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Context: Nickel-catalyzed hydroamination of dienes with phenylmethanamines was studied theoretically to investigate reaction mechanism. These calculated results revealed that Ni-catalyzed hydroamination began with the O − H bond activation of trifluoroethanol, including three important elementary steps: the ligand-to-ligand hydrogen migration, the nucleophilic attack of phenylmethanamine, and hydrogen migration. The nucleophilic attack of phenylmethanamine was the rate-determining step, and the branched product of 3,4-addition with (S)-chirality was the most dominant. The N − H bond activation of phenylmethanamine occurred more difficultly than the O − H bond of trifluoroethanol, because of high ΔG and ΔG≠. In addition, the origin of regioselectivity and enantioselectivity, and prediction of the ligand were also discussed in this text. Methods: All computations were performed with Gaussian09 program. All geometries were optimized at the ωB97XD/6-31G(d,p) level (SDD for Ni), and to obtain more accurate potential energy, single-point calculation was carried out at the ωB97XD/cc-pVDZ level (SDD for Ni). The Cramer-Truhlar continuum solvation model (SMD) was used to evaluate solvation effect of mesitylene, and a correction of the translational entropy was made with the procedure of Whitesides group. [ABSTRACT FROM AUTHOR]

The chemistry of bidentate ligands with a dppf-like motif, where phosphorus is fully or partially replaced by other pnictogens as donor sites, is summarized and discussed in this comprehensive review, while covering the literature from 1966 to 2024, related to more than 165 original references and discussing more than 75 independent chemical entities (1–41). Besides addressing synthetic, structural, and electrochemical aspects of such compounds, their donor properties and metal coordination behavior is discussed, along with catalytic applications. Based on their electronic and steric situations, trends in the performance of such compounds, either as ligands for catalysis or on their own merits for non-catalytic purposes, have been elucidated. Related topics that could not be covered in this article have been acknowledged by referring to the literature for completeness. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of monovalent and divalent ions and the dosage of a SiO2-based nanocomposite on the thermochemical stability of HPAM polymeric solution. Chelating amine–functionalized NPs (AFNPs) were used to enhance the thermochemical stability of HPAM based on capturing monovalent/divalent ions after seven days at 70°C. Different polymer solutions prepared with calcium chloride dihydrate (CaCl2·2H2O) at 2000 mg/L and sodium chloride (NaCl) at 10000 mg/L, and two different dosages of HPAM (1000 and 2000 mg/L) were assessed in the presence and absence of AFNPs at dosages of 200, 500 and 1000 mg/L. The nanocomposite was characterized by N2 adsorption, Fourier-transformed infrared spectrophotometry (FTIR), thermogravimetric analysis (TGA), dynamic Light Scattering (DLS), and Zeta potential (ZP). Stability tests over time confirmed the positive effect of nanocomposite on increasing the thermochemical stability of polymer solutions. Results revealed that adding 0, 200, and 500 mg/L of nanocomposite to the polymeric solution at 1000 mg/L of HPAM, 10000 mg/L of NaCl, and 2000 mg/L of CaCl2·2H2O led to the viscosity reductions of 73.5%, 18%, and less than 1% after 7 days (70°C), respectively. Nanocomposite at 200 mg/L reduces the polymer degradation in the presence of the two salts evaluated separately, i.e., 20% for 10000 mg/L of NaCl and 15% for 2000 mg/L of CaCl2·2H2O. The adsorption tests on AFNPs and SiO2 NPs concluded that AFNPs had higher adsorption of cations in comparison to SiO2 NPs and that greater adsorption of cations is related to a reduction in polymer degradation.

Treatment of various (R)-N-(2,2,3,3-tetrafluoropent-4-en-1-ylidene)-1-phenylethylamine derivatives with 2.4 equiv of DBU in toluene at room temperature to 50 °C for 24 h led to a smooth [1,3]-proton shift reaction with a high chirality transfer, affording the corresponding rearranged products in acceptable yields. Without purification, these products were subjected to acid hydrolysis and the subsequent N-Cbz protection, providing the optically active tetrafluoroethylenated amides in moderate three-step yields.

