Ether Type Research Articles

Comparative Phytochemistry of Polyacetylenes of the Genus Artemisia (Asteraceae): Compounds with High Biological Activities and Chemotaxonomic Significance

In spite of the many chemical reports on polyacetylenes of the genus Artemisia, combined conclusions regarding their distribution and biological functions are widely missing. The aim of the present review was to arrange the diversity of polyacetylenes in the genus following biogenetic aspects and group them together into characteristic structural types. The co-occurrence of the dehydrofalcarinol type with the aromatic capillen-isocoumarin type represents a characteristic biogenetic trend, clearly segregating species of the subgenus Dracunculus from those of the subgenera Artemisia and Absinthium, distinguished by the spiroketal enol ether and/or linear triyne type. Various accumulation trends toward specific structures additionally contribute to a more natural species grouping within the subgenera. Biological activities were reported for all four structural types, ranging from antifungal, insecticidal, nematicidal, and cytotoxic properties to allelopathic effects. Of particular interest were their remarkable cytotoxic potencies, from which the very high values of dehydrofalcarin-3,8-diol may be associated with the pronounced affinity of this type to form extremely stable bonds to proteins acting in signaling pathways. The aromatic acetylene capillin inhibited the viability of various tumor cells in a dose- and time-dependent manner. Its potent apoptosis-inducing activity was induced via the mitochondrial pathway. A group of spiroketal enol ethers was identified as inhibitors of PMA-induced superoxide generation. Among them, the epoxide of the isovalerate ester exhibited the highest potency. The ecological impact of acetylene formation was made apparent by the allelopathic effects of DME of the linear triyne type, and the aromatic capillen by inhibiting seed germination and growth of widespread weeds.

UNUSUAL TRANSFORMATIONS OF 2,3- AND 1,3- BUTHANEDIOL MONOPROPARGYL ETHERS

Research in the field of chemistry of oxygen-containing derivatives of acetylene has acquired considerable interest. Of the simple ethers containing a triple carbon-carbon bond, ethynyl and propargyl ethers of monohydric alcohols and phenols, as well as alkyl and aryl ethers of acetylene glycols have been studied in most detail. Alkynyl, especially propargyl mono- and diesters of polyhydric alcohols have not been studied extensively. Due to the presence of highly reactive centers, ethers occupy a special place in the field of chemistry of oxygen-containing derivatives of acetylenes. Acetylene ethers of glycols usually form ketoxy esters under conditions of acid-catalytic hydration. Using the tendency of propargyl compounds to prototropy in a basic medium, we studied under these conditions the possibility of converting monopropargyl ethers of 2,3- and 1,3-butanediols into oxygen-containing heterocycles. The available data indicate that these types of triple-bonded ethers are of great interest, both theoretically and practically. Among acetylenic ethers of polyhydric alcohols, which are the most interesting class of oxygen-containing alkynes in terms of synthesis and practice, propargyl ethers of acyclic glycols have been studied. In this regard, we have undertaken an experimental study of the synthesis routes of mono- and dipropargyl ethers of glycols and their unusual transformations. Acetylene ethers have proven themselves to be very valuable substances used in various fields of organic synthesis and exhibiting interesting properties of applied nature. Propargyl mono- and diesters of polyhydric alcohols with a triple bond are of great interest, both theoretically and practically. The paper presents the results of a study of acid-catalytic intramolecular cyclohydration and the synthesis of heterocyclic compounds based on propargyl ethers of glycols. The latter were monopropargyl ethers of 2,3- and 1,3-butanediols (I, II). The structure of the obtained heterocyclic compounds was confirmed by NMR and IR absorption spectra. Keywords: cyclohydration, monopropargyl ethers, heterocyclization, butanediols, spectrum, dioxane, t-BuO, NaOH.

