Mixture Of Ether Research Articles

Accelerated ignition-shock coupling and deflagration to detonation transition by ozone kinetic enhancement of dimethyl ether mixture

This study aims to understand the effect of kinetic enhancement by ozone addition on the Deflagration to Detonation Transition (DDT) and ignition-shock coupling in a microchannel using dimethyl ether (DME). Simultaneous high-speed chemiluminescence and shadowgraph imaging are carried out to analyze the flame front propagation, shock wave structures, autoignition, and ignition-shock coupling during the DDT process. The experimental results show that for all cases, with and without ozone kinetic enhancement, autoignition and DDT always occur in a reactivity gradient region with oblique shock cluster between the flame front and the flame acceleration-induced precursor shock. The observed DDT occurs via the Zeldovich hot spot gradient mechanism through the following stages: (1) Oblique shock cluster formation and acoustic compression between the flame front and the precursor shock, (2) autoignition initiation in the oblique shock cluster region, (3) spontaneous ignition wave propagation, and (4) ignition-shock coupling. It is found that autoignition location, oblique shock strength, induction zone length, ignition-shock coupling, and DDT onset flame velocity are very different from ozone kinetic enhancement. As the ozone addition is higher, the autoignition is advanced and the ignition location moves farther ahead of the flame front at a lower flame front propagation speed and weaker oblique shock clusters. Two different ignition-shock coupling modes are identified depending on ozone concentration. Without ozone kinetic enhancement, DDT occurs via ignition wave coupling with the precursor shock. However, ozone addition can accelerate the autoignition and initiate a direct ignition-shock coupling for DDT without interaction with the precursor shock. The present results show that kinetic enhancement in autoignition using an ignition enhancer such as ozone or plasma is critical and effective in accelerating and controlling DDT.

Steady states and kinetic modelling of the acid-catalysed ethanolysis of glucose, cellulose, and corn cob to ethyl levulinate.

Ethyl levulinate is a promising advanced biofuel and platform chemical that can be derived from lignocellulosic biomass by ethanolysis processes. It can be blended with both diesel and gasoline and, thus, used in conventional engines and infrastructure. Previously, it has been shown that alkyl levulinate/alcohol/alkyl ether mixtures exhibit significantly enhanced fuel properties relative to any of the individual fuel components, particularly when blended with conventional hydrocarbon liquid fuels. Consequently, this study specifically quantifies the three primary components of the alcoholysis reaction mixture: ethyl levulinate, diethyl ether, and ethanol. The steady state and kinetic phase fractions of ethyl levulinate and diethyl ether produced from glucose, cellulose, and corn cob with 0.5-2 mass% sulphuric acid in ethanol are determined for 5, 10, and 20 mass% of feedstock at 150 °C. Knowledge of the steady state equilibrium mixture fraction is specifically targeted due to its importance in assessing commercial-scale production and in modelling analysis as: (i) it defines the maximum yield possible at a given condition, and (ii) it is equitable to the minimum free energy state. Maximum steady state yields (mass%) of ethyl levulinate of (46.6 ± 3.7), (50.2 ± 5.4), and (27.0 ± 1.9)% are determined for glucose, cellulose, and corn cob, respectively. The conversion of glucose and cellulose to ethyl levulinate in the presence of ethanol and sulphuric acid is shown to be a catalytic process, where the ethyl levulinate yield is not dependent on the acid concentration. For corn-cob biomass, in a new and contrasting finding, the ethyl levulinate yield is shown to strongly depend on the acid concentration. This effect is also observed in the fractions of diethyl ether formed, providing strong evidence that the hydrogen cation is not being replenished in the ethanolysis process and the overall reaction with corncob is not wholly catalytic. Thus, for the acid catalysed alcoholysis of lignocellulosic biomass, acid concentration must be scaled with feedstock concentration. The critical corn cob-to-acid ratio that maximises ethyl levulinate yields while minimizing the formation of undesired co-products (diethyl ether) is in the range 10-20 : 1 at 150 °C. A detailed, hierarchical, mass-conserved chemical kinetic model capable of accurately predicting the relative abundance of the three primary components of the ethanolysis reaction: ethyl levulinate, diethyl ether, and ethanol, from the biochemical composition of the feedstock, is elucidated and validated.

