Nonpolar Organic Solvents Research Articles

Self-Assembly of Surfactants in Non-Polar Organic Solvents

Self-Assembly of Surfactants in Non-Polar Organic Solvents

A Metallogel Based on a Zwitterionic Spirocyclic Meisenheimer Complex: Sensing of Fluoride Ions in Water and Moisture Content in Organic Solvents

AbstractDesign and synthesis of stimuli‐responsive materials are highly desired for various practical applications. For this purpose, a picric acid and N,N′‐dicyclohexylcarbodiimide based highly rigid zwitterionic spirocyclic Meisenheimer complex has been applied to produce a metallogel. The Meisenheimer complex does not undergo self‐gelation under any condition. But it forms a stable gel only with Fe3+ ion in a 2:1 ratio in chloroform. Interestingly, the Meisenheimer complex shows bright yellow emission under 366 nm UV light. But the Fe3+ based metallogel does not show any emission under UV irradiation. However, in the presence of fluoride contaminated water, the metallogel surface shows bright yellow emission while checking inside a UV chamber. Thus the non‐fluorescent metallogel was utilized as a sensor of aqueous fluoride ion. The sensor is able to detect aqueous fluoride down to 156 ppb concentration. Like the gel, the dried metallogel solution is also non‐fluorescent in different polar as well as nonpolar organic solvent. But the same solution shows bright yellow emission in the presence of water. The fluorescence intensity was found to increase with an increase in the percentage of water. In this way, the xerogel was utilized as a sensor of undesired water content present in different organic solvents which can detect moisture content with a minimum detection limit of 0.04% for dichloromethane.

Magnetite nanoparticles coat around activated γ-alumina spheres: A case of novel protection of moisture-sensitive materials against hydration

Protection of various materials against hydration is of continuing interest to chemists and material scientists. We report on stabilization of porous surface of activated γ-alumina spheres (AAS) against hydration by an adhesive coat of nano-magnetite particles. The nano-Fe3O4-coated AAS were prepared in the ultrasound-agitated suspension of magnetite nanoparticles in heptane and were characterized by using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area analysis and X-ray photoelectron spectroscopy (XPS). It is deduced that nanoparticle-alumina bonding interaction in non-polar organic solvent is enhanced by van der Waals attractive forces and that sonication induces changes in alumina morphology only in regions of contact between alumina and magnetite nanoparticles. The coated AAS submerged in still water avoid hydration and remain permeable by small gaseous (N2) molecules, while those soaked in moving water lose part of their coat and undergo hydration. The pristine and the coated AAS were briefly compared for their ability to degrade model antibiotics by using LC-MS analysis. It is confirmed that the degradation of trimethoprim is more efficient on the coated AAS. Our results are challenging for further research of Coulombic interactions between nano-particles and appropriate solid supports.

Oxonium Salts in the Synthesis and Spectral Behavior of Pyrano(pyrylium)‐mono methine Cyanine Dyes

Pyrano‐ and pyrylium mono‐8[4(1)] and/or 5(6)‐[2(4)]methine cyanine dyes (6a–k, 7a–f) were synthesized based on acyclic heterocyclic Schiff bases of pyrolo[3,2‐d]pyrazole[oxazole(imidazol‐6‐one)]‐1‐ium iodide salts, 5‐acetyl‐N‐aryl[pyrazolinyl(pyridinyl)]pyrolo‐[5,4‐d]pyrazolin‐iodide salts, and/or (anhydro bases) precursors (1a–i, 2a–I, 3a–i, 4a–i, and 5A,Ba–i). The structure of pyrylium‐9‐chloride and/or iodide and their pyrano(pyrylium)‐mono‐8[4(1)] and 5(6)[2(4)]methine cyanine dyes was identified by elemental and spectral data. The absorption spectra of some selected dyes were investigated in 95% EtOH, polar (nonpolar) organic solvents and in universal buffer solutions to investigate the optimal conditions for the application of such dyes as photosensitizers.

