Catalysed oxidation of quinoline in model fuel and the selective extraction of quinoline-N-oxide with imidazoline-based ionic liquids

Synthesised vanadium-coordinated N,N-bis(o-hydroxybenzaldehyde)phenylene diamine catalyst, [VO(sal-HBPD)] and supported catalyst, p[VO(sal-HBPD)] were employed for the oxidation of quinoline. The use of [VO(sal-HBPD)] and p[VO(sal-HBPD)] for the oxidation of quinoline, (Quinoline-to-H2O2 ratio 1:7) showed oxidation selectivity as quinoline-N-oxide (100%) was recorded as the oxidation product. Quinoline-N-oxide was confirmed as the oxidation product through GC-MS. Density functional theory (DFT) revealed hydroxylperoxido-species [VOO(sal-HBPD)] (II) as the reactive oxidized oxidovanadium specie responsible for the oxidation. Ionic liquids, 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium nitrate extracted 96% and 87% quinoline-N-oxide respectively.