Low-polarity Organic Solvents Research Articles

Characteristics of the existing methods for obtaining carotenes from carotenoid concentrates

Carotenes, which simultaneously have the properties of natural dyes and biologically active substances that have a positive effect on human health and life expectancy, are becoming increasingly widespread in the food, pharmacological and cosmetic industries. This necessitates an increase in the production of carotenes on an industrial scale. For use in food technologies, an encapsulated form of carotenes is recommended, which requires their high purity. The purpose of this study is to analyze domestic and foreign scientific, technical and patent information on existing methods for obtaining carotenes from carotenoid concentrates to determine the direction of research for the development of technology for the production of carotenes, in particular lycopene, ensuring the production of high purity lycopene from carotenoid concentrates, as well as increasing release of lycopene. The issues of using chromatographic methods for isolating lycopene, their advantages and disadvantages, as well as the use of non-polar and low-polar organic solvents for isolating lycopene from carotenoid concentrate are considered. The promising direction of research on the use of adsorption resins in the isolation of lycopene from carotenoid concentrates is noted.It has been concluded that the currently existing methods for obtaining carotenes from carotenoid concentrates, in particular lycopene, are quite technically complex and time-consuming. Some of the mallow the production of high purity lycopene, but the yield of lycopene is so low that their industrial scaling seems impractical. Taking this into account, research is being updated in the field of developing a technology for producing lycopene from a carotenoid concentrate, providing a high yield of high purity lycopene, with the possibility of its implementation on an industrial scale.

Temperature-dependent chlorosomal self-aggregation of bacteriochlorophyll-d analogs with a branched alkyl chain in a single 1-chlorooctane solvent

Abstract Recently, the supramolecular polymerization of chlorophyll pigments mimicking a natural light-harvesting apparatus (chlorosome) was demonstrated in low-polar organic solvents or aqueous solutions. To obtain the most aggregation models, a concentrated solution of the pigments in a polar organic solvent was diluted with a large amount of a nonpolar organic solvent or water. Here, bacteriochlorophyll-d analogs possessing branched alkyl chains of different lengths at the peripheral 17-propionate residue on the core chlorin π-system were prepared and their highly soluble chlorosomal supramolecules were produced in single 1-chlorooctane as a low-polar solvent. Temperature-dependent electronic absorption and circular dichroism spectroscopies were employed to analyze their self-aggregation and disaggregation mechanisms. The synthetic analogs were monomeric at high temperatures and self-aggregated during cooling of the hot solution through a non-sigmoidal pathway. The obtained chlorosomal self-aggregates were reversibly monomerized by heating the homogeneous solution. The disaggregation pathway was fitted to an isodesmic model whose melting points depended on the alkyl-chain lengths.

Highly Efficient Darzens Reactions Mediated by Phosphazene Bases under Mild Conditions.

The highly basic and poorly nucleophilic phosphazene base P1‐t‐Bu promotes the Darzens condensation of α‐halo esters with aromatic aldehydes affording α,β‐epoxy esters in nearly quantitative yields under mild conditions and in short reaction times. The more basic P4‐t‐Bu phosphazene was found useful with low reactivity aldehydes. These reactions can be performed in aprotic organic solvents of low polarity, thus minimizing the hydrolysis of α,β‐epoxy esters which often accompanies the base‐promoted Darzens condensations.

Cross-Linked Polymeric Gels and Nanocomposites: New Materials and Phenomena Enabling Technological Applications

Cross-linked gels are synthesized by homo- and copolymerization of functionalized acrylamides. The gels swell in aqueous solution, and some of them (e.g., poly(N-isopropylacrylamide (PNIPAM)) also in organic solvents of low polarity (e.g., dichloromethane), making the gels amphiphilic materials. Nanocomposites can be made by dispersing nanoparticles (metallic, graphene, nanotubes, and conducting polymers) inside the gels. Additionally, true semi-interpenetrated networks of polyaniline (PANI) inside PNIPAM gels can be prepared by swelling the gel in true solutions of PANI in NMP. PNIPAM-based nanocomposites show a lower critical solution temperature (LCST) transition of the gel matrix, which can be reached by thermal heating or absorption of electromagnetic radiation (light, microwaves, radiofrequency) in the conductive nanomaterials. The characteristic properties (swelling degree and rate, LCST, solute partition, mass transport, hydrophilicity, biocompatibility) can be tuned by changing the functional groups in the copolymers and/or the other components in the nanocomposite. Mass transport and mechanical properties can be adjusted by forming materials with macro- (nanoporous and macroporous), micro- (microgels, thin films, Pickering emulsions), or nano- (nanogels, stabilized nanoparticles) sized features. The material properties are used to produce technological applications: sensors, actuators, controlled release, biological cell scaffolds and surfaces, antimicrobial, carriers of bioactive substances, and matrixes to immobilize enzymes and yeast cells.

