Mixed Organic Solvents Research Articles

Rapid and ultra-sensitive trace water determination in organic solvents utilizing nitrobenzoxadiazole (NBD)-based fluorescent sensing system

The presence of minute quantities of water in organic solvents can affect the progress of many reactions and cause unnecessary losses and even safety accidents in the chemical industry, especially in the productions process of organic fine chemicals. Therefore, it is necessary to carry out high-performance strategies for trace water detections in commonly used organic solvents. In this work, a fluorescent sensing system based on competitive binding of protons has been developed, demonstrating remarkable responses by UV–vis absorption and fluorescence two-modes toward a trace amount of water in organic solvents including 1,4-dioxane (Diox), tetrahydrofuran (THF), acetonitrile (MeCN), acetone (ACE), dimethylsulfoxide (DMSO) and mixed organic solvents (THF: MeCN=1: 1). The key component of the sensing system is a newly designed fluorophore NBD-PMA, which can be deprotonated to form a dynamic non-luminescent adduct, namely NBD-PMA-F, by an organic fluoride salt tetrabutylammonium fluoride (TBAF). NBD-PMA-F can be reprotonated via using trace water, exhibiting fluorescence turn on of the system. The as-prepared sensing system shows superior sensitivity, low detection limits (v/v, 0.0007 %), quick response speed (≤1.2 s) and good reversibility. Moreover, naked-eye visual rapid detection has also been successfully realized at ambient temperature, which demonstrated their practical applications value for trace water determinations.

Facile Synthesis of Poly(methyl methacrylate) Silica Nanocomposite Monolith by In Situ Free Radical Polymerization of Methyl Methacrylate in the Presence of Functionalized Silica Nanoparticles.

Novel porous poly(methyl methacrylate) (PMMA) silica nanocomposites have been produced by utilization of polymerization-induced phase separation in a simple one-pot approach. A facile free radical polymerization of MMA in the presence of surface methacrylate-functionalized silica nanoparticles was carried out in ethanol-based solvents, successfully producing novel, morphologically designable porous nanocomposite monoliths. Differing from standard free radical polymerization in solution, a mixture of good and poor solvents (ethanol/N,N-dimethylformamide ratio) for the resulting polymer was used to trigger spinodal phase separation. The influence of monomer concentration, as well as solvent composition, on the morphology of the resulting porous polymers has been investigated. Porous monolith structures composed of connected particles and co-continuous morphologies were observed under a scanning electron microscope depending on the polymerization conditions. The resulting polymers were insoluble and showed swelling characteristics in some organic solvents that are capable of dissolving regular PMMA, indicating covalent bonds between the functionalized silica nanoparticles and the polymer chains. The presence of silica particles in the final polymer was proven via an ATR-IR analysis. The glass transition temperature of the present PMMA-silica nanocomposite was higher than that of the conventional PMMA. The porous polymer immersed in a mixed organic solvent showed coloration induced by the Christiansen effect.

REMOVAL OF PRESSURE SENSITIVE TAPES FROM VINTAGE SILVER GELATIN PRINTS USING SELECTED GEL-BASED SYSTEMS: AN EXPERIMENTAL STUDY

Historical photographs play a significant role as records, documenting the various stages of the history of Egypt and reflecting our identity and social, cultural, and religious values. Silver gelatin prints were the dominant positive printing processes in the 20th century. One of the most common forms of damage found among photographic collections is tears, which may result from improper handling and misuse, inappropriate storage, disasters, and other factors. In the past, tears were mended using pressure-sensitive tapes by amateurs and conservators. Over time, these tapes caused damage to the photographic surfaces since they oxidised, forming stains that are difficult and sometimes impossible to remove. Recently, many gel-based systems have been developed for use in the conservation of different cultural and historical materials, particularly paper artifacts. The aim of this research is to evaluate the efficacy of Klucel G and agar, as gel systems that are favoured by conservation specialists, in removing pressure-sensitive tapes from the surfaces of silver gelatin prints, as well as to study their effect on the photographs themselves. Organic solvents were added to the gel systems, and invaluable old photographs were used for this study. After treatment, samples were subjected to artificial ageing at a temperature of 80°C and 65% RH. Evaluation of the selected treatments was carried out through visual inspection, microscopic examination, colorimetric measurements, and attenuated total reflectance Fourier transform infrared spectroscopy. Results showed that both gel-based systems with mixed organic solvents gave great results compared to the conventional methods in terms of tape removal. However, colour change was detected in the case of agar gel-treated samples. Agarose gel may be a more proper option.

