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ABSTRACT β‐Lactams, as nitrogen‐containing heterocycles with distinctive biological activities, have made significant contributions to the treatment of infectious diseases. This study which used inexpensive copper salts as catalysts, trichloroacetonitrile as a radical precursor, and potassium carbonate as base offers a concise route for the synthesis of β‐lactam compounds substituted with potentially pharmacologically active dichloroacetyl moieties. Preliminary mechanistic studies indicate that unactivated alkenes undergo sequential intermolecular radical addition and intramolecular amidation reactions. The copper salts undergo catalytic cycles involving Cu(I)/Cu(II)/Cu(III) species. [ABSTRACT FROM AUTHOR]

An efficient one-step procedure for the synthesis of a new series of multifunctional olefins by condensation of α-substituted β-diketones as well as β-phosphonoesters and benzoylated β-ketoesters with formaldehyde, using potassium carbonate in refluxing THF, followed by a deacylation reaction, is herein described. In contrast, the α-substituted β-keto esters, bearing an acyl moiety, only undergo a hydroxymethylation reaction, with no metal catalysts/activating agents, as is usually required for the process, affording the corresponding α-hydroxymethyl β-keto esters in high yields. [ABSTRACT FROM AUTHOR]

This study investigates the impact of zirconium-based KZC series crosslinkers with varying zirconium contents and the polyamine-based crosslinker (PBC) on the properties of coated paper, focusing on key performance metrics such as viscosity, wet rub and pick resistance, dry pick resistance, gloss, brightness, ink set-off, and print mottle. The findings reveal that crosslinkers' type and concentration significantly influence the coating colors' viscosity, with PBC demonstrating lower low shear viscosity at lower concentrations. The KZC series showed stable viscosity across a zirconium content range of 7% to 20%, and both crosslinker types enhanced wet rub resistance at higher concentrations. Notably, the KZC series, particularly KZC7, exhibited superior wet pick resistance at increased concentrations, highlighting its effectiveness in enhancing the durability of the coating layer. All crosslinkers maintained excellent dry pick resistance, ensuring robust coating performance. While gloss and brightness were generally unaffected, KZC20, which had the highest zirconium content, slightly reduced these optical properties. Ink set-off tests indicated that the KZC series performed better at lower concentrations, whereas higher concentrations led to increased ink set-off, potentially due to over-crosslinking. Print mottle remained consistent across all crosslinkers, indicating uniform coating quality. Overall, the zirconium-based KZC series significantly enhances wet resistance and maintains high performance across various properties, though it may slightly reduce gloss and brightness and increase ink set-off at higher concentrations. PBC offers a balanced performance profile, emphasizing the need for careful crosslinker type and concentration optimization to achieve the desired coating properties for specific applications. This comprehensive evaluation provides valuable insights for developing and optimizing high-performance coated papers. [ABSTRACT FROM AUTHOR]

The synthesis of dimethyl carbonate (DMC) from methanol and CO2 has also received widespread attention, and K2CO3 is usually used as a catalyst in the synthesis of DMC. In this work, the role of K2CO3 in synthesizing dimethyl carbonate (DMC) from methanol and CO2 was revisited. Interestingly, NMR results indicated that K2CO3 can react with methanol to form carbonate CH3OCOO−, an essential intermediate in the synthesis of DMC, which can be transformed into DMC in the presence of CH3I. In other words, K2CO3 can act as not only a catalyst but also a reactant to synthesize DMC from methanol and CO2. [ABSTRACT FROM AUTHOR]

The loss of quality of wolframite concentrates determines the need to improve their processing method that ensures maximum conversion of tungsten into water-soluble wolframate and a reduction in water-soluble impurities. The results of thermodynamic modeling of the sintering of wolframite concentrate with sodium and potassium carbonates indicate a greater efficiency of K2CO3: The reagent consumption required for complete conversion of tungsten into solution decreases from 170% from stoichiometric sintering with Na2CO3 to 110% for K2CO3, as well as the proportion of soluble silicates up to 0.1%. In addition, sintering with K2CO3 is accompanied by the formation of compounds with a higher melting point, preventing melting and coating formation during the process. Mathematical sintering models were obtained by the method of probabilistically deterministic planning of this experiment. Optimal parameters have been determined: The extraction of tungsten into a solution of more than 95% is achieved by sintering with K2CO3 in an amount of 105–110% according to the stoichiometric requirements for the formation of K2WO4, K2MoO4, and K2SO4 at temperatures of 1073–1123 K for 100–120 min. Pilot tests have confirmed the effectiveness of the process. The possibility of sintering a cinder of wolframite concentrate with K2CO3 without the introduction of recycled materials has been established. Sintering under optimal conditions ensures the transition of tungsten to water-soluble tungstate by 97.5%. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANN) are a nondestructive method for estimating fruit and vegetable shelf life and quality attributes. This research used artificial neural networks to model a storage process for fruit grapes (Vitis vinifera cv. Rishbaba) coated with maltodextrin, including different levels of potassium nanocarbonate (0-2%) and pyracantha extract (0-1.5%). After applying these coatings, the fruits were stored for 60 days in cold storage (-1 °C), with a relative humidity of 90%. Measurements considered weight loss percentage, titrable acidity (TA), pH, texture firmness, color index (a*), and general fruit acceptance. Artificial neural networks predicted changes in fruits during the storage process. By examining different networks, the feedforward backpropagation network had 3-10-6 topologies with a coefficient of determination (R2) greater than 0.988 and a mean square error (MSE) less than 0.005. With a hyperbolic sigmoid tangent activation function, a resilient learning pattern and 1000 learning process were determined as the best neural method. On the other hand, the results of the optimized models showed that this model had the highest and lowest accuracy for predicting the weight loss percentage (R2 = 0.9975) and a* (R2 = 0.5671) of the samples, respectively. [ABSTRACT FROM AUTHOR]