Silyl ether-modified polyalkylene glycols with high viscosity index

Abstract To improve the viscosity index (VI) of polyalkylene glycol (PAG), the hydroxyl group was modified into a silyl ether. The hydrogen bond of the unmodified PAG was broken and its kinematic viscosity at 40 oC (KV40) was substantially reduced. The kinematic viscosity of the modified PAG at 100 oC (KV100) showed a slight reduction, compared with the unmodified one, demonstrating that the VI could be greatly improved. The VIs of polypropylene glycol (PPG), which contains two hydroxy groups, (Mn = 1,120) and its trimethylsilyl ether (PPG-TMS), were 146 and 299, respectively. A similar improvement in VI was observed in PAG with different molecular weights and with different types of silyl ethers.

Evaluation of Phase Transition Behavior of Nonionic Surfactant Solutions Containing Electrolytes by Rheo-Impedance Measurement

Aqueous nonionic surfactant solutions are known to undergo a phase transition from lamellar to vesicle when shear force is applied. It is also known that viscosity increases with the phase transition1). Our group has previously reported that the impedance decreases during the phase transition2). However, there are still many unknown aspects of the conduction mechanism in aqueous surfactant solutions of before, after, and during the phase transition. Therefore, in this study, we performed rheo-impedance measurements of aqueous surfactant solutions with different electrolyte concentrations. Furthermore, the dependency of the phase on the rheological parameters was verified using small-angle light scattering.As surfactant, two types of polyoxyethylene lauryl ethers (BL4.2 and BL4SY) were used. As electrolyte, an aqueous Na2SO4 solution of 1.0 × 100 mol/L, 1.0 × 10-1 mol/L, 1.0 × 10-2 mol/L or 1.0 × 10-3 mol/L was prepared. The sample solution was a mixture of Na2SO4 solution, surfactant, and pure water with ratios of 5 wt%, 40 wt%, and 55 wt%, respectively. The sample solution was heated to 40°C, stirred, and allowed to settle until all bubbles disappeared completely. Samples without electrolyte (40 wt% surfactant, 60 wt% pure water) were prepared correspondingly. Rheology was measured with a gap of 1.0 mm over 30 min, at 35 °C, and a shear rate of 10 s-1. Simultaneously, electrochemical impedance was measured continuously with an initial potential of 0 V, in the frequency range of 500 kHz to 1 kHz (5 points per decade), with an amplitude 10 mV using a potentiogalvanostat with FRA (Hz-7000).Phase transitions were observed in all solutions. Electrolyte concentration did not affect the time to phase transition. Capacitive semicircles were observed in all solutions. Curve fitting showed that the resistance of the solutions decreased after the phase transition. This is thought to be due to the difference in the orientation of the structure, which allows for easier transfer of protons and sodium ions in the vesicle than in the lamellar. When the electrolyte concentration was low, the resistance was greater than that of the solution without electrolyte. On the other hand, when the electrolyte concentration was high, the resistance decreased obviously. We are currently investigating the cause of this phenomenon. Details will be reported on the day.1) Diat, D. Roux, F. Nallet, J. Phys. II France, 3, 1427 (1993).2) Isao Shitanda et al., Proceedings of the 90th Annual Meeting of the Electrochemical Society of Japan (2023).

Facile Synthesis and Antitumor Activity of o-Iodoaromatic Ether

Abstract: In this study, an efficient method for the synthesis of one type of aromatic ether was introduced, and its antitumor activity was investigated. Specifically, (diacetoxyiodo)arene was prepared from 2-methyliodobenzene and used to oxidize the 4-nitrophenol to give the aromatic ether. Our study further found that aromatic ether has a strong apoptotic effect on U937 monocytes, suggesting that it might be developed as a new drug for the treatment of acute myeloid leukemia.

