Binuclear Dioxomolybdenum(VI) Complex Based on Bis(2-pyridinecarboxamide) Ligand as Effective Catalyst for Fuel Desulfurization

A binuclear dioxomolybdenum catalyst [(MoO2Cl2)2(L)] (1) (with L (1S,2S)-N,N′-bis(2-pyridinecarboxamide)-1,2-cyclohexane) was prepared and used as catalyst for the desulfurization of a multicomponent model fuel containing the most refractory sulfur compounds in real fuels. This complex was shown to have a high efficiency to oxidize the aromatic benzothiophene derivative compounds present in fuels, mainly using a biphasic 1:1 model fuel/MeOH system. This process conciliates catalytic oxidative and extractive desulfurization, resulting in the oxidation of the sulfur compounds in the polar organic solvent. The oxidative catalytic performance of (1) was shown to be influenced by the presence of water in the system. Using 50% aq. H2O2, it was possible to reuse the catalyst and the extraction solvent, MeOH, during ten consecutive cycles without loss of desulfurization efficiency.