High Solvent Concentrations Research Articles

Synthesis and Characterization of Porogen Based Porous Low-k Thin Films

The present work is focused towards the lowering of the k value of deposited SiO2 thin films by varying solvent concentration i.e. ethanol in the range 4-10 ml. Porous low-k thin films were synthesized by using the sol-gel spinon technique. A non-ionic surfactant polysorbate 80 (Tween 80) was used as a porogen to generate the porosity in the film matrix. The lower values of refractive index and film density were measured to be 1.19 and 0.94 gm/cm3 respectively for 10 ml solvent concentration. Further, the lowest k value of 2.2 and highest porosity percentage of 58.5 % were obtained for the same film due to the dilution of coating solution at higher solvent concentration. The water contact angle of the film was observed to be increased to 106.3° which indicates the transformation of the deposited film surface from hydrophilic to hydrophobic. The change in chemical structure as an effect of solvent concentration is studied by using FTIR. From FTIR spectra the disappearance of Si-OH groups at higher solvent concentration reveals the increase in condensation rate. Overall in this study, the result shows the significant change in structural, chemical and optical properties of the deposited films at 10 ml solvent concentration. Such deposited porous thin films with lower k value and enhanced hydrophobicity can be used as an interlayer dielectric (ILD) for back end of line (BEOL) in CMOS technology.

Kinetics of Horseradish Peroxidase-Catalyzed Nitration of Phenol in a Biphasic System.

The use of peroxidase in the nitration of phenols is gaining interest as compared with traditional chemical reactions. We investigated the kinetic characteristics of phenol nitration catalyzed by horseradish peroxidase (HRP) in an aqueous-organic biphasic system using n-butanol as the organic solvent and NO2- and H2O2 as substrates. The reaction rate was mainly controlled by the reaction kinetics in the aqueous phase when appropriate agitation was used to enhance mass transfer in the biphasic system. The initial velocity of the reaction increased with increasing HRP concentration. Additionally, an increase in the substrate concentrations of phenol (0-2 mM in organic phase) or H2O2 (0-0.1 mM in aqueous phase) enhanced the nitration efficiency catalyzed by HRP. In contrast, high concentrations of organic solvent decreased the kinetic parameter Vmax/Km. No inhibition of enzyme activity was observed when the concentrations of phenol and H2O2 were at or below 10 mM and 0.1 mM, respectively. On the basis of the peroxidase catalytic mechanism, a double-substrate ping-pong kinetic model was established. The kinetic parameters were KmH2O2= 1.09 mM, KmPhOH = 9.45 mM, and Vmax = 0.196 mM/min. The proposed model was well fit to the data obtained from additional independent experiments under the suggested optimal synthesis conditions. The kinetic model developed in this paper lays a foundation for further comprehensive study of enzymatic nitration kinetics.

High-level expression and biochemical characterization of a novel cold-active lipase from Rhizomucor endophyticus

To identify novel cold-active lipases from fungal sources and improve their production by heterologous expression in Pichia pastoris. A novel cold-active lipase gene (ReLipB) from Rhizomucor endophyticus was cloned. ReLipB was expressed at a high level in Pichia pastoris using high cell-density fermentation in a 5-l fermentor with the highest lipase activity of 1395U/ml. The recombinant lipase (RelipB) was purified and biochemically characterized. ReLipB was most active at pH 7.5 and 25°C. It was stable from pH 4.5-9.0. It exhibited broad substrate specificity towards p-nitrophenyl (pNP) esters (C2-C16) and triacylglycerols (C2-C12), showing the highest specific activities towards pNP laurate (231U/mg) and tricaprylin (1840U/mg), respectively. In addition, the enzyme displayed excellent stability with high concentrations of organic solvents including cyclohexane, n-hexane, n-heptane, isooctane and petroleum ester and surfactants. A novel cold-active lipase from Rhizomucor endophyticus was identified, expressed at a high level and biochemically characterized. The high yield and unique enzymatic properties make this lipase of some potential for industrial applications.

