Methylammonium Methylsulfate Research Articles

The efficacy of ammonium ionic liquid to inhibit the parasitic process for Al-air battery

The main objective of this study is to determine how effectively the ammonium ionic liquid (tris(2 hydroxyethyl) methyl ammonium methylsulfate [THMA]+[MS]− works in minimizing parasitic reactions during Al-air battery discharge. The findings obtained indicate that the use of [THMA]+[MS]− reduced the rate of hydrogen gas output during the immersion of Al substrate in the 4.0 M KOH solution. The effectiveness of the ammonium ionic liquid under comparable conditions is confirmed using the linear cathodic polarization method. The addition of [THMA]+[MS]− to a pure 4.0 KOH solution improved the anodic efficiency and capacity density of the battery. Aside from being a novel study for [THMA]+[MS]− as electrolyte battery additives, theoretical research were employed to analyze the mechanism and data interpretation. Molecular dynamics (MD) simulations of inhibitor-Al interactions performed with Forcite's Materials Studio module add to the data that ammonium ionic [THMA]+[MS]− may suppress the parasite process. SEM, EDX, and X-ray Photoelectron Spectrometer (XPS) tests for Al electrodes under different circumstances following battery discharge at 20 mA cm−2 support the performance of [THMA]+[MS]−.

Thermodynamic characterization of interactions between environmental contaminants and room temperature ionic liquids using static headspace gas chromatography with vacuum ultraviolet detection

Understanding the thermodynamic interactions between an analyte and the sample phase is of paramount importance when choosing a co-solvent in headspace analysis. A sample phase – gas phase equilibrium partition coefficient (Kp) is used fundamentally to describe the distribution of the analyte between the two phases. Kp determinations by headspace gas chromatography (HS-GC) were acquired by two methods: vapor phase calibration (VPC) and phase ratio variation (PRV). Here, we demonstrated a pressurized – loop headspace system in conjunction with gas chromatography vacuum ultraviolet detection (HS-GC-VUV) to directly calculate the concentration of analytes in the gas phase from room temperature ionic liquids (RTILs) sample phases, using pseudo-absolute quantification (PAQ). PAQ, an attribute of VUV detection, allowed for quick determination of Kp and other thermodynamic properties, such as enthalpy (ΔH) and entropy (ΔS) of the system through the use of van't Hoff plots in the temperature range of 70–110 °C. The Kp determinations by PAQ were comparable to those obtained using the VPC method with percent difference ranging from ≤ 1–33%. Kp determinations were made for analytes (cyclohexane, benzene, octane, toluene, chlorobenzene, ethylbenzene, m-,p-, and o-xylene) at the varying temperatures (70–110 °C) using different RTILs (1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][ESO4]), 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]), and tris(2-hydroxyethyl)methylammonium methylsulfate ([MTEOA][MeOSO3])) and (1-ethyl-3-methylimidazolium bis(trisfluoromethanesulfonyl)imide ([EMIM] [NTF2])). The results from the van't Hoff analysis revealed that [EMIM] cation-based RTILs exhibit strong solute-solvent interactions with analytes that have π- electrons.