Superhydrophobic Polypropylene Functionalized with Nanoparticles for Efficient Fast Static and Dynamic Separation of Spilled Oil from Water.

Frequent oil spills not only threaten the ecosystem, but they are also a waste of a valuable source of energy. There is an urgent need to develop materials that can readily remove spilled oil from water bodies and also have the capacity to collect it for energy applications. Herein, a superhydrophobic fiber of functionalized polypropylene is engineered with the help of palmitic acid interaction with incorporated copper oxide nanoparticles. The successful development of functionalized polypropylene is confirmed by Fourier‐transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and energy‐dispersive X‐ray spectroscopy. The scanning electron microscopy images reveal that the surface roughness of the polypropylene is enhanced after functionalization. The optimized functionalized polypropylene displays an ultrahydrophobic surface with a water contact angle of 162.42°. The functionalized polyprolyene displays good absorption capacity. It has the capacity to take 30 to 40 times its own weight in oils and nonpolar organic solvents, which makes it useful for small spills. With a flux of 11 204 Lm−2 h−1, functionalized polypropylene is as an ideal material for the dynamic separation of oil spills from water. It also has excellent selectivity towards oil, water rejection, and oil absorption capacity.

Development of a Hyphenated Method Called DLLME/TLM for Trace Analysis of Cd

Dispersive Liquid-Liquid Microextraction / Thermal Lens Microscopy (DLLME/TLM) was developed as a new combination method for preconcentration and determination of Cd. Thermal Lens Microscopy is suitable for the determination of analyte after DLLME because of the low volume of the remained phase after DLLME and increasing of the enhancement factor for the nonpolar organic solvents. Some effective parameters on the micro extraction, complex formation and combination were selected and optimized. Under optimum conditions, the calibration graphs were linear in the range of 0.05-20 µg/L with the detection limit of 0.008 µg/L. The Relative Standard Deviation (RSD) for 1 and 10 µg/L of cadmium was 3.1 and 2.3, respectively. The enhancement factor of 1200 was obtained from a sample volume of 10.0 mL. DLLME/TLM method was applied to the analysis of real samples. The accuracy of the method was proved by using standard reference materials and micro spectrophotometry.

Superwettable antibacterial textiles for versatile oil/water separation

AbstractA gas‐phase deposition process based on the combination of nanoparticles (NPs) and thin films is developed to obtain either superhydrophobic or superamphiphilic nanocomposite coatings on filtration membranes. Superhydrophobic membranes are produced on nonwoven viscose fabric and they demonstrate selective absorption of nonpolar organic solvents from oil/water mixtures. Superamphiphilic membranes are produced on carbon cloth and found suitable for smart separation of light oil or heavy oil from water, with the efficiency above 99.97%. Incorporation of Cu NPs endow both types of the membranes with antibacterial properties. A twofold reduction in the metabolic activity of Escherichia coli is achieved after 24 hr of the incubation, which proves this environmentally friendly approach to be perspective for the development of multifunctional porous substrates.

Dissolved Methane Harvesting Using Omniphobic Membranes for Anaerobically Treated Wastewaters

Dissolved biomethane in anaerobic effluents has long been a hurdle for energy harvesting through anaerobic wastewater treatment processes. Here, we present a novel membrane process for dissolved methane recovery through the normal range of domestic wastewater temperatures by utilizing an omniphobic (nonwetting) microporous membrane. In a process driven by a solubility gradient, dissolved methane is extracted from a methane-rich aqueous solution (feed), transported across the omniphobic membrane, and absorbed into a nonpolar organic solvent (draw) that has a high solubility for methane. We fabricated the omniphobic membrane by coating a microporous polymeric membrane with silica nanoparticles, followed by surface fluorination. Using the omniphobic membrane, we demonstrate that nearly ≥90% of dissolved methane is recovered from methane-saturated feedwater at 15, 25, and 35 °C, simulating anaerobic effluents produced in the psychrophilic to mesophilic temperature range, while negligible transport of water is...