A truly organocatalytic approach to the Darzens reaction affording α,β-epoxy carbonyl compounds in good yields was developed taking advantage of the high basic strength and low nucleophilicity of cyclopropenimine superbases. The catalytic active free base can easily be generated in situ from its hydrochloride salt and maintained in the active deprotonated form by performing the reactions in a heterogeneous reaction system in the presence of excess potassium carbonate as a sacrificial base. [ABSTRACT FROM AUTHOR]

Summary In this research, the effects of washing treatments (potassium carbonate (PC), potassium hydroxide (PH), peracetic acid (PA), alkaline hydrogen peroxide (AHP)), ultrasound (US) and high‐intensity pulsed light (HIPL) technologies on the removal of ochratoxin A (OTA) residues in raisins were investigated. PC at 5 min (66.60%), PH at 10 min (65.25%), alkaline hydrogen peroxide at 5 min (63.30%) and HIPL at 12 J cm−2 (62.50%) were found to be the most successful applications in OTA degradation, respectively. Although the OTA degradation rate was high after chemical washing for 10 min, the raisins had a chemical odour. The results show that HIPL effectively reduces OTA levels in raisins without causing any quality loss. [ABSTRACT FROM AUTHOR]

Maintainance of extracellular volume and water balance is important in cellular metabolism and these properties confer to sodium profile, but overconsumption of sodium causes risk to health. The present study aimed to develop and evaluate fastdissolving effervescent tablets using a novel two-step wet granulation method, incorporating Olive (Olea europaea), halophyte marsh plant (Salicornia herbacea L.) and bamboo silica salts natural ingredients and edible organic acids viz. citric acid, malic acid, tartaric acid, apple cider vinegar powder, fumaric acid and alkalizing agents like sodium bicarbonate, anhydrous potassium carbonate, anhydrous sodium carbonate, potassium sulphate dodecahydrate as active ingredients to enhance bioavailability and dissolution. During the process, all active ingredients were milled separately and sifted through a number 40 mesh sieve, followed by blending for 10 min to create uniform wet mass and further, sieved through number 20 mesh to produce granules. Finally, the dried granules of the composition according to formulations were compressed into tablets with 12 mm diameter using a single punch tablet punching machine. The formulations adhered to pharmacopoeial quality standards, displaying favorable mechanical and physical properties. The results revealed that the effervescent granules in all the formulations exhibited excellent flow properties with Angle of Repose, Hausner's ratio and compressibility index in the ranges of 26.10°-29.52°, 1.07-1.12 and 6.12%-10.51% respectively. Formulations F1 and F3 emerged as the most effective, with friability <0.5%, water content <0.05%, effervescence time <2.5 min and excellent solubility on the Likert scale. The findings open avenues for further research into effervescent technology and its application in drug delivery systems. [ABSTRACT FROM AUTHOR]

The title compound, 4-(10-phenyl-9-anthracenyl)-1,2-benzenediol, was synthesized using a two-step protocol. In the first step, 9-phenyl,10-bromoanthracene was coupled to 3,4-dimethoyphenylboronic acid by employing Pd(PPh3)4 as the catalyst and potassium carbonate as the base. Methoxy group removal was effected using HBr in the presence of acetic acid in the second step. Overall, two novel 9,10-diphenylanthracence-based compounds were synthesized in this work; standard spectroscopic techniques and high-resolution mass spectrometry were employed in their characterization. The photophysical properties of these compounds are also reported. These compounds are potentially useful as sensors, catalysts and building blocks for larger architectures. [ABSTRACT FROM AUTHOR]

Understanding intermolecular interactions is important for the design of deep eutectic solvents. Herein, potassium carbonate (K2CO3) and ethylene glycol (EG) are used to form deep eutectic solvents. The interactions between K2CO3 and EG are studied using nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectra. Interestingly, the interaction results indicate that the carbonate anion CO 3 2 − can react with EG to form EG-based organic carbonate, which can occur even at room temperature. The possible reaction steps between K2CO3 and EG are presented. As K2CO3 can be prepared from CO2 and KOH, the findings of this work may provide a promising strategy for CO2 capture and conversion. [ABSTRACT FROM AUTHOR]

Thermochemical storage using salt hydrates presents a promising energy storage method. Ensuring the long-term effectiveness of the system is critical, demanding both chemical and mechanical stability of material for repetitive cycling. Challenges arise from agglomeration and volume variations during discharging and charging, impacting the cyclability of thermochemical materials (TCM). For practical usage, the material is often used in a packed bed containing millimetre-sized grains. A micro-level analysis of changes in a packed bed system, along with a deeper understanding involving quantifying bed characteristics, is crucial. In this study, micro X-ray computed tomography (XCT) is used to compare changes in the packed bed before and after cycling the material. Findings indicate a significant decrease in pore size distribution in the bed after 10 cycles and a decrease in porosity from 41.34 to 19.91% accompanied by an increase in grain size, reducing void space. A comparison of effective thermal conductivity between the uncycled and cycled reactor indicates an increase after cycling. Additionally, the effective thermal conductivity is lower in the axial direction compared to the radial. XCT data from uncycled and cycled experiments are further used to observe percolation paths inside the bed. Furthermore, at a system scale fluid flow profile comparison is presented for uncycled and cycled packed beds. It has been observed that the permeability decreased and the pressure drop increased from 0.31 to 4.88 Pa after cycling. [ABSTRACT FROM AUTHOR]

In this study, we explored the reactivity of meta‐trifluoromethanesulfonate (OTf) substituted diaryliodonium salts under alkaline conditions. Two distinct pathways with direct arylation of pyrrole derivatives and Diels‐Alder cycloaddition via aryne intermediates, have been found upon the relative alkalinity strength of potassium carbonates or hydroxides. This approach offers a straightforward and efficient route to synthesize heterocyclic aromatics under mild reaction conditions with tolerance of various functional groups. [ABSTRACT FROM AUTHOR]

