Removal of Benzothiophene Using Butylmethylimidazolium Tetrachloroferrate [BMIM][FeCl4] Ionic Liquid from Dodecane Model Oil

Sulfur compound is the key substance that needs to be separated from model oil. The
conventional sulfur compound removing method is catalytic hydrodesulfurization
(HDS), which requires both a high temperature and high pressure of hydrogen gas to
produce oil having low levels of sulfur compounds. Therefore, the efficiency of HDS is
limited in treating benzothiophene. This project is to develop an advanced
desulfurization process that can be carried out under mild conditions; atmospheric
pressure and room temperature. Extractive desulfurization using [BMIM][FeCl4] ionic
liquid was investigated to remove benzothiophene from dodecane model oil. The
objective is to synthesize [BMIM][FeCl4] ionic liquid and determine its performance in
desulfurization of model oil. Project scope involved mainly four stages; synthesis of the
[BMIM][FeCl4] ionic liquid, characterization of ionic liquid using NMR and FTIR,
extraction of benzothiophene from dodecane model oil, (containing 4% and 6%
benzothiophene) and determination of sulfur removal efficiency using CHNS analyzer.
Two ionic liquids were prepared using anhydrous FeCl3 and hexaydrates FeCl3 reacted
with butylmethylimidazolium chloride. Sulfur removal efficiency of [BMIM][FeCl4]
ionic liquid prepared from anhydrous FeCl3 is 88.6% compared to from hexahydrates
FeCl3 which is 87.9% for 4.0% benzothiophene in dodecane. The ionic liquid
performance decreases as the percentage of sulfur increases.