Analysis of separation methods for isopropanol recovery in the celecoxib process

Various approaches to solvent recovery have been studied for the manufacturing process of celecoxib, the active ingredient in Celebrex®. A design case study has been performed by Rowan University with Pfizer through a green engineering partnership program. The manufacturing operation at Barceloneta, Puerto Rico was evaluated and several green engineering alternatives for the purification and recovery of isopropanol from waste streams proposed. This separation is complex due to the multiple waste streams generated, with varying compositions of isopropanol, ethanol, methanol, water and dissolved solids. Overall goals were waste minimization and isopropanol recovery and purification. The group performed a conceptual study of distillation, extraction, reactive distillation, adsorption, and membrane-based processes. Through use of computer simulation and literature/design methodologies, traditional methods were shown to be unable to obtain high isopropanol purities with the equipment available. Both molecular sieve adsorption and membrane pervaporation appear to have the most promise to effectively recover and purify isopropanol. Several green design approaches were evaluated using distillation combined with either molecular sieve adsorption or membrane pervaporation. The case study describes equipment and processing issues, and estimates environmental impacts and costs.