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The enhancement of flame resistance and mechanical strength is critical for the utilization of rigid polyurethane foam (RPUF) composites. In this study, the efficient synergistic flame‐retardant system, incorporating dimethyl methylphosphonate (DMMP) and expandable graphite (EG), with the addition of refined alkali lignin (A‐lignin) were aimed to superior fire resistance and mechanical integrity for RPUF. Furthermore, the flame retardancy and charring ability of obtained RPUF were obviously enhanced. Notably, an RPUF mixture containing A‐lignin, DMMP, and EG demonstrated substantial charring at elevated temperatures, improved limiting oxygen index, and met the UL‐94 V‐0 rating. Cone calorimeter test indicated that this formulation produces less heat and smoke than pure RPUF. The flame‐retardant efficacy of obtained RPUF was attributed to the formation of a protective char layer coupled with the free radical neutralization properties of DMMP, collectively enhancing the flame retardancy obtained RPUF. Additionally, this RPUF variant showed significant advancements in both mechanical and thermal performance. This study outlines a successful strategy for developing RPUF composites endowed with enhanced flame retardancy and mechanical strengths. [ABSTRACT FROM AUTHOR]

Green manufacturing and reducing our cultural dependency on petrochemicals have been the global interest currently, especially in the polyurethane industry segments. We report the fabrication of rigid polyurethane foams (RPUFs) and their flame-retardant property from hemp seed oil as an alternative to petrochemical-based polyols. The cold-pressed hemp-seed oil (HSO) was first oxidized to epoxidized triglyceride oils with acetic acid and hydrogen peroxide, followed by a ring-opening reaction with methanol to fabricate hemp bio-polyols. The formation of polyols was characterized using FT-IR, hydroxyl, and acid values. The bio-polyol was used in different proportions with commercial polyols and other foaming ingredients to produce rigid polyurethane foams via a one-step process. Dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), and expandable graphite (EG) were added during the foam preparation to improve flame retardancy. The produced foams were analyzed for their apparent density, mechanical properties, thermal degradation behavior, closed cell content, flammability, and cellular morphology. The effect of different flame retardants had a significant influence on the cellular structures, closed-cell content, density, and compressive strength of the polyurethane. A significant improvement in anti-flaming properties was observed as the neat HSO-based foam showed a burning time of 110 s and a weight loss of 82%, whereas 10 wt% of TEP displayed a reduced burning time and weight loss of 19 s and 5%, respectively. DMMP and EG-based RPUFs exhibited similar flame retardancy and mechanical properties relative to neat HSO-based foam. The results demonstrated in this work proposed a potential combination of bio-polyols and commercial polyols as a strategy to fabricate flame-retardant polyurethane foam for high-performance applications. [ABSTRACT FROM AUTHOR]

With a rapid expansion in applications of epoxy resins (EP) and derived composites, there is a high demand for improving their flame retardant and dielectric properties. In this work, a facile and convenient strategy for loading a dimethyl methylphosphonate (DMMP) flame retardant into the channels of ZIF-8 (zeolitic imidazolate framework) was developed, followed by the assembly of a hybrid ZIF-8@DMMP material with epoxy resin (EP). The obtained MOF-containing hybrid EP composites, abbreviated as 820/EP (with 20 wt% ZIF-8) and 8 FR20/EP (with 20wt% ZIF-8@DMMP), were fully characterized and shown to feature superior flame retardant behavior, contributing to an enhanced safety of such material in terms of total smoke suppression, lower levels of total heat release and carbon monoxide generation. The results demonstrated that the formation of an intumescent dense char layer restrained further combustion, thus enabling this composite material to feature a better flame retardant performance. Besides, the composite exhibited a dielectric permittivity and dielectric loss of as low as 3.0 at a high frequency, which significantly outperforms the neat epoxy resin. This work thus showcases a simple and efficient route to enhance dielectric and flame retardant properties of polymeric epoxy resins, while merging the inherent porosity of ZIF-8 and traditional flame retardant behavior of DMMP. [ABSTRACT FROM AUTHOR]

Thermocatalytic decomposition is an efficient purification technology that is potentially applicable to degrading chemical warfare agents and industrial toxic gases. In particular, ZrO2 has attracted attention as a catalyst for the thermocatalytic decomposition of dimethyl methylphosphonate (DMMP), which is a simulant of the nerve gas sarin. However, the influence of the crystal phase and morphology on the catalytic performance of ZrO2 requires further exploration. In this study, monoclinic- and tetragonal-phase ZrO2 (m- and t-ZrO2, respectively) with nanoparticle, flower-like shape and hollow microsphere morphologies were prepared via hydrothermal and solvothermal methods, and their thermocatalytic decomposition of DMMP was systematically investigated. For a given morphology, m-ZrO2 performed better than t-ZrO2. For a given crystalline phase, the morphology of hollow microspheres resulted in the longest protection time. The exhaust gases generated by the thermocatalytic decomposition of DMMP mainly comprised H2, CO2, H2O and CH3OH, and the by-products were phosphorus oxide species. Thus, the deactivation of ZrO2 was attributed to the deposition of these phosphorous oxide species on the catalyst surface. These results are expected to help guide the development of catalysts for the safe disposal of chemical warfare agents. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

New and efficient sensors of nerve agents are urgently demanded to prevent them from causing mass casualties in war or terrorist attacks. So, in this work, a novel hierarchical nanoheterostructure was synthesized via the direct growth of α-Fe2O3 nanorods onto multiwall carbon nanotube (MWCNT) backbones. Then, the composites were functionalized with hexafluoroisopropanol (HFIP) and successfully applied to detect dimethyl methylphosphonate (DMMP)-sarin simulant gas. The observations show that the HFIP-α-Fe2O3@MWCNT hybrids exhibit outstanding DMMP-sensing performance, including low operating temperature (220 °C), high response (6.0 to 0.1 ppm DMMP), short response/recovery time (8.7 s/11.9 s), as well as low detection limit (63.92 ppb). The analysis of the sensing mechanism demonstrates that the perfect sensing performance is mainly due to the synergistic effect of the chemical interaction of DMMP with the heterostructure and the physical adsorption of DMMP by hydrogen bonds with HFIP that are grafted on the α-Fe2O3@MWCNTs composite. The huge specific surface area of HFIP-α-Fe2O3@MWCNTs composite is also one of the reasons for this enhanced performance. This work not only offers a promising and effective method for synthesizing sensitive materials for high-performance gas sensors but also provides insight into the sensing mechanism of DMMP. [ABSTRACT FROM AUTHOR]

