in terms of their solvation, thermodynamic and transport properties, and tested for their efficacy as reaction media using a range of different model reactions. Guidelines will be established for product recovery and solvent regeneration, and process systems models will be developed for optimization of reaction/separation sequences in pharmaceutical and fine chemical syntheses. A life cycle analysis of these new solvents from synthesis through to use in processing, including solvent regeneration, will be made to delineate their useful application parameters.