A novel perylenediimide molecule: Synthesis, structural property relationship and nanoarchitectonics

A novel perylene diimide derivative (1) was synthesized by Stille coupling protocol to examine the effect of bulky group attached at bay position on the formation of nano-architectonics of PDI derivatives. The compound 1 was self-assembled by fast injection of chloroform solution in methanol to give nano-architecture. The size, shape and morphology of nano-architectonics were elucidated by combination of different experimental techniques such as UV–Vis spectrophotometer, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The construction of highly ordered nano and microstructures are operated by the property of π-conjugated dye molecules in more polar organic solvents due to π-π interaction between the perylene cores. From the UV–vis data, it is clear that the dye molecule shows solvatochromic behavior in low polar organic solvents and self-assembled behavior in methanol. The effect of bulky group at bay position and alkyl chain on imide position was investigated using UV–Vis absorption, differential scanning calorimetry (DSC), thermogravometric analysis (TGA), cyclic voltammetry (CV) and XRD. SEM and TEM images reveal the nano-architectonics morphology having diameter ≈400 ​nm. The d spacing values of XRD pattern has conformed π-π interactions. The effect of triphenylamine substituents on the π-π interaction between perylene molecules, the morphology of nano-architectonics and absorption properties of compound 1 are investigated by DFT calculations. On the basis of molecular orbitals, we have explained the electronic transitions and energy state in compound 1. The conjugation in compound 1 is affected by the degree of twisting in perylene ring due to the substituent at the bay positions of the perylene core.

Robust and impermeable metal shell microcapsules for one-component self-healing coatings

Metal shell microcapsules containing liquid 4,4′-bis-methylene cyclohexane diisocyanate (HMDI) were successfully synthesized by plating chemically a layer of Ni-P alloy on microcapsules surfaces. The metal shell occupied around 66.0 wt% of final microcapsules, providing great potential to improve microcapsules robustness. Final microcapsules with diameters of 184.3 ± 41.7 µm had a core fraction of 22.4 ± 0.6 wt%. The final microcapsule shells with a total thickness of 7.4 ± 0.4 µm was a three-layered structure, which comprised of an outer-layered Ni-P shell with a thickness of 5.5 ± 0.2 µm, a medium-layered PUF shell with a thickness of 369.0 ± 21.0 nm, and an inner-layered polyurea shell with a thickness of 1.7 ± 0.2 µm. More interestingly, final microcapsules remained stable core fraction and morphologies in most regular solvents including low polar organic solvents, high polar organic solvents, and water. The shell strength of final microcapsules was 28.5 ± 10.3 MPa, comparing with 6.6 ± 2.5 MPa of polymer shells. Moreover, the modulus of epoxy composites was stable relatively with microcapsules concentrations. Scratched self-healing epoxy coatings showed satisfactory anticorrosion performance in salty water (1 M).

Towards Naked Zinc(II) in the Condensed Phase: A Highly Lewis Acidic ZnII Dication Stabilized by Weakly Coordinating Carborate Anions.

The employment of the hexyl-substituted anion [HexCB11 Cl11 ]- allowed the synthesis of a ZnII species, Zn[HexCB11 Cl11 ]2 , 3, in which the Zn2+ cation is only weakly coordinated to two carborate counterions and that is soluble in low polarity organic solvents such as bromobenzene. DOSY NMR studies show the facile displacement of at least one of the counterions, and this near nakedness of the cation results in high catalytic activity in the hydrosilylation of 1-hexene and 1-methyl-1cyclohexene. Fluoride ion affinity (FIA) calculations reveal a solution Lewis acidity of 3 (FIA=262.1 kJ mol-1 ) that is higher than that of the landmark Lewis acid B(C6 F5 )3 (FIA=220.5 kJ mol-1 ). This high Lewis acidity leads to a high activity in catalytic CO2 and Ph2 CO reduction by Et3 SiH and hydrogenation of 1,1-diphenylethylene using 1,4-cyclohexadiene as the hydrogen source. Compound 3 was characterized by multinuclear NMR spectroscopy, mass spectrometry, single crystal X-ray diffraction, and DFT studies.