Thermal performance analysis of sugarcane bagasse pretreated by ionic liquids

This work investigated the pretreatment effect of four ionic liquids (ILs) on sugarcane bagasse (SCB) through reactivity, kinetic, and thermodynamic analysis. The ILs used in this study were 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), 1-butyl-3-methylimidazolium methylsulfate ([Bmim][MeSO4]), Tris (2-hydroxyethyl) methylammonium methylsulfate ([MTEOA][MeSO4]), and trihexyltetradecylphosphonium chloride ([P66614] [Cl]). Pretreatment was carried out at 150 °C and 30 min, followed by thermal analysis of samples in a thermogravimetric analyzer (TGA). The activity parameters were obtained using TGA data. [P66614] [Cl] was completely absorbed in SCB, which strongly influenced the thermochemical behavior of [P66614] [Cl] treated sample. Results revealed that IL pretreatment greatly reduced ash content and increased the higher heating value (HHV) of SCB. Chemical composition analysis showed delignification of SCB by [Bmim][Cl], [Bmim][MeSO4] and [MTEOA][MeSO4]. However, [P66614] [Cl] increased lignin content indicating thermal stability. The obtained values of activation energy (Ea) for [Bmim][Cl], [Bmim][MeSO4], and [MTEOA][MeSO4] were much lower than that for untreated SCB, suggesting destruction of the lignocellulosic structure. Higher entropy change (ΔS) values after IL treatment implied higher disorder due to the breakage of SCB structure. The study demonstrated that the nature of cations and anions strongly influences the pretreatment potential of ILs for biomass undergoing thermochemical conversion processes.

Electrical shear bonding strength reduction of resin-modified glass-ionomercement containing ionic-liquid: Concept and validation of a smart dental cement debonding-on-demand.

With improvement of bonding strength of recent dental cement, it is difficult nowadays to remove restorations without excessive force or vibration to tooth, occasionally resulting in damage of dentin, enamel, and dental root. Therefore, "smart" dental cement indicating strong bonding and easy debonding-on-demand simultaneously is required. In this research, resin-modified glass-ionomer-cement containing an ionic-liquid, tris(2-hydroxyethyl)methylammonium methylsulfate was produced, and the shear bonding strength before and after direct current application were evaluated. The prototype cement containing 15 to 20 mass% ionic-liquid indicated simultaneously no significant reduction of shear bonding strength from that of the original cement not containing ionic-liquid, and significant reduction of bonding strength to approximately 20% of that of the original cement after direct current application of more than 2 mmC/mm2. The prototype cement in this research demonstrated that the concept of smart dental cement electrically debonding-on-demand is feasible.

Matrix-effect-free determination of BTEX in variable soil compositions using room temperature ionic liquid co-solvents in static headspace gas chromatography mass spectrometry

Concerns about the environmental impact of shale energy exploration (i.e., hydraulic fracturing and other well stimulation techniques) have risen due to its rapid expansion in the United States and other countries. Soils in shale basins engaged in unconventional oil and gas development can become contaminated by volatile organic compounds (VOCs), such as benzene, toluene, ethylbenzene, and xylenes (BTEX) through mishandling of chemical additives, products, and/or waste fluids. In this study, room temperature ionic liquids (RTILs) were evaluated as solvents in an effort to increase sensitivity and to reduce and normalize matrix effects associated with varying soil compositions during analysis. Headspace gas chromatography mass spectrometry (HS-GC-MS) experiments demonstrated that hydrophilic RTILs 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][ESO4], 1-ethyl-3-methylimidazolium diethyl phosphate [EMIM][DEP], and tris(2-hydroxyethyl) methylammonium methylsulfate [MTEOA][MeOSO3] normalized the response for BTEX compounds between 2 different soils, sandy loam and sandy clay loam. Furthermore, the optimization of the HS equilibration time to 30 min resulted in the reduction of matrix effects in certified reference soils of sand, clay, and loam textures. Limits of detection and limits of quantification were in the sub- to mid- pg g−1 level in soil. For determination at 1 g of certified BTEX reference soil, the relative standard deviation was within 10% and percent recoveries were above 80% for toluene, ethylbenzene, and xylenes. This method reduces the need to characterize and matrix-match soil texture for calibration purposes. It also reduces the analysis time and increases precision and accuracy for the quantification of BTEX in variable soil matrices relative to standard methods.

A Preferable Method for the Formation of Vesicles from Lamellar Liquid Crystals Using Chemical Additives.

