[HDMF]Cl-based DES as highly efficient extractants and catalysts for oxidative desulfurization of model oil

N,N-Dimethylformamide hydrochloric acid/XMCln ([HDMF]Cl/XMCln, M = Zn or Fe, n = 2 or 3) was synthesized by stirring the mixture of [HDMF]Cl and metal chloride. [HDMF]Cl-based DES was characterized by FT-IR spectroscopy, ESI-MS and 1H-NMR spectroscopy. The oxidative desulfurization activity was investigated using [HDMF]Cl/0.2FeCl3 and [HDMF]Cl/ZnCl2 as the extractant and catalyst, and hydrogen peroxide (H2O2) as the oxidant. The desulfurization rate can reach up to 98.08% and 99.2% for DBT using [HDMF]Cl/0.2FeCl3 and [HDMF]Cl/ZnCl2, respectively. After recycling for 7 times, the removal rate of DBT still can reach more than 97%.