Itaconic anhydride functionalized cyanoethyl cellulose with crosslinked structure enabled improved dielectric properties

AbstractAs a type of cellulose ether, cyanoethyl cellulose (CEC) is considered to be a promising candidate for polymer dielectrics due to its sustainable nature and high dielectric constant induced by the cyano groups. However, the relatively high conduction loss of CEC arising from the charge motion across the polymer degrades its dielectric properties. In this work, we designed and synthesized an all‐organic polymer composite of CEC/itaconic anhydride (ITA) to improve dielectric properties. The CEC matrix was graft functionalized by ITA via an esterification reaction between the anhydride groups of ITA and hydroxyl groups of CEC. Meanwhile, crosslinking structure was also established in the composite by the generation of diester. Significantly improved dielectric constant (εr), elevated breakdown strength (Eb), restrained dielectric loss (tan δ) and decreased conductivity (σ) were observed in the composites compared with unmodified CEC. The εr increased from 17 for pure CEC to 32 for CEC/ITA at 1 kHz, and Eb also soared from 145 MV m−1 for CEC to 226 MV m−1 for the composite. The tan δ reduced from 0.24 for pure CEC to about 0.05 for the composite at 100 Hz. This should be attributed to the molecule trapping centers arising from the high electron affinity ITA and the formation of crosslinked networks as well as hydrogen bonding, which impeded the electric conduction. It also provided additional advantages of better dielectric properties for the CEC/ITA composites than pure CEC at high temperatures, which may offer inspiration for the design and preparation of bio‐based dielectrics for high temperatures. © 2024 Society of Chemical Industry.

Polyoxometalatocrown ether: A new type of metallacrown ether based on polyoxometalate

Polyoxometalatocrown ether: A new type of metallacrown ether based on polyoxometalate

A novel glycidyl ether type tetrafunctional epoxy resin: synthesis, cure kinetic and properties

Thermal stable epoxy is indispensable for aerospace and advanced electronic application. As replacements for common thermal stable epoxy TGDDM, we previously developed several glycidyl ether type tetrafunctional epoxies. As a continuous effort to achieve higher Tg , a novel tetrafunctional epoxy with shorter spacer and lower epoxide equivalent weight (TFEP) was synthesized. TFEP was mixed with DGEBA, and cured with MHHPA and DDS, respectively. TFEP increases the Tg and char residues, and reduces the maximum weight loss rate. Tg of 30 wt%TFEP/DGEBA/DDS is higher than that of previously reported epoxies, whereas Tg of 40 wt%TFEP/DGEBA/DDS is comparable to that of TGDDM/DDS. The influences of TFEP on the Td , strength, toughness, water absorption and free volume are different, depending on the curing agents. Moreover, 30 wt%TFEP/DGEBA/DDS exhibits higher toughness and Td5% , lower water absorption, and comparable strength, compared with TGDDM/DDS, providing a better replacement for TGDDM. Besides, TFEP slightly increases the Ea .

Structural modification of C2-substituents on 1,4-bis(arylsulfonamido)benzene or naphthalene-N,N′-diacetic acid derivatives as potent inhibitors of the Keap1-Nrf2 protein-protein interaction

The Keap1-Nrf2-ARE signaling pathway is an attractive therapeutic target for the prevention and treatment of oxidative stress-associated diseases by activating the cellular expression of cytoprotective enzymes and proteins. Small molecule inhibitors can directly disrupt the Keap1-Nrf2 protein-protein interaction (PPI), resulting in elevated levels of Nrf2 protein and subsequent stimulation of related antioxidant responses. Previously, we found that 1,4-bis(arylsulfonamido)benzene or naphthalene-N,N′-diacetic acid derivatives with an ether type C2-substituent on the benzene or naphthalene core exhibited potent inhibitory activities with IC50's in the submicromolar or nanomolar range. We here describe a more detailed structure-activity relationship study around the C2 substituents containing various polar linkers shedding new insight on their binding interactions with the Keap1 Kelch domain. The key observation from our findings is that the substituents at the C2-position of the benzene or naphthalene scaffold impact their inhibitory potencies in biochemical assays as well as activities in cell culture. The biochemical FP and TR-FRET assays revealed that the naphthalene derivatives 17b and 18 with an additional carboxylate at the C2 were the most active inhibitors against Keap1-Nrf2 PPI. In the cell-based assay, the two compounds were shown to be potent Nrf2 activators of the transcription of the Nrf2-dependent genes, such as HMOX2, GSTM3, and NQO1.

