Trimethyl Phosphate Research Articles

A practical dinucleotide phosphoramidite chemistry for de novo DNA synthesis via block coupling

With the development of synthetic biology, the demand for high-quality long oligonucleotides is increasing. The use of dinucleotide phosphoramidites (dimer amidites) will reduce half of the steps required in the stepwise monomer condensation, which is expected to lead to the high-quality synthesis of oligonucleotides. Herein, we report a convenient, unified procedure for the sustainable preparation of fully protected dimer amidites bearing a methyl phosphate and a β-cyanoethyl phosphoramidite. Key precursors of those amidites—dimers containing a 3′-hydroxyl group—have been prepared in high yield using a one-pot, scalable approach. The structures of all 16 dimer amidites and corresponding 3ʹ-hydroxyl dimers were confirmed by HPLC-MS and 31P NMR spectra. With these dimer amidites, modification of the standard method for automated solid-phase oligonucleotide synthesis enables high-yield block couplings. Oligonucleotides synthesized following this method are of sufficient quality to assemble gene-length DNA fragments. As a consequence, we develop a practical dinucleotide phosphoramidite chemistry for de novo DNA synthesis.

Manipulating the ionic conductivity and interfacial compatibility of polymer-in-dual-salt electrolytes enables extended-temperature quasi-solid metal batteries

Solid polymer electrolytes (SPEs) have shown great promise in the development of lithium-metal batteries (LMBs), but SPEs’ interfacial instability and limited ionic conductivity still prevent their widespread applications. Herein, high-concentration hybrid dual-salt “polymer-in-salt” electrolytes (HDPEs) through formulation optimization were facilely prepared to simultaneously boost ionic conductivity, improve interfacial compatibility, and ensure a wide-temperature-range operation with high safety. An optimized electrolyte (HDPE-0.6) shows negligible corrosion to the aluminum current collector after manipulating the salt ratio of lithium bis(trifluoromethane)sulfonimide and lithium bis(oxalato)borate. In addition, HDPE-0.6 has excellent ionic conductivity (i.e., ∼0.536, ∼0.898, and ∼1.28 mS cm−1 at 0, 30, and 60 °C), approaching 1 mS cm−1 at room temperature. Furthermore, HDPE-0.6 exhibits a high lithium transference number of 0.6 and a high electrochemical oxidation stability potential of > 4.8 V vs. Li/Li+. Additionally, due to the formulation of high-concentration thermally stable lithium salts and the employment of flame-retardant trimethyl phosphate as the solvent, HDPE-0.6 has no safety issues. The resultant LiFePO4|HDPE-0.6|Li cell exhibits high discharge capacity, good rate capability, and excellent cycle stability at extended temperatures of 0, 30, and 60 °C. By coupling theoretical calculations and in-depth X-ray photoelectron spectroscopy, we attribute the excellent cycle stability to the formation of a stable interphase. Moreover, our formulation strategy is suitable for the Na3V2(PO4)3//Na battery when replacing the lithium salts with sodium salts (i.e., sodium bis(trifluoromethane)sulfonimide and sodium bis(oxalato)borate) to yield HDPE-0.6-Na, as demonstrated by excellent cycle stability (e.g., 98.6 % of capacity retention after 300 cycles). Our work demonstrates that the as-developed quasi-solid HDPEs are suitable for LMBs and sodium-metal batteries, and HDPEs can function normally in a wide temperature range.