The increasing threat of nerve agents has prompted the need for gas sensors with fast response, high sensitivity, and good stability. In this work, the hexafluoroisopropanol functional group was modified on a porous aromatic framework material, which served as a sensitive material for detecting dimethyl methylphosphonate. A nerve agent sensor was made by coating sensitive materials on a surface acoustic wave device. Lots of pores in sensitive materials effectively increase the specific surface area and provide channels for diffusion of gas molecules. The introduction of hexafluoroisopropanols enables the sensor to specifically adsorb dimethyl methylphosphonate and improves the selectivity of the sensor. As a result, the developed gas sensor was able to detect dimethyl methylphosphonate at 0.8 ppm with response/recovery times of 29.8/43.8 s, and the detection limit of the gas sensor is about 0.11 ppm. The effects of temperature and humidity on the sensor were studied. The results show that the baseline of the sensor has a linear relationship with temperature and humidity, and the temperature and humidity have a significant effect on the response of the sensor. Furthermore, a device for real-time detection of nerve agent is reported. This work provides a new strategy for developing a gas sensor for detecting nerve agents. [ABSTRACT FROM AUTHOR]

A molecular imprinted polymer (MIP) fabricated from a chitosan doped with graphite to create a conductive composite (CG-MIC) with the ability to trap and detect dimethyl methylphosphonate (DMMP) through a change in resistance of the material has been successfully manufactured. The GC-MIC presented a maximum trapping capacity of 96 ppm (0.096 mg g−1) of DMMP. A similar non-imprinted composite made of chitosan-graphite (CG-NIC) had a surface adsorption of 48 ppm (0.048 mg g−1) of DMMP. The manufacturing process was tested for consistency and there were no significant differences in resistance between batches of CG-MIC before (around 450 Ω) and after (around 70 Ω) DMMP extraction, representing a homogeneous manufacturing process. Although Atomic Force Microscopy studies revealed that the graphite was not homogenously distributed throughout the chitosan matrix, the response was consistent. The changes in the concentration of DMMP within the self-sensing material, being proportional to those in gas concentration, could be followed by the changes in resistance. The inclusion of common interferents: Acetic acid, acetone, ethanol, ammonium hydroxide and 2-propanol, equivalent in concentration to the DMMP, caused a change in the resistance of the material but did not substantially affect the specific resistance response of the composite material. Based on this data, the CG-MIC could be used as a smart material with sensing capabilities to monitor trapping levels of DMMP. [ABSTRACT FROM AUTHOR]

Granular activated carbon (GAC) has proven to be an effective adsorbent for removing the chemical warfare agent sarin (GB) and simulants like Dimethyl methylphosphonate (DMMP). However, it comes with certain limitations, including inadequate contact efficiency, notable mass transfer resistance, and lower bed utilization efficiency. This study synthesized steel fiber-entrapped activated carbon composites (SFEACs), which exhibited a maximum adsorption capacity of 285.3 mg/g at 303 K. Compared with the packed bed (PB) filled with GAC, while the adsorption capacity of SFEACS decreased, there was a substantial increase in the adsorption mass transfer rate. These SFEACs were combined with GAC to create a structural fixed bed (SFB), which demonstrated excellent performance in DMMP removal. Under identical experimental conditions, the DMMP breakthrough curve of SFB exhibited a steeper profile compared to the packed bed (PB) filled with GAC at the same bed height, and the breakthrough time against DMMP vapor could be extended by 13.8%. Furthermore, the adsorption rate constant of the Yoon-Nelson model increased by more than 17.6%, and the unused bed length, according to the Wheeler–Jonas model, decreased by more than 14%. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The inhibitory effect of dimethyl methylphosphonate (DMMP) on coal spontaneous combustion was investigated. The influence of DMMP on the thermal mass loss and thermal properties in the coal oxidation process was analyzed by synchronous thermal analysis. A DMMP inhibitor concentration of 10% provided the best inhibitory effect on coal oxidation. Addition of DMMP increased the coal ignition temperature by approximately 33°C, the burnout temperature by approximately 63°C, and the initial exothermal temperature by approximately 12°C. It also reduced the total heat release of the coal oxidation process by approximately 1200 J/g. Kinetic analysis of raw coal and DMMP-treated coal showed that DMMP exerted physical inhibition by blocking contact between coal and oxygen in the low-temperature oxidation stage. In the high-temperature oxidation stage, the chemical inhibition effect of DMMP was enhanced and the activation energy increased significantly (approximately 54.79 kJ/mol). Gas phase analysis indicated that DMMP could reduce oxygen consumption and CO emission during the coal oxidation process. On the basis of the above results and quantum chemical analysis, a mechanism for DMMP suppression of coal spontaneous combustion was proposed. This study provides reference data for prevention of coal spontaneous combustion and development of new inhibitors. [ABSTRACT FROM AUTHOR]

The catalytic performances of the catalysts and decomposition mechanisms of dimethyl methylphosphonate (DMMP), a commonly used nerve agent simulant, are well understood based on previous studies. However, the effects of the morphology of the catalyst on DMMP decomposition performance and mechanisms remain unexplored. Thus, in this work, experimental studies were conducted on the thermocatalytic decomposition of DMMP on CeO2 nanomaterials with different morphologies, e.g., irregular nanoparticles, nanorods, and nanocubes. From the performance evaluation, CeO2 nanorods exhibited higher DMMP thermocatalytic decomposition performance as compared to irregular nanoparticles and nanocubes. The primary reaction pathways were the same on all three morphologies of materials, according to in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study, whereas side reaction paths showed variable behaviors. According to the catalytic reaction mechanism study, the surface lattice oxygen played a vital role in the thermocatalytic decomposition of DMMP and the accumulation of phosphates, carbonates, and formates were the main factors for deactivation of the catalyst. The behavior of CeO2 catalyst with different morphologies in the thermocatalytic decomposition of DMMP was revealed in this work, and this will be useful for the future design of high-performing catalysts for the efficient degradation of chemical toxicant. [ABSTRACT FROM AUTHOR]