Non-Flammable Ether and Phosphate-Based Liquid Electrolytes for Sodium-Ion Batteries

The demand on the lithium reserves has been increasing rapidly due to the continuous growth in energy storage devices. Since the lithium reserves are limited and only accessible at certain geographical areas, the costs of lithium precursors are increasing significantly.1 Therefore, alternative battery chemistries need to be investigated. One of the next generation battery solutions is sodium-ion batteries (SIBs).2 However, current commercial electrolytes in SIBs are based on highly flammable carbonate-based solvents, such as ethylene carbonate, propylene carbonate, diethyl carbonate and dimethyl carbonate.3 To enhance the safety of SIBs, it is of utmost importance to develop non-flammable electrolytes. In this work, NaPF6 and NaBF4 salts are used in combination with a solvent mixture of ethers (diglyme, tetraglyme) and phosphates (triethylphosphate, trimethylphosphate) to obtain non-flammable liquid electrolytes. The electrolytes are evaluated in terms of physicochemical properties and electrochemical performance full-cells using high-mass loading Prussian White (12 mg/cm2) and Hard Carbon (7 mg/cm2). Flammability tests have shown that at least 70% of phosphate co-solvents are required to make the glyme based electrolyte non-flammable. In summary, the combination of glymes and phosphates provide promising electrolyte formulations in terms of non-flammability characteristics and ionic conductivities, but still lack long-term cycling stability. This work opens avenues to optimizing non-flammable electrolytes for high-performing and safe SIBs. References 1 R. Schmuch, R. Wagner, G. Hörpel, T. Placke and M. Winter, Nat. Energy, 2018, 3, 267–278.2 H. S. Hirsh, Y. Li, D. H. S. Tan, M. Zhang, E. Zhao and Y. S. Meng, Adv. Energy Mater., 2020, 10, 1–8.3 R. Gond, W. Van Ekeren, R. Mogensen, A. J. Naylor and R. Younesi, Mater. Horizons, 2021, 8, 2913–2928. Acknowledgement The authors would like to acknowledge the financial support by the Swedish Energy Agency via project no. 50177-1, VINNOVA via projects no. 2022-01465 and 2019-00064 (Batteries Sweden), and SuSaNa project under M-ERA-Net call 2021 (G.A. no 958174).

Free-Standing 3D Printing of Epoxy-Vinyl Ether Structures Using Radical-Induced Cationic Frontal Polymerization.

The application of frontal polymerization to additive manufacturing has advantages in energy consumption and speed of printing. Additionally, with frontal polymerization, it is possible to print free-standing structures that require no supports. A resin was developed using a mixture of epoxies and vinyl ether with an iodonium salt and peroxide initiating system that frontally polymerizes through radical-induced cationic frontal polymerization. The formulation, which was optimized for reactivity, physical properties, and rheology, allowed the printing of free-standing structures. Increasing ratios of vinyl ether and reactive cycloaliphatic epoxide were found to increase the front velocity. Addition of carbon nanofibers increased the front velocity more than the addition of milled carbon fibers. The resin filled with carbon nanofibers and fumed silica exhibited shear-thinning behavior and was suitable for extrusion-based printing at a weight fraction of 4 wt %. A desktop 3D printer was modified to control resin extrusion and deposition with a digital syringe dispenser. Flexural properties of molded and 3D-printed specimens showed that specimens printed in the transverse direction exhibited the lowest strength, likely due to the presence of voids, adhesion issues between filaments, and preferential carbon nanofiber alignment along the filaments. Finally, free-standing printing of single, angled filaments and helical geometries was successfully demonstrated by coordinating ultraviolet-based reaction initiation, low air pressure for resin extrusion, and printing speed to match front velocity.

Volumetric, acoustic, and optical properties of binary mixtures of diethyl ether with alkanol at T = 293.15 K to 303.15 K

Density (ρ), ultrasonic speed (u), and refractive index (nD) of binary liquid mixtures such as diethyl ether (DEE) (1) + alkanol (isomers of propanol and 1-butanol) (2) were experimentally measured at T = 293.15 K to 303.15 K and at 0.1 MPa pressure. By using these measurements excess molar volume (VmE), deviation in ultrasonic speed (Δu), excess isentropic compressibility (κsE), and deviation in refractive index (ΔnD) were computed and associated with the Redlich-Kister polynomial equation. It was found that deviation parameters are influenced by H–bonding, interstitial accommodation, and dipole–dipole molecular interactions between binary mixtures. The VmE values have been interpreted by the Prigogine–Flory–Patterson (PFP) theory and the Flory–Treszczanowicz–Benson (FTB) model. The FTB model and PFP theory anticipated the VmE curves and were able to depict the perfect shape and magnitude of VmE values. The numeric values of u and nD were computed by using several empirical correlations and mixing rules. This study discusses the comparative significance of these relationships with the measured values of u and nD.

