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Aramid nanofibers (ANFs) have received considerable attention due to their high mechanical properties, low density, and ability to be manufactured through upcycling. In response, research on the dispersion of ANFs in organic solvents is essential for adoption in a wider range of applications. In this study, efficient strategies are proposed to overcome the current shortcomings, which are long processing time and small yield, and obtain a never-dried bulk homogeneous ANF dispersion in organic solvents through a series of facile steps, which is expected to assist and broaden applications such as nanofiber-reinforced composites, additives, coatings, and membranes. [ABSTRACT FROM AUTHOR]

Removal of organic solvents (such as chloroform, toluene, etc.) in trace amounts using adsorbents from water is a challenge due to their low removal efficiencies and poor selectivities. Herein, four polysulfates (P1-P4) with different flexible group embedded backbones were synthesized via a sulfur fluoride exchange (SuFEx) reaction, and their swelling behaviors in organic solvents were investigated. P1 with a flexible ethyl group on its backbone can selectively swell in aprotic organic solvents with medium and high polarities about 30-fold its original weight, which is much higher than that of P4 with rigid benzene on its backbone. Moreover, molecular dynamic (MD) simulation results showed that the swelling mechanism could be put down to the electrostatic and van der Waals forces between the polysulfates and organic solvents. Surprisingly, the polysulfates can be used to remove chloroform and toluene from water with removal efficiencies of up to 99.26 and 99.42%, respectively. Furthermore, the polysulfates also exhibited high selectivities and anti-interference performances toward chloroform in the presence of other pollutants and different acid/base environments. Our work provides a strategy to construct adsorbents with high efficiencies for removal of low concentrations of organic solvents from water.

Herein, we successfully synthesized a magnetic mesoporous material, Fe3O4@SiO2@mSiO2, and acetylcholinesterase (AChE) was immobilized by a covalent bonding method. The tolerance ability of immobilized AChE (by magnetic mesoporous silica nanoparticles) in different organic solvents was better than that of free AChE. Furthermore, the magnetic character of the fixed AChE improved the detection sensitivity and reliability for carbofuran, methomyl, isoprocarb, and carbaryl. The limit of detection (LOD) of carbofuran, methomyl, isoprocarb, and carbaryl was 0.01, 0.22, 0.26, and 0.43 μM, respectively. It shows a good correlation between carbamate pesticides (CMs) and the inhibition rate of Fe3O4@SiO2@mSiO2-AChE in a given concentration range. The linear ranges of carbofuran, methomyl, isoprocarb, and carbaryl were 0.02–0.90, 0.31–12.33, 0.27–5.17, and 0.50–14.91 μM, respectively. Chinese cabbage and cucumber spiked with four CMs were used as field-incurred samples to prove the feasibility of the developed method. According to the maximum residue limits, the results were satisfactory, with recovery rates between 77.03 and 110.07%, and the RSDs ranged from 3.17 to 6.79%. The stability of immobilized AChE in organic solvents was improved with enhanced sensitivity for detecting pesticide residues. [ABSTRACT FROM AUTHOR]

Exposure of electrospray droplets to organic vapors was shown to dramatically reduce alkali-metal adduction on protein ions and shift protein charge states. Since DESI-MS is affected by similar adduct species as ESI-MS and shares similar ionization mechanisms, polar organic vapor additives should likewise also improve the DESI-MS analysis of proteins. Here the DESI spray was exposed to a variety of polar organic vapor additives. Head space vapors of polar organic solvents were entrained in nitrogen gas and delivered to the atmosphere inside a semi-enclosed plastic enclosure surrounding the spray plume. The vapors of acetone, acetonitrile, ethyl acetate, methanol, and water were investigated. Vapor dependent effects were observed with respect to changes in protein charge state distributions and signal intensities. With ethyl acetate vapor addition, the signal intensities of all proteins investigated were significantly increased, including proteins larger than 25 kDa such as carbonic anhydrase II and bovine serum albumin. [ABSTRACT FROM AUTHOR]

Herein, a study on a new lower critical solution temperature (LCST) polymer in an organic solvent by an electrochemical technique has been reported. The phase-transition behavior of poly(arylene ether sulfone) (PAES) was examined on 1,2-dimethoxyethane (DME). At a temperature above the LCST point, polymer molecules aggregated to create polymer droplets. These droplets subsequently collided with an ultramicroelectrode (UME), resulting in a new form of staircase current decrease. The experimental collision frequency and collision signal were analyzed in relation to the concentration of the polymer. In addition, the degree of polymer aggregation associated with temperature change was also observed. [ABSTRACT FROM AUTHOR]

Calcium sulfate is one of the most important construction materials. Today it is employed as high-performance compound in medical applications and cement mixtures. We report a synthesis for calcium sulfate nanoparticles with outstanding dispersibility properties in organic solvents without further functionalization. The nanoparticles (amorphous with small γ-anhydrite crystallites, 5-50 nm particle size) form long-term stable dispersions in acetone without any sign of precipitation. 1H NMR spectroscopic techniques and Fourier-transform infrared spectroscopy (FTIR) reveal absorbed 2-propanol on the particle surfaces that induce the unusual dispersibility. Adding water to the nanoparticle dispersion leads to immediate precipitation. A phase transformation to gypsum via bassanite was monitored by an in situ kinetic FT-IR spectroscopic study and transmission electron microscopy (TEM). The dispersibility in a volatile organic solvent and the crystallization upon contact with water open a broad field of applications for the CaSO4 nanoparticles, e.g., as nanogypsum for coatings or the fabrication of hybrid composites. [ABSTRACT FROM AUTHOR]

Oxidosqualene cyclase (OSC), a membrane-associated protein, is a key enzyme of sterol biosynthesis. Here we report a novel assay for OSC, involving reaction in aqueous solution, NMR quantification in organic solvent, and factor analysis of spectra. We evaluated one known and three novel inhibitors on OSC of Trypanosoma cruzi, a parasite causative of Chagas disease, and compared their effects on human OSC for selectivity. Among them, one novel inhibitor showed a significant parasiticidal activity. [ABSTRACT FROM AUTHOR]