Abstract This study developed a novel and highly active heterogeneous catalyst of nickel nanoparticles supported on β-cyclodextrin-grafted magnetic Fe3O4 nanoparticles (Ni@β-CD@Fe3O4). β-CD, a biodegradable, biocompatible, green, and non-toxic cyclic oligosaccharide, was modified with Fe3O4 nanoparticles to create β-CD@Fe3O4. The nickel was then immobilized onto this support. The catalyst was characterized using FT-IR, XRD, TEM, AAS, FE-SEM, TGA, EDX, DRS-UV-Vis spectra, and VSM techniques. The catalytic activity of Ni@β-CD@Fe3O4 was evaluated for the reduction of nitroarene compounds in water at 25 ℃. This nanocatalyst indicated great activity and selectivity in reducing various nitroarenes, including nitrobenzene, nitroaniline, nitrotoluene, and nitrophenol derivatives. Additionally, the catalyst showed significant reusability and could be easily separated using an external magnet, highlighting its potential for green chemistry and sustainable industrial applications.

Coordination compounds of polydentate nitrogen ligands with metals are used extensively in research areas such as catalysis, and as models of complex active sites of enzymes in bioinorganic chemistry. Tris(2-pyridylmethyl)amine (TPA) is a tripodal tetradentate ligand that is known to form coordination compounds with metals, including copper, iron and zinc. The related compound, tris[(6-bromopyridin-2-yl)methyl]amine (TPABr3), C18H15Br3N4, which possesses a bromine atom on the 6-position of each of the three pyridyl moieties, is also known but has not been heavily investigated. The molecular structure of TPABr3 as determined by X-ray diffraction is reported here. The TPABr3 molecule belongs to the triclinic, P\overline{1} space group and displays interesting intermolecular Br...Br interactions that provide a stabilizing influence within the molecule.

Silica and silicate scale deposition in the production systems resulted in reduced production rates and equipment damages. Chemical scale inhibition using squeeze method is advantageous for petroleum reservoir conditions. This paper aims to assess the adsorption and squeeze performance of developed scale inhibitors that consist of polyamidoamine (PAMAM) dendrimers and pteroyl-L-glutamic acid (PGLU). Commercial inhibitor, diethylenetriamine penta(methylene phosphonic acid), also known as DETPMP, was also used to benchmark the laboratory findings. Static adsorption test and core flooding were performed to investigate the adsorption characteristics and retention of the inhibitors in Berea sandstone cores. Simulation was also conducted to estimate the squeeze performance of the inhibitors. Results revealed that PAMAM-2-PGLU scale inhibitor exhibited the highest adsorption and retention in the sandstone core. The treatment of PAMAM-2-PGLU and PAMAM-1-PGLU inhibitors increased the core permeabilities. SQUEEZE IV model predicted that both PAMAM-PGLU inhibitors yielded longer squeeze lifetime than DETPMP inhibitor. Both experimental and simulation results showed good fit in terms of adsorption and squeeze lifetime. In this paper, the tested PAMAM-PGLU scale inhibitors have demonstrated better adsorption, retention, and squeeze lifetime in sandstone formation. They could offer effective and low-toxicity alternatives to commercial inhibitors due to raising environmental concerns.

Purine stretches, sequences of adenine (A) and guanine (G) in DNA, play critical roles in binding regulatory protein factors and influence gene expression by affecting DNA folding. This study investigates the relationship between purine stretches and cancer development, considering the aromaticity of purines, quantified by methods like Hückel's rule and NICS calculations, and the importance of the flanking sequence context. A pronounced avoidance of long purine stretches by typical cancer mutations was observed in public data on the intergenic regions of cancer patients, suggesting a role of intergenic sequences in chromatin reorganization and gene regulation. A statistically significant shortening of purine stretches in cancerous tumors (p value < 0.0001) was found. The insights into the aromatic nature of purines and their stacking energies explain the role of purine stretches in DNA structure, contributing to their role in cancer progression. This research lays the groundwork for understanding the nature of purine stretches, emphasizing their importance in gene regulation and chromatin restructuring, and offers potential avenues for novel cancer therapies and insights into cancer etiology. [ABSTRACT FROM AUTHOR]

