Mixture Of Ether Research Articles

Visible-Light-Induced Three-Component Reactions of α-Diazoesters, Indazoles and Cyclic Ethers

An efficient method was developed for construction of N-short-chain ether attached carbonyl group-substituted indazoles. The visible-light-induced three-component reactions of α-diazoesters, indazoles and cyclic ethers, under extremely mild conditions, led to the corresponding mixture of N1 and N2 short-chain ether substituted indazoles in good to excellent yields.

Simultaneous extraction and quantification of hydrophilic and lipophilic antioxidants in Solanum lycopersicum L. varieties marketed in Saudi Arabia

Abstract Several varieties of Solanum lycopersicum L. are consumed in Saudi Arabia, including the most expensive Ramis tomato, which is claimed to be rich in antioxidants. However, there is a lack of studies on the extraction and quantification of antioxidants in tomatoes marketed in Saudi Arabia. Therefore, this study aimed to develop a straightforward method to extract and quantify phenolics and carotenoids in tomatoes consumed in Saudi Arabia. The developed method used glass coverslips for homogenisation and a methanol-petroleum ether mixture for extraction. In 15 investigated varieties, antioxidants were abundantly present in the skin part (2.0 ± 0.72 mg/g of phenolics and 229.50 ± 21.10 μg/g of carotenoids) compared to the pulp (0.67 ± 0.20 mg/g of phenolics and 107.70 ± 21.10 μg/g of carotenoids). Generally, the Saudi varieties contained higher amounts of antioxidants than the imported varieties. The antioxidant content of the Ramis cultivar depends on the cultivation location. For instance, Ramis Awjam shows high amounts of phenolics (2.72 mg/g in the skin extract and 0.63 mg/g in the pulp) and carotenoids (338.04–388.41 μg/g in the skin and 173.93–205.75 μg/g in the pulp). This study provides valuable insights that can assist in selecting the cultivar and location of tomatoes with the maximum antioxidant quantities.

Stage-wise kinetic analysis of ammonia addition effects on two-stage ignition in dimethyl ether

Abstract Ammonia (NH3) has gained considerable attention as a promising carbon-free hydrogen carrier fuel for internal combustion engines, but its direct use in compression-ignition engines presents challenges, often requiring high-reactivity fuels to ignite the premixed NH3/air mixture and initiate combustion. This study focuses on the ignition process of binary NH3 and dimethyl ether (DME) mixtures, as DME is a carbon-neutral, high-reactivity fuel. A key novelty of this paper is the comparison of the ignition processes of DME and NH3/DME mixtures from a temporal, process-oriented perspective, analyzing chemical kinetics across distinct ignition phases rather than focusing solely on instantaneous reactions at discrete time points. The stage-wise analysis reveals that NH3 has minimal impact on the control mechanism governing the two-stage ignition process of DME. Specifically, DME still largely depends on OH radical proliferation during low-temperature oxidation (LTO), which releases heat as the reaction progresses. As the temperature increases, LTO branching pathways gradually shift to chain-propagation pathways, reducing overall reaction activity. The reactivity and temperature rise rate of the system are then governed by the H2O2 loop mechanism before thermal ignition. However, ammonia significantly extends the ignition delay of DME by competing with OH radicals, which are critical for DME oxidation, thus inhibiting ignition. As the ignition reaction proceeds, ammonia kinetics become more involved. For example, nitrogen-containing species from NH3 oxidation, such as NO, NO2, and NH2, react with CH3OCH2 to form CH3OCHO, reducing the flux through the LTO pathway of DME. While ammonia reaction pathways also produce OH radicals, this occurs at the expense of HO2 and H radicals, leading to H2O2 formation. Overall, these findings demonstrate the substantial impact of ammonia addition on DME ignition, highlighting the need for further research to better understand NH3/DME binary fuel ignition and to optimize the design and operation of NH3/DME dual-fuel engines for improved efficiency and reliability.

