Active porous ZIF-8 based hybrid catalysts for solvent-free reactions.

Hybrid heterogeneous polymeric catalysts were prepared by distinct methodologies to evaluate their catalytic ability, stability and recycling capacity to promote the ring-opening reaction of styrene oxide with aniline resulting as main product the 2-Amino-1,2-diphenylethanol. These composites were based on porous metal-organic frameworks (MOFs), specifically the zinc-based ZIF-8, activated catalytically by the incorporation of Keggin-type phosphomolybdic acid (PMo12). The resulting composite denoted as PMo12@ZIF-8 was prepared via impregnation and in-situ methods (PMo12 loadings of 0.149 and 0.194 mmol/g were obtained via in-situ and impregnation procedures). Both materials were characterized by FTIR-ATR, PXRD, SEM, EDS, and ICP-OES. The catalytic performance evaluation revealed that both composites exhibited high conversion rates under a sustainable solvent-free system (98% of conversion was achieved after 24 h), and high selectivity toward 2-Amino-1,2-diphenylethanol, along with notable robustness and recyclability.