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Microplastics are now ubiquitous in the environment and are even considered "technofossils" of the Anthropocene. Given their omnipresence and potential impact, identifying and analyzing these particles becomes increasingly crucial. Novel approaches suggest density gradient centrifugation for simultaneous extraction and fractionation of microplastic particles based on their plastic-specific densities. In this article we describe a cheap and harmless experimental setting to fractionate microplastic particles by density gradient centrifugation. An innovative low-cost Do-It-Yourself (DIY) gradient maker using Luer-Lock syringes is presented. With this gradient maker it is possible to produce density gradients with water and sucrose solutions, covering a density range of 1.00–1.32 g/cm3, as well as with water and saturated potassium carbonate solutions, covering a density range of 1.06–1.53 g/cm3. The separation performance was tested with the most broadly used plastics polyamide, polyurethane, polycarbonate, polyethylene terephthalate and polyvinylchloride. Both density gradients show centrifugation stability and clear banding patterns after centrifugation. Due to its cheap and easy-to-build-easy-to-use nature, this experimental setting for microplastic fractionation by density gradient centrifugation offers an approach for schools not only to address the microplastic problems, but also to integrate new methods of microplastic analysis in upper secondary school laboratories. [ABSTRACT FROM AUTHOR]

The utilization of activated carbon as an efficient adsorbent is well-established, driven by its porous structure and expansive surface area. This study investigates the potential of Cassia fistula (Golden shower) as a precursor for activated carbon synthesis using K2CO3 activation, leveraging its organic properties known for high porosity and adsorption capacity. This research aims to investigate the feasibility of utilizing Cassia fistula-derived activated carbon (GSAC) for isoniazid removal from water. The study encompasses a two-step activation process—chemical and physical—with varying parameters to optimize surface area and porosity. The carbonization process involves hydrothermal and pyrolysis techniques with controlled conditions. The temperature used in this study is based on the TGA analysis to examine its thermal stability. Batch experiments examine the adsorption equilibrium and kinetics of isoniazid onto GSAC samples, revealing high adsorption capacity and rapid equilibrium attainment by GSAC 1:1 (700°C). The study culminates in the identification of a strong chemical bond between GSAC and isoniazid, implying efficient adsorption potential as confirmed by FTIR and SEM analysis before and after adsorption. The adsorption characteristic is examined with an isotherm and kinetic model. The highest predicted GSAC capacity reaches 219,807 mg/g, emphasizing its promising adsorption capabilities. This work underscores Cassia fistula-based activated carbon as a viable, cost-effective, and eco-friendly adsorbent for isoniazid removal, with implications for diverse applications. The synthesis process parameters, activation methods, and insights into the adsorption mechanism contribute to the understanding of effective adsorbent production and enhance the potential of activated carbon for various industrial contexts.

The first study on oxidative sulfonamidation of camphene is presented. By varying the reaction conditions, the nature of the sulfonamide, the oxidizing agent, the ratio of the reagents, and the solvent, it is possible to control not only the direction of amidation of the double bond of camphene, leading to the formation of the corresponding amides or amidines, but also the rearrangement or retention of the camphene structure. In the NIS-induced reaction, no rearrangement occurs, leading to N-sulfonylamidine derivatives of isocamphane. The NBS-induced reaction takes place with solvent (acetonitrile) intersection and with or without rearrangement, resulting in N-sulfonylamine with isocamphane or camphane motif, depending, strikingly, on the ratio of the reactants. A mechanism that explains the diversity of products has been proposed and confirmed by theoretical calculations. It includes various intermediates formed via electrophilic addition of a halogen, such as an open carbocation for Br+, or the anchimerically assisted iodonium cation for I+. Additionally, the basicity of the reaction medium can change depending on the ratio of the reagents. For example, in CH2Cl2, which is incapable of being trapped by the intermediate cations, the formation of bromosulfonamide occurs only with triflamide due to the highest halogening activity of the intermediate CF3SO2NHBr. The structure of the products formed in up to 96% yield was proved by NMR, HRMS and, for the key products, by X-ray analysis. When performing the NBS-induced bromosulfonation of camphene using triflamide with subsequent addition of potassium carbonate (K2CO3), no dehydrobromination occurred. However, when using cesium fluoride (CsF) as a base, an unexpected quinazoline product was obtained. This opens up the possibility for further transformations. [ABSTRACT FROM AUTHOR]

Legumes, rich in protein, fiber, and micronutrients, are increasingly popular in pulse-based and gluten-free foods despite global consumption stagnating at 21 g/day due to taste, low protein digestibility, anti-nutrients, and long cooking times. Bean resistance to cooking causes textural defects like the hardshell and hard-to-cook phenomena. The pectin–cation–phytate hypothesis explains why soaking beans in sodium salts reduces cooking time by enhancing pectin solubility in water. Gradoli Purgatory beans (GPB), from Italy′s Latium region, were malted, reducing phytic acid by 32% and oligosaccharides by 63%. This study evaluated the hardness of cooked GPB seeds in various conditions, including decorticated or malted states, using a modified standard method. Cooking at 98 °C for 7–75 min on an induction hob with a water-to-seed ratio of 4 g/g was tested. Soaking was applied before cooking for conventional seeds only, followed by texture analysis. Conventional GPBs were adequately cooked if their cotyledons disintegrated upon pressing, requiring a force peak of 250 to 220 N and cooking times of 52 to 57 min. Malted, decorticated, and split GPBs cooked similarly to raw decorticated and split ones, with times of 32 and 25 min, respectively. Faster cooking was due to bean coat removal and splitting, not chemical changes. Sodium or potassium carbonate/bicarbonate at 1–2 g/L improved cooking efficiency, with 2 g/L of sodium carbonate reducing cooking time to 13 min. Higher concentrations caused non-uniform cooking. Cooking malted, decorticated, and split GPBs in sodium-carbonated water reduced greenhouse gas emissions from 561 to 368 g CO2e/kg, meeting the demand for eco-friendly and nutritionally enhanced plant protein sources. [ABSTRACT FROM AUTHOR]