A novel Cu@Ag nano paste with low porosity for rapidly sintering in air condition

The emergence of Cu@Ag core-shell nanoparticles presents a promising solution to address issues such as copper oxidation, the high cost of silver, and electro-chemical migration in high-power electronic devices, showcasing their potential for practical applications. In this study, Cu@Ag nanoparticles were synthesized via a liquid-phase reduction method, resulting in an average size of 30 nm. A low-boiling-point mixed organic solvent was meticulously prepared following Raoult's law, enabling the creation of a nano paste utilizing Cu@Ag nanoparticles. This innovation facilitated the sintering of fully dense joints under ambient air conditions, effectively mitigating the oxidation issue caused by silver dewetting behavior in Cu@Ag core-shell nanoparticles. Subsequently, the shear strength and microstructure of the joints were comprehensively studied under various sintering temperatures and durations. Notably, the joint exhibited a shear strength of 17.3 MPa when sintered at 250 °C for 30 min, while achieving full density at a sintering temperature of 300 °C for 30 min. These findings underscore the capacity of Cu@Ag core-shell nano paste to enable the production of high-performance joints under air conditions, utilizing thoughtfully selected organic components.

Thermal cleavage of hydrogen bond-induced LCST-type phase separation of PHEMA and related poly(hydroxyalkyl (meth)acrylate)s in mixed organic solvents

The length of the alkyl groups in both the polymer side chain and 1-alcohol good solvents would dictate the critical molar ratio for LCST-type phase separation.

Swelling and delamination of inorganic homoionic montmorillonite clay in water-polar organic mixed solvents.

The smectite group of clay minerals (smectites) consists of negatively charged clay layers and interlayer exchangeable cations. They are spontaneously delaminated in water to form single clay layers when the interlayer cations are small alkaline cations such as Na+ or Li+. This phenomenon known as osmotic swelling has fundamental importance in constructing novel clay-based nanomaterials. However, osmotic swelling of smectites has not been systematically investigated in organic solvents although this phenomenon should be useful for developing novel clay-organic nanocomposites. We report herein that montmorillonite, a typical smectite, with monovalent and divalent inorganic interlayer cations shows osmotic swelling accompanied by delamination of clay layers in water-acetonitrile and water-2-propanol mixed solvents, although inorganic interlayer cations have been believed to be inappropriate for delamination of smectites in organic solvents. The delamination is confirmed by a combination of macroscopic sample appearances, XRD patterns, and SEM images. Montmorillonite with interlayer Na+ or Li+ ions shows osmotic swelling in pure water and the mixed solvents but not in pure organic solvents. Montmorillonite with alkaline earth dications in the interlayer spaces is swollen in water-organic mixed solvents but not in either pure water or organic solvents alone. Partial delamination in several systems can be clarified from SEM images even though the sample appearances and XRD patterns do not give firm evidence. Such non-uniform swelling behavior of montmorillonite is related to the disordered stacking of the aluminosilicate layers with different morphologies in the clay powders as observed by SEM.

