The Deep Oxidative Desulfurization of Fuels Catalyzed by Surfactant-type Octamolybdate in Acidic Ionic Liquids

Four surfactant-type octamolybdates were synthesized, characterized, and then used as effective catalysts associated with H₂O₂ as oxidant in the acidic ionic liquid, which has been found suitable for deep removal of organic sulfur in fuels. Under the favorable conditions, the sulfur removal could reach almost 100%, which was much better than desulfurization performance by the simple extraction with acidic ionic liquid. Moreover, this acidic ionic liquid can be recycled six times by distillation without obviously decrease in activity. Meanwhile, the mechanism of oxidation desulfurization was also elaborated.     

Deep Oxidative Desulfurization of Dibenzothiophene in Simulated Diesel with Tungstate and H2O2 in Ionic Liquids

Abstract

A green extraction and catalytic oxidative desulfurization (ECODS) system composed of simple tungsten-containing catalyst, 30 wt% H₂O₂, and ionic liquids was discovered suitable for the deep removal of dibenzothiophene (DBT) in simulated diesel. In the case of the system comprising Na₂WO₄ · 2H₂O, 30 wt% H₂O₂ and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄), the removal of DBT could reach 99.7% at 60°C for 3 hr, which was superior to mere solvent extraction with ionic liquid or catalytic oxidation without ionic liquid. This desulfurization system could be recycled five times with a small decrease in activity.     

Optimization of Oxidative Desulfurization of Dibenzothiophene Using a Coordinated Ionic Liquid as Catalytic Solvent

Abstract

Oxidative desulfurization (ODS) of dibenzothiophene (DBT) in n-octane with hydrogen peroxide/acetic acid using a quaternary ammonium coordinated ionic liquid (IL) (C₄H₉)₄NBr · 2C₆H₁₁NO as catalytic solvent has been studied. The ODS mechanism by coordinated ionic liquid [(C₄H₉)₄NBr · 2C₆H₁₁NO] was also carried out. The sulfur-containing compounds in model oil were extracted into ionic liquid phase and oxidized to their corresponding sulfones by H₂O₂. The effect factors for desulfurization of model oil were investigated in detail by means of monofactorial and orthogonal experiments (L₁₆(4)⁴). The results showed that the desulfurization efficiency of model oil could reach 98.6% under the optimal conditions of oxidation time, oxidation temperature, molar ratio of H₂O₂/sulfur (O/S), and volume ratio of model oil to coordinated ionic liquid were 30 min, 50°C, 16, and 1, respectively. The influences to the desulfurization efficiency of DBT decreased in the following order: volume ratio of model oil to coordinated ionic liquid (C₄H₉)₄NBr · 2C₆H₁₁NO (V_{model oil}/V_IL) > molar ratio of O/S > oxidation temperature > oxidation time, according to extreme analysis of the orthogonal test. The coordinated ionic liquid (C₄H₉)₄NBr · 2C₆H₁₁NO can be recycled 5 times without a significant decrease in desulfurization.     

Synthesis of amphiphilic peroxophosphomolybdates for oxidative desulfurization of fuels in ionic liquids

Three amphiphilic peroxophosphomolybdates [C₄mim]₃PMo₄O₂₄, [C₈mim]₃PMo₄O₂₄ and [C₁₆mim]₃PMo₄O₂₄ were synthesized and characterized. These catalysts were used for extraction and catalytic oxidative desulfurization of fuel with H₂O₂ as an oxidant and ionic liquid [C₄mim]BF₄ as an extractant. It was found that [C₁₆mim]₃PMo₄O₂₄ showed the highest catalytic activity and the sulfur content could decrease to 7.5 ppm. In contrast, the desulfurization system shows very low performance without H₂O₂ or ionic liquid. The detailed reaction conditions were optimized including reaction time, temperature, the dosage of H₂O₂ and catalyst, and different sulfur compounds. After the reaction, the catalysts and the ionic liquid can be cycled 8 times with a little decrease in desulfurization efficiency.     

