Acetonitrile Research Articles

High-performance supercapacitor electrode at commercial-level mass loading from N-enriched activated carbon derived from soybean dregs

N-enriched activated carbons (ACs) are prepared via a facile triple-doping technique route. The self-doping from the precursor of soybean dregs and additional introduction from egg white guarantee a high-level of N contents in the Hydrothermal carbonization (HTC) products (biochar). With a KOH-activation, relatively high surface area and easy-accessible ion channels are constructed. A post-doping from the subsequent ammonia-activation compensates the loss of the N contents during the KOH-activation. Relatively high surface area of 1518 m2/g and N atomic fraction of 4.311 % are achieved. Taking advantage of the compaction density of 0.68 g/cm3, electrodes with commercial-level mass loading of ∼10 mg/cm2 are fabricated with a moderate thickness of ∼0.15 mm. With symmetric supercapacitors (SCs) of commercial-level electrodes, high values are achieved of 357.1 F/g in gravimetric capacitance and 235.7 F/cm3 in volumetric capacitance at 0.5 A/g are achieved in 1 mol/L H2SO4. With 1 mol/L Et4NBF4 in acetonitrile (AN) as electrolyte, the gravimetric capacitance is 246.2 F/g and volumetric capacitance is 162.5 F/cm3. Moreover, a high energy density of 44.27 Wh/kg delivered at a high power of 2656 W/kg, good rate capability and excellent long-term cycling stability make the N-enriched ACs a competitive candidate for practical applications.

Investigating hydrophobic environment in alkyl-group-functionalized silica particle with various chain lengths using absorption microspectroscopy.

A well-known solvatochromic dye, Reichardt's dye (R-dye), was used to evaluate the hydrophobicity of alkyl-group-functionalized silica particles (ASPs) with different chain lengths. The absorption spectra of R-dye were measured in a single ASP in a mixed solution of water and an organic solvent (methanol (MeOH), ethanol (EtOH), acetonitrile (ACN), tetrahydrofuran (THF), or N,N-dimethylformamide (DMF)) using absorption microspectroscopy. The polarity parameter in the ASPs (ET), determined by the absorption maximum, was observed to be smaller than those in bulk solutions, indicating that R-dye was present in a more hydrophobic environment. In EtOH, THF, and DMF, R-dye was distributed within the alkyl chain layer including the organic solvent. An increase in the organic solvent content of the bulk solution led to a higher organic solvent concentration in the alkyl chain layer, resulting in a decrease in ET. In MeOH and ACN, the R-dye was distributed within the alkyl chain layer and concentrated phase. Moreover, with the increase in the organic molecule content, the distribution of R-dye in the concentrated phase became dominant in MeOH and ACN system, leading to an increase in the ET value. The findings presented in this paper are expected to attract the attention of a wide range of researchers in chromatography.

Solvent Engineering of Hole‐Transport Layer for Improved Efficiency and Stability in Perovskite Solar Cells

Although perovskite solar cells (PSCs) are one of the fastest‐growing photovoltaic technologies, many innovations are required to further improve performance and stability. The acetonitrile (ACN) solvent used to dissolve the Li‐TFSI salt in Spiro‐OMeTAD corrodes the perovskite thin film. In this study, 1‐methoxy‐2‐propanol (1MEO) and 2‐ethoxy‐ethanol (2ETO) solvents are used by replacing ACN. The utilization of 1MEO results in improved hole mobility in Spiro‐OMeTAD and reduction in defects at the perovskite/Spiro‐OMeTAD interface, thus diminishing nonradiative recombination. The recombination resistances in the low‐frequency range are determined via electrochemical impedance spectroscopy (EIS) and are found to be 3361.9 ohms for ACN‐Spiro‐OMeTAD, 4406.8 Ω for 1MEO‐Spiro‐OMeTAD, and 3815.3 Ω for 2MEO‐Spiro‐OMeTAD. These results indicate that the utilization of 1MEO and 2ETO instead of ACN effectively decreases charge recombination in PSCs. As a result, after replacing ACN with 1MEO and 2ETO, PSCs achieve a power conversion efficiency (PCE) of 21.3% and 20.0% respectively, while a PCE of 18.9% is obtained from the control device with ACN. During 45 d stability test, the initial efficiency of the control device decreases by 31.2%, while the 1MEO and 2ETO devices exhibit efficiency reductions of 12.2% and 7.7%, respectively.