Facile synthesis of lanthanum-doped SrTiO3 nanocubes mediated by cetyltrimethylammonium bromide and tert-butylamine under solvothermal condition and their tunable electrical properties

The electrical conductivity of low concentrations of lanthanum-doped SrTiO3 nanocube ceramics synthesized using the facile solvothermal method in mixed organic and inorganic solvents with cetyltrimethylammonium bromide (CTAB) as a capping agent and tert-butyl amine (TBA) as a mineralizer was investigated. X-ray diffraction patterns confirmed the formation of a high-purity perovskite phase, corresponding to the standard data and the pattern refinement results. The particles of the sample were nanocubes, whereas the La-doped SrTiO3 sample particles were more uniform in size and shape, as shown in TEM images. The FT-IR spectrum confirmed the vibration of the CH3-N+ groups from CTAB and TBA, indicating an electrostatic interaction between their functional groups and the particle surface. Substitution of La3+ ions at low concentrations increased electrical conductivity compared to the undoped SrTiO3 sample. Lanthanum donates excess electrons, thereby increasing the number of electron carriers, which causes a reduction in the band gap energy according to the UV-DRS spectrum analysis using the Tauc equation.

Aggregation-dependent room temperature phosphorescence based on different polymorphs of 1,2,3-triazole derivates

It is significant and challenging to control the molecular packing in the aggregated state during the molecular design stage. Herein, a series of C4, C5 and N2-trisubstituted triazole derivatives have been designed to explore the relationship between packing modes and room temperature phosphorescence (RTP) properties. By introducing different substituents, these derivatives reveal different RTP properties and inherent mechanisms. TRA-H and TRA-F both have distinct crystalline polymorphs cultured by the evaporation of different mixed organic solvents. The lifetime of their RTP emissions exhibit distinct results due to the different packing modes in the aggregation state. Through careful analysis of experimental results, coupled with theoretical calculations, it is found that efficient intermolecular interactions between the adjacent triazoles, combined with the long-range orderly packing mode in the aggregated state are conducive to the longer phosphorescence lifetime.

Effects of Microfluidic Shear on the Plasmid DNA Structure: Implications for Polymeric Gene Delivery Vectors.

Microfluidic manufacturing of advanced gene delivery vectors necessitates consideration of the effects of microfluidic shear forces on the structural integrity of plasmid DNA (pDNA). In this paper, we expose pDNA to variable shear forces in a two-phase, gas-liquid microfluidic reactor and apply gel electrophoresis to analyze the products of on-chip shear-induced degradation. The effects of shear rate, solvent environment, pDNA size, and copolymer complexation on shear-induced degradation are investigated. We find that small naked pDNA (pUC18, 2.7 kb) exhibits shear rate-dependent shear degradation in the microfluidic channels in a mixed organic solvent (dioxane/water/acetic acid; 90/10/<0.1 w/w/w), with the extents of both supercoil isoform relaxation and complete fragmentation increasing as the maximum shear rates increase from 4 × 105 to 2 × 106 s-1. However, over the same range of shear rates, the same pDNA sample shows no evidence of microfluidic shear-induced degradation in a pure aqueous environment. Quiescent control experiments in the same mixed organic solvent prove that a combination of solvent and shear forces is involved in the observed shear-induced degradation. Furthermore, we show that shear degradation effects in mixed organic solvents can be significantly attenuated by complexation of pDNA with the block copolymer polycaprolactone-block-poly(2-vinylpyridine) prior to exposure to microfluidic shear. Finally, we demonstrate that medium (pDSK519, 8.1 kb) and large (pRK290, 20 kb) naked pDNA are more sensitive to shear-induced microfluidic degradation in the mixed organic solvent environment than small pDNA, with both plasmids showing complete fragmentation even at the lowest shear rate, although we found no evidence of shear-induced damage in water for the largest investigated naked pDNA even at the highest flow rate. The resulting understanding of the interplay of the solvent and shear effects during microfluidic processing should inform microfluidic manufacturing routes to new gene therapy formulations.