Desulfurization using an oxidation/catalysis/adsorption scheme over H3PW12O40/SiO2−Al2O3 1

A desulfurization experiment was performed with tert-butyl hydroperoxide (t-BuOOH) as the oxidant in the presence of H₃PW₁₂O₄₀/SiO₂₋Al₂O₃ as the catalyst prepared by the sol-gel method, by using dibenzothiphene (DBT) in petroleum ether as the model compound. This work presents the results for the desulfurization by an oxidation/catalysis/adsorption scheme. The effects of catalyst amounts, t-BuOOH amounts, reaction temperature, and reaction time on the desulfurization efficiency and regeneration performance of the catalyst were studied. It was found that the H₃PW₁₂O₄₀/SiO₂-Al₂O₃ catalyst presented a higher maximum desulfurization conversion than SiO₂-Al₂O₃ solids also prepared by the sol-gel method. In addition, the H₃PW₁₂O₄₀/SiO₂-Al₂O₃ catalyst showed a higher desulfurization conversion after regeneration with N,N-dimethylamide. It was also found that the oxidation agent t-BuOOH resulted in a higher desulfurization conversion than hydrogen peroxide (H₂O₂). The text was submitted by the authors in English.     

Oxidative Desulfurization of Dibenzothiophene Catalyzed by VO(acac)2 in Ionic Liquids at Room Temperature

A simple extraction and catalytic oxidative desulfurization (ECODS) system composed of VO(acac)₂, 30% H₂O₂, and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄) has been found to be suitable for the deep removal of dibenzothiophene (DBT) in model oil at room temperature. The optimal conditions were as follows: [n(H₂O₂)/n(DBT)/n(catalyst) = 100:20:1], model oil = 5 mL, ionic liquid [IL] = 1 mL, T = 30°C, t = 2 hr. With the ECODS system, the sulfur removal of DBT could reach 99.6%, which was superior to that of the simple extraction with IL (15.6%) or oxidation without catalyst (17.1%). The IL could be recycled five times without a significant decrease in activity.     

[bmim]OH和[A336][FeCl_4]混合离子液体氧化吸收硫化氢

为了降低非水相催化氧化硫化氢体系的运行成本,将碱性的氢氧化1-丁基-3-甲基咪唑([bmim]OH)离子液体与价格较低的酸性三辛基甲基铵四氯铁酸盐([A336][FeCl_4])离子液体分别按照0.2∶1、0.5∶1、0.8∶1、1∶1和2∶1的比例混合,用所得到的混合离子液体进行硫化氢氧化吸收实验,系统研究了混合离子液体的水溶性、密度、红外光谱、黏度和酸性强度等性能,并对其硫容和反应产物进行了分析。研究结果表明:(1)[A336]FeCl_4季铵盐离子液体的酸性强度和价格均低于[bmim]Fe Cl4离子液体,可以降低离子液体非水相催化氧化硫化氢体系的成本;(2)混合离子液体不仅同时具有[bmim]OH和[A336][FeCl_4]的骨架结构,且其p H值、黏度和硫容均随[bmim]OH量的增加而增加;(3)混合离子液体明显弱于[A336][FeCl_4]离子液体的酸性强度,有利于硫化氢的吸收,其黏度随温度上升而剧烈下降的性质有利于中、高温脱硫。结论认为,当[bmim]OH/[A336][FeCl_4]的物质的量之比在0.5∶1~1∶1时,可以构建成本较低、酸性适中、黏度较低、硫容较高的中、高温脱硫体系。     

An Improved Desulfurization Process Based on H2O2/Formic Acid Oxidation and Liquid-Liquid Extraction 2. FCC Diesel Oil Feedstocks

Abstract

Semi-empirical molecular orbital theory and parametric model 3 methods were used to calculate the quantum chemistry properties of dibenzothiophene (DBT) and its corresponding sulfone compounds to investigate the essential theory of a formic acid/H₂O₂ oxidation desulfurization system. To study oxidation kinetics of the oxidation desulfurization reaction, DBT was also employed as a model compound to obtain the oxidation kinetic parameters. Desulfurization of fluid catalytic cracking (FCC) diesel was also performed in this process, and the sulfur content was reduced from 7,200 μg·g^?1 to 598 μg·g^?1 after being extracted by polyethylene glycol 200.     