Linear and nonlinear viscoelasticity of edible o/w emulsions used as saturated fat replacers

A recent strategy for controlling saturated fat intake consists on the design of vegetable oil-based emulsions. The aim was to characterize the linear and nonlinear viscoelastic properties of o/w emulsions formulated with two types of cellulose: MX (methylcellulose, MC) and F4M (hydroxypropyl methylcellulose, HPMC). The emulsions were characterized by steady flow curves and frequency sweeps in SAOS (Small Amplitude Oscillatory Shear) regime. In order to evaluate linear and non-linear response, strain sweeps were performed from 0.01 to 1000% strain amplitude at different frequencies (0.1, 1 and 5 Hz). Fourier Transform rheology and orthogonal stress decomposition were applied and LAOS (Large Amplitude Oscillatory Shear) parameters (G’M, G’L, ηM’, ηL’, S and T) were analysed. The type of cellulose ether significantly affected both flow behaviour and internal structure of the samples. MX emulsion presented greater consistency at rest and higher gel strength in SAOS regime with a lower frequency dependence than F4M emulsion. However, both emulsions presented similar properties at large deformations, showing shear thinning and strain stiffening behaviour. Nonlinear viscoelastic analysis allows to improve the textural characterization of emulsions, providing complementary useful information for establishing the most suitable formulation in experimental conditions closer to real applications and processes.

Investigating the efficiency of bisphenol-A diglycidyl ether/resole phenol formaldehyde/polyamine blends as Cerium adsorbent from aqueous solution

The blending process of epoxy resin types of bisphenol-A diglycidyl ether (DGEBPA) with resole phenol-formaldehyde (RPF) and polyamine (PA) materials is investigated for Cerium (Ce+3) desorption. Two different blend weight ratios of EPR2 (DGEBPA/PA/RPF; 2:1:1) and EPR3 (DGEBPA/PA/RPF; 2:1:3) are used for the evaluation and compared with the epoxy blank sample EPR1 (DGEBPA/PA; 2:1), under the same preparation conditions of the thermal curing reaction for 1 h at 80 °C. SEM/EDX, XRF, and FTIR are used to illustrate the obtained sorbents. Since cerium is utilized in many industries, this research examines the prospect of extracting it from aqueous solutions that include it using sorbent materials that are affordable, simple to use, and easy to apply. Balance equilibrium is determined by; 40 ppm, solid-to-liquid ratio: 0.1:10 g/mL, room temperature, time: 4 h, and pH 4. Cerium is extracted almost completely without significant solution changes in the chemical composition. Sorption isotherm models are used to analyze the investigative findings. Kinetic, isotherms, and thermodynamics analysis for the obtained data have been performed followed by Langmuir models and pseudo-second-order. The adsorption capacity of Cerium is obtained near; 1.8, 3.9, and 11.7 mg/g for EPR1, EPR2, and EPR3, respectively. The detected results of Ce+3 adsorption; EPR3 is the most effective Cerium adsorbent from solutions and for application on real samples from Nuclear Materials Authority.

Poly(dibenzofuran-p-terphenyl piperidinium)-based anion exchange membranes with enhanced phase separation for water electrolysis

Anion exchange membranes (AEMs) based on non-aryl ether–type poly(aryl piperidinium) have recently drawn significant attention because of their excellent ion exchange capacity (IEC), chemical stability, and ionic conductivity. However, the reactivity of poly(aryl piperidinium) varies significantly depending on the type of monomer used and is also accompanied by very rapid polymerization. These limitations have hindered the development of an AEM with controllable morphology. In the present study, AEMs with the desired morphology were obtained using hydrophilic and hydrophobic monomers; indeed, a well-controlled morphology was achieved even though they were random copolymers. Specifically, hydrophilic dibenzofuran and hydrophobic p-terphenyl were used as raw materials to develop the novel AEM material p(BF-TP)-Pip-x, i.e., a poly(dibenzofuran-p-terphenyl-piperidinium)-based copolymer. The dibenzofuran content relative to p-terphenyl was 5%, 10%, and 30%, resulting in three types of p(BF-TP)-Pip-x-based membranes. Their properties were compared with a poly(p-terphenyl-piperidinium)(pTP-Pip)-based AEM, a homopolymer composed solely of p-terphenyl. p(BF-TP)-Pip-10, a membrane with a dibenzofuran content of 10%, exhibited excellent mechanical properties with a tensile strength of 42 MPa and an elongation of break of 9.7%, along with high ionic conductivity at 144 mS cm−1 at 80 °C, owing to its well-developed, phase-separated morphology. Furthermore, its conductivity retention was 93% after treatment in a 2 M KOH solution at 80 °C for 960 h. For a given IEC, excellent alkaline stability was achieved compared to existing poly(aryl piperidinium)-based AEMs. p(BF-TP)-Pip-10 also exhibited excellent thermal and oxidative stability. In AEM water electrolysis tests, the membrane showed a very high current density of 1309 mA cm−2 at 1.8 V, a 120% improvement over pTP-Pip.

Synthesis, α‐Glucosidase Inhibitory Activity, and Molecular Docking Studies of Tri(benzo)‐5‐azacrownophanes with a γ‐Piperidone Moiety

AbstractMulticomponent reactions (MCR) are power tools in modern organic synthesis. These reactions have many advantages over single component reactions, including saving time and chemicals. Moreover, compounds with complicated structures can be synthesized based on simple substrates and one‐step reactions, without the tedious work of separating intermediate compounds. Taking full advantage of this tool, over the past 10 years we have synthesized novel crown compounds with the successful introduction of different bioactive moieties into molecules. As part of our ongoing research, this study reports on the synthesis of a new type of crown ether based on a three component reaction of an aldehyde, a ketone, and ammonium acetate in dry solvent, at specific temperature. The structure of the new compounds was identified using physical‐chemical methods of analysis including IR, 1H & 13C NMR, HRMS and single‐X ray diffraction. The effects of the newly synthesized azacrown ethers on the enzyme α‐glucosidase were then explored and they were shown to be potential candidates in the search for new antidiabetic drugs. Among five tested compounds, two compounds are active again the enzyme α‐glucosidase and expressed IC50 values of 407.17±9.01 μM and 345.90±6.75 μM. Molecular docking studies were also performed to investigate the binding mode of the synthetic compounds to α‐glucosidase. Finally, ADMET parameters were assessed to investigate the relationship between structure and biological activities.

Highly active artificial potassium channels having record-high K+/Na+ selectivity of 20.1

Replicating extraordinarily high membrane transport selectivity of protein channels in artificial channel is a challenging task. In this work, we demonstrate that a strategic application of steric code-based social self-sorting offers a novel means to enhance ion transport selectivities of artificial ion channels, alongside with boosted ion transport activities. More specifically, two types of mutually compatible sterically bulky groups (benzo-crown ether and tert‑butyl group) were appended onto a monopeptide-based scaffold, which can order the bulky groups onto the same side of a one-dimensionally aligned H-bonded structure. Strong steric repulsions among the same type of bulky groups (either benzo-crown ethers or tert‑butyl groups), which are forced into proximity by H-bonds, favor the formation of hetero-oligomeric ensembles that carry an alternative arrangement of sterically compatible benzo-crown ethers and tert‑butyl groups, rather than homo-oligomeric ensembles containing a single type of either benzo-crown ethers or tert‑butyl groups. Coupled with side chain tuning, this social self-sorting strategy delivers highly active hetero-oligomeric K+-selective ion channel (5F12‧BF12)n, displaying the highest K+/Na+ selectivity of 20.1 among artificial potassium channels and an excellent EC50 value of 0.50 µmol/L (0.62 mol% relative to lipids) in terms of single channel concentration

Synthesis of crown ether-based microporous organic networks: A new type of efficient adsorbents for chlorophenols.

