Hydroxyethyl Group Research Articles

Mussel-Inspired, Self-Healing, Highly Effective Fully Polymeric Fire-Retardant Coatings Enabled by Group Synergy.

Fire-retardant coatings represent a universal cost-effective approach to providing fire protection for various substrates without compromising substrates' bulk properties. However, it has been attractive yet highly challenging to create waterborne polymeric fire-retardant coatings combining high-efficiency, generally strong adhesion, and self-repairability due to a lack of rational design principles. Inspired by mussel's unique adhesive, self-healing, and char-forming mechanisms, herein, a "group synergy" design strategy is proposed to realize the combination of self-healing, strong adhesion, and high efficiency in a fully polymeric fire-retardant coating via multiple synergies between catechol, phosphonic, and hydroxyethyl groups. As-created fire-retardant coating exhibits a rapid room-temperature self-healing ability and strong adhesion to (non)polar substrates due to multiple dynamic non-covalent interactions enabled by these groups. Because these functional groups enable the formation of a robust structurally intact yet slightly expanded char layer upon exposure to flame, a 200µm-thick such coating can make extremely flammable polystyrene foam very difficult to ignite and self-extinguishing, which far outperforms previous strategies. Moreover, this coating can provide universal exceptional fire protection for a variety of substrates from polymer foams, and timber, to fabric and steel. This work presents a promising material design principle to create next-generation sustainable high-performance fire-retardant coatings for general fire protection.

Citric acid crosslinked hydroxyethyl tamarind gum-based hydrogel films: A promising biomaterial for drug delivery

This investigation explored citric acid crosslinked hydroxyethyl tamarind gum hydrogel films as a potential biomaterial for drug delivery. Hydroxyethylation of tamarind gum aimed to improve its solubility, swelling, and crosslinking potential. The synthesized hydroxyethylated tamarind gum (HETG) was comprehensively characterized, revealing the presence of hydroxyethyl groups and increased viscosity in comparison to unmodified tamarind gum. The citric acid crosslinked HETG hydrogel films were developed by esterification-crosslinking mechanism. The films were characterized using instrumental techniques and evaluated for total carboxyl content, mechanical properties, swelling behavior, drug loading, drug release, antibacterial activity, hemocompatibility and in vitro wound healing activity. The presence of ester crosslinks and extent of crosslinking was confirmed through total carboxyl content and instrumental analysis. Varying HETG (2–2.5%w/v) and citric acid (1–1.4 %w/v) concentrations resulted in films with tunable mechanical strength, swelling, and drug loading. The films effectively controlled the release of a water-soluble drug (80.87–99.70 % in 24 h) through a non-Fickian diffusion mechanism. The optimized HETG hydrogel film showed antimicrobial activity, hemocompatibility, and support for cell growth, confirming its biocompatibility and potential for wound healing. Citric acid-crosslinked HETG films appear promising for drug delivery to wounds, meriting further in vivo study.

Tackling Microbial Resistance and Emerging Pathogens with Next-Generation Antibiotics

In the 19th century, the discovery of penicillin revolutionized medicine, saving millions from infectious diseases. People believed that they had won the war against infections. However, the misuse and abuse of antimicrobial agents are accompanied by major ramifications like antimicrobial resistance, creating drug-resistant superbugs. This issue is concerning worldwide, as dwindling effective antibiotics lead to rising healthcare costs, re-hospitalization, and disease severity. Consequently, multiple initiatives have been undertaken to address these phenomena, including the development of antimicrobials with novel modes of action. Without novel discoveries of newer antimicrobial agents, we may face the risk of entering a post-antibiotic era where uncomplicated infections become untreatable. Ultimately, the morbidity and mortality rate would rise higher than in the pre-antibiotic era. This study highlights the recent developments in antimicrobials over the past five years and explores the strategies employed by the new generation of drugs to act against resistance. For example, we discuss the treatment of Carbapenem-resistant Enterobacteriaceae, such as Klebsiella pneumoniae Carbapenamase-producing Gram-negative bacteria, by using meropenem-vaborbactam. Plazomicin, lacking a hydroxyl group, effectively combats metallo-beta-lactamase, which meropenem-vaborbactam is unable to address. It is also preferred over tobramycin and gentamicin due to its hydroxyethyl group. Furthermore, we explore the conjugation of nanoparticles with antibiotics, which demonstrated synergistic effects and positive outcomes on different bacterial resistance. Mechanisms include increased drug adhesion to bacterial cell walls, generating oxidative stress, and causing mistranslation by detaching ribosomes from tRNA. Additionally, the IspH inhibitors like 4’-flurouridine targeting the MEP pathway which is also included in the discussion. This report thoroughly examines newer generations and classes of antibiotics, highlighting the improvements made by scientists to combat bacterial resistance effectively.

