Attractive Solvent Research Articles

Applications and Prospects of Ionic Liquids in Microbiology and Biochemical Engineering

Ionic liquids (ILs) have been widely recognized as environmentally benign solvents. Their unique properties, including negligible vapor pressure, non-flammability, a wide liquid range and their tunable physicochemical properties by proper selection of cations and anions, make them attractive green solvents in a variety of fields such as organic synthesis/catalysis, extraction/ separation, and electrochemistry, amongst others. In this paper, the recent technological developments and their prospects in the application of ILs in microbiology and biochemical engineering, including enzymatic reactions, protein folding/refolding and biomass dissolution, are discussed.

Thermodynamics of CO2/2-Methylpiperazine/Water

Aqueous 2-methylpiperazine (2MPZ) is an attractive solvent for CO2 capture from coal-fired power plants. Quantitative NMR spectroscopy was used to speciate at 40 °C 8 m 2MPZ loaded with CO2. 13C NMR spectra were acquired from 0 to 0.37 mol CO2/mol alkalinity (or per amino group). 13CO2 was used for solution preparation to amplify signals from carbamate and bicarbonate. The NMR spectra show that the unhindered 2MPZ monocarbamate is the dominant carbamate species and accounts for more than 75% of the total dissolved CO2; bicarbonate and 2MPZ dicarbamate each only account for up to 10% of the total absorbed CO2. Hindered 2MPZ was not detected. This speciation and CO2 solubility were represented by an electrolyte nonrandom two liquid thermodynamic model developed through data regression. At a CO2 loading giving 1.5 kPa CO2 partial pressure at 40 °C the heat of CO2 absorption varies from 50 to 75 kJ/mol at 40–140 °C. At 40 °C the equilibrium CO2 partial pressure was 0.5 kPa at 0.265 mol CO2/mol alkalinity and ...

Equilibrium Study on Reactive Extraction of Lactic Acid with Tri-n – Butyl Phosphate in n - Hexane

Extraction of carboxylic acids from dilute aqueous solution using traditional solvents such as ketones, alcohols, ethers, and ester is inefficient because the distribution ratio is rather low. Reactive extraction which exploits reversible chemical complexation is an effective separation process for extraction of carboxylic acids from aqueous streams such as fermentation broths and wastewaters. In the extraction process, selection of the solvent is an important aspect to be considered. Considering its solubility in water, cost and availability, tri-n-butyl phosphate (TBP) seems to be an attractive solvent for the extraction of lactic acid from aqueous solution. The purpose of this experiment is to study the equilibrium of the reactive extraction of lactic acid in aqueous solution with TBP in n-hexane. The parameters studied in this experiment were initial concentration of lactic acid in the aqueous phase, TBP concentration in n-hexane phase, and the extraction temperature. The experiments at ambient temperature were carried out using a separatory funnel, while the experiments at other than ambient temperature were carried out using erlenmeyer flask and water bath shaker to adjust the temperature. In this experiment, the initial concentration of lactic acid was varied from 0.1 to 0.5 gmol/dm3. The range of initial TBP concentrations in n-hexane was 0.1 to 1.0 gmol/dm3 and the extraction temperature range was 283 to 313 K. The experimental results showed that the higher the initial concentration of lactic acid in aqueous solution, the higher the distribution ratio for a fixed TBP concentration and extraction temperature. For a fixed initial concentration of lactic acid in aqueous solution and extraction temperature, the distribution ratio of lactic acid is increased by increasing TBP concentration. The overall equilibrium constants (Kpq) for the experiments using TBP concentration ranging from 0.1 to 1.0 gmol/dm3 at the extraction temperature of 293 K are calculated to be 0.0668 to 0.5144. Kpq for the experiments at the temperature ranging from 283 to 313 K at the initial concentration of lactic acid of 0.2 gmol/L are found to be 0.0122 to 0.8856. The Kpq as a function of temperature (T) in K can be expressed as ln Kpq = 10,596/T - 38.08 with sum of square of error of 0.14.