We present a method for vesicle formation from lamellar liquid crystals (LCs) using a cationic amphiphilic substance, namely 2-hydroxyethyl di(alkanol)oxyethyl methylammonium methylsulfate (DEAE). Vesicle formation from the DEAE lamellar dispersion occurred via a two-step chemical addition. This method required neither additional mechanical energy nor the use of special solvents. The transition was solubilized using an organic substance (e.g., limonene) in the lamellar DEAE LC, after which, a small amount of inorganic salt was added to the solubilized lamellar LC dispersion with gentle stirring. The viscosity of the DEAE dispersion following salt addition decreased sharply from 105 mPa·s to 102 mPa·s, and the DEAE dispersion was converted into a high fluidity liquid. Several organic substances were examined as potential solubilizates to initiate the lamellar-vesicle transition. Inorganic salts were also examined as transition triggers using various types of electrolytes; only neutral salts were effective as trigger additives. Dissociation of inorganic salts yielded anions, which inserted between the DEAE bilayer membranes and induced OH- ion exchange. In addition, a number of cations simultaneously formed ion pairs with the DEAE counter ions (CH3SO4- ions). However, as the amount of solubilized organic substances in the DEAE bilayer membrane decreased over time, the vesicles were transformed into lamellar LCs once again. The DEAE states in each step were measured by monitoring the zeta potential, pH, viscosity, and by examination of scanning electron microscopy and atomic force microscopy images. A possible molecular mechanism for the lamellar-vesicle transition of DEAE was proposed.

Thermodynamic Analysis of the Transition of Liquid Crystals from Lamellar to Vesicular Phase.

Here, we report the results of thermodynamic analyses on the lamellar-vesicular transition for a cationic amphiphilic species, namely 2-hydroxyethyl di(alkanol)oxyethyl methylammonium methylsulfate (DEAE). Previously, we have shown that spontaneous vesicle formation from a Lα-lamellar liquid crystal (LC) phase only occurs on the addition of a quantitative amount of additives to the DEAE LC at certain temperatures and that this change occurs without the input of any extra mechanical energy. These lamellar-vesicular transitions occur in two steps: the first step is the formation of an excited state, caused by the solubilization of organic substances in the bilayer structure. The second step, induced by the addition of a small amount of inorganic salt to the excited LC state, is the transition from lamellar to vesicular phase. From our experimental data, the change in the Gibbs free energy was estimated by assuming an ideal electrical chemical potential. As a result, the thermodynamic parameters at 303 K for the lamellar-vesicular transition from the initial state (lamellar) to the final state (vesicle) were found to be approximately -2.7 kJ/mol for the Gibbs free energy, -14.6 kJ/mol for the enthalpy change, and -11.9 kJ/mol for the entropy change. Each state change was due to structural changes not only in the LC bilayers but also in the hydration structure of the surrounding water. Moreover, the most significant finding is that the free energy change in lamellar-vesicular transition is negative, which may be explained based on the stabilization of solubilized vesicles with respect to the unsolubilized lamellar phases.

Ionic liquid vs tri-block copolymer in a new aqueous biphasic system for extraction of Zn-cholesterol complex

Abstract A new aqueous biphasic system (ABS) was designed by mixing aqueous solutions of tri-block copolymer polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol (PPG-PEG-PPG) with a nontoxic ionic liquid tris (2-hydroxyethyl) methyl-ammonium methyl sulfate. Well defined phase diagram validated with Merchuk equation along with suitable tie-lines was obtained by turbidometric titration method at 298 K. The tie-line lengths and slope of tie lines were calculated and the results were validated using Othmer-Tobias and Bancroft equations. The newly designed ABS has been used to perform the extraction studies of cholesterol, zinc and Zn-cholesterol complex at different pHs of the solution. Zn-cholesterol complex was found to be formed at an acidic pH (1.5). The stability constant value of Zn-cholesterol complex was obtained in ethanolic medium, pristine polymer medium and in the ABS extracted polymer rich phase using Benesi-Hildebrand equation. The aggregation number of PPG-PEG-PPG solution obtained after extraction of cholesterol and Zn-cholesterol complex in ABS was found to be greater in comparison to the pristine copolymer solution. Kinetic spectrophotometric studies were also supporting higher stability of Zn-cholesterol complex in the ABS extracted polymer rich phase. Zn-cholesterol complex formation in acidic micellar medium (pH 1.5) also falls in the pH range of normal human stomach and may offer a suitable method of zinc supplementation by absorption via cell membrane that resembles with the polymeric micellar aggregation.