Flotation collector lauryldiethanolamine: Adsorption configuration impact on collecting efficiency

In the reverse flotation separation of apatite and its associated siliceous gangue minerals, the common collector dodecylamine (DDA) exhibits a poor selectivity. To remedy this issue, this study implements a change to DDA molecular structure by integrating two 2-hydroxyethyl groups at the N atom position, ultimately producing a freshly developed collector, lauryldiethanolamine (LDEA). Micro-flotation experiments reveal that, relative to DDA, LDEA showcases an enhanced selectivity in separating apatite from its associated siliceous gangue minerals quartz and K-feldspar through reverse flotation. This difference primarily stems from the weaker collecting ability of LDEA for apatite particles relative to DDA. Nevertheless, zeta potential measurements and X-ray photoelectron spectroscopic tests consistently show that, under identical dosage conditions, LDEA and DDA exhibit similar adsorption quantities on apatite surfaces. This observation implies that factors beyond its adsorption quantities inevitably influence the collecting ability of LDEA for apatite particles. First-principles calculations unveil markedly different adsorption configurations of LDEA and DDA on apatite surfaces, suggesting that the difference in the adsorption configurations of LDEA and DDA accounts for the significant variance in their collecting abilities for apatite particles.

Impact of hydroxyethyl headgroup on long-chain quaternary ammonium cationic surfactants: Solubility, surface activities, self-assembly behaviors, and rheological properties

The incorporation of hydroxy groups into long-chain quaternary ammonium surfactants can enhance their solubility and confer other desirable properties; however, the systematic investigation on the solution properties and the influence of molecular structures was less documented. In this work, two saturated C18-tailed quaternary ammonium surfactants with dual hydroxyethyl moieties, namely N,N-bis(2-hydroxyethyl)-N-methyloctadecan-1-aminium iodide (HEOAI) and N,N-bis(2-hydroxypropyl)-N-methyloctadecan-1-aminium iodide (HPOAI), were designed and synthesized. We investigated and compared their Krafft temperature (Tk), surface activities, self-assembly behaviors, and rheological properties. Our findings demonstrate that the introduction of hydroxyethyl groups dramatically improves the solubility and surface activities. The Tk of HEOAI and HPOAI is approximately 50 °C lower than that of the corresponding surfactant octadecyl trimethylammonium iodide. Both surfactants exhibit lower critical micelle concentration and equilibrium surface tension compared to those of corresponding conventional quaternary ammonium surfactant. This should be ascribed to the formation of hydrogen bonds between hydroxyl groups and water molecules. Moreover, HPOAI shows even better solubility and surface activities than HEOAI does. Additionally, the presence of two more methyl groups for HPOAI enhances its ability to form worm-like micelles in pure water. However, HEOAI shows better salt and temperature resistance for maintaining stability of worm-like micelles. A solution containing 50 mM HEOAI with 10 % NaCl exhibits temperature tolerance up to around 80 °C, indicating potential application as fracturing fluid for shallow and medium oil/gas reservoirs. These findings contribute to designing surfactants with improved solubility and diverse properties.

Effect of the presence of trace sulfur dioxide on piperazine-based amine absorbents for carbon dioxide capture

The effect of the presence of trace SO2 in industrial flue gas on the amine-scrubbing-based absorption process for CO2 capture has been a matter of concern. This study aimed to investigate the effect of trace SO2 on the CO2 capture process using piperazine-based amine absorbents, focusing on SO2 resistance capability, SO2/CO2 absorption selectivity, and cyclic stability. The presence of trace SO2 not only restrains CO2 absorption, but also promotes the formation of carbamate within the piperazine-based amine absorbents. Remarkably, the incorporation of aminoethyl group in piperazine-based amine absorbents can enhance the SO2 resistance capability by promoting the formation of carbamate, while piperazine-based amine absorbents with hydroxyethyl group can promote the formation of bicarbonate to reduce the SO2 resistance capability. The work offers valuable insights into the efficient application of novel amine absorbents for CO2 capture from practical industrial flue gas.