Microporous organic networks (MONs) are a booming class of functional materials in elimination of environmental pollutants. However, the limit varieties of MONs still restrict their broad applications. Here we report the synthesis of a novel type of crown ether (CE)-based MONs via the coupling between brominated 18-crown-6 ether and different aromatic alkynyls. The constructed CE-based MONs integrates the good conjugation property of MONs and the inherent host-guest binding sites of CE, allowing the ultrafast and efficient adsorption and removal of a typical environmental priority pollutant 2,4,6-trichlorophenol (2,4,6-TCP). The hydrophobic CE-based MONs can also address the recovery challenge of unstable discrete CE in most organic and inorganic solvents. All CE-based MONs displayed fast adsorption kinetics (< 3min) and large adsorption capacities (229.1-341.7mgg-1) for 2,4,6-TCP. The CE-based MONs also gave stable adsorption capacities for 2,4,6-TCP in pH range of 4.0-6.0, NaCl concentration of 0-40mgL-1, HA concentration of 0-30mgL-1, or H2O2 ratio of <5%. Density functional theory calculation, Fourier transform infrared and X-ray photoelectron spectra evaluation revealed adsorption process involved hydrophobic, π-π and hydrogen bonding interactions. The CE-based MONs also showed favorable reusability and good adsorption for other toxic chlorophenols. This work highlights the potential of CE-based MONs in contaminants elimination.

Liquid-liquid extraction of calcium in a scaled-out microfluidic device: Process intensification using a crown ether-ionic liquid system

Solvent extraction of calcium was investigated in four microchannels parallelized on a microfluidic chip. Uniform flow distribution of observed flow patterns in parallel microchannels shows successful numbering-up of the microfluidic device. First, flow regime maps were plotted for six liquid-liquid systems. A parallel flow regime with complete phase separation was chosen as the desired flow regime for extracting the calcium ion. Organic phase and crown ether types were tested to obtain the maximum extraction of calcium from the aqueous phase. In these conditions, the effects of crown ether concentration, the concentration of calcium ion and pH were studied in order to optimize the extraction efficiency using the Box-Behnken method. The mass transfer coefficient was also determined as a function of residence time at different concentrations of calcium metal ions. In the second step, ionic liquid-based solvent extraction was studied. In this regard, the performance of the diluent (conventional organic solvent) type on the calcium separation efficiency was investigated. An excellent improvement in separation efficiency (7.1–64.2%) was achieved for the EMIM NTf2/n-butyl acetate mixture compared to butyl acetate. In the final step, continuous multistage liquid-liquid extraction of the calcium ion was performed using three series microchips to evaluate the microfluidic cascade's performance.

Characterization of the oxymethylene ether fuels flame structure for ECN Spray A and Spray D nozzles

Synthetic fuels will play a major role on the reduction of pollutant emissions and carbon footprint of ICE engines. The use of renewable energy and CO2 for its production maps out a promising route to achieve ICE carbon neutrality. Among these fuels, oxymethylene ethers are also interesting for their potential to drastically reduce soot formation. However, a proper characterization of their properties and behaviour is mandatory to reach full implementation in commercial engines. For this reason, this work presents a detailed characterization of the flame structure of two types of oxymethylene ethers (OMEX and OME1) using high-speed chemiluminescence imaging and Planar Laser-Induced Fluorescence (PLIF). Test were performed in a constant-pressure combustion vessel, with the operating conditions and two different injector nozzles from the Engine Combustion Network (Spray A and Spray D). Regions associated with low-temperature chemical reactions are observed thanks to the formaldehyde PLIF while evolution of the high-temperature reactions has been analysed based on hydroxyl excited state (OH*) chemiluminescence and hydroxyl PLIF. On-resonant and off-resonant measurements were performed for OH PLIF with a dye laser in order to remove other radiation sources not linked to OH fluorescence, whilst 355 nm radiation from the third harmonic of a Nd:YAG laser are used to excite CH2O molecules. On the one hand, the results show that the combustion of OME1 with Spray A is characterized by a flame structure very different to that of a diffusion flame. It is characterized by large cool flame region followed by a short high-temperature zone. On the other hand, the combustion of OMEX with both nozzles and OME1 with Spray D show more similarities with a diffusion flame structure. The stoichiometry of the fuel and the equivalence ratio fields achieved strongly affect the structure and latter evolution of the flames.

