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1.
Gangqiang Yu Xiaohui Sui Zhigang Lei Chengna Dai Biaohua Chen 《American Institute of Chemical Engineers》2019,65(2):479-482
Ionic liquids (ILs) are employed for air-drying for the first time. The experimental gas–liquid equilibrium (EQ) of N2/O2 + [EMIM][BF4] and N2/O2 + [EMIM][BF4] + H2O systems under a broad temperature range are measured. The new modified UNIFAC-Lei model is successfully extended to predict the N2/O2-IL-H2O system based on extensive phase EQ data. The air-drying experiment using [EMIM][BF4] as an absorbent is conducted, confirming that this new technology is effective and efficient. © 2018 American Institute of Chemical Engineers AIChE J, 65: 479–482, 2019 相似文献
2.
CO2 permeation through imidazolium-based ionic liquids (ILs, [BMIM][Ac], [EMIM][Ac], [OMIM][Ac], [BMIM][BF4], and [BMIM][PF6]) confined in 1.0, 2.0, and 3.5?nm γ-alumina pores was investigated using molecular dynamics simulation. It was found that the nanopore confinement effect influenced the structure of confined ILs greatly, resulting in a layered structure and anisotropic orientation of ILs. In the center of 2.0-nm pore, the long alkyl chain of [BMIM]+ tended to be parallel to the wall, providing a straight diffusion path benefiting the CO2 permeation. The CO2 diffusion coefficients in confined [EMIM][Ac], [BMIM][Ac], and [OMIM][Ac] were 2.3–4.1, 2.4–6.4, and 14.4–21.7?×?10?10?m2?s?1, respectively. This order was opposite to that in the bulk ILs, because the longer alkyl chain led to a more ordered structure, facilitating CO2 diffusion. In addition, the CO2 solubilities were 445–722?mol?m?3?MPa?1 for the five ILs confined in 1.0?nm pore, which were larger than those in 2.0 and 3.5?nm pores (196–335?mol·m?3?MPa?1), due to the larger free volume. Both parallel orientation of alkyl chain and large free volume could increase the CO2 permeability in confined ILs. 相似文献
3.
Mark T.G. Jongmans Eline Hermens Mark Raijmakers Jenny I.W. Maassen Boelo Schuur André B. de Haan 《Chemical Engineering Research and Design》2012
In the current styrene production process the distillation of the close-boiling ethylbenzene/styrene mixture to obtain an ethylbenzene impurity level of 100 ppm in styrene accounts for 75–80% of the energy requirements. The future target is to reach a level of 1–10 ppm, which will increase the energy requirements for the distillation even further. Extractive distillation is a well-known technology to separate close-boiling mixtures up to high purities. The objective of this study was to investigate whether extractive distillation using ionic liquids (ILs) is a promising alternative to obtain high purity styrene. Three ILs were studied: [3-mebupy][B(CN)4], [4-mebupy][BF4], and [EMIM][SCN]. Extractive distillation with sulfolane and the current conventional distillation process were used as benchmark processes. The IL [4-mebupy][BF4] is expected to outperform the other two ILs with up to 11.5% lower energy requirements. The operational expenditures of the [4-mebupy][BF4] process are found to be 43.2% lower than the current distillation process and 5% lower than extractive distillation with sulfolane extractive distillations. However, the capital expenditures for the sulfolane process will be about 23% lower than those for the [4-mebupy][BF4] process. Finally, the conclusion can be drawn from the total annual costs that all studied extractive distillation processes outperform the current distillation process to obtain high purity styrene, but that the ILs evaluated will not perform better than sulfolane. 相似文献
4.
The effect of two ionic liquids (ILs), namely, 1‐allyl‐3‐methyl imidazolium chloride ([AMIM]Cl) and 1‐ethyl‐3‐methyl imidazolium tetrafluoroborate ([EMIM]BF4), on the surface and volume resistivities, mechanical properties, transparency, and water contact angle of methyl vinyl silicone rubber (MVQ) were investigated. The chemical structures of the two ILs before and after heat treatment were characterized by Fourier transform infrared spectroscopy. The morphology and fluorine and chlorine elemental dispersion were characterized by field emission scanning electron microscopy and energy‐dispersive X‐ray spectroscopy mapping, respectively. The antistatic mechanism was revealed. The results show that the MVQ–[EMIM]BF4 composites had lower surface and volume resistivities than the MVQ–[AMIM]Cl composites. The mechanical properties of the MVQ–[EMIM]BF4 and MVQ–[AMIM]Cl composites were slightly lower than those of the pristine MVQ. With increasing [EMIM]BF4 content, the surface and volume resistivities and water contact angle of the MVQ–[EMIM]BF4 composites decreased. When the content of [EMIM]BF4 was 2.0 phr, the MVQ–[EMIM]BF4 composites showed better antistatic performance with lower surface and volume resistivities of 9.6 × 109 Ω and 1.2 × 1011 Ω cm, respectively. The antistatic mechanism of the MVQ–IL composites was ascribed to the synergistic effect of ionic migration and moisture absorption. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45180. 相似文献
5.
The low water vapor pressures of mixtures of water with the ionic liquids (ILs), [EMIM][EtSO4] and [BEIM][EtSO4], indicate that a process of gas dehydration by absorption in ILs might be an alternative to the classical absorption process with triethylene glycol (TEG). The activity coefficient for an infinite dilution of water in the IL (xIL → 1), which should be low for efficient dehydration, is only about 0.2 for [EMIM][EtSO4] compared to 0.6 for triethylene glycol. In contrast to TEG, losses by evaporation are excluded with ILs as solvents, because they have a negligible vapor pressure. The number of separation stages needed for the absorption in the IL and for the subsequent regeneration of the water‐loaded IL is small, about six and eight, respectively. IL regeneration can be achieved by distillation of water out of the IL (e.g., at 120 °C) and stripping with ambient air, which is not possible in the case of TEG (chemical attack by O2). 相似文献
6.
Daofan Ma Chunying Zhu Taotao Fu Youguang Ma Xigang Yuan 《American Institute of Chemical Engineers》2022,68(6):e17613
The gas–liquid two-phase flow pattern, absorption rate and pressure drop of CO2 absorbed into the aqueous solution of the task-specific ionic liquids (1-aminopropyl-3-methylimidazole tetrafluoroborate [Apmim][BF4] and 1-hydroxyethyl-3-methylimidazole tetrafluoroborate [OHemim][BF4]) and halide-free ionic liquid 1-butyl-3-methylimidazolium methylsulfate [Bmim][CH3SO4] were investigated in a microreactor. The absorption mechanism of the three ionic liquids was analyzed employing the 13C NMR spectroscopy. The [Apmim][BF4] was found to have the best ability of CO2 capture compared with the other two ionic liquids, as chemical absorption occurred between [Apmim][BF4] and CO2, while only physical absorption took place between [OHemim][BF4]/[Bmim][CH3SO4] and CO2. The sequence of CO2 absorption rate in three ionic liquids aqueous solutions is: [Apmim][BF4] > [Bmim][CH3SO4] > [OHemim][BF4]. Furthermore, the effects of gas–liquid flow rate and ionic liquids concentration on CO2 absorption rate and pressure drop were studied, the pressure drop models based on various flow patterns were proposed. 相似文献
7.
The density, viscosity, refractive index, heat capacity, heat of dilution, ionic conductivity, and electrochemical stability
of 1-butyl-3-methylimidazolium bromide ([bmim][Br]), 1-butyl-3-methylimidazolium iodide ([bmim][I]), and 1-butyl-3-methylimidazolium
tetrafluoroborate ([bmim][BF4]) were measured at room temperature or over a temperature range of 293.2 to 323.2 K. The density and refractive index values
of [bmim][I] appeared to be the highest among three ionic liquids (ILs). However, the experimental viscosity values of [bmim][Br]
were higher than those of [bmim][BF4], while the heat capacities and heats of dilution of [bmim][BF4] were higher than those of [bmim][Br]. The cyclic voltammogram of [bmim][br] and [bmim][BF4] indicated electrochemical windows in the stability range from 2.7 V of [bmim][[Br] to 4.7 V of [bmim][BF4]. 相似文献
8.
Jingli Han Chengna Dai Zhigang Lei Biaohua Chen 《American Institute of Chemical Engineers》2018,64(2):606-619
The gas drying technology with ionic liquids (ILs) was systematically studied ranging from the molecular level to industrial scale. The COSMO‐RS model was first used to screen the suitable IL and provide theoretical insights at the molecular level. Toward CO2 gas dehydration, we measured the CO2 solubility in single [EMIM][Tf2N] and in the [EMIM][Tf2N] + H2O mixture, as well as the vapor‐liquid equilibrium (VLE) of [EMIM][Tf2N] + H2O system, to justify the applicability of UNIFAC model. Based on the thermodynamic study, the rigorous equilibrium (EQ) stage mathematical model was established for process simulation. The gas drying experiment with IL was also performed and the water content in gas product can be reduced to 375 ppm. It was confirmed that a less flow rate of absorbent, a higher CO2 recovery ratio and a much lower energy consumption can be achieved with IL than with the conventional triethylene glycol (TEG). © 2017 American Institute of Chemical Engineers AIChE J, 64: 606–619, 2018 相似文献
9.
《Catalysis communications》2008,9(3):337-341
Prins reaction, used to prepare dioxanes, has been limited by complex catalyst separation and reusability. In this article, six water-stable Brønsted acidic task-specific ionic liquids ([HMIM]BF4,[(CH2)4SO3HMIM][HSO4], [(Ac)2BIM]Br, [NMP][HSO4], [BMIM][HSO4] and [BMIM][H2PO4] were synthesized and used as environmentally benign catalysts for Prins reaction under mild reaction conditions for the first time. The process is highly effective and environmentally benign. Furthermore, [BMIM][HSO4] was conveniently separated with the products and easily recycled to catalyze Prins reaction again with excellent yields. 相似文献
10.
UNIFAC model for ionic liquid‐CO (H2) systems: An experimental and modeling study on gas solubility
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Zhigang Lei Chengna Dai Qian Yang Jiqin Zhu Biaohua Chen 《American Institute of Chemical Engineers》2014,60(12):4222-4231
The universal quasichemical functional‐group activity coefficients (UNIFAC) model for ionic liquids (ILs) has become notably popular because of its simplicity and availability via modern process simulation softwares. In this work, new group binary interaction parameters (αmn and αnm) between CO (H2) and IL groups were obtained by correlating the solubility data in pure ILs at high temperatures (above 273.2 K) collected from the literature. the solubility of CO in [BMIM]+[BF4]?, [OMIM]+[BF4]?, [OMIM]+[Tf2N]?, and their mixtures, as well as that of H2 in [EMIM]+[BF4]?, [BMIM]+[BF4]?, [OMIM]+[Tf2N]?, and their mixtures, at temperatures from 243.2 to 333.2 K and pressures up to 6.0 MPa were measured. The UNIFAC model was observed to well predict the solubility in pure and mixed ILs at both high (above 273.2 K) and low (below 273.2 K) temperatures. Moreover, the selectivity of CO (or H2) to CO2 in ILs increases with decreasing temperature, indicating that low temperatures favor for gas separation. © 2014 American Institute of Chemical Engineers AIChE J 60: 4222–4231, 2014 相似文献
11.