The solubility of florfenicol form A in eight pure organic solvents (propionic acid, ethanol, 1-propanol, 1-butanol, 2-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol, and 2-ethyl-1-hexanol) and three binary solvents (dimethyl sulfoxide + ethanol, dimethyl sulfoxide + 1-propanol, and dimethyl sulfoxide + 1-butanol) was measured by a laser dynamic method at temperature from 283.15 to 323.15 K. The experimental results show that the mole fraction solubility of florfenicol in the pure solvents decreased according to the following order: ethanol > 1-propanol > 2-propanol > 1-butanol > 3-methyl-1-butanol > 2-methyl-1-propanol ≈ propionic acid > 2-ethyl-1-hexanol. The experimental results show that the mole fraction solubility of florfenicol form A in the binary solvents increased with the increase of temperature and dimethyl sulfoxide mass fraction. The experimental solubility data were well correlated with the four thermodynamic models: modified Apelblat equation, Λh equation, NRTL model equation, and Wilson model equation. The modified Apelblat model equation was regarded as the best one to fit the experimental values in the pure solvents. [ABSTRACT FROM AUTHOR]

The finding that triggering the redox activity of oxygen ions within the lattice of transition metal oxides can boost the performances of materials used in energy storage and conversion devices such as Li-ion batteries or oxygen evolution electrocatalysts has recently spurred intensive and innovative research in the field of energy. While experimental and theoretical efforts have been critical in understanding the role of oxygen nonbonding states in the redox activity of oxygen ions, a clear picture of the redox chemistry of the oxygen species formed upon this oxidation process is still missing. This can be, in part, explained by the complexity in stabilizing and studying these species once electrochemically formed. In this work, we alleviate this difficulty by studying the phase Ba5Ru2O11, which contains peroxide O22– groups, as oxygen evolution reaction electrocatalyst and Li-ion battery material. Combining physical characterization and electrochemical measurements, we demonstrate that peroxide groups can easily be oxidized at relatively low potential, leading to the formation of gaseous dioxygen and to the instability of the oxide. Furthermore, we demonstrate that, owing to the stabilization at high energy of peroxide, the high-lying energy of the empty σ* antibonding O–O states limits the reversibility of the electrochemical reactions when the O22–/O2– redox couple is used as redox center for Li-ion battery materials or as OER redox active sites. Overall, this work suggests that the formation of true peroxide O22– states are detrimental for transition metal oxides used as OER catalysts and Li-ion battery materials. Rather, oxygen species with O–O bond order lower than 1 would be preferred for these applications. [ABSTRACT FROM AUTHOR]

An environmentally friendly and straightforward dehydration/rehydration method for glycerophospholipid mixing that avoids the use of organic solvents, cosolvents, or additives was developed. We prepared binary mixtures of zwitterionic and anionic glycerophospholipids using only deionized water in the entire mixing process. The resulting lipid films were subsequently reconstituted in vesicular form and compared to controls using differential scanning calorimetry. The calorimetric scans revealed no significant differences between mixing methods for any of the studied cases. These findings suggest that the developed dehydration/rehydration procedure creates a sample with equivalent compositional uniformity than the conventional solvent evaporation technique. [ABSTRACT FROM AUTHOR]

A room temperature based environmentally friendly aqueous solution synthesis route was developed to fabricate highly dispersed small SnO2 nanoparticles (3-5 nm) without the application of any pressurized reaction vessel or organic solvents. The subsequent treatments, that is, dialyzing and freezing, allow for the acquision of dual-function nanostructures with sheet-like feature and large aspect ratio except for the ordinary irregular aggregates. Dye-sensitized solar cells (DSCs) constructed with the resultant multifunctional SnO2 showed an outstanding photovoltaic conversion efficiency (PCE) of 6.92% and an unexpected JSC of 19.5 mA cm-2 at an optimized thickness of 14.1 μm. The excellent performance can be ascribed to the effective coordination of the favorable features (i.e., strong light scattering, large dye loading capability, and fast electron transport) via rational film thickness control as indicated by diffused reflectance spectra, UV-vis absorption spectra, and electrochemical impedance spectroscopy (EIS). [ABSTRACT FROM AUTHOR]

We present an all-atom molecular dynamics study of the effect of a range of organic solvents (dichloromethane, diethyl ether, toluene, methanol, dimethyl sulfoxide, and tetrahydrofuran) on the conformations of a nanogel star polymeric nanoparticle with solvophobic and solvophilic structural elements. These nanoparticles are of particular interest for drug delivery applications. As drug loading generally takes place in an organic solvent, this work serves to provide insight into the factors controlling the early steps of that process. Our work suggests that nanoparticle conformational structure is highly sensitive to the choice of solvent, providing avenues for further study as well as predictions for both computational and experimental explorations of the drug-loading process. Our findings suggest that when used in the drug-loading process, dichloromethane, tetrahydrofuran, and toluene allow for a more extensive and increased drug-loading into the interior of nanogel star polymers of the composition studied here. In contrast, methanol is more likely to support shallow or surface loading and, consequently, faster drug release rates. Finally, diethyl ether should not work in a formulation process since none of the regions of the nanogel star polymer appear to be sufficiently solvated by it. [ABSTRACT FROM AUTHOR]

For the first time liquid-liquid extraction was used for the preconcentration of heavy metals prior to their determination in water by microwave-induced plasma atomic emission spectrometry (MP-AES). Extraction of Pb(II), Cd(II), Co(II), Ni(II), Zn(II), and Cu(II) was performed in unconventional aqueous biphasic system (ABS) formed by addition of hydrophobic solid salt, namely, tetrahexylammonium bromide, to aqueous sample, with neither organic solvents nor salting-out agents being used. The metal ions were quantitatively recovered with 4-(2-pyridylazo)-resorcinol (PAR). The extract was diluted with ethanol/HCl and introduced directly into an MP-AES instrument. The factors influencing extraction (pH, reagent concentration, phase contact time, etc.) and MP-AES detection parameters were studied and optimized. For the developed method, limits of detection of 1.3, 4.9, 0.06, 1.2, 4.2, and 3.2 µg L-1 were obtained for cadmium, cobalt, copper, nickel, lead, and zinc, respectively, providing from 60- to 500-fold improvement as compared with the analysis without preconcentration. The method was applied for the analysis of two certified reference materials (CRM) of wastewater and surface water as well as the samples of well and seawater. Coupling MP-AES with ABS extraction significantly extends the capabilities of the method, especially for the analysis of high salinity waters. [ABSTRACT FROM AUTHOR]