Molecular Insights into Water Clusters Formed in Tributylphosphate-Di-(2-ethylhexyl)phosphoric Acid Extractant Systems from Experiments and Molecular Dynamics Simulations.

Di-(2-ethylhexyl)phosphoric acid (D2EHPA) and tributylphosphate (TBP) are two of the most studied and researched organophosphorous extractants. D2EHPA is an acidic extractant, offering both hydrogen bond donor and acceptor sites while TBP, a neutral extractant, only offers a single acceptor site per molecule. In spite of this, it is observed that 1 M D2EHPA in dodecane is a poorer extractant for water than 1 M TBP in dodecane. The objective of present work is to look into the molecular interactions that cause such behavior. Experiments were carried out with varying molar ratios of TBP and D2EHPA in the organic dodecane phase. Total extractant concentration was kept constant at 1 M with dodecane as diluent. Water extraction was quantified by measuring the moisture content of the organic phase after equilibration. 1H and 31P NMR spectra of the organic phase samples were recorded to study the change in the chemical environment upon extraction. Small angle X-ray scattering data of water saturated extractant phases were analyzed for the possibility of a reverse micellar aggregate formation. Molecular dynamics simulations could calculate free energies in quantitative agreement with experiments. Experimental and simulation studies showed that aggregation in the organic phase was promoted by the presence of water. This combined approach, of experiments and simulation, has shown that water is indispensable for the formation of ordered aggregates of extractants in nonpolar organic solvents. It is seen that, in the organic phase, around 80% of water's hydrogen bonds are with extractant molecules rather than with itself. The analysis clearly indicates that, rather than forming an aqueous core surrounded by extractant, water acts as a bridge between extractant molecules.

Chemical Isolation, Quantification, and Separation of Skin Lipids from Reptiles.

Reptiles signal to conspecifics using lipids in their skin, primarily to enable mate tracking and assessment. The isolation of these lipids has utility in research focused on evolutionary patterns and mechanisms of chemical communication, in addition to understanding the waterproofing role of lipids in the evolution of terrestrial life. In an applied approach, such skin-based cues have potential use for wildlife managers dealing with invasive species. The main steps for quantifying reptile skin lipids in the protocol presented here include extraction, total lipid determination, and fractionation via column chromatography, the latter process resulting in purified eluates of compounds which can then either be analyzed to assign compound identifications (e.g., gas chromatography-mass spectrometry [GC-MS]) and/or used directly in more refined bioassays. Skin lipids can be extracted from living skin, shed skin, or dead whole animals, using nonpolar organic solvents (e.g., hexane, benzene, toluene). Extraction solubilizes the lipids and, then, the solvent can be evaporated to yield a measurable lipid-only extract. Fractionation involves the separation of the total lipid extract into specific eluates via traditional column chromatography. The total lipid extract is first bound to a substrate-based column (e.g., alumina) and, then, individual eluates ("fractions") of solvent at specific volumes are passed sequentially through the column to elute sets of compounds from the lipid mixture based on common polarity. The fractions progress in polarity at a standardized sequence by increasing the relative amount of polar solvent (e.g., diethyl ether) in nonpolar solvent. In this manuscript, we describe several methods for extracting skin lipids of reptiles and, then, provide a standard protocol for isolating different sets of compounds based on polarity, using traditional column chromatography. Whole lipid extracts or specific fractions can, then, be used in bioassays to determine any biological activity elicited by the compounds therein.

