Removal of Benzothiophene by Extraction with Deep Eutectic Solvents[Bmim]Br-Polyalcohol

Deep eutectic solvents(DESs)1-butyl-3-methylimidazolium bromide-polyalcohol([Bmim]Br-polyalcohol)were synthesized from[Bmim]Br and polyalcohol such as ethylene glycol(EG),propylene glycol(PG),glycerol(GL)at a molar ratio of 1:2.[Bmim]Br-2propylene glycol([Bmim]Br-2PG)was characterized with FT-IR spectroscopy and 1H NMR.The removal of benzothiophene(BT)from model oil was investigated by extraction with DES[Bmim]Br-2PG.The results showed that an extraction efficiency as high as 54.1%could be achieved with the solvent in one-stage extraction at 30℃in 30 min with a DES/oil mass ratio of 1:1.Deep desulfurization was realized after five-stage extraction,and sulfur content in model oil was reduced to less than 10μg/g.The used[Bmim]Br-2PG DES was regenerated and showed an extraction efficiency of 50.5%within four recycles.

Photocatalytic oxidative of Keggin-type polyoxometalate ionic liquid for enhanced extractive desulfurization in binary deep eutectic solvents

A series of novel binary deep eutectic solvents(DESs)composed of choline chloride(ChCl)and formic acid(HCOOH)with different molar ratios have been successfully synthesized and applied in extractive desulfurization(EDS).Keggin-type polyoxometallate ionic liquid[TTPh]_(3)PW_(12)O_(40) was prepared and used as catalyst to enhance the EDS capacity by means of photocatalytic oxidative process.Both of the DESs and[TTPh]_(3)PW_(12)O_(40) ionic liquid catalyst were characterized in detail by Fourier transform infrared spectroscopy spectra(FT-IR),elemental analysis,and X-ray photoelectron spectroscopy(XPS).It was found that the molar ratios of Ch Cl:HCOOH had a major impact on desulfurization performance,and the optimal desulfurization capacity 96.5%was obtained by ChCl/5 HCOOH.Besides dibenzothiophene(DBT),the desulfurization efficiencies of 4-methylbenzothiophene(4-MDBT)and 4,6-dimethyldibenzothiophene(4,6-DMDBT),two kinds of DBT derivatives,were also investigated under the same experimental conditions.Moreover,the free radical scavenging experiments manifested that superoxide radical(·O_(2)^(-)) and hole(h^(+)) played important roles in the desulfurization system.After further analysis of the oxidation products by gas chromatography-mass spectrometry(GC–MS),the possible reaction mechanism was proposed.Thus,photocatalytic oxidative has been proved to be one of the efficient approaches for enhancing the extractive desulfurization performance in DES.

Deep extractive desulfurization of diesel fuels by FeCl_3/ionic liquids

The extractive desulfurization of dibenzothiophene（DBT）,benzothiophene（BT）,and 4,6-dimethyldi-benzothiophene （4,6-DMDBT） in model oil was carried out using anhydrous FeCl_3 and 1-methyl-3-octylimidazolium chloride system（[Omim｜Cl·2FeCl_3）.This new system exhibited high extractive efficiency and the sulfur removal of DBT in model oil（V_（IL）/V_（oil）=1/20） could reach 99.4%at room temperature for 30 min,which was obviously superior to single[Omim]Cl as extractant（22.9%）.When the[Omim｜CI·2FeCl_3 was used,the S-removal of 4,6-DMDBT and BT could also be up to 99.3%and 96.2%, respectively.Moreover,the ionic liquid could be recycled five times without a significant decrease in extractive ability.

Extractive desulfurization of fuel oil with metal-based ionic liquids

Several metal-based ionic liquids（ILs） were synthesized and used as extractants for the desulfurization of dibenzothiophene（DBT） in simulated fuel oil.The effects of several anion and metal ions,n（ILs）/n（metal） as mole ratio,V（IL）/V（oil） and extractive times on the removal ratio of DBT were investigated in detail.The results showed that[BMIM]HSO4/FeCl3（BMIM was short for l-butyl-3-methyl imidazole）was superior to the other ILs for the extractive desulfurization.A total of 100%of DBT was removed at room temperature in 5 min with V[BMIM]HSO4/Fecl3/Voil = 1：1.The extractive activity of[BMIM]HSO4/FeCl3 IL did not change almost after five runs.Extractive desulfurization of different sulfur compounds and commercial diesel fuel oil were also examined.The removal ratios of the sulfur compounds as the reaction substrates were all over 90%and the sulfur content of commercial diesel oil decreased to120 ppm from 12,400 ppm.

Extractive desulfurization of model fuels with a nitrogen-containing heterocyclic ionic liquid

A nitrogen-containing ionic liquid was synthesized using an aromatic nitrogen-containing heterocyclic and an amino acid,and applied to the extractive desulfurization process to remove benzothiophene,dibenzothiophene,and 4,6-dimethyldibenzothiphene from a model fuel oil.Chemical characterizations and simulation using Gaussian 09 software confirmed the rationality of an ionic liquid structure.Classification of non-covalent interactions between the ionic liquid and the three sulfur-containing contaminants was studied by reduced density gradient analysis.The viscosity of the ionic liquid was adjusted by addition of polyethylene glycol.Under extraction conditions of the volume of ionic liquid to oil as 1:1 and temperature as room temperature,the desulfurization selectivity of ionic liquid followed the order of 4,6-dimethyldibenzothiphene(15 min)<benzothiophene(15 min)≈dibenzothiophene(10 min).Addition of p-xylene and cyclohexene to the fuel oil had little effect.The extractant remained stable and effective after multiple regeneration cycles.