Photoinduced organocatalytic lignin C–C bond cleavage in mixed binary solvents

Lignin presents a renewable alternative of fossil feedstock to produce value-added aromatic chemicals. Oxidative cleavage of C−C bonds in lignin is of great importance, but obtaining aromatic monomers in high selectivity under mild conditions is challenging. Herein, we report a novel strategy of photoinduced oxidative C–C cleavage of lignin β–O–4 derivatives using photoredox organocatalysts, among which Mes-10-phenyl-Acr+-BF4– exhibited high yields of aromatic aldehydes and phenyl formate. Besides, mixed binary organic solvents were demonstrated to promote bond cleavage and inhibit over-oxidation side reactions. The absorbance, excitation, and interaction with the lignin model of the photocatalyst in different solvents were investigated by UV-Vis, PL, and CV tests. Furthermore, through mechanism studies, a C-centered radical intermediate was captured, providing evidence for the direct Cα−Cβ bond cleavage mechanism during the reaction. This work presents a new photocatalytic strategy and provides deep insights into the bond cleavage mechanism for lignin valorization.

Effect of Paint Exposure Among Paint Workers and DNA Damage: A Scoping Review

Paint contains various complex chemical mixtures, such as aliphatic hydrocarbons, aromatic hydrocarbons (primarily toluene), ketones, and benzene as reported at previous studies. Toxicity from some chemicals can cause early DNA damage with various factors. A scoping review was conducted via literature review on relevant studies on the effect of paint exposure on paint workers and DNA damage. A systematic search was conducted in October 2021 via PubMed, Scopus, and Web of Science databases. The key terms used were paint, solvent-based paint, organic solvent, mixed organic solvent, occupational exposure and DNA damage, oxidative stress, genotoxicity on a painter, paint worker. From 561 articles, only 13 articles were finally selected based on the inclusion, exclusion criteria, and eligibility criteria. The literature showed that biomonitoring studies on painters were consistently reporting positive and significant DNA damage due to exposure to different types of compounds mixed in a paint. However, there were fewer studies on paint manufacturing factory workers compared to painters while paint manufacturing workers exposed various chemical everyday during the paint production which potentially susceptible to occupational toxicity. In conclusion, this review suggests that exposure to paints could induce early DNA damage among paint workers and further investigations on paint exposure among paint manufacturing factory workers and the DNA damage were needed in order to improve occupational health among paint workers in the future.

CONDUCTIVITY STUDY OF SODIUM BROMIDE AND SODIUM CHLORIDE SALTS IN BINARY MIXTURES OFAQUEOUS AND ORGANIC SOLVENTS

The effect of solvent composition on the conductivity behaviour of sodium bromide (NaBr) and sodium chloride (NaCl) salts in binary mixed aqueous and organic solvents was evaluated using conductivity measurement. The specific conductivities of the salts in methanol-water, ethylene glycol-water and ethylene glycol-methanol mixtures were determined at different solvent compositions (0, 0.1, 0.4, 0.7 and 1) and concentrations (0.01, 0.02, 0.03, 0.04 and 0.05 M) of the salts with JENWAY 4510 conductivity meter at room temperature. The results show that the conductivities of the solutions of both salts in the mixed solvent systems were higher at lower organic solvent compositions and gradually decreased with increasing composition of the solvents. It was also observed that conductivity decreased as the hydrocarbon character of the organic solvent increased in all the binary mixtures. These results have been discussed on the basis of free-ion and ion-pair interactions as well as other chemical and physical properties of the single component solvents.

Post treatment for precise size and shape control of monodisperse CsPbBr3 nanocrystals under ambient condition using ZnBr2

A mixed passivation strategy is deployed to produce monodisperse and pure CsPbBr3 nanocrystals under ambient condition via post treatment using ZnBr2 in mixed organic solvents. This room temperature synthesis route provides precise size and shape control, and colloidal nanocubes or nanospheres can be obtained depending on the choice of organic solvents. Any secondary phases’ nucleation was inhibited. The ZnBr2 can reduce the Br− vacancies at the surface termination layers, thus enhancing their properties. This approach can potentially offer a cheap and viable route for perovskite nanocrystals in optical and electrical devices.

Detection of Carbamazepine and Its Metabolites in Blood Samples by LC-MS/MS.