First characterization of extremely halophilic 2-deoxy-D-ribose-5-phosphate aldolase

2-Deoxy-d-ribose-5-phosphate aldolase (DERA) catalyzes the aldol reaction between two aldehydes and is thought to be a potential biocatalyst for the production of a variety of stereo-specific materials. A gene encoding DERA from the extreme halophilic archaeon, Haloarcula japonica, was overexpressed in Escherichia coli. The gene product was successfully purified, using procedures based on the protein’s halophilicity, and characterized. The expressed enzyme was stable in a buffer containing 2 M NaCl and exhibited high thermostability, retaining more than 90% of its activity after heating at 70 °C for 10 min. The enzyme was also tolerant to high concentrations of organic solvents, such as acetonitrile and dimethylsulfoxide. Moreover, H. japonica DERA was highly resistant to a high concentration of acetaldehyde and retained about 35% of its initial activity after 5-h’ exposure to 300 mM acetaldehyde at 25 °C, the conditions under which E. coli DERA is completely inactivated. The enzyme exhibited much higher activity at 25 °C than the previously characterized hyperthermophilic DERAs (Sakuraba et al., 2007). Our results suggest that the extremely halophilic DERA has high potential to serve as a biocatalyst in organic syntheses. This is the first description of the biochemical characterization of a halophilic DERA.

Burkholderia cepacia lipase is a promising biocatalyst for biofuel production.

Lipases resistant to inhibition and denaturation by methanol are valuable tools for biotechnological applications, in particular for biofuel production. Microbial lipases have attracted a great deal of interest because of their stability at high concentrations of organic solvents. Burkholderia cepacia lipase (BCL) is tested here for robustness towards methanol in terms of conformational stability and catalytic activity in transesterification assays. This lipase turns out to be even more tolerant than the homologous and better characterized enzyme from Burkholderia glumae. BCL unfolding transition, as monitored by far-UV circular dichroism (CD) and intrinsic fluorescence, displays a Tm above 60°C in the presence of 50% methanol. The protein unfolds at low pH, and the organic solvent affects the nature of the denatured state under acidic conditions. The protein performs well in transesterification assays upon prolonged incubations at high methanol concentrations. BCL is highly tolerant to methanol and displays particularly high conformational stability under conditions employed for transesterification reactions. These features depict BCL as a promising enzyme for biofuel industry.

Organosolv pretreatment of sorghum bagasse using a low concentration of hydrophobic solvents such as 1-butanol or 1-pentanol.

BackgroundThe primary components of lignocellulosic biomass such as sorghum bagasse are cellulose, hemicellulose, and lignin. Each component can be utilized as a sustainable resource for producing biofuels and bio-based products. However, due to their complicated structures, fractionation of lignocellulosic biomass components is required. Organosolv pretreatment is an attractive method for this purpose. However, as organosolv pretreatment uses high concentrations of organic solvents (>50 %), decreasing the concentration necessary for fractionation would help reduce processing costs. In this study, we sought to identify organic solvents capable of efficiently fractionating sorghum bagasse components at low concentrations.ResultsFive alcohols (ethanol, 1-propanol, 2-propanol, 1-butanol, and 1-pentanol) were used for organosolv pretreatment of sorghum bagasse at a concentration of 12.5 %. Sulfuric acid (1 %) was used as a catalyst. With 1-butanol and 1-pentanol, three fractions (black liquor, liquid fraction containing xylose, and cellulose-enriched solid fraction) were obtained after pretreatment. Two-dimensional nuclear magnetic resonance analysis revealed that the lignin aromatic components of raw sorghum bagasse were concentrated in the black liquor fraction, although the major lignin side-chain (β-O-4 linkage) was lost. Pretreatment with 1-butanol or 1-pentanol effectively removed p-coumarate, some guaiacyl, and syringyl. Compared with using no solvent, pretreatment with 1-butanol or 1-pentanol resulted in two-fold greater ethanol production from the solid fraction by Saccharomyces cerevisiae.ConclusionsOur results revealed that a low concentration (12.5 %) of a highly hydrophobic solvent such as 1-butanol or 1-pentanol can be used to separate the black liquor from the solid and liquid fractions. The efficient delignification and visible separation of the lignin-rich fraction possible with this method simplify the fractionation of sorghum bagasse.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0427-z) contains supplementary material, which is available to authorized users.

