Novel iota carrageenan-based RhCl₃ as an efficient and recyclable catalyst in Suzuki cross coupling

RhCl₃ was heterogenized into renewable polysaccharide supports, and the effect of polysaccharide type on the new catalyst performances in a Suzuki cross-coupling reaction was studied. The conversion of the fresh iota carrageenan heterogeneous system (ἰ-RhCl₃), was found to be the highest, whereas it was lower than the conversion of its homogeneous analogue. In addition, the ἰ-RhCl3 (catalyst loading of 6.5 % wt) was proven to be efficient heterogeneous catalyst that was easily recycled, whereas the conversion was increased in the first and second cycles. Scanning electronic microscopy (SEM) combining Energy dispersive X-ray spectrometry and Surface analysis by X-ray photoelectron spectroscopy were performed, confirming that RhCl₃ was embedded within the ἰ-carrageenan. The Fourier-transform infrared spectrometry of the heterogeneous ἰ-RhCl₃ catalyst was compared to that of the native polysaccharide, and no new bands were detected. Nonetheless, a comparison of SEM image of ἰ-carrageenan with and without RhCl₃, as well as rheological measurements of the aqueous solution of ἰ with and without RhCl₃, indicated the incorporation of the polysaccharide with the RhCl₃.