Towards Naked Zinc(II) in the Condensed Phase: A Highly Lewis Acidic ZnII Dication Stabilized by Weakly Coordinating Carborate Anions

AbstractThe employment of the hexyl‐substituted anion [HexCB11Cl11]− allowed the synthesis of a ZnII species, Zn[HexCB11Cl11]2, 3, in which the Zn2+ cation is only weakly coordinated to two carborate counterions and that is soluble in low polarity organic solvents such as bromobenzene. DOSY NMR studies show the facile displacement of at least one of the counterions, and this near nakedness of the cation results in high catalytic activity in the hydrosilylation of 1‐hexene and 1‐methyl‐1cyclohexene. Fluoride ion affinity (FIA) calculations reveal a solution Lewis acidity of 3 (FIA=262.1 kJ mol−1) that is higher than that of the landmark Lewis acid B(C6F5)3 (FIA=220.5 kJ mol−1). This high Lewis acidity leads to a high activity in catalytic CO2 and Ph2CO reduction by Et3SiH and hydrogenation of 1,1‐diphenylethylene using 1,4‐cyclohexadiene as the hydrogen source. Compound 3 was characterized by multinuclear NMR spectroscopy, mass spectrometry, single crystal X‐ray diffraction, and DFT studies.

Development of trace analysis for alkyl methanesulfonates in the delgocitinib drug substance using GC-FID and liquid–liquid extraction with ionic liquid

AbstractAlkyl methanesulfonates are genotoxic impurities that should be limited to an intake of not more than 1.5 µg/day, as regulated by the International Council for Harmonization guideline M7. We herein report a trace analysis of methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS), and isopropyl methanesulfonate (IPMS) in the delgocitinib drug substance using liquid–liquid extraction, with an ionic liquid as the sample-solving medium, and direct injection gas chromatography detected with a flame-ionization detector. The proposed method takes advantage of the fine solubility of ionic liquids toward the drug substance, the good extraction efficiency of alkyl methanesulfonates in liquid–liquid extraction using the Chem Elut cartridge with low-polar organic solvents, and the ability of alkyl methanesulfonates to concentrate in minimum amounts of organic solvent, resulting in excellent sensitivity and selectivity. Specifically, for the preparation of the sample solution, a mixture of 1-butyl-3-methylimidazolium chloride, water, and acetonitrile was used as the sample-solving media, extracted with diethyl ether, and the eluent was concentrated to 1 mL. The method showed good linearity, accuracy, and precision from 1 to 5 ppm, and the limits of detection of MMS, EMS, and IPMS were 0.1, 0.05, and 0.05 ppm, respectively.

Amphoteric Homotropic Allosteric Association between a Hexakis-Urea Receptor and Dihydrogen Phosphate.

Conformationally flexible hexakis-urea 1 was synthesized efficiently by condensing hexakis(aminomethyl)benzene with 4-nitrophenyl-(3,5-di-tert-butylphenyl)carbamate. The hexakis-urea 1 is unexpectedly soluble in organic solvents of low polarity due to intramolecular hydrogen bonding. The hexakis-urea 1 recognizes chloride, bromide, and acetate in a 1:2 host-guest ratio and in a positive allosteric manner in CDCl3 . The ability of 1 to recognize dihydrogen phosphate is a unique outcome, and the structure of the associated complex, which contains four dihydrogen phosphate ions, was clarified by single-crystal X-ray structural analysis. However, in solution, a complex with three dihydrogen phosphate ions was identified. The dihydrogen phosphate association in CDCl3 proceeds in an amphoteric allosteric manner; in a positive allosteric manner (K1 <K2 ) in the first step and a negative allosteric manner (K2 >K3 ) in the subsequent step.

N-doped carbon dots with tunable emission for multifaceted application: solvatochromism, moisture sensing, pH sensing, and solid state multicolor lighting

Novel N-doped green-emitting carbon dots (N-GCDs) that were responsive to various external stimuli and had high quantum yields (QYs) for multifaceted applications were synthesized from β-resorcylic acid and ethylenediamine using a hydrothermal process followed by a reflux method. The QYs of the N-GCDs were in the range of 17.36%–48.4% and were associated with different photoluminescent color emission in different solvents. Interestingly, the as-synthesized N-GCDs exhibited strict solvent polarity-dependent switchability (solvatochromism) and multicolor excitation-wavelength-independent emission in different solvents. Sensing of an analyte based on the switching of the photoluminescence (PL) emission maxima (λmax) is always preferred over that based on fluorescence quenching to avoid complexity and confusion regarding the initial fluorescence intensity (I0) and thus make the sensing process simple, rapid, ordered, and reliable. The N-GCDs exhibited blue emission in low-polarity organic solvents, but with the increase of the trace water content in the system, the PL emission peak gradually shifted to a higher wavelength (bathochromic shift) at a single-wavelength excitation. Thus, the N-GCDs are sensitive visual probes for the fluorescence detection of the trace water content in organic solvents without sophisticated processes. They also indicate the pH-response behavior. When the pH decreased from 7.6 to 2.4, the fluorescence emission intensity decreased, with a particularly good linear relationship (R2 = 0.990) in the range of 3.8–6.2. Moreover, the polarity-dependent-emission property was observed in the solid state polymer matrices. Multicolor-emissive N-GCD/polymer films were prepared by integrating N-GCDs with the polymer matrices of different polarity, demonstrating the application of carbon dots for solid-state lighting.