Activity and conformation of lysozyme in molecular solvents, protic ionic liquids (PILs) and salt-water systems.

Improving protein stabilisation is important for the further development of many applications in the pharmaceutical, specialty chemical, consumer product and agricultural sectors. However, protein stabilization is highly dependent on the solvent environment and, hence, it is very complex to tailor protein-solvent combinations for stable protein maintenance. Understanding solvent features that govern protein stabilization will enable selection or design of suitable media with favourable solution environments to retain protein native conformation. In this work the structural conformation and activity of lysozyme in 29 solvent systems were investigated to determine the role of various solvent features on the stability of the enzyme. The solvent systems consisted of 19 low molecular weight polar solvents and 4 protic ionic liquids (PILs), both at different water content levels, and 6 aqueous salt solutions. Small angle X-ray scattering, Fourier transform infrared spectroscopy and UV-vis spectroscopy were used to investigate the tertiary and secondary structure of lysozyme along with the corresponding activity in various solvation systems. At low non-aqueous solvent concentrations (high water content), the presence of solvents and salts generally maintained lysozyme in its native structure and enhanced its activity. Due to the presence of a net surface charge on lysozyme, electrostatic interactions in PIL-water systems and salt solutions enhanced lysozyme activity more than the specific hydrogen-bond interactions present in non-ionic molecular solvents. At higher solvent concentrations (lower water content), solvents with a propensity to exhibit the solvophobic effect, analogous to the hydrophobic effect in water, retained lysozyme native conformation and activity. This solvophobic effect was observed particularly for solvents which contained hydroxyl moieties. Preferential solvophobic effects along with bulky chemical structures were postulated to result in less competition with water at the specific hydration layer around the protein, thus reducing protein-solvent interactions and retaining lysozyme's native conformation. The structure-property links established in this study are considered to be applicable to other proteins.

Highly Solvent Tolerance in Serratia marcescens IBBPo15

ABSTRACT The aim of this study was to investigate the solvent tolerance mechanisms in Serratia marcescens strain IBBPo15 (KT315653). Serratia marcescens IBBPo15 exhibited remarkable solvent-tolerance, being able to survive in the presence of high concentrations (above 40%) of toxic organic solvents, such as cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. S. marcescens IBBPo15 produced extracellular protease and the enzyme production decreased in cells exposed to 5% cyclohexane, n-hexane, toluene, styrene, and ethylbenzene, as compared with the control and n-decane exposed cells. S. marcescens IBBPo15 cells produced carotenoid pigments and alteration of pigments profile (i.e., phytoene, lycopene) were observed in cells exposed to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. The exposure of S. marcescens IBBPo15 cells to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, ethylbenzene induced also changes in the intracellular (e.g., 50 kDa protein) and extracellular (e.g., 39, 41, 43, 53, 110 kDa proteins) proteins profile. Significant RAPD, ARDRA, rep-PCR and PCR pattern modifications were not observed in DNA extracted from S. marcescens IBBPo15 cells exposed to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. Though only HAE1 and acrAB genes were detected in the genome of S. marcescens IBBPo15 cells, the unspecific amplification of other fragments being observed also when the primers for ompF and recA genes were used.

Enhanced production and organic solvent stability of a protease from Brevibacillus laterosporus strain PAP04.

A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media.

Shape instability on swelling of a stretched nematic elastomer filament.

Liquid crystalline elastomers combine the ordering properties of liquid crystals with elasticity of crosslinked polymer networks. In monodomain (permanently aligned) elastomers, altering the orientational (nematic) order causes changes in the equilibrium sample length, which is the basis of the famous effect of large-amplitude reversible mechanical actuation. The stimulus for this effect could be a change in temperature, or illumination by light in photosensitized elastomers, but equally the nematic order changes by mixing with a solvent. This work theoretically investigates a competition between the spontaneous contraction on swelling of a monodomain nematic elastomer and the externally imposed stretching. We find that this competition leads to bistability in the system and allows a two-phase separation between a nematic state with lower swelling and an isotropic state with higher solvent concentration. We calculated the conditions in which the instability occurs as well as the mechanical and geometric parameters of equilibrium states. Being able to predict how this instability arises will provide opportunities for exploiting nematic elastomer filaments.