Synthesis of Hybrid Epoxy Methacrylate Resin Based on Diglycidyl Ethers and Coatings Preparation via Cationic and Free-Radical Photopolymerization

A series of difunctional epoxy methacrylate resins (EAs) containing at least one epoxy and at least one methacrylate group were synthesized by means of an addition reaction between epoxy-terminated diglycidyl ethers and methacrylic acid. In order to investigate the impact of polymer architecture on the course of addition reactions and further coating properties, several different types of diglycidyl ethers, i.e., linear, containing aliphatic or aromatic rings, with a short or polymeric backbone, were employed in the synthesis. The carboxyl-epoxide addition esterification reactions have been found to, in a relatively straightforward manner, control the extent of acrylation depending on the substrate feed ratio and reaction time. The structure of obtained pre-polymers was evaluated by FT-IR and NMR methods. At the same time, the extent of addition reactions was validated via quantitative analysis, including non-volatile matter content (NV), acid value (PAVs), and epoxy equivalent value (EE) analysis. The modification was carried out in a manner likely to create a compound with one epoxy and one carbon-carbon pendant group. Hence, due to the presence of both functionalities, it is possible to crosslink compositions based on synthesized EAs via two distinct mechanisms: (i) cationic polymerization or (ii) free-radical polymerization. Synthesized epoxy methacrylate pre-polymers were further employed for use in formulate photocurable coating compositions by the cationic or radical process. Furthermore, the photopolymerization behavior and properties of cured coatings were explored regarding some structural factors and parameters. The investigated polymeric materials cure in a short time to obtain coatings with good properties, which is why they can be successfully used to produce protective and decorative coatings for many industries.

Effect of Cellulose Ether and Starch Ether on Hydration of Cement Processes and Fresh-State Properties of Cement Mortars.

The production of factory-made mortars is a multicomponent system. Viscosity-modifying admixtures (VMAs) are an inherent ingredient of these materials. The correct choice of the amount and type of these admixtures is important from the practical and scientific points of view. In this article, the use of cellulose ether (CE) and starch ether (SE) in cement pastes and mortars is studied. This research focuses on the hydration process and fresh-state properties of mortars because this subject determines the correct choice of the amount and type of admixture used, and the results determine the application and properties of hardened mortars. Polymers were added in the range from 0.056% to 0.22% in relation to the dry ingredients of the mortar. The research showed that cellulose ether had the greatest impact on the consistency, air content, bulk density, and water retention of ordinary dry-mix mortars. On the other hand, starch ether affected the hydration process, delaying the setting and hardening processes much more than cellulose ether. The action of these admixtures rose with the increase in the amount of polymer used in different ways (depending on the type of ether).

An easy method for reliable valuation of flash point temperature of organic ethers

Organic ethers are volatile and flammable because there are no significant intermolecular forces between their molecules and their uses require safety assessments in industrial processes. They have a wide variety of industrial uses such as primers for gasoline engines, fuel additives, commercial solvents, and rocket propellants but the measurements of the flash point of toxic and hazardous organic ethers are very difficult. This work introduces a simple method for a reliable prediction of the flash point of various types of organic ethers, which can be easily applied for estimation of the flash point of many organic ethers where their experimental values are not available in the literature. Different types of 121 organic ethers are used to derive and test the new correlation by considering the number of the number of carbon, oxygen, nitrogen, and chlorine atoms as well as the contribution of hydroxyl or specific group and lowering flash point fragments. The great consistency of the novel approach is compared with the results of one of the best existing methods where the values of Mean Absolute Percent Error (MAPE) of the new and two comparative models are 2.38, 4.67, and 6.10, respectively.