Probing the reactivity of protonated oxygen intermediate in aprotic media with in situ surface-enhanced infrared spectroscopy

A fundamental understanding of electrochemical reactions is essential to drive the practicality of batteries. The oxygen reduction reaction (ORR) that occurs on discharge in aprotic lithium-oxygen (Li-O2) batteries, invariably encounters interference from impurities (e.g., protons) in practical environments. It has been shown that moderate proton-mediated ORR can improve discharge capacity without altering the overall pathway; however, the reactivity of protonated oxygen intermediates formed towards aprotic electrolytes during ORR, remains controversial and unexplored. Herein, we interrogate the reactivity of protonated oxygen intermediates at the model Au | propylene carbonate and Au | trimethyl phosphate interfaces containing phenol as the moderate proton source, using in situ attenuated total reflection surface-enhanced infrared spectroscopy coupled with theoretical calculations. Direct spectroscopic evidence presents that the preferential reaction between superoxide and available protons to form protonated oxygen intermediates (e.g., HO2), can significantly mitigate superoxide anion (O2−)-induced solvent degradations while not triggering additional secondary parasitic reactions. Consequently, practical Li-O2 batteries containing phenol have also exhibited improved electrochemical performance and reversibility. We believe that the fundamental insights will provide important lessons for future practical design (e.g., protons control of electrolytes) of Li-O2 batteries and other related electrochemical devices.

Thermophysical Properties for Alkylphosphonate and Alkylphosphate Compounds

Organophosphorus compounds have a wide range of applications; they are commonly used as drugs or pesticides or in the production of ion batteries. However, some organophosphorus compounds, which were developed as warfare nerve agents, are neurotoxic and potentially lethal to living organisms. On the basis of the literature search, certain properties of these compounds are not well known. Knowledge of thermodynamic properties and the availability of reliable data are fundamental in the development of methods for detecting, treating, and safely analyzing decontamination. For research purposes, substitutes, called simulants, which have similar molecular structures and properties but are less toxic, are often employed. This work presents a thermodynamic study of four organophosphorus nerve agent simulants: trimethyl phosphate, triethyl phosphate, dimethyl methylphosphonate, and diethyl methylphosphonate. Differential scanning calorimeter and a Tian–Calvet type calorimeter were used to analyze their phase behavior and measure the liquid heat capacities, respectively. Vapor pressures were experimentally determined with the static method. Ideal-gas heat capacities were calculated using the R1SM approach, which combines the rigid rotor–harmonic oscillator model, the one-dimensional hindered rotor model, and the mixing model. The results obtained were compared with the data from the literature and simultaneously correlated to obtain a highly reliable thermodynamic description.Graphical

Reshaping hydrogen bond network in aqueous-aprotic hybrid electrolyte to achieve highly selective ambient ammonia synthesis

Aqueous electrolytes are extensively applied in electrochemical nitrogen reduction reaction, while the overwhelming H2O always produce much protons, favoring the electron-stealing hydrogen evolution reaction (HER) and thus leaving the current ammonia synthesis much to be desired. Here, we propose an aqueous-aprotic hybrid electrolyte system by introducing trimethyl phosphate (TMP) as a cosolvent to achieve highly selective ammonia synthesis. TMP features higher Gutmann donors than that of H2O, preferring to serve as hydrogen bond (HB) acceptor and reshaping the HB network in the electrolyte. Molecular dynamics simulations suggest that, compared with H2O-H2O HB, the H2O-TMP HB exhibits longer lifetime and better stability. The intensified interaction between H2O and TMP weakens the interaction between H2O and H2O, which strengthens the O-H bond of H2O and makes it more difficult to be broken, thus greatly inhibiting the dissociation of H2O and leading to a suppressed HER activity. Correspondingly, a significantly improved NRR performance with a superior NH3 yield rate of 82.1 ± 2.7 μg h–1 mg–1 and an optimum Faradaic efficiency of 73.3 ± 2.7% is achieved in the H2O-TMP hybrid electrolyte, indicative of order of magnitude enhancement compared with that delivered in the conventional aqueous electrolyte.