Experimental and mechanism study on the flammability of the mixtures of propylene and ethane

In the background of the global promotion of green and low-carbon transition, more attention should be paid to the combustion characteristics of environmentally friendly but flammable working fluids. This study delves into the flammability of mixtures composed of propylene (R1270) and ethane (R170) with 1,1,2,3,3,3-hexafluoro-1-propene (R1216) and 1,1,1,2-tetrafluoroethane (R134a). The flammability limit ranges of these four mixtures were measured at different concentrations. The flammability inhibition effects of R1216 and R134a on hydrocarbon (HC) working fluid R1270 were then compared and analysed under different temperature conditions. Additionally, the density functional theory (DFT) method was employed to analyse the interaction mechanisms of HCs/R1216 and HCs/R134a. The results show that, firstly, low proportional concentrations of R1216 and R134a widen the flammability limit ranges of mixtures HCs/R1216 and HCs/R134a. Moreover, elevated temperatures not only promote the combustion reactions of HCs but also facilitate the thermal decomposition reactions of R1216 and R134a. However, HCs are more sensitive to temperature changes. Therefore, the flammability limit range of mixtures expands as the temperature rises. Secondly, a combination of theoretical calculations and experiments demonstrates that R134a exhibits better physical flame retardancy than R1216, while the chemical flame retardancy of R1216 is superior to that of R134a. These results provide a valuable reference for the safe application of hydrocarbon working fluids.

Ethane-CO2 Mixture Adsorption in Silicalite: Influence of Tortuosity and Connectivity of Pores on Selectivity

Selective adsorption using nanoporous materials is an efficient strategy for separating gas mixtures. In a nanoporous material, pores can exist in different shapes and can have different degrees of inter-connectivity. In recent studies, both pore connectivity and tortuosity have been found to affect the adsorption and dynamical properties of ethane and CO2 in silicalite differently. Here, using Monte Carlo simulations, we investigate if these two attributes can affect the selective adsorption of one component from a mixture of ethane and CO2 in silicalite. For this, the adsorption of an equimolar mixture of ethane and CO2 is simulated in 12 models of silicalite—SnZm (n, m = 0, 1, 2, 3 or 4; with n and m denoting, respectively, the fraction (out of 4) of straight and zigzag channels of silicalite that are available for adsorption)—differing in degrees of pore connectivity and tortuosity. The adsorption selectivity in this system is found to exhibit a reversal with the adsorption dominated by ethane at low pressures (below ~1 atm) and by CO2 at higher pressures (above ~10 atm). Pore connectivity is found to suppress the selective adsorption of CO2 at higher pressures and also shifts the selectivity reversal to higher pressures. The selectivity reversal results from a competition between the polarizability-affected adsorption at lower pressures and efficient packing at higher pressures. The efficient packing of CO2 is a compounded effect resulting from the larger effective pore volume available for CO2 due to its stronger interaction with the pore surface and smaller molecular volume. CO2 molecules show a preference to adsorb in non-tortuous pores, and this preference is found to be stronger in the presence of ethane. The effects of pore connectivity and tortuosity elucidated here should be applicable to a wide range of natural and engineered nanoporous materials, and this knowledge could be used to identify materials with better capability for separating and storing CO2 based on their pore attributes.

A Practical and Scalable Non‐Photonic Decarboxylative C−N Coupling of Bicyclo[1.1.1]Pentane Carboxylate by Leveraging High Throughput Experimentation

AbstractResearch towards the development of novel synthetic methods to access substituted bicyclo[1.1.1]pentane (BCP) structural motifs has been conducted by both academic groups and industrial organizations. Recent developments have been strongly focused on the utility of visible light catalysis to promote a cornucopia of radical‐based transformations, including incorporation of BCP motifs. While these methods have proven powerful in accessing various substitution patterns, some scalability challenges remain. Herein we describe a focused effort on the high‐throughput experimentation (HTE) guided optimization of a decarboxylative non‐photonic coupling that can be conducted using traditional batch reactors. Employing an unanticipated mixture of copper(I) chloride and cyclopentyl methyl ether (CPME) results in the formation of a N‐substituted bicyclo[1.1.1]pentyl pyrazole product while limiting the overall equivalency of the hypervalent iodonium precursor.

Sensitive and Rapid LCMS/MS Method for the Estimation of recently approved Antiviral drugs Maribavir and Fostemsavir in spiked human plasma

In this study, a straightforward, highly sensitive, and selective liquid chromatography/tandem mass spectrometry (LC–MS/MS) method was developed and rigorously validated for the simultaneous quantification of Maribavir and Fostemsavir in human plasma. To ensure precision and reliability, we employed Dolutegravir as the internal standard (IS). The analytical process involved a two-step extraction method. Initially, protein precipitation was induced by the addition of acetonitrile, followed by liquid–liquid extraction using a 1:1 (v/v) mixture of diethyl ether and dichloromethane as the extracting solvent. Separation of the analytes was achieved through reversed phase high-performance liquid chromatography (HPLC) using a Phenomenex C18 Luna column (4.6 mm×100 mm, 5 µm). A simple isocratic mobile phase consisting of acetonitrile, methanol, and 0.1% formic acid (35:55:10, v/v) was used, operating at a flow rate of 0.5 mL/min. Under these optimized conditions, the LC chromatogram of the spiked standard exhibited distinct peaks at retention times of 2.07 min, 2.59 min, and 4.29 min for Fostemsavir, Maribavir, and the internal standard, respectively. Detection was performed using a triple quadrupole mass spectrometer employing electrospray ionization in positive ion mode and multiple reaction monitoring (MRM) mode. The mass transitions monitored were m/z 377 → 110, m/z 584 → 105, and m/z 420 → 142 for maribavir, fostemsavir, and dolutegravir, respectively. This method provided a rapid analysis within 5 minutes, over a linear concentration range of 15-750 ng/mL for both maribavir and fostemsavir. Method validation was conducted following FDA guidelines for bio-analytical methods, and the results consistently fell within the acceptable limits for both analytes. Therefore, our developed method holds promise for the accurate analysis of maribavir and fostemsavir in human plasma, and it has potential applications in pharmacokinetic studies

Comprehensive analysis of the effects of alternative fuels on diesel engine performance combustion and exhaust emissions: Role of biodiesel, diethyl ether, and EGR

The use of petroleum-based fuels in vehicles poses environmental pollution concerns as well as the need to shift towards alternative fuels due to the diminishing availability of petroleum-based fuels in the future. Therefore, biodiesel fuel stands out among the alternative fuels that could be used in diesel engines. However, when biodiesel fuels are used as fuel in engines, the emission values released from the exhaust do not comply with EURO standards. For this purpose, additional measures to prevent emissions must be taken in addition to alternative fuel usage. In this study, two different methods were simultaneously employed to achieve both the use of alternative fuels and compliance with EURO standards in diesel engines. In the first stage of the study, different proportions of diethyl ether were added to biodiesel fuel. In the study's second stage, a 10% EGR application was performed on the intake manifold to achieve EURO standard-level NO emissions from the exhaust. The biodiesel used in the study was obtained from corn oil through transesterification. Diethyl ether was added to biodiesel at 2.5%, 5%, and 7.5% proportions. As a result of the study, improvements were achieved in effective power and efficiency with the addition of biodiesel and diethyl ether, while NO emissions increased compared to standard diesel fuel. Based on the experimental results, the best combination in terms of both performance and NO emissions was achieved with a 5% diethyl ether-biodiesel blend with a 10% EGR application. While both the biodiesel-diethyl ether mixture and EGR application resulted in a 3% decrease in engine torque, NO emissions decreased by up to 70% compared to diesel fuel.

