In this study, a series of metal complex DESs based choline chloride (MCDESs) with different metal chlorides including FeCl3, FeCl2, CuCl2, SnCl2 and ZnCl2 using 1,3-Diphenylguanidine and 1,5-Diphenylcarbazide as
complexing agents were synthesized and their efficiencies for extractive desulphurisation were considered. FTIR technique was used for characterization of the synthetized MCDESs. The influential parameters including temperature, time, type of MCDESs, and the mass ratio of MCDESs to model fuel were investigated. Sndiphenylcarbazide based choline chloride DES had the best potential for the extraction of dibenzothiophene,
thiophene, and 3-methylthiophene from n-octane as model fuel. At optimum conditions of time 10 min, temperature 35 °C, and MCDESs to model fuel mass ratio 1:25 the highest desulphurisation (%) of 95.2 ± 0.3, 94.5 ± 0.5,
92.1 ± 0.6 were achieved for dibenzothiophene, 3-methylthiophene, and thiophene respectively after one cycle
of extraction which indicated high capability of the synthesized MCDESs for extractive desulphurisation through
π-complexation. and π-π interaction with the target thiophenic compounds. Moreover, the used MCDES was successfully regenerated and efficiently reused in desulphurisation process which confirmed the industrial potential
of the synthetized MCDESs