Synthesis of pyramidal tetraarylborate pentads

Tetrahedral tetraarylborate pentads were synthesized by a typical click reaction, copper-catalyzed azide–alkyne cyclization, which exhibited interesting ionic dissociation in low polar organic solvents.

Synthesis and Conductivity Studies of Tetraarylphosphonium Salts As Potential Electrolytes in Advanced Batteries

The purpose of this study was to synthesize polysubstituted tetraarylphosphonium/tetrakis (pentafluorophenyl) borate salts 3, also known as TAPR/TFAB where R is a substituent, and to measure their conductance/conductivity in low-polarity media such as tetrahydrofuran (THF) and dichloromethane (DCM). Such determination was to provide a rationale to the question of whether these compounds, and other weakly coordinating cations/anions combinations are suitable electrolytes for advanced batteries which are energized in safer, low-polarity organic solvents.

Boronic Acids as Phase-Transfer Reagents for Fischer Glycosidations in Low-Polarity Solvents

Protocols employing phenylboronic acid as a phase-transfer reagent for Fischer glycosidations in low-polarity organic solvents are described. In addition to providing rate acceleration, the formation of a substrate-derived boronic ester alters the course of the reaction by selective promotion of a furanoside- or pyranoside-selective pathway. Computational modeling of the relative energies of the glycoside-derived boronic esters provides results that are qualitatively consistent with the observed distributions of furanoside versus pyranoside products. The boronic esters that are obtained as direct products of these reactions serve as protected intermediates for the synthesis of functionalized glycosides. Complexation of particular diol groups by the boronic acid also enables selective transformations of mixtures of carbohydrates.

Towards a frustrated Lewis pair-ionic liquid system

An ionic liquid encompassing a bulky tertiary amine was synthesized and used as a dual solvent-reactant for the formation of a frustrated Lewis pair with tris(pentafluorophenyl)borane, forming a pseudo-frustrated Lewis pair-ionic liquid system. The ionic liquid-LA system is prone to self-ionization, i.e. with the formation of iminium and boron hydride species, which are able to form adducts with CO2. Compared to frustrated Lewis pairs operating in organic solvents of low polarity, more forcing conditions are required for the ionic liquid system. Calculations indicate that the anion of the ionic liquid interacts with the Lewis acidic boron center, hindering reactivity, and rationalizing the low reactivity observed.

Catalytic hydrolysis of starch for biohydrogen production by using a newly identified amylase from a marine bacterium Catenovulum sp. X3

An identified cold-adaptive, organic solvents-tolerant alkaline α-amylase (HP664) from Catenovulum sp. strain X3 was heterologously expressed and characterized in E. coli, and it was further applied to starch saccharification for biohydrogen production. The recombinant HP664 belongs to a member of glycoside hydrolase family 13 (GH13), with a molecular weight of 69.6kDa without signal peptides, and also shares a relatively low similarity (49%) to other reported amylases. Biochemical characterization demonstrated that the maximal enzymatic activity of HP664 was observed at 35°C and pH 9.0. Most metal ions inhibited its activity; however, low polar organic solvents (e.g., benzene and n-hexane) could enhance the activity by 35–50%. Additionally, HP664 also exhibited the catalytic capability on various polysaccharides, including potato starch, amylopectin, dextrin and agar. In order to increase the bioavailability of starch for H2 production, HP664 was utilized to elevate fermentable oligosaccharide level, and the results revealed that the maximal hydrolytic percentage of starch was up to 44% with 12h of hydrolysis using 5.63U of HP664. Biohydrogen fermentation of the starch hydrolysate by Clostridium sp. strain G1 yielded 297.7mL of H2 after 84h of fermentation, which is 3.73-fold higher than the control without enzymatic treatment of HP664.

