NMP center dot FeCI3 (NMP = N-methyl-2-pyrrolidone, C5H9NO) ionic liquid (IL) was effectively immobilized on gamma-Al2O3 as a support and examined in the catalytic oxidative deep desulfurization (ODS) of BT, DBT and 4,6-DMDBT from model oil employing 30 wt.% H2O2 as the oxidant reagent. The supported catalyst was prepared via a simple wet impregnation and the effective immobilization of IL was confirmed by FTIR, SEM, EDS, XRD, BET and BJH analysis. The maximum efficiency of 99% was achieved for ODS of DBT using supported IL at the loading amount of 10 wt.%, H2O2/sulfur molar ratio of 4, temperature of 40 degrees C, and duration of 90 min. The use of support material in this study resulted in using a lower amount of IL in ODS process. The ODS reactivity of the thiophenic compounds changed in the order of DBT > 4,6-DMDBT BT. The catalyst was recycled for several times and showed no significant loss in the activity. Furthermore, based on GC-MS analysis of the products, desulfurization mechanism was surveyed and a reasonable pathway was proposed. (C) 2017 Elsevier B.V. All rights reserved.