Cloning, heterologous expression, and enzymatic characterization of a novel glucoamylase GlucaM from Corallococcus sp. strain EGB

The gene encoding a novel glucoamylase (GlucaM) from the Corallococcus sp. strain EGB was cloned and heterologous expressed in Escherichia coli BL21(DE3), and the enzymatic characterization of recombinant GlucaM (rGlucaM) was determined in the study. The glucaM had an open reading frame of 1938 bp encoding GlucaM of 645 amino acids with no signal peptide. GlucaM belongs to glycosyl hydrolase family 15 and shares the highest identity 96% with the GH15 glucoamylase of Corallococcus coralloides DSM 2259. The rGlucaM with His-tag was purified by the Ni2+-NTA resin, with a specific activity from 3.4 U/mg up to 180 U/mg, and the molecular weight of rGlucaM was approximately 73 kDa on SDS-PAGE. The Km and Vmax of rGlucaM for soluble starch were 1.2 mg/mL and 46 U/mg, respectively. rGlucaM was optimally active at pH 7.0 and 50 °C and had highly tolerance to high concentrations of salts, detergents, and various organic solvents. rGlucaM hydrolyzed soluble starch to glucose, and hydrolytic activities were also detected with amylopectin, amylase, glycogen, starch (potato), α-cyclodextrin, starch (corn and potato). The analysis of hydrolysis products shown that rGlucaM with α-(1–4),(1–6)-D-glucan glucohydrolase toward substrates. These characteristics indicated that the GlucaM was a new member of glucoamylase family and a potential candidate for industrial application.

Effect of Buffering System on Acetone-Butanol-Ethanol Fermentation by Clostridium acetobutylicum ATCC 824 using Pretreated Oil Palm Empty Fruit Bunch

Change of pH has been identified as the most significant parameter in modulating the transition between the conversions of acids into solvents in acetone-butanol-ethanol (ABE) fermentation by Clostridia. Thus, ABE fermentation at various phosphate buffer concentrations and initial pH values was conducted using pure glucose and sugars derived from pretreated oil palm empty fruit bunch (OPEFB). A higher solvent concentration (2.93 g/L) was obtained in the fermentation using 20 g/L of glucose with buffer compared with one without buffer that produced 1.34 g/L of solvents. Approximately 8.77 and 9.15 g/L of solvents were produced from fermentation using 40 g/L of glucose with and without buffer, respectively. In the latter conditions, at an initial pH of 5.5, 8.77 g/L of solvents was obtained, which was the highest concentration compared to other initial pH values. Increasing the buffer concentration to 0.2 M at an initial pH of 6.0 resulted in acid accumulation of 16.83 g/L but reduced the solvent production to 1.36 g/L. In addition, ABE fermentation using 20 g/L of sugars from pretreated OPEFB produced 2.25 g/L of solvents with a yield of 0.13 g/g, which was comparable with fermentation using 20 g/L of glucose conducted in a buffering system.

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AmyM, a Novel Maltohexaose-Forming α-Amylase from Corallococcus sp. strain EGB.

A novel α-amylase, AmyM, was purified from the culture supernatant of Corallococcus sp. strain EGB. AmyM is a maltohexaose-forming exoamylase with an apparent molecular mass of 43 kDa. Based on the results of matrix-assisted laser desorption ionization-time of flight mass spectrometry and peptide mass fingerprinting of AmyM and by comparison to the genome sequence of Corallococcus coralloides DSM 2259, the AmyM gene was identified and cloned into Escherichia coli. amyM encodes a secretory amylase with a predicted signal peptide of 23 amino acid residues, which showed no significant identity with known and functionally verified amylases. amyM was expressed in E. coli BL21(DE3) cells with a hexahistidine tag. The signal peptide efficiently induced the secretion of mature AmyM in E. coli. Recombinant AmyM (rAmyM) was purified by Ni-nitrilotriacetic acid (NTA) affinity chromatography, with a specific activity of up to 14,000 U/mg. rAmyM was optimally active at 50°C in Tris-HCl buffer (50 mM; pH 7.0) and stable at temperatures of <50°C. rAmyM was stable over a wide range of pH values (from pH 5.0 to 10.0) and highly tolerant to high concentrations of salts, detergents, and various organic solvents. Its activity toward starch was independent of calcium ions. The Km and Vmax of recombinant AmyM for soluble starch were 6.61 mg ml(-1) and 44,301.5 μmol min(-1) mg(-1), respectively. End product analysis showed that maltohexaose accounted for 59.4% of the maltooligosaccharides produced. These characteristics indicate that AmyM has great potential in industrial applications.

Degradation of morphine and codeine by gamma radiation in methanol solution

Abstract The high concentrations of opiate and solvent in wastewater are toxic to biological life and affect the aquatic environment. Therefore, it must be treated by an advanced treatment process such as ionizing radiation. Effect of organic media on morphine and codeine during gamma irradiation was determined for the first time in this paper. Samples were irradiated at ambient temperature and in air environment at various doses (0, 10, 20, 30, 40, 50 and 60 kGy). Gamma irradiation-induced changes in the molecular structure of morphine and codeine were monitored by direct infusion electrospray ionization mass spectrometry in positive ion mode. The mass of the by-products were appeared to be more than the mass of the original alkaloids. Molecular structures of the by-products and reaction pathways were proposed. Oxygenated morphine and oxygenated codeine were identified in the presence of oxygen. However, solvent radical addition reactions were observed as the main mechanism for the by-product formation in oxygen-free irradiation. The results indicated that 89% of morphine and 98% of codeine were degraded at dose of 50 kGy. In addition, alkaloids and their by-products were not detected above 50 kGy. Here, we demonstrated that ionizing radiation process is a promising method to remove morphine and codeine in solvent/opiate rich industrial wastewater.

Bacillus subtilis spore display of laccase for evolution under extreme conditions of high concentrations of organic solvent.

Protein libraries were displayed on the spore coat of Bacillus subtilis, and this method was demonstrated as a tool for directed evolution under extreme conditions. Escherichia coli, yeast, and phage display suffer from protein folding, and viability issues. On the other hand, spores avoid folding concerns by the natural sporulation process, and they remain viable under harsh chemical and physical environments. The naturally occurring B. subtilis spore coat protein, CotA, was evolved for improved activity under conditions of high organic solvent concentrations. CotA is a laccase, which is a copper-containing oxidase enzyme. A CotA library was expressed on the spore coat, and ∼ 3000 clones were screened at 60% dimethyl sulfoxide (DMSO). A Thr480Ala variant (Thr480Ala-CotA) was identified that was 2.38-fold more active than the wild-type CotA. In addition, Thr480Ala-CotA was more active with different concentrations of DMSO ranging from 0 to 70%. The mutant was also found to be more active compared with the wild-type CotA in different concentrations of methanol, ethanol, and acetonitrile.

Nile Red staining of phytoplankton neutral lipids: species-specific fluorescence kinetics in various solvents.

Nile Red (NR) staining potentially offers a simple method for monitoring lipid accumulation in microalgal cultivation. However, variable staining efficiencies and methods have been reported. The effect of dimethyl sulfoxide (DMSO), ethylene glycol (EG) and glycerol on NR penetration with four different phytoplankton species representing different taxonomical groups was studied. Treatment with the solvents enhanced the NR fluorescence of the diatom Phaeodactylum tricornutum during kinetic fluorescence measurements, but high concentrations of solvents were needed. None of the solvents improved NR staining of the green alga Chlorella pyrenoidosa and Scenedesmus obliquus, which are known to be difficult to stain due to their thick and rigid cell walls. The naked Isochrysis sp. cells stained best without solvents. The results confirm that NR staining protocol needs to be optimized for each species.

