Production of magnetically recoverable, thermally stable, bio-based catalyst: Remarkable turnover frequency and reusability in Suzuki coupling reaction

In any catalysis system, regeneration of the used catalyst is of great importance to reduce the cost of industrial applications. However, recovery of the used catalyst from the reaction medium is a difficult task and this can hinder regeneration process. Magnetic separation has emerged as an effective tool to overcome the recovery problem. Hence, in this study a magnetically recoverable sporopollenin-based Pd catalyst has been designed and used in synthesis of biaryl compounds via Suzuki coupling reaction. The thermally stable catalyst exhibited excellent catalytic behaviour without giving any by-products. It is noteworthy that despite their low product yield of aryl chlorides in coupling reactions, remarkable product yields which are comparable to those of aryl bromides and iodides were recorded for aryl chlorides. With very low catalyst loading (1 × 10⁻³ mol%), the catalyst gave TOFs values exceeding one million; i.e., 1.237.500 in very short reaction time. Due to its magnetically separable nature, the catalyst could be recovered from the reaction media easily by increasing the reusability of the catalyst. Even in tenth run biphenyl yield dropped from 99 to 93%.