Dolomite (CaMg(CO3)2) as a recyclable natural catalyst in Henry, Knoevenagel, and Michael reactions

Iranian dolomite (CaMg(CO3)2) which consists of double-layered carbonates with Ca2+ and Mg2+ ions was utilized as a heterogeneous base catalyst in the CC, CN, and CS bond forming reactions via the Henry, Knoevenagel, aza-Michael, and thia-Michael transformations under mild conditions in water. Iranian dolomite has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer Emmett Teller (BET) and XRF chemical analysis, while its basic strength was evaluated by following the Hammett indicators procedure. This water-insoluble natural catalyst demonstrated high activity and was reusable.

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► Dolomite is a reusable natural catalyst in heterogeneous aqueous reactions.
► Iranian dolomite catalyzes efficiently both condensation and addition reactions.
► Dolomite is a non-toxic catalyst and stable against air and moisture.
► Dolomite is a mild enough base to distinguish between various α-hydrogens.