Hydrophobic Polymer-Supported Lewis Acid for Solid-Phase Synthesis

Abstract

Conventional unsupported Lewis acids are more sensitive towards moisture rather than substrate resulting into deactivation of the catalyst and difficult to use in an anhydrous reaction. In the present work, deactivation of the conventional Lewis acids was strongly avoided by using hydrophobic polymer-supported Lewis acids (PSLAs). The obtained PSLAs were characterized by different techniques including surface area, particle size, thermostability, glass transition temperature, and morphology. Surface areas of PSLAs were in the range of 50-80 m 2 /g whereas particle sizes of polymer beads were in the range of 15-35 μm before and after polymer modification. Further, degradation of base polymer and PSLAs were in the range of 440-450 o C whereas glass transition temperature (T g ) of base polymer was upto 400 o C. However, T g was attenuated for polymer containing AlCl 3 and further for HgCl 2 . Importantly, leakage problem of the Lewis acids was eliminated due to strong co-ordinate bonding between polymer and catalyst.