Amino-functionalized SBA-15 immobilized NiBr2(PPh3)2 as a highly effective catalyst for ATRP of MMA

Abstract: 3-Aminopropyltriethoxysilane modified mesoporous SBA-15 was used to load the NiBr2(PPh3)2 as a heterogeneous catalyst for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) when initiated by ethyl 2-bromoisobutyrate (EBriB) in toluene. Due to the Lewis acid sites formed by the surface silanol groups of the mesoporous material, some monomer conversions were much higher even than that catalyzed by the homogeneous catalyst NiBr2(PPh3)2 under the same reaction conditions while polydispersity indices (PDI) of the products still kept narrow (1.20–1.30). At the same time, the activity of the catalyst could be modulated by changing the quantity of the –NH2, SBA-15 and the free PPh3. In the recycling experiments, the recovered heterogeneous catalyst basically maintained its catalytic activity without any addition of new heterogeneous catalyst. [ABSTRACT FROM AUTHOR]