An efficient RP-HPLC-PDA Method for Estimating Dolutegravir and Lamivudine in Combined Pharmaceutical Formulations using a Box-Behnken Design Approach

This study used a quality-by-design (QbD) method to build a novel, high-performance reverse-phase fluid chromatography (RP-HPLC) system with diode array detection (DAD) for the simultaneous measurement of dolutegravir (DLG) and lamivudine (LMV) tablets. In accordance with the International Council for Harmonization’s (ICH) requirements, chromatographic conditions were adjusted utilizing the Box-Behnken design (BBD), and the resultant technique was verified for linearity, system appropriateness, precision, accuracy, sensitivity, robustness, and stability of the solution. At retention durations of 2,271 and 3,431 minutes, LMV and DLG peaks were separated using a C-18 column with 150 x 4.6 mm and 5 μm particles. The mobile phase was 0.1% orthophosphoric acid (OPA): acetonitrile (ACN) (50:50, v/v) at a flow rate of 0.8 mL/min and a pH of 3 at 25°C. Peaks were seen at 254 nm and the volume of sample injection was 20L. The percent strength of the commercially available tablet is 98.89 and 98.76 for LMV and DLG, respectively, using a standard calibration curve. The developed RP-HPLC technique’s stability is shown by the suggested RP-HPLC method’s capacity to identify LMV and DLG in the existence of their degradation products. As per ICH requirements, the findings of the validation parameters for linearity, system appropriateness, accuracy, precision, robustness, and sensitivity were all within acceptable limits. It is simple to use, accurate, efficient, and reasonably priced to employ the innovative RP-HPLC technology with BBD application for QbD.

Revised gas-phase formation network of methyl cyanide: the origin of methyl cyanide and methanol abundance correlation in hot corinos

ABSTRACT Methyl cyanide (CH3CN) is one of the most abundant and widely spread interstellar complex organic molecules (iCOMs). Several studies found that, in hot corinos, methyl cyanide and methanol abundances are correlated suggesting a chemical link, often interpreted as a synthesis of them on the interstellar grain surfaces. In this article, we present a revised network of the reactions forming methyl cyanide in the gas phase. We carried out an exhaustive review of the gas-phase CH3CN formation routes, propose two new reactions, and performed new quantum mechanics calculations of several reactions. We found that 13 of the 15 reactions reported in the databases KIDA and UDfA have incorrect products and/or rate constants. The new corrected reaction network contains 10 reactions leading to methyl cyanide. We tested the relative importance of those reactions in forming CH3CN using our astrochemical model. We confirm that the radiative association of CH3+ and HCN, forming CH3CNH+, followed by the electron recombination of CH3CNH+, is the most important CH3CN formation route in both cold and warm environments, notwithstanding that we significantly corrected the rate constants and products of both reactions. The two newly proposed reactions play an important role in warm environments. Finally, we found a very good agreement between the CH3CN predicted abundances with those measured in cold (∼10 K) and warm (∼90 K) objects. Unexpectedly, we also found a chemical link between methanol and methyl cyanide via the CH$_{3}^{+}$ ion, which can explain the observed correlation between the CH3OH and CH3CN abundances measured in hot corinos.