Improvement of photoluminescence stability of ZnS-AgInS2 nanoparticles through interactions with ionic liquids

Abstract Photoluminescence (PL) stability of ZnS-AgInS 2 (ZAIS) nanoparticles (NPs) prepared via thermal decomposition of (AgIn) x Zn 2(1-x) (S 2 CN(C 2 H 5 ) 2 ) 4 (x = 0.5, 0.8 and 1.0) was improved by ionic liquids (ILs) of 1-ethyl-3-metylimidazolium ethylsulfate (EMI-es) and tris (2-hydroxyethyl) methylammonium methylsulfate (HEMA-mes). Through ligand exchange processes from oleylamine (OLA) to sodium 2-mercaptoethanesulfonic acid (MES), hydrophilic NP’s surfaces changed into hydrophobic ones, resulting in that the ZAIS NPs could be dispersed in the ILs. UV irradiation caused the PL deterioration of ZAIS NPs in solutions, but MES-ZAIS NPs in the ILs exhibited higher PL stability than the OLA-ZAIS NPs in chloroform, the degree being more remarkable for NPs dispersed in HEMA-mes than in EMI-es. The improvement of PL stability could be interpreted as a result of stabilization of MES adsorbed on the NPs through electrostatic interaction between MES and the ILs. Exposing to the air and mixing with the water accelerated the PL deterioration of the NPs.

Solid Liquid Equilibrium of Cellobiose, Sucrose, and Maltose Monohydrate in Ionic Liquids: Experimental and Quantum Chemical Insights

As a substitute of fossil fuels, lignocellulosic biomass is a potential feedstock for the production of energy and value-added chemicals. The present work reports the solubility (solid–liquid equilibria, SLE) of disaccharides, namely, d-(+)-cellobiose, sucrose, and maltose monohydrate in two ionic liquids (ILs) by a combined approach using experiments and predictions with the continuum solvation model. The screened ILs, namely, 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) and tris(2-hydroxyethyl)methylammonium methylsulfate [TMA][MeSO4], were then used as solvents to measure the SLE at a temperature range of 302.15–353.15 K. The IL [EMIM][SCN] gave a higher solubility as compared to [TMA][MeSO4] irrespective of the disaccharide. The solubility trend within the disaccharide was similar in both the ILs, and it followed: maltose monohydrate > sucrose > d-(+)-cellobiose. The interactions were further confirmed from the quantum chemical calculations by investigating the interaction energy and HOMO–LUM...

APPLICATION OF IONIC LIQUIDS IN THE ULTRASOUND-ASSISTED EXTRACTION OF ANTIMICROBIAL COMPOUNDS FROM THE BARK OF CINNAMOMUM CASSIA

This study compares the chemical constituents of extracts from the bark of Cinnamomum cassia obtained with the use of ionic liquids and organic solvents, as well as investigates their antifungal and yeasticidal activity. The type of ionic liquid was found to play a significant role in this process. We found that the ionic liquid tris (2-hydroxyethyl) methylammonium methylsulfate is a most efficient extracting agent, superior to classical solvents such as ethanol, ethyl acetate, hexane, dichloromethane. The obtained extract revealed high antimicrobial activity against yeasts, fungi pathogenic for plants and bees, dermatophytes, filamentous moulds with similar potencies as the standard fungicides.

