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1.
The formation of gas hydrates is a major issue during the operation of oil and gas pipelines, because gas hydrates cause plugging, thereby disrupting the normal oil and gas flows. A solution is to inject gas hydrate inhibitors such as ionic liquids. Contrary to classical inhibitors, ionic liquids act both as thermodynamic inhibitors and hydrate inhibitors, and as anti-agglomerates. Imidazolium-based ionic liquids have been found efficient for the inhibition of CO2 and CH4 hydrates. For CO2 gas hydrates, N-ethyl-N-methylmorpholinium bromide showed an average depression temperature of 1.72 K at 10 wt% concentration. The induction time of 1-ethyl-3-methyl imidazolium bromide is 36.3 h for CO2 hydrates at 1 wt% concentration. For CH4 hydrates, 1-ethyl-3-methyl-imidazolium chloride showed average depression temperature of 4.80 K at 40 wt%. For mixed gas hydrates of CO2 and CH4, only quaternary ammonium salts have been studied. Tetramethyl ammonium hydroxide shifted the hydrate liquid vapour equilibrium to 1.56 K at 10 wt%, while tetrabutylammonium hydroxide showed an induction time of 0.74 h at 1 wt% concentration. 相似文献
2.
An efficient method for prediction in the capture of SO2 from flue gas by imidazolium ionic liquids was reported, where the concentration of SO2 is 2000 ppm. On the basis of quantitative calculations through a combination of Langmuir simulation, theoretical calculation and quantum chemical method, SO2 absorption and desorption performance from flue gas by twelve kinds of imidazolium ionic liquids with different anions were designed and predicted. Then, among them, five kinds of imidazolium ionic liquids were chosen and prepared to investigate their behavior of SO2 absorption capacity, desorption residue, and available absorption capacity. The results indicated that the experimental values were in good agreement with the predicted values. Thus, an ideal ionic liquid [Emim][Tetz] was obtained through the predictive method for the capture of SO2 of 2000 ppm, which showed high available absorption capacity of 0.24 g SO2 per g ionic liquid and excellent reversibility. 相似文献
3.
This is the first case applying 2-haloethylamine to CO 2 capture. The prospect of global warming and the urgent need to reduce atmospheric concentration of carbon dioxide has prompted
actions at many levels. The conventional capture of carbon dioxide is predominantly based on chemical absorption using ethanolamine.
Recent developments of carbon dioxide capture focus on new materials, such as ionic liquids, zeolites, membranes, carbonaceous
absorbents, and metal–organic frameworks. However, no unique solution exists currently to solve the problem of carbon dioxide
capture. In order to examine the efficiency of 2-chloroethylamine as an absorbent of CO 2, we treated an aqueous solution of 2-chloroethylamine hydrochloride with CO 2 in the presence of an alkali, e.g., NaOH, under ambient conditions. The absorption was complete within 30 min, seemingly
following first-order reaction kinetics. Furthermore, we succeeded in capturing CO 2 from ambient air using 2-chloroethanolamine. The efficiency of 2-chloroethylamine as an absorbent of CO 2 could be attributed to the production of stable 2-oxazolidinone, therefore, this reaction is favored thermodynamically. Compared
with previously reported absorbents, this novel system is capable of capturing CO 2 with an extremely high efficiency of 1 mol per mol absorbent under ambient conditions, even from the atmosphere. This potential
method could be used to capture CO 2 particularly from small, mobile, or low-concentration emission sources. 相似文献
4.
Effects of selected ionic liquids on the efficiency of CPO oxidation of methyl-parathion were studied. In general, the activity of CPO decreases with the increased concentration of ionic liquid. For ionic liquids with the same cation, those with PF 6 ? exhibit strongest inhibition toward CPO, while those with either BF 4 ? or metSO 4 ? show relatively lesser inhibition. It was further demonstrated that even for buffer solutions containing up to 30% concentration of ionic liquids such as EAN, BMIMmetSO 4, and EtPyTFA, CPO still can retain high activity (70–100% compared to that in citrate buffer) for oxidation of methyl-parathion. Photothermal enhancement factors of 3.5 times and corresponding improvements of sensitivity in the determination of organophosphates by the FIA-TLS method are predicted in 30% ionic liquids. 相似文献
5.