Recently, the Eyring-modified two-suffix-margules (MTSM) model for calculating viscosities of ionic liquid mixtures was proposed by Atashrouz et al. (Atashrouz, S.; Zarghampour, M.; Abdolrahimi, S.; Pazuki, G.; Nasernejad, B. J. Chem. Eng. Data 2014, 59, 3691-3704). In this work, a simple modification of the Eyring-MTSM model was presented and applied to the viscosity calculation of binary mixtures of organic solvents. The accuracy of the modified model was assessed by comparing experimental viscosities at atmospheric pressure for 182 binary mixtures, and the overall average relative deviation (ARD) between the calculated results and literatures is 0.61%. In addition, the relationship between the parameters in the model and the boiling point of mixtures was established. Experimental viscosities containing 478 binary mixtures were used to evaluate the reliability of the relations, and good agreement was obtained between experimental and calculated values with ARD of 1.62%. Furthermore, the modified Eyring-MTSM model was extended to the viscosities of high pressures. The ARD is 1.61% for the high-pressure viscosities of 63 binary mixtures. The predictive ability of the model was also tested, and the model is suitable for the prediction of the homologous mixtures. [ABSTRACT FROM AUTHOR]

In this paper, the electrical conductivities of ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([BMIM][TFSI]) in mixed organic solvents of propylene carbonate (PC) + γ-butyrolactone (GBL) and ethylene carbonate (EC) + dimethyl carbonate (DMC) were measured. The effects of mixed organic solvents with different ratios (1:0, 2:1, 1:1, 1:2, 0:1) on the electrical conductivity of ionic liquid were investigated. The organic solvents EC and DMC have a synergistic effect for the electrical conductivity of [BMIM][TFSI]-EC/DMC, and the optimal ratio of EC to DMC is 1:1; however, the organic solvents have no synergistic effect in [BMIM][TFSI]-PC/GBL. The concentration dependence of the electrical conductivity of the solution can be well fitted by the empirical Casteel-Amis equation. The effects of temperature on electrical conductivity can be described by the Vogel-Tamman-Fulcher (VTF) equation and the Arrhenius equation. The IL concentration dependence of the activation energy Ea and the pre-exponential factor A in the Arrhenius equation were also investigated, and fitted by empirical equations. On the basis of the VTF equation and the Arrhenius equation, a quasi-Arrhenius equation was proposed to describe the effects of temperature and composition on the electrical conductivity simultaneously in binary systems and ternary systems, and the correlation results agree well with the experimental results. [ABSTRACT FROM AUTHOR]

Two-dimensional molecular crystals (2DMCs) are a promising candidate for flexible and large-area electronics. Their large-area production requires both low nuclei density and 2D crystal growth mode. As an emerging type of material, their large-area production remains a case-by-case practice. Here we present a general, efficient strategy for large-area 2DMCs. The method grows crystals on water surface to minimize the density of nuclei. By controlling the interfacial tension of the water/solution system with a phase transfer surfactant, the spreading area of the solvent increases tens of times, leading to the space-confined 2D growth of molecular crystals. As-grown sub-centimeter-sized 2DMCs floating on the water surface can be easily transferred to arbitrary substrates for device applications. [ABSTRACT FROM AUTHOR]

Slippery liquid-infused porous surfaces (SLIPS) have potential impact on a wide range of industries, including healthcare, food packaging, and automobile. A tremendouseffort has been focused on developing novel fabrication methods for making SLIPS. However, current fabrication methods usually involve harsh conditions and complicated postfabrication modifications or are limited to specific substrates. Presented here is a novel method for the fast and facile fabrication of SLIPS. Layer-by-layer (LBL) assembly of branched polyethylenimine and Nafion, a perfluorinated polyelectrolyte, is performed with methanol as the solvent. Hierarchically rough and superhydrophobic surface is obtained directly without further modification on various substrates. The surface properties are shown to highly depend on the LBL assembly parameters, including deposition cycles, dipping time, rinsing time, and drying time between baths. The polyelectrolyte multilayers obtained with this method are infused with Krytox 100 to form SLIPS surfaces, which show excellent omniphobic, antifouling, self-cleaning, flexible, and optical properties. The result of this study not only simplifies the fabrication of SLIPS surfaces, but also provides great insight for making LBL films with specific morphologies. [ABSTRACT FROM AUTHOR]

Room-temperature ionic liquids (ILs) composed of organic anions bis(trifluoromethanesulfonyl)imide (TFSI), bis(fluorosulfonyl)imide (FSI), and trifluoromethanesulfonate (OTf) exhibit interesting physical properties and are important for many electrochemical applications. TFSI and FSI form "hydrophobic" ILs, immiscible with water but miscible with many organic solvents and polymers; for computer simulation studies, it is thus essential to develop force fields for these anions that are transferable among this wide variety of chemical environments. In this work, we develop entirely ab initio force fields for the TFSI, FSI, and OTf anions and predict the properties of corresponding 1-butyl-3-methylimidazolium ILs. We discuss important subtleties in the force field development related to accurately modeling conformational flexibility, that is, relaxed torsional profiles and intramolecular electrostatic interactions. The TFSI anions have notable conformational flexibility in the IL, and we predict approximately 70% cisoid and 20% transoid conformations, which is largely driven by cation/anion ion-pair interactions and is opposite to the trend expected from the anion ab initio potential energy surface. The favorable interactions between the cation and cisoid TFSI conformations result in a shoulder in the cation/anion radial distribution function at short distances, whereas interconversion between cisoid and transoid conformations occurs on a commensurate time scale as ion diffusion processes. In addition to this physical insight on anion effects, we expect that these force fields will have important applications for studying a variety of complex electrolyte systems. [ABSTRACT FROM AUTHOR]