Solubility of glucose, xylose, fructose and galactose in ionic liquids: Experimental and theoretical studies using a continuum solvation model

A molecular screening of 64 ionic liquids (IL’s) for the solubility of monosaccharides such as d-(+)-Glucose, d-(+)-Xylose, d-(−)-Fructose and d-(+)-Galactose were performed by continuum solvation model (COSMO-RS) over the temperature range of 303.15–373.15K. The IL data set consisted of 31 cations and 23 anions comprising of cations such as imidazolium, ammonium, pyridinium, pyrrolidinium, phosphonium, sulfonium and piperidinium. The imidazolium and ammonium based IL’s gave the highest solubility for cations possessing lesser number of carbon side chains. Based on the screening studies, the following two IL’s were chosen: 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) and Tris(2-hydroxyethyl)methyl ammonium methylsulfate [TMA][MeSO4] to experimentally study the solubility of monosaccharides in the two IL’s. The experimentally obtained solid–liquid equilibria (SLE) values were then compared with COSMO-RS predicted values. The root mean square error (RMSE) values of monosaccharides such as d-(+)-Glucose, d-(+)-Xylose, d-(−)-Fructose and d-(+)-Galactose in [EMIM][SCN] were 3.11%, 3.12%, 2.32% and 1.83% respectively while the corresponding figures in [TMA][MeSO4] is 1.47%, 1.20%, 2.94% and 0.70%. The overall solubility ranking in two IL’s was: d-(−)-Fructose>d-(+)-Xylose>d-(+)-Glucose>d-(+)-Galactose.

Densities of Six Commercial Ionic Liquids: Experiments and Prediction Using a Cohesion Based Cubic Equation of State

Ionic liquids (ILs) are eco-friendly solvents due to their low vapor pressure. Properties such as density should be known as it affects the mass transfer rates. Due to its limitless combinations, it is impractical to measure densities experimentally. For the first time, the cohesion factor in the cubic equations of state (CEOS) is used to predict the densities of six commercial ILs, namely, 1-ethyl-3-methylimidazolium methane sulfonate [EMIM][MeSO3], 1-ethyl-3-methylimidazolium acetate [EMIM][Ac], 1-ethyl-3-methylimidazolium thiocynate [EMIM][SCN], 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO4], Tris(2-hydroxyethyl)-methylammonium methyl sulfate [TEMA][MeSO4], and trihexyl(tetradecyl) phosphonium bis(2,4,4-trimethylpentyl) phosphinate [TDTHP] [Phosph]. CEOS models such as predictive Soave–Redlich–Kwong (PSRK) coupled with cohesion factor gave better results when compared to the correlations such as Reid et al. (RR), Mchaweh et al. (MH), and the linear generalized model (LGM). In this work the PSRK equation of state (EOS) with the derived NSM1 alpha function and PSRK with original SRK alpha function were used for the prediction. PSRK EOS model with NSM1 alpha function and PSRK EOS with original SRK alpha function proved very accurate with average minimum deviation of 0.02 % to 0.44 % and 0.29 % to 0.66 % from experimental values for six ILs, respectively.

CO2 Solubility in Biodegradable Hydroxylammonium-Based Ionic Liquids

The solubility of CO2 in two biodegradable ionic liquids tris(2-hydroxyethyl)methylammonium methylsulfate [THMA][MeSO4] and 2-hydroxyethyl-trimethylammonium lactate [2HETMA][Lac] has been studied experimentally. A synthetic method was used to measure bubble-point pressures up to 8 MPa for a temperature range of 313 K to 363 K. The solubility of CO2 in [2HETMA][Lac] is much higher than in [THMA][MeSO4], but the solubility increment is lower at higher CO2 concentrations. The solubility of CO2 in [THMA][MeSO4] is much lower compared to ionic liquids containing the same anion, but lacking hydroxyl-groups in the cation. The hydroxyl-groups required for the biodegradability of the IL have a detrimental effect on the CO2 solubility. [THMA][MeSO4] and [2HETMA][Lac] are not suitable for CO2 capture and can be considered as an example of a contradictive design where the biodegradability is improved upon introducing hydroxyl-groups, while the CO2 solubility is reduced significantly. The experimental data has been mo...