Kinetics of Carbon Dioxide Reaction with Aqueous Mixture of Piperazine and 2‐Amino‐2‐ethyl‐1,3‐propanediol

AbstractCurrent researchers from environmental and industrial fields are focusing on advanced means of carbon dioxide (CO2) capture to limit its consequences in process industries. They also intend to enhance the mitigation of environmental impart by CO2 especially its greenhouse effect. In this study, the kinetics of CO2 reaction with an aqueous blend of piperazine (PZ) and 2‐amino‐2‐ethyl‐1,3‐propanediol (AEPD) were investigated. It was found that blending of AEPD with a little percentage of PZ generated the observed rate constant, ko, values that were more than twice the direct summation of the ko values of the aqueous pure amines at the corresponding concentration and temperature. The kinetic study of the system was modeled using a termolecular mechanism. Blending 0.05 kmol/m3 of PZ with 0.5 kmol/m3 of AEPD gives an observed rate constant ko value of 2397.9 s−1 at 298 K. This result is comparable to rate constants of other amine mixtures. Thus, the aqueous blend of AEPD with PZ is an attractive solvent for CO2 capture that has good advantages. The PZ that serves as the promoter in the reaction is needed in small fraction, whereas AEPD, which is a sterically hindered amine, increases CO2 absorption capacity of the system. AEPD can be produced from renewable materials. © 2013 Wiley Periodicals, Inc. Int J Chem Kinet 45: 161–167, 2013

Thermal Degradation of Piperazine Blends with Diamines

Concentrated, aqueous piperazine (PZ) has been developed as an attractive solvent for use in CO2 capture for coal- fired power plants because of its low degradation rate, high CO2 capacity, and high CO2 absorption rate, but its use may be limited by precipitation of solids at low and high CO2 loading. In this work we examine the effects of blending diamines, such as hexamethylenediamine (HMDA), 1,4-diaminobutane (DAB), or bis(aminoethyl)ether (BAE), with PZ on thermal degradation of the amine. The presence of the diamine does not catalyze the thermal degradation of piperazine and appears to degrade independently of piperazine; in particular, HMDA and BAE appear to have thermal degradation rates that are competitive with piperazine.

Carbon Capture with 4 m Piperazine/4 m 2-Methylpiperazine

An equimolar diamine blend of 4 m 2-methylpiperazine (2MPZ) with 4 m piperazine (PZ) is shown to be an attractive solvent for CO2 capture. This blend overcomes the difficulties posed by the narrow solid solubility window of pure 8 m PZ while preserving its benefits. The solid solubility window at 20°C broadens from ▪ to ▪. As the blend viscosity is nearly double that of pure PZ, normalizing the capacity by viscosity shows a practical capacity comparable to MEA at 0.63mol CO2/kg solvent. The CO2 absorption rate of the blend is lower, with ▪ at 40°C, 84% that of PZ. The heats of CO2 absorption of the blend and PZ are equal at ΔHabs=70kJ/mol. While the blend thermal stability is decreased, Tmax = 155 compared to 163°C, oxidative stability is similar. Lastly, their volatilities are nearly equal with amine Henry's constant near 23Pa at 40°C. In short, the equimolar blend of 4 m 2MPZ with 4 m PZ is a competitive solvent for amine scrubbing.

Reaction kinetics of CO2 absorption in to phosphonium based anion-functionalized ionic liquids

The reaction kinetics between CO2 and trihexyl(tetradecyl)phosphonium ([P66614])-based ionic liquids (ILs) with prolinate ([Pro]), 2-cyanopyrrolide ([2-CNpyr]), and 3-(trifluoromethyl)pyrazolide ([3-CF3pyra]) anions are studied at temperatures from 22-60 °C. The absorption of CO2 is carried out in a stirred reactor under pseudo first order conditions. ILs are diluted to concentrations of 0.05, 0.1 and 0.15 M with tetraglyme--a nonreactive, low volatility solvent with much lower viscosity than the ILs. Physical solubility of CO2 in the mixtures is calculated using correlations developed from CO2 solubility measurements in tetraglyme and the N2O-analogy for ILs and dilute IL solutions. The diffusivity of CO2 is estimated from viscosity-dependent correlations chosen after a thorough literature review. The results indicate partial first order reaction kinetics with respect to IL with values ranging from 19,500 L mol(-1) s(-1) ([P66614][Pro]) to 3200 L mol(-1) s(-1) ([P66614][3-CF3pyra]) at 22 °C. The second order reaction rate constants follow Arrhenius behavior with the highest activation energy of 43 kJ mol(-1) measured for [P66614][Pro]. ILs with aprotic heterocylic anions (AHA), on the other hand, show small activation energies of 18 and 11 kJ mol(-1) for [P66614][3-CF3pyra] and [P66614][2-CNpyr], respectively. The ILs studied in this work exhibit reactivity comparable to or higher than common aqueous amines. High reaction rates and tunable capacity make ILs, and AHA ILs in particular, attractive solvents for CO2 separations.