Proton NMR spectra are usually acquired using deuterated solvents, but in many cases it is necessary to obtain spectra on samples in protonated solvents. In these cases, the intense resonances of the protonated solvents need to be suppressed to maximize sensitivity and spectral quality. A wide range of highly effective solvent suppression methods have been developed, but additional measures are needed to suppress the 13C satellites of the solvent. Because the satellites represent 1.1% of the original solvent signal, they remain problematic if unsuppressed. The recently proposed DISPEL pulse sequences suppress 13C satellites extremely effectively, and this Technical Note demonstrates that combining DISPEL and presaturation results in exceptionally effective solvent suppression. An important element in the effectiveness is volume selection, which is inherent within the DISPEL sequence. Spectra acquired in protonated dimethlysulfoxide and tetrahydrofuran show that optimum results are obtained by modifying the phase cycle, cycling the pulse-field gradients, and using broadband 13C inversion pulses to reduce the effects of radiofrequency offset and inhomogeneity. [ABSTRACT FROM AUTHOR]

Nitrogen can be an inexpensive alternative to helium used by direct analysis in real time (DART), especially in consideration of the looming helium shortage. Therefore, the ionization mechanism of positive-ion N2 DART has been systematically investigated. Our experiments suggest that a range of metastable nitrogen species with a variety of internal energies existed and all of them were less energetic than metastable helium atoms. However, compounds with ionization energies (IE) equal to or lower than 10.2 eV (all organic compounds except the extremely small ones) can be efficiently ionized. Because N2 DART was unable to efficiently ionize ambient moisture and common organic solvents such as methanol and acetonitrile, the most important ionization mechanism was direct Penning ionization followed by self-protonation of polar compounds generating [M+H]+ ions. On the other hand, N2 DART was able to efficiently ionize ammonia, which was beneficial in the ionization of hydrogen-bonding compounds with proton affinities (PA) weaker than ammonia generating [M+NH4]+ ions and large PAHs generating [M+H]+ ions through proton transfer. N2 DART was also able to efficiently ionize NO, which led to the ionization of nonpolar compounds such as alkanes and small aromatics generating [M-(2m+1)H]+ (m=0,1…) ions. Lastly, metastable nitrogen species was also able to produce oxygen atoms, which resulted in increased oxygen adducts as the polarity of organic compounds decreased. In comparison with He DART, N2 DART was approximately one order of magnitude less sensitive in generating [M+H]+ ions, but could be more sensitive in generating [M+NH4]+ ions.ᅟ [ABSTRACT FROM AUTHOR]

In the present study, the solubility of limonin in eight organic solvents and a binary solvent system (ethyl acetate + 2-propanol) was determined by the high-performance liquid chromatography analysis method within the temperature range from 283.2 to 323.2 K. The results showed that the solubility of limonin increased with temperature in the eight pure solvents and the binary solvent mixtures. In the binary solvent system ethyl acetate + 2-propanol, the solubility decreased with the initial mole fraction of ethyl acetate. The experimental solubility of limonin was well correlated with temperature by the simplified thermodynamic equation, modified Apelblat equation, λh equation, and NRTL equation. Furthermore, the solubility of limonin in the binary solvent mixtures was correlated with both temperature and initial solvent composition of the binary solvent mixtures by the Jouyban-Acree model, van't Hoff-Jouyban-Acree model, modified Apelblat-Jouyban-Acree model, Ma model, Sun model, and NRTL model. Finally, the thermodynamic properties of the mixing process, including mixing Gibbs energy, mixing enthalpy, and mixing entropy, were also calculated. [ABSTRACT FROM AUTHOR]

Nanosecond transient absorption and theoretical calculations have been used to investigate the intermolecular hydrogen abstractions from alcohols and 1-naphthol by the lowest excited triplet (T1) of 1-chloro-4-nitronaphthalene upon excitation of the compound in organic solvents. The hydrogen abstraction of T1 from hydroxy group of 1-naphthol takes place through an electron transfer followed by a proton transfer through hydrogen bonding interaction with rate constants of ~109 M-1 s-1. Hydrogen-bonding is crucial in this process, indicated by the observation of a half reduction for T1 yield when increasing the concentration of 1-naphthol. The hydrogen abstraction in this way can be decelerated by increasing solvent polarity and hydrogen-bonding donor ability. The T1 of 1-chloro-4-nitronaphthalene can undergo one-step H atom abstraction from alkyl hydrogen in alcoholic solvents, with rate constants of ~104 M-1 s-1, and produce radical intermediates with the absorption maximum at 368 nm. DFT calculation results indicate both oxygens of the nitro group are active sites for hydrogen abstraction, and the difference of activation barriers for formation of two radical isomers is only 1.0 kcal/mol. [ABSTRACT FROM AUTHOR]

In this work, we develop fluorescent hierarchical nanofiber bundles 1, which involve the internanofiber hydrogen-bonding interactions, for rapid and sensitive detection of diethyl chlorophosphate (DCP) vapor. First, the internanofiber hydrogen-bonding strength can be weakened by photoexcitation, which thereby increases the internanofiber spacing and decreases the fluorescence intensity. Then, when exposed to trace DCP vapor, the strong interactions between DCP and hydroxyl groups on the nanofibers can effectively retighten the nanofibers and enhance the fluorescence as the detection signal. In contrast, the interferences, such as common organic solvents, cannot retighten nanofiber bundles 1 because of the lack of strong interactions with the nanofibers. On the basis of this novel detection mechanism, fluorescence detection of DCP with rapid signal response (ca. 3 s) and high sensitivity (15 ppb) is achieved. [ABSTRACT FROM AUTHOR]