Exploring the solubility and solvation energetics of L-phenylalanine across diverse aqueous organic solutions at five equidistant temperatures (288.15 K to 308.15 K)

This research elucidates comprehensive insights into the dissolution nature and solvation energetics of L-phenylalanine across distinct solvent environments. Specifically, the investigation encompasses saturated solubility measurements and the subsequent derivation of overall transfer free energies (ΔGt0(i)) and entropies (ΔSt0(i)) at 298.15 K, of L-phenylalanine from an aqueous medium to aqueous solutions comprising protic ethylene glycol (EG), dipolar aprotic N,N-dimethylformamide (DMF), acetonitrile (ACN), and dimethyl sulfoxide (DMSO). In this study the 'gravimetric method' was used to find the saturated solubilities of L-phenylalanine at five equidistant temperatures (288.15 K to 308.15 K). These experimental solubility measurements serve as the foundational dataset for the subsequent determination of transfer energies. The investigated drenched or equilibrium solubility data was applied to ascertain the solvation energies. In case of pure solvent, we get the solubility trend of L-phenylalanine as follows: ACN < DMSO < DMF < EG < water, at any temperature. At 298.15 K, we found the solubilities of L- phenylalanine in pure solvents like water, EG, DMF, DMSO and ACN are 0.1675, 0.0911, 0.0888, 0.0850 and 0.0811 mol·kg−1 respectively. A pivotal facet of this study involves the examination of the correlation between the saturated solubility of L-phenylalanine and the intricate characteristics of its solvation energetics across diverse aqueous organic solvent systems.

Validated HPLC-UV method for amphotericin B quantification in a critical patient receiving AmBisome and treated with extracorporeal replacement therapies.

Amphotericin B (AMB) is a polyene macrolide antifungal agent used for treating invasive fungal infections. Liposomal AMB is a lipid dosage form, available as AmBisome, which reduces the toxicity of the drug. A simple HPLC-UV method was developed for the determination of AMB in plasma to study its pharmacokinetic profile in a critical patient receiving AmBisome and treated with extracorporeal replacement therapies. Sample preparation was performed using plasma deproteinization and drug release from liposome by the addition of acetonitrile (ACN)/zinc sulfate and ultrasonication. Chromatographic separation was performed using a C18 column and a mobile phase consisting of phosphate buffer (pH 3.0)/ACN (65/35, v/v). The UV detector was set at 407 nm. The total run time analysis was 23 min. The method was validated according to the standard guidelines and applied to study the pharmacokinetics of AMB in a critical patient. The total run time analysis obtained was shorter than that of the previously reported methods, being useful for therapeutic drug monitoring or pharmacokinetic profile research.

Separation and quantification of Azvudine in plasma of patients with COVID-19 using LC-MS/MS

Azvudine (FNC) is a new drug conditionally approved in 2022 for the treatment of coronavirus disease 2019 (COVID-19) in China. However, the exposure level of FNC in COVID-19 patients in clinical practice is still obscure, and there is no liquid chromatography-tandem mass spectrometry (LC-MS/MS) or LC method reported for quantifying the FNC. In this study, a simple, fast, and reliable LC-MS/MS method using L-phenylalanine-D5 (Phe-D5) as the internal standard (IS) was developed for the quantification of FNC in plasma from COVID-19 patients. After simple protein precipitation with methanol, the analyte in the supernatant was separated on Waters Atlantis® T3 (2.1 ×100 mm, 3.0 µm) column with the mobile phase consisting of acetonitrile (ACN) - aqueous solution (containing 0.03% heptafluorobutyric acid and 0.2% formic acid). The mobile phase was delivered at 0.3 mL/min in an isocratic elution program (15:85, V: V). The linear relationship of FNC was good within the calibration range of 2.0 – 2000.0 ng/mL, with the recovery of FNC ranging from 81.37% to 103.31% and the matrix effect was 94.77%− 109.83%. The short-term, long-term, and freeze-thaw stability of the FNC assessed in method was acceptable, and all other items met the requirements of validation of the biological analytical method. Finally, the method was applied to detect the exposure level of FNC in plasma samples from patients diagnosed with COVID-19, and the results, which are within the linear range of the method, showed huge inter-individual variation, supporting the significance of therapeutic drug monitoring of FNC.