Towards carbon-free flame spray synthesis of homogeneous oxide nanoparticles from aqueous solutions

Flame-assisted spray pyrolysis (FASP) is a versatile process for synthesis of nanoparticles from a broad choice of precursors and solvents. Water is an attractive solvent particularly for inexpensive inorganic precursors (e.g. metal nitrates) as it can effectively reduce the process cost. Furthermore when water usage is combined with a carbon-free fuel (e.g. H2), nanoparticles can be made without forming CO2. Here such a FASP process is explored for synthesis of Bi2O3 and other oxide nanoparticles from aqueous precursor solutions. The flame temperature was measured by FTIR emission–transmission spectroscopy while powders were characterized by X-ray diffraction and N2 adsorption. At low FASP fuel gas (H2 or C2H2) flow rates or process temperatures, product powders had a bimodal crystal size distribution. Its large and small modes were made by droplet- and gas-to-particle conversion, respectively. Homogeneous Bi2O3 and CeO2 powders were obtained for sufficiently high flow rates of either C2H2 or H2. Prolonged high temperature residence times promoted precursor evaporation from the spray droplets and yielded homogeneous nanostructured powders by gas-to-particle conversion. In contrast, FASP of aqueous solutions of aluminum nitrate yielded rather large particles by droplet-to-particle conversion at all fuel flows investigated.

Solubilities of CO2, H2, N2 and O2 in ionic liquid 1-n-butyl-3-methylimidazolium heptafluorobutyrate

Ionic liquids (ILs) are promising in the capture and separation of CO2. In this work, IL 1-n-butyl-3-methylimidazolium heptafluorobutyrate, [C4mim][CF3CF2CF2COO], has been synthesized and characterized by 1H, 13C and 19F NMR spectra. Solubilities of CO2, H2, N2 and O2 in this IL have been determined at the temperature range from (303.15 to 333.15)K and the pressure up to 8.9MPa. From these data, the Henry’s constant, the standard state solution Gibbs energy, standard state solution enthalpy and standard state solution entropy of these gases in [C4mim][CF3CF2CF2COO] were derived and analyzed from molecular interactions. It was shown that the solubility of CO2 is obviously higher than that in [C4mim][CF3COO] and [C4mim][CF3SO3] reported in literature, which makes this IL an attractive solvent for gas separation processes. Furthermore, these solubility data were well correlated by Pitzer model.

Solubility of Carbon Dioxide in the Ionic Liquid 1-Ethyl-3-methylimidazolium Tris(pentafluoroethyl)trifluorophosphate

Recently, the use of ionic liquids (ILs) for gas separation processes has attracted much attention because of the high solubility of different gaseous species in ILs. This contribution presents new experimental measurements of the carbon dioxide (CO2) solubility in the IL 1-ethyl-3 methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]). This solubility has been determined by measuring the bubble point pressures of the binary mixture of [emim][FAP] + CO2 for CO2 concentrations ranging from (10.03 to 60.00) mol % and within a temperature range of (283.75 to 364.13) K using a synthetic method. The obtained values are compared to the solubilities of CO2 in other 1-ethyl-3-methylimidazolium based ILs, to study the effect of the anion. This comparison shows that the solubility of CO2 in the various ILs decreases in the order: [emim][FAP] > [emim][Tf2N] > [emim][EtSO4] = [emim][PF6] > [emim][BF4]. Therefore, the use of [emim][FAP] results in highest absorptive capacity, which makes this IL an attractive solvent for gas separation processes.

녹색용매 기술동향

Green Chemistry emerged at the end of 20th century, which aims the development of the technologies for the sustainable society at the molecular level. Most products we consume in everyday life are produced through chemical processes, and we often oversee the fact that huge amount of solvents are used and disposed. At the present time most solvents used in laboratories as well as industries are volatile organic compounds(VOC), which gives health and environmental problems. Therefore scientists are seeking new materials which have equivalent properties of VOCs as solvent, and at the same time gives no health and environmental problems. In this brief review, the author describes the present status of research and development activities of green solvent materials throughout research societies worldwide. At present the most attractive green solvent candidates are water, glycerol, supercritical carbon dioxide and ionic liquids. In order to give the pictures of these materials, the author tried to introduce the overall aspects of green solvents in various chemical reaction as well as catalytic roles.

Solubility of carbon dioxide in the low-viscosity ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate

The solubility of carbon dioxide (CO2) in a new low-viscosity and non-fluorinated ionic liquid, 1-hexyl-3-methylimidazolium tetracyanoborate ([hmim][TCB]), has been studied experimentally using a synthetic method. Bubble point pressures (up to 12.34MPa) of the system CO2+[hmim][TCB] are reported for CO2 concentrations ranging from 10.09 to 70.16mol% and within a temperature range of 283.56–364.04K. The experimental values of the density, the viscosity and the surface tension of [hmim][TCB] are also reported. The results obtained are compared to available CO2 solubility data and physicochemical properties of other 1-hexyl-3-methylimidazolium based ionic liquids in order to study the effect of the type of anion. It is found that [hmim][TCB] shows higher CO2 absorptive capacity (higher solubility) as well as faster CO2 mass transfer kinetics (lower viscosity), which makes this ionic liquid an attractive solvent for gas separation processes.