Modified Separation of Cohesive Energy Density (MOSCED) is an attractive method for modeling phase-equilibria because it both can make quantitative predictions and give insight into the system's underlying molecular-level interactions. While MOSCED predicts satisfactory values of limiting activity coefficients of organics in water, we find that predicted limiting activity coefficients for water (here the solute) in organic solvents shows a much greater disparity with reference data. Moreover, the error is systematic and increases as the value of the limiting activity coefficient increases. After detailed assessment of the MOSCED parameters for water, we find this is not a limitation of the model but results from how the parameters were regressed. As a consequence, in the present study we reregress MOSCED parameters for water which greatly improves the accuracy with which MOSCED may predict limiting activity coefficients of water in organic solvents, with the average absolute error decreasing from 3056.2% to 63.2%. The improvement is systematic, increasing as the value of the limiting activity coefficient increases. We additionally demonstrate the ability of the revised parameters to make improved binary liquid-liquid equilibrium calculations in aqueous systems. [ABSTRACT FROM AUTHOR]

An axial-substituted silicon phthalocyanine derivative, SiPc(OR)2 (R = C4H9), that is soluble in organic solvent is conveniently synthesized. This silicon phthalocyanine derivative reacts with a hydroxyl group on a substrate and then with another phthalocyanine derivative under mild conditions. The accumulation number of the phthalocyanine molecules on the substrates is easily controlled by the immersion time. On the basis of AFM (atomic force microscopy) images, the surface of the phthalocyanine-modified glass substrate has uneven structures on the nanometer scale. ITO electrodes modified with the composition of the phthalocyanine derivative and PCBM show stable cathodic photocurrent generation upon light irradiation. [ABSTRACT FROM AUTHOR]

Sustainable solvents are a topic of growing interest in both the research community and the chemical industry due to a growing awareness of the impact of solvents on pollution, energy usage, and contributions to air quality and climate change. Solvent losses represent a major portion of organic pollution, and solvent removal represents a large proportion of process energy consumption. To counter these issues, a range of greener or more sustainable solvents have been proposed and developed over the past three decades. Much of the focus has been on the environmental credentials of the solvent itself, although how a substance is deployed is as important to sustainability as what it is made from. In this Review, we consider several aspects of the most prominent sustainable organic solvents in use today, ionic liquids, deep eutectic solvents, supercritical fluids, switchable solvents, liquid polymers, and renewable solvents. We examine not only the performance of each class of solvent within the context of the reactions or extractions for which it is employed, but also give consideration to the wider context of the process and system within which the solvent is deployed. A wide range of technical, economic, and environmental factors are considered, giving a more complete picture of the current status of sustainable solvent research and development. [ABSTRACT FROM AUTHOR]

Traditional organic synthesis relies heavily on organic solvents for a multitude of tasks, including dissolving the components and facilitating chemical reactions, because many reagents and reactive species are incompatible or immiscible with water. Given that they are used in vast quantities as compared to reactants, solvents have been the focus of environmental concerns. Along with reducing the environmental impact of organic synthesis, the use of water as a reaction medium also benefits chemical processes by simplifying operations, allowing mild reaction conditions, and sometimes delivering unforeseen reactivities and selectivities. After the "watershed" in organic synthesis revealed the importance of water, the development of water-compatible catalysts has flourished, triggering a quantum leap in water-centered organic synthesis. Given that organic compounds are typically practically insoluble in water, simple extractive workup can readily separate a water-soluble homogeneous catalyst as an aqueous solution from a product that is soluble in organic solvents. In contrast, the use of heterogeneous catalysts facilitates catalyst recycling by allowing simple centrifugation and filtration methods to be used. This Review addresses advances over the past decade in catalytic reactions using water as a reaction medium. [ABSTRACT FROM AUTHOR]

Solventless coated epoxysilicone composite membranes have been prepared from a UV curable epoxysilicone polymer for organic solvent nanofiltration. Coatings were conducted solventless on a roll-to-roll pilot line using a forward gravure coating technique, and applied on a polyacrylonitrile or cross-linked poly(ether imide) support. Cross-linking of the poly(ether imide) support membrane with propanediamine enhanced the adhesion properties of the epoxysilicone selective layer. Penetration of the coating solution into the porous support membrane was confirmed using scanning electron microscopy with energy-dispersive X-ray spectroscopy. Membranes fabricated using two different gravure heads have been studied, with submicrometer siloxane layer thicknesses achieved. The separation performance of the membranes is observed to be independent of the thickness. It has been possible to achieve membranes with a molecular weight cut-off < 500 g mol-1 in hydrocarbon solvents. Benefits of the fabrication include the ability to UV cross-link under air, elimination of solvent-based coating, and the feasibility of achieving uniform, submicrometer coatings at large scale manufacturing. These membranes comprise a further step toward greener and safer membrane production. [ABSTRACT FROM AUTHOR]

The ruthenium(II)-catalyzed, heteroatom-directed C-H arylation of indoles with arylsilanes in water has been developed. The method represents the first example of a ruthenium(II)-catalyzed oxidative C-H arylation in water/aqueous media as a sustainable solvent for C-H functionalization. The reaction enables the synthesis of a wide range of indoles with exquisite selectivity for arylation at the C-2 position. Preliminary mechanistic studies indicate reversibility of the C-H ruthenation step under the developed reaction conditions. [ABSTRACT FROM AUTHOR]

The solubility of dipyridamole p-toluene sulfonate in seven monosolvents (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutanol, 2-butanol) and three different binary solvents (methanol + ethanol, methanol + 1-propanol, methanol + 1-butanol) was measured by a gravimetric method at temperatures ranging from 288.15 to 328.15 K. The experimental results indicate that the solubility of dipyridamole p-toluene sulfonate increases with increasing temperature while showing negative correlation with the mole fraction of organic solvents (ethanol, 1-propanol, 1-butanol) at a given temperature in binary solvents. The Apelblat model, the CNIBS/R-K model, and the modified version of Jouyban-Acree models (the Apel-JA equation) were used to correlate the experimental data, and the calculated results of above models were found to agree well with the experimental data. [ABSTRACT FROM AUTHOR]

The dithioketal derivatives of industrially important, semicrystalline poly(arylene ether ketone)s undergo facile exchange with aliphatic diols in the presence of N-bromo-succinimide to give a range of novel poly(arylene ether ketal)s. These are amorphous and readily soluble in a wide range of organic solvents. Although generally stable under ambient conditions, they undergo rapid and quantitative hydrolysis in the presence of acids to regenerate the original polyketones. The poly(ether ketal)s reported here are not accessible from ketal-type monomers, nor can they be obtained by direct reaction of poly(ether ketone)s with aliphatic diols. The starting polyketones are essentially unchanged after sequential dithioketalization, dithioketal--ketal exchange, ketal hydrolysis, and redithioketalization. Poly(arylene ether ketal)s provide a new approach to the processing of poly(arylene ether ketone)s into carbon fiber composite materials. [ABSTRACT FROM AUTHOR]

For miniaturization and integration of chemical synthesis and analytics on small length scales, the development of complex lab-on-chip (LOC) systems is in the focus of many current research projects. While application specific synthesis and analytic modules and LOC devices are widely described, the combination and integration of different modules is intensively investigated. Problems for in-line processes such as solvent incompatibilities, e.g., for a multistep synthesis or the combination of an organic drug synthesis with a cellbased biological activity testing system, require a solvent exchange between serialized modules. Here, we present a continuously operating microfluidic solvent exchanger based on the principle of free-flow electrophoresis for miscible organic/ aqueous fluids. We highlight a proof-of-principle and describe the working principle for the model compound fluorescein, where the organic solvent DMSO is exchanged against an aqueous buffer. The DMSO removal performance could be significantly increased to 95% by optimization of the microfluidic layout. Moreover, the optimization of the inlet flow ratio resulted in a minimized dilution factor of 5, and we were able to demonstrate that a reduction of the supporting instrumentation is possible without a significant decrease of the DMSO removal performance. Finally, the compatibility of the developed solvent exchanger for cell based downstream applications was proven. The impedimetric monitoring of HEK293A cells in a continuously operating microfluidic setup revealed no adverse effects of the residual DMSO after the solvent replacement. Our solvent exchanger device demonstrates the power of micro-free-flow electrophoresis not only as a powerful technique for separation and purification of compound mixtures but also for solvent replacement. [ABSTRACT FROM AUTHOR]

Ratiometric fluorescence detection attracts much attention because of its decreased environmental influence and easy-to-differentiate color and intensity change. Herein, a guest-encapsulation metal-organic framework (MOF), Ru@MIL-NH2, is prepared with 2-aminoterephthalic acid, AlCl3, and Ru(bpy)32+ by a simple one-pot method for ratiometric fluorescence sensing of water in organic solvents. The rational selection of the excitation wavelength provides dual emission at 465 and 615 nm from Ru@ MIL-NH2 under a single excitation of 300 nm. High sensitivity, low detection limit (0.02% v/v), wide response range (0-100%), and fast response (less than 1 min) are obtained for ratiometric fluorescence sensing of water under single excitation with Ru@MIL-NH2 as the probe. Moreover, the result of water content is independent of the concentration of Ru@MIL-NH2 as the merit of ratiometric fluorescence detection. The response mechanism reveals that the protonation of the nitrogen atom of the MIL-NH2, the π-conjugation system, and the stable fluorescence of Ru(bpy)32+ achieve the ratiometric fluorescence. The analysis of real spirit samples confirms the proposed method. A test strip is prepared with Ru@MIL-NH2 for convenient use. We believe that such turn-on ratiometric host-guest MOFs and the rational selection of excitation wavelength will offer guidance for ratiometric fluorescence detection with wide applications. [ABSTRACT FROM AUTHOR]

The solubility of eight biologically active nonaromatic compounds with a common 3-thia-1-aza-bicyclo fragment in 1-octanol and hexane was determined in the temperature range of T = 293.15-315.15 K. The solubility of the substances in alcohol is approximately 2 orders of magnitude higher than in alkane and varies within 3.0 x 10-3 to 2.1 x 10-1 and 7.1 x 10-5 to 13.5 x 10-3 mol. fractions, respectively. In accordance with the structure of the substituent at the para position of the phenyl ring, the studied compounds are arranged in the following order of decreasing solubility in both solvents: methyl- > fluoro- > ethyl- > trifluoromethyl- > cyano- > acetyl-. The ideal solubility of the substances in 1-octanol, calculated from thermophysical parameters was found to correlate with the reported experimental data. The activity coefficients of the substances in saturated solutions of organic solvents are determined by the method of distribution between two liquid phases. The thermodynamic aspects of the relationship between the processes of dissolution, melting, sublimation, and solvation of the substances are discussed. [ABSTRACT FROM AUTHOR]

This work introduces photoactivated molecular layer deposition (pMLD) as a route to deposit organic nanoscale polymer films with molecular-level control. Surface-tethered acrylate polymers are obtained through a radical step-growth polymerization where a diene and a diiodo monomer, ethylene glycol dimethacrylate (EGM) and 1,3-diiodopropane (DIP), respectively, are sequentially dosed in the vapor-phase under pulsed UV irradiation. pMLD occurs with a constant growth rate of 3.7 Å/cycle, and both monomers display self-limiting saturation. Films deposited by pMLD exhibit excellent stability in organic solvents. Furthermore, annealing studies with in situ X-ray photoelectron spectroscopy (XPS) reveals thermal stability up to 350 °C in vacuum. The mechanism behind pMLD of EGM and DIP is proposed based on detailed characterization of the polymer films by XPS and Fourier transform infrared spectroscopy, growth modeling, and comparison with control studies of pMLD involving monofunctional precursors. The coupling chemistry of pMLD presented herein provides future possibilities to create apolar linkages in the formation of nanoscale organic films. [ABSTRACT FROM AUTHOR]