Although the flow dynamics of pure liquid drops in other liquids has been well researched, little attention has been paid to the impacts of impurities. Hence, most of research is not directly applicable to the real world. To address this gap, we conducted numerical experiments simulating the rise of pure and contaminated drops. It was selected to study liquid CO 2 drops contaminated with SO 2 under high pressure because such mixtures mimic potential scenarios in which drops may leak from carbon capture and storage (CCS) facilities or pipelines. First, numerical simulation experiments were performed to validate our method by comparing our results with previous research on pure drops. Second, the validated numerical approach was applied to simulations of contaminated drops to investigate how contaminants affect rising drops. The results show that the SO 2 contamination caused changes in deformation, breakup phenomena, rising velocities, surrounding flow fields and drag coefficients. Most importantly, the contamination resulted in the formation of smaller “child drops”; such breakup is not observed in pure CO 2 drops. The formation of child drops in turn affects the streamlines, patterns and areas of wakes behind the contaminated drops. The addition of contaminants also enhances the dissolution rate, which is affected by the contaminant concentration and by the flow dynamics of the rising drop. Our results would improve understanding the rise of impure CO 2 drops, such as drops potentially leaked by future CCS operations. 相似文献
6.
2 H-1,4-Benzoxazines are major heterocyclic compounds with interesting biological and synthetic applications. Therefore, it would be very interesting to develop new efficient methods for their synthesis. Here, we synthesized 2 H-1,4-benzoxazines in one pot using K 2CO 3/H 2O in the ionic liquid of choice, [omim][BF 4]. After reactions, products are extracted from [omim][BF 4] by Et 2O and the ionic liquid is recovered and successfully reused over several recycles. Results show that high yields of 3-aryl-2 H-1,4-benzoxazine derivatives are obtained chemoselectively at room temperature from their corresponding o-aminophenols and phenacyl bromides. To our knowledge, our method represents the most efficient and straightforward route for the synthesis of 3-aryl-2 H-1,4-benzoxazine derivatives in short times and under environmentally benign conditions. 相似文献
7.
CO 2 absorption by liquid-containing amines to form carbamate and bicarbonates is an effective method of CO 2 mitigation from industrial exhausts, but this process is expensive and requires large quantities of amines. Here we modified chitosan, a naturally occurring biopolymer containing NH 2 functions, to use it for CO 2 absorption in aqueous media. Chitosan was dispersed in 40% aqueous NaOH solution then treated with monochloroacetic acid dissolved in isopropanol, to yield O-carboxymethylchitosan. Results show that the CO 2 absorption capacity of O-carboxymethylchitosan is 0.508 g/g, which is higher than the capacity of conventional amines such as 1-aminoamine, 2-methylpropanolamine and methyldiethanol amine, but lower than the capacity of monoethanolamine. A cyclic study showed that O-carboxymethylchitosan is a stable component for CO 2 absorption and regeneration. 相似文献
8.
Due to the slow rate of incorporation of inert-metal ions into free-base porphyrins compared to other transition metals, several
methods have been proposed to accelerate the rate of metalation. However, these methods have disadvantages such as low yields,
difficulties of purification of final products, and environmental effects. To avoid those disadvantages, we reacted Pt(II)
and Pd(II) salts with H 2(TPP), H 2(TMPyP) 4+, and their β-pyrrole derivatives, H 2(Br 8TPP) and H 2(Br 8TMPyP) 4+, in 1-butyl-3-methylimidazolium bromide ([bmim] +Br −) under microwave irradiation. The combination of microwave heating and ionic liquids provides efficient thermal energy transfer
among the porphyrins and metal salts. In addition, ionic liquids stabilize charged species as well as their intermediates,
due to their high dipole moment and high boiling point. This not only shortens the reaction time but also gives high yields
of products at relatively low temperatures, of about 100°C compared to conventional synthesis methods: 150°C for DMF, 190°C
for DMSO. Here, we demonstrate that Pt(II)/Pt(II) metalloporphyrins are synthesized at high rates, e.g. 6–30 min for 100%
metalation, with high yields of 79–93% in [bmim] +Br − by microwave activation. 相似文献
9.