Influence of Delipidation on Hg Analyses in Biological Tissues: A Case Study for an Antarctic Ecosystem

The use of low-polarity organic solvents is widespread in cleanup/extraction processes in order to carry compounds of interest, remove interferences and separate phases, among other uses. A large number of studies have used delipidation to remove excess of lipids to analyse carbon stable isotopes in biological tissues for trophic and behavioural ecology investigations. In this context, the primary aim of this study is to assess the influence of one delipidation process on the results of total mercury (Hg) analyses and the possible use of delipidated samples from previous analyses, such as for stable isotopes, in Hg level determination. Samples of vegetation (angiosperm, lichens and mosses), invertebrates (krill and limpets), fish (marbled and black rockcod), bird liver and eggs (Antarctic, Gentoo and Adelie penguins, kelp gull, Antarctic tern, cape petrel and giant southern petrel) and pinniped tissues (Weddell seal, crabeater seal, southern elephant seal and Antarctic fur seal) were analysed for Hg before and after delipidation by cyclohexane. The difference between the two measurements ranged individually from −63 to 136% (in the moss Sanionia uncinata) and the averages ranged from −60 to 66% (in pinniped tissues). The proportion of organic Hg, which presents considerable lipophilicity, but also high affinity for sulfhydryl groups in proteins, might be responsible for such variability. Given the limitations of our study, we think it is safe to say that delipidated samples could not be used to infer total Hg values in non-delipidated ones.

Synthesis of ionic liquid based on polysiloxane with quaternized imidazolium moiety

Polysiloxane derivatives having quaternized imidazolium moieties with different length of alkyl chains ([HPImn]Cl) (n is the number of methylene group) were prepared via quaternization reaction of poly(3-chloropropylmethylsiloxane) (P1) with 1-alkylimidazole derivatives (Imns). [HPImn]Cls were obtained with high quaternization ratio from 95 to 100 mol%. The glass transition temperatures (Tgs) of a series of [HPImn]Cls were lowered with increase in the length of alkyl chain in the case of the number of methylene group from 1 to 6; however, those were a little raised when the number of methylene group was 7 and 8 plausibly owing to the effects of the van der Waals interactions among long alkyl chains. [HPImn]Cls were dissolved in high polar solvents such as methanol, dimethyl sulfoxide, N,N-dimethylformamide and water. Also, the increase in the length of alkyl chains in [HPImn]Cls improved the solubility in low polar organic solvents such as chloroform and dichloromethane.

A lipase with broad solvent stability from Burkholderia cepacia RQ3: isolation, characteristics and application for chiral resolution of 1-phenylethanol.

Using both polar and low polar organic solvents (DMSO and toluene) as screening stress, a solvent-stable bacterium Burkholderia cepacia RQ3 was newly isolated. An organic solvent-stable lipase from strain RQ3 was purified in a single step with 50.1% recovery by hydrophobic chromatography. The purified lipase was homogenous on SDS-PAGE and had an apparent molecular mass of 33 kDa. The gene of lipase RQ3 with an open reading frame of 1095 bp encoding 364-amino acid residues was cloned. The optimal pH and temperature for lipase activity were 9.0 and 40 °C. The lipase was stable in a wide pH range of 6.0-10.0 and at temperature below 50 °C. Strikingly, all the tested hydrophilic and hydrophobic organic solvents significantly extended the half-life of lipase RQ3 compared with that in a solvent-free system, which indicated that lipase RQ3 showed a broad solvent tolerance to various organic solvents. The lipase demonstrated excellent enantioselective transesterification toward the (S)-1-phenylethanol with a theoretical conversion yield of 50% and ee p of 99.9%, which made it an exploitable biocatalyst for organic synthesis and pharmaceutical industries.

Graphene Quantum Dots Prepared from Graphene Hydrogels Basing on Hydrothermal Method

Graphene quantum dots (GQDs) is one of the derivatives of graphene. Due to the unique spin, electronic and optical properties, GQDs has attracted much attention. Graphene is a famous 2D and zero-bandgap material, and its size can be controlled to be from several micrometers to 30 inches. In principle, the bandgap of graphene can be tuned by varying its size. GQDs, less than 20 nm, can be considered as ultra-small fragments of graphene. The bandgap of small GQDs widens due to the quantum confinement effect. GQDs become semiconductors, which makes GQDs suitable for various fields such as optoelectronic devices, sensors and bio-imaging. Herein, we report a novel method to prepare graphene quantum dots (GQDs) from graphene hydrogels. Various methods of synthesizing GQDs have been reported, such as hydrothermal synthesis, solvothermal, electrochemical methods, microwave technology and the bottom-up method. In our study, graphene hydrogels were prepared using a hydrothermal technique. By immersion of the hydrogels in low-polarity organic solvents, GQDs were released from the hydrogels. This method did not require additional treatments such as the centrifugation, filtration and dialysis in the general hydrothermal process. These GQDs have the strongest emission at ~347 nm.