This study aims to analyze the degradation behavior and mechanisms of amine-cured epoxy asphalt (EA) under the combined effects of ultraviolet (UV) radiation, oxygen, and temperature. To achieve this, amine-cured epoxy resin (ER) and EAs containing 35%, 45%, and 55% asphalt content were prepared and subjected to simulated UV-based aging. Various analytical techniques were employed to investigate the mechanical properties, microstructure, morphology, and oxidation layer of ER and EAs. The results indicate that after UV-based aging, ER and EAs with 35%–45% asphalt content experienced an increase in mass, a decrease in strength and glass transition temperature. In comparison, EAs with 55% asphalt content exhibited the opposite trends. The elongation and (Tanδ)max of ER and EAs reduced, whereas the storage modulus and hardness at mid to high temperatures rose. At the microstructural level, the degradation of the resin phase was confirmed by changes in ether, ester, and amide groups, whereas the generation of sulfoxide groups was associated with the oxidation of the asphalt phase. Compared with ER, the surface of EA has obvious defects after aging, which is the main reason for the decrease in contact angle. As the asphalt content increases, EAs exhibit higher carbonyl concentration, more profound oxidation, and more obvious performance degradation. This trend suggests that the resin phase mitigates the aging of the asphalt phase by absorbing harmful UV radiation and oxygen. [ABSTRACT FROM AUTHOR]

Objectives: Reflecting the need for an effective support for the daily oral hygiene routine of patients experiencing (symptoms of) gum inflammation, a new mouthwash has been developed containing an amine + zinc lactate + fluoride system. The in vitro efficacy of this product was assessed using traditional laboratory methods, as well as novel experimentation. Materials and Methods: This mouthwash has been evaluated in a series of laboratory tests including two short interval kill tests (SIKTs), a 12‐h (longer term) biofilm regrowth assay, a plaque glycolysis assay, and an aerobic, repeated exposure biofilm model, as well as tests for soft tissue uptake and LPS neutralization. Results: Several laboratory studies demonstrate that a mouthwash containing an amine + zinc lactate + fluoride system provides short‐term and long‐term antibacterial activity. While the immediate efficacy of this formula has been shown to be driven by the presence of the amine, zinc lactate provides a long‐term antibacterial effect, as well as is able to inhibit bacterial metabolism. Conclusions: This research provides the basis for understanding the mode of action of this new mouthwash formulation and explains the previously observed clinical efficacy of this formula against plaque and gingivitis. [ABSTRACT FROM AUTHOR]

Amine-based carbon capture has proven to be a mature technology, but challenges remain. Emission control of potentially hazardous compounds is critical to ensure the long-term viability of the technology. The ability to predict which compounds to expect in gas emissions and at what levels is fundamental. This work aims to provide a qualitative and quantitative assessment of the volatility of both MEA and HS3 blend degradation products. VLE experiments were performed with different degraded solutions over a temperature range from 40 to 100 °C. Samples were analyzed using extensive LC-MS methods to quantify over 40 degradation compounds. Henry's constants were calculated to assess their volatility. The compiled results allow the ranking of most of the compounds studied in terms of volatility, and the quantification of their relative volatility compared to each other. Pyrazines and alkylamines are among the most volatile, followed by aldehydes, ketones, nitrosamines, and finally, larger amides. When compared, the volatilities of the degradation compounds are consistent from one degraded solution to another, highlighting the possibility of generalization from one solvent to another. This consistency is also observed with the dilute version of the degraded solutions simulating water-wash conditions. Finally, this work provides insight into the temperature dependence of the volatilities of the compounds studied. The methodology used provides a valuable and new type of data that have never been published before on the volatility of amine degradation compounds. The results can be used to better understand emissions and the design of emission control technologies.