Analytical Response of Sensor Arrays Based on Photonic Crystals: Measurements of Diffuse Reflectance

Organic sensor arrays based on photonic crystals of submicrometer polystyrene particles, coated by a layer of polydimethylsiloxane, were studied using diffuse reflectance spectroscopy. The spectral characteristics obtained on instruments with different measurement geometries are compared. The conditions for obtaining the most informative analytical signal of sensor arrays based on photonic crystals are selected. Under the proposed conditions, the kinetic differences in the operation of these arrays upon exposure to nonpolar organic solvents (toluene and o-xylene) are compared. The work was performed at the Division of Analytical Chemistry, Department of Chemistry, Moscow State University.

Synthesis and Characterization of Low Molecular Weight Organogelators Derived from Amide Derivatives of N-acetylglycine

Six new N-acetylglycine amides and bisamides were prepared by reacting N-acetylglycine with different isocyanates including, hexamethylene diisocyanate, bis(4-isocyanatophenyl)methane, toluene 2,4-diisocyanate, 1,3-bis(2-isocyanatopropan-2-yl)benzene, phenyl isocyanate and 2-naphthyl isocyanate to furnish amides 1-6. The gelation ability of compounds (1-6) was investigated using fourteen different solvents including polar, non-polar organic solvents. Only compound 1 solidified toluene. Characterization of compounds (1-6) was done using spectroscopic methods, HRESI-MS, FTIR, 1H- and 13C-NMR. The morphology of toluene organogel (as xerogel) was determined through scanning electron microscopy (SEM).

Modified Correlation for Low-Density Polyethylene (LDPE) Solubility in Several Organic Solvents

A nonideal solubility equation is developed based on crystallinity and is applied to model the solid-liquid equilibrium for crystalline low-density polyethylene (LDPE) in a set of pure and blended nonpolar organic solvents experimentally at 338–379 K and atmospheric pressure. The polymer concentration ranges from 0.5 to 35 g in 100 mL solvent. Modified correlation based on the heat of fusion and the melting temperature was attained by using SSPS software based on experimental data. The ideal solubility and nonideal solubility equations were applied with two different regular methods for activity coefficient calculation, which do not correlate with the experimental data in large. The data collected from developed nonideal equation and modified correlation were found in good agreement with experimental data.

A facile method to prepare polymer functionalized carbon dots inspired by the mussel chemistry for LED application

We developed a simple way to prepare the polymer functionalized N-doping carbon dots (CDs) inspired by the mussel chemistry for white LED application. The N-doping CDs were decorated by catechol-terminated hydrophilic poly(poly(ethylene glycol) methyl ether methacrylate (PPEGMA) and hydrophobic polystyrene (PS) through Schiff base condensation/Michael addition reaction (CD@PEGMA and CD@PS), which owns two advantages: (1) polymer anchored CDs improved the optical properties of pure CDs; (2) hydrophobic PS could transfer hydrophilic CDs into nonpolar organic solvents to expand the application range of water-soluble CDs. The white-light bulk nanohybrid was obtained via in-situ polymerization of styrene monomers containing CD@PS as blue component and 5-(2-methacryloyl-ethyloxymethyl)-8-quinolinol (MQ) coordinated CdSe/ZnS quantum dots (QDs) as green and red components. The warm white light-emitting diode (WLED) was also fabricated based on the white bulk nanomaterials with CIE coordinate (0.32, 0.31) and the correlated color temperature 6250 K.

Magneto-Optical Properties of the Magnetite-Graphene Oxide Composites in Organic Solvents.

Graphene oxide (GO) aqueous solutions are known to form liquid crystals that can switch in electric fields. Magnetic fields as external stimuli are inefficient toward GO because of its diamagnetic properties, and GO is known to be insoluble in most of the organic solvents. In this study, composites of GO with oleate-protected magnetite nanoparticles were prepared as stable colloid solutions in the mixed isopropanol-chloroform solvents. The structure of the composite particles and the optical properties of their solutions can be controlled by the ratio of the mixing parent components. The as-prepared solutions are highly responsive to external magnetic field. As the consequence, the optical transmission and the direction of light scattering can be efficiently manipulated. These systems pave the way for fabricating functional materials, such as magneto-optical switches, density-gradient materials, and micromotors. Solubility in nonpolar organic solvents broadens the scope of their potential applications.