Co-aromatization of light alkanes over Mo/ZSM-5: How the presences of CH4 and C2H6 & C3H8 influence the aromatization of each other

The chemical inertness of methane is a significant bottleneck for its direct conversion into value-added light aromatics. However, co-feeding higher hydrocarbons with methane produces intermediates that facilitate the participation of methane in aromatization. This synergistic effect has typically been observed under conditions that do not allow the conversion of methane without any co-reactants (over non-Mo-based catalysts at temperatures below 650 ℃). Therefore, the interaction between methane and higher hydrocarbons remains unexplored under conditions that allow methane activation. In this study, we explored the behavior of co-reactants in the direct aromatization of simulated shale gas (a mixture of methane, ethane, and propane) over Mo/ZSM-5. Our aim was to comprehend the complex co-aromatization system under conditions optimized for rigorous activation of methane, which leads to a considerable production of aromatics. The majority of reaction indices in the shale gas aromatization system were governed by the presence of ethane and propane, which were represented by a rapid catalytic lifetime cycle. Mathematical calculations, based on experimentally derived C and H balances, revealed an unexpected anti-synergy within the components of shale gas where the conversion of methane to aromatics was partially suppressed by the presence of ethane and propane. These findings expand the understanding of the complex yet desirable shale gas aromatization system, and also highlight the need for the development of new catalysts capable of further enhancing the activity of methane among the reactants.

Methyl and Ethyl Ethers of Glycerol as Potential Green Low-Melting Technical Fluids.

The study is dedicated to the consideration of lower alkyl ethers of glycerol as potential components of low-melting technical fluids (e.g., heat transfer fluids, hydraulic fluids, aircraft de-icing fluids, etc.). Four isomeric mixtures of glycerol ethers (GMME-monomethyl; GDME-dimethyl; GMEE-monoethyl; GDEE-diethyl) were synthesized from epichlorohydrin and methanol/ethanol in the presence of sodium and subjected to detailed characterization as pure compounds and as aqueous solutions (30-90 vol%). The temperature and concentration dependencies of density, viscosity, cloud point, boiling range, specific heat capacity, thermal conductivity, and rubber swelling were obtained. On the basis of the data obtained, a comparison was made between the aqueous solutions of glycerol ethers and of other common bases for low-melting liquids (glycerol, ethylene glycol, and propylene glycol). Pure glycerol ethers could potentially be used as technical fluids in a very wide temperature range-from -114 to 150 °C. It was further demonstrated that in low temperature applications (e.g., in low-temperature chiller systems) the glycerol-ether-based aqueous heat transfer fluids could provide enhanced efficiency when compared to the glycerol- or propylene-glycol-based ones due to their lower viscosities and favorable environmental properties.

Performance analysis of a hyper-compressor for vinyl acetate and ethylene mixture using real-fluid properties

The ethylene and vinyl acetate (VA) mixture must be compressed to a high pressure of over 100 MPa in a hyper-compressor system to initiate the polymerization. This paper presents a numerical and experimental investigation into the effects of VA concentration on the performance of a hyper-compressor. To this end, an equation of state in the form of Helmholtz free energy was developed to calculate the real thermodynamic properties of VA–ethylene mixture. The average absolute deviations of density and compressibility factor for VA-ethylene compared with experimental values were 1.82% and 1.46%, respectively. Additionally, a three-dimensional (3D) computational fluid dynamics (CFD) model was constructed considering real-fluid thermodynamics, incorporating the motion of the central valve and upstream and downstream pressure pulsations. The predicted [Formula: see text] diagram and pressure pulsation were compared with experimental data to validate the accuracy of the 3D-CFD model. The results demonstrated that a higher VA weight fraction results in a shorter expansion and compression phase; higher indicated power, suction, and discharge losses; and greater pressure fluctuation. The increment of power loss during the discharge process accounted for 73.27% of the indicated power growth 35.96 kW as the VA weight fraction increased from 0% to 40%. The increment of pressure pulsation in the suction and discharge pipe were mainly attributed to high-frequency pulsations above 10 orders and low-frequency pulsations below 10 orders, respectively.

Biocatalytic, Stereoconvergent Alkylation of (Z/E)-Trisubstituted Silyl Enol Ethers.

Alkene functionalization has garnered significant attention due to the versatile reactivity of C=C bonds. A major challenge is the selective conversion of isomeric alkenes into chiral products. Researchers have devised various biocatalytic strategies to transform isomeric alkenes into stereopure compounds; while selective, the enzymes often specifically convert one alkene isomer, thereby diminishing overall yield. To increase the overall yield, scientists have introduced additional driving forces to interconvert alkene isomers. This improves the yield of biocatalytic alkene functionalization at the cost of increased energy consumption and chemical waste. Developing a stereoconvergent enzyme for alkene functionalization offers an ideal solution, although such catalysts are rarely reported. Here we present engineered hemoproteins derived from a bacterial cytochrome P450 that efficiently catalyze the stereoconvergent α-carbonyl alkylation of isomeric silyl enol ethers, producing stereopure products. Through screening and directed evolution, we generated P450BM3 variant SCA-G2, which catalyzes stereoconvergent carbene transfer in E. coli, with high efficiency and stereoselectivity toward various Z/E mixtures of silyl enol ethers. In contrast to established stereospecific transformations that leave one isomer unreacted, SCA-G2 converts both isomers to a stereopure product. This biocatalytic approach simplifies the synthesis of chiral α-branched ketones by eliminating the need for stoichiometric chiral auxiliaries, strongly basic alkali-metal enolates, and harsh conditions, delivering products with high efficiency and excellent chemo- and stereoselectivities.

Emodin-8-O-Glucoside-Isolation and the Screening of the Anticancer Potential against the Nervous System Tumors.

Emodin-8-O-glucoside (E-8-O-G) is a glycosylated derivative of emodin that exhibits numerous biological activities, including immunomodulatory, anti-inflammatory, antioxidant, hepatoprotective, or anticancer activities. However, there are no reports on the activity of E-8-O-G against cancers of the nervous system. Therefore, the aim of the study was to investigate the antiproliferative and cytotoxic effect of E-8-O-G in the SK-N-AS neuroblastoma, T98G human glioblastoma, and C6 mouse glioblastoma cancer cells. As a source of E-8-O-G the methanolic extract from the aerial parts of Reynoutria japonica Houtt. (Polygonaceae) was used. Thanks to the application of centrifugal partition chromatography (CPC) operated in the descending mode using a mixture of petroleum ether:ethyl acetate:methanol:water (4:5:4:5 v/v/v/v) and a subsequent purification with preparative HPLC, E-8-O-G was obtained in high purity in a sufficient quantity for the bioactivity tests. Assessment of the cancer cell viability and proliferation were performed with the MTT (3-(bromide 4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium), CTG (CellTiter-Glo®) and BrdU (5-bromo-2'-deoxyuridine) assays, respectively. E-8-O-G inhibits the viability and proliferation of SK-N-AS neuroblastoma, T98G human glioblastoma multiforme, and C6 mouse glioblastoma cells dose-dependently. E-8-O-G seems to be a promising natural antitumor compound in the therapy of nervous system tumors.

Characterization of soot emitted from the atmospheric combustion of diethyl ether-diesel blends

In accordance with the European commission’s renewable energy proposal for 2030, advanced biofuels should be blended at a minimum of 3.6 % with conventional fuels used for powering internal combustion engines. Ethers, which may be produced using modern production methods from sustainable sources like biomass, may be crucial in this regard in the future. This study demonstrates the impact of diethyl ether as a blend component (mixed with diesel) on the characteristics of the soot generated from the diethyl ether-atmospheric diesel's combustion. The soot used in this work came from a smoke point lamp that burned a mixture of diesel and diethyl ether as per ASTM D1322 standard. Diethyl ether (DEE) and diesel (D) were combined in the following blends: DEE5D (5 % diethyl ether and 95 % diesel v/v), and DEE20D (20 % diethyl ether and 80 % diesel v/v). The obtained soot was characterized in detail using the following: elemental analyzer, X-Ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), RAMAN spectroscopy, thermogravimetric analysis (TGA), and proton nuclear magnetic resonance (1H NMR) spectroscopy. According to the results from XRD and Raman spectroscopy, the soot nanostructure is influenced by the amount of diethyl ether present in the mixture, which raises the reactivity. The results of the elemental analyzer and 1H NMR matched those of the TGA's soot reactivity (oxidations). The results from the SEM and TEM tests, however, were not enoughto support the experimental findings.

Kilogram-Scale Fabrication of a Robust Olefin-Linked Covalent Organic Framework for Separating Ethylene from a Ternary C2 Hydrocarbon Mixture.

One-step adsorptive purification of ethylene (C2H4) from a ternary mixture of acetylene (C2H2), C2H4, and ethane (C2H6) by a single material is of great importance but challenging in the petrochemical industry. Herein, a chemically robust olefin-linked covalent organic framework (COF), NKCOF-62, is designed and synthesized by a melt polymerization method employing tetramethylpyrazine and terephthalaldehyde as cheap monomers. This method avoids most of the disadvantages of classical solvothermal methods, which enable the cost-effective kilogram fabrication of olefin-linked COFs in one pot. Furthermore, NKCOF-62 shows remarkably selective adsorption of C2H2 and C2H6 over C2H4 thanks to its unique pore environments and suitable pore size. Breakthrough experiments demonstrate that polymer-grade C2H4 can be directly obtained from C2H2/C2H6/C2H4 (1/1/1) ternary mixtures through a single separation process. Notably, NKCOF-62 is the first demonstration of the potential to use COFs for C2H2/C2H6/C2H4 separation, which provides a blueprint for the design and construction of robust COFs for industrial gas separations.