Functional ionic liquids have been widely used in the fields of synthetic chemistry, analytical chemistry, electrochemistry and material chemistry owing to their excellent properties such as easy structure modification and adjustable properties. In this work, a series of basic functionalized ionic liquids were prepared from 1, 4-diazabicyclo [2.2.2] octane (DABCO) or hexamethylenetetramine (HMTA) with various halogenated hydrocarbons, then these functional ionic liquids and water were used as solvent-catalyst system in the Knoevenagel reaction of various aldehydes with ethyl cyanoacetate or malononitrile, the influence of the structure of the ionic liquid and the content of water was investigated. The results showed that the composite solvent-catalyst system mixed by the functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo [2.2.2] octane bromide with water can effectively promote the Knoevenagel reaction and the alkalinity of amine and hydrogen bond play an important role. Aromatic aldehydes with electron-donating or electron-withdrawing groups can obtain the target product at an excellent yield (79-99%). It is worth noting that the polycyclic aromatic aldehydes with high steric hindrance, 86%-95% yields of the object products were also obtained after 15 h-25 h. Furthermore, the catalyst could be reused for 6 times without any loss in its catalytic activity.The composite solvent-catalyst system mixed by the Functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo[2.2.2]octane bromide with water can effectively promote the Knoevenagel reaction, even for the electron-rich aromatic aldehydes with poor reactivity, high yields of the target products and fast reaction rate were also obtained at room temperature.

The study is dedicated to the investigation of the catalytic activity of zinc carboxylates in the condensation reaction of camphor with aliphatic diamines. The reaction of camphor with 1,6-hexanediamine was selected as the model system. The research demonstrated that the reaction does not proceed without a catalyst, while the use of zinc carboxylates as catalysts leads to a higher conversion and selectivity compared to the classical catalyst for this reaction, Et2O∙BF3. The best results were achieved using zinc 2-ethylhexanoate, which provided an 88.4 % conversion of camphor and a 76.9 % selectivity for the formation of diimine. It was established that the catalytic activity of zinc carboxylates in the condensation reaction of camphor with diamines is related to the structure of the acid residue of the salt. Based on the obtained data, a reaction mechanism was proposed, associated with the formation of a complex between the zinc carboxylate and the initial amine, which is confirmed by FTIR and UV–vis spectroscopic data.

In the title molecule, C21H17N3O2, the five-membered ring is slightly ruffled and dihedral angles between the pendant six-membered rings and the central, five-membered ring vary between 50.78 (4) and 86.78 (10)°. The exocyclic nitrogen lone pair is involved in conjugated π bonding to the five-membered ring. In the crystal, a layered structure is generated by O—H...N and N—H...O hydrogen bonds plus C—H...π(ring) and weak π-stacking interactions.

Absorption is the most widely used carbon dioxide (CO2) removal technology. The CO2 absorption performance of monoethanolamine (MEA), the most commonly used CO2 absorbent, can be improved by suspending nanoparticles. This work examined the performance of graphene nanoplatelets (GNPs) as additives to enhance CO2 absorption in MEA. The GNPs were characterized by HRTEM, FTIR, and XRD. The study examined the influence of GNP concentrations on CO2 absorption at room temperature. The images from HRTEM confirmed that the implemented graphene consists of several layers of graphene sheets. Increasing the loading of particles increased the solubility of CO2 until the optimum concentration was reached. From this work, it is evident that incorporating GNPs into MEA enhances the CO2 absorption performance of MEA. Thus, the addition of nanoparticles to the absorbent can enhance its CO2 absorptivity. [ABSTRACT FROM AUTHOR]

With the growing significance of green chemistry in organic synthesis, electrochemical oxidation has seen rapid development. Compounds undergo oxidation–reduction reactions through electron transfer at the electrode surface. This article proposes the use of electrochemical methods to achieve cleavage of the benzyl C–N bond. This method selectively oxidatively cleaves the C–N bond without the need for metal catalysts or external oxidants. Additionally, primary, secondary, and tertiary amines exhibit good adaptability under these conditions, utilizing water as the sole source of oxygen. [ABSTRACT FROM AUTHOR]