The Research of Ultra-deep Desulfurization in Diesel via Ultrasonic Irradiation Under the Catalytic System of H2O2-CH3COOH-FeSO4

Abstract

In recent years, many countries have drawn up strict laws regarding the sulfur-containing compounds of fossil fuels, especially the gasoline and diese. Ultra-deep desulfurization of fuel is a main component of fossil fuel development. The experiment imposes the photochemistry field on the catalytic oxidation system in order to broaden the newly desulfurization technology. The sulfur-containing compounds, such as dibenzothiophene (DBT) and its derivatives, in diesel fuel are oxidized to corresponding sulfones using H₂O₂-CH₃COOH-FeSO₄ oxidation systems via ultrasonic irradiation. Later, the oxidized sulfur compounds (sulfones) are extracted by a suitable polar solvent. The influences of the catalytic system, reaction time, and ultrasonic source (frequency, intensity) are tested on desulfurization efficiency. Experimental results show that the removal efficiency of the sulfur compound could amount to 97.5%, and the recovery of oil is above 92% under the catalytic system of H₂O₂-CH₃COOH-FeSO₄ by the assistance of ultrasound.     

Deep desulfurization of kerosene by electrochemical oxidation and extraction in Mn2+/Mn3+ electrolyte

In this paper, choosing the mixed solution of MnSO₄ solution and H₂SO₄ as electrolyte, with the progressing of electrolysis reaction, Mn³⁺ was generated as intermediate product, combining with water to produce the oxidation agent MnOOH, which was easy to oxidize the sulfur compounds to generate sulfoxide or sulfone. At the optimal electrochemical oxidation desulfurization conditions, the sulfur content of kerosene decreased from 180 µg/g to 8.87 µg/g and the desulfurization efficiency reached to 95.07%. And the cycle of electrolyte and mechanism of electrochemical oxidation desulfurization has been discussed.     

吡咯烷酮酸性离子液体高效催化纤维素水解制葡萄糖

合成并表征了一系列咪唑类和吡咯烷酮类酸性离子液体,并以这些离子液体作催化剂,采用1-丁基-3-甲基咪唑氯化盐([Bmim]Cl)为溶剂,开展了纤维素催化水解制葡萄糖的研究。先以纤维二糖为模型化合物,考察了纤维二糖-葡萄糖体系的稳定性,后续又分别考察了加水量、加水时间、催化剂种类及用量、反应温度和时间等因素对纤维素水解制葡萄糖反应的影响。结果表明,与咪唑类酸性离子液体相比较,吡咯烷酮类酸性离子液体是更优良的促进纤维素水解的催化剂。采用1-甲基-2-吡咯烷酮甲基磺酸盐(［Hnmp］CH₃SO₃)酸性离子液体为催化剂时,在110℃下,当催化剂、纤维素中包含的葡萄糖单元、水三者的摩尔比为1∶3∶210,加水方式为40 min内每隔10 min加1次,分5次加完时,反应2 h,葡萄糖的收率为68%。     

Oxidation Desulfurization of Thiophene Using Phase Transfer Catalyst/H2O2 Systems

Abstract

In our study, an effective phosphomolybdic acid/hexadecyltrimethyl-ammonium bromide catalyst for oxidative desulfurization of thiophene in a model compound was formed. The oxidation activities of thiophene for a series of heteropoly acids were estimated. The results show that the oxidation activity of thiophene increased with increasing oxidation time, oxidation temperature, and the volume of 30% H₂ O₂ oxidant. The optimal values are 150 min, 40°C, and 3 mL, and sulfur removal attained 96.3% when phosphotungstic acid/hexadecyltrimethylammonium bromide was used as a catalyst.     