Concentration levels and ecological risk assessment of typical organophosphate esters in representative surface waters of a megacity

Organophosphate esters (OPEs) have been widely used as flame retardants and plasticizers in consumer and industrial products. They have been found to have numerous exposure hazards. Recently, several OPEs have been detected in surface waters around the world, which may pose potential ecological risks to freshwater organisms. In this study, the concentration, spatial variation, and ecological risk of 15 OPEs in the Beiyun and Yongding rivers were unprecedentedly investigated by the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and risk quotient (RQ) method. The result showed that triethyl phosphate (TEP), tri (2-chloroisopropyl) phosphate (TCPP) were the most abundant OPEs with average concentrations of 55.53 ng/L and 42.29 ng/L, respectively. The concentrations of OPEs in the Beiyun River are higher than in the Yongding River, and their levels were higher in densely populated and industrial areas. The risk assessment showed that there was insignificant from OPEs to freshwater organisms in these rivers (RQs <0.1). The risk was higher downstream than upstream, which was related to human-intensive industrial activities downstream in the Yongding River. The ecological risk of OPEs in surface waters worldwide was estimated by joint probability curves (JPCs), and the result showed that there was a moderate risk for tri (2-chloroethyl) phosphate (TCEP), a low risk for trimethyl phosphate (TMP), and insignificant for other OPEs. In addition, the QSAR-ICE-SSD model was used to calculate the hazardous concentration for 5% (HC5). This result validated the feasibility and accuracy of this model in predicting acute data of OPEs and reducing biological experiments on the toxicity of OPEs. These results revealed the ecological risk of OPEs and provided the scientific basis for environmental managers.

Degradation of organophosphate flame retardants by a consortium of bacterial strains isolated from the To Lich river, Hanoi

Organophosphate flame retardants (OPFRs) are degraded by a consortium of 10 bacterial strains isolated from the To Lich river, contaminated with OPFRs. The bacterial consortium is cultured in an A-Cl medium supplemented individually with OPFRs (10 mg/l), resulting in optical density at 600 nm ranging from 1 to 1.5. The consortium of 10 bacterial strains exhibits the ability to degrade tris(2-ethylhexyl) phosphate (TEHP) by 98.5 and 100% after two and three days of cultivation, respectively. Triethyl phosphate (TEP) is also degraded by 76.1 and 100% after two and five days of cultivation, respectively. The degradation efficiency of trimethyl phosphate (TMP), tris(2-chloroethyl) phosphate (TCEP), tris(1,3-dichloro-2-propyl) phosphate (TCDPP), and tributoxy ethyl phosphate (TBEP) is also in the range of 97 to 100% after four days of cultivation. In the experiment adding a mixture of 7 substances in OPFRs at a concentration of 10 mg/l for each compound, only TEHP is completely degraded after six days of cultivation. The degradation efficiency of other OPFRs increases from 93.2 to 100% after six days of cultivation. Comparing the degradation rates of OPFRs in both experiments, the results indicate that the cultures supplemented with each compound individually exhibit a faster degradation rate than when a mixture of OPFRs compounds is added.

Sandwich-structure inspired super-tough and fire-resistant plywood containing vinyl acetate-ethylene based adhesive reinforced by melamine amino trimethyl phosphate and sodium lignosulfonate

The flammability of wood composite materials inevitably limits its broadly applications, inspired by the sandwich structure, we propose an intumescent flame-retardant vinyl acetate-ethylene based adhesive reinforced by melamine amino trimethyl phosphate and sodium lignosulfonate compounds (IFRs), then being incorporated in adhesive layer to prepare fire-proofing plywood. The formaldehyde-free adhesive incorporated with 23 wt% IFRs in plywood (FR plywood) resulted in a significant reduction in the peak heat release rate (pHRR, −51 %) and a great delay in time to pHRR (219 s) compared with that of the sample neat plywood. Additionally, the shear strength and bending strength of sample FR plywood present significant increase of 150 % and 73 %, respectively, compared to that of the neat plywood. By incorporating the IFRs into the plywood adhesive layers, low-flammability gasses can be released under heat to dilute flammable volatile gasses together with the wood decomposition in the gaseous phase, simultaneously, generated polyphosphoric acids to facilitate the charring of wood under heat, leading to a cohesive and dense phospho-carbonaceous structure in the condensed phase. Thus, this work provides an efficient and simple strategy to prepare fire-proofing plywood with excellent mechanical performance, is worth commercializing in plywood industry.