[Display omitted] Photocatalytic oxidative coupling of amines is considered a mild, efficient, and sustainable strategy for the synthesis of imines. As a versatile organic semiconductor, conjugated microporous polymers (CMPs) are attractive in photocatalysis areas due to the diversity of their polymeric monomers. Herein, we report that in addition to the design of monomers, size-confined polymerization is also a feasible strategy to modulate the structure and photocatalysis properties of CMPs. We adopted dibromopyrazine as polymeric units to prepare pyrazine-involved hollow spherical CMPs (H-PyB) using a template method and successfully performed size-confined polymerization of hollow samples by resizing the templates. Interestingly, the small confinement space induced the formation of CMPs with better conjugate extensibility, resulting in enhanced conductivity, narrowed bandgaps, improved photoelectric performance, etc. As a result, small-sized H-PyB CMPs had superior activity for the photocatalytic oxidation of amines. Particularly, the smallest H-PyB CMPs that we designed in the present work exhibited excellent performance for the photocatalytic coupling oxidation of amines. When using benzylamine as a model substrate, the yield of the corresponding imine reached ∼ 113 mmol·g−1·h−1, accompanied by almost 100 % selectivity. Furthermore, the as-designed confined samples exhibited stable photocatalytic activity as well as good applicability for oxidative coupling of different amines. This work not merely reports a kind of CMP photocatalysts with excellent performance for the imine coupling oxidation but also proposes an alternative strategy for constructing high-performance organic photocatalysts by size-confined synthesis. [ABSTRACT FROM AUTHOR]

The present work investigates the volumetric and viscometric properties of an aqueous solution of 1,2-dimethylethylenediamine (DEEDA) over an entire concentration range and an absorber operating temperature range of 313.15K-333.15K at atmospheric pressure. The investigated volumetric properties included the density, excess molar volume, partial molar volume, and the investigated viscometric properties included the viscosity, viscosity deviation, free energy for activation of viscous flow, excess free energy for activation of viscous flow, and excess entropy for activation of viscous flow. The results indicated that there are strong intermolecular interactions and suitable molecular packing in the binary DEEDAewater mixture. Hence, the mixture was found to deviate from a real mixture according to the calculated excess properties. The DEEDA solvent's preliminary volumetric and viscometric properties revealed convincing potential as a novel amine for carbon capture. Additionally, the Redlich-Kister-based correlations showed favorable correlative performance for excess molar volume, viscosity deviation, and excess entropy for activation of viscous flow. [ABSTRACT FROM AUTHOR]

This works documents a new silica gel-supported nanocatalyst (Si@NSBPdNPs 3) with low Pd loadings for n-alkylation reactions at room temperature. Post synthesis characterisation using SEM-EDX and ICP techniques provided a quantitative assessment of palladium species. Additionally, TEM analysis unveiled an average palladium nanoparticle size of 5.87 ± 0.2 nm. In-depth X-ray Photoelectron Spectroscopy (XPS) analysis revealed its predominant composition as Pd(0) complexed to a Schiff base ligand on low cost silica matrix. The nanocatalyst exhibited high efficacy in the catalysis of n-alkylation (Michael addition) reactions with various α,β-unsaturated Michael acceptors, yielding the corresponding n-alkyl products at room temperature with exceptional yields. Notably, the catalyst exhibited good stability and could be easily separated from the reaction mixture. Moreover, the catalyst displayed recyclability potential, maintaining its original catalytic efficacy for up to seven cycles without any discernible loss.

Abstract Objectives Reflecting the need for an effective support for the daily oral hygiene routine of patients experiencing (symptoms of) gum inflammation, a new mouthwash has been developed containing an amine + zinc lactate + fluoride system. The in vitro efficacy of this product was assessed using traditional laboratory methods, as well as novel experimentation. Materials and Methods This mouthwash has been evaluated in a series of laboratory tests including two short interval kill tests (SIKTs), a 12‐h (longer term) biofilm regrowth assay, a plaque glycolysis assay, and an aerobic, repeated exposure biofilm model, as well as tests for soft tissue uptake and LPS neutralization. Results Several laboratory studies demonstrate that a mouthwash containing an amine + zinc lactate + fluoride system provides short‐term and long‐term antibacterial activity. While the immediate efficacy of this formula has been shown to be driven by the presence of the amine, zinc lactate provides a long‐term antibacterial effect, as well as is able to inhibit bacterial metabolism. Conclusions This research provides the basis for understanding the mode of action of this new mouthwash formulation and explains the previously observed clinical efficacy of this formula against plaque and gingivitis.

Amine solvent processes are often confronted with the problem of foaming, which can lead to reduced amine efficiency in H2S and CO2 absorption. To this end, it is crucial to investigate the causes of foaming in amine systems and develop a procedure to effectively combat this problem. According to this research, the main causes of foaming in amine solutions are hