Green Synthesis of Pharmaceutical Polymers Using Heterogeneous Phase-Transfer Catalysis

The development of environmentally sustainable synthetic methodologies has become increasingly important in pharmaceutical and polymer research. Phase-transfer catalysis (PTC) provides an efficient approach for facilitating reactions between reagents present in different phases and can improve reaction efficiency under heterogeneous conditions. In the present study, tetra-isopropylammonium chloride (PTC) was synthesized as a phase-transfer catalyst using ammonia and isopropyl chloride in ethanol under reflux conditions. The synthesized catalyst was purified by repeated ether washing and characterized using Fourier-transform infrared (FT-IR). The catalytic performance of PTC was investigated in the polymerization of styrene using an aqueous/organic biphasic system. Polymerization experiments were performed at different styrene concentrations and temperatures, both in the presence and absence of PTC. The reported results demonstrated an increase in the rate of polymerization with increasing monomer concentration. At 65 °C, the reported polymerization rate increased from 0.087 to 0.308 without PTC and from 0.125 to 0.438 in the presence of 0.5 g PTC as the styrene volume increased from 2 to 7 mL. At 75 °C, the corresponding rate increased from 0.149 to 0.519 in the presence of PTC. These findings indicate that PTC enhances the polymerization process under the investigated heterogeneous conditions. The resulting polymeric materials may have potential relevance to polymer-based pharmaceutical technologies, particularly controlled drug-delivery systems; however, direct drug loading, encapsulation, release, biocompatibility, and therapeutic studies were not included in the present investigation. Thus, the study provides a foundation for further development of PTC-assisted polymeric materials for potential drug-delivery applications.

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