Our development of high surface-area mesoporous expressions of ceria (CeO2) is motivated by recent studies identifying CeO2 as one of the most reactive oxides for adsorbing and degrading toxic organophosphorus compounds, including chemical warfare simulants. We synthesize nanostructured CeO2 aerogels using a facile, scalable, and template-free sol–gel method to amplify the number of available and accessible surface sites for organophosphorus adsorption/degradation and then spectroscopically characterize the degradation of dimethyl methylphosphonate (DMMP) at the aerogel surface. The CeO2 aerogels retain high concentrations of surface-sited residual Cl from the chloride sol–gel precursors, which block DMMP binding sites and hinder the formation of surface hydroxyls (OH). We demonstrate that a simple alkaline soak removes surface-fouling Cl and creates a more OH-rich surface, thus unleashing the hydrolytic activity of the amplified CeO2 aerogel surfaces. Whereas the Cl-fouled CeO2 surface weakly and reversibly binds DMMP, the rinsed, OH-rich surface irreversibly binds DMMP and rapidly generates hydrolysis products. Exciting the CeO2 bandgap with UV light (390–400 nm) accelerates DMMP degradation and generates a higher proportion of mineralized POx products than the dark reaction. Our work marks the first-ever report of photodegradation of a chemical warfare simulant at CeO2 as well as the first report of mineralized POx formation at CeO2 at room temperature. The high surface-area CeO2 aerogels exhibit higher capacity than non-networked, nanoparticulate CeO2, thus highlighting the potential applicability of nanocrystalline CeO2 aerogels for protection against organophosphorus compounds. [ABSTRACT FROM AUTHOR]

Colorimetry is an important on-site detection method for organophosphorus compounds. O-Ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate (VX) is recognized as one of the deadliest organophosphorus chemical agents, and the rapid on-site detection of VX is of great significance to public safety. In this paper, a squaraine derivative was synthesized as probe molecules, and the sensing characteristics of VX in a colorimetric solution system containing tetrabutylammonium fluoride (TABF) were studied with UV−Vis spectroscopy, nuclear magnetic resonance (1H NMR), and mass spectrometry. The results showed that the binding of the thiol moiety of VX to the quaternary ring of the squaraine probe changed the molecular conjugation system, and that the rapid colorimetric detection of micro-trace VX was achieved based on color change before and after interaction with squaraine, enabling the detection limit of VX to be as low as 0.4 μg/mL. Moreover, the colorimetry method also possessed satisfactory sensitivity and could detect VX from other organophosphorus pesticides (e.g., parathion and dichlorvos), phosphorus-containing reagents (e.g., diethyl chlorophosphate and dimethyl methylphosphonate), a benzene series (e.g., toluene), and acid and base agents (e.g., acetic acid and triethylamine, respectively), which demonstrated that squaraine-based colorimetry could provide fast, on-site measurement results for VX detection. The strategy of this research could be extended as a common approach for the detection of other organophosphorus nerve agents or organophosphorus pesticides. [ABSTRACT FROM AUTHOR]

A colorless, odorless G nerve agent, a type of chemical transfer agent (CWA) that causes significant loss of life, is being studied for quick and accurate detection. In this study, detection materials with different functional groups were synthesized based on thiourea (TU)-decorated polyhedral oligomeric silsesquioxane (POSS) to study the most suitable material for the detection of dimethyl methylphosphonate (DMMP), a simulant of neural agents. The sensing material was coated on a SAW sensor with a resonance frequency of 250 MHz based on ST-quartz, the DMMP exposure experiment was conducted, and the performance of the sensing material was compared through frequency shift before and after exposure. Coating materials with excellent reactivity with DMMP and appropriate coating concentration for each material were identified at a concentration of 10 ppm. Among them, POSS-TU with 3,5-bis(trifluoromethyl)phenyl as a functional group showed the largest frequency shift characteristics, and it was used in low concentration (1, 5, and 10 ppm) DMMP detection experiments to confirm linear frequency shift characteristics according to low concentration. Finally, through a selectivity experiment with other gases, it was confirmed that the amount of frequency shift in other gases except DMMP was small, making it an excellent DMMP sensing material. [ABSTRACT FROM AUTHOR]

Zinc metal battery (ZMB) is promising as the next generation of energy storage system, but challenges relating to dendrites and corrosion of the zinc anode are restricting its practical application. Here, to stabilize Zn anode, we report a controlled electrolytic method for a monolithic solid‐electrolyte interphase (SEI) via a high dipole moment solvent dimethyl methylphosphonate (DMMP). The DMMP‐based electrolytes can generate a homogeneous and robust phosphate SEI (Zn3(PO4)2 and ZnP2O6). Benefiting from the protecting impact of this in situ monolithic SEI, the zinc electrode exhibits long‐term cycling of 4700 h and a high Coulombic efficiency 99.89 % in Zn|Zn and Zn|Cu cell, respectively. The full V2O5|Zn battery with DMMP‐H2O hybrid electrolyte exhibits a high capacity retention of 82.2 % following 4000 cycles under 5 A g−1. The first success in constructing the monolithic phosphate SEI will open a new avenue in electrolyte design for highly reversible and stable Zn metal anodes. [ABSTRACT FROM AUTHOR]

The increasing threat of nerve agents has prompted the need for gas sensors with fast response, high sensitivity, and good stability. In this work, the hexafluoroisopropanol functional group was modified on a porous aromatic framework material, which served as a sensitive material for detecting dimethyl methylphosphonate. A nerve agent sensor was made by coating sensitive materials on a surface acoustic wave device. Lots of pores in sensitive materials effectively increase the specific surface area and provide channels for diffusion of gas molecules. The introduction of hexafluoroisopropanols enables the sensor to specifically adsorb dimethyl methylphosphonate and improves the selectivity of the sensor. As a result, the developed gas sensor was able to detect dimethyl methylphosphonate at 0.8 ppm with response/recovery times of 29.8/43.8 s, and the detection limit of the gas sensor is about 0.11 ppm. The effects of temperature and humidity on the sensor were studied. The results show that the baseline of the sensor has a linear relationship with temperature and humidity, and the temperature and humidity have a significant effect on the response of the sensor. Furthermore, a device for real-time detection of nerve agent is reported. This work provides a new strategy for developing a gas sensor for detecting nerve agents.