Effect of novel surfactant protic ethanolamine based ionic liquids on the aqueous solubility and thermodynamic properties of acetaminophen

The solubility of poorly soluble drugs in aqueous media remains an obstacle in the pharmaceutical development process. Ionic liquids (ILs), with their remarkable solvent properties, have gained considerable attention as potential solubility enhancers for such drugs. In this context, surfactant protic ethanolamine-based ILs have emerged as a particularly promising class of compounds due to their unique dual functionality. This study explores the significant role of these novel solvents in improving drug solubility, focusing on their potential applications in pharmaceutical formulations. Acetaminophen (ACP), a widely used analgesic and antipyretic drug, often encounters solubility limitations that hinder its effective pharmaceutical applications. In the past few years, there has been a growing recognition of the potential of ILs (ionic liquids) as effective solvents. They offer promising prospects for enhancing the solubility of pharmaceutical substances in water-based solutions. This study investigates the enhancement of ACP solubility through the utilization of ILs. The solubilization behavior of ACP in the attendance of mono, bis and tris-(2-hydroxyethylammonium) octanoate systems is explored, highlighting the significant impact of different number of hydroxyethyl groups combinations on its solubility profile. Experimental results reveal that these ILs exhibit a remarkable ability to improve the solubility of ACP, making them attractive candidates for pharmaceutical formulations. The mechanisms underlying this enhancement are discussed, encompassing factors such as the ion-specific interactions, polarity, and hydrogen bonding capabilities of ionic liquids. Furthermore, the potential implications of utilizing ILs for enhancing the bioavailability and formulation versatility of ACP are considered. To accurately correlate the solubility data, various thermodynamic models were employed. Furthermore, to examine the observable thermodynamic characteristics of dissolution in the studied systems Van't Hoff and Gibbs equations were used. The findings indicated that the dissolution process in all co-solvents used was characterized by an endothermic nature and driven by enthalpy.

Lamellar Microphase Separation and Phase Transition of Hydrogen-Bonding/Crystalline Statistical Copolymers: Amide Functionalization at the Interface.

Microphase separation of random copolymers, as well as that of high χ-low N block copolymers, is promising to construct sub-10-nm structures into materials. Herein, we designed statistical copolymers consisting of 2-hydroxyethyl acrylate (HEA) and N-octadecylacrylamide (ODAAm) to produce crystallization and hydrogen bond-assisted lamellar structure materials. The copolymers not only formed a crystalline lamellar structure with 3-4 nm domain spacing but also maintained an amorphous lamellar structure via phase transition above the melting temperature up to approximately 100 °C. The key is to introduce hydrogen-bonding amide junctions between the octadecyl groups and the polymer backbones, by which the polymer chains are physically fixed at the interface of lamellar structures even above the melting temperature. The stabilization of the lamellar structure by the amide units is also supported by the fact that the lamellar structure of all-acrylate random copolymers bearing hydroxyethyl and crystalline octadecyl groups is disordered above the melting temperature. By spin-coating on a silicon substrate, the HEA/ODAAm copolymer formed a multilayered lamellar thin film consisting of a hydrophilic hydroxyethyl/main chain phase and a hydrophobic octadecyl phase. The structure and order-disorder transition were analyzed by neutron reflectivity.

White-light clusteroluminescence of poly(β-hydroxyvinyl N-substituted carbamate)s via through-space interactions