Liquid–liquid equilibria studies on ammonium and phosphonium based ionic liquid–aromatic–aliphatic component at T = 298.15 K and p = 1 bar: Correlations and a-priori predictions

The commercial ionic liquids (IL), namely tris (2-hydroxyethyl) methylammonium methylsulfate and tributyl methyl phosphonium methyl sulphate were used for the separation of three systems namely benzene–hexane, toluene–heptane and thiophene–cyclohexene at ambient conditions. Liquid–liquid equilibrium (LLE) data were measured for the ternary systems namely, [TEMA][MeSO4] (1)–benzene (2)–hexane (3); [TEMA][MeSO4] (1)–toluene (2)–heptane (3) and [P4441][MeSO4] (1)–thiophene (2)–cyclohexene (3) at T=298.15K and p=1bar. The selectivity and distribution coefficient were further calculated from the tie line data. It was observed that the IL required for the extraction will be less and the cross contamination is nearly zero in both the phases. A comparison was made with the available LLE data of imidazolium and pyridinium cations where the distribution ratios for the present work were the lowest irrespective of cation. Similarly, the experimental selectivity values for benzene–hexane separation were higher than the reported selectivities of different cations. Further the experimental tie line data for ternary systems were correlated with NRTL and UNIQUAC models. For all three ternary systems, the RMSD value ranges from 0.22% to 0.88% and 0.31% to 1.05% for NRTL and UNIQUAC model, respectively. Finally, the quantum chemical based COSMO-RS predictions gave RMSD values of 2.9%, 5.78% and 10.3% for IL–benzene–hexane, IL–thiophene–cyclohexene and IL–toluene–heptane systems, respectively.

Enhancement of enzymatic digestibility of oil palm empty fruit bunch by ionic-liquid pretreatment

In this study, 4-methylmorpholine N-oxide (NMMO) and four ionic liquids were compared to determine the most suitable type for use in pretreatment of oil palm empty fruit bunch (EFB) to enhance enzymatic digestibility and obtain maximal fermentable sugar (glucose). Four types of ionic liquids, namely, 1-ethyl-3-methyl imidazolium acetate ([Emim]OAc), 1-butyl-3-methyl imidazolium chloride ([Bmim]Cl), tributyl methyl ammonium methylsulfate (MTBS), and 1-ethyl-3-methyl imidazolium diethylphosphate ([Emim]DEP), were used. The effects of pretreatment temperature and time on the enzymatic digestibility of EFB were examined. Among NMMO and four ionic liquids, NMMO and [Emim]OAc, showing high enzymatic digestibility, were found to be most effective for EFB pretreatment. The enzymatic digestibility of NMMO-pretreated EFB increased as pretreatment temperature and time increased. After [Emim]OAc pretreatment, the crystallinity index of EFB decreased, due to the conversion of crystalline cellulose to amorphous cellulose, and the enzymatic digestibility thereby was increased to 96.6% at 110 °C for 2 h.

Insights into Tris‐(2‐Hydroxylethyl)methylammonium Methylsulfate Aqueous Solutions

We report herein a combined experimental-computational study on tris-(2-hydroxylethyl)methylammonium methylsulfate in water solutions, as a representative ionic liquid of the aqueous-solution behavior of hydroxylammonium-based ionic liquids. Relevant thermophysical properties were measured as a function of mixture composition and temperature. Classical molecular dynamics simulations were performed to infer microscopic structural features. The reported results for ionic liquid in water-rich solutions show that it behaves as isolated non-interacting ions solvated by water molecules, through well-defined solvation shells, exerting a disrupting effect on the water hydrogen bonding network. Nevertheless, as ionic liquid concentration increase, interionic association increases, even for diluted water solutions, evolving from the typical behavior of strong electrolytes in solution toward large interacting structures. For ionic-liquid-rich mixtures, water exerts a minor disrupting effect on the fluid's structuring because it occupies regions around each ion (developing water-ion hydrogen bonds) but without significantly weakening anion-cation interactions.