To establish a method for the detection of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The blood samples were treated with 1-butyl-3-methylimidazolium hexafluorophosphate as an extraction solvent. The samples were extracted by ultrasound-assisted extraction and separated by ZORBAX Eclipse Plus C18, 95Å column. The mobile phase A aqueous solution containing 0.1% formic acid and 10 mmol/L ammonium acetate, and mobile phase B mixed organic solvent containing acetonitrile/methanol (Vacetonitrile∶Vmethanol=2∶3) were used for gradient elution at the flow rate of 1.00 mL/min. An electrospray ion source in positive mode was used for detection in the multiple reaction monitoring. The linearities of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples were good within the corresponding range, with correlation coefficients (r) greater than 0.995 6. The limits of detection were 3.00, 0.40 and 1.30 ng/mL, respectively. The limit of quantitation were 8.00, 1.00 and 5.00 ng/mL, respectively. The extraction recoveries ranged from 76.00% to 106.44%. The relative standard deviations of the intra-day and inter-day precisions were less than 16%. Carbamazepine and its main metabolite 10,11-dihydro-10,11-epoxycarbamazepine were detected in blood samples of death cases with a mass concentration of 2.71 μg/mL and 252.14 ng/mL, respectively. This method has high sensitivity and good selectivity, which is suitable for the detection of carbamazepine and its metabolites in blood samples, and can be used for carbamazepine-related forensic identifications.

Novel preparation strategy of graphdiyne (CnH2n-2): One-pot conjugation and S-Scheme heterojunctions formed with MoP characterized with in situ XPS for efficiently photocatalytic hydrogen evolution

As a new two-dimensional (2D) carbon hybrid material, graphdiyne has attracted much attention for its good electrical conductivity, tunable electronic structure and special electron transfer enhancement properties. With its unique atomic arrangement and 2D network of sp and sp2 conjugated hybridization, graphdiyne has a natural advantage in building active catalytic sites. Meanwhile, its special charge distribution gives graphdiyne the ability to be an electron acceptor or donor. Due to its special properties, it has great potential in the field of hydrogen evolution for photocatalytic water decomposition. In this work, a novel strategy for the simple synthesis of graphdiyne (CnH2n-2) by CaC2, hexabromobenzene and mixed organic solvents was firstly prepared and effectively enhanced the photocatalytic hydrogen evolution by topological semimetals (MoP). Combined with experimental tools such as in situ XPS, EPR and DFT calculations, the possible formation of S-Scheme heterojunctions between graphdiyne and MoP is proposed as an important strategy for the application of graphdiyne in the field of photocatalytic hydrogen evolution.

Zwitterion-neutral form equilibria and binding selectivity of pyridineboronic acids.

A 11B NMR study of 3-pyridineboronic acid at variable pH in water and 50 vol% aqueous dioxane confirms that the tautomeric equilibrium of the acid is shifted to the zwitterionic form in water, but to the molecular form in the mixed organic solvent. Interactions of 3- and 4-pyridineboronic acids with sialic acid, fructose and several other diols were studied by potentiometric titrations in a wide range of pH in water and water-organic mixtures. In all reaction media the stability of boronate complexes increases upon an increase in pH for neutral low acidic diols such as fructose and glucose but has the opposite trend for highly acidic sialic and lactic acids occurring as anionic species. The selectivity of pyridineboronic acids to sialate anions in an acidic medium is interpreted quantitatively by combining the pH-profiles with Brønsted type correlations for binding constants. In addition, mathematical expressions allowing one to predict the optimum pKa value of a boronic acid for the strongest binding of a given diol (sialic acid or fructose) at a given pH are suggested. The shifts in the tautomeric equilibrium induced by changing the solvent polarity in aqueous-organic mixtures are manifested in the magnitude of relative shifts of pKa of pyridineboronic acids induced by diol complexation.

Organic solvent exposure for the chronic kidney disease: updated systematic review with meta-analysis.