The paper analyzes promising industrial processes for obtaining electrolytic hafnium powder. It is shown that extraction and iodide refining are the main processes used to purify hafnium from impurities, achieving both reactor-grade and high purity. The conducted studies have demonstrated the possibility of creating an alternative, more economical, and environmentally safe technology for hafnium recovery, compared to the current magnesium-thermal method. Production of reactor hafnium by electrolysis from molten electrolyte K2HfF6-KCl-KF is possible due to obtaining hafnium oxynitrate salt of nuclear purity and the creation of a hermetic electrolyzer. It is shown that the process of electrolysis leads to the accumulation of potassium fluoride in the electrolyte and requires its periodic draining with deterioration of technological indicators associated with increased recycling of the electrolyte. It was found that along with hafnium, metallic potassium is released on the cathode, which additionally worsens the technical and economic indicators of production. Sealing the electrolyzer makes it possible to create an overpressure of anode gas and determine its quantitative and chemical composition. Processing hafnium cathode sludge with potassium carbonate solution preserves the potassium cycle in the system and eliminates the effluents generated by ammonium carbonate. [ABSTRACT FROM AUTHOR]

In this work, the Keggin-type tri- and mono-palladium-substituted silicotungstates (POMs) were constructed by the reaction of tri- and monovacant silicotungstates ([SiW9O34]10− or [SiW11O39]8−) with palladium chloride. The as-obtained potassium salts of POMs demonstrated that Pd2+ ions were incorporated into POM frameworks. Notably, Pd nanoparticles were formed when the tri-palladium-substituted Keggin-type POM salts were reduced by H2. It was found that [SiW9O34]10− anions could act as multivacant coordination ligands to effectively stabilize palladium nanoparticles. The Pd nanoparticles were catalytically active for the reductive amination of carbon dioxide, and the formylamides were achieved in high yields under mild reaction conditions with methanol as the solvent. Notably, the Pd nanocatalyst exhibited outstanding recyclability and was recycled at least eight times without any obvious loss of the catalytic activity. The characterization by HAADF-STEM revealed that Pd nanoparticles formed a stable structure with POMs. Further studies demonstrated that the N-formylation reaction proceeds by the "methyl formate" pathway, involving CO2 activation by an in situ reaction with methanol and K2CO3 to generate potassium methyl carbonate. H2 underwent heterolytic dissociation with the assistance of a base over a Pd0–SiW9 catalyst, leading to one proton bound to carbonates and the hydride on a Pd atom (Pd–H). Moreover, the coupling of potassium methyl carbonate and Pd–H species afforded methyl formate intermediates in methanol, and then the reaction of methyl formate with amines gave formamides. This catalytic system demonstrated the benefits of excellent reactivity, stability, and recyclability for the N-formylation reaction. [ABSTRACT FROM AUTHOR]

In this work, the Keggin-type tri- and mono-palladium-substituted silicotungstates (POMs) were constructed by the reaction of tri- and monovacant silicotungstates ([SiW9O34]10− or [SiW11O39]8−) with palladium chloride. The as-obtained potassium salts of POMs demonstrated that Pd2+ ions were incorporated into POM frameworks. Notably, Pd nanoparticles were formed when the tri-palladium-substituted Keggin-type POM salts were reduced by H2. It was found that [SiW9O34]10− anions could act as multivacant coordination ligands to effectively stabilize palladium nanoparticles. The Pd nanoparticles were catalytically active for the reductive amination of carbon dioxide, and the formylamides were achieved in high yields under mild reaction conditions with methanol as the solvent. Notably, the Pd nanocatalyst exhibited outstanding recyclability and was recycled at least eight times without any obvious loss of the catalytic activity. The characterization by HAADF-STEM revealed that Pd nanoparticles formed a stable structure with POMs. Further studies demonstrated that the N-formylation reaction proceeds by the "methyl formate" pathway, involving CO2 activation by an in situ reaction with methanol and K2CO3 to generate potassium methyl carbonate. H2 underwent heterolytic dissociation with the assistance of a base over a Pd0–SiW9 catalyst, leading to one proton bound to carbonates and the hydride on a Pd atom (Pd–H). Moreover, the coupling of potassium methyl carbonate and Pd–H species afforded methyl formate intermediates in methanol, and then the reaction of methyl formate with amines gave formamides. This catalytic system demonstrated the benefits of excellent reactivity, stability, and recyclability for the N-formylation reaction. [ABSTRACT FROM AUTHOR]

In this study, the preparation of the composite material consisting of expanded vermiculite (EV) and potassium carbonate (K2CO3) was conducted using a solution impregnation method. Sorption and desorption experiments were undertaken to investigate the dynamic and thermodynamic properties of the EV/K2CO3 composites with varying salt contents. The findings suggest that the EV/K2CO3 composites effectively address the issues of solution leakage resulting from the deliquescence and excessive hydration of pure K2CO3 salt, thereby substantially improving the water sorption capacity and overall stability of the composite materials. The salt content plays a vital role in the sorption and desorption processes of EV/K2CO3 composites. As the salt content rises, the resistance to sorption mass transfer increases, resulting in a decline in the average sorption rate. Concurrently, as the salt content increases, there is a corresponding increase in the average desorption rate, water uptake, and heat storage density. Specifically, at a temperature of 30 °C and a relative humidity of 60%, the EVPC40 composite with a salt content of 67.4% demonstrates water uptake, mass energy density, and volumetric energy density values of 0.68 g/g, 1633.6 kJ/kg, and 160 kWh/m3, respectively. In comparison to pure K2CO3 salt, the utilization of EV/K2CO3 composites under identical heat demand conditions results in a 57% reduction in the required reaction material. This study offers essential empirical evidence and theoretical backing for the utilization and development of EV/K2CO3 composites within thermochemical energy storage systems. [ABSTRACT FROM AUTHOR]