Looking for evidence of high-mass star formation at core scale in a massive molecular clump

Context. High-mass stars are formed as a result of the fragmentation of massive molecular clumps. However, what it is not clear is whether this fragmentation gives rise to stable prestellar cores massive enough to directly form high-mass stars or leads to prestellar cores of low masses that, by acquiring material from the environment, generate high-mass stars. Several recent observational studies focused on the characterisation of prestellar massive clump candidates. Nevertheless, studies of active massive clumps at different evolutionary stages are still needed to gain a complete understanding of how high-mass stars form. Aims. We present a comprehensive physical and chemical study of the fragmentation and star formation activity towards the massive clump AGAL G338.9188+0.5494, which harbours the extended green object EGO 338.92+0.55(b). The presence of an EGO embedded in a massive clump suggests that high-mass star formation is occurring at clump scale. The main goal of this work is to find evidence of such high-mass star formation, but at core scale. Methods. Using millimetre observations of continuum and molecular lines obtained from the Atacama Large Millimeter Array database at Bands 6 and 7, we study the substructure of the massive clump AGAL G338.9188+0.5494. The angular resolution of the data at Band 7 is about 0″.5, which allows us to resolve structures of about 0.01 pc (~2000 au) at the distance of 4.4 kpc. Results. The continuum emission at 340 GHz reveals that the molecular clump is fragmented into five cores, labelled C1 to C5. The 12CO J = 3−2 emission shows the presence of molecular outflows related to three of them. The molecular outflow related to core C1 is among the most massive (from 0.25 to 0.77 M⊙) and energetic (from 0.4 × 1046 to 1.2 × 1046 erg), considering studies carried out with similar observations towards this type of source. Rotational diagrams for the CH3CN and CH3CCH yield temperatures of about 340 and 72 K, respectively, for the core C1. The different temperatures show that the methyl cyanide would trace a gas layer closer to the protostar than the methyl acetylene, which would trace outermost layers. Using a range of temperatures going from 120 K (about the typical molecular desorption temperature in hot cores) to the temperature derived from CH3CN (about 340 K), the mass of core C1 ranges from 3 to 10 M⊙. The mid-IR 4.5 µm extended emission related to the EGO coincides in position and inclination with the discovered molecular outflow arising from core C1, which indicates that it should be the main source responsible for the 4.5 µm brightness. The average mass and energy of such a molecular outflow is about 0.5 M⊙ and 1046 erg, respectively, which suggest that 10 M⊙ is the most likely mass value for core C1. Additionally, we find that the region is chemically very rich with several complex molecular species. In particular, from an analysis of the CN emission, we find strong evidence that this radical is indirectly tracing the molecular outflows, or, more precisely, the border of the cavity walls carved out by such outflows, and therefore we point out that this is probably one of the first clear detection of CN as a tracer of molecular outflows in star-forming regions.

Densities and excess molar volumes of the binary systems of the ionic liquid trihexyl(tetradecyl)phosphonium bromide mixed with acetonitrile or tetrahydrofuran at temperatures from 293.15 to 313.15 K

Experimental densities and excess molar volumes of two binary mixtures composed of the ionic liquid trihexyl(tetradecyl)phosphonium bromide ([THTDP][Br]) mixed with acetonitrile (ACN) or tetrahydrofuran (THF) are reported in this work. Measurements were made using a vibrating tube densimeter at temperatures from 293.15 to 323.15 K. Both binary systems were studied in the whole composition range along with the pure compounds. Excess molar volumes were calculated from the experimental densities and were fitted with the Redlich–Kister polynomial equation. Excess molar volumes were negative for the mixtures and became more negative as the temperature increased. In addition, the ERAS model was applied for the modeling of excess molar volumes.