Screening ionic liquids as suitable ammonia absorbents on the basis of thermodynamic and kinetic analysis

Different ionic liquids (ILs) have been checked as potential ammonia absorbents at near-ambient temperatures and atmospheric pressure. In a first stage, the task-specific ILs 1-2(-hydroxyethyl)-3-methylimidazolium tetrafluoroborate [EtOHmim][BF4], choline bis(trifluoromethylsulfonyl)imide [choline][NTf2], tris(2-hydroxyethyl)methyl-ammonium methylsulfate [MTEOA][MeOSO3] and 1-(2-hydroxyethyl)-3-methylimidazolium dicyanamide [EtOHmim][DCA] were selected as potential high-capacity ammonia solvents by quantum-chemical COSMO-RS analysis. Then, they were experimentally tested considering both thermodynamic and kinetic aspects. Absorption kinetics was described by a phenomenological diffusion model. The desorption curves were also obtained. Finally, an efficiency criterion based on absorption–desorption cycles was established to simultaneously consider the kinetics and thermodynamics of the phenomena for the solvent selection. As a result, we propose a set of ILs with adequate properties to be used as absorbents for ammonia separation.

Water effect on CO2 absorption for hydroxylammonium based ionic liquids: A molecular dynamics study

The effect of water content on CO2 absorption in 2-hydroxyethyl-trimethylammonium L-(+)-lactate and tris(2-hydroxyethyl)methylammonium methylsulfate ionic liquids was studied using classical molecular dynamics simulations. The analysis of structural and dynamic properties, together with the energy contributions, showed that molecular-level structuring of CO2–ionic liquids is not affected by the presence of water molecules. Ion–water interactions are developed while maintaining the previous fluids’ structuring. The predicted dynamic properties show decreasing molecular mobility, that should lead to increasing viscosity upon water addition for the studied concentration range. Nevertheless, water has a moderate effect on CO2 transport within the studied hydroxylammonium fluids.

Enhanced stability and activity of cellulase in an ionic liquid and the effect of pretreatment on cellulose hydrolysis

We discuss the hydrolysis of cellulose using a pure cellulase: endo-1,4-β-D-glucanase (EG) from the fungus, Aspergillus niger, in buffer, the pure ionic liquid (IL), tris-(2-hydroxyethyl)-methylammonium methylsulfate (HEMA), and various mixtures of the two at different temperatures. Steady-state fluorescence and absorbance studies were performed to monitor the stability and activity of EG using cellulose azure as the substrate. EG attains its highest activity at 45°C in buffer and denatures at ∼55°C. On the other hand, HEMA imparts substantial stability to the enzyme, permitting the activity to peak at 75°C. The relative roles of temperature, viscosity, pH, polarity, and the constituent ions of the ILs on the hydrolysis reaction are examined. It is demonstrated that pretreatment of cellulose with ILs such as BMIM Cl, MIM Cl, and HEMA results in more rapid conversion to glucose than hydrolysis with cellulose that is not pretreated. The percent conversion to glucose from pretreated cellulose is increased when the temperature is increased from 45 to 60°C. Two different ILs are used to increase the efficiency of cellulose conversion to glucose. Cellulose is pretreated with BMIM Cl. Subsequent hydrolysis of the pretreated cellulose in 10-20% solutions of HEMA in buffer provides higher yields of glucose at 60°C. Finally, to our knowledge, this is the first study dealing with a pure endoglucanase from commercial A. niger. This enzyme not only shows higher tolerance to ILs, such as HEMA, but also has enhanced thermostability in the presence of the IL.