Ultra‐Deep Desulfurization of Diesel: Oxidation with a Recoverable Catalyst Assembled in Emulsion

Abstract

A [(C(18)H(37))(2)N(+)(CH(3))(2)](3)[PW(12)O(40)] catalyst, assembled in an emulsion in diesel, can selectively oxidize the sulfur-containing molecules present in diesel into their corresponding sulfones by using H(2)O(2) as the oxidant under mild conditions. The sulfones can be readily separated from the diesel using an extractant, and the sulfur level of the desulfurized diesel can be lowered from about 500 ppm to 0.1 ppm without changing the properties of the diesel. The catalyst demonstrates high performance (>/=96 % efficiency of H(2)O(2), is easily recycled, and approximately 100 % selectivity to sulfones). Metastable emulsion droplets (water in oil) act like a homogeneous catalyst and are formed when the catalyst (as the surfactant) and H(2)O(2) (30 %) are mixed in the diesel. However, the catalyst can be separated from the diesel after demulsification.

Catalytic oxidation of thiophene and its derivatives via dual activation for ultra-deep desulfurization of fuels

“…Therefore, the catalytic system we developed has a broad substrate scope in aromatic sulfur-containing compounds. 4 , the conversion of BT is only 49% at 60°C and less than 5% at 20°C (Fig. 2b).…”

“…All potentials were estimated using a saturated calomel electrode (SCE) as the reference electrode and the scan rate of the potential was 4 mV s À1 . The remained sulfur-containing compounds in model oil after oxidation were analyzed by GC-SCD (sulfur chemiluminescence detection) (GC: Agilent 7890A equipped with a capillary 4 , and 4 mol% catalyst in 50 mL vessel was stirred vigorously at 60°C. After the reaction, the sulfur content of the model oil phase was analyzed directly by GC-SCD or Antek 9000S total sulfur analyzer.…”

“…In the extraction coupled with catalytic oxidation process, commercial ammonium tungstate was selected as catalyst. When [Bmim]BF 4 was used as an extractant to remove thiophene from model oil, the desulfurization efficiency is poor (the removal of thiophene is only 15.3% 4 . This indicates that these BAILs play an important role in catalytic oxidation of thiophene.…”

“…A white precipitate appeared immediately. After washed with an excess of H 2 O and dried, the XRD pattern of the precipitate is attributed to BaSO 4 (Fig. 4a).…”

“…More recently, a new and effective approach that is chemical oxidation in conjunction with ILs extraction (ECODS) has been explored in order to improve the efficiency of desulfurization [3]. However, to date, the efficiency of ECODS system for FCC gasoline is still low [4][5][6][7][8][9][10][11][12][13][14], because the major sulfur-containing compounds of FCC gasoline, thiophene, and its derivatives are difficult to be oxidized [15].…”