Flame retardants (FRs) often reduce the mechanical properties of polymer materials, and FR/microcellular polyurethane elastomer (MPUE) composite materials have not been systemically studied. Hence, we conducted this study on FR/MPUE composites by using multiple liquid FRs and/or expandable graphite (EG). Compared with liquid flame retardants, the LOI of an expandable graphite/dimethyl methylphosphonate (EG/DMMP) (3:1) combination was significantly increased (~36.1%), and the vertical combustion grade reached V-0 without a dripping phenomenon. However, the corresponding tensile strength was decreased by 17.5%. With the incorporation of EG alone, although the corresponding LOI was not a match with that of DMMP/EG, there was no droplet phenomenon. In addition, even with 15 wt% of EG, there was no significant decline in the tensile strength. Cone calorimeter test results showed that PHRR, THR, PSPR, and TSR were significantly reduced, compared to the neat MPUE, when the EG content surpassed 10 wt%. The combustion process became more stable and thus the fire risk was highly reduced. It was found that flame retardancy and mechanical properties could be well balanced by adding EG alone. Our proposed strategy for synthesizing FR/MPUE composites with excellent flame retardancy and mechanical properties was easy, effective, low-cost and universal, which could have great practical significance in expanding the potential application fields of MPUEs. [ABSTRACT FROM AUTHOR]

Granular activated carbon (GAC) has proven to be an effective adsorbent for removing the chemical warfare agent sarin (GB) and simulants like Dimethyl methylphosphonate (DMMP). However, it comes with certain limitations, including inadequate contact efficiency, notable mass transfer resistance, and lower bed utilization efficiency. This study synthesized steel fiber-entrapped activated carbon composites (SFEACs), which exhibited a maximum adsorption capacity of 285.3 mg/g at 303 K. Compared with the packed bed (PB) filled with GAC, while the adsorption capacity of SFEACS decreased, there was a substantial increase in the adsorption mass transfer rate. These SFEACs were combined with GAC to create a structural fixed bed (SFB), which demonstrated excellent performance in DMMP removal. Under identical experimental conditions, the DMMP breakthrough curve of SFB exhibited a steeper profile compared to the packed bed (PB) filled with GAC at the same bed height, and the breakthrough time against DMMP vapor could be extended by 13.8%. Furthermore, the adsorption rate constant of the Yoon-Nelson model increased by more than 17.6%, and the unused bed length, according to the Wheeler–Jonas model, decreased by more than 14%.

Chemical warfare agents (CWAs) pose a significant threat to humans because of their high toxicity. Zirconium-based metal–organic frameworks (Zr-MOFs) are promising candidates for the purification and detoxification of CWAs. In this study, we prepared a Zr6O4(OH)8(H2O)4(abtc)2 denoted to Zr-abtc (abtc = 3,3′,5,5′-azobenzene-tetracarboxylate) under eco-friendly hydrothermal reflux conditions and investigated its detoxification performance. Dimethyl methylphosphonate (DMMP) was used as a simulant of a nerve agent to evaluate the adsorption performance of Zr–abtc. The Zr–abtc MOF was constructed from an 8-connected Zr6 cluster [Zr6(µ3-O)4(µ3-OH)4] with abtc as a linker, resulting in the generation of abundant surface hydroxyl groups, high porosity, and remarkable structural robustness under high moisture and high temperature conditions. The results of the breakthrough (BT) test of DMMP under dry and humid conditions reveal that Zr–abtc displays high DMMP adsorption performance with the adsorption capacity of 1.74 and 1.60 mmol/g under dry and humid condition, respectively. The high performance of Zr–abtc can be attributed to not only the strong interaction between the surface hydroxyl group of Zr–abtc MOF and DMMP but also the catalytic activity of the surface hydroxyl group to form the decomposed product of DMMP, as demonstrated using Fourier transform infrared spectroscopy (FTIR).

Organophosphorus (OPs) compounds have received enormous attention due to high neurotoxicity. However, the complex detection environment makes it very difficult to detect the OPs compounds at extremely low‐concentration. Therefore, it is vital to develop a high sensitive analytical method for the detection of low‐concentration OPs compounds at complex environment. Here, we proposed a novel surface‐enhanced Raman scattering (SERS) substrate based on the core‐shell structure Au@ZrO2 for the detection of extremely low‐concentration OPs compounds. By using above SERS substrate, we tested different kinds of OPs compounds and obtained excellent detection results. The detection limit of methyl parathion and triazophos can reach 0.01 mg/kg. Meanwhile, under the actual system (orange peel), the detection limit of the methyl parathion and triazophos also can reach 0.5 and 0.1 mg/kg, respectively. In addition, the above substrate is also very effective for the detection of dimethyl methylphosphonate (DMMP), a simulant for the chemical warfare agent (sarin), and the detection limit can reach 100 mg/kg. Besides, we also verified the reproducibility and stability of Au@ZrO2, which showed excellent properties. The relative standard deviation (RSD) of the SERS signal intensity for 20 tests was 6.38% and the enhancement ability of Au@ZrO2 can remain stable within 30 days. These results show that the proposed Au@ZrO2 SERS substrate has great potential in the detection of OPs compounds at extremely low‐concentration in the complex detection environment. [ABSTRACT FROM AUTHOR]

Aluminium-doped nickel ferrite (NiFeAl3+) nanoflakes were synthesized using the hydrothermal method. This nanocomposite material was used to fabricate a high-performance gas sensor for detecting dimethyl methylphosphonate, a stimulant of sarin gas (nerve agent). The fabricated sensor demonstrated a minimum detection limit of 0.1 ppm with a sensing response of 1.25%. The sensor was stable between temperatures of 200°C and 250°C. The sensing response decreased as the relative humidity increased. The sensor achieved response and recovery time of 24 s and 38 s, respectively, at a concentration of 1 ppm (250°C). The fabricated sensor demonstrated sensitivity of 14.654 ppm−1. The synthesized nanocomposite material was characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy and thermogravimetric analysis. The SEM analysis showed the formation of flakes and cube-like structures. The XRD pattern showed the crystalline nature of the nanocomposite. [ABSTRACT FROM AUTHOR]

The development of acrylic pressure‐sensitive adhesives (PSAs) with good flame retardancy is of great importance for the optoelectronic, automobile, and aircraft applications. However, a well‐known problem is that conventional flame retardants, while imparting good flame retardant properties to acrylic PSAs, compromise the cohesion and result in the unsatisfactory shear and peel strengths. In this work, flame‐retarded acrylic PSAs with improved shear and peel strengths were successfully prepared by constructing a tight non‐covalent crosslinking network that effectively counteract the negative effect of flame retardants on cohesion. In addition, the combination of dimethyl methylphosphonate (DMMP) and SiO2 increases the flame retardant effectiveness and reduces the overall required loading of flame retardants. As an example, when the amount of acrylic acid (AA) was 35 wt%, acrylic PSA containing 12.7 wt% DMMP and 2.5 wt% SiO2 particles showed well‐balanced adhesive properties and flame retardancy, with a shear strength of 3600 min and a peel strength of 15.0 N/25 mm, as well as a UL‐94 V‐0 rating. Meanwhile, it exhibited a high transmittance of above 90%. Furthermore, TG‐FTIR results confirmed that the flame‐retarded behaviors occurred in vapor phase. [ABSTRACT FROM AUTHOR]

Standoff chemical detection and identification techniques are necessary for ensuring safe exposure to dangerous substances. Molecular fingerprints of unknown chemicals can be measured using wavelength-tunable quantum cascade lasers operating in long-wavelength infrared. In this work, we present a method that can identify liquid chemicals on a reflective substrate via diffuse reflection spectra measurement from 50 cm away and multiple nonlinear regression analysis. Experimental measurements and numerical analyses were conducted for different chemical surface densities and angles of light incidence using diethyl phthalate (DEP) and dimethyl methylphosphonate (DMMP). Candidate substances can be classified using a deep learning model to reduce analysis time. [ABSTRACT FROM AUTHOR]

The kinetics of the reaction of hydroxyl radical (OH) with dimethyl methylphosphonate (DMMP, (CH3O)2CH3PO) (reaction 1) OH + DMMP → products (1) was studied at the bath gas (He) pressure of 1 bar over the 295–837 K temperature range. Hydroxyl radicals were produced in the fast reaction of electronically excited oxygen atoms O(1D) with H2O. The time-resolved kinetic profiles of hydroxyl radicals were recorded via UV absorption at around 308 nm using a DC discharge H2O/Ar lamp. The reaction rate constant exhibits a pronounced V-shaped temperature dependence, negative in the low temperature range, 295–530 K (the rate constant decreases with temperature), and positive in the elevated temperature range, 530–837 K (the rate constant increases with temperature), with a turning point at 530 ± 10 K. The rate constant could not be adequately fitted with a standard 3-parameter modified Arrhenius expression. The data were fitted with a 5-parameter expression as: k1 = 2.19 × 10−14(T/298)2.43exp(15.02 kJ mol−1/RT) + 1.71 × 10−10exp(−26.51 kJ mol−1/RT) cm3molecule−1s−1 (295–837 K). In addition, a theoretically predicted pressure dependence for such reactions was experimentally observed for the first time. [ABSTRACT FROM AUTHOR]

The dynamics of the dimethyl methylphosphonate (DMMP) radical cation after production by strong field adiabatic ionization have been investigated. Pump-probe experiments using strong field 1300 nm pulses to adiabatically ionize DMMP and a 800 nm non-ionizing probe induce coherent oscillations of the parent ion yield with a period of about 45 fs. The yields of two fragments, PO2C2H7+ and PO2CH4+, oscillate approximately out of phase with the parent ion, but with a slight phase shift relative to each other. We use electronic structure theory and nonadiabatic surface hopping dynamics to understand the underlying dynamics. The results show that while the cation oscillates on the ground state along the P=O bond stretch coordinate, the probe excites population to higher electronic states that can lead to fragments PO2C2H7+ and PO2CH4+. The computational results combined with the experimental observations indicate that the two conformers of DMMP that are populated under experimental conditions exhibit different dynamics after being excited to the higher electronic states of the cation leading to different dissociation products. These results highlight the potential usefulness of these pump-probe measurements as a tool to study conformer-specific dynamics in molecules of biological interest. [ABSTRACT FROM AUTHOR]

Aqueous zinc metal batteries (AZMBs) are deemed a promising technology for electrochemical energy storage due to their high safety, low cost, and high energy density. However, AZMBs still suffer from severe side reactions, including Zn dendrite formation and intrinsic hydrogen evolution reaction. In contrast to the solid‐electrolyte interphase (SEI) layer that stabilizes Li/Na/K metal anodes in organic electrolytes, it is difficult to form an SEI layer on the Zn surface because of the difficulty in decomposing the salt anions within the narrow electrochemical potential window of water. A team from the University of Adelaide reports a novel pure or hybrid electrolyte with H2O by using dimethyl methylphosphonate (DMMP) as solvent or co‐solvent to construct a uniform and stable phosphate‐based SEI layer (ZnP2O6 and Zn3(PO4)2). As a result, high Coulombic efficiencies and improved capacity retentions are obtained. [ABSTRACT FROM AUTHOR]

The catalytic performances of the catalysts and decomposition mechanisms of dimethyl methylphosphonate (DMMP), a commonly used nerve agent simulant, are well understood based on previous studies. However, the effects of the morphology of the catalyst on DMMP decomposition performance and mechanisms remain unexplored. Thus, in this work, experimental studies were conducted on the thermocatalytic decomposition of DMMP on CeO2 nanomaterials with different morphologies, e.g., irregular nanoparticles, nanorods, and nanocubes. From the performance evaluation, CeO2 nanorods exhibited higher DMMP thermocatalytic decomposition performance as compared to irregular nanoparticles and nanocubes. The primary reaction pathways were the same on all three morphologies of materials, according to in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study, whereas side reaction paths showed variable behaviors. According to the catalytic reaction mechanism study, the surface lattice oxygen played a vital role in the thermocatalytic decomposition of DMMP and the accumulation of phosphates, carbonates, and formates were the main factors for deactivation of the catalyst. The behavior of CeO2 catalyst with different morphologies in the thermocatalytic decomposition of DMMP was revealed in this work, and this will be useful for the future design of high-performing catalysts for the efficient degradation of chemical toxicant.

Two inorganic–organic hybrid isopolyoxoniobates (1 and 2) based on new high-nuclearity {Nb54O151} clusters have been synthesized under hydrothermal conditions. In particular, the combination of the unique {Nb54O151} clusters with copper-amine complexes has led to rare helical nanotubes, which are further linked by alkali metal cations or copper-amine complexes into two 2D similar bamboo-raft-like layered networks (1 and 2), respectively. Compound 1 exhibits effective base-catalytic decomposition of chemical warfare agent simulants dimethyl methylphosphonate (DMMP) and diethyl cyanophosphonate (DECP). [ABSTRACT FROM AUTHOR]

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Raman spectroscopy of gaseous molecules has been challenging, requiring complicated experimental procedures and peripheral devices for concentrating the analytes. Here, Raman spectroscopy of gaseous molecules at parts‐per‐billion (ppb) levels is demonstrated using aqueous microlenses of LiCl solution that spontaneously absorb water‐soluble gas molecules from the environment. The lenses are easily formed by filling the microwells of an elastomeric stamp with an aqueous solution of LiCl and stamping onto a substrate. Because LiCl is hygroscopic, the aqueous lenses maintain their liquid states under various ambient conditions. Gaseous molecules in the air dissolve in the aqueous microlens and can be identified based on their Raman fingerprints. Lowering the humidity causes the aqueous lens to transition into a salt crystal, while preserving the dissolved molecules within the crystal and facilitating the long‐term storage and analysis of gaseous analytes. By forming the aqueous microlenses on a surface‐enhanced Raman scattering (SERS) substrate, 800 ppb dimethyl methylphosphonate, a nerve agent simulant, is detected in a collection time of only 5 s. Aqueous microlenses that are responsive to the chemical environment are useful for analyzing various water‐soluble gaseous molecules and therefore have broad implications for healthcare, food safety, and environmental‐monitoring applications. [ABSTRACT FROM AUTHOR]

Nobel metal functionalized chemiresistive type metal-oxide sensors were fabricated and tested against hazardous gases such as acetone, ethanol, hydrogen sulfide, hydrogen cyanide and dimethyl methylphosphonate. WO 3 nanoflakes (NFs) were fabricated on Al 2 O 3 substrates by a facile hydrothermal route. 2D nanoflakes randomly aligned and uniformly covered on the substrate surface, and the thickness of the NFs were found approximately 100 nm. Then, Pt was loaded on WO 3 nanoflakes by RF sputtering method. According to the sensor tests, Pt modification tremendously improved the sensor performance of nanoflakes against acetone gas in terms of sensor response, selectivity among the measured gases and operation temperature. The spillover effect of Pt increased the sensing response and the sensor was able to selectively detect acetone with 237 particle per billion (ppb) at operation temperature of 250 ∘ C. Pt functionalization suppresses the sensor responses of NFs against gases (ethanol, hydrogen sulfide, hydrogen cyanide and dimethyl methylphosphonate) other than acetone. While pristine NFs sensor was able to sense these gases at low temperatures, Pt-functionalized WO 3 NFs did not sense at temperatures lower than 200 ∘ C by giving rise to the selectivity of the sensor against acetone. [ABSTRACT FROM AUTHOR]

Chemical warfare agents (CWA) are stockpiled in large quantities across the globe. Agents stored in inaccessible facilities need to be destroyed rapidly without dispersing the compounds to surrounding areas. Metal-based energetic formulations are used in such prompt defeat applications to rapidly decompose the CWA by generating a high temperature environment. An alternate, and possibly a more effective decomposition pathway could be provided by chemicidal action of aerosolized condensed combustion products, which typically consist of metal oxides. Toxic fumes that escape the high temperature blast zone can be neutralized by smoke generated during combustion, depending on the particle size, surface characteristics, chemical properties, and concentration of this smoke. This review considers relevant experimental and modeling studies quantifying decomposition of CWA comprising organophosphorus compounds and their surrogates on the surface of various metal oxides. Dimethyl methylphosphonate (DMMP), a sarine surrogate, was used most commonly for such experiments. Many reported efforts focused on the mechanisms of adsorption of DMMP to various metal oxides and initial reaction steps cleaving various bonds from the chemisorbed molecules. For selected oxides, these experiments were supported by quantum-mechanical calculations. In other studies, the capacity of oxide surfaces to adsorb and decompose DMMP was quantified. In most cases, porous catalysts were used although limited experimental data are available for aerosolized nonporous oxide particles. The reported experimental data applicable to scenarios involving prompt decomposition of CWA are summarized. It is noted that information is lacking describing respective heterogeneous reaction kinetics. Preliminary estimates of aerosolized smoke particle concentrations required to destroy CWA are made considering gas phase diffusion rates and reported values of the oxide capacity to decompose CWA or their surrogates. [ABSTRACT FROM AUTHOR]

A low-cost differential mobility spectrometer (DMS) was constructed using polytetrafluoroethylene printed circuit boards with two pairs of gold electrodes. The printed circuit boards were used to construct the drift tube into which the gas samples are introduced by a carrier gas and ionized. The ionized gas moves toward the gold electrode to which an asymmetric voltage is applied. Only the ionized gas with the proper ion mobility leaves the electrode region and reach the detection electrodes to form the ion current. Traces of five chemical warfare agents, including dimethyl methylphosphonate, triethylamine, 2-diisopropylaminoethanol, diethylaminoethanol, and N, N-dimethylethanolamine, were prepared using the permeation tube method and introduced into the sensor. All of the chemicals show characteristic ion peak shifts in the electric field. The limits of detection for the analytes are less than 1 ng/L. The recovery time was less than 10 s and the response time is 2 s. The developed sensor exhibits the ability to detect and distinguish between these chemical warfare agents. [ABSTRACT FROM AUTHOR]

The kinetics of the reaction of hydroxyl radical (OH) with dimethyl methylphosphonate (DMMP, (CH3O)2CH3PO) (reaction 1) OH + DMMP → products (1) was studied at the bath gas (He) pressure of 1 bar over the 295–837 K temperature range. Hydroxyl radicals were produced in the fast reaction of electronically excited oxygen atoms O(1D) with H2O. The time-resolved kinetic profiles of hydroxyl radicals were recorded via UV absorption at around 308 nm using a DC discharge H2O/Ar lamp. The reaction rate constant exhibits a pronounced V-shaped temperature dependence, negative in the low temperature range, 295–530 K (the rate constant decreases with temperature), and positive in the elevated temperature range, 530–837 K (the rate constant increases with temperature), with a turning point at 530 ± 10 K. The rate constant could not be adequately fitted with a standard 3-parameter modified Arrhenius expression. The data were fitted with a 5-parameter expression as: k1 = 2.19 × 10−14(T/298)2.43exp(15.02 kJ mol−1/RT) + 1.71 × 10−10exp(−26.51 kJ mol−1/RT) cm3molecule−1s−1 (295–837 K). In addition, a theoretically predicted pressure dependence for such reactions was experimentally observed for the first time.

Metal organic frameworks (MOFs) containing zirconium secondary building units (SBUs) in UiO‐67 and related MOFs, are highly active for neutralizing both the chemical warfare agents and simulants, such as dimethyl methylphosphonate (DMMP). However, two recent publications gave conflicting reports of DMMP reaction with UiO‐67 under ultra high vacuum (UHV) conditions, with one reporting chemisorption and reaction (Wang et al., J Phys Chem C, 2017, 121, 11261–11272) and the other reporting only physisorption and reversible desorption (Ruffley et al., J Phys Chem C, 2019, 123, 19748–19758) from very similar temperature programmed desorption experiments. We show that the discrepancy between these experiments may be explained by different levels of missing linker defects in the UiO‐67 samples. We present density functional theory calculations showing that SBU sites having two‐adjacent missing linkers exhibit reaction barriers that are about 30 kJ/mol lower than SBU sites having a single missing linker. We also show that topology of the undercoordinated sites plays an important role in the reaction barrier under UHV conditions. [ABSTRACT FROM AUTHOR]

Multifunctional organophosphorus additives present opportunities to engineer epoxy networks with both enhanced mechanical properties and ultralow flammability. This paper describes a systematic investigation of the effect of dimethyl methylphosphonate (DMMP) on the mechanical and heat release properties of both conventional and inherently low flammability epoxy resins. The findings demonstrate that integration of DMMP into epoxy networks produces materials with outstanding flame retardance and increased stiffness. Thermogravimetric analysis of DMMP‐containing networks show that DMMP promotes considerable char formation, with char residue reaching very high levels, up to 55%, for DMMP‐containing deoxybenzoin networks. Microscale combustion calorimetry of all the DMMP‐containing networks exhibit 50% lower heat release capacity and total heat release rate values relative to formulations without DMMP. Moreover, vertical burn tests demonstrate that DMMP‐containing formulations burn slowly and self‐extinguish. Morphological analysis of the charred DMMP‐containing formulations shows a porous structure and mechanical characterization reveals 50% higher elastic modulus, and comparable yield stress, for networks containing DMMP relative to those without DMMP. Overall, this organophosphorus additive represents an opportunity to combine materials chemistry with mechanical enhancement mechanisms to achieve low heat release properties without the need for halogenated flame‐retardant additives. [ABSTRACT FROM AUTHOR]

Gas capture and sequestration are valuable properties of metal–organic frameworks (MOFs) driving tremendous interest in their use as filtration materials for chemical warfare agents. Recently, the Zr-based MOF UiO-67 was shown to effectively adsorb and decompose the nerve-agent simulant, dimethyl methylphosphonate (DMMP). Understanding mechanisms of MOF-agent interaction is challenging due to the need to distinguish between the roles of the MOF framework and its particular sites for the activation and sequestration process. Here, we demonstrate the quantitative tracking of both framework and binding component structures using in situ X-ray total scattering measurements of UiO-67 under DMMP exposure, pair distribution function analysis, and theoretical calculations. The sorption and desorption of DMMP within the pores, association with linker-deficient Zr6 cores, and decomposition to irreversibly bound methyl methylphosphonate were directly observed and analyzed with atomic resolution. Metal–organic frameworks have been shown to adsorb and decompose chemical warfare agents, but their mechanism of action is not completely understood. Here the authors quantitatively track the binding and decomposition product structures of nerve-agent simulant dimethyl methylphosphonate in host UiO-67 through in situ X-ray total scattering measurements, pair distribution function analysis, and density functional theory calculations. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) has been widely used as a sensing material in many studies as PPy gives out noticeable reactions towards varieties of vapours of acids, bases, alcohols, alkanes, and chemical warfare agent (CWA) simulants. However, due to dispersion and mechanical properties limitation, PPy in nanoparticles (PPy NPs) has been introduced. The combinations between PPy NPs and nanosized metal oxide have shown promising improvement in the sensitivity of a sensor due to the larger total surface area of detection. In this study, the potential of PPy NPs and polypyrrole-iron oxyhydroxide (PFFs) nanocomposite as sensing materials in detecting the CWA simulant, dimethyl methylphosphonate (DMMP), is investigated. PPy NPs and modified PFFs nanocomposite were successfully synthesised using chemical oxidative polymerisation. The formation of PPy NPs and the effect of iron-oxyhydroxide (FeOOH) on the chemical interaction, morphology, and size of PPy NPs were investigated using attenuated total reflection-Fourier transform infrared (ATR-FTIR), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). ATR-FTIR analysis showed that the modified PFFs nanocomposite was successfully produced through the presence of a sharp –OH peak. The size of the prepared PPy NPs and PFFs nanocomposite was observed in the range of 50 to 70 nm and 110 to 160 nm, respectively, through TEM analysis. The electrochemical behaviour of PPy NPs and PFFs nanocomposite towards DMMP was investigated using cyclic voltammetry (CV) where, in the presence of DMMP, PPy NPs and PFFs nanocomposite showed 24% and 21% current signal reduction, respectively. This suggests that both PPy NPs and PFFs nanocomposite are able to discriminate an electrical signal both with and without the presence of DMMP. [ABSTRACT FROM AUTHOR]

Chemical warfare agents, particularly nerve agents such as sarin, are exceptionally harmful and incredibly perilous to people. Thus, the sensitive detection of these gases is indispensable for reducing the risk of chemical weapons. Herein, we fabricated a room-temperature chemiresistive gas sensor based on two-dimensional few-layer tungsten diselenide (WSe2) nanosheets, which were prepared through a facile liquid-phase exfoliation method. The WSe2-based sensor has demonstrated sensitive and selective detection of dimethyl methylphosphonate (DMMP), which is a well-known simulant of the nerve agent sarin. The sensor based on WSe2 nanosheets revealed a high response reaching 8.91% to 10 ppm DMMP with a fast response time of 100 s. Furthermore, the sensor displayed reliable stability, excellent selectivity, and a low theoretical limit of detection of about 122 ppb. The enhanced sensing performance of WSe2 nanosheets can be ascribed to the increase of the specific surface area, which provides more active adsorption sites for DMMP molecules, thereby facilitating the charge transfer process between DMMP molecules and WSe2 nanosheets. Overall, our results indicate that two-dimensional transition metal dichalcogenide materials have the potential for the design and fabrication of high-performance nerve agent sensing devices. [ABSTRACT FROM AUTHOR]

The flame‐retardant rigid polyurethane foams (RPUF) were prepared by using modified ammonium polyphosphate (MAPP) combined with expandable graphite (EG) and dimethyl methylphosphonate (DMMP). The thermal stability, flame retardant property, and mechanical property of flame‐retardant RPUF were evaluated based on thermogravimetric analysis (TGA), limiting oxygen index (LOI) test, cone calorimetry tests, scanning electron microscopy (SEM) and compressive strength tests. The results showed that an efficient ternary flame retardant system, DMMP/EG/MAPP, for rigid polyurethane foam was constructed. When the ratio of DMMP/EG/MAPP was 4/12/4, the cell size of RPUF composite was the most homogeneous, and the LOI value of RPUF composite reached 31.9%. The peak heat release and total smoke release value decreased to 97 kW/m2 and 347 m2/m2, respectively. The RPUF composites with 4%DMMP/12%EG/4%MAPP exhibited the best flame retardant property because DMMP/EG/MAPP played great free radical quenching effect in the gas phase by releasing the PO· and PO2· free radicals during the whole combustion process. Meanwhile, the compact char layer with "connected worm‐like" structure exerted barrier effect in the condensed phase. [ABSTRACT FROM AUTHOR]

Double emulsions have great potential application in many fields. Although many companies and research institutions have developed various strategies for forming double emulsions, production and stability are not straightforward. Meanwhile, none of the well-organized simple device and scalable technique was available to form highly monodispersed double emulsions. Herein, we present a one-step strategy to produce highly monodisperse double emulsion via assembled micro-cross device. This device has a lot of advantages, such as easy assembly/disassembly and high repeatability. High-throughput is also easily achievable for its high-pressure capacity. Moreover, we systematically studied the effects of the three flow rates on the size and structure of the double emulsions. A mathematical model has been developed to predict the inner and outer droplets size of the double emulsion. We prepared the flame-retardant microcapsules with a dimethyl methylphosphonate (DMMP) inner core and an ultraviolet-curable polysiloxane shell. We hope that this assembled micro-cross device can be employed extensively in the area of microfluidics. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new strategy for the sensitive and specific detections of dimethyl methylphosphonate (DMMP), as a simulant of nerve agent Sarin. Our silicon nanowire based sensor is modified with carboxyphenylboronic acid (CPBA) to demonstrate great efficiency. The response time is less than 100 seconds to recognize the DMMP, which is a key ability for on-site monitoring. The sensor exhibits a good reversibility during the repeated measurements between DMMP vapor and air. The sensor still performs well after being exposed in high concentration of DMMP vapor with excellent recovery for 3 times. The sensor is demonstrated to have a linear behavior in detecting DMMP within the concentration of 13~65 ppm in gaseous phase with the limit of detection (LOD) of 100 ppb. It is expected that the proposed sensor enables the testing system accurate, rapid, sensitive and reversible for on-site detection of nerve agents in the future. [ABSTRACT FROM AUTHOR]

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Wood is prone to fire attack making its application restricted as building material. The current study aims to evaluate the effect of double step chemical modification on Pinus radiata using Dimethyl Methyl phosphonate with Propylene oxide and Maleic anhydride. Wood samples were modified by single step using Propylene oxide (PO) or Maleic anhydride (MA) and the double-step modification comprised firstly of pressure treatment with Dimethyl Methyl phosphonate (DMMP) followed by chemical modification using Propylene oxide (PD) or Maleic anhydride (MD). Thermal property was studied using Thermo Gravimetric Analysis (TGA) and Derivative Thermogravimetric (DTG). The chemical modification resulted in better thermal stability of wood than control wood. Among treatments PD showed best fire retardancy property with maximum weight loss at 367°C with 18.2% residual mass. The preliminary study indicates that double step modification improved the thermal property increasing the temperature for maximum weight loss and residual mass comprising of char. [ABSTRACT FROM AUTHOR]

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A series of 2,2-disubstituted 8-azachromanones, including spirocyclic compounds, have been synthesized via Horner–Wadsworth– Emmons reaction. Dimethyl methylphosphonate was acylated with methyl 2-methoxypyridine-3-carboxylate to afford the key intermediate – dimethyl [2-(2-methoxypyridin-3-yl)-2-oxoethyl]phosphonate. Further reaction of this phosphonate and ketones followed by treatment with TMSCl–NaI provided the target 8-azachromanones. Scope and limitations of the developed synthetic method have been investigated. [ABSTRACT FROM AUTHOR]

In the present work, we report the use of regioregular poly(3-hexyltiophene) polymer (RR-P3HT) as a potential light-activated material for sensing the chemical nerve agent simulant dimethyl methylphosphonate (DMMP). The electrical response of thick films of RR-P3HT, deposited by spray-coating method onto a porous laminate substrate at room temperature, to DMMP vapours was investigated. The studied material was activated by light-emitting diodes that emitted light of different wavelengths. The sensing properties of RR-P3HT are considerably enhanced upon exposure to blue and yellow light. However, excitation by the low wavelength light (blue) caused degeneration of the material, resulting in lowered stability. In the case of the yellow light, degeneration was much slower and the limit of detection was 0.4 ppm. The studied material exhibited high selectivity, as it did not respond to 6 ppm of acetone and methanol vapours. [ABSTRACT FROM AUTHOR]