Molecular mechanism of enzyme tolerance against organic solvents: Insights from molecular dynamics simulation

Biocatalysis in presence of organic solvents has numerous industrially attractive advantages in comparison to traditional aqueous solvents. In some cases, the presence of organic molecules such as methanol in the processes such as enzymatic production of biodiesel is inevitable. However, enzyme inactivation and/or instability in organic solvents limits such biotechnological processes. Although it was found that some enzymes are more and others are less tolerant against organic solvents, the structural basis of such differences is relatively unknown. In this work, using molecular dynamics simulations, we have investigated the structural behavior of enzymes with completely different structural architecture including lipase, laccase and lysozyme in the presence of methanol as polar and hexane as non-polar organic solvents. In agreement with the previous experimental observations, simulations showed that lipase is more tolerant against both polar and non-polar organic solvents. It is found that lipase has high stability in pure hexane even higher than that obtained in the aqueous solvent. In contrast, laccase shows better stability in the aqueous conditions. To obtain general mechanism of enzyme inactivation in the presence of methanol and hexane, we have treated lysozyme as model enzyme in the different percentages of these solvents in long MD simulations. It is found that lysozyme is completely denatured at high concentration- of methanol, but it remains native at low concentration of this solvent. Interestingly, the concentration-dependence structural behavior of enzyme was completely different in the presence of hexane. It was obtained that low concentrations of hexane may impose more instability on the enzyme conformation than higher percentages. Results also showed that presence of water is determining factor in the enzyme stability at high concentrations of hexane. Pure hexane may also lead to the surface denaturation of the enzymes. Both methanol and hexane denaturation mechanisms were initiated by diffusion of organic solvent in hydrophobic core. However, enzyme denaturation in hexane was continued by a collapse of hydrophobic core and entering hexane molecules to the core, but in methanol it was completed by decomposition of the secondary structures. In both cases it was found that beta structures are more prone to destabilize than helix structures. This may be a reason for obtained results about lower stability of laccase with β-barrel architecture than lipase with multiple helixes at it surface. In total, by our extensive structural data, it was found that the forces which stabilize tertiary structure have pivotal role in enzyme tolerance against both polar and non-polar organic solvents.

Poly(ionic liquid)s as phase-transporter for graphene oxide liquid crystals from aqueous to non-polar organic phase via noncovalent functionalization

ABSTRACTWe synthesise a novel poly(ionic liquid) (PIL) and develop a procedure that allows the phase transfer of graphene oxides (GO) from water to organic solvent, retaining graphene oxide liquid crystal (GOLC) phase in various organic solvents, especially non-polar organic solvents. PIL ([PEP-MIM]DBS) is exploited in this procedure as a noncovalent functional material that is capable of transporting GO from aqueous to non-polar organic phase. PILs can decorate GO noncovalently and keep GO nano-sheets exfoliated in solid-state PILs/GO hybrids, which can well redisperse in organic solvents without any agglomeration. This expands the number of known solvents which can support GOLC phase to dimethyl formamide, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, and a number of other non-polar organic solvents, many of which were not known to afford GOLC phase prior to this report, such as dichloromethane, tetrachloromethane, dichloroethane and tetrachloroethane.