Gamma-alumina (γ-Al2O3) is an essential support material in dry sorbents used to capture CO2 from flue gas. This study explores the deactivation of potassium-based γ-Al2O3 sorbents due to by-products such as KAl(CO3)(OH)2 during CO2 capture. We synthesized sorbents with K2CO3 loadings of 5, 10, 20, and 30 wt% and subjected them to repeated capture and regeneration cycles. The results show significant variations in the deactivation degree: the sorbent with 5 wt% K2CO3 exhibited a 100% deactivation rate, while the 30 wt% variant showed a markedly reduced rate of 44.6%. These findings highlight the impact of the formation of KAl(CO3)(OH)2 at the interface between K2CO3 and γ-Al2O3 on sorbent deactivation. An equation that can be used to predict the final CO2 capture capacity based on the ratio of active material to support was proposed using these results. [ABSTRACT FROM AUTHOR]

A photochemical synthesis of biologically relevant benzyl oxindoles is presented via electron‐donor acceptor (EDA) complex strategy. This exogenous photocatalyst‐free method describes the formation of a new electron donor‐acceptor complex based on potassium carbonate and thianthrenium salts for C(sp2)−C(sp3) bond formation. This transition‐metal free reaction allows a rapid increase in oxindoles molecular complexity chemical space, tolerating different functional groups as well as sophisticated biomolecules. The scalability and sustainability of this method is highlighted by an important waste recovery protocol. Mechanistic investigations support the formation of an EDA complex that induces a radical chain, and the applicability of this method is showcased by straightforward derivatization reactions. [ABSTRACT FROM AUTHOR]

The reaction of ethyl pyridine-2-ylcarbamate with phenacyl bromides in acetonitrile gave 2-aryl-1-(ethoxycarbonyl)-2-hydroxy-2-phenyl-2,3-dihydro-1H-imidazo[1,2-a]pyridine-4-ium bromides which were con--verted into 2-arylimidazo[1,2-a]pyridines by heating in acetic anhydride, followed by treatment with potassium carbonate. [ABSTRACT FROM AUTHOR]

Three novel trifluoromethylated compounds were designed and synthesized by reacting trifluoroacetimidoyl chloride derivatives with acetamidine hydrochloride or thiourea in the presence of potassium carbonate or sodium hydrogen carbonate as a base. In vitro and in vivo assays demonstrated the efficacy of the tested compounds in controlling root-knot nematode disease on pistachio rootstocks caused by Meloidogyne incognita. Bis-trifluoromethylated derivatives, namely N,N"-thiocarbonylbis(N'-(3,4-dimethylphenyl)-2,2,2-trifluoroacetimidamide) (compound A1), showed high efficacy as novel and promising nematicides, achieving up to 78.28% control at a concentration of 0.042 mg/liter. This effect is attributed to four methyl and two trifluoromethyl groups. In the pre-inoculation application of compound A1, all three concentrations (0.033, 0.037, and 0.042 mg/liter, and Velum) exhibited a higher level of control, with 83.79, 87.46, and 80.73% control, respectively. In the microplot trials, compound A1 effectively reduced population levels of M. incognita and enhanced plant growth at a concentration of 0.037 mg/liter. This suggests that compound A1 has the potential to inhibit hedgehog protein and could be utilized to prevent the progression of root-knot disease. Furthermore, the molecular docking results revealed that compounds A1 and A3 interact with specific amino acid residues (Gln60, Asp530, Glu70, Arg520, and Thr510) located in the active site of hedgehog protein. Based on the experimental findings of this study, compound A1 shows promise as a lead compound for future investigations. [ABSTRACT FROM AUTHOR]

This study aims to develop an efficient and green one-pot method for the synthesis of 6-en-1-yl furan-2-carboxylic acid heptyl ester. Initially, using furfural as the starting substrate, hept-6-en-1-yl furan-2-carboxylate was prepared using a one-pot method. This study developed a new experimental scheme for preparing ester compounds, using cuprous chloride as a catalyst and tert butyl hydrogen peroxide as an oxidant to prepare furoic acid. Without the need for intermediate treatment, the target product can be directly obtained from furfural by adding 7-bromo-1-heptene, TBAB, and potassium carbonate. This method effectively utilizes furfural as a platform chemical, demonstrating its potential for synthesizing high-value chemicals. The entire synthesis process is simple and efficient, following the principles of green chemistry. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to develop and evaluate a lateral flow card for the detection of active Schistosoma haematobium infection. Methods: In order to prepare the immunochromatography lateral flow strip (ICLFS), antibodies purified from schistosomiasis were conjugated passively with gold nanoparticles using a potassium carbonate buffer. Results: The novel ICLFS was able to correctly identify 64 out of 67 samples of schistosomiasis, 6 out of 90 samples of other parasites, and 0 out of 27 control samples. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were 95.5%, 93.3%, 90%, and 91.4% respectively. Comparatively, the sensitivity, specificity, NPV, and PPV of sandwich enzyme-linked immunosorbent assays (ELISA) conjugated with gold nanoparticles (AuNPs) were 91.1%, 88.8%, 85.9%, and 84.4% respectively. The increased sensitivity and specificity of ICLFS produced superior results to those of sandwich ELISA. Conclusion: In conclusion, ICLFS is more beneficial and precise than sandwich ELISA for detection of S. haematobium infection at early stage. [ABSTRACT FROM AUTHOR]