Interfacial polymerization mechanisms assisted flame retardancy process of low-flammable electrolytes on lithium anode

Thermal runaway is a hazardous risk, occurring more readily in high-energy–density lithium-ion batteries (LIBs), which leads to a rapid temperature rise and even combustion or explosion when using flammable electrolyte systems. Flame retardants (FRs), such as trimethyl phosphate (TMPa) and triethyl phosphate (TEP), are commonly utilized due to their effective flame suppression, low toxicity, and excellent thermal stability. However, the lack of in-depth understanding of the flame retardancy mechanism and solid electrolyte interphase (SEI) formation process has made the development of functional electrolytes difficult at present. In this study, we clarified the flame retardancy and interfacial reaction mechanisms of low-flammable TMPa localized high-concentration electrolytes (LHCE) using hybrid ab initio and reactive force field (HAIR) schemes. Long-term HAIR simulation reveals that phosphorous radicals produced by the decomposition of TMPa capture carbon radicals, encouraging their polymerization into low-flammable oligomers, while fluorine-containing solvents in the electrolyte capture hydrogen radicals and produce nonflammable hydrofluoric acid (HF). This synergistic flame retardancy mechanism provides essential atomic-level insights for the rational design of high-safety electrolytes in the future.

Fiber optic dimethyl methyl phosphate fiber optic sensor based on ZIF-8@Ag/PDDA composite film

A Michelson interference dimethyl methyl phosphate (DMMP) fiber sensor with a single-mode (SMF)-dislocated single-mode (DSMF)-hollow-core fiber (HCF) structure is proposed. To fabricate the Michelson interference structure of SMF-DSMF-HCF, one end of the DSMF was misaligned and fused to the SMF, the other end was fused to the HCF to generate a reflective surface. The structure, elemental composition, and surface morphology of ZIF-8@Ag were analyzed using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy after the ZIF-8@Ag/PDDA composite was coated on the surface of DSMF. The result shows that the sensitivity and the detection limit of the sensor are 45.71 dB/ppm and 0.1431 ppb, respectively, and the response/recovery time is around 14/12 s. The sensor also has excellent selectivity and stability.

High-throughput viscoelastic characterization of cells in hyperbolic microchannels.

Extensive research has demonstrated the potential of cell viscoelastic properties as intrinsic indicators of cell state, functionality, and disease. For this, several microfluidic techniques have been developed to measure cell viscoelasticity with high-throughput. However, current microchannel designs introduce complex stress distributions on cells, leading to inaccuracies in determining the stress-strain relationship and, consequently, the viscoelastic properties. Here, we introduce a novel approach using hyperbolic microchannels that enable precise measurements under a constant extensional stress and offer a straightforward stress-strain relationship, while operating at a measurement rate of up to 100 cells per second. We quantified the stresses acting in the channels using mechanical calibration particles made from polyacrylamide (PAAm) and found that the measurement buffer, a solution of methyl cellulose and phosphate buffered saline, shows strain-thickening following a power law up to 200 s-1. By measuring oil droplets with varying viscosities, we successfully detected changes in the relaxation times of the droplets and our approach could be used to get the interfacial tension and viscosity of liquid-liquid droplet systems from the same measurement. We further applied this methodology to PAAm microgel beads, demonstrating the accurate recovery of Young's moduli and the near-ideal elastic behavior of the beads. To explore the influence of altered cell viscoelasticity, we treated HL60 human leukemia cells with latrunculin B and nocodazole, resulting in clear changes in cell stiffness while relaxation times were only minimally affected. In conclusion, our approach offers a streamlined and time-efficient solution for assessing the viscoelastic properties of large cell populations and other microscale soft particles.

An experimental and kinetic modeling study of the auto-ignition delay times of trimethyl phosphate-in-air mixtures

Organophosphorus compounds (OPCs) are known to be combustion inhibitors (CI), fire suppressants, or flame retardant molecules (FRMs) for polymers and as surrogates (simulants) for the disposal or thermal degradation of chemical war agents (CWAs). Despite a significant number of studies on the mechanism of their action, OPCs’ combustion chemistry is still insufficiently understood. There is a need for further understanding of their auto-ignition and oxidation characteristics at relevant conditions (high pressures and low temperatures). This study reports on new data on the autoignition delays of Trimethyl Phosphate (TMP)-in-air mixtures obtained from experiments performed on a high-pressure shock tube (HPST) at pressures of 5 and 10 bar in the initial temperature range from 1200 to 2200 K. An updated TMP kinetic model deduced from the Glaude et al. model for the thermal degradation of OPCs is also proposed for the estimation of the autoignition delays of the studied mixtures by incorporating new reaction pathways and corresponding rate constants estimation of some reactions involving TMP and some intermediate products of its degradation. The results indicate that the proposed model is in satisfactory agreement with all the investigated mixtures.

Improving the Performance of Flame-Retarding Sodium Bis(Oxalato)Borate in Triethyl Phosphate Electrolyte for Sodium Ion Batteries

An ever-growing demand for energy storage has highlighted potential future resource constraints for Li-ion batteries (LIBs), in particular with respect to Li.1-3 With this in mind Na-ion batteries (NIBs) hold promise as a complementary technology to LIBs, particularly for stationary energy storage.4 To be competitive with LIBs, NIBs need to become fully competitive on cost and on capacity density.5-7 NIBs can however offer more than simply a cost competitive option to LIBs, with potential to offer improvements on both safety and sustainability. A number of cathode materials exist that can avoid many of the unanswered question around the sustainability of state-of-the-art LIB cathodes.3 However, to address safety concerns of LIBs it is impossible to ignore the electrolyte. State of the art electrolyte in LIBs, regularly LiPF6 in a mix of carbonates, is both toxic (by virtue of LiPF6 and to a limited extent ethylene carbonate) and flammable (by virtue of the electrolyte solvents). Importing the Na analogue of state-of-the-art LIB electrolytes (i.e. NaPF6 in carbonates) creates the same problems of flammability and toxicity currently seen in LIBs (albeit the toxicity of NaPF6 is lower than that of LiPF6).Recently Mogensen et al.8 proposed sodium bis(oxalato)borate (NaBOB) in trimethyl phosphate (TMP) electrolyte that overcame the flammability concerns of NaPF6 in carbonate electrolytes. In addition to non-flammability, the use of NaBOB instead of NaPF6 allowed for higher temperatures to be used and produced an electrolyte that was halogen free. Switching from TMP to triethyl phosphate (TEP) allowed for a relatively less-toxic electrolyte (NaBOB and TEP are listed by the European Chemical Agency as ‘harmful if swallowed’ in comparison to ‘harmful if swallowed, in contact with skin or inhaled’ for NaPF6 in carbonates, although limited research has been conducted on the toxicity of NaBOB and so this should be received with limited certainty) without sacrificing cell performance.9 However, hurdles remain for NaBOB in organophosphate electrolytes. Principal amongst these has been the poor solubility of NaBOB in most solvents and the difficulties transferring promising low mass-loading full cell results to higher mass-loading full cells. The low solubility of NaBOB limits the concentration of NaBOB in organophosphate electrolytes to < 0.4 M, producing electrolytes with relatively low conductivities (for NaBOB in TMP, 4.5 mS/cm, and in TEP, 5 mS/cm). N-methyl pyrrolidone (NMP) has previously been shown to increase the solubility of NaBOB when used as a cosolvent with TMP, with conductivity improved to 6.5 mS/cm without sacrificing non-flammability and promising cycling shown in low mass-loading full-cells.10 A range of alternative cosolvents were here investigated to increase the solubility of NaBOB in TEP. Of these, NMP, N,N-dimethyl formamide (DMF) and N,N-dimethyl acetamide (DMAc) were evaluated as cosolvents with TEP for near-commercial mass loading full-cells (Prussian white||hard carbon at ~ 2 mAh/cm2). To maintain non-flammable characteristics, the cosolvents had to be kept below 40% (v/v) for DMAc and DMF and below 60% (v/v) for NMP, resulting in electrolyte conductivities of 5.7, 6.9 and 6.0 mS/cm respectively. These nearly doubled the conductivity we observed for NaBOB in TEP of 3.5 mS/cm. However, all electrolytes examined showed large polarisation, suspected to be due a thick, resistive SEI. A range of strategies have been employed in order to reduce this polarisation, with particular focus on improved formation protocols (studying the effects of temperature, current density and electrochemical method of formation) and their use in concert with film forming additives. Future work will aim to understand the interplay between formation conditions, the resultant SEI formation and the cell polarization in an effort to translate promising low mass-loading full cell results to near-commercial mass-loading full cells.