A Novel Method of Affinity Tag Cleavage in the Purification of a Recombinant Thermostable Lipase from Aneurinibacillus thermoaerophilus Strain HZ

The development of an efficient and economical purification method is required to obtain a pure and mature recombinant protein in a simple process with high efficiency. Hence, a new technique was invented to cleave the tags from the N-terminal region of recombinant fusion HZ lipase in the absence of protease treatment. The recombinant pET32b/rHZ lipase was overexpressed into E. coli BL21 (DE3). Affinity chromatography was performed as the first step of purification. The stability of the protein was then tested in different temperatures. The fused Trx-His-S-tags to the rHZ lipase was cleaved by treatment of the fusion protein at 20 °C in 100 mM Tris-HCl buffer, pH 8.0. The precipitated tag was removed, and the mature recombinant enzyme was further characterized to specify its properties. A purification yield of 78.9% with 1.3-fold and 21.8 mg total purified mature protein was obtained from 50 mL starting a bacterial culture. N-terminal sequencing of purified recombinant HZ lipase confirmed the elimination of the 17.4 kDa tag from one amino acid before the native start codon (Methionine) of the protein. The mature rHZ lipase was highly active at 65 °C and a pH of 7.0, with a half-life of 2 h 15 min at 55 °C and 45 min at 60 °C. The rHZ lipase showed a preference for the hydrolysis of natural oil with a long carbon chain (C18) and medium-size acyl chain p-nitrophenyl esters (C10). The enzyme remained stable in the presence of nonpolar organic solvents, and its activity was increased by polar organic solvents. This study thus demonstrates a simple and convenient purification method which resulted in the high yield of mature enzyme along with unique and detailed biochemical characterization of rHZ lipase, making the enzyme favorable in various industrial applications.

Crystalline 2D Covalent Organic Framework Membranes for High-Flux Organic Solvent Nanofiltration.

Two-dimensional (2D) covalent organic framework (COF) materials have the most suitable microstructure for membrane applications in order to achieve both high flux and high selectivity. Here, we report the synthesis of a crystalline TFP-DHF 2D COF membrane constructed from two precursors of 1,3,5-triformylphloroglucinol (TFP) and 9,9-dihexylfluorene-2,7-diamine (DHF) through the Langmuir-Blodgett (LB) method, for the first timed. A single COF layer is precisely four unit cells thick and can be transferred to different support surfaces layer by layer. The TFP-DHF 2D COF membrane supported on an anodic aluminum oxide (AAO) porous support displayed remarkable permeabilities for both polar and nonpolar organic solvents, which were approximately 100 times higher than that of the amorphous membranes prepared by the same procedure and similar to that for the best of the reported polymer membranes. The transport mechanism through the TFP-DHF 2D COF membrane was found to be a viscous flow coupled with a strong slip boundary enhancement, which was also different from those of the amorphous polymer membranes. The membrane exhibited a steep molecular sieving with a molecular weight retention onset (MWRO)of approximately 600 Da and a molecular weight cutoff (MWCO)of approximately 900 Da. The substantial performance enhancement was attributed to the structural change from an amorphous structure to a well-defined ordered porous structure, which clearly demonstrated the high potential for the application of 2D COFs as the next generation of membrane materials.

Development and validation of an assay method for benzene in the delgocitinib drug substance using conventional HPLC

Benzene is a highly toxic solvent that should be limited to no more than 2 ppm in drug substances, as regulated by the International Council for Harmonization guideline Q3C. We herein report an assay method for residual benzene detection in the delgocitinib drug substance using conventional high-performance liquid chromatography (HPLC). The proposed method takes advantage of the good extraction efficiency of benzene when using non-polar organic solvents, the ability of benzene to concentrate in minimum amounts of organic solvent, and the high solubility of the delgocitinib drug substance in aqueous media, resulting in salt formation as well as excellent sensitivity and selectivity. Specifically, this method uses 5 mL of 8 mol/L potassium hydroxide as an aqueous medium and 1 mL of n-hexane as organic solvent, in order to increase the resolution and sensitivity to residual benzene for HPLC. Range of the method was from 0.5 to 3 ppm according to the results of linearity, accuracy and precision, and limits of detection and quantitation of the method were 0.1 and 0.5 ppm, respectively. We expect this method to be used as a general and convenient assay of excellent sensitivity and selectivity for benzene detection, particularly when contained in water-soluble drug substances.