2D porous carbon materials have demonstrated immense potential in electrochemical energy storage, whereas the challenge of achieving their efficient preparation remains substantial. Herein, 2D carbon materials with high specific surface area (SSA), well‐developed porous structures, and controllable carbon layer thickness are successfully prepared by direct co‐pyrolysis of agroforestry biomass with potassium oxalate. It is found that the potassium oxalate acts as reactant and its decomposition product potassium carbonate acts as in situ template and activator. The potassium carbonate in the core activates the outer carbon structure to form nanopores, and regulates the thickness and the graphitization degree of the carbon material. Moreover, the N‐doping strategy seriously affects the structure of the materials. CSAN‐800 prepared with 0.2 vol.% NH3 addition can achieve N doping and SSA improvement (1802 m2 g−1) without damaging the ultra‐thin 2D structure. As a cathode material of sodium ion capacitors, CSAN‐800 exhibits excellent electrochemical with particularly a high‐capacity retention (90.3%) achieved (0.1 A g−1–2 A g−1). The 2D porous structure, high SSA, and rich pyridine‐N content significantly enhance the ion transport, storage, and optimize the charge carrier's adsorption and desorption. This study provides a low‐cost and eco‐friendly preparation strategy for ultra‐thin 2D porous carbon materials. [ABSTRACT FROM AUTHOR]

The postharvest antifungal activity of potassium carbonate (PC) against crown rot (CR) was investigated in banana cv. Enano Gigante by artificially inoculating with Colletotrichum musae (Cm) and incubating at 25 ± 1°C for 7 days. PC treatments were tested by in vitro and in vivo primary experiments. The in vivo preliminary concentration of 175 mM PC was selected as the most effective and was used in subsequent experiments on the influence of dip temperature on the effectiveness of PC. Curative dip treatments of 175 mM PC at 40°C for 20 min applied alone or combined with low doses of thiabendazole (TBZ) were evaluated on CR. Finally, the effect of PC on banana fruit quality was determined. PC at 150 and 200 mM totally inhibited mycelial growth and conidial germination of Cm. In in vivo primary experiments, 175 mM PC significantly reduced both the incidence (33.3% reduction) and the severity (90.5% reduction) of CR, but only in curative treatments. When the 175 mM PC dip for 20 min was tested at different temperatures, the curative dip at 40°C was the most effective, reducing CR incidence and severity by 91.6% and 98.8%, respectively, and was used for subsequent experiments. PC combined with TBZ at 225 μL L−1 did not improve the curative control effectiveness on CR compared to PC alone. PC did not affect the quality of banana fruit. [ABSTRACT FROM AUTHOR]

Direct air capture (DAC) of CO2 is an important technology to mitigate mobile carbon emissions, reduce atmospheric CO2 concentration, and cope with climate change. Moisture‐swing adsorption is regarded as one of the most promising technologies in DAC due to its low energy consumption and ease of operation. In this work, a cheap and easily available moisture‐swing adsorbent of potassium carbonate loaded on porous supports (i.e., activated carbon, magnesium oxide, and zeolite) was prepared for CO2 capture from ambient air. The composite adsorbent of potassium carbonate on activated carbon showed the best performance with a DAC capacity of 0.562 mmol/g at 25°C and 5% relative humidity. The effects of temperature, relative humidity, and CO2 concentration on the adsorption performance were investigated systematically, as well as the cyclic DAC performance. In 50 adsorption–desorption cycles, the adsorption capacity of the composite adsorbent decreased by ~40% due to potassium carbonate leaching loss during water evaporation but can be fully recovered simply by re‐impregnating with potassium carbonate again. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to provide a salt ready-mix to instant fried noodles manufacturers. Design/methodology/approach: Response surface methodology was used to get optimized salt ready-mix based on carbonate salt, disodium phosphate, tripotassium phospahte, sodium hexametaphosphate and sodium chloride. Peak viscosity of flour and yellowness, cooking loss and hardness of noodles were considered as response factors for finding optimized salt formulation. Findings: The results showed that salts have an important role in governing quality of noodles. Optimum levels of five independent variables of salts, namely, carbonate salt (1:1 mixture of sodium to potassium carbonate), disodium phosphate, sodium hexametaphosphate, tripotassium phosphate and sodium chloride were 0.64%, 0.29%, 0.25%, 0.46% and 0.78% on flour weight basis, respectively. Originality/value: To the best of the authors' knowledge, this is the first study to assess the effect of different combinations of different salts on the quality of noodles. These findings will also benefit noodle manufacturers, assisting in production of superior quality noodles. [ABSTRACT FROM AUTHOR]

Managing plastic waste containing polyvinyl chloride is difficult due to the release of hazardous substances such as hydrogen chloride. Alkaline metal has been proven to minimize the release of hydrogen chloride during thermal degradation of polyvinyl chloride. However, most past studies conducted heating experiments under a high temperature which promotes the production of aromatic hydrocarbons. In this study, low‐temperature pyrolysis was utilized which focuses on the dehydrochlorination stage while minimizing further degradation of hydrocarbons. The effectiveness of calcium oxide, calcium carbonate and potassium carbonate in minimizing the release of hydrogen chloride was also evaluated. Among those three additives, calcium oxide and potassium carbonate have shown some potential in uptaking hydrogen chloride. Especially when the molar ratio of additive to PVC is 1:1.6, calcium oxide reduced the generation of hydrogen chloride to as low as 20%. Potassium carbonate also exhibits an uptake effect but has a slight catalytic effect when the molar ratio is less than 1:1. On the other hand, calcium carbonate not only shows little to no uptake effect, but also promotes the thermal degradation of hydrocarbon. [ABSTRACT FROM AUTHOR]

The occurrence of buetschliite, K2Ca(CO3)2, as inclusions in mantle minerals, is considered as one of the keys to understanding phase relationships of dense carbonates and outlines the potential role of potassium carbonates in the Earth's deep carbon cycle. Within this scope, the high‐pressure behavior of synthetic buetschliite is characterized by in situ Raman spectroscopy up to 19 GPa and 300°C. Up to 6 GPa, the compression is regular, then the splitting of some of the lattice and internal modes defines the transition to a low‐symmetry phase, in analogy to that observed previously in K2Mg(CO3)2. The temperature rise to 300°C shifts the transition pressure from ~6 to ~8 GPa, but on the whole, it does not change the high‐pressure behavior of K2Ca(CO3)2. The observed pressure‐induced spectral changes are fully reversible at room and elevated temperature. The findings show the expansion of buetschliite baric stability with temperature, which confirms its importance as a constituent of carbonate inclusions in deep minerals. [ABSTRACT FROM AUTHOR]

The application of commonly used flame retardants in most cases causes reduction in strength characteristic of particleboard. Therefore, it was decided to carry out research aimed at determining possibility of using pMDI-reinforced PF adhesive to produce board with increased fire resistance. The effect of different shares of particles impregnated with a mixture of potassium carbonate and urea on the particleboard properties such as density, density profile, bending strength, modulus of elasticity, internal bond and internal bond after boiling was investigated. Presented work also determined the effect of fire retardant on the performance of particleboards after ageing test and their reaction to fire. Studies demonstrated that PF adhesive modified with 20% pMDI is suitable for gluing impregnated wood particles. Regardless of their share, resultant panels showed no changes in strength and density. In the case of boards consisting of impregnated particles in the amount of 75% and 100%, lower values of swelling were demonstrated. The boards were classified as load-bearing boards for use in humid conditions. Fire retarding efficiency was confirmed by lowered mass loss, prolonged time needed to reach maximal burning rate, decreased gross calorific value and reduced ignitability when exposed to both radiant heat source and small flame source. [ABSTRACT FROM AUTHOR]

The present study was conducted to determine and analyse the content of furosine, acrylamide and furan in fermented cocoa beans from the Chuao ("criollo variety") and Barlovento ("trinitario variety") regions of Venezuela, after roasting (in the shell at 110–180 °C for 15–60 min) and alkalisation (with sodium bicarbonate or potassium carbonate, at concentrations of 10–25 g/kg in order to evaluate the impact of these operations. The highest furosine contents (up to 249 mg/100 g of protein) were found in fermented, sun-dried samples, and were higher in the nibs than in the shells. The acrylamide content increased in line with the temperature, to 160 °C in the shells, and to 180 °C in the nibs. At temperatures of up to 140 °C, the acrylamide content was higher in the shells than in the nibs. The furan content increased in line with the temperature and in this case too, was greater in the shells. The content of both furosine and furan decreased with alkalisation, while the presence of acrylamide was irregular and determined by the roasting temperature and the alkalising agent employed. Although the furosine, acrylamide and furan contents varied between the beans from the two regions and the varieties considered (Chuao and Barlovento), these three compounds were correlated to a statistically significant degree. [ABSTRACT FROM AUTHOR]

An asymmetric transfer hydrogenation of 2‐oxazolones in the presence of a chiral diamine ruthenium catalyst with potassium formate as a hydrogen source and potassium carbonate as an additive in 2,2,2‐trifluoroethanol is described. A series of chiral 2‐oxazolidinones were obtained with 29%–95% yields and 86%–>99% ee's. Furthermore, gram‐scale synthesis of chiral 2‐oxazolidinone and its downstream derivatizations demonstrate the practicality of this method. [ABSTRACT FROM AUTHOR]

In this study, we introduce a new protocol for the synthesis of tetracyclic acridone derivatives using a benzylation reaction under microwave irradiation. Compared to traditional approaches, our protocol is significantly more effective, takes far less time and is also in accordance with the principles of green chemistry. Under the solvent-free conditions, the benzylation reaction was performed between acridone (1 eq) and benzyl bromide (1 eq) in the presence of potassium carbonate (1.5 eq) under microwave irradiation. The reaction was completed within 3 min, resulting in higher yields of the products, up to 96%. It has been observed that the developed protocol is best suited for the N-benzylation of acridone with different benzyl halides. [ABSTRACT FROM AUTHOR]

The loss of quality of wolframite concentrates determines the need to improve their processing method that ensures maximum conversion of tungsten into water-soluble wolframate and a reduction in water-soluble impurities. The results of thermodynamic modeling of the sintering of wolframite concentrate with sodium and potassium carbonates indicate a greater efficiency of K2CO3: The reagent consumption required for complete conversion of tungsten into solution decreases from 170% from stoichiometric sintering with Na2CO3 to 110% for K2CO3, as well as the proportion of soluble silicates up to 0.1%. In addition, sintering with K2CO3 is accompanied by the formation of compounds with a higher melting point, preventing melting and coating formation during the process. Mathematical sintering models were obtained by the method of probabilistically deterministic planning of this experiment. Optimal parameters have been determined: The extraction of tungsten into a solution of more than 95% is achieved by sintering with K2CO3 in an amount of 105–110% according to the stoichiometric requirements for the formation of K2WO4, K2MoO4, and K2SO4 at temperatures of 1073–1123 K for 100–120 min. Pilot tests have confirmed the effectiveness of the process. The possibility of sintering a cinder of wolframite concentrate with K2CO3 without the introduction of recycled materials has been established. Sintering under optimal conditions ensures the transition of tungsten to water-soluble tungstate by 97.5%.

A novel and cost-effective heterogeneous catalyst for glycerol carbonate production through transesterification was developed by impregnating smectite clay with K2CO3. Comprehensive structural and chemical analyses, including X-ray diffraction Analysis (XRD), Scanning Electron Microscopy (SEM)-Electron Dispersion Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) surface area analysis measurements, were employed to characterize the catalysts. Among the various catalysts prepared, the one impregnated with 40 wt% K2CO3 on smectite and calcined at 550 °C exhibited the highest catalytic activity, primarily due to its superior basicity. To enhance the efficiency of the transesterification process, several reaction parameters were optimized, including the molar ratio between propylene carbonate and glycerol reactor loading of the catalyst and reaction temperature. The highest glycerol carbonate conversion rate, approximately 77.13% ± 1.2%, was achieved using the best catalyst under the following optimal conditions: 2 wt% reactor loading, 110 °C reaction temperature, 2:1 propylene carbonate to glycerol molar ratio, and 6h reaction duration. Furthermore, both the raw clay and the best calcined K2CO3-impregnated catalysts demonstrated remarkable stability, maintaining their high activity for up to four consecutive reaction cycles. Finally, a kinetic analysis was performed using kinetic data from several runs employing raw clay and the most active K2CO3-modified clay at different temperatures, observing that a simple reversible second-order potential kinetic model of the quasi-homogeneous type fits perfectly to such data in diverse temperature ranges. [ABSTRACT FROM AUTHOR]