Synergistic effect of lithium salt and trimethyl phosphate for enhanced interface stability in solid-state lithium metal batteries

Polymer electrolytes hold significant potential in solid-state battery applications due to their high flexibility and scalable manufacturing capabilities. However, it is still necessary to address the safety problems and poor rate performance. Herein, the synergistic effect of trimethyl phosphate (TMP) and lithium difluoro(oxalate)borate (LiDFOB) in the in-situ fabricated poly-butyl acrylate (PBA) quasi-solid electrolyte (QSE) is investigated. The non-flammable additive, TMP, has proven to combine with LiDFOB in the electrolytes as TMP-DFOB− pair. The TMP-DFOB− pair can promote the formation of a B–O, B–F, LiF, and Li3P containing solid electrolyte interphase (SEI) on the lithium anode, enabling stable lithium striping-plating processes. Besides, it enhances the formation of a LiF-rich cathode electrolyte interphase (CEI) and promotes intimate contact between the cathode active materials and PBA-QSE, thereby enhancing the rate performance. Therefore, the Li/PBA-LiDFOB-0.1TMP/LiFePO4 (LFP) cell delivers discharge capacity of 132 mAh g−1 with a remarkable capacity retention of 95.68 % after 500 cycles at 1 C. Even at 4 C, the discharge capacity reaches 92.1 mAh g−1. This non-flammable PBA-LiDFOB-TMP QSE exhibits potential application in high energy density systems. Furthermore, this work provides new insights into strategies for improving rate performance from lithium salts and functional additives aspects.

Endowing the Operability of Supercapacitors at High Temperatures by Regulating the Solvation Structure in Dilute Hybrid Electrolyte with Trimethyl Phosphate Cosolvent.

The redox stabilities of different oxygen donor solvents (C═O, P═O and S═O) and lithium salt anions for supercapacitors (SCs) electrolytes have been compared by calculating the frontier molecular orbital energy. Among six lithium difluoro(oxalate)borate (LiDFOB)-based mono-solvent electrolytes, the dilute LiDFOB-1,4-butyrolactone (GBL) electrolyte exhibits the highest operating voltage but suffers from electrolyte breakdown at elevated temperatures. Trimethyl phosphate (TMP) exhibits the highest redox stability and a strongly negative electrostatic potential (ESP), making it suitable for promoting the dissolution of LiDFOB as expected. Therefore, TMP is selected as a co-solvent into LiDFOB-GBL electrolyte to regulate Li+ solvation structure and improve the operability of electrolytes at high temperatures. The electrochemical stable potential window (ESPW) of 0.5m LiDFOB-G/T(5/5) hybrid electrolyte can reach 5.230 V. The activated carbon (AC)-based symmetric SC using 0.5m LiDFOB-G/T(5/5) hybrid electrolyte achieves a high energy density of 54.2Whkg-1 at 1.35kWkg-1 and the capacitance retention reaches 89.2% after 10000 cycles. The operating voltage of SC can be maintained above 2V when the temperature rises to 60°C.

Importance of First Cycle Conditions on the Electrochemical Performance of Hard Carbon and Prussian White Based Sodium‐Ion Batteries Using Fire Resistant, Fluorine‐Free Electrolyte

AbstractElectrolytes based on sodium bis(oxolato)borate (NaBOB) in organophosphates (trimethyl phosphate and triethyl phosphate (TEP)) have shown promise in sodium‐ion batteries when compared to conventional electrolytes in that they are fire resistant, fluorine‐free and are of lower toxicity. However, these electrolytes tend to exhibit low initial Coulombic efficiency and high overpotentials. We have here demonstrated that NaBOB in TEP can be used in cells with near‐commercial capacity loadings. Furthermore, we have shown that formation cycle conditions have a significant positive effect on the cell performance in these higher mass loading cells, and that modification of the formation cycle conditions can be used to increase the capacity retention, lower the overpotentials, and as such increase the rate capability. The viability of optimized formation protocols was also demonstrated in scaled up prototype cells.

A solubility-limited, non-protonic polar small molecule co-solvent reveals additive selection in inorganic zinc salts

Organic additives, like ester organic molecules, are greatly compatible with aqueous electrolyte with organic zinc salts, thus playing an enhanced role in electrochemical performance. However, due to poor compatibility, some organic molecules have never been attempted in low-cost inorganic zinc salt electrolytes for zinc ion batteries. Herein, for the first time, according to the limited intercalation of an non-protonic polar small molecule trimethyl phosphate (TMP) in ZnSO4 electrolytes, the regularity of additive selection based on inorganic zinc salts is revealed in depth. Generally, by adding a small percentage, TMP can interact with Zn2+ to modify the solvated structure, while getting preferentially adsorbed on the anode surface to reshape the water-rich electric double layer (EDL). Thereby, a stable electrode/molecule/solution hydrophobic interface is formed, effectively promoting desolvation and reduction process of Zn2+. The TMP additive achieve ultra-long lifespan in symmetrical cells with a 24-fold improvement increase for dendrite-free Zn plating/exfoliation (over 2000 h at 1 mA cm−2 and 1 mAh cm−2), enabling Zn//V2O5 full cell to achieve 3500 cycles with high capacity retention (71.4 %). This novel strategy reaffirms the importance of inorganic zinc salts in additive strategies, thus opening up new ways for designing stable and long-lived zinc anodes.

Characteristics, sources, bio-accessibility, and health risks of organophosphate esters in urban surface dust, soil, and dustfall in the arid city of Urumqi in China

Sixty-eight paired samples of urban surface dust and soil as well as four samples of atmospheric dustfall were collected from the arid city of Urumqi in Northwest China. Thirteen organophosphate esters (OPEs) in these samples were analyzed for the characteristics, sources, bio-accessibility, and health risks of OPEs. The studied OPEs were widely detected in the urban surface dust, soil, and dustfall, with Σ13OPEs (total concentration of 13 OPEs) of 1362, 164.0, and 1367 ng/g, respectively, dominated by tris(2-chloroethyle) phosphate (TCEP), tri(2-chloroisopropyl) phosphate (TCiPP), tri(1, 3-dichloroisopropyl) phosphate (TDCiPP) and tris(2-butoxyethyl) phosphate (TBOEP), TBOEP and tri(2-ethylhexyl) phosphate (TEHP), and TCEP, TCiPP, TBOEP, triphenyl phosphate and TEHP, respectively. The low and high frequency magnetic susceptibility of surface dust and urban soil might indicate the pollution of OPEs in them. Elevated levels of the Σ13OPEs in the surface dust and urban soil were found in the west, south, and northeast of Urumqi city. The total deposition flux of dustfall-bound 13 OPEs ranged from 86.5 to 143 ng/m2/day, with a mean of 105 ng/m2/day. OPEs in the surface dust and urban soil were associated with the emissions of indoor and outdoor products containing OPEs, the dry and wet deposition of atmosphere, and the emissions of traffic. Trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tri-isobutyl phosphate, TCEP, TCiPP, TDCiPP, and TBOEP in surface dust and urban soil had relatively high bio-accessibility. The bio-accessibility of OPEs was mainly affected by the physio-chemical properties of OPEs. The non-cancer and cancer risks of human exposure to OPEs in surface dust and urban soil were relatively low or negligible. The current research results may provide scientific supports for prevention and control of pollution and risks of OPEs.

