الفهرس 
chapter 1Only 14 pages are availabe for public view
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Abstract
Three different ionic liquids; 1-methylimidazolium hydrogen sulfate/ FeCl3, 1-butyl-4-methylpyridinium benzoate and 1-octyl-3-methylimidazolium persulfate; were effectively prepared to be used in desulfurization processes of model oil composed of dodecane and dibenzothiophene (DBT) mixture (contains 1000 ppm sulfur content), gasoline and diesel fuels with initial sulfur contents of 500 and 12000 ppm, respectively.
Different characterization tools such as 1H NMR, 13C NMR, FTIR, TGA, Elemental analysis and Raman spectroscopy were used to confirm the structure of the three prepared ionic liquids.
Gasoline and diesel fuels; obtained from Cairo Petroleum Refining Company and El-Nasr Petroleum Company, respectively; were evaluated and used for desulfurization processes by using the three prepared ionic liquids.
1-methylimidazolium hydrogen sulfate/FeCl3; [HMIM][HSO4]/FeCl3; was applied as an effective extractant in extractive desulfurization processes (EDS). High desulfurization ratio (98.1% of DBT-removal) was obtained through EDS of model oil using [HMIM][HSO4]/FeCl3 under moderate reaction conditions (IL/model oil mass ratio of 1/1, reaction temperature of 60oC and reaction time of 60 min). [HMIM][HSO4]/FeCl3 showed an excellent recycling performance where it could be reused seven times with little decrease in desulfurization efficiency (about 1.9% decrease in DBT-removal). A mechanism was proposed for the extractive desulfurization (EDS) process of model oil by using the ionic liquid. [HMIM][HSO4]/FeCl3 could lower the sulfur content of gasoline and diesel fuels down to 36.5 and 144 ppm with 92.7% and 98.8% sulfur removal, respectively through seven multistage EDS under the optimum desulfurization conditions (IL/fuel mass ratio of 1/1, reaction temperature of 60oC and reaction time of 60 min).
1-butyl-4-methylpyridinium benzoate; [BMPy][(C6H5)COO]; was employed in oxidative desulfurization (ODS) process using H2O2. The results showed high desulfurization ability of [BMPy][(C6H5)COO], where 98.9% of DBT was removed from model oil under moderate reaction conditions (oxidant/DBT molar ratio O/S of 8, IL/model oil mass ratio of 1/1, reaction temperature of 60oC and reaction time of 90 min). [BMPy][(C6H5)COO] could be regenerated and recycled five times without a significant loss in desulfurization efficiency (2.4% loss in DBT-removal). A mechanism was proposed for the ODS process of model oil by using the ionic liquid with H2O2. Also, ODS results for gasoline and diesel fuels revealed high efficiency of [BMPy][(C6H5)COO], where it could lower the sulfur content of gasoline and diesel fuels to 31.5 and 72 ppm with 93.7 and 99.4% sulfur removal, respectively through five multistage ODS under desulfurization conditions (O/S molar ratio of 16 and 26 for gasoline and diesel fuels respectively, IL/oil mass ratio of 1/1, reaction temperature of 60oC and reaction time of 90 min).
1-octyl-3-methylimidazolium persulfate; [OMIM][S2O8]; was successfully applied in extractive oxidative desulfurization (EODS) processes where it acted as extractant and oxidant at the same time without the use of an external oxidant like H2O2. [OMIM][S2O8] afforded high desulfurization efficiency as it could eliminate 97.8% of DBT from model oil at adequate reaction conditions (IL/model oil mass ratio of 1/1, reaction temperature of 60oC and reaction time of 90 min). A mechanism was proposed for the EODS process of model oil using BFIL at 25°C. Moreover, [OMIM][S2O8] could lower the sulfur content of gasoline and diesel fuels up to 31 and 49.2 ppm with 93.8% and 99.59% sulfur removal, respectively under desulfurization conditions of (IL/gasoline fuel mass ratio of 1/1, reaction temperature of 60 °C and reaction time of 2.5 h) for gasoline fuel and (IL/diesel fuel mass ratio of 1/1, reaction temperature of 80°C and reaction time of 4.5 h) for diesel fuel.
Therefore, it can be concluded that the three prepared ionic liquids showed high affinity toward the removal of DBT which is considered to be one the most refractory aromatic sulfur compounds hard to be removed. Also, the three ionic liquids could successfully lower the sulfur content of gasoline fuel (500 ppm) to be less than 40 ppm. While in the case of diesel fuel, [OMIM][S2O8] showed the highest desulfurization ability as it could lower the sulfur content of diesel fuel (12000 ppm) to 49.2 ppm, but within long reaction time (4.5 h) and at reaction temperature of 80oC. However, [BMPy][(C6H5)COO] could lower the sulfur content of diesel fuel to 72 ppm, but through five ODS stages. This shows that desulfurization of diesel fuel with excessive sulfur content (12000 ppm) is much harder than that of gasoline fuel with low sulfur content (500 ppm).