Background: Multidrug resistance-associated protein 1 (MRP1), an energy-dependent efflux pump, is expressed widely in various tissues and contributes to many physiological and pathophysiological processes. 6-Bromo-7-[11C]methylpurine ([11C]7m6BP) is expected to be useful for the assessment of MRP1 activity in the human brain and lungs. However, the radiochemical yield (RCY) in the synthesis of [11C]7m6BP was low, limiting its clinical application, because the methylation of the precursor with [11C]CH3I provided primarily the undesired isomer, 6-bromo-9-[11C]methylpurine ([11C]9m6BP). To increase the RCY of [11C]7m6BP, we investigated conditions for improving the [11C]7m6BP/[11C]9m6BP selectivity of the methylation reaction. Results: [11C]7m6BP was manually synthesized via the methylation of 6-bromopurine with [11C]CH3I in various solvents and at different temperatures in the presence of potassium carbonate for 5 min. Several less polar solvents, including tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), and ethyl acetate (AcOEt) improved the [11C]7m6BP/[11C]9m6BP selectivity from 1:1 to 2:1, compared with the conventionally used solvents for the alkylation of 6-halopurines, acetone, acetonitrile, and N,N-dimethylformamide. However, a higher temperature (140 °C or 180 °C) was needed to progress the 11C-methylation in the less polar solvents, and the manual conditions could not be directly translated to an automated synthesis. [11C]Methyl triflate ([11C]CH3OTf) was thus used as a methylating agent to increase the conversion at a lower temperature. The 11C-methylation using [11C]CH3OTf at 100 °C proceeded efficiently in THF, 2-MeTHF, and AcOEt with maintenance of the improved selectivity. Starting from 28 to 34 GBq [11C]CO2, [11C]7m6BP was produced with 2.3–2.6 GBq for THF, 2.7–3.3 GBq for AcOEt, and 2.8–3.9 GBq for 2-MeTHF at approximately 30 min after the end of bombardment (n = 3 per solvent). The isolated RCYs (decay corrected) for THF, 2-MeTHF, and AcOEt were 24–28%, 29–35%, and 22–31% (n = 3), respectively. Conclusions: The use of THF, 2-MeTHF, and AcOEt improved the [11C]7m6BP/[11C]9m6BP selectivity in the methylation reaction, and the improved method provided [11C]7m6BP with sufficient radioactivity for clinical use. [ABSTRACT FROM AUTHOR]

The marine natural product norzooanemonin (1,3-dimethylimidazolium-4-carboxylate) has been used to prepare a series of carboxyl- or carboxylate-functionalized N-heterocyclic carbene (NHC) gold(I) complexes from [(Me2S)AuCl] in the presence of potassium carbonate. The potential of the resulting mono- and dicarbene complexes to act as cytotoxic or antibacterial drugs was investigated. [ABSTRACT FROM AUTHOR]

The catalytic effect of alkali metal carbonates, in situ generated carbene, and anionite in the transesterification reaction of alkyl benzoates with methanol, ethanol, benzyl alcohol, and cyclohexanol, as well as vegetable oils with methanol and ethanol was studied. Catalytic reactions with methanol occur at room temperature with yields close to quantitative. The reactions of the vegetable oils in the presence of potassium carbonate with small amounts of methanol or ethanol (3.2 eq) at room temperature lead to high yields of biodiesel fuel and are suitable for industrial use. [ABSTRACT FROM AUTHOR]

A method for the regioselective synthesis of imidazo[4,5‐e][1,3]thiazino[2,3‐c][1,2,4]triazine derivatives has been developed by the reaction of imidazotriazinethiones with ethyl phenylpropiolate upon treatment with potassium carbonate or sodium methoxide in methanol. The synthesis was accomplished by Michael‐type addition of the imidazotriazinethiones to the triple bond of ethyl phenylpropiolate followed by subsequent intramolecular cyclization. [ABSTRACT FROM AUTHOR]

Understanding the impact of pre-treatment methods on the phytochemical composition of grapes is essential for optimizing grape quality and producing raisins with desirable characteristics. Therefore, this study meticulously analyzed the impact of two distinct pre-treatment methods, oak ash and potassium carbonate (K2CO3), on the composition of essential phytochemical components in grapes. This research encompassed phenolic compounds, anthocyanins, phenolic acids, flavonoids, and phytoalexins. This study investigates the impact of pre-treatment methods, oak ash and K2CO3, on the phytochemical composition of grapes. Significant differences were observed in anthocyanins, flavonoids, phytoalexins, and phenolic acids between the treatments. Oak ash exhibited advantages in preserving specific compounds, including higher levels of anthocyanins, flavonols, flavones, flavanones, catechins, resveratrol, pterostilbene, and viniferin, compared to K2CO3. Notably, the delphinidin-3-O-glycoside content was significantly higher in the oak ash treatment. An analysis of phenolic compounds revealed distinctions in hydroxycinnamic acids, hydroxybenzoic acids, benzaldehyde, and phenylacetaldehyde. Additionally, gallic acid, vanillic acid, trans-caffeic acid, trans-p-coumaric acid, and (-)-epicatechin were significantly more prevalent in the K2CO3 treatment, while ferulic acid and quercetin were more prevalent in the oak ash treatment. These findings underscore the pivotal role of pre-treatment methods in shaping the phytochemical content of grapes, thus holding critical implications for grape-derived products' quality and potential health benefits. [ABSTRACT FROM AUTHOR]