Corrosion/passivation of aluminum current collector in bis(fluorosulfonyl)imide-based ionic liquid for lithium-ion batteries

The corrosion behavior of aluminum foil that is used as the positive current collector for lithium-ion batteries is studied in N-methyl-N-propyl-pyrrolidinium bis(fluorosulfonyl)imide (PMPyr-FSI), which is considered as a highly attractive solvent due to a very low viscosity. This work reports that FSI anion is corrosive for aluminum foil upon anodic polarization (>4.0V vs. Li/Li+). The pitting corrosion is, however, greatly reduced by adding lithium hexafluorophosphate (LiPF6). The anion of the salt is known to be a corrosion inhibitor for aluminum. It likely reacts to generate hydrofluoric acid that then attacks the native aluminum oxide (Al2O3) to produce a strong passivation layer comprising aluminum fluoride (AlF3). Resultantly, the high rate capability, which is the potential merit achievable by using the FSI-containing ionic liquid solvent, can be implemented with a LiCoO2 positive electrode.

Oxidative Degradation of Aqueous 2-Amino-2-methyl-1-propanol Solvent for Postcombustion CO2 Capture

2-Amino-2-methyl-1-propanol (AMP) and the blends of AMP with other amines appear to be commercially attractive solvents for postcombustion CO2 capture by absorption/stripping. Oxidative degradation experiments involving AMP aqueous solutions were performed in a 200 mL glass batch reactor with initial AMP concentrations of 5 mol·kg–1, oxygen partial pressures of 250–350 kPa, and at temperatures of 100–140 °C in order to elucidate the degradation mechanistic pathways. The amine loss was determined by cation ion chromatography (IC), while the degradation compounds were identified and quantified by gas chromatography–mass spectrometry (GC–MS) and anion IC. The possible chemical pathways of AMP oxidative degradation are proposed on the basis of the identified and quantified products and the context of the current amine degradation schemes. The role of O2 in the proposed pathways is much more explicit than the previously proposed MEA oxidation mechanisms.

Recent advances in ionic liquids: green unconventional solvents of this century: part I

The present overview describes ionic liquids as alternate, attractive solvents of today and tomorrow in organic synthesis. Since this subject is too wide and developments have been too fast, only a recent account is presented on indispensable carbon-carbon bond forming named reactions such as Knoevenagel, Michael Aldol, Biginelli Reaction, and so on, which has never been done before exclusively.

MICRONIZATION AND ENCAPSULATION OF FUNCTIONAL PIGMENTS USING SUPERCRITICAL CARBON DIOXIDE

ABSTRACTThis research involves experimental studies of supercritical fluid (SCF)‐based micronization and encapsulation processes exploiting both solvent and antisolvent properties of supercritical CO2 for diverse functional pigments to extend the application of these natural functional pigments. First, the reliability of homemade experimental apparatuses designed and constructed by our research group was tested. Quercetin and β‐carotene were used as model substances in the micronization process via supercritical antisolvent (SAS). Bixin‐rich extract with polyethylene glycol (PEG) 10,000 as encapsulant material was used in the encapsulation process via SAS, while rutin and anthocyanin‐rich extract with PEG 10,000 and ethanol as cosolvents were applied to the formation of polymeric microcapsules via rapid expansion of supercritical solutions (RESS). The processing parameters and the used levels were based on the literature data. SAS process successfully reduced the particle size of quercetin by 4.1 times, while conventional micronization process only reduced the particle size by 1.8 times. Furthermore, it was demonstrated that SAS process can be successfully utilized to coprecipitate microparticles of PEG loaded with bixin‐rich extract. RESS process using ethanol as cosolvent was employed effectively to encapsulate rutin and anthocyanin‐rich extract in the PEG matrix. The data obtained in this study are in good agreement with the previous values reported by several authors using similar operational conditions and equipment. Core material : encapsulant material ratio, core material physical properties, such as solubility in supercritical CO2 and in CO2 + ethanol, and viscosity were key parameters for these processes.PRACTICAL APPLICATIONSThe application of natural food colorants with relevant antioxidant activities, such as carotenoids and flavonoids, as food additives in various food products is seriously hampered by their fast degradation triggered by light, temperature, presence of oxygen, insolubility in aqueous systems and low dispersibility, among others. Their particle size reduction and/or encapsulation have been successfully used to overcome all these drawbacks. SCFs have become an attractive alternative solvent due to their environmentally friendly properties. SCFs may be conveniently used for various applications such as extraction, reactions, micronization and encapsulation, among others. Studies showing the use of SCFs and/or the construction of apparatuses that use these green solvents for solubility enhancement of functional pigments with poor water solubility and/or avoiding degradation of these compounds are extremely important.