This work investigates the ability of 1‐ethyl‐3‐methylimidazolium methanesulphate ([EMIM][MeSO3]) as a green and tuneable solvent for denitrification and desulphurisation studies. Experimental density, surface tension and refractive index data have been measured for the following systems: [EMIM][MeSO3] (1) + pyridine (2), [EMIM][MeSO3] (1) + pyrrole (2), [EMIM][MeSO3] (1) + quinoline (2), [EMIM][MeSO3] (1) + indoline (2), [EMIM][MeSO3] (1) + thiophene (2) and [EMIM][MeSO3] (1) + water (2) over the entire mole fraction of [EMIM][MeSO3] at T = 298.15–323.15 K and P = 1 bar. Further from experimental density, surface tension and refractive index, coefficient of thermal expansivity, excess molar volume, deviation of surface tension and refractive index deviation were also calculated. It was found that the heteroaromatic nitrogen/sulphur compounds are completely miscible in [EMIM][MeSO3]. The surface tension values were found to increase while the refractive index decreases with increasing mole fraction of [EMIM][MeSO3]. The experimental values for surface tension increased in the order: pyridine > thiophene > pyrrole > indoline > quinoline > water and for refractive index: pyridine > pyrrole > indoline > quinoline > thiophene > water. It was found that the composition of [EMIM][MeSO3] has a greater influence than temperature in deciding the surface, optical and thermodynamic properties for similar molecular interaction such as IL–thiophene and IL–pyrrole than dissimilar molecules such as IL–water. Further quantum chemical‐based COSMO‐RS tool was used to estimate the activity coefficient at different composition. © 2012 Canadian Society for Chemical Engineering 相似文献
12.
在规整填料塔中采用离子液体吸收二氧化碳气体,利用计算流体力学(CFD)软件建立可靠的数学模型,系统考察了离子液体结构及规整填料几何参数对吸收过程的传质特性和流体力学性能的影响规律。结果表明,床层压降随气体流速增大而增大,液相传质系数随液体流速的增大而增大。相同阴离子时,随着阳离子碳链长度的增长,吸收过程压降增大,同时液相传质系数减小。相同阳离子时,不同阴离子的离子液体压降大的同时传质系数也大。但离子液体的结构对压降影响不明显。离子液体筛选主要考虑传质系数和溶解度因素,但二者与离子液体结构表现出相反的规律。两种折线结构的规整填料传质性能优于传统的X型和Y型结构。 相似文献
13.
CO2 sorption capacities of the neat and silica‐supported 1‐butyl‐3‐methylimidazolium‐based ionic liquids (ILs) were measured under atmospheric pressure. The silica‐supported ILs were synthesized by the impregnation‐vaporization method and charactrized by N2 adsorption/desorption and thermogravimeteric analysis (TGA). Evaluation of the effects of influential factors on sorption capacity demonstrated that by increase of the temperature, flow rate, and the weight percentage of ILs in sorbents, the sorption capacity decreases. Among the sorbents, [Bmim][TfO] and SiO2‐[Bmim][BF4](50) had the highest capacity. By increasing the IL portion in SiO2‐[Bmim][BF4], the selectivity for CO2 to CH4 could be improved. The CO2‐rich sorbents could be easily recycled. 相似文献
14.
Guoxuan Li Qinghe Gao Qinghua Liu Chengmin Gui Zhigang Lei 《American Institute of Chemical Engineers》2023,69(2):e17914
Ionic liquids (ILs) as promising green solvents were first proposed to extract polycyclic aromatic hydrocarbons (PAHs) from fluid catalytic cracking (FCC) diesel. The COSMO-RS model was used for preliminary screening of IL extractants. The liquid–liquid equilibrium (LLE) experiments were performed to show that the IL [BMIM][BF4] has a high selectivity for the model oil system. Further, the LLE experimental results show that the solubility of 1-methylnaphthalene in [BMIM][BF4] is relatively low, while the IL exhibits a high selectivity of n-hexadecane to 1-methylnaphthalene. This means that the use of [BMIM][BF4] can obtain the high-purity products when considering the almost nonvolatility of IL. Compared to the benchmark process, the multistage countercurrent–reflux extraction process can improve the PAHs purity by about 2% at the expense of 5.06% total annual cost and 6.42% energy consumption, rendering the use of IL to extract PAHs from FCC diesel more feasible in industry. 相似文献
15.
Influence of ionic liquids under controlled water activity and low halide content on lipase activity
Room-temperature ionic liquids (ILs) can be used as reaction media for nonaqueous biocatalysis. However, the purity of ILs
should be considered to understand the influence of ILs on enzyme activity. The major impurities in ILs are water and halide.
In the transesterification of benzyl alcohol with vinyl acetate, the optimal water activities for lipases in [Omim][Tf2N] were similar to those in organic solvents. The chloride impurity in [Omim][Tf2N] seriously influenced the activity of lipase. In this work, the effect of ILs on lipase activity was investigated under
controlled initial water activity and low halide content. The activity of lipase was highly dependent upon the anion structure
of ILs. The initial reaction rate of lipases followed the order [Tf2N]−>[PF6]−>[TfO]−>[SbF6]−≈[BF4]−. All tested lipases showed the highest activities in ILs containing [Tf2N] anion. Particularly, [AAIM][Tf2N] was shown as a suitable reaction medium for biocatalysis. Lipozyme IM showed the highest activity in this IL among tested
ILs. Thermal stability of lipase was also investigated. The higher thermal stability of Novozym 435 was obtained in hydrophobic
and water-immiscible ILs such as [Bmim][Tf2N], [Edmim][Tf2N], and [Bmim][PF6]. 相似文献
16.
N-ethyl-imidazolium-based alkylphosphate ionic liquid (IL), viz. N-ethyl-N-methyl-imidazolium dimethylphosphate ([EMIM][DMP]), N-ethyl-N-ethyl-imidazolium diethylphosphate ([EEIM][DEP]) and N-butyl-N-ethyl-imidazolium dibutylphosphate ([BEIM][DBP]) were demonstrated to be effective for the removal of aromatic sulfur compounds (S-compound) 3-methylthiophene (3-MT), benzothiophene (BT) and dibenzothiophene (DBT) from fuel oils in terms of sulfur partition coefficients (KN) at 298.15 K. It was shown that the extractive ability of the alkylphosphate ILs was dominated by the structure of the cation and followed the order [BEIM][DBP] > [EEIM][DEP] > [EMIM][DMP] for each S-compound studied with their KN-value being 1.72, 1.61 and 1.17, respectively for DBT. For a specified IL the sulfur selectivity followed the order DBT > BT > 3-MT with their KN-value being 1.61, 1.39 and 0.78, respectively for [EEIM][DEP]. The alkylphosphate ILs are insoluble in fuel while the fuel solubility in ILs varies from 20.6 mg(fuel)/g(IL) for [EMIM][DMP] to 266.9 mg(fuel)/g(IL) for [BEIM][DBP]. The results suggest that [EEIM][DEP] might be used as a promising solvent for the extractive desulfurization of fuel, considering its higher sulfur extractive ability, lower solubility for fuel and thus negligible influence on the constituent of fuel, and the ease of regeneration for the spent IL via water dilution process. 相似文献
17.
Silica supported dendrimer encapsulated ruthenium nanoparticles were prepared and evaluated as catalysts in the hydrogenation of citral. The dendrimer encapsulated nanoparticles were prepared using the generation 4 (G4), generation 5 (G5) and generation 6 (G6) hydroxyl-terminated poly(amidoamine) (PAMAM-OH) dendrimers as templating agents with different Ru metal:dendrimer ratios. The effects of ionic liquids as catalyst coatings on the catalytic activity were investigated for the ionic liquids [BMIM][NTf2], [OMIM][NTf2], [BMIM][BF4], [BMIM][PF6], [EMIM][OcS] and [EMIM][EtS]. An enhancement in catalytic activity was observed when utilising [BMIM][NTf2] as an ionic liquid coating with selectivity towards citronellal. 相似文献
18.
Qian Wang Xingmei Lu Xueyuan Zhou Minli Zhu Hongyan He Xiangping Zhang 《应用聚合物科学杂志》2013,129(6):3574-3581
Series of 1‐allyl‐3‐methylimidazolium halometallate ionic liquids (ILs) were synthesized and used to degrade poly(ethylene terephthalate) (PET) as catalysts in the solvent of ethylene glycol. One important feature of these new IL catalysts is that most of them, especially [amim][CoCl3] and [amim][ZnCl3], exhibit higher catalytic activity under mild reaction condition, compared to the traditional catalysts [e.g., Zn(Ac)2], the conventional IL catalysts (e.g., [bmim]Cl), Fe‐containing magnetic IL catalysts (e.g., [bmim][FeCl4]), and metallic acetate IL catalysts (e.g., [Deim][Zn(OAc)3]). For example, using [amim][ZnCl3] as catalyst, the conversion of PET and the selectivity of bis(hydroxyethyl) terephthalate (BHET) reach up to 100% and 80.1%, respectively, under atmospheric pressure at 175°C for only 1.25 h. Another important feature is that BHET can be easily separated from the catalyst and has a high purity. Finally, based on the experimental phenomena, in ‐situ infrared spectra, and experimental results, the possible mechanism of degradation with synthesized IL is proposed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
19.
Quantum chemical studies on the simultaneous interaction of thiophene and pyridine with ionic liquid
The simultaneous interaction of thiophene and pyridine with different ionic liquids:1‐butyl‐1‐methylpyrrolidinium tetrafluoroborate([BPYRO][BF4]),1‐butyl‐1‐methylpyrrolidinium hexafluoro‐phosphate ([BPYRO][PF6]), 1‐butyl‐4‐methylpyridinium tetrafluoroborate ([BPY][BF4]), 1‐butyl‐4‐methylpyridinium hexafluorophosphate ([BPY][PF6]) and 1‐benzyl‐3‐methylimidazolium tetrafluoroborate ([BeMIM][BF4]) were investigated using quantum chemical calculations. A three‐tier approach comprising of partial charges, interaction energies and sigma profile generation using conductor‐like screening model for real solvents (COSMO‐RS) was chosen to study the systems. A quantitative attempt based on the CH‐π interaction in ionic liquid; thiophene–pyridine complexes gave the interaction energies of ILs in the order: [BPY][BF4] > [BPYRO][PF6] > [BeMIM][BF4] > [BPY][PF6] > [BPYRO][BF4]. An inverse relation was observed between the activity coefficient at infinite dilution predicted via COSMO‐RS–based model and interaction energies. The dominance of CH‐π interaction was evident from the sigma profiles of ionic liquid together with thiophene and pyridine. © 2010 American Institute of Chemical Engineers AIChE J, 2011 相似文献
20.
《分离科学与技术》2012,47(6):819-826
A new class of green solvents, known as ionic liquids (ILs), has recently been the subject of intensive research on the extractive desulfurization of fuel oils because of the limitation of the traditional hydrodesulfurization method in catalytically removing thiophenic sulfur compounds. In this work, four thiazolium-based ILs, that is, 3-butyl-4-methylthiazolium dicyanamide ([BMTH][DCA]), 3-butyl-4-methylthiazolium thiocyanate ([BMTH][SCN]), 3-butyl-4-methylthiazolium hexafluorophosphate ([BMTH][PF6]), and 3-butyl-4-methylthiazolium tetrafluoroborate ([BMTH][BF4]), are synthesized. The extractive capability of these ILs in removing thiophene (TS) and dibenzothiophene (DBT) from model fuel oils is investigated. [BMTH][DCA] and [BMTH][SCN] present better extractive desulfurization capability than [BMTH][BF4] and [BMTH][PF6], which may be ascribed to the additional π?π interaction between –C≡N (in [BMTH][DCA] and [BMTH][SCN]) and thiophenic ring (in TS and DBT); DBT in diesel fuel is more efficiently extracted than TS in gasoline. [BMTH][DCA] offers the best desulfurization results, where 64% and 45% sulfur removal are obtained for DBT and TS, respectively, at IL:oil mass ratio of 1:1, 25°C, 20 min. [BMTH][DCA] is thus selected to systematically investigate the effects of temperature, IL:oil mass ratio, initial sulfur content, multiple-extraction, and IL regeneration on desulfurization. The mutual solubility of [BMTH][DCA] with fuel oil is also determined. It is observed that the desulfurization capability is not too sensitive to temperature and initial sulfur content, which is desired in industrial application; the sulfur contents in gasoline and diesel fuel are reduced from 558 ppm to 20 ppm (after 5 cycles) and from 547 ppm to 8 ppm (after 4 cycles), respectively. This work may show a new option for deep desulfurization of fuel oils. 相似文献