Green design alternatives for isopropanol recovery in the celecoxib process

Abstract

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 one of their plants was evaluated and several green engineering alternatives for the purification and recovery of isopropanol (IPA) from waste streams proposed. This separation is complex due to the multiple waste streams generated, with varying compositions of IPA, ethanol, methanol, water, and dissolved solids. Overall goals were waste minimization and IPA recovery and purification. A conceptual study of distillation, extraction, reactive distillation, adsorption, and membrane-based processes was performed. Through use of computer simulation and literature/design methodologies, traditional methods were shown to be unable to obtain high IPA purities with the available equipment. Several green design approaches were evaluated using distillation combined with either molecular sieve adsorption or membrane pervaporation. These process schemes appear to have the most promise to effectively recover and purify IPA. The case study describes equipment and processing issues, and estimates environmental impacts from a life cycle analysis.