Rapidly increasing concentration of CO 2 in the atmosphere has drawn more and more attention in recent years, and adsorption has been considered as an effective technology for CO 2 capture from the anthropogenic sources. In this paper, the attractive adsorbents including activated carbons and amine-modified materials were mainly reviewed and discussed with particular attention on progress in the adsorbent preparation and CO 2 adsorption capacity. Carbon materials can be prepared from different precursors including fossil fuels, biomass and resins using the carbonization-activation or only activation process, and activated carbons prepared by KOH activation with high CO 2 adsorbed amount were reviewed in the preparation, adsorption capacity as well as the relationship between the pore characteristics and CO 2 adsorption. For the amine-modified materials, the physical impregnation and chemical graft of polyethylenimine (PEI) on the different porous materials were introduced in terms of preparation method and adsorption performance as well as their advantages and disadvantages for CO 2 adsorption. In the last section, the issues and prospect of solid adsorbents for CO 2 adsorption were summarized, and it is expected that this review will be helpful for the fundamental studies and industrial applications of activated carbons and amine-modified adsorbents for CO 2 capture. 相似文献
10.
Urea synthesis, currently the largest use of carbon dioxide in organic synthesis, is conventionally operated at high pressure and high temperature. Here, we report for the first time that urea forms at atmosphere and ambient temperatures by negative corona discharge in gas phase. The conversion of CO 2 and yields of a solid mixture of urea and ammonium carbamate, which was identified by the 13C NMR spectrum, rise with reducing temperatures and increasing molar ratios of NH 3/CO 2 and discharge frequencies. The conversion of carbon dioxide was found to be 82.16?% at 20?°C and 1?atm with a molar flow ratio of n(NH 3)/ n(CO 2) of 2.5. High pressure and high temperature as energy inputs are not necessary. 相似文献
11.
The use of fossil fuels now induces two major issues. First, fossil fuel burning is increasing atmospheric carbon dioxide (CO 2) concentrations and, in turn, global warming. Second, fossil fuel resources are limited and will thus decrease in the long run. As a potential solution, there is a need for ecological manufacturing processes that convert raw plant materials into chemical products. For instance, raw plants can be directly converted into hydroxymethylfurfural, which is a versatile intermediate for the synthesis of valuable biofuels such as dimethylfuran and 5-ethoxymethyl-2-furfural. This technology has two benefits for chemical sustainability. First, the pretreatment step is eliminated, thus contributing to reduction of CO 2 emissions. Second, plants are sustainable resources versus fossil fuels, which are limited. Here, we review current sustainable technologies for the production of biobased products and hydroxymethylfurfural from plants, using in particular ionic liquids. Plant sources include poplar, switchgrass, miscanthus, weed plants, and agave species. 相似文献
12.
Fossil fuels are currently the major energy source and are rapidly consumed to supply the increasing energy demands of mankind. CO 2, a product of fossil fuel combustion, leads to climate change and will have a serious impact on our environment. There is an increasing need to mitigate CO 2 emissions using carbon–neutral energy sources. Therefore, research activities are devoted to CO 2 capture, storage and utilization. For instance, photocatalytic reduction of CO 2 into hydrocarbon fuels is a promising avenue to recycle carbon dioxide. Here we review the present status of the emission and utilization of CO 2. Then we review the photocatalytic conversion of CO 2 by TiO 2, modified TiO 2 and non-titanium metal oxides. Finally, the challenges and prospects for further development of CO 2 photocatalytic reduction are presented. 相似文献
13.