Organic solvent separations could revolutionize the field of separations by enabling new low energy, low carbon emission technologies. Microporous materials are potential game changers for these challenging separations due to their ability to provide superb size and shape discrimination; however, large-scale application of these materials has yet to be adopted. This critical perspective will discuss the current state of the art in the separation of similarly sized organic molecules via microporous membranes and provide key focus areas for future research. [ABSTRACT FROM AUTHOR]

NMR spectroscopy is currently a premier technique for structural elucidation of organic molecules. Quantitative NMR (qNMR) methodology has developed more slowly but is now widely accepted, especially in the areas of natural product and medicinal chemistry. However, many undergraduate students are not routinely exposed to this important concept. This article describes a simple and practical lab experiment that has been successfully performed by students in a Quantitative Analysis class for several years and is based on a comparison of relative integration areas of species present in spectra of compound mixtures. In this experiment, ¹ NMR spectroscopy is used to determine the purity of common organic solvents using dimethyl sulfoxide as an internal standard in D2O. Groups of students analyze unknown samples containing one of the following solvents: methanol, ethanol, 2-propanol, tetrahydrofuran, or acetone, to which water has been added as an impurity. Over a period of five years, 54 students analyzed samples ranging from 60% to 99% purity with an average error of 2.64%. This experiment fills a niche in the initial portion of a standard Quantitative Analysis lab sequence by differentiating between qualitative and quantitative analysis, providing exposure to equipment not usually encountered in an introductory analytical lab, and generating numerical data for students to analyze and evaluate. [ABSTRACT FROM AUTHOR]

The aim of this study is to prepare high-performance poly(p-phenylene) (PPP)-based polymer nanofiber belts. The hypothesis is that these nanofiber belts would possess high mechanical properties, excellent thermal and chemical resistances, and unique electrical and photoelectrical characteristics owing to high rigidity of macromolecular backbones. In general, the unsubstituted PPP polymers are infusible and insoluble in common organic solvents; thus, the synthesis and processing of these polymers are intractable. Although some substituted PPP-based polymers (i.e., PPP derivations) are soluble, their molecular weights are too low to be processed into nanofibers (particularly by the electrospinning technique). To date, there has been no report on the preparation of any kind of PPP-based polymer nanofibers. In this study, four soluble PPP-based oligomers of phthalate-capped poly(2,5-benzophenone) (PBPA) with varied molecular weights were synthesized via Ni(II) complex-catalyzed cross-coupling reaction; subsequently, the blend nanofiber belts of poly(2,5-benzophenone)-pyrrolone (PBPY) and polyimide (PI) were made by the combination of electrospinning and molecular coupling assembly techniques followed by heat treatment, wherein the use of poly(amic acid) (PAA, the precursor of PI) as carrier/glue polymer for assisting electrospinning is crucial for successful preparation of the nanofibers. The PBPY/PI nanofiber belts exhibited high mechanical strength, superior thermal stability, and chemical resistance; hence, they could be used as filtration media under high-temperature and/or corrosive conditions, and they could also be used as separators in batteries and supercapacitors. It is important to note that this is the first reported study on the preparation of PPP-based polymer nanofibers; additionally, this study also provides an innovative approach for making nanofibers from the polymers that cannot be electrospun directly. [ABSTRACT FROM AUTHOR]

Both chiral OFm monosubstituted cyclo(l-Glu-l-Glu) and cyclo(d-Glu-d-Glu) display a robust gelation ability in a variety of organic solvents and water. In contrast to an individual enantiomer, their racemate can form rapidly recoverable thixotropic hydrogels with a remarkably shorter thixotropic recovery time. This unexpected thixotropic behavior is induced by the random arrangement of d- and l-enantiomers in the cell units, leading to the formation of "pseudoracemate", noncrystalline self-assemblies in the resulting 3D fibrous network. [ABSTRACT FROM AUTHOR]

Still, the hydroamination of dienes to form allylic amines is a challenging task in a continuous operation. Herein, we present the performance of a membrane reactor by the implementation of a continuously operated hydroamination reaction of β-myrcene with morpholine. Via application of a poly ether-ether-ketone (PEEK) membrane, operation at elevated temperatures was possible in an integrated reaction/separation unit. First, the kinetics of the hydroamination reaction and relevant membrane characteristics were determined under optimized reaction conditions. Afterward, these results were incorporated in a reactor/separator model to predict the process behavior. With this, catalyst replenishment was adjusted resulting in stable continuous operation. In the end an increase of the turnover number from 460 to 5135 compared to a batch process was achieved. The desired geranyl amines were obtained in very good yields higher than 80%, while an excellent conversion of β-myrcene above 93% was reached in a long-time stable process. [ABSTRACT FROM AUTHOR]

An environmentally benign, copper-catalyzed diazidation of a broad range of olefins, including vinylarenes, unactivated alkenes, allene, and dienes, under mild conditions with TMSN3 (trimethylazidosilane) as azido source, has been developed. This reaction can be carried out in organic solvent or in aqueous solution where water is the sole solvent. The functional group compatibility of this reaction is good, which is proved by late-stage functionalizations of complex substrates. [ABSTRACT FROM AUTHOR]

Observation at the single molecule level has been a revolutionary tool for molecular biophysics and materials science, but single molecule studies of solution-phase chemistry are less widespread. In this work we develop an experimental platform for solution-phase single molecule force spectroscopy in organic solvents. This optical-tweezer-based platform was designed for broad chemical applicability and utilizes optically trapped core-shell microspheres, synthetic polymer tethers, and click chemistry linkages formed in situ. We have observed stable optical trapping of the core-shell microspheres in ten different solvents, and single molecule link formation in four different solvents. These experiments demonstrate how to use optical tweezers for single molecule force application in the study of solution-phase chemistry. [ABSTRACT FROM AUTHOR]