White-light-emitting polymers have attracted considerable attention in the fields of solid-state lighting and flexible displays. However, achieving white light emission from single-component polymers, particularly in clusteroluminescence (CL) polymers, remains a significant challenge. Herein, we synthesize three non-conjugated luminescent poly(β-hydroxyvinyl N-substituted carbamate)s (PHNCs): PHNCs-C with steric cyclohexyl groups, PHNCs-E with side hydroxyethyl groups, and PHNCs-H with flexible n-hexyl carbon chains. All PHNCs show excitation-independent emission, which transitions to excitation-dependent emission as the excitation wavelengths increase. It is proposed that these emissions originate from the π*→n transition of carbamate in hydroxyurethane and CL of hydroxyurethane, respectively. PHNCs-C exhibits the strongest CL and possesses the highest quantum yield (17.9 %) in solution, a performance that surpasses both PHNCs-E and PHNCs-H. This finding implies that a rigid structure can enhance and stabilize the through-space interactions (TSIs) of hydroxyurethane groups, resulting in a wide cluster-size distribution and white-light emission. Theoretical calculations corroborate these experimental results, further revealing that TSIs occur between the oxygen atoms of hydroxyurethane groups, namely, through-space n-n interactions of oxygen atoms. This work not only provides valuable insights into the nature of CL and TSIs, but also offers a novel approach to preparing single-component white-light-emitting CL polymers.

Characterization of the decomposition behaviors of catalytic pyrolysis of alkaline lignin with the addition of different concentrations of potassium

Investigating the influence of potassium concentration on alkali lignin pyrolysis is beneficial for advancing the technology of biomass catalytic pyrolysis. This study examined the catalytic effects of different concentrations of various potassium compounds on alkali lignin pyrolysis. The impregnation method was employed to load potassium compounds (KCl, K2CO3, and CH3COOK) onto alkali lignin at varying concentrations. The results showed a significant influence of potassium concentration on the catalytic pyrolysis of lignin. Increasing the potassium concentration resulted in higher pyrolysis char yield and lower pyrolysis gas yield. Furthermore, the pyrolytic char with a high concentration of potassium exhibited a distinct surface pore structure that was noticeably eroded by potassium. Furthermore, with an increase in potassium concentration, the removal of side chains, including methoxy, acetyl, and hydroxyethyl groups, became increasingly pronounced, resulting in higher yields of CO2 and phenol. The elevated potassium concentration facilitated the depolymerization of lignin through Cβ-O bond cleavage, promoted the decomposition of intermediate products, and enhanced the formation of small molecule products. Ultimately, a hypothetical mechanism explaining the influence of potassium concentration on alkali lignin pyrolysis was proposed. This study establishes a scientific foundation for the high-value utilization and resource development of alkaline lignin.

Surface Activity, Wetting, and Aggregation of a Perfluoropolyether Quaternary Ammonium Salt Surfactant with a Hydroxyethyl Group.

This paper reports the synthesis of a novel quaternary surfactant containing a hydroxyethyl group (PFPE-C) and the surface properties of its aqueous solution (investigated by comparisons with two structurally similar chemicals, dodecyl-(2-hydroxyethyl)-dimethylammonium chloride (DHDAC) and PFPE-A). The minimum surface tension (γCMC) and critical micelle concentration (CMC) of the PFPE-C aqueous solution were 17.35 mN/m and 0.024 mmol/L, respectively. This study confirms that surfactants containing hydroxyethyl groups efficiently reduce the surface tension of aqueous solutions, and fluorocarbon surfactants exhibit better surface activity than ordinary hydrocarbon surfactants with similar structures. The micellization, aggregation, air-water interfacial adsorption, and wettability of PFPE-C aqueous solutions have been systematically investigated. Highly concentrated PFPE-C aqueous solutions exhibit good wettability on PTFE and paraffin films. Moreover, the aggregates of PFPE-C in the aqueous solution were clearly seen as vesicles on Cryo-TEM micrographs. Primary biodegradation results indicate that 19% of PFPC-C can be degraded within one week.

Structure-activity relationships for hydration inhibition and environmental protection with modified branched polyethyleneimine: Experiments and simulations

Inhibiting the surface hydration of clay is the main task for the water-based drilling fluids used in the development of shale gas. Branching polyethyleneimine (BPEI) completely inhibits the clay surface hydration. However, the use of BPEI is limited by its high toxicity. In this paper, BPEI was modified by grafting with hydroxyethyl groups to reduce the toxicities of BPEI hydration inhibitors. The structures and properties of the modified BPEI were characterized by infrared spectroscopy, mass spectrometry, the luminescent bacteria method, isothermal adsorption, X-ray diffraction, thermogravimetric analysis, contact angle measurement, scanning electron microscopy, X-ray photoelectron spectroscopy and molecular simulations. The relative luminescence rate of the modified BPEI inhibitors increased from 14 % to 62 % with increases in the number of grafted hydroxyethyl groups. After hydrated sodium montmorillonite (Na–Mt) contacted the modified BPEI inhibitors, the basal spacings of the Na–Mt decreased from 1.90 nm to a minimum of 1.40 nm, and the DTG curve had only one low-temperature peak. Molecular simulations showed that the energy for adsorption of the inhibitor on the Mt surface increased with increases in the number of grafted hydroxyethyl groups. These results suggested a structure-activity relationship for inhibition and the biological toxicity of the modified BPEI inhibitor. That is, within the range of 20:1 to 5:1 for the molar ratios of amino and hydroxyl groups, increases in the number of grafted hydroxyethyl groups gradually decreased the biological toxicities of BPEI inhibitors, and the inhibition performance was gradually enhanced. BPEI-OH4 (amino:hydroxyl = 5:1) showed the best performance among the modified BPEI inhibitors. This provides an excellent inhibitor and a low-toxicity modification method, which will facilitate the development of environmentally friendly high-performance water-based drilling fluids.

Synthesis and flotation performance of a novel low-foam viscous cationic collector based on hematite reverse flotation desilication system

Traditional cationic collectors generally exist some disadvantages, such as high foam viscosity and difficulty in defoaming, which worsening the flotation separation effect. Herein, a novel cationic collector-dodecyl trihydroxyethyl ammonium bromide (DTDAB) with low-foam viscous was synthesized to optimize the reverse flotation system of hematite ore, which was achieved by introducing three hydroxyethyl groups into the nitrogen atoms of dodecyl trimethyl ammonium bromide (DTAB). The analysis of foam collapse performance indicated that the introduction of hydroxyl groups into hydrophilic head groups of DTAB reduced the interface surface tension and bubble coalescence, which were consistent with the design expectations. Meanwhile, flotation behaviors were systematically studied, and the results showed that the concentrates with 63.89 % total iron (TFe) grade and 89.27 % total iron recovery was obtained at pH 6.81, when the concentration of DTDAB and starch was 20 mg/L and 5 mg/L, respectively. Besides, the possible flotation mechanism was further studied by means of contact angle, Atomic force microscope (AFM), Fourier transforming infrared spectra (FT-IR), X ray photoelectron spectroscopy (XPS), and Density functional theory (DFT) calculation. The results comfirmed that the adsorption between DTDAB and quartz was caused by electrostatic force and hydrogen bonding affinity. In conclusion, it can be confirmed that the novel cationic collector DTDAB with low-foam viscous has the potential for the hematite reverse flotation desilication.

Interactions of hydrolyzed β-lactams with the L1 metallo-β-lactamase: Crystallography supports stereoselective binding of cephem/carbapenem products

L1 is a dizinc subclass B3 metallo-β-lactamase (MBL) that hydrolyzes most β-lactam antibiotics and is a key resistance determinant in the Gram-negative pathogen Stenotrophomonas maltophilia, an important cause of nosocomial infections in immunocompromised patients. L1 is not usefully inhibited by MBL inhibitors in clinical trials, underlying the need for further studies on L1 structure and mechanism. We describe kinetic studies and crystal structures of L1 in complex with hydrolyzed β-lactams from the penam (mecillinam), cephem (cefoxitin/cefmetazole), and carbapenem (tebipenem, doripenem, and panipenem) classes. Despite differences in their structures, all the β-lactam-derived products hydrogen bond to Tyr33, Ser221, and Ser225 and are stabilized by interactions with a conserved hydrophobic pocket. The carbapenem products were modeled as Δ1-imines, with (2S)-stereochemistry. Their binding mode is determined by the presence of a 1β-methyl substituent: the Zn-bridging hydroxide either interacts with the C-6 hydroxyethyl group (1β-hydrogen-containing carbapenems) or is displaced by the C-6 carboxylate (1β-methyl-containing carbapenems). Unexpectedly, the mecillinam product is a rearranged N-formyl amide rather than penicilloic acid, with the N-formyl oxygen interacting with the Zn-bridging hydroxide. NMR studies imply mecillinam rearrangement can occur nonenzymatically in solution. Cephem-derived imine products are bound with (3R)-stereochemistry and retain their 3' leaving groups, likely representing stable endpoints, rather than intermediates, in MBL-catalyzed hydrolysis. Our structures show preferential complex formation by carbapenem- and cephem-derived species protonated on the equivalent (β) faces and so identify interactions that stabilize diverse hydrolyzed antibiotics. These results may be exploited in developing antibiotics, and β-lactamase inhibitors, that form long-lasting complexes with dizinc MBLs.