二氧化碳捕集与封存技术(CO_2 capture and storage, CCS)是当前国际上公认的CO_2减排的有效措施,但封存在地下的CO_2仍然因为各种不稳定因素存在泄漏风险,对土壤环境及土壤生态系统产生威胁。选择赤子爱胜蚓为研究对象,通过模拟高浓度CO_2对蚯蚓形态与生理变化的影响,探究CCS泄漏所产生的土壤高浓度CO_2对蚯蚓的毒性效应。研究表明,土壤高浓度CO_2使蚯蚓出现生殖环带肿大、尾部串珠以及断尾等外部形态变化,皮肤和刚毛受到损伤并且表皮发生褶皱等现象;随着CO_2浓度的增加以及暴露时间的延长,蚯蚓的死亡率不断增加,土壤高浓度CO_2对蚯蚓的7 d和14 d半致死浓度分别为26.39%和17.78%;蚯蚓体腔细胞溶酶体中性红保留时间(NRRT)减少。因此,蚯蚓有望作为监测CO_2泄漏的指示生物,NRRT可作为识别CO_2泄漏的敏感指标。 相似文献
14.
等效线图法(isobologram)是评估化学混合物毒性相互作用的经典方法之一,然而该方法仅能评估混合物在某一特殊浓度效应水平(通常为50%的浓度效应水平,即EC50)的联合毒性作用情况。因此,拓展等效线图法并用于不同效应水平下混合物毒性的评估显得尤为必要。以杀菌剂多果定(Dod)和3种离子液体(ILs)包括溴化丁基吡啶([bpy]Br)、溴化己基吡啶([hpy]Br)和溴化辛基吡啶([opy]Br)为混合物组分,采用直线均分射线法设计3组二元混合物体系(Dod-[bpy]Br、Dod-[hpy]Br和Dod-[opy]Br)共15条射线,应用微板毒性分析法系统测定各污染物及其混合物射线对青海弧菌Q67(Vibro qinghaisiense sp. Q67,Q67)的毒性,应用拓展等效线图法分析15条混合物射线在5个不同效应水平(EC20、EC30、EC40、EC50和EC60)的毒性相互作用,并与经典等效线图法和浓度加和模型(CA)评估的结果进行比较。结果表明:以p EC50为毒性指标,3种吡啶ILs对Q67的毒性具有烷基链效应,即毒性大小顺序为Dod-[opy]BrDod-[hpy]BrDod-[bpy]Br; 3组二元混合物体系的15条射线的毒性,随农药Dod浓度比的减少而减弱;拓展等效线图法可以比较直观地表征3组Dod-ILs混合物体系在5个不同效应水平的拮抗作用,且拮抗作用强度随Dod浓度比的增加而变化,即先增强后减弱;拓展等效线图法可以有效地评估二元混合物在多个效应水平的联合毒性相互作用。 相似文献
15.
研究了噻吩在离子液体[HMIM] BF4,[BMIM] BF4和[BMIM] PF6中的电化学聚合,实验证明,噻吩在三种离子液体中均能聚合.将噻吩在离子液体中的电化学聚合应用于模拟汽油脱硫.结果表明:在三种离子液体中都实现了电化学脱除模拟汽油样品中的含硫物质--噻吩.对于不同的离子液体而言,脱硫的最佳电流密度不同,但噻吩的脱除效果均能达到50%-90%. 相似文献
16.
The transformation of the fungicide carbendazim (methyl-2 benzimidazole carbamate) induced by hydroxyl radical generated by
the UV photolysis of H 2O 2 has been studied in dilute aqueous solution. The efficient reaction of hydroxyl radicals with carbendazim led to the rapid
degradation of carbendazim. The study of reaction kinetics yielded a second order rate constant of 2.2±0.3 10 9 M −1 s −1 for HO · radicals with carbendazim. This value is in agreement with a high reactivity of HO · radicals with carbendazim. Most degradation products were identified by high performance liquid chromatography mass spectrometry
(HPLC-MS). In the presence of hydrogenocarbonate and carbonate ions, hydroxyl radicals were quenched and in turn carbonate
radicals CO 3
·− were formed. Carbonate radicals are indeed known to react efficiently with compounds containing electron-rich sites such
as nitrogen or sulfur atoms. The use of a kinetic modelling software gave evidence for the occurrence of such reactions with
carbendazim. The second order rate constant of carbonate radical with carbendazim was equal to 6±2 10 6 M −1 s −1.