Experimental results on a chiller using a CO2-DME mixture

CO2-DME (Carbon Dioxide-Dimethyl Ether) mixtures raised our interest in the last year as they promise to increase the COP with respect to pure CO2 while maintaining GWP = 1. The mixture can be non-flammable, as far as the percentage of DME is low. This study presents experimental findings obtained from a chiller system utilizing CO2-DME mixtures as the working fluid. The experimental investigation aims to analyse the performance and behaviour of the chiller under varying operating conditions. Key parameters, such as coefficient of performance, cooling capacity, and thermodynamic behaviour are examined to assess the suitability and efficacy of the CO2-DME mixture in chiller applications. The experimental results shed light on the thermodynamic characteristics and operational considerations of the chiller system, providing valuable insights into the potential of CO2-DME mixtures for environmentally friendly, safe and energy-efficient cooling technologies. The experimental findings indicate a maximum increase in COP of 15 % for a mixture comprising 10 % DME, with a condensation temperature of 35 °C. Furthermore, the cooling capacity is reduced only by 7 % in the worst case.

Exposure to an environmentally representative mixture of polybrominated diphenyl ethers (PBDEs) alters zebrafish neuromuscular development

Polybrominated diphenyl ethers (PBDEs) are a prevalent group of brominated flame retardants (BFRs) added to several products such as electronics, plastics, and textiles to reduce their flammability. They are reported as endocrine disruptors and neurodevelopmental toxicants that can accumulate in human and wildlife tissues, thus making their ability to leach out of products into the environment a great cause for concern. In this study, zebrafish (Danio rerio) embryos and larvae were exposed to a wide concentration range (1.5, 15, 150 and 300 pM) of a PBDE mixture from one to six days post-fertilization (dpf). Hatching rates, mortality and general morphology were assessed during the exposure period. A delay in hatching was observed at the two highest PBDEs concentrations and mortality rate increased at 6 dpf. By 4 dpf, larvae exposed to 150 pM and 300 pM PBDEs developed an upcurved phenotype. Analysis of motor behavior at 6 dpf revealed that PBDE exposure acutely reduced locomotion. To further analyze these motor deficits, we assessed the neural network density and motor neuron and neuromuscular junctions (NMJ) development by immunostaining and imaging. Acetylated α-tubulin staining revealed a significant loss of neurons in a dose-dependent manner. Synaptic vesicle protein 2 (SV2) and ⍺-bungarotoxin (⍺-BTX) staining revealed a similar pattern, with a significant loss of SV2 and nicotinic acetylcholine receptors, thus preventing the colocalization of presynaptic neurons with postsynaptic neurons. Consistent with these results, the presence of cleaved caspase-3 and acridine orange positive cells showed increased cell death in zebrafish larvae exposed to PBDEs. Our results suggest that exposure to PBDEs leads to deficits in the zebrafish neuromuscular system through neuron death, inducing morphological and motor deficiencies throughout their development. They provide valuable insight into the neurotoxic effects of PBDEs, further highlighting the relevance of the zebrafish model in toxicological studies.

Composition and Activities of Carpesium macrocephalum Franch. & Sav. Essential Oils

Carpesium macrocephalum, a species native to China, Korea, Japan, and Russia, has been used medicinally in the countries of its origin. Though mono- and sesquiterpenoids are known constituents of C. macrocephalum, the complete analysis of essential oils produced by the roots and aerial parts of the plant has not been published until now. The present study discloses considerable differences in the composition and cytotoxic activity of essential oils distilled from roots and shoots of C. macrocephalum. The GC-MS-FID analyses have led to the identification of 131 compounds in all, of which 114 were found in aerial parts and 110 in the roots of the plants. The essential oil distilled from shoots contained a mixture of nerol and thymol methyl ether (c. 26%), neryl isobutyrate (c. 12%) and linalool (c. 9%) as major constituents, whereas alantolactone (c. 29%), thymol methyl ether (c. 7%) and 2,5-dimethoxy-p-cymene (thymohydroquinone dimethyl ether, c. 7%) predominated in the essential oil obtained from the roots. The oils demonstrated weak antibacterial activity against Staphylococcus aureus and, at concentrations up to 2.08 mg/mL (oil from the aerial parts) and up to 3.38 mg/mL (oil from roots), were inactive against Gram-negative bacteria. The essential oil from the roots of the plant demonstrated strong but not selective cytotoxic activity.

Synthesis and characterization of a novel eight-membered cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane and 4,4ˈ-bipyridine, 1D adduct

Simple adducts of cyclo-diboradisiloxanes (Lewis acid) and amines (Lewis base) have been reported in the literature. However, the method for the synthesis of an 8-membered cyclo-diboratetrasiloxane, as well as its adducts, was modified in this report to save cost and achieve new results. In the literature, the synthesis of cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane (Ph6B2Si2O4) (3) has been reported using diphenylsilanediol and phenylboronic acid and a Dean-Stark apparatus for the removal of water. However, in this study, molecular sieves were used for the facile removal of water, and the crude product recrystallized from diethyl ether and petroleum ether (3:1 ratio) to give compound 3. Compound 3 was reacted with 4,4’-bipyridine in a mixture of diethyl ether and petroleum ether solvents at reflux to give a 1D polymer [Ph6B2Si2O4]·L1 (4). Furthermore, compound 4 was characterized with various characterization methods such as single-crystal XRD, nuclear magnetic resonance, and FT-IR spectroscopy. The single crystal X-ray diffraction studies shows that the title compound crystalizes in the triclinic crystal system in the centrosymmetric space group P-1, a = 10.9372(4) Å, b = 18.4221(6) Å, c = 19.4697(6) Å, α = 70.533(3)°, β = 86.476(3)°, γ = 88.517(3)°, V = 3691.6(2) Å3, Z = 2, T = 173.0 K, μ(MoKα) = 0.122 mm-1, Dcalc = 1.204 g/cm3, 21463 reflections measured (5.196° ≤ 2Θ ≤ 56.45°), 14525 unique (Rint = 0.0185, Rsigma = 0.0483) which were used in all calculations, the final R1 was 0.0721 (I > 2σ(I)) and wR2 was 0.2143 (all data) with the 8-membered cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane (Ph6B2Si2O4) (3) configuration.

Nickel-Catalyzed C-C Activation of Vinylcyclobutane with Visible Light: Scope, Mechanism, and Application to Chemically Recyclable Polyolefins.

N-heterocyclic carbene (NHC)-supported nickel complexes were investigated for the oxidative ring-opening of vinylcyclobutane (VCB) and photocatalytic activity. Addition of VCB to in situ generated [(NHC)Ni(0)] compounds furnished (NHC)Ni(VCB)2 that underwent oxidative addition and conversion to the corresponding Ni(II) alkyl, allyl-metallacycles. The (NHC)Ni(C6H10) metallacycles were isolated, characterized, and exhibited high thermal and chemical stability. Irradiation with visible light at ambient temperature produced a mixture of ethylene and 4-vinylcyclohexene and 1,5-cyclooctadiene, cycloaddition dimers of butadiene, arising from formal retro-[2 + 2] cycloaddition. A mixture of hexadiene products arising from β-H elimination from the metallacycle was also observed. Free ethylene also underwent a secondary reaction to form cyclopropane products through formal [2 + 1] cycloaddition. A series of sterically and electronically modified NHC ligands was evaluated to establish the structure-activity relationship governing the rate of photocatalytic conversion of VCB and the resulting product distribution. Isotopic labeling experiments, resting state analysis, and independent synthesis of a range of nickel bis(olefin) complexes provided insight into the mechanism of the reaction and origins of the organic product mixture. (NHC)Ni-catalysis was also applied toward the retro-[2 + 2] depolymerization of (1,n'-divinyl)-oligocyclobutane to butadiene dimers.

Turbulent pipe flow and heat transfer of a binary mixture at supercritical pressure: Influences of cross-diffusion effects

Cross-diffusion effects, including Soret and Dufour effects, are enhanced around the pseudo-critical temperature (Tpc) of a binary mixture. Their influences on heat transfer at supercritical pressure have been scarcely studied. To bridge this gap, large-eddy simulations (LES) are conducted to investigate forced convective heat transfer of a CO2–ethane mixture at supercritical pressures in a circular pipe subject to a uniform heat flux. Both heating and cooling conditions, along with varying initial concentrations and thermodynamic pressures, are included in the simulations. The LES results reveal that the Soret effect causes concentration separation, resulting in a concentration boundary layer. The magnitudes of the thermodiffusion factor (kT) and the radial temperature gradient control the intensity of separation, which is more pronounced at near-critical pressure and high heat flux. Since kT is significant only around Tpc, downstream decay of the concentration separation is observed as the loci of T=Tpc migrate away from the wall so that the local radial temperature gradient diminishes. The primary factors affecting heat transfer are the variations in thermal conductivity and isobaric specific heat resulting from concentration separation. In contrast, the Dufour effect and the accompanying inter-diffusion play negligible roles. In deterioration scenarios, the bulk Nusselt number (Nub) shows a maximum relative drop of 8%, whereas in enhancement scenarios, Nub shows a maximum relative increase in 10%, with both deterioration and enhancement decaying downstream. Cross-diffusion effects have negligible impacts on density and streamwise velocity, but noticeably alter streamwise velocity fluctuation and turbulent kinetic energy.

Density, Viscosity, Spectra and Quantum Chemistry Analysis of Dimethyl Sulfoxide and Ethylene Glycol Propyl Ether Mixtures

Density, Viscosity, Spectra and Quantum Chemistry Analysis of Dimethyl Sulfoxide and Ethylene Glycol Propyl Ether Mixtures

Development of a Screening Platform for Optimizing Chemical Nanosensor Materials.

Chemical sensors, relying on changes in the electrical conductance of a gas-sensitive material due to the surrounding gas, typically react with multiple target gases and the resulting response is not specific for a certain analyte species. The purpose of this study was the development of a multi-sensor platform for systematic screening of gas-sensitive nanomaterials. We have developed a specific Si-based platform chip, which integrates a total of 16 sensor structures. Along with a newly developed measurement setup, this multi-sensor platform enables simultaneous performance characterization of up to 16 different sensor materials in parallel in an automated gas measurement setup. In this study, we chose the well-established ultrathin SnO2 films as base material. In order to screen the sensor performance towards type and areal density of nanoparticles on the SnO2 films, the films are functionalized by ESJET printing Au-, NiPt-, and Pd-nanoparticle solutions with five different concentrations. The functionalized sensors have been tested toward the target gases: carbon monoxide and a specific hydrogen carbon gas mixture of acetylene, ethane, ethne, and propene. The measurements have been performed in three different humidity conditions (25%, 50% and 75% r.h.). We have found that all investigated types of NPs (except Pd) increase the responses of the sensors towards CO and HCmix and reach a maximum for an NP type specific concentration.

Combustion Test for the Smallest Reciprocating Piston Internal Combustion Engine with HCCI on the Millimeter Scale

Micro reciprocating piston internal combustion engines are potentially desirable for high-energy density micro power sources. However, complex subsystem functions hinder the downsizing of reciprocating piston internal combustion engines. The homogeneous charge compression-ignition (HCCI) combustion mode requires no external ignition system; it contributes to structural simplification of the reciprocating piston internal combustion engines under a micro space constraint but has not been adequately verified at the millimeter scale. The study used a millimeter-scale HCCI reciprocating piston internal combustion engine fueled by a mixture of kerosene, ether, castor oil, and isopropyl nitrate for combustion investigation. The test engine with a displacement of 0.547 cc is the smallest reciprocating piston internal combustion engine known to have undergone in-cylinder combustion diagnosis. It is observed that the HCCI combustion mode at the millimeter scale can realize stable combustion with excellent cooperation for the thermodynamic cycle under appropriate structural and operating conditions, which is essentially not inferior to those in conventional-sized reciprocating piston internal combustion engines. This finding helps the next step of scaling down reciprocating piston internal combustion engines.

In‐situ preparation of modified‐halloysite/thermoset nanocomposites via thiol‐epoxy click chemistry

AbstractIn the current study, thermoset nanocomposites including halloysite nanotubes (HNTs) have been prepared through thiol‐epoxy click reaction at ambient conditions. Naturally available HNTs are first modified separately by epoxy and thiol groups and used as nanofillers in a mixture of trimethylolpropane triglycidyl ether and trimethylolpropane tris(3‐mercaptopropionate) ranging from 0 to 5 wt%. Fourier transformed infrared (FT‐IR) spectroscopy has been used to observe the characteristic bands of the pure and modified halloysite, neat thermoset, and HNT/thermoset nanocomposites. Thermal properties of epoxide‐modified and thiol‐modified halloysite nanotubes and also final thermoset nanocomposites have been investigated using thermogravimetric analysis (TGA) by comparing pure halloysite and neat thermoset, respectively. The dispersion of HNT nanotubes in thermoset matrix has been examined with scanning electron microscopy (SEM). In addition to the agglomerated/non‐agglomerated distribution, the present of HNT has been proved by EDX. The effect of HNT‐Epoxide and HNT‐Thiol loadings on mechanical properties has been examined by tensile test. All nanocomposites were found to exhibit better tensile strength than that of neat thermoset, called as reference sample. The most enhanced mechanical properties have been detected in the nanocomposite with 3% modified‐HNTs by weight because of the best dispersion, which promotes effective interactions between the nanotubes and thermoset matrix. Tensile strength of thermoset nanocomposites increased by 43% and 62%, while elongation at break increased by 58% and 149% when 3 wt% HNT‐Epoxide and 3 wt% HNT‐Thiol were added to the matrix, respectively. Further increase of HNT added to the matrix causes agglomeration of nanotubes and thus deterioration of mechanical properties.Highlights Pure HNT was modified and successfully converted into HNT‐Epoxide and HNT‐Thiol. In‐situ preparation of thermoset nanocomposites with modified‐HNTs was effectively achieved via thiol‐epoxy click chemistry. Mechanical properties increased significantly with both HNT‐Epoxide and HNT‐Thiol loading ratio up to 3 wt%. The presence and agglomerated/non‐agglomerated dispersion of modified‐HNTs in the thermoset matrix were verified by SEM–EDX analysis.

Control of extractive distillation processes with preconcentration for the separation of ternary azeotropic mixture ethyl acetate-ethanol–water in the face of multiple feed disturbances

The integration of preconcentration and solvent recovery functions is one of the effective ways to save energy consumption of extractive distillation processes for separating ternary azeotropic mixtures with a high content of one composition. However, the integration of various functions inevitably increases the difficulty of constructing robust control structures. In this paper, different proportion-integration (PI) control structures are investigated for the four-column extractive distillation with preconcentration process, while different PI and PI with model prediction controller (MPC) hybrid control structures are proposed for the three-column extractive distillation with integrated distillation column (TCED-IDC) process to deal with feed disturbances via taking the separation of ternary azeotropic mixture ethyl acetate-ethanol–water as a case study. The control structures are tested via introducing multiple feed disturbances including one feed flowrates disturbance and three feed compositions disturbances. The dynamic test comparison results show that the integration of preconcentration and solvent recovery functions causes a larger transient deviation in terms of dynamic responses of the individual optimal control structures. In addition, the integral of squared error of the TCED-IDC process are reduced by about 22 times after introducing the MPC in the face of feed disturbances.

Experimental validation of RE170 / R600 (Dimethyl Ether / Butane) mixture as a superior refrigerant compared to R600a (Isobutane)

Isobutane (R600a) is the most used refrigerant for low-capacity refrigeration systems, as it combines excellent environmental properties and offers good energy performance. A real possibility to increase the efficiency of these systems is using new refrigerant mixtures offering energy improvements (being compatible with existing systems). This work, from an experimental perspective, proposes mixtures of dimethyl ether and butane (RE170/R600) as potential drop-in refrigerants of R600a systems. For a given operating condition, the energy performance of RE170/R600 mixtures with maximum proportion of 27.5 % of RE170 has been tested using a water-to-water single-stage compression cycle, measuring COP increments from 10.1 to 17.6 % in relation to R600a. Then, the blend RE170/R600 (15/85 %), considered as the potential drop-in fluid of R600a, has been tested in a wide range of operating conditions, concluding that it offers the same cooling capacity than R600a but with COP increments from 12.6 % to 17.6 %.

Study of sertraline solubility, solvent effect, and modeling in the aqueous mixtures of dimethyl sulfoxide or diethylene glycol monoethyl ether at several temperatures and its use in the formulation of nanosuspensions

The solubility profile of a weakly water-soluble drug of sertraline (SRT) at the temperature range of 298.2–318.2 K under atmospheric pressure, in the binary aqueous mixtures of dimethyl sulfoxide (DMSO) and diethylene glycol monoethyl ether (DEGMEE) was measured using a shake-flask method. As a result, SRT was discovered to have the maximum solubility in DMSO among investigated solvent systems. The obtained solubility values were correlated by utilizing cosolvency models, including the Jouyban-Acree-van't Hoff and Jouyban-Acree models, and the mean relative deviations were computed in order to evaluate the precision of these equations. Additionally, using the van't Hoff and Gibbs formulas at Thm, the parameters of apparent thermodynamics (Gibbs energy, entropy, and enthalpy) of SRT in the saturated mixtures were calculated. According to these solubility results, SRT nanosuspensions, which had a mean particle size of under 200 nm, were formulated in DMSO and water as a solvent combination. Therapeutic development could be significantly improved by implementing solubilization strategies for enhancing the bioavailability of medicines that are only weakly water-soluble, according to the results of the experimental and statistical assessment of solubility.

Total syntheses of borolithochromes H1, H2, I1, and I2.

Total syntheses of borolithochromes H1, H2, I1, and I2, the red pigments isolated from fossils of Jurassic putative red alga Solenopora jurassica, have been achieved. The naphthoquinone possessing a chiral sec-butyl side chain has been synthesized from (S)-2-methylbutanol. The Diels-Alder reaction of the chiral naphthoquinone and the previously reported diene was followed by one pot S-methylation/intramolecular Corey-Chaykovsky reaction/epoxide rearrangement to provide the benzo[gh]tetraphene skeleton. Complexation of the resulting ligand with trimethyl borate and the following O-demethylation furnished a 1:1 mixture of borolithochromes I1 and I2, which were separated by HPLC using CHIRALPAK IC® to afford optically pure borolithochromes I1 (6) and I2 (7). On the other hand, borolithochromes H1 and H2 were not separated by HPLC in our laboratory. Fortunately, the mixture of the methyl ethers of borolithochromes H1 and H2 were separated and O-demethylation with magnesium iodide furnished optically pure borolithochromes H1 (4) and H2 (5).

ETHYLENE CONVERSION IN A BARRIER DISCHARGE: EXPERIMENT AND MODELING

The selective conversion of ethylene and its mixtures with argon and air in a barrier discharge has been studied. Plasma chemical transformation proceeds without the formation of polymer-like substances or products of deep oxidation to oxygen-containing compounds and various saturated and unsaturated hydrocarbons. Synthesis is carried out on a set-up with a gas-liquid reactor in the presence of water, which ensures the elimination of formed substances from the discharge area and prevents repeated exposure to barrier discharge plasma. The treatment of ethylene in a barrier discharge leads to the formation of saturated and unsaturated hydrocarbons C1–C5+ with a predominance of compounds with four carbon atoms in the molecule, the total content of which in the reaction products reaches 58.4 wt.%. The addition of argon to ethylene does not significantly affect the set and content of substances in the reaction products, an increase in ethylene conversion is observed, the maximum value of which reaches 58.9 wt.%. The treatment of a mixture of ethylene with air additives leads to the formation of hydroxyl and carboxyl compounds with a total content of ~29 wt.% in the products, and saturated and unsaturated hydrocarbons C1–C4 with a predominant acetylene content up to ~47 wt.%. The conversion of ethylene in one pass of the reaction mixture through the reactor under these conditions is 12.8 wt.%. When evaluating the energy losses of barrier discharge electrons in electron-molecular interactions during the conversion of ethylene, it was found that 78% of the energy of barrier discharge electrons is spent mainly on excitation of the electronic states of ethylene molecules, and argon additives can increase it to 86%. In the case of conversion of ethylene mixtures with air additives, it is shown that only ~14% of the discharge energy is spent on the excitation of the electronic states of the ethylene molecule, and the main amount (65%) is spent on the excitation of various different states of nitrogen molecules. The data obtained were used to develop a model of the chemical kinetics of ethylene conversion in a barrier discharge. The proposed model contains more than 280 reactions and is in good agreement with experimental data. As a result of the simulation, new data were obtained on the behavior of an ethylene molecule in a barrier discharge plasma with an average electron energy of 4-5 eV. The results obtained will be useful in the development of modern ethylene processing methods focused on the technological simplicity and compactness of the chemical process that meets the principles of "green chemistry" and low carbon footprint in the environment. For citation: Ryabov A.Yu., Kydryashov S.V. Ethylene conversion in a barrier discharge: experiment and modeling. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 6-14. DOI: 10.6060/ivkkt.20246708.12t.

Equilibrium solubility and mathematical modelling of glibenclamide in cosolvent mixtures of glycols and alcohols

ABSTRACT Glibenclamide (GBN) is a commonly used oral medication for treating type-II diabetes that acts by reducing high blood sugar levels. The effectiveness of GBN depends on the quality of the product. The quality is influenced by the solubility properties of a drug. This study aimed to measure the solubility of GBN in various solvent mixtures including some glycols and alcohols. The solubility was determined using a shake-flask method at 298.2 K under atmospheric pressure. The results showed that GBN had the highest solubility in ethylene glycol monomethyl ether and alcohol mixtures compared to the other tested glycols.

The influence of structure of carbon nanofibers on their interaction with polyethylene matrix

The development of methods for purposeful modification of the polyethylene matrix with carbon nanostructures to create stronger and more durable pipe composites is an important direction in polymer science. Carbon nanofibers (CNFs) of three types, obtained via catalytic chemical vapor deposition of ethylene (Type I), trichloroethylene (Type II), and a mixture of ethylene and acetonitrile (Type III), were applied as modifying additives to improve the physical and mechanical characteristics of polyethylene. The polyethylene/CNF composites were prepared using a laboratory plasticizer. The introduction of CNFs (Type I) with a densely packed structure into the polymer matrix was found to provide the formation of a uniform fine-spherulitic structure that results in increased tensile strength, yield strength, elastic modulus, and abrasive wear. Such a positive effect is observed when the CNF content in the composite does not exceed 1.0 wt%. An increase in the abrasion resistance by a factor of 1.6 was observed.