Facile Hydrogels of AIEgens Applied as Reusable Sensors for In Situ and Early Warning of Metallic Corrosion

Early detection of metallic corrosion is one considerable method to reduce imperceptible disasters nowadays. Fluorescent coatings with high sensitivity and long lifetimes for use in the early detection of metallic corrosion are in high demand, but they are presently difficult to prepare. Inspired by the chameleon's skin, which is capable of switching its color in different atmospheres sensitively and reversibly, we proposed herein a facile and universal all-in-one strategy of combining the fluorescent sensitivity and dynamic hydrogen bonds in a hydrogel to develop a reusable corrosion detection tape to cover metal surfaces. The fluorescent hydrogel tape was constructed using free radical copolymerization of monomers [hydroxyethyl methylacrylate (HEMA) and tetraphenylethene derivatives (TPEPy)]. Due to the aggregation-induced emission (AIE) behavior of TPEPy, the poly(HEMA-co-TPEPy) hydrogel is capable of monitoring the traces of corrosion via the release of ferric ions with a concentration as low as 10-5 M. Moreover, due to the dynamic hydrogen bonds of hydroxyethyl groups in hydrogel networks, the fluorescent hydrogel tape exhibited good adhesion and well reusability for over 10 applications to effectively warn against early corrosion of stainless steel. This non-destructive and reversible method of early corrosion detection can provide valuable signals when maintenance is needed before the metal suffers serious damage.

Tuning side group structures of series-connected di-cations to achieve improved electrodialysis acid recovery performances

The electrodialysis (ED) technology for waste acids recovery has become a hotspot due to the advantages of low cost, high efficiency and no-pollution. The ED acid recovery efficiency is strongly controlled by the ionomer aggregation structure of the applied anion exchange membrane (AEM). To investigate the effects of different side group structures on the ED acid recovery performance of AEMs, a series of series-connected di-cation ionomers based AEMs named QPPO-DABCO-R with high ion exchange capacities were tailor-made from the commercial polyphenylene oxide with series-connected 1,4-diazabicyclo[2.2.2]octane di-cation groups as the transport cores, and hydroxyethyl, methyl and hexyl groups of various hydrophilic-hydrophobic balances as the auxiliary side groups. The aggregation structure, water uptake, mechanical properties, thermal stability, ion selectivity and ED acid recovery performance of the AEMs were systematically investigated. The results confirm that the modified microphase separation structures with the strong hydrophobic side groups show the enhanced abilities to increase the fixed charge density, to block proton leakage and promote the transport of counterions through the membrane. Interestingly, QPPO-DABCO-C6 with the most hydrophobic side group exhibits the acid recovery performances much better than those of the commercial acid block ACM. The results demonstrate convincingly that the strategy of combining appropriately sized hydrophobic weak polar alkyl groups with high-density series-connected di-ions is an effective method to develop electrodialysis AEM with excellent acid recovery performance.

The use of ethoxylated surfactants in flotation concentration of potash ores

This paper studies the use of ethoxylated surfactants (alkylphenols and alkylamines) as flotation collectors for water-insoluble silicatecarbonate impurities contained in potash ores, which form fine slime particles during ore grinding. The highest collector efficiency in flotation desliming of potash ores is achieved with 35 to 45 hydroxyethyl groups in the hydrocarbon radical of the collector. The paper studies the performance of cardanol polyethylene glycol ether, regarded as an alternative slime collector to oxyethylated alkylphenols and alkylamines (currently used at potash flotation plants). It has been shown that in the case of slime flotation in saturated solutions of potassium and sodium chlorides, both when using oxyethylated alkylamines and alkylphenols, as well as alkylcardanol, the best desliming performance is achieved when the hydrocarbon radical of the collector contains 40 ethylene oxide groups. Oxyethylated cardanol is a 100 % undissolved substance, non-flammable and highly soluble in water, with the melting point at around 45 °C. Studies using standard test objects of phyto- and zooplankton have established that the KE-40 flotation agent is not hazardous to the environment. This paper provides industrial use results for this new slime collector obtained in flotation concentration of sylvinite ores of the Verkhnekamskoe deposit. KE-40 enables efficient and selective flotation desliming of potash ores with different contents of water-insoluble silicate-carbonate and anhydrite impurities. It has been adopted for industrial use as an alternative slime collector by Uralkali PJSC.

Polymeric ionic liquids and ionic liquids of ionen type

A set of new experimental data was obtained regarding the influence of the structure of dimer ionene ionic liquids on their physical and chemical properties, which is the basis of the methodology for the synthesis of polymer ionene ionic liquids. It was established that the introduction of allyl and -hydroxyethyl groups into the quaternary nitrogen atom, the presence of a dibenzyl fragment at the cationic center and alkylaromatic radicals permit obtaining polymeric ionic liquids of the ionene type with a high level of ionic conductivity at a low glass transition temperature. Newly synthesized polymeric ionic liquids and ionene ionic liquids based on 1,2-epoxy-4,7-dioxononen-8 and tetrahydro-1,4-oxazine derivatives with an ionic conductivity of ~10–1–10–4 S cm–1 with glass transition temperature range of –1400С to –160С exhibited five to six orders of magnitude higher ionic conductivity as compared with known analogues. Recommendations for solving the problem of developing polymeric ionic liquids and ionene ionic liquids exhibiting high ionic conductivity while maintaining their liquid state in a wide temperature range have been developed.

Thermodynamics on the complexation of uranium (VI) with N-methylethylenediamine-N,N′,N'-triacetic acid in aqueous Solution: Potentiometry and microcalorimetry

Stability constants and enthalpies of N-methylethylenediamine-N,N′,N'-triacetic acid (MEDTA, denoted as H3L) complexes with uranyl were measured using potentiometry and microcalorimetry, I = 1.0 mol L−1 NaClO4 solution at 25 °C. Thermodynamic analyses revealed three U(VI)/MEDTA complexes: UO2(HL), UO2L−, and UO2(OH)L2−. The results showed that the complex formation of UO2L− (UO22+ ​+ ​L3− = UO2L−) is endothermic and driven solely by entropy. MEDTA in the UO2L− complex is a tetradentate and coordinates with U(VI) along the ethylenediamine backbone. Stability constant of mononuclear uranyl complex with MEDTA (UO2L−) is lower than UO22+/EDDA complex but higher than UO22+/HEDTA complex, indicating that dangling acetate arm of MEDTA or hydroxyethyl group of HEDTA would lower the stability.

N-substituted cyclic phosphoramides as flame-retardant and anti-dripping coatings for PET fabric

Fabric made of polyethylene terephthalate (PET) is a common textile that is widely used in daily life. Its flame retardancy has emerged as a major concern for lowering the risk of fire. As a kind of popular flame retardants, cyclic phosphoramides have been widely applied to improve the flame retardancy of various inflammable materials. To achieve more suitable and effective flame retardants for PET fabric, the fire-safety capabilities of PET fabric coated with various cyclic phosphoramides substituted by siloxane (PDPTP), hydroxyphenyl (DPHBP), and hydroxyethyl (PDNP) groups was explored in this work. All of these chemicals can successfully prevent PET fabric from melting and burning, providing it good flame retardancy and non-dripping performance. LOI values for PET fabrics coated with PDPTP, DPHBP and PDNP increased to 24.6, 25.2, and 30.3% under comparison loadings. These flame-retardant coatings enhanced the char-forming capacity for PET fabric. The residues at 700 °C increased to 26.5 and 27.4% for PDPTP and PDNP coated fabric in N2 atmosphere compared with 2.9% for pure fabric. Peak heat release rate (PHRR) and total heat release (THR) was effectively restrained by 50% and 35%, respectively. Fortunately, these flame-retardant coatings had no detrimental effects on the mechanical characteristics of PET fabric and even enhanced the weft's tensile breaking forces. Apart from DPHBP significantly reducing the fabric's whiteness, the whiteness of PDPTP and PDNP coated PET fabric hardly changed. The effect of cyclic phosphoramides with various substitutions on the flame retardancy of PET fabric is thoroughly discussed in this paper, which might be useful in the development of more effective flame retardants for PET materials.