(Invited) Highly Stable, Crosslinked Polymer Membranes for Non-Aqueous Flow Batteries

Long-term energy storage is a crucial stepping stone for the introduction of renewable sources in the energy mix due to their intermittent nature. Non-aqueous Flow Batteries (NFBs) are expected to operate at higher potential differences in comparison to conventional aqueous systems, thus yielding an improved power density. However, among the several issues of NFBs, it is pivotal to develop ion-conducting separators stable in organic solvents.Here we present a new family of ionomers which proved promising as candidates to implement this crucial function. The ionomers are founded on the strong ionic interactions between the functionalities of a polyamide-based material (P) and a perfluorosulfonic acid macromolecule (N). The latter interactions establish crosslinks between the two starting macromolecules. Consequently, the polymeric structure of the final ionomer is reorganized, improving the mechanical properties and curtailing the swelling upon immersion in organic solvents.The membranes obtained from two of the proposed ionomers, labelled “P-N0.77” and “P-N0.89”, show a swelling < 7% after 1000 hours of immersion both in acetonitrile (ACN) and in a 1:1 vol./vol. mixture of ethylene carbonate and propylene carbonate (EC:PC). Upon exchanging the membranes with tetraethylammonium (TEA+) cations, a common benchmark mobile specie for NFBs, it is shown that: (i) P-N0.77 exhibits a conductivity of 0.4∙10-3 S∙cm-1 and 0.9∙10-3 S∙cm-1 at 25°C in 0.1 M TEA+ in ACN and 0.1 M TEA+ in EC:PC, respectively; and (ii) P-N0.89 shows a conductivity of 1.5∙10-3 S∙cm-1 and 0.5∙10-3 S∙cm-1 in the same conditions.These results suggest that the proposed materials are suitable for application in NFBs, opening the door to the long-term operation of these devices.

(Invited) 2D Mxenes for Energy Storage Applications

MXenes are a family of two-dimensional (2D) transition metal carbides and nitrides, with a general structure of Mn+1XnT x , where M is the transition metal, X is carbon and/or nitrogen, and T represents the surface terminations (F, O, OH). MXenes have attracted attention in a multitude of energy storage applications due to their high electronic conductivity, tunable interlayer spacing, redox-active transition metals, and hydrophilic surface groups. In this talk, we discuss the use of MXene electrodes in supercapacitor applications, including aqueous, non-aqueous, and water-in-salt electrolytes. The variability of MXenes is demonstrated with each electrolyte system showing unique electrochemical responses, not limited to redox and/or intercalation pseudocapacitance, and hydrated cation intercalation. Furthermore, the versatility of the hydrophilic, 2D morphology of MXenes is demonstrated through its use in multiple form factors, not limited to flexible free-standing films, multilayer powder electrodes, interdigitated microsupercapacitors, knitted textiles, and more. New directions and perspectives for MXenes in energy storage are discussed, including MXenes’ use as passive components (separators, current collectors, binders, scaffolds, conductive additives) in energy storage systems. Figure 1 (A) Schematic illustration showing MXenes’ electrochemical properties for ion storage applications. (B) Cyclic voltammetry (CV) data collected at scan rates from 10 to 100,000 mV·s−1 for a 90-nm-thick Ti3C2T x film. (C) Influence of an electrolyte’s solvent on the lithium-ion storage capacity of Ti3C2T x ; CV curves of microporous Ti3C2T x electrode in 1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in DMSO, acetonitrile (ACN), or propylene carbonate (PC) electrolytes. (D) A digital photograph showing the wafer scale fabrication of an array of 143 MXene microsupercapacitors. (E) Photograph of a knitted textile with an interdigitated pattern made using Ti3C2T x MXene-coated cotton yarn to produce electrodes for wearable textile supercapacitor.Reference[1] A. VahidMohammadi, J. Rosen, Y. Gogotsi, Science, 2021, 372, eabf1581. Figure 1

Process design and multi-objective optimization for separation of different feed composition of acetonitrile / ethanol / water with extractive distillation by varying pressure / pervaporation