Probing the Thermochemistry Properties and Rate Kinetics of Trimethyl Phosphate (TMP): An H-Atom Abstraction (HAA) Reactions Perspective.

Trimethyl Phosphate (TMP), an organophosphorus liquid compound, is valued for its versatile qualities and applications in various fields. In modern chemical research and industry, processes involving Trimethyl Phosphate are optimized for minimal negative environmental impact, and scientific advancement is driven by adherence to stringent regulations to provide sustainable solutions and resource preservation. Thermochemical insights enhance our understanding of monomer incorporation, initiation, and propagation energetics. This study comprehensively investigates the thermochemistry and rate kinetics that govern H-atom abstractions in TMP through advanced computational techniques. The theoretical framework encompasses methodologies for conducting conformer searches, exploring transition states, and performing energy calculations. This study calculates rate constants for eight H-atom abstraction reactions involving TMP with stable species, O2 (oxygen), H (hydrogen), and radicals [ȮH (hydroxyl), ĊH3 (methyl), CH3Ȯ (methoxy), HȮ2 (hydroperoxyl), ṄH2 (amino), and ĊN (cyano)], and further analogies are related to barrier heights. Bond dissociation energies are also determined, highlighting TMP's susceptibility to various reaction pathways. The discussion and findings elucidate the need for further experimental validation for practical applications of TMP in chemical synthesis, combustion, flame-retardant technologies, environmental processes, and pharmaceutical research.

Influence of Dipole Orientation of Zwitterionic Materials on Hemodialysis Membrane Interactions with Human Serum Proteins

Hemodialysis is a lifesaving treatment for end-stage renal disease (ESRD) that exploits semipermeable membranes to remove fluids and uremic toxins from ESRD patients. Polyethersulfone (PES) is the most common membrane that is currently used in Canadian hospitals and represents 93% of the market. Nevertheless, PES membranes have limited hemocompatibility, which triggers blood activation cascades, as the rate of morbidity and mortality in ESRD patients is still unacceptably high. Surface modification with zwitterionic (ZW) materials, which are well known for their strong dipole–dipole interactions and exceptional antifouling properties, has recently received increased attention in improving PES characteristics like roughness, wettability, and biocompatibility, which are crucial factors in dialysis efficiency. The hydration structures, dynamics, and interactions of ZWs are significantly dependent on the backbone structures, such as differences in carbon space length [CSL], conformation, functional groups, pendant groups, and charge distributions, and even minor changes in ZW structure can drastically alter their behavior. However, a systematic investigation of the impact of dipole orientation of ZW on the hemocompatibility of the membranes has not yet been investigated. This study offers a comprehensive exploration of the interactions between hemodialysis membranes and human serum proteins, emphasizing the pivotal role of the zwitterion dipole orientation. We utilize molecular docking techniques to predict protein–ligand interactions, offering insights into the binding sites and binding energy of these complexes. The effect of dipole orientation on the hemocompatibility of various ZW-modified PES membranes compared to the pristine PES has been investigated using 2-methacryloyloxyethyl phosphorylcholine (MPC), 2-((2-(methacryloyloxy)ethyl)dimethylammonio)ethyl methyl phosphate (MMP), and butyl (2-((2-(methacryloyloxy)ethyl)dimethylammonio)ethyl) phosphate (MBP) zwitterions with opposite dipole orientations. Results showed that the protein–ligand interactions and affinity energies displayed by the reverse dipole moment structures are remarkably different. It was demonstrated that the MBP–PES ligand had the lowest affinity energy to interact with all examined human serum proteins compared to the structure, which had an opposite dipole moment. As a result, this membrane surface has better antifouling properties and, thus, higher hemocompatibility, which directly correlates with greater efficiency of hemodialysis in patients.