Enhancing liquid phase microextraction enrichment in microchip devices under semi-stagnant conditions

Liquid-phase microextraction (LPME) in microfluidic devices involves extraction of acids or bases by diffusion in a pH gradient, from aqueous sample, through a supported liquid membrane (SLM), and into aqueous acceptor phase. The SLM is an integrated part of the device, and separates the donor (sample) and acceptor phase channels. In this work, the geometry of the donor and acceptor phase channels were studied and optimized. With optimal channel geometry (12 mm length, 2 mm width, 0.12 mm depth), metoprolol, haloperidol, nortriptyline, and loperamide were extracted from 900 μL urine and into 25 μL stagnant 10 mM HCl using a mixture of dihexyl ether and tributyl phosphate 1:1 v/v as the SLM. During 30 min of extraction, where the sample was pumped into the system at 30 μL min−1 and the acceptor phase was stagnant, recoveries exceeded 75 % and enrichment factors up to 28 were obtained. Evaluation of the analytical performance supported the reliability of the device in combination with HPLC-UV detection. Implementation of LPME in microfluidic devices is expected to increase in the future and the current paper provides experimental support for the importance of the careful design of the donor and acceptor channels.

Numerical and experimental investigations on the particle formation in oxymethylene ethers (OME[formula omitted], n = 2−4)/ethylene premixed flames

Alternative synthetic fuels can be produced by renewable energy sources and represent a potential route for solving long-term energy storage. Among them, oxygenated fuels have the advantage of significantly reducing pollutant emissions and can therefore be used as carbon-neutral substitute fuels for transportation. In this work, the sooting propensity of different oxymethylene ethers (OMEs) is investigated using a combined experimental and numerical study on a series of burner-stabilized premixed flames under mild to severe sooting conditions. Herein, mixtures of ethylene in combination with the three individual oxymethylene ether (OMEn) for n=2,3,4 are compared in terms of soot formation behavior with pure ethylene flames. The kinetic mechanism from Sun et al. (Proc. Combust. Inst. 36 (2017) 1269–1278) for OMEn combustion with n=1,2,3 is extended to include OME4 decomposition and combustion kinetics. It is combined with a detailed quadvariate soot model, which uses the Conditional Quadrature Method of Moments (CQMOM), and the soot simulation results are validated with Laser-Induced Fluorescence (LIF) and Laser-Induced Incandescence (LII) measurements. It is observed that the three investigated OMEn with n=2,3,4 show similar sooting behavior, mainly reducing larger aggregates while not significantly affecting the formation of smaller particles. Furthermore, the extent of soot reduction is comparable among the three OMEn. The trends and overall reduction are captured very well by the model. The modeling results are analyzed through reaction pathway analyses and sensitivity studies that show the importance of OMEn decomposition and the formation of formaldehyde (CH2O) under rich conditions for reducing species relevant for soot precursor formation. These findings are based on the negligible differences in soot formation between the different OMEn fuels observed in this study.

Some experimental and theoretical studies of diethylene glycol diethyl ether and 2-alkanol mixtures

Experimental density and dynamic viscosity data for the diethylene glycol diethyl ether +2-alkanol (C3 to C6) mixtures have been published at 293.15 K, 303.15 K, 313.15 K, and 323.15 K and at pressure of 0.1 MPa. Excess molar volume and deviation in dynamic viscosity were obtained from experimental data and correlated with Redlich–Kister equation, from the values obtained, the interaction forces were studied. Perturbed chain-statistical associating fluid theory equation of state was used for modeling the density for pure fluids and mixtures. Free volume theory coupled to Perturbed chain-statistical associating fluid theory equation of state was used to modeling the viscosity of pure fluids and mixtures; in the case of binary mixtures, we proposed a simple mixing rule and used the Pourabadeh et al. mixing rule. Good results in the prediction and correlation of experimental liquid density and dynamic viscosity for binary mixtures were obtained, 0.12% and 2.28%, respectively.