草酸酯

This paper focuses on dimethyl oxalate and conducts the following research based on the analysis of the hazards in the synthesis process of dimethyl oxalate and the development of a safety evaluation system: (1) It mainly introduces the process flow for synthesizing dimethyl oxalate. (2) The safety risk matrix method and HAZOP analysis are used to conduct hazard analyses at each process node of the dimethyl oxalate synthesis process. (3) Aspen is used to achieve steady-state simulation of the dimethyl oxalate synthesis process.

Abstract In this study, we reported the design, synthesis, and comprehensive evaluation of a series of nitro carbazole‐based oxime photoinitiators (OPIs, OP1: oxime oxalate, OP2: oxime glyoxylate), as a series of efficient Type I photoinitiators (PIs) for the free radical photopolymerization (FRP) of trimethylolpropane triacrylate (TMPTA) and ethoxylated trimethylolpropane triacrylate (ETPTA) under blue light‐emitting diodes and sunlight irradiation. Computational molecular modeling was employed to predict the effect of OPIs structures on the photoinitiation properties. The predictions suggest that OP1 had a higher propensity for decarboxylation and therefore a better photoinitiation behavior. Compared to OP2, OP3, and commercial benchmark photoinitiator TPO, OP1 exhibits exceptional photoinitiation performance when exposed to LED@405 nm, LED@450 nm, and sunlight. OP1 undergoes decarboxylation to efficiently produce CO2 and free radicals, thereby initiating the photopolymerization reaction. Remarkably, OP1 is successfully applied in 3D printing, producing complete morphology with high‐resolution structure, showcasing its potential for advanced manufacturing applications. The photochemical mechanism of OPIs is comprehensively elucidated using the monitoring of the CO2, steady state photolysis, UV–vis absorption spectroscopy, fluorescence spectroscopy, and electron spin resonance techniques. These experimental investigations are supported by data OP1 from the molecular modelling carried out. Additionally, thermal polymerization shows that OP1 had a high thermal initiation capability, and the composites are successfully prepared together with carbon fibers. The cytotoxicity of the synthesized oxime oxalate and TPO on human umbilical vein endothelial cells (HUVECs) results in a lower cytotoxicity for the oxalate than for TPO. Therefore, OP1, which has never been reported before, can be used as a highly efficient and low cytotoxic dual photo/thermal initiator. This research not only provides theoretical and practical insights into the design and development of new efficient Type I PIs, but also opens up new perspectives for curing applications that require scalability, cost‐effectiveness, environmental sustainability, and green chemistry.

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A catalyst with the active component Cu loaded onto the carrier activated carbon was prepared, and metal Ca was introduced into the catalyst to modify it. This catalyst was used in the hydrogenation reaction of dimethyl oxalate, and the reaction kinetics was studied. The kinetic experiments were carried out in a fixed bed reactor with a reaction temperature varying from 483 K to 513 K, reaction pressure varying from 1.5 Mpa to 2.5 Mpa, and the weight hourly space velocity of dimethyl oxalate varying from 0.435 h−1 to 0.726 h−1. Eight possible dynamic models were proposed, the optimal model was selected, and the parameters of the optimal model were calculated using MATLAB. The results showed that dimethyl oxalate adsorbed on the active site by dissociation adsorption, and the dissociation adsorption of ester was the rate-controlling step. The parameters of the model were consistent with thermodynamics and statistical analysis, further proving that the model has good forecasting performance.

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Perovskite surfaces exhibit defect densities ∼100× higher than the bulk, making interfacial recombination and instability critical challenges for perovskite solar cells (PSCs). Here, we introduced bis(2,4,5-trichloro-6-carbopentoxyphenyl) oxalate (BTCPPO), a novel oxalate derivative, at the perovskite/hole transport layer (HTL) interface. BTCPPO features a symmetric structure comprising a central oxalate group bridged to two phenyl rings with pentoxy ester tails, which enables secondary modification-induced local recrystallization in the upper perovskite film. Through chelation between its oxygen-containing groups and uncoordinated Pb2+, BTCPPO reduces grain boundaries (GBs), enhances crystallinity, and passivates interfacial/GB defects, thereby prolonging charge-carrier lifetimes and suppressing nonradiative recombination. Additionally, BTCPPO fills GB voids, creating a smoother, superhydrophobic surface that impedes moisture/oxygen ingress while optimizing energy level alignment for efficient hole extraction. The resulting PSCs achieve a champion efficiency of 25.62% (negligible hysteresis) and retain ∼90% of their initial PCE after 3800 h in ambient conditions (∼30% RH), alongside exceptional thermal and illumination stability.

Achieving simultaneous high activity, selectivity, and stability in ester hydrogenation remains a persistent challenge, largely due to the competitive adsorption of reactants at active sites. Here, we introduce an inverse NiOx-Ag interface as a general design platform to spatially decouple the activation of H2 and ester, exemplified with dimethyl oxalate (DMO). The catalyst (Ag-Ni/SiO2), synthesized via controlled partial reduction of Ni phyllosilicate followed by Ag deposition, features electron-rich Ag sites and electron-deficient interfacial Ni sites arising from interfacial electron transfer. Comprehensive characterizations reveal abundant NiOx-Ag interfaces with modified coordination and electronic structures. In situ Fourier-transform infrared spectroscopy, temperature programmed desorption/surface reaction, and H2-D2 isotope exchange experiments demonstrate that H2 is preferentially dissociated at Ag sites, while DMO adsorbs and activates on NiOx sites, effectively mitigating competitive adsorption. Theoretical calculations confirm the cooperative nature of the interface, showing low barriers for H2 dissociation and favorable desorption energetics for methyl glycolate (MG), suppressing over-hydrogenation. Accordingly, the Ag-Ni/SiO2 catalyst delivers a turnover frequency of 944.4 h-1 with ∼99% selectivity to MG over 500 h of continuous operation, among the highest reported for DMO hydrogenation. This work establishes interfacial inversion engineering as a versatile approach to optimize site complementarity in multi-step catalytic transformations.

In this work, the effect of alkaline earth metal modification on the catalytic performance of activated carbon supported Cu was investigated. The experimental results showed that the introduction of Ca and Sr improved the selectivity of methyl glycolate (MG) during hydrogenation of dimethyl oxalate (DMO) in gas phase. The optimal loading amount of Ca was 0.1 wt%, and under the optimal conditions (temperature 240 °C, pressure 2 MPa, hydrogen–ester ratio of 80, feedstock 15% DMO methanol solution, and WLHSVDMO = 0.9 h−1) the selectivity of MG was as high as 94%, and the conversion of DMO was 97%. The optimal loading of Sr was 0.2 wt% with MG selectivity up to 89% and DMO conversion of 98%. The results of catalyst characterization showed that both Ca and Sr modifications were beneficial to further reduce the particle size of Cu, improve the dispersion of Cu, increase the basicity of the catalyst, and improve the stable presence of Cu+ during the reaction process. Cu+ was beneficial to the stabilization of the MG species, in which Cu+ accounted for more in the Ca-modified catalysts Cu+/(Cu+ + Cu0) = 0.65, and in the Sr-modified ones Cu+/(Cu+ + Cu0) = 0.51. Therefore, both Ca and Sr modified catalysts showed improvement in the selectivity of MG.

No abstract available

The direct esterification of CO involves processes using CO as the starting material and ester chemicals as products. Dimethyl oxalate (DMO) and dimethyl carbonate (DMC) are two different products of the direct CO esterification reaction. However, the effective control of the reaction pathway and direct synthesis of DMO and DMC are challenging. In this review, we summarize the recent research progress on the direct esterification of CO to DMO/DMC and reveal the functional motifs responsible for the catalytic selectivity. Firstly, we discuss the microstructure of catalysts for the direct esterification of CO to DMO and DMC, including the valence state and the aggregate state of Pd. Then, the influence of characteristics of the support on the selectivity is analyzed. Importantly, the aggregate state of the active component, Pd is deemed as a vital functional motif for catalytic selectivity. The isolated Pd is conducive for the formation of DMC, while the aggregated Pd is beneficial for the formation of DMO. This review will provide rational guidance for the direct esterification of CO to DMO and DMC.

Phospholipid membranes are ubiquitous components of cells involved in physiological processes; thus, knowledge regarding their interactions with other molecules, including tocopherol ester derivatives, is of great importance. The surface pressure–area isotherms of pure α-tocopherol (Toc) and its derivatives (oxalate (OT), malonate (MT), succinate (ST), and carbo analog (CT)) were studied in Langmuir monolayers in order to evaluate phase formation, compressibility, packing, and ordering. The isotherms and compressibility results indicate that, under pressure, the ester derivatives and CT are able to form two-dimensional liquid-condensed (LC) ordered structures with collapse pressures ranging from 27 mN/m for CT to 44 mN/m for OT. Next, the effect of length of ester moiety on the surface behavior of DPPC/Toc derivatives’ binary monolayers at air–water interface was investigated. The average molecular area, elastic modulus, compressibility, and miscibility were calculated as a function of molar fraction of derivatives. Increasing the presence of Toc derivatives in DPPC monolayer induces expansion of isotherms, increased monolayer elasticity, interrupted packing, and lowered ordering in monolayer, leading to its fluidization. Decreasing collapse pressure with increasing molar ratio of derivatives indicates on the miscibility of Toc esters in DPPC monolayer. The interactions between components were analyzed using additivity rule and thermodynamic calculations of excess and total Gibbs energy of mixing. Calculated excess area and Gibbs energy indicated repulsion between components, confirming their partial mixing. In summary, the mechanism of the observed phenomena is mainly connected with interactions of ionized carboxyl groups of ester moieties with DPPC headgroup moieties where formed conformations perturb alignment of acyl chains, resulting in increasing mean area per molecule, leading to disordering and fluidization of mixed monolayer.

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α-Tocopherol oxalate (TO), a tocopherol ester derivative, was investigated for its effect on the structural changes of fully hydrated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes, as a function of concentration and temperature, by applying differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and DPH fluorescence anisotropy methods. The DSC and DPH anisotropy data indicated that TO embedded into DPPC membrane lowered the enthalpy (ΔHm) and temperature (Tm) of the main phase transition as well its cooperativity. Fluidization of the membrane at a lowered temperature was accompanied by formation of mixed structures of tocopherol-enriched domains. SAXS studies showed the formation of various ordered structures in DPPC gel-phase during incorporation of TO into the bilayer, as evidenced by the existence of lamellar phases with repeat distances (d) of 6.13 and 6.87 nm, assigned to TO-enriched domains and a lamellar, liquid-ordered DPPC phase with d = 8.45 nm at increasing TO concentrations with lowering and broadening of the Bragg peaks, and diffuse scattering, characteristic of a fluid Lα phase, were observed. In DPPC fluid-phase, the increasing presence of TO at low concentrations resulted in the appearance of a liquid-ordered phase with repeat d = 6.9 nm coexistent with a lamellar structure with d = 9.2 nm, assigned to liquid-disordered structures. An increasing repeat distance observed with raising the TO amount in the DPPC bilayer evolved from an increasing interlamellar water layer of increasing thickness. Presence of TO facilitated penetration of water molecules into the acyl chain region which decreased van der Waals interactions in the bilayer. The DSC, SAXS, and fluorescence anisotropy data established that TO exhibited pronounced disruptive activity in DPPC membranes compared to α-tocopherol. The driving force of the observed action was attributed to electrostatic and dipole interactions of the acidic moiety with the polar head group of phospholipids in the interface region of the bilayer.

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This study explored a facile method for converting macadamia nutshells into bio-based nanomaterials, including cellulose nanofibers (CNFs) and lignin nanoparticles (LNPs), through deep eutectic solvent (DES) pretreatment coupled with a nanofabrication strategy. Comparisons of the physicochemical, morphological, and structural properties of the CNF and LNPs produced through acidic choline chloride/oxalic acid dihydrate (ACDES) and alkaline K2CO3/glycerol DES (ALDES) pretreatments were conducted using SEM, TEM, FTIR, XRD, TGA, GPC and 2D NMR. The CNFs obtained from ACDES pretreatment (ACCNFs) exhibited uniform and long filament-like structures with shorter whisker-like nanocrystals. Conversely, the CNFs produced with the ALDES pretreatment (ALCNFs) displayed irregular aggregates and nanofibril bundles. Additionally, the ACCNFs demonstrated higher crystallinity and contained small amounts of the oxalate half-ester compare to ALCNFs. During ACDES pretreatment, a large proportion of β-O-4, β-5, and β-β linkages in lignin disrupted and re-condensed to form lignin substructures, resulting in the assembly of cluster-like lignin nanoparticles pretreated with ACDES (ACLNP) aggregates. In contrast, lignin nanoparticles pretreated with ALDES (ALLNP) exhibited uniform nanospherical shapes because of the preservation of β linkages in lignin during the ALDES pretreatment. This work not only broadens the fabrication strategies for CNF and LNPs but also offered a promising approach for the valorization of lignocellulosic agricultural wastes.

Curcumin, a natural bioactive polyphenol with diverse molecular targets, is well known for its anti‐oxidation and anti‐inflammatory potential. However, curcumin exhibits low solubility (<1 µg mL−1), poor tissue‐targeting ability, and rapid oxidative degradation, resulting in poor bioavailability and stability for inflammatory therapy. Here, poly(diselenide‐oxalate‐curcumin) nanoparticle (SeOC‐NP) with dual‐reactive oxygen species (ROS) sensitive chemical moieties (diselenide and peroxalate ester bonds) is fabricated by a one‐step synthetic strategy. The results confirmed that dual‐ROS sensitive chemical moieties endowed SeOC‐NP with the ability of targeted delivery of curcumin and significantly suppress oxidative degradation of curcumin for high‐efficiency inflammatory therapy. In detail, the degradation amount of curcumin for SeOC is about 4‐fold lower than that of free curcumin in an oxidative microenvironment. As a result, SeOC‐NP significantly enhanced the antioxidant activity and anti‐inflammatory efficacy of curcumin in vitro analysis by scavenging intracellular ROS and suppressing the secretion of nitric oxide and pro‐inflammatory cytokines. In mouse colitis models, orally administered SeOC‐NP can remarkably alleviate the symptoms of IBD and maintain the homeostasis of gut microbiota. This work provided a simple and effective strategy to fabricate ROS‐responsive micellar and enhance the oxidation stability of medicine for precise therapeutic inflammation.

Antigen presentation is a critical driver of cytotoxic antitumor immunity and a limiting factor in mRNA vaccine efficacy. The overabundance of intracellular reactive oxygen species, such as hydrogen peroxide (H2O2), generated during LNP@mRNA transfection severely compromises the mRNA translation efficiency, and the resultant lipid peroxidation further disrupts antigen-presenting pathways. Herein, we screen 96 antioxidants and identify vitamin E as a potentiator of LNP to drastically promote the translation efficiency of mRNA and antigen presentation by dendritic cells. We design and synthesize a vitamin E-modified ionizable lipid (cEIL) linked by an oxalate ester, which is susceptible to cleavage by H2O2 to modulate the intracellular redox microenvironment. Incorporation of cEIL as a chaperone within LNP (ceLNP) enables adaptive vitamin E release upon encountering elevated H2O2 during transfection, which expedites the restoration of intracellular redox homeostasis, thus reinforcing the translation efficiency and mitigating lipoperoxidation to bolster the antigen presentation through the HSP70-mediated MHC I pathway. mRNA vaccines fabricated from ceLNP elicit strong antitumor immune responses to suppress tumor growth and inhibit tumor metastasis across multiple models, including melanoma, colon cancer, and neoantigen-expressing tumors, both as standalone treatments and in combination with immunotherapy or chemotherapy. This vitamin E-chaperoned delivery system holds immense promise as a universal platform for the development of next-generation mRNA vaccines in cancer immunotherapy with potent efficacy and safety.

CO esterification involves processes using CO as the starting material and ester chemicals as products. Methyl formate, dimethyl oxalate and dimethyl carbonate are the main products. Traditional Pd nanoparticles (PdNPs)...

Lipid droplets are dynamic organelles involved in lipid metabolism and various metabolic disorders. Herein, we report the design and synthesis of a novel amphiphilic polymer based on 18β-glycyrrhetinic acid (GA). GA was chemically conjugated to polyethylene glycol (PEG) and further functionalized with a lipid droplet-targeting fluorescent probe D via an oxalate ester bond, then self-assembly yielding PGOD nanoplatform. The PGOD were characterized by a uniform size of 135.6 ± 5.4 nm, a polydispersity index (PDI) of 0.23 ± 0.02, and a zeta potential of 11.81 ± 1.44 mV. These nanoparticles exhibited dual fluorescence properties driven by aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT). This work provided that nanoplatform could specifically label lipid droplets to monitor the progress of lipid accumulation, alleviating oxidative stress, and at the same time promote the decomposition of lipid droplets by activating lipophagy, significantly improving the lipid metabolism disorder in the liver of NAFLD model mice.

In continuation of our work on the synthesis and study of new properties of 4-substituted 3-aminopyridin-2-(1H)-ones, we carried out the synthesis and subsequent cyclization of the corresponding oxalyl amides. The aminolysis reaction of diethyl oxalate with 3-aminopyridin-2-(1H)-ones was carried out by boiling without solvent at a temperature of 150 °C. In this case, intermediate oxalic acid monoamides with the remainder of the ester group were also recorded and separately identified. It was shown that under the action of phosphorus oxychloride the synthesized oxalic acid diamides undergo fairly smooth intramolecular cyclization into symmetrical bis-derivatives of oxazolo[5,4-b]pyridine. The photoluminescent properties of our newly obtained oxazolo[5,4-b]pyridine derivatives 5-8a-c and 2,2'-bisoxazolo[5,4-b]pyridines 4a-c were studied, including such parameters as maximum absorption (λ), molar absorption coefficient (ε), Stokes shift, and quantum yield. All compounds were found to luminesce with a bluish-blue color and exhibit maximum absorption wavelengths in the range of 299–333 nm (in acetonitrile) and 281–317 nm (in toluene), which is associated with the π–π* electron transition. A fairly large Stokes shift (83–128 nm) is observed for all compounds. It was also found that the presence of a carboxyl linker at the C-2 position of compounds 5-8a-c does not significantly affect the shift of the absorption band maxima and other spectral characteristics of the molecules. It should be noted that symmetrical conjugated 2,2'-bisoxazolo[5,4-b]pyridines 4a-c, featuring two oxazolo[5,4-b]pyridine rings, exhibit fairly high quantum yield values (φ ≈ 0.70–0.82) compared to the known standard quinine sulfate (φ ≈ 0.55), allowing their potential application as effective fluorophores.

This work investigates the chemical modification of food-grade gum arabic (GA) using various polycarboxylic acids (citric, adipic, succinic, and oxalic) to enhance its functional properties for advanced applications. The esterification reaction was confirmed through a combination of elemental analysis and FTIR spectroscopy, which indicated the successful incorporation of carboxyl and ester groups into the polysaccharide structure. X-ray diffraction analysis revealed a further amorphization of the modified samples, confirming structural changes. Gel permeation chromatography showed a significant increase in the average molecular weight (Mw) and polydispersity of the derivatives, indicating both cross-linking and chain extension reactions. Atomic force microscopy demonstrated the formation of homogeneous, defect-free films consisting of spherical particles agglomerated into a continuous matrix. Thermal analysis (TGA/DSC) revealed modified thermal degradation patterns and showed that the oxalate derivative (GA-OxA) exhibited the highest thermal stability with a residual mass of 80.73% at 500 °C and the maximum activation energy for decomposition (295 kJ/mol). The results demonstrate the successful synthesis of tailored gum arabic derivatives with improved thermal properties and altered solubility, making them promising materials for applications in food packaging, edible coatings, and as carriers for controlled delivery systems.

The application of solid polymer electrolytes (SPEs) in all-solid-state(ASS) batteries is hindered by lower Li+-conductivity and narrower electrochemical window. Here, three families of ester-based F-modified SPEs of poly-carbonate (PCE), poly-oxalate (POE) and poly-malonate (PME) were investigated. The Li+-conductivity of these SPEs prepared from pentanediol are all higher than the counterparts made of butanediol, owing to the enhanced asymmetry and flexibility. Because of stronger chelating coordination with Li+, the Li+-conductivity of PME and POE is around 10 and 5 times of PCE. The trifluoroacetyl-units are observed more effective than -O-CH2-CF2-CF2-CH2-O- during the in-situ passivation of Li-metal. Using trifluoroacetyl terminated POE and PCE as SPE, the interfaces with Li-metal and high-voltage-cathode are stabilized simultaneously, endowing stable cycling of ASS Li/LiNi0.6Co0.2Mn0.2O2 (NCM622) cells. Owing to an enol isomerization of malonate, the cycling stability of Li/PME/NCM622 is deteriorated, which is recovered with the introduce of dimethyl-group in malonate and the suppression of enol isomerization. The coordinating capability with Li+, molecular asymmetry and existing modes of elemental F, are all critical for the molecular design of SPEs.

Metal-support interaction is one of the most important parameters in controlling the catalysis of supported metal catalysts. Silica, a widely used oxide support, has been rarely reported as an effective support to create active metal-support interfaces for promoting catalysis. In this work, by coating Cu microparticles with mesoporous SiO2, we discover that Cu/SiO2 interface creates an exceptional effect to promote catalytic hydrogenation of esters. Both computational and experimental studies reveal that Cu–Hδ− and SiO–Hδ+ species would be formed at the Cu–O–SiOx interface upon H2 dissociation, thus promoting the ester hydrogenation by stablizing the transition states. Based on the proposed catalytic mechanism, encapsulting copper phyllosilicate nanotubes with mesoporous silica followed by hydrogen reduction is developed as an effective method to create a practical Cu nanocatalyst with abundant Cu-O-SiOx interfaces. The catalyst exhibits the best performance in the hydrogenation of dimethyl oxalate to ethylene glycol among all reported Cu catalysts. Metal-support interaction plays an important role in heterogeneous catalysis, but silica has been rarely reported as an effective support to create active metal-support interfaces for promoting catalytic reactions. Here, the authors discover that Cu/SiO2 interface creates an exceptional effect to promote catalytic hydrogenation of esters.

Oxidative degradation of the pathogenic amyloid-β-peptide (Aβ) aggregation is an effective and promising method to treat Alzheimer's disease under light irradiation. However, the limited penetration of external light sources into deep tissues has hindered the development of this treatment. Therefore, we have designed an unprecedented chemiluminescence-initiated photodynamic therapy system to replace external laser irradiation, primarily composed of d-glucose-based polyoxalate (G-poly(oxalate)), the novel photosensitizer (BD-Se-QM), and bis [2,4,5-trichloro-6-(pentoxy-carbonyl) phenyl] ester. BD-Se-QM possesses excellent singlet oxygen (1O2) generation efficiency and the ability to photooxidize Aβ1-42 aggregates under white light. G-poly(oxalate) not only helps the nanosystem to cross the blood-brain barrier but also has sufficient oxalate ester groups to significantly enhance the efficiency of chemiluminescence resonance energy transfer. The oxalate ester groups in BD-Se-QM/NPs can chemically react with H2O2 to produce high-energy intermediates that activate BD-Se-QM, which can generate 1O2 to inhibit Aβ1-42 aggregates and also promote microglial uptake of Aβ1-42, reducing the Aβ1-42-induced neurotoxicity. The chemically stimulated nanoplatform not only solves the drug delivery problem but also eliminates the need for external light sources. We anticipate that this chemically excited nanosystem could also be used for targeted delivery of other small molecule drugs.

No abstract available

The results of a study of the physicochemical properties of N'-tosylhydrazide oxalic acid (ETH) ethyl ester are presented. The solubility of the reagent in ethanol, 0.1 mol/l KOH solution, toluene, chloroform, hexane, and water was studied by spectrophotometry, refractometry, and gravimetry. Based on the results obtained, it was shown that ETG can be used in flotation and extraction processes. Acid-base equilibria in reagent solutions were studied by spectrophotometric method. The obtained values of acid dissociation constants (pKa1=7.56 ± 0.14; pKa2=13.48 ± 0.22) prove that ETG is a weak dibasic acid. The hydrolytic stability of the reagent was studied by the spectrophotometric method. The results of the study showed that ETG solutions are quite stable in time in alkaline media: the degree of hydrolysis for two hours is 4.77%. The surface activity of the reagent was determined by the stalagmometric method. ETG has been found to be a surfactant.

Based on monoethyl esters of oxalic acid amides obtained earlier by the reaction of arylcyclopentylmethyl-, aryltetrahydropyranylmethyl-, isochromanyl-1-methyl-, (1,4-benzodioxan-2-yl)-methyl- and 1-(1,4-benzodioxan-2- yl)-ethyl amines with oxalic acid diethyl ester, by the action of various primary amines, target substituted oxalic acid diamides were synthesized. For the synthesis of diamides containing anilide fragments, ethyl esters of substituted oxalic acid N-arylamides were used, which were reacted with the above arylalkyl- and heterylalkylamines. The antioxidant activity of the synthesized compounds has been studied. Թրթնջկաթթվի ամիդների մոնոէթիլային մի շարք եթերներ, որոնք ստացվել են ավելի վաղ արիլցիկլոպենտիլմեթիլ-, արիլտետրահիդրոպիրանիլմեթիլ-, իզոխրոմանիլմեթիլ-, (1,4-բենզոդիօքսան-2-իլ)-մեթիլ- և 1-(1,4-բենզոդիօքսան-2-իլ)-էթիլամինների և դիէթիլօքսալատի ռեակցիայի արդյունքում, փոխազդեցության մեջ են դրվել տարբեր առաջնային ամինների հետ՝ առաջացնելով նոր համապատասխան դիամիդներ: Սինթեզվել են տեղակալված անիլիդների ֆրագմենտներ պարունակող օքսալաթթվի դիամիդներ անիլիդոէսթերների և վերը նշված արիլալկիլ- և հետերիլալկիլամինների փոխազդեցությամբ: Հետազոտվել են սինթեզված միացությունների հակաօքսիդանտ հատկությունները: На основе моноэтиловых эфиров амидов щавелевой кислоты, полученных ранее реакцией арилциклопентилметил-, арилтетрагидропиранилметил-, изохроманил-1-метил-, (1,4-бензодиоксан-2-ил)-метил- и 1-(1,4-бензодиоксан-2-ил)-этил аминов с диэтиловым эфиром щавелевой кислоты, действием разнообразных пер-вичных аминов синтезированы целевые замещенные диамиды щавелевой кис-лоты. Для синтеза диамидов, содержащих фрагменты анилидов, использованы этиловые эфиры замещенных N-ариламидов щавелевой кислоты, которые поставлены во взаимодействие с вышеуказанными арилалкил- и гетерилал-киламинами. Исследована антиоксидантная активность синтезированных соединений.

No abstract available

The suitability of oxalic acid as a crosslinker of polyvinyl alcohol (PVA) is the focus of study of the present paper. Oxalic acid concentration was varied from 3–70% (w/w with respect to polymer) and curing was carried out at various temperatures (100–140 °C) for a range of time periods (20–120 minutes). The optimum curative dose and curing conditions were evaluated through systematic swelling studies (% swelling, gel content, swelling ratio and molecular weight between the crosslinks) of the oxalic acid-treated PVA films, both in hot and cold water. Thermogravimetric analysis showed higher heat stability of oxalic acid crosslinked PVA film compared with heat-treated and virgin PVA. The shift in glass transition temperature (from that of virgin PVA 86 °C) to a higher value for heat-treated and oxalic acid-treated PVA was more prominent for the former than the later. Crosslinking enhanced the Young's modulus and IR spectra indicate the formation of ester carbonyl group in crosslinked PVA.

The study presents a cutting-edge, sustainable approach for the high-yield production (59-62 %) of carboxyl-functionalized cellulose nanocrystals (CNCs) with impressive aspect ratio (20.65 ± 0.74 nm), high crystallinity (77-81 %), outstanding thermal stability (290 °C-343 °C) and varying degrees of functionalization. This innovative method harnesses the synergistic power of mild organic acid hydrolysis (10 %) and steam explosion, employing eco-friendly acids such as acetic, citric, malic, tartaric, and oxalic. These acids drive efficient esterification, as evidenced by zeta potential values (-16 mV to -34 mV) and the presence of ester carbonyl peaks in IR spectroscopy (1730 cm-1). This functionalization enhances the CNCs' colloidal stability by anchoring carboxyl functionalities, which serve as reactive sites for subsequent modifications to tune their hydrophilic or hydrophobic properties -making them versatile candidates for next-generation applications in packaging, biomedical technologies, and edible coatings. Additionally, the successful recovery of the organic acids further enhances the sustainability of this process. Rooted in the principles of green chemistry, this process ensures atom economy, reduced hazardous chemicals, and valorization of Elettaria cardamomum agromass, offering a transformative step towards a circular economy.

A group of acyclic sesquiterpenoids, that form the Juvenile hormone is crucial in the developmental physiology of insects. Aedes aegypti is crucial in spreading fatal diseases such as dengue, and dengue hemorrhagic fever. The mosquito undergoes several stages of development, from the egg to the adult stage, utilizing its innate immunity system and juvenile hormone proteins. Thus, targeting the juvenile hormone-binding proteins can potentially inhibit the developmental stages of the mosquito. The mosquito juvenile hormone binding protein (mJHBP) of Aedes aegypti was obtained from the RCSB (PDB). The study identified that Talaromyces islandicus and Bacillus velezensis produced secondary metabolites that act as efficient ligand complexes. The secondary metabolites were procured from PubChem and docked to the binding sites of mJHBP. Among the 26 listed ligand compounds, oxalic acid, decyl 3,5-difluorophenyl ester, oxalic acid 3,5-difluorophenyl undecyl ester, and p-octylacetophenone were found to have higher binding affinity, marking their efficiency in inhibiting the protein. Normal mode analysis studies were performed using iMODs to analyze the B-factor, variance, covariance, and Eigenvalues of the docked protein-ligand complexes. The Absorption, Distribution, Metabolism and Excretion (ADME) properties of the efficient ligand molecules were analyzed using the Swiss ADME tool to segregate potential drug candidates. Targeting the mJHBP complex using the microbial metabolite ligand molecules can inhibit the development of the mosquitoes. The work enlightens the futuristic development of potential candidates in the production of insecticides. The literature confirms it is the first of its type to utilize microbial bio compounds as ligands targeting the mJHB protein complex.  

The antivenom potential of Andrographis echioides (A. echioides), a traditional medicinal herb, was investigated using a comprehensive in silico approach to address the limitations of conventional antivenoms against Russell’s viper envenomation. This study aimed to conduct virtual screening and molecular dynamics (MD) studies of flavonoid compounds from A. echioides to explore their potential as antivenom agents. Gas chromatography-mass spectrometry (GC–MS) analysis identified 84 bioactive phytochemicals in the leaf extracts. The selected flavonoid constituents were evaluated for their predicted inhibitory potential against venom-associated enzymes using molecular docking with the iGEMDOCK software. The target proteins included metalloproteinase (PDB ID: 2E3X), serine proteinase (PDB ID: 3S9A), and human pancreatic phospholipase A2 (PDB ID: 6Q42). Among the screened compounds, decanoic acid (− 93.7429 kcal/mol), oxalic acid 6-ethyloct-3-yl isohexyl ester (− 91.6448 kcal/mol), and oxalic acid 6-ethyloct-3-yl hexyl ester (− 85.7934 kcal/mol) exhibited the highest binding affinities to the target protein and compared them with the standard compound. Drug-likeness analysis confirmed the favorable pharmacokinetic properties of compounds. MD simulations spanning 100 ns revealed stable binding interactions, consistent RMSD values, favorable hydrogen bonding patterns, and stable structural dynamics. This is the first study to report the antivenom potential of bioactive compounds from this species using computational methods. These computational insights suggest that flavonoid constituents derived from A. echioides may possess promising binding and predicted inhibitory activities against key venom enzymes, warranting further investigation as potential natural antivenom agents.

The use of medicinal plants as complementary therapies has lately grown in popularity. The aim of this study was to determine the chemical composition of the aqueous root extract of Gnetum africanum using GC-MS and GC-FID analysis. Fresh roots of G. africanum Welw used in this study were collected, cut into pieces, washed and air-dried. The dried plant materials were ground into powder and kept in an airtight container. GC-MS analysis of the aqueous root extract revealed 20 bioactive compounds with the following being most abundant 2,3-Butanediol as the predominant phytochemical at 46.02%, followed by Benzene, 1,4-dichloro (3.57%) and Oxalic acid, allyl octadecyl ester (3.45%). The quantitative GC-FID determination of the phytochemicals of Gnetum africanum aqueous root extract presented common phytochemicals such as, alkaloids, flavonoids, steroids, phenols and glycosides. Phytochemicals in higher proportions include; sapogenin (26.2645 µg/ml), anthocyanins (17.4986 µg/ml), cyanogenic glycosides (15.3616 µg/ml), kaempferol (13.7621 µg/ml) and flavan-3-ol (13.0446 µg/ml). It has been discovered that the root of Gnetum africanum contains an array of phytocompounds with a variety of therapeutic properties.

Ammonium oxathioamidate (1) was synthesised by the reaction between O-ethyl-thioxamate (oxalic acid-1-amide-2-O-ethyl ester) and ammonium hydrogen carbonate in water solution. Compound 1 was fully characterised by both microanalytical (elemental analysis, melting point determination) and spectroscopic means (FT-IR and NMR spectroscopy). Crystals suitable for single-crystal X-ray diffraction were isolated by slow evaporation of an ethanol solution of the compound. The analysis of the crystal packing reveals the prominent role exerted by intermolecular hydrogen bonding (HB) and chalcogen bonding (ChB) interactions.

Heliotropium bacciferum plant is very important and has been used for medicinal values since ancient times. The present study deals with the extraction of essential oil (0.14 w/w) of this plant and its GC-MS analysis, anti-inflammatory, and anti-bacterial activities evaluation. GC analysis of essential oil confirmed 76 compounds with 49 terpenes and oxygenated hydrocarbons. The main components of this essential oil are agarospirol (15.15 %), rosifoliol (9.41 %), elemol (8.96 %), tau.-cadinol (8.05 %), linalool (5.37 %), shyobunol (5.36 %) cyclohexylmethyl tridecyl ester of oxalic acid (4.74 %), respectively. The essential oil showed quite good anti-inflammatory activity while this oil indicated excellent anti-bacterial activity against 3 g-positive pathogenic bacteria (Bacillus subtilusATCC 6633, Entrococcus faecalis ATCC 29212, and Bacillus cereusATCC 11778). The essential oil of Heliotropium bacciferum showed great potential as an anti-inflammatory and anti-bacterial agent. Therefore, the reported extraction and GC-MS analysis methods are useful to extract the essential oil and determine the composition of other plants. The extracted essential oil may be used to treat several diseases.

The present study investigated the chemical constituents isolated from Azadirachta indica chloroform extract. The extraction of leaves was done using Soxhlet extraction apparatus. To isolate and identify the antibacterial fraction from Azadirachta indica chloroform extract, TLC-bioautography was carried out. Phenol 3,5-bis (1,1-dimethyl ethyl), Phthalic acid bis (7-methyloclyl), Dido decyl phthalates, Oxalic acid, allyl hexadecyl ester, and 2-Piperidinone, N-(4-bromo-n-butyl) were the five primary antibacterial chemicals identified by the GC-MS study. The findings of the FTIR study revealed the presence of functional groups C-H str, C=O str, and C=C str as well as alcohol and the carboxylate ion. While the 13C NMR data demonstrated the existence of carbonyl, aromatic carbon, quaternary carbon, olefinic carbon, and methyl group, and the 1H NMR results revealed the presence of aliphatic OH, methyl, aromatic OH, and olefinic proton. The phytoconstituents detected using GC-MS analysis showed a wide range of pharmacological properties, including antioxidant, antibacterial, antifungal, anti-inflammatory, and antimalarial effects. Thus, Azadirachta indica plant has a high concentration of medicinal phytoconstituents that can be used to make antimicrobial medications to fight against plant pathogenic bacteria.

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The large-scale synthesis of several kinds of monoalyl oxalates, which are half-esters of dialkyl oxalates, under practical and environmentally friendly conditions is described by applying the selective monohydrolysis reaction of symmetric diesters that we reported previously. The most suitable conditions were examined for the kinds of base, equivalent, cosolvent, and reaction time for large-scale production of five kinds of monoalkyl oxalate, monomethyl oxalate, monoethyl oxalate, monopropyl oxalate, monoisopropyl oxalate, and monobutyl oxalate, which are among the most versatile building blocks, but the commercial availabilities are limited. The conditions are mild, simple, and environmentally benign, and the half-esters were produced in high yields, exhibiting high purities in only a few hours without requiring special equipment. Therefore, the synthetic advantage of this reaction is anticipated.

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In this study, we developed a novel theranostic nanomedicine formulation that integrates multimodal imaging with controlled drug release in reactive oxygen species (ROS)-rich microenvironments. A fluorinated oxalate compound (FOC) was synthesized through a one-step condensation reaction between 1,1,1,3,3,3-hexafluoro-2-propanol and oxalyl chloride, characterized by 1H, 13C, and 1⁹F NMR spectroscopy. The FOC and luminophore-incorporated nanomedicine formulations reacted rapidly with hydrogen peroxide via the peroxyoxalate chemiluminescence (POCL) mechanism, producing strong chemiluminescence and inducing a notable 19-fold increase in ratiometric 1⁹F NMR signal upon conversion to fluorinated alcohol (FAH), demonstrating promising potential for high-contrast 1⁹F MRI in deep tissue. Following ROS stimulation, the chemical conversion from hydrophobic FOC to hydrophilic FAH led to the degradation of the nanomedicines, facilitating payload release. In vitro experiments with A-431 cancer cells under hypoxic conditions confirmed ROS-responsive drug release, evidenced by enhanced fluorescence from model luminophores. Additionally, doxorubicin-loaded FOC nanomedicines reduced cell viability to 32% under hypoxia while remaining non-toxic in normoxic conditions. These results indicate that FOC-based nanomedicine formulations provide a promising platform for combined chemiluminescence and 1⁹F MRI with targeted therapeutic efficacy in ROS-rich inflammatory and cancerous tissues.

This research studied the effect of solvent ratio on chemiluminescence widely applied in glow sticks using dichloromethane and ethyl acetate as solvents. The fluorescent solution, as a mixture of diphenyl oxalate solvent and fluorescent dye rhodamine B, was stimulated by a 405 nanometre laser for fluorescent spectrum measurement before the chemiluminescence experiment. The fluorescent solution concentration and solvent ratio were varied. For the chemiluminescence experiment, diphenyl oxalate was dissolved in the solvents and combined with rhodamine B that interacted with a mixture of hydrogen peroxide and acetonitrile, resulting in chemiluminescence. The duration and intensity of light were measured by a photodiode detector. Results revealed that the concentration and solvent ratio of the fluorescent solution impacted the fluorescent spectrum due to opacity and solubility. Increasing ethyl acetate and decreasing dichloromethane gave a longer duration of light. The intensity of light in some ratios alternated high and low. Light emitted for a long time at high intensity is suitable for applications. Solvent ratios at 3:7 and 5:5 (1:1) gave better results than the other samples.

Peroxyoxalate chemiluminescence (POCL) systems have received great attention due to their high quantum yield and the ability to emit a wide-range colors by the utilizing different fluorophores. In this research, Pyronin Y (PY) was first introduced as the fluorophore for a POCL system. Our results indicated that the reaction of (2, 4-dinitroophenyl) oxalate (DNPO) with hydrogen peroxide (H2O2) catalyzed by sodium salicylate (SS) could transfer energy to Pyronin Y via the formation of the dioxetanedione intermediate and emit orange-red light. The relationships between chemiluminescence (CL) intensity and the concentrations of DNPO, fluorophore, H2O2, and the catalyst were investigated. Moreover, the analytical utilization of the new CL system was evaluated by detecting a drug, cysteamine, in pharmaceuticals. A linear working range for cysteamine concentrations from 3 × 10 -8 to 7.5 × 10 -6 molL-1 (r > 0.9907, n = 5) and a detection limit of 7.8 × 10-9 molL-1 were obtained, respectively. The relative standard deviation for five repetitive determinations was less than 3.8 %, with estimated recoveries of 100.1 % and 103.4 %. This method shows high sensitivity for the assay of cysteamine.

Water decreases the brightness of the peroxyoxalate chemiluminescence partially due to the hydrolysis of the oxalate reagent. Here, we show that encapsulation of an oxalate ester and the fluorescent activator in microspheres of cellulose esters increases the emission intensity 30 times compared to the same reaction in water without encapsulation, whereas the emission intensity decay rate constants are considerably lower. Emission intensities, rate constants and chemiluminescence quantum yields increase with increasing hydrogen peroxide concentrations. These results expand the potential of application of chemiluminescence, contributing for the development of ultrasensitive analytical methods.

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Given that light is hard to reach deep tumor tissue, how to enhance photodynamic therapy (PDT) efficacy is a big challenge. Herein, we proposed the supramolecular polymer self-assemblies (HACP) with bis[2,4,5-trichloro-6 (pentyloxycar-bonyl) phenyl] oxalate as the cargos (HACP@CPPO) to realize the chemiluminescence resonance energy transfer (CRET)-induced generation of 1O2 in situ. HACP was prepared by cinnamaldehyde-modified hyaluronic acid (HA-CA) and β-cyclodextrin-modified protoporphyrin IX (β-CD-PPIX) via host-guest interactions. The CA moiety could elevate H2O2 levels for the enhanced production of chemical energy and macrocyclic CD could enhance the stacking distance of PPIX for enhanced 1O2 yield. Thus, HACP@CPPO exhibited excellent antitumor performance without light irradiation.

Graphene quantum dots (GQDs), as one of the most promising luminescent nanomaterials, have been receiving increasing attention in various applications. However, it is still a challenge to improve their chemiluminescence (CL) quantum efficiency. Herein, the CL emissions of nitrogen- and sulfur-doped GQDs (NS-GQDs), nitrogen-doped GQDs (N-GQDs) and undoped GQDs synthesized through one-pot high-temperature pyrolysis are investigated in their chemical reactions with bis(2-carbopentyloxy-3,5,6-trichlorophenyl) oxalate (CPPO) and hydrogen peroxide (H2O2). A bright blue emission, and yellowish green and yellowish white light from NS-GQDs, N-GQDs and GQDs can be observed, respectively, in the mixture solutions with CPPO and H2O2. For the first time, spooling CL spectroscopy was used to investigate the CL reaction mechanisms, illuminant decays and the absolute CL efficiencies of these three GQD systems. Compared with the same system of undoped GQDs, it has been found that the NS-GQDs not only present slower illuminant decay, but also display an absolute CL quantum efficiency of 0.01%, 5-fold enhancement, due to the increase in N and S doping for a well-defined band gap energy. Moreover, three peak wavelengths attributed to intrinsic emission at 425 nm, aggregation-induced emission (AIE) at 575 nm and S-doped emissive surface states at 820 nm are observed for the first time in the NS-GQD system. The CL spectrum of N-GQDs displays two emission peaks at 395 and 575 nm attributed to intrinsic emission and AIE, whereas the CL spectrum of undoped GQDs demonstrates 500 nm and 600 nm peak wavelengths attributed to core emission and AIE. Absolute CL quantum efficiencies from these emissions at these various peaks can be determined quantitatively. This study provides guidance on tuning the surface states of GQD for more conducive injection of electrons and holes, facilitating the production of CL emission, which is beneficial for promoting the development of optical, bioassay and energy conversion applications.

We examined the possibility of detecting water vapor by chemiluminescence using the reaction of popular “chemical light” (bis(2,4,5-trichlorophenyl-6-carbopentoxyphenyl)oxalate with H2O2). H2O2 is released from sodium percarbonate exposed to water molecules as in the oxygen bleach. The release of H2O2 by water vapor was confirmed by mass spectrometry in a vacuum. The chemiluminescence from the mixed reagents was observed when exposed to water vapor. This method opens the way to locally detect the faulty points of water barrier films and observe the real-time failure of the barrier films during bending tests of flexible packing materials. A molecular dynamics simulation was performed to study the diffusion of H2O2 molecules in polymers.

Volatile formaldehyde (FA) in exhaled breath (EB) is considered as a biomarker for lung cancer (LC). On-the-spot selective and sensitive detection of gaseous FA is rather important for LC screening and diagnosis. Herein, a tetrakis(4-pyridylphenyl)ethylene (Py-TPE)-based zinc metal-organic framework (MOF) with excellent aggregation-induced emission (AIE) property was utilized for absorption and selective detection of FA in EB. The porous Zn-Py-TPE served as a gaseous confinement cavity for the adsorption of FA in EB. Interestingly, Zn-Py-TPE was aggregated on paper, and then aggregation-induced chemiluminescence (CL) emission can be triggered by only adding bis(2,4,6-trichlorophenyl)oxalate (TCPO). Though without H2O2, the CL of Zn-Py-TPE-TCPO was enhanced greatly by FA. FA promoted the aggregation of Zn-Py-TPE on paper by forming halogen bonding between FA and Zn-Py-TPE, which contributed to the better selectivity. FA can also stimulate the production of more singlet oxygen (1O2) in the Zn-Py-TPE-TCPO CL system. Hence, FA could be detected via the proposed Zn-Py-TPE-TCPO system with a quantification linear range of 1.0-100.0 ppb and detection limit of 0.3 ppb. This portable, low-cost, and sensitive paper-based platform can achieve trace FA detection in EB and is expected to provide an on-the-spot screening platform for lung cancer.

Chemiluminescence substances that respond to hydrogen peroxide (H2O2) in a tumor microenvironment have the potential to achieve accurate tumor imaging. Here, Pluronic F-127 (PF127) and polymers containing oxalate ester (POE) were assembled by hydrophilic and hydrophobic forces to form nanoparticles to load the anti-tumor drug lapachone (Lapa) and rubrene. The Lapa-loaded H2O2-responsive nanoparticles (L-HPOX) could track tumors in vivo through H2O2-related chemiluminescence. With the presence of H2O2 in the tumor microenvironment, L-HPOX would collapse and release the loaded drug for anti-tumor therapy. After treatment with 5,6-dimethylxanthenone-4-acetic acid (DMXAA), the inflammatory level and H2O2 content increased. Thus, L-HPOX exhibited good capabilities of tumor imaging and treatment. Importantly, the immune system was also activated for anti-metastatic activity. This intelligent and efficient chemiluminescent tumor theranostic nanoplatform will find great potential for precise and efficient tumor treatment.

Herein, a simple and portable paper-based analytical device (PAD) based on the inherent capability of carbon quantum dots (CQDs) to serve as a great emitter for the bis(2,4,6-trichlorophenyl) oxalate (TCPO)-hydrogen peroxide (H₂O₂) chemiluminescence (CL) reaction is introduced for the detection of harmful mercury ions (Hg2+ ). The energy is transferred from the unstable reaction intermediate (1,2-dioxetanedione) to CQDs, as acceptors, and an intensive orange-red CL emission is generated at about 600 nm, which is equal to the fluorescence emission wavelength of CQDs. The analytical applicability of this system was examined for the determination of Hg2+ . It was observed that Hg2+ could significantly quench the produced emission, which can be attributed to the formation of a stable and non-luminescent Hg2+ -CQDs complex. Accordingly, a simple and rapid PAD was established for monitoring Hg2+ , with a limit of detection (LOD) of 0.04 μg mL-1 . No interfering effect on the signal was found from other examined cations, indicating the acceptable specificity of the method. The designed assay was appropriately utilized to detect the Hg2+ in cosmetic samples with high efficiency. It is characterized by its low-cost, easy-to-use, facile but, accurate, and high selective for the detection of Hg2+ ions. Besides, the portability of this probe makes it suitable for on-site screening purposes.

In this paper, a peroxyoxalate chemiluminescence (CL) recovery system based on the interaction of N-doped graphene oxide nanosheets (N-GONs) and an oligopeptide for copper(II) ion detection has been reported. N-GONs as an excellent CL enhancer are prepared by the hydrothermal method using citric acid and ammonia, and the morphology and structure are characterized in detail by TEM, XPS, FT-IR and UV/vis, etc. In the bis(2,4,6-trichlorophenyl)oxalate (TCPO) and hydrogen peroxide (TCPO + H2O2) CL reaction system, the addition of N-GONs gives a remarkable CL emission, which can be quenched by an oligopeptide composed of ten amino acid residues due to the interaction between the N-GON plane and the oligopeptide strand. While in the presence of copper(II) ion, the quenched CL is recovered gradually along with the addition of copper(II) ion in the system. Based on the above CL reactions, a TCPO + H2O2 + N-GONs + oligopeptide CL system is constructed, achieving an ultra-sensitive and selective detection of copper(II) ion in environmental water samples. The detection limit of this method is as low as 0.2 pmol L-1, which is at least three orders of magnitude lower than other CL methods. The N-GONs and oligopeptide involved in the CL system are environmentally friendly, making it possess potential in the detection of copper(II) ion in environmental water samples.

Peroxyoxalate chemiluminescence is used in self-contained light sources, such as glow sticks, where oxidation of aromatic oxalate esters produces a high-energy intermediate (HEI) that excites fluorescence dyes via electron transfer chemistry, mimicking bioluminescence for efficient chemical energy-to-light conversion. The identity of the HEI and reasons for the efficiency of the peroxyoxalate reaction remain elusive. We present here unequivocal proof that the HEI of the peroxyoxalate system is a cyclic peroxidic carbon dioxide dimer, namely, 1,2-dioxetanedione. Oxalic peracids bearing a substituted phenyl group were unable to directly excite fluorescent dyes; hence, they could be ruled out as the HEI. However, base-catalyzed cyclization of these species results in bright chemiluminescence, with decay rates and chemiexcitation quantum yields that are influenced by the electronic phenylic substituent properties. Hammett (ρ = +2.2 ± 0.1) and Brønsted (β = -1.1 ± 0.1) constants for the cyclization step preceding chemiexcitation imply that the loss of the phenolate-leaving group and intramolecular nucleophilic attack of the percarboxylate anion occur in a concerted manner, generating 1,2-dioxetanedione as the unique outcome. The presence of better leaving groups influences the reaction mechanism, favoring the chemiluminescent reaction pathway over the nonemissive formation of aryl-1,2-dioxetanones.

Aggregation-induced emission (AIE) molecules that can avoid the aggregation-caused quenching (ACQ) effect and break the concentration limit have been widely used for biosensing. Similar to fluorescence dyes, AIE molecules can be chemiexcited simply by a peroxyoxalate-based chemiluminescence (CL) reaction, but the hydrolysis of peroxyoxalate is often a problem in an aqueous solution. Herein, we report an AIE effect within peroxyoxalate-loaded silica nanoparticles (PMSNs) for an efficient harvest of CL energy as well as alleviation of bis(2,4,5-trichloro-6-carbopentoxyphenyl) oxalate (CPPO) hydrolysis. Peroxyoxalate (i.e., CPPO) and AIE molecules (i.e., 1,2-benzothiazol-2-triphenylamino acrylonitrile, BTPA) were loaded together within the mesoporous silica nanoparticles (MSNs) to synthesize the BTPA-PMSN nanocomposite. The BTPA-PMSNs not only allowed CPPO to be dispersed well in an aqueous solution but also avoided the hydrolysis of CPPO. Meanwhile, the proximity between BTPA and CPPO molecules in the mesopores of MSNs facilitated the BTPA aggregate to harvest the energy from CL intermediates. Hence, the CL system of BTPA-PMSNs can work efficiently in aqueous solutions at a physiological pH. The CL quantum yield of the BTPA-PMSN system was measured to be 9.91 × 10-5, about 20 000-fold higher than that obtained in the rhodamine B (RhB, a typical ACQ dye)-PMSN system. Using BTPA-PMSNs for H2O2 sensing, a limit of detection (LOD) as low as 5 nM can be achieved, 1000-fold lower than that achieved in the RhB-PMSNs system. Due to the feasibility of working at a physiological pH, this CL system is also quite suitable for the detection of oxidase substrates such as glucose and cholesterol. This BTPA-PMSN CL system with the merits of high CL quantum yield at a physiological pH is appealing for biosensing.

Various CRISPR/Cas12a-based biosensing systems have been developed in the past few years, and most of these systems used Taqman probes to report signals through fluorescence resonance energy transfer (FRET). In this study, we explored chemiluminescence resonance energy transfer (CRET) as the readout mode for CRISPR/Cas12a-based biosensing. The chemiluminescence (CL) reaction of bis(2,4,6-trichlorophenyl) oxalate (TCPO) and H2O2 was used to excite the fluorophore dye of the Taqman probe. Different from FRET, CRET does not need external excitation light, which can effectively avoid autofluorescence and photobleaching. The detection limit of this CRET readout mode was estimated to be 10 pM for target DNA, which was about 8 times lower than that of the widely used FRET readout mode. These results suggest that CRET can serve as a rapid, sensitive and simple readout mode of CRISPR/Cas12-based biosensing, and can further enrich the toolbox of CRISPR/Cas12-based biosensing.

A luminescent metal organic frameworks (MOFs)-based chemiluminescence resonance energy transfer (CRET) platform was constructed for turn-on detection of fluoride ion. A hybrid MOFs was prepared by encapsulating strong fluorescence 2',7'-dichlorofluorescein (DCF) into the frames of NH2-MIL-101(Al) MOFs, which led to a significant suppression of fluorescence signal of DCF. In the presence of fluoride ion, it destroyed the structure of the hybrid MOFs and released DCF molecules from the frames due to the formation of more stable aluminum hexafluoride complex ions [AlF63-] between fluoride ion and aluminum ion. The released DCF molecules accepted the energy originating from the chemical reaction of bis(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide (H2O2), producing a strong chemiluminescence (CL) emission. The CL signal was strong dependent on the concentration of fluoride ion presented and showed a linear response in the range of 0.5-80.0 μmol L-1 (9.5 μg L-1-1.52 mg L-1). The detection limit was 0.05 μmol L-1 (about 0.95 μg L-1) fluoride ion and the relative standard deviations was 2.3% for 40.0 μmol L-1 fluoride ion solution (n = 11). This MOFs-based CRET method was successfully applied to the determination of fluoride ion in drinking water samples, demonstrating its potential application in analysis of real samples.

The residues of pyrethroids in foods of animal origin are dangerous to the consumers, so this study presented a chemiluminescence sensor for determination of pyrethroids in chicken samples. A dual-dummy-template molecularly imprinted polymer capable of recognizing 10 pyrethroids was synthesized. The results of computation simulation showed that the specific 3D conformations of the templates had important influences on the polymer's recognition ability. The polymer was used to prepare a sensor on conventional 96-well microplates, and the sample solution was added into the wells for direct absorption. The absorbed analytes were initiated with the bis(2,4,6-trichlorophenyl)oxalate-H2 O2 -imidazole system, and the chemiluminescence intensity was used for analyte quantification. Results showed that one assay was finished within 12 min, and this sensor could be reused four times. The limits of detection for the 10 analytes were in the range o0.3-6.0 pg/ml, and the recoveries from the standards of fortified blank chicken samples were in the range 70.5-99.7%.

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This work reports a fully exposed palladium cluster catalyst that exhibits superior activity and selectivity for methyl nitrite (MN) carbonylation compared to atomically dispersed Pd catalysts and Pd nanoparticles. Mechanistic studies reveal that the distinct geometric structure of the fully exposed palladium cluster enables surface-mediated Langmuir-Hinshelwood reactions, efficiently producing dimethyl carbonate (DMC) while minimizing dimethyl oxalate (DMO) formation. In contrast, atomically dispersed Pd catalysts rely on Eley-Rideal mechanisms, leading to lower activity, while the continuous surface sites of Pd NPs promote DMO formation. This work provides a foundation for the rational design of novel catalysts for industrial carbonylation processes.

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Dimethyl carbonate and dimethyl oxalate are competitive products of the carbonylation reaction of methyl nitrite (MN) under Pd-based catalysts. The chemo-selectivity is influenced not just by the thermodynamic constraints of reaction conditions but also by the electronic structures of catalysts. Lewis acid sites are extensively employed to modulate the electronic structures of Pd active sites for kinetic carbonate production, but their precise role remains unclear. Herein, we employed a combination of reaction kinetic, in situ DRIFTS experiments and DFT calculation, unveiling the indispensable role of Lewis acid sites in activating MN and facilitating the transfer of *OCH3 species, which is the key to obtain the kinetic carbonate outcome. The molecular understanding reveals the cooperation of Pd center and Lewis acid sites in directing selectivity towards carbonate product, which enables the rational design of higher-performance catalysts.

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The selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) is becoming more and more attractive for the industrial production of polyglycolic acid (PGA) biodegradable plastics. However, it is...

Partial hydrogenolysis of dimethyl oxalate (DMO) to methyl glycolate (MG) is a central step in biodegradable polyglycolic acid (PGA) production. However, it remains a great challenge for efficient and selective DMO hydrogenolysis under mild temperature (<100°C). In this work, we demonstrate an outstanding DMO hydrogenolysis by employing alkaline (Na, K) metal‐doped Ru catalysts. Na presents a stronger promotional effect than K. The highest yield of MG is achieved at 90.2% at 85°C in 15 h of reaction on 3Ru‐0.4Na/SiO 2 and the catalyst can be directly reused more than 10 times without any additional regeneration. The doping of Na effectively enables smaller Ru nanoparticle size, larger capacity of H 2 adsorption via a hydrogen pool (includes surface hydride, i.e., Na‐H δ − ) on Ru–Na interface, stronger strength of DMO adsorption. It is further revealed that there is a linear relation between the content of surface Ru 0  + Ru 3+  + Ru δ − and MG yield. Finally, an optimal ratio of Ru 3+ + Ru δ − /Ru 0 of 1.26 is achieved.

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Producing methyl glycolate (MG) as a feedstock of degradable plastics from hydrogenation of dimethyl oxalate (DMO) is a sustainable and economical route. However, the MG yield is susceptible to the reaction temperature over Cu‐based catalysts due to the oxidation of Cu0 to Cu+, exhibiting a see‐saw effect on DMO conversion and MG selectivity. Increasing temperature favors the DMO conversion but will accelerate the formation of Cu+ and promote the further hydrogenation of MG. In this work, we found that the P promoter could tailor the ratio of Cu0/Cu+ to improve the DMO conversion while maintaining the high MG selectivity for sputtered Cu catalysts. The MG yield of SP‐Cu/SiO2 with 0.25 wt% P promotor can reach 72%, which was 6 times higher than that on the unpromoted catalyst at 270 °C. Characterizations demonstrated that the P addition could induce Cu+ generation during the sputtering process, ensuring efficient DMO conversion. Meantime, the electron‐donating effect of P could strengthen the oxidation‐resistance property of the sputtered Cu, inhibiting further MG hydrogenation. This work provides a novel strategy to adjust Cu species during both preparation and reaction process.

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The catalytic co‐coupling of carbon monoxide and methyl nitrite to synthesize dimethyl oxalate (DMO) is a crucial step in the conversion of syngas to ethylene glycol. Recent advancements in numerical simulation methodologies substantially enhanced the potential for optimizing chemical production processes, thereby improving cost effectiveness and efficiency. Numerical simulation techniques were applied to model a shell‐and‐tube reactor and a radial reactor. The distributions of pressure, velocity, reaction, and temperature fields were analyzed for both reactor configurations under similar operating conditions. The findings indicate that the radial reactor has different advantages, including a smaller volume, a more uniform temperature distribution, and a lower pressure drop, highlighting its potential benefits in the DMO synthesis process.

This research introduces the TA-informer, a novel model developed to enhance the prediction of key quality indicators in the Dimethyl Oxalate Synthesis(DMOS) process, where reliance on costly and time-consuming offline laboratory analysis often creates significant bottlenecks, particularly in Few-Shot Learning scenarios. The TA-informer combines diverse self-attention and cross-attention mechanisms to concurrently capture long-term dependencies and relationships among multiple time series. It also integrates an adversarial learning strategy utilizing minimax games to interpret complex data distributions effectively. Moreover, the model incorporates a deep transfer learning framework designed to utilize extensive datasets from distributed control systems and online analyzers, thus facilitating efficient information transfer to the target domain with limited OLA data. Empirical comparisons with several advanced methods demonstrate the TA-informer's superior capabilities within the DMOS process in Few-Shot settings, showcasing its potential to mitigate existing analytical challenges significantly.

The activated carbon (AC) supported alkali carbonate catalysts were investigated for dimethyl oxalate (DMO) decarbonylation to dimethyl carbonate (DMC) in a fixed-bed reactor. Among the tested catalysts, K2CO3 supported on AC demonstrated superior performance. Systematic optimization of the preparation conditions identified 200 °C and 20 wt% as the optimal calcination temperature and K2CO3 loading, respectively, achieving the highest DMO conversion and DMC selectivity. The introduction of KBr as a modifier provided a marked improvement, enhancing DMC selectivity from 83.10% to 89.19%. However, during a 20 h stability test, the 10%KBr + 20%K2CO3/AC catalyst exhibited a gradual decline in DMC selectivity. This deactivation is attributed to the leaching of KBr and the formation of potassium oxalate (K2C2O4) via DMO hydrolysis, which is triggered by trace water in the feedstock. Consequently, the trace amount of water in the feedstock would influence both the DMO conversion and DMC selectivity.

Dimethyl oxalate (DMO) hydrogenation is a pivotal process for transforming non-petroleum carbon resources into high-value chemicals such as methyl glycolate, ethylene glycol, and ethanol. Despite its potential for enabling carbon...

The development of highly efficient catalyst for selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) is an important step in the conversion of syngas into high-value chemicals, which...

This paper focuses on dimethyl oxalate and, based on the results of HAZOP analysis for its synthesis process, conducts the following studies: (1) establish a safety evaluation index system for dimethyl oxalate synthesis using hierarchical analysis and calculate the weights of each indicator, determining the acceptable range of each indicator according to the 3σ criterion, (2) develop an evaluation index scoring method based on this, (3) classify the overall process safety into four levels: safe, relatively safe, unsafe, and extremely unsafe based on the evaluation index scores and corresponding weights.

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ABSTRACT Significant efforts have been directed toward the advancement of active and durable Pd−based catalysts for the gas−solid phase oxidative coupling of carbon monoxide (CO) to dimethyl oxalate (DMO). The reaction takes place under moderate conditions with high selectivity above > 95% following the C1 chemistry route and converting C1 feedstocks, i.e. CO and methanol (CH3OH) to DMO product. The inaugural plant capable of processing 200,000 tons annually, was commissioned in 2009, and as of 2023 more than 30 such plants are in operation. Noteworthy attention has been dedicated to enhancing catalytic activity while minimizing the Pd active component, achieved through the construction of efficient nanostructured catalysts. In this review, we highlight the recent advances in the CO oxidative coupling to DMO, particularly focusing on the design of Pd−based catalysts, structure−function relationship, catalytic reaction mechanism and process intensification utilizing structured catalysts. Additionally, an overview addressing challenges and opportunities for future research associated with CO oxidative coupling to DMO is presented. Graphical abstract

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CO oxidative coupling to dimethyl oxalate (DMO) is an important approach for the product of ethylene glycol and CO elimination. In this work, the Co doped Pd/Al2O3 nanocatalyst was highly effective for CO oxidative coupling and enhanced remarkably CO conversion and the formation of DMO. The maximum DMO STY reached 1082 g L−1 h−1 over the Pd/Al2O3@1/20Co catalyst at 130 °C for 2 h under the space velocity of 3000 h−1, which is two times higher than that over the Pd/Al2O3 catalyst. The Co modification and its influence on the structure of the Pd/Al2O3 catalyst were also studied systematically by XRD, TEM, CO‐TPD, N2 physical adsorption and XPS techniques. An appropriate Co doing was confirmed to promote distinctly the generation of smaller Pd particles and the adjustment of the adsorption or activation of CO over the catalyst. A positive interaction between Pd nanoparticles and the modulated support with Co doping was demonstrated and favored the enhanced activity of the catalyst for the reaction.

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Here, we report the assembly of plasmonic copper nanoparticles capped by poly (vinyl alcohol) via esterification with oxalic acid (OA) as a crosslinking agent. As-synthesized copper nanoparticles measure 8.6 nm and are single crystals, displaying a plasmonic resonance at 392 nm. An increase in the reaction time from 15 to 240 min leads to the assembly of nanoparticles into clusters with decreasing interparticle distances. This is reflected in the appearance of the second plasmon resonance at a longer wavelength, whose intensity and position depend on the reaction time. The influence of the interparticle distance between the assembled copper nanoparticles on the wave propagation of visible light and the optical parameters was studied. The results revealed that decreased interparticle distance between the copper nanocrystals increases the plasmon pulsation frequency and the penetration depth of visible light. This new finding remarkably enhanced the surface plasmon polariton and the surface plasmon resonance along the interface between the dielectric medium and copper nanocrystals. Therefore, the developed nano‑copper assembly with various interparticle distances exhibited outstanding photothermal performance under visible light irradiation for the first time. The study of the antibacterial activity of assembled copper nanoparticles against hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) under visible light irradiation revealed a remarkable efficiency of the nanoparticle sample obtained after 30 min of the reaction with OA and containing medium-size clusters with the interparticle distance of 0.9 nm. This was attributed to an optimal cluster size, allowing easy penetration of the bacterial cell membrane and the comparatively small interparticle distance between copper nanoparticles, leading to strong interparticle interactions and influencing antibacterial activity. This unique feature may open a new avenue for using the proposed synthetic recipe as an alternative for photothermal therapy under visible irradiation instead of laser or UV irradiation with serious harmful effects on living cells.

This work aims to investigate the effects of deep eutectic solvents (DES) on the chemical and physical structure of cellulose. Choline chloride-oxalic acid and choline chloride-oxalic acid-glycerol were selected as solvents and cotton fibers was sued as raw materials to explore the difference between cotton fibers treated separately with two different DES. According to yield analysis, ternary solvents alleviated the degradation of cellulose when comparing to binary solvents, resulting in over 90 % of cellulose being obtained. Particularly, there is an esterification reaction of cellulose during treatment with the DES system, which also affects the performance of the subsequent products. Through the simple use of mechanical foaming with polyvinyl alcohol and the palm wax impregnation process, foams with a water contact angle greater than 140° and excellent mechanical properties can be obtained. The resultant foam material has 5 % linear elastic area, and prominent compressive strength providing potential use in the packaging industry in the replacement of plastic.

The scCO2-assisted organosolv pretreatment of sugarcane bagasse was carried out using aqueous ethanol and organic acid catalysts. Variables involved were temperature (150-190 °C), time (0-60 min), type of catalyst (acetic, citric, and oxalic acids), amount of CO2 (25-50 g), ethanol titer in water (0-80 vol%), and catalyst concentration (0.5 to 1.5 % w·v-1). The best delignification (86 wt%) and glucan retention (89 wt%) were achieved at 170 °C for 15 min using 60 vol% ethanol in water, 1 wt% oxalic acid, and 25 g CO2. Organic acid esterification was a limitation for pretreatment operations using ethanol titers above 60 vol%. Enzymatic hydrolysis of pretreated materials at 1 % (w·v-1) glucans released 74.3 ± 0.2 % glucose in 96 h using Cellic CTec3 (Novozymes) at 9.89 FPU·gglucans-1. The concentrated pretreatment liquor allowed lignin recovery by water precipitation in high yields, while the aqueous supernatant contained low levels of fermentation inhibitors.

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A series of isoquercitrin (quercetin-3-O-β-d-glucopyranoside) esters with mono- or dicarboxylic acids was designed to modulate hydro- and lipophilicity and biological properties. Esterification of isoquercitrin was accomplished by direct chemoenzymatic reaction using Novozym 435 (lipase from Candida antarctica), which accepted C5- to C12-dicarboxylic acids; the shorter ones, such as oxalic (C2), malonic (C3), succinic (C4) and maleic (C4) acids were not substrates of the lipase. Lipophilicity of monocarboxylic acid derivatives, measured as log P, increased with the chain length. Esters with glutaric and adipic acids exhibited hydrophilicity, and the dodecanedioic acid hemiester was more lipophilic. All derivatives were less able to reduce Folin–Ciocalteau reagent (FCR) and scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) than isoquercitrin; ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) radical-scavenging activity was comparable. Dodecanoate and palmitate were the least active in FCR and ABTS scavenging; dodecanoate and hemiglutarate were the strongest DPPH scavengers. In contrast, most derivatives were much better inhibitors of microsomal lipoperoxidation than isoquercitrin; butyrate and hexanoate were the most efficient. Anti-lipoperoxidant activity of monocarboxylic derivatives, except acetates, decreased with increasing aliphatic chain. The opposite trend was noted for dicarboxylic acid hemiesters, isoquercitrin hemidodecanedioate being the most active. Overall, IQ butyrate, hexanoate and hemidodecanedioate are the most promising candidates for further studies.