Evaporation- and surface-induced morphology of symmetric diblock copolymer thin films: a multibody dissipative particle dynamics study

We apply the multibody dissipative particle dynamics method to exhibit evaporation- and surface-induced morphology of diblock copolymer thin films. We find that when the interactions between A components and B components of the diblock copolymer are symmetric, it is easy to obtain a lamellar morphology perpendicular to the surface. On the contrary, if the interactions between A-blocks and B-blocks are asymmetric, it is easy to obtain a lamellar morphology parallel to the surface. Spherical morphology and disorder morphology are formed when the solvent vapour and surface effect are considered. The order parameter and the film thickness are calculated during the phase-separation process for characterising the film properties. The attractive solvent vapour increases the film thickness and impacts the film morphology of the interface. The attractive surface decreases the film thickness and impacts the film morphology near the surface. Our results are partially helpful for the control of film morphology and film thickness in such kind of materials.

Facile pretreatment of lignocellulosic biomass at high loadings in room temperature ionic liquids

Ionic liquids (ILs) have emerged as attractive solvents for lignocellulosic biomass pretreatment in the production of biofuels and chemical feedstocks. However, the high cost of ILs is a key deterrent to their practical application. Here, we show that acetate based ILs are effective in dramatically reducing the recalcitrance of corn stover toward enzymatic polysaccharide hydrolysis even at loadings of biomass as high as 50% by weight. Under these conditions, the IL serves more as a pretreatment additive rather than a true solvent. Pretreatment of corn stover with 1-ethyl-3-methylimidizolium acetate ([Emim] [OAc]) at 125 ± 5°C for 1 h resulted in a dramatic reduction of cellulose crystallinity (up to 52%) and extraction of lignin (up to 44%). Enzymatic hydrolysis of the IL-treated biomass was performed with a common commercial cellulase/xylanase from Trichoderma reesei and a commercial β-glucosidase, and resulted in fermentable sugar yields of ∼80% for glucose and ∼50% for xylose at corn stover loadings up to 33% (w/w) and 55% and 34% for glucose and xylose, respectively, at 50% (w/w) biomass loading. Similar results were observed for the IL-facilitated pretreatment of switchgrass, poplar, and the highly recalcitrant hardwood, maple. At 4.8% (w/w) corn stover, [Emim][OAc] can be readily reused up to 10 times without removal of extracted components, such as lignin, with no effect on subsequent fermentable sugar yields. A significant reduction in the amount of IL combined with facile recycling has the potential to enable ILs to be used in large-scale biomass pretreatment.

Room temperature ionic liquids as emerging solvents for the pretreatment of lignocellulosic biomass

Room temperature ionic liquids (RTILs) are emerging as attractive and green solvents for lignocellulosic biomass pretreatment. The unique solvating properties of RTILs foster the disruption of the 3D network structure of lignin, cellulose, and hemicellulose, which allows high yields of fermentable sugars to be produced in subsequent enzymatic hydrolysis. In the current review, we summarize the physicochemical properties of RTILs that make them effective solvents for lignocellulose pretreatment including mechanisms of interaction between lignocellulosic biomass subcomponents and RTILs. We also highlight several recent strategies that exploit RTILs and generate high yields of fermentable sugars suitable for downstream biofuel production, and address new opportunities for use of lignocellulosic components, including lignin. Finally, we address some of the challenges that remain before large-scale use of RTILs may be achieved.

Optimization of the labeling yield by determination of the Cu+–acetonitrile complex constant in Cu+-catalyzed nucleophilic exchange reactions in mixed solvent conditions

To apply the Cu+-assisted nucleophilic exchange based radioiodination of aromatic compounds for more lipophilic compounds the reaction is carried out in mixed solvent conditions. Due to its physicochemical properties acetonitrile is an attractive solvent. Although acetonitrile forms complexes with Cu+ decreasing the labeling yield. This article describes a method for the determination of the complex constant at labeling temperature based on a Lineweaver–Burk approach, relating the reaction rate constant and the concentration of precursor in presence of different amounts of acetonitrile. The method also allows to calculate the adjusted amount of copper salt in order to obtain the same high labeling yield as obtained in absence of acetonitrile.