Studies on the relationship between organic solvent exposure and chronic kidney disease (CKD) have presented inconsistent results. Definition of CKD has changed in 2012, and other cohort studies have been newly published. Therefore, this study aimed to newly confirm the relationship between organic solvent exposure and CKD through an updated meta-analysis including additional studies. This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The search was conducted on January 2, 2023 using Embase and MEDLINE databases. Case-control and cohort studies on the relationship between organic solvent exposure and CKD were included. Two authors independently reviewed full-text. Of 5,109 studies identified, a total of 19 studies (control studies: 14 and cohort studies: 5) were finally included in our meta-analysis. The pooled risk of CKD in the organic solvent exposed group was 2.44 (1.72-3.47). The risk of a low-level exposure group was 1.07 (0.77-1.49). The total risk of a high-level exposure group was 2.44 (1.19-5.00). The risk of glomerulonephritis was 2.69 (1.18-6.11). The risk was 1.46 (1.29-1.64) for worsening of renal function. The pooled risk was 2.41 (1.57-3.70) in case-control studies and 2.51 (1.34-4.70) in cohort studies. The risk of subgroup classified as 'good' by the Newcastle Ottawa scale score was 1.93 (1.43-2.61). This study confirmed that the risk of CKD was significantly increased in workers exposed to mixed organic solvents. Further research is needed to determine the exact mechanisms and thresholds. Surveillance for kidney damage in the group exposed to high levels of organic solvents should be conducted. PROSPERO Identifier: CRD42022306521.

A molecular sponge that exclusively adsorbs acetonitrile

A tetra-armed cyclen (L) with phenylethynylmethyl groups as side-arms forms L·CH3CN inclusion crystals from acetonitrile–organic mixed solvents with high selectivity.

Structure and dynamics of the hyaluronan oligosaccharides and their solvation shell in water: organic mixed solvents

Hyaluronan (HA) is a natural polysaccharide occurring ubiquitously in the connective tissues of vertebrates widely used in the cosmetic and pharmaceutic industries. In numerous applications HA oligosaccharides are being chemically modified using reactions incompatible with aqueous solutions, often carried out in water:organic mixed solvents. We carry out molecular-dynamics (MD) simulations of HA oligosaccharides in water:1,4-dioxane and water:tert-butanol mixtures of different compositions. HA molecule causes a separation of the solvent components in its surroundings, especially in tert-butanol containing solutions, constituting thus a solvation shell enriched by water. Furthermore, interactions with ions are stronger than in pure water and depend on the solvent composition. Consequently, the dynamics of the HA chain varies with the solvent composition and causes observable conformational changes of the HA oligosaccharide. Composition of mixed solvents thus enables us to modify the interaction of HA with other molecules as well as its reactivity.

Physico-chemical properties of the association of cetyltrimethylammonium bromide and bovine serum albumin mixture in aqueous-organic mixed solvents

Herein, we have investigated the association behavior of bovine serum albumin (BSA) and cetyltrimethylammonium bromide (CTAB) using the conductivity method in H2O and H2O + organic mixed solvents at different temperatures. The association phenomenon was detected from the deviation of the conductivity changes with enhancing the surfactant concentration and changes of numerous physico-chemical properties, such as CMC, α, β and thermodynamic variables (∆G0m, ∆H0m and ∆S0m). The values of CMC for the CTAB + BSA system in 10 % (v/v) solvents follow the trend: CMCwater < CMCwater+DMSO < CMCwater+AN < CMCwater+DX < CMCwater+DMF. The interaction of BSA with CTAB is notably influenced due to a change of temperature and extent of hydration of BSA and surfactant. The obtained values of –∆G0m manifest that the association of BSA and CTAB mixture is a spontaneous process, while the values of –∆G0m in presence of 10 % (v/v) aq. organic solvents come out in the given sequence: -∆Gmo (H2O + DMSO) > ∆Gmo (H2O + DMF) > -∆Gmo (H2O + DX) > -∆Gmo (H2O + AN). The H-bonding, ion-dipole, along with the hydrophobic interactions, are believed to be the binding interactions between BSA and CTAB in the study media.