The solubilities of 3-nitrobenzonitrile in 12 organic solvents including methanol, ethanol, n-propanol, isopropanol, acetone, n-butanol, 2-methyl-1-propanol, acetonitrile, acetic acid, ethyl acetate, cyclohexane, and toluene were measured by the static method within the temperature range from (278.15 to 318.15) K under atmospheric pressure of 101.1 kPa. The mole fraction solubility of 3-nitrobenzonitrile in the selected solvents increased with a rise in temperature. In general, they ranked as acetone > (acetonitrile, ethyl acetate) > toluene > acetic acid > methanol > ethanol > n-propanol > n-butanol > isopropanol >2-methyl-1-propanol > cyclohexane. The achieved solubilities of 3-nitrobenzonitrile were correlated via the λh equation, modified Apelblat equation, NRTL model, and Wilson model. The maximum relative average deviation and root-mean-square deviation were 1.87% and 2.399 × 10-3, respectively. Finally, the mixing properties, e.g., change in Gibbs energy, enthalpy, entropy, activity coefficient at infinitesimal concentration, and reduced excess enthalpy, were also derived on the basis of the Wilson model. The mixing process of 3-nitrobenzonitrile in these solvents was endothermic and spontaneous. [ABSTRACT FROM AUTHOR]

Ionic liquids are considered green solvents and widely investigated. 1-Butyl-3-methylimidazolium chloride shows promise for making biofuels from biomass. In this work, the experimental densities of the binary mixtures, comprising ionic liquids of 1-butyl-3-methylimidazolium chloride and organic solvents (i.e., N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, and pyridine), are determined at atmospheric pressure (0.0967 MPa) from 303.15 to 353.15 K. The excess molar volumes are determined to understand the interaction between ionic liquid and organic solvents, and a Redlich-Kister type equation is used to describe the excess properties. Moreover, the derived volumetric properties of thermal expansion coefficients are calculated as well as the excess coefficients. [ABSTRACT FROM AUTHOR]

The solubility data of fosfomycin sodium (FOM-Na) in six pure solvents (methanol, ethanol, propanol, cyclohexane, acetone, N,N-dimethylformamide) and two binary solvents (methanol + ethanol, methanol + acetone) at temperatures ranging from 283.15 to 323.15 K were measured by a laser monitoring dynamic method at atmospheric pressure. It turned out that the solubility data decreased with increasing temperature, and also varies with the composition of the solvents. Moreover, the experimental data in pure solvents have been correlated with two thermodynamic models (i.e., modified Apelblat and van't Hoff), and the data in binary solvents have been correlated with CNIBS/R-K equation and two modified versions of Jouyban-Acree models (Van't-JA equation and Apel-JA equation), respectively. All the results showed a good agreement with the experimental data. Intermolecular interaction force and dielectric constants are introduced to explain the relationship between solubility and temperature. In addition, the analysis of the solubilities implies that higher temperature may destroy the forces between the solvent and solute molecules, leading to lower solubility. And this can give a guide to the design and optimization of the crystallization process of FOM-Na in the industry. [ABSTRACT FROM AUTHOR]

We focused on the solubility of olaparib under atmospheric pressure in isopropyl alcohol, MTBE, acetonitrile, and tetrahydrofuran as well as in the (tetrahydrofuran + MTBE, acetonitrile + isopropyl alcohol) mixtures from 280.35-319.35 K. It is found that the solubility of olaparib and temperature were positively correlated in the range of our study. We chose the modified Apelblat equation, the Buchowski-Ksiazaczak λh equation, CNIBS/R-K equation, and the Jouyban-Acree equation to verify the thermodynamic properties of olaparib. Computational results showed that all selected equations agreed well with the experimental data, and the modified Apelblat equation gives the best correlation. We also selected two binary solvent dissolution systems, and the test found that (tetrahydrofuran + MTBE) mixtures may be a good recrystallization system. This study provides valuable data for olaparib's production process purification. [ABSTRACT FROM AUTHOR]

The C40 carotenoid capsanthin is of photophysical interest because it belongs to the family of terminally carbonyl-substituted apocarotenes. These have the potential to exhibit intramolecular charge transfer (ICT) character in the excited state. We studied its ultrafast dynamics in different solvents using broadband transient absorption spectroscopy in the 260-1600 nm range. Photoexcitation initially populated the S2(1¹Bu+) state which decayed to the S1(2¹Ag-) state in 120-150 fs. The lifetime of the S1 state decreased from 10.3 ps (isooctane) to 9.1 ps (methanol). Together with the absence of stimulated emission this suggested a weak ICT character of S1. A steric influence of the five-membered ring in capsanthin was identified based on a comparison with the sister apocarotenone citranaxanthin which features methyl substitution at the keto group. While both apocarotenones exhibit the same S1 lifetime in isooctane, the decrease in lifetime in polar solvents is weaker for capsanthin because presumably the five-membered ring sterically perturbs stabilization of ICT character by the solvent. For the S1 state of capsanthin we further observed intramolecular vibrational redistribution and collisional energy transfer to the solvent with time constants of 340-420 fs and 8.5-9.1 ps, respectively. No evidence for excited-state photoisomerization of capsanthin was found. [ABSTRACT FROM AUTHOR]

The well-known Marangoni effect perfectly supports the dynamic mechanism of organic solvent-swollen gels on water. On this basis, we report a series of energy conversion processes of concentrated droplets of polyvinylidene fluoride/dimethyl formamide (PVDF/DMF) that can transfer chemical-free energy to kinetic energy to rapidly rotate itself on water. This droplet (22.2 mg) is capable to offer kinetic energy of 0.099 μJ to propel an artificial paper rocket of 31.8 mg to move over 560 cm on water at an initial velocity of 7.9 cm s-1. As the droplet increases to 35.0 mg, a paper goldfish of 10.6 mg can be driven to swim longer at a higher initial velocity of 20 cm s-1. The kinetic energy of the droplet can be further converted to electrical energy through an electromagnetic generator, in which as a 0.5 MΩ resistor is loaded, the peak output reaches 6.5 mV that corresponds to the power density of 0.293 μW kg-1. We believe that this report would open up a promising avenue to exploit energies for applications in miniature robotics. [ABSTRACT FROM AUTHOR]