Prediction of density and viscosity of ternary systems [C_2q]Br＋[C_4q]Br＋H_2O, [C_2q]Br＋[C_6q]Br ＋H_2O, and [C_4q]Br＋[C_6q]Br＋H_2O at different temperatures using their binary subsystems data

The simple equations for prediction of the density and viscosity of mixed electrolyte solutions were extended to the related properties of mixed ionic liquid solutions. The density and viscosity were measured for ternary solutions [C2q]Br(N-ethylquinolinium bromide)+[C4q]Br (N-butylquinolinium bromide)+H2O, [C2q]Br+[C6q]Br(N-hexylquinolinium bromide)+H2O, and [C4q]Br+[C6q]Br+H2O and their binary subsystems [C2q]Br+H2O, [C4q]Br+H2O, and [C6q]Br+H2O at 15, 20 and 25 °C, respectively. The results were used to test the predictability of the extended equations. The comparison results show that these simple equations can be used to predict the density and viscosity of the mixed ionic liquid solutions from the properties of their binary subsystems of equal ionic strength.     

Desulfurization of model FCC gasoline by extraction with ionic liquid and conventional extraction solvents

To compare the desulfurization performance of conventional extraction solvents and novel ionic liquid, desulfurization experiments by extraction were conducted on sulfolane, acetonitrile, N-formyl morpholine, and [BPy]BF₄ using model Fluid Catalytic Cracking gasoline (thiophene and n-octane) as feedstock. Results showed that the desulfurization rate of ionic liquid was worse than conventional extraction solvents, but its yield of sweet gasoline was higher, which could reach to 90.36%. Among the four solvents, N-formyl morpholine had the best desulfurization performance, while sulfolane was the most stable extraction agent.     

Effect of various sono-oxidation parameters on the desulfurization of diesel oil

The influences of ultrasonic intensity, H₂O₂ concentration, ratio of H₂O₂ to oil and the addition of Fenton reagent on the oxidative desulfurization of diesel oil under ultrasonic irradiation were investigated. It was observed that the oxidative desulfurization of diesel oil fitted pseudo-first-order kinetics under our experimental conditions. Increasing the ultrasonic intensity increased the oxidative desulfurization efficiency of diesel oil. The addition of H₂O₂ enhanced the ultrasonic oxidative desulfurization efficiency of diesel oil. The sono-oxidation treatment in combination with Fenton reagent showed a synergistic effect for diesel oil desulfurization. The catalytic oxidative desulfurization process under ultrasonic irradiation process on diesel oils is an efficient and promising method.     

Amorphous TiO2-supported Keggin-type ionic liquid catalyst catalytic oxidation of dibenzothiophene in diesel

Supported ionic liquid(IL) catalysts [C_nmim]_3PMo_(12)O_(40)/Am TiO_2(amorphous TiO_2) were synthesized through a one-step method for extraction coupled catalytic oxidative desulfurization(ECODS) system. Characterizations such as FTIR, DRS,wide-angle XRD, N_2 adsorption–desorption and XPS were applied to analyze the morphology and Keggin structure of the catalysts. In ECODS with hydrogen peroxide as the oxidant, it was found that ILs with longer alkyl chains in the cationic moiety had a better effect on the removal of dibenzothiophene. The desulfurization could reach 100% under optimal conditions, and GC–MS analysis was employed to detect the oxidized product after the reaction. Factors affecting the desulfurization efficiencies were discussed, and a possible mechanism was proposed. In addition, cyclic experiments were also conducted to investigate the recyclability of the supported catalyst. The catalytic activity of [C_(16)mim]_3 PMo_(12)O_(40)/Am TiO_2 only dropped from 100% to 92.9% after ten cycles, demonstrating the good recycling performance of the catalyst and its potential industrial application.     

Desulfurization by Oxidation/Adsorption Scheme over Ti3(PW12O40)4 Catalyst

Abstract

Due to the future specifications for sulfur content in gasoline, a lot of research work has been done to develop alternative methods for desulfurization. This work presents the results for the desulfurization by oxidation/adsorption scheme over Ti₃(PW₁₂ O₄₀)₄ catalyst. The desulfurization experiment was performed with hydrogen peroxide (H₂ O₂) as the oxidant in the presence of Ti₃(PW₁₂ O₄₀)₄/SiO₂-Al₂ O₃ catalyst and adsorbent prepared by the sol-gel method, by using dibenzothiphene (DBT) in petroleum ether as the model compound. The efficiency of Ti₃(PW₁₂ O₄₀)₄/SiO₂-Al₂ O₃ catalyst and adsorbent prepared by the sol-gel method towards DBT adsorption from model compound was studied. The effects of titanium content of the adsorbent and the reaction conditions, such as the reaction temperature, the amounts of adsorbent and hydrogen peroxide (H₂ O₂), and the reaction time, etc., on the desulfurization efficiency and regeneration performance of the catalyst were investigated. It was found that the Ti₃(PW₁₂ O₄₀)₄/SiO₂?Al₂ O₃ catalyst presented higher maximum desulfurization conversion than SiO₂-Al₂ O₃ solids. In addition, it showed higher desulfurization conversion after regeneration with N,N-dimethylamide. Optimal reaction conditions were determined as: a reaction temperature of 70°C, a Ti (titanium)/H(hydrogen) molar ratio of 3, an adsorbent amount of 5 wt%, a H₂ O₂/S molar ratio of 3, and a reaction time of 2 hr. As a result, the total sulfur content in the petroleum ether solution of DBT could be decreased after oxidation/adsorption scheme from an initial value of 200 μg/g to a value of 2 μg/g, and the desulfurization conversion reached 99%, which is a remarkable result. Further, the said adsorbent also had quite good regenerability.     

塔二联轻烃站脱硫系统参数调整分析

针对塔二联轻烃站脱硫装置天然气中H2S含量变化较大,脱硫不达标的实际情况,对脱硫装置的运行参数进行敏感性分析。分析结果表明,吸收塔操作压力、操作温度及MDEA循环量对净化气中H2S含量影响不大,而再生塔操作参数对脱硫效果的影响非常显著。因此,只对MDEA再生塔操作参数进行调整。结果表明,在塔二联天然气中H2S质量分数增加58%的条件下,对MDEA再生塔操作压力和温度进行微调,可有效降低净化气中H2S含量并使其达标。     

Oxidative Desulfurization of Straight-Run Diesel Fraction

Oxidative desulfurization of straight-run nonhydrotreated diesel fraction with hydrogen peroxide in the presence of Na₂MoO₄ or Na₂WO₄, dibenzyl peroxide, and potassium permanganate; by air bubbling; and in the presence of ionic liquids has been studied. The oxidation products have been recovered from the oxidized diesel fraction using alumina, silica gel, or activated charcoal or via extraction with acetonitrile, N,N-dimethylformamide, or acetone. The best results of the diesel desulfurization have been achieved in the case of dibenzyl peroxide as an oxidizing agent in the presence of Na₂MoO₄.     

Desulfurization From Model of Gasoline by Extraction With Synthesized [BF4]−- and [PF6]−-based Ionic Liquids

Abstract

The authors report that 1-octyl-3-methylimidazolium tetrafluoroborate, [OMIM][BF₄], and 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF₆], ionic liquids were synthesized and tested for their capability to desulfurization from model of gasoline. The results show that the aromatic sulfur compounds with higher π-electron density were favorably adsorbed. The results also show that [BF₄]^?-based ionic liquid displays higher extraction efficiencies than [PF₆]^?-based ionic liquid. Thus, it was shown that the extractive ability of the imidazolium ionic liquids was dominated by the structure of cation and anion. It is also found that the sizes of ionic liquids are important factors affecting the absorption capacity for aromatic sulfur compounds.