Electronic Publication 相似文献
17.
This study was a preliminary step to evaluate the acute toxicity of 1-methyl-3-octylimidazolium chloride ([C 8mim]Cl) on loach ( Misgurnus anguillicaudatus) by determining the effects on hepatic antioxidant enzyme activities and by the comet assay. The results showed that [C 8mim]Cl had acute toxicity at concentrations above 20 mg L ?1, inducing oxidative stress and genotoxicity on fish liver cells. In respect to enzyme activities, [C 8mim]Cl induced changes in the activities of superoxide dismutase, catalase, and glutathione content the livers of fish exposed at 20–80 mg L ?1. [C 8mim]Cl at the same exposure level caused a remarkable increase in malondialdehyde level. The comet assay indicated that [C 8mim]Cl at 20–80 mg L ?1 induced genotoxicity in liver cells. With increased exposure concentration and time, the two comet parameters trailing rate and tail moment were significantly increased, with significant differences ( P < 0.05) observed between control group and each treatment group. The present study shows that ionic liquids can be a threat to the health of aquatic organism when accidentally released to aquatic ecosystems. 相似文献
18.
Gypsum has been applied as a natural fertilizer and soil amendment for centuries in agriculture for providing crop nutrients such as Ca and S, and for improving soil physical properties. Recently, gypsum has been tested for sequestrating CO 2 from the air and for capturing soluble phosphates in the soil, through formation of insoluble calcium phosphates and carbonates. However, the environmental factors controlling these sequestration processes have not been systemically studied. Here, we calculate optimal conditions of sequestration using chemical equilibrium modeling. Our results show that CO 2 carbonation is effective at pH higher than 8.5 at atmospheric concentration. The removal of P is higher than 80 % for pH higher than 6.4, when Ca and P are at stoichiometric ratio. Also, placement of gypsum in subsoil is more effective for CO 2 capture than applying it on soil surface since soil pores often contain higher concentrations of CO 2 due to the soil respiration process. Overall, increases in medium pH, gypsum application rate, or CO 2 partial pressure can increase the effectiveness of the amendment. 相似文献
19.
Carbon dioxide and methane are major compounds involved in global warming. The process of CO 2 and CH 4 molecules absorption by water clusters was investigated by the molecular dynamics method. The frequency spectra of dielectric
permittivity for systems consisting of (H 2O)
n
, (CO 2)
i
(H 2O) 10 and (CH 4)
i
(H 2O) 10 clusters mixed in various proportions were determined. The IR radiation absorption spectra of these systems were calculated
and compared. Also, the radiating power of these systems was established. The capture of greenhouse gases’ molecules by ultra
disperse water media reduces the ability of the media to absorb the Earth’s radiation, i.e., it reduces the greenhouse effect. 相似文献
20.
We report for the first time the direct conversion of raw grape berry biomass to hydroxymethylfurfural (HMF) using ionic liquid
solvents with metal chloride catalysts. Exploiting raw plant biomass as a biorefinery feedstock is innovative for sustainable
chemical industry. The use of the raw biomass to synthesize compounds can indeed lead to less energy consumption and less
CO 2 emissions. Using raw plant biomass skips pretreatment steps that are required to produce biomaterials such as carbohydrates
or cellulosic biomass. Here, grape berry biomass was used as a raw chemical feedstock for the production of hydroxymethylfurfural,
a key platform intermediate for syntheses of future renewable biofuels. We examined 3 ionic liquid solvents, 3 reaction temperatures,
5 chloride catalysts, and 5 concentrations of HCl. We found an increasing HMF yields depending on reaction conditions. 1-octyl-3-methylimidazolium
chloride was most effective for HMF synthesis. Addition of HCl or metal chlorides alone showed little improvement. The highest
HMF yield of about 100 mg HMF per mL of grape biomass extract was obtained using 0.3 M HCl, [OMIM]Cl, and CrCl 2 at 100°C for 3 h. Our study provides a model system of sustainable production of valuable compounds from raw plant biomass. 相似文献
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