In order to separate and purify the reaction raw material ethanol (EtOH) and product acetonitrile (ACN) from the azeotrope of ACN / EtOH / water, an efficient extractive distillation by varying pressure process (EDP) was designed to separate them. Because the feed composition in industrial production was constantly changing, processes of different feed compositions was simulated. Taking into account both economic and environmental factors, the non-dominated sorting genetic algorithm comprehensively optimizes the parameters. The azeotrope was pressure sensitive and the pressure parameter was also optimized in order to improve the efficiency of process energy utilization. Heat exchange network optimization technology was used to fully utilize excess heat in the process. The distillation coupled pervaporation technology has also been designed to explore emerging technologies. Among the three different coupling processes, the performance of EDP-pervaporation (EDPV) was better. Compared with EDP, EDPV under different schemes reduce the total annual cost (TAC) and gas emissions by more than 15% and 21 %, respectively. It was found that the energy consumption was related to the normal distance from the feed composition to the distillation boundary and isovolatility curve.

Diphenylsulfoxide exhibits an outstanding solubility in Methanol: Physicochemical and quantum chemical evidences. Comparison to acetonitrile

Diphenylsulfoxide (Ph2SO) represents a noteworthy organic substance composed of bulky amphiphilic molecules. The chemical interest in Ph2SO arises from a peculiar combination of the strongly polar and strongly nonpolar moieties which are uniquely packed. The solubility of Ph2SO in conventional organic solvents is a cornerstone of its prospective applications. In the present work, the full concentration ranges of the possible homogeneous solutions of diphenylsulfoxide (Ph2SO) in acetonitrile (ACN) and methanol (MEOH) have been investigated by densitometry, UV–vis, FTIR spectroscopy, and quantum-chemical calculations. For the first time, we unraveled an outstanding solubility of Ph2SO in MEOH. The homogeneous solutions form up to the molality of 0.9 mol kg−1. This observation is unexpected from the conventional chemical wisdom because Ph2SO contains twenty-two non-polar interaction sites vs. two polar interaction sites. Based on the volumetric measurements, we revealed that the partial molar volumes of Ph2SO depend somewhat on solvent (MEOH, ACN) peculiarities. The effects of solvent on the spectral characteristics of diphenylsulfoxide have been considered. The numerical simulations based on the systematic potential landscape exploration corroborate the existence of several types of supramolecular species involving Ph2SO and solvent molecules simultaneously. The peculiar anisotropic Ph2SO-MEOH coupling, which is a strong hydrogen bonding, along with the small size of the solvent molecules is responsible for the recorded outstanding solubility in the methanol media. In turn, the performance of ACN is somewhat less encouraging notwithstanding the way higher dipole moment of its molecules. As an amphiphilic solute, Ph2SO may boost the solubilities of hydrophobic solutes by interfacing its coupling with polar media. The reported results inspire further explorations of Ph2SO to design task-specific liquid systems.

Tetramethylalloxazines as efficient singlet oxygen photosensitizers and potential redox-sensitive agents

Tetramethylalloxazines (TMeAll) have been found to have a high quantum yield of singlet oxygen generation when used as photosensitizers. Their electronic structure and transition energies (S0 → Si, S0 → Ti, T1 → Ti) were calculated using DFT and TD-DFT methods and compared to experimental absorption spectra. Generally, TMeAll display an energy diagram similar to other derivatives belonging to the alloxazine class of compounds, namely π,π* transitions are accompanied by closely located n,π* transitions. Photophysical data such as quantum yields of fluorescence, fluorescence lifetimes, and nonradiative rate constants were also studied in methanol (MeOH), acetonitrile (ACN), and 1,2-dichloroethane (DCE). The transient absorption spectra were also analyzed. To assess cytotoxicity of new compounds, a hemolytic assay was performed using human red blood cells (RBC) in vitro. Subsequently, fluorescence lifetime imaging experiments (FLIM) were performed on RBC under physiological and oxidative stress conditions alone or in the presence of TMeAll allowing for pinpointing changes caused by those compounds on the intracellular environment of these cells.