Characterization of a yeast recombinant laccase rLAC-EN3-1 and its application in decolorizing synthetic dye with the coexistence of metal ions and organic solvents

The recombinant laccase rLAC-EN3-1 was purified from Pichia pastoris in which the laccase gene lac-En3-1 from Ganoderma sp.En3 was successfully expressed. The properties of the purified rLAC-EN3-1 were studied. rLAC-EN3-1 showed strong stability under the alkaline conditions. rLAC-EN3-1 also exhibited strong resistance to some enzyme inhibitors such as SDS and EDTA. The effect of various metal ions on the laccase activity of rLAC-EN3-1 was investigated. rLAC-EN3-1 could tolerate very high concentrations of CuSO4, MnSO4 and MgSO4 (100mM). The effect of different organic solvents on the activity and stability of rLAC-EN3-1 was also determined. rLAC-EN3-1 had a very strong ability to tolerate some organic solvents widely used in the industry such as glycerin, ethylene glycol, butanediol. The results of decolorization test indicated that rLAC-EN3-1 had a strong capacity for decolorizing malachite green with the coexistence of high concentrations of different metal ions and organic solvents. Organic solvents tested in this study had little impact on the decolorization capability of rLAC-EN3-1. In addition, decolorized dye showed much lower toxicity to Pleurotus ostreatus than the original dye. Above advantages of rLAC-EN3-1 suggested that this laccase had a great potential and promising application value in the field of environmental biotechnology.

Purification and characterization of two thermostable laccases from Pycnoporus sanguineus and potential role in degradation of endocrine disrupting chemicals

In this study, the purification and characterization of two thermostable laccases produced by Pycnoporus sanguineus CS43 (LacI and LacII) were performed. Also, their biotechnological potential was assessed through the degradation of endocrine disrupting chemicals (EDCs). Laccases were purified by ultrafiltration, ion exchange (IEX) and hydrophobic interaction chromatography achieving specific activities close to 285 U mg -1 . The molecular weights of LacI and LacII, determined by SDS-electrophoresis, were 68 and 66 kDa, respectively. Both laccases showed high amino acid sequence similarity (91%) between them and high thermostability, at 50 and 60 °C (half-lives of 277.7 and 18 h for LacI, 35.8 and 2.25 h for LacII). The isoforms oxidized common laccase substrates such as 2,2′-azino-bis (3-ethylbenzthiazoline-6- sulfonate (ABTS), 2,6-dimethoxyphenol (DMP) and guaiacol at acidic pH conditions. ABTS was the most efficient substrate, showing high specificity constants of 74,816 and 36,746 mM -1 s -1 for Lac I and LacII, and Michaelis constants (K m ) of 6.9 and 12.2 μM respectively at pH 3. Both purified laccases remained active at high concentrations of organic solvents (acetonitrile, ethanol and acetone), with an IC 50 (v/v) of >64%, 55% and 47% for LacI, and 33%, 52% and 31% for LacII, respectively. LacI and LacII were tested to degrade EDCs, nonylphenol and triclosan, with more than 95% removal after 8 h of treatment with 100 U/L at pH 5 as determined by means of HPLC. The high thermostability, unique Michaelis-Menten kinetic parameters, and organic solvent tolerance demonstrated for the isoforms produced by P. sanguineus CS43 render them promising candidates for industrial applications. LacI exerted a higher thermal and pH stability, tolerance against inhibitors and was a more efficient catalyst for ABTS and DMP than LacII. © 2014 The Authors.

Ion pairing in protic ionic liquids probed by far-infrared spectroscopy: effects of solvent polarity and temperature.

The cation-anion and cation-solvent interactions in solutions of the protic ionic liquid (PIL) [Et3NH][I] dissolved in solvents of different polarities are studied by means of far infrared vibrational (FIR) spectroscopy and density functional theory (DFT) calculations. The dissociation of contact ion pairs (CIPs) and the resulting formation of solvent-separated ion pairs (SIPs) can be observed and analyzed as a function of solvent concentration, solvent polarity, and temperature. In apolar environments, the CIPs dominate for all solvent concentrations and temperatures. At high concentrations of polar solvents, SIPs are favored over CIPs. For these PIL/solvent mixtures, CIPs are reformed by increasing the temperature due to the reduced polarity of the solvent. Overall, this approach provides equilibrium constants, free energies, enthalpies, and entropies for ion-pair formation in trialkylammonium-containing PILs. These results have important implications for the understanding of solvation chemistry and the reactivity of ionic liquids.