Regioselective ROH-epoxystyrene-opening over MWCNTs-[N4] macrocycle comprising Cu(II), Fe(III) or Cr(III)

Abstract

By considering the importance of heterogeneous catalysts with separation and recycling ability from the reaction environment and ring opening of epoxide as a regularly essential conversion in organic synthesis, tetraaza macrocyclic complexes of Cu(П), Fe(IП) and Cr(Ш) were grafted on the acylated multiwalled carbon nanotubes (MWCNTs) to produce new nanocomposites as heterogeneous catalysts. Then the nanocomposites were applied in the regioselective ring-opening reaction of epoxystyrene with different alcohols to obtain β-alkoxy compounds. For the characterization of tetraazamacrocycle and nanocomposites, FT-IR, TGA, XRD, FE-SEM and Raman were employed. Results showed that the complexes were successfully grafted on the functionalized MWCNTs. Ring-opening reactions took place at high yield and favorite time, especially for the shorter chain alcohols. In the best case, nanocomposite containing Fe(Ш) (MWCNTs-C (=O)–TAM·Fe^III) accomplished the ring opening of epoxystyrene by methanol (100%) within 15 min at 50 °C, and after 3 recycling test, there are negligible changes in its catalytic performance.