Synthesis and characterization of mehtylammonium bismuth iodide via solvent engineering

Hybrid organic–inorganic halide perovskites (OIHPs) are an emerging class of photovoltaic materials that have gained tremendous attention in the field of optoelectronics. This work aims to investigate the characteristics of bismuth-based halide perovskite via solvent engineering for solar cell application. A bismuth-based organo-inorganic perovskite was synthesized and characterized for solar cell application via solvent engineering using Gamma Butyrolactone (GBL) as the based solvent and enhanced with Methylamine (MA) and acetonitrile (ACN). A solution processing facile method was adopted in the synthesis of the perovskite. The solvent engineering aims to tune its band gap and a remarkable band gap of 1.58eV which is within the range of an ideal band gap (1.5-1.6) required for solar cell application. The XRD micrograph exhibited several narrow sharp peaks which indicated crystallinity formation of the synthesized sample with 86% crystallinity. The FESEM/EDS micrograph indicated nature of the formed crystals and the chemical composition of the sample. A multilayer heptagonal crystal was observed. The TGA result showed that the sample is thermally stable at a temperature of 200oC before degradation occurred.

Synthesis and electrochemical properties of sulfur-nitrogen-doped multi-walled carbon nanotubes

Multi-walled carbon nanotubes doped with sulfur and nitrogen (S-N-MWCNTs) were grown onto silicon/silicon oxide wafer by means of chemical vapor deposition upon decomposition of dimethyl sulfoxide (DMSO) and acetonitrile (ACN) in presence of catalyst. The S-N-MWCNTs were characterized by scanning electron microscopy combined with energy dispersive X-ray spectroscopy. The findings demonstrate that S-N-MWCNTs exhibit bamboo-shaped nanostructure, quite similar to pure nitrogen-doped carbon nanotubes. The S-N-MWCNTs were investigated with respect to their electrochemical response to ferrocyanide/ferricyanide, [Fe(CN)6]4-/3- in potassium chloride aqueous solutions by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The recorded CVs demonstrate strong dependence of electrochemical response, electron transfer kinetics, and sensitivity of S-N-MWCNTs on concentration of decomposed DMSO precursor. Namely, upon increasing concentration of decayed DMSO up to 2% wt. the current density, the electron transfer kinetics, and the sensitivity of S-N-MWCNTs toward [Fe(CN)6]4-/3- tend to enhance. The extracted EIS results approve that when DMSO reaches the optimum concentration of 2% wt. the barrier for electron transfer decreases significantly leading, consequently, to faster electron transfer kinetics. The S-N-MWCNTs exhibit considerable stability and excellent reproducibility, and thus it can be considered suitable analytical tool for detection of redox systems at micromolar level.

Nitrogen-doped Ti3C2Tx/TiO2-graphene hybrid materials with 3D interconnected structure compatible with ionic liquid-based electrolyte for high performance supercapacitors

Ti3C2Tx, a typical MXene, bears tremendous attention as a type of potential electrode materials for supercapacitors. Regrettably, though Ti3C2Tx electrode has excellent capacitance in aqueous electrolytes, it cannot achieve high energy density due to a narrow operating potential window of the aqueous electrolytes. Herein, we demonstrate a well-designed hybrid material: nitrogen-doped Ti3C2Tx-reduced graphene oxide with in situ formed TiO2 nanopaticles bridged by -NH- (N-Ti3C2Tx/TiO2-RGO), and meanwhile formulate a ternary mixed electrolyte of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EmimTFSI), acetonitrile (ACN), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) to match the hybrid material. The N-Ti3C2Tx/TiO2-RGO hybrid possesses a 3D cross-linked porous structure with rapid transport channels for the electrolyte ions. The formulated ionic liquid-based electrolyte has a wide electrochemical stability window and free lithium ions are able to conduct Faradaic redox reactions. Benefiting from its unique architectural structure, the N-Ti3C2Tx/TiO2-RGO material delivers an enhanced specific capacitance (specific capacity) of 188 F g−1 (338 C g−1) at 1 A g−1 and exhibits a high rate capability. Furthermore, the assembled asymmetrical supercapacitor with the N-Ti3C2Tx/TiO2-RGO-5 anode and the self-synthesized p-phenylenediamine functionalized reduced graphene oxide (PPD-RGO) cathode delivers a high energy density of 46 Wh kg−1 at a high-power density of 1550 W kg−1. This work develops a simple strategy to assemble 2D MXene sheets into 3D porous electrode materials compatible to the ionic liquid-based electrolyte for high performance supercapacitors.

Solid-liquid phase equilibrium and thermodynamic properties analysis of Bazedoxifene acetate in fifteen kinds of mono-solvents

Crystallization is widely used for the isolation and purification of active pharmaceutical ingredients (APIs) in the final manufacturing stage. Bazedoxifene (BZD) acetate, classified as a third-generation selective estrogen receptor modulator, is employed in the treatment of postmenopausal osteoporosis. This work reports the equilibrium solubility data of BZD acetate in fifteen different mono-solvents, including methanol, ethanol, n-propanol, i-propanol, n-butanol, ethyl formate, methyl acetate, ethyl acetate, acetone, 2-butanone, cyclohexanone, tetrahydrofuran (THF), 2-methyltetrahydrofurane (2-MeTHF), 1,4-dioxane and acetonitrile (ACN), within the temperature range “T = 283.15–323.15 K” under p = 0.1 MPa. The solubilities of BZD acetate in various solvents increase with increasing temperature. Among the alcoholic solvents, the solubility order is as follows: methanol > ethanol > n-propanol > n-butanol > i-propanol. In esters solvent, the solubility of BZD acetate decreases in the following order: methyl acetate > ethyl acetate > ethyl formate. For ketones solvent, the solubility decreases in the following order: cyclohexanone > acetone > 2-butanone. The maximum value of BZD acetate solubility was 0.011 mol·mol−1 in tetrahydrofuran at T = 323.15 K, but the least data was found in ethyl formate at 283.15 K. Four thermodynamic models, i.e., the Yaws model, modified Apelblat model, λh model, and Wilson model were applied to fit the solubility data of BZD acetate in different solvents. Among them, the Wilson model represents the most accurate fitting outcomes. Finally, the thermodynamic functions of mixing (including enthalpy, entropy, and Gibbs energy) were calculated, and the results indicate a mixing process that is both spontaneous and driven by entropy. The solubility data, correlated models, and derived thermodynamic functions present essential thermodynamic fundamentals for the industrial production of BZD acetate crystallization, facilitating efficient separation and purification.

Detection and modelling of CH3NC in TMC-1

ABSTRACT Two closely related isomeric pairs of cyanides, CH3[CN/NC] and H2C[CN/NC], are studied in cold, dark interstellar cloud conditions. In contrast to the diverse detections of methyl cyanide (CH3CN) in space, methyl isocyanide (CH3NC) has previously only been observed in warm and hot star-forming regions. We report the detection of CH3NC in the cold pre-stellar core Taurus Molecular Cloud (TMC-1) using the Green Bank Telescope with a detection significance of 13.4σ. Hyperfine transitions in H2CCN and quadrupole interactions in CH3CN and CH3NC were matched to a spectral line survey from the Green Bank Telescope Observations of TMC-1: Hunting for Aromatic Molecules large project on the Green Bank Telescope, resulting in abundances with respect to hydrogen of $1.92^{+0.13}_{-0.07} \times 10^{-9}$ for the cyanomethyl radical (H2CCN), $5.02^{+3.08}_{-2.06} \times 10^{-10}$ for CH3CN, and $2.97^{+2.10}_{-1.37} \times 10^{-11}$ for CH3NC. Efforts to model these molecules with the three-phase gas-grain code nautilus in TMC-1 conditions overproduce both CH3CN and CH3NC, though the ratio of ∼5.9 per cent is consistent across observations and models of these species. This may point to missing destruction routes in the model. The models capture the larger abundance of H2CCN well. Dissociative recombination is found to be the primary production route for these molecules, and reactions with abundant ions are found to be the primary destruction routes. H + CH3NC is investigated with transition state theory as a potential destruction route, but found to be too slow in cold cloud conditions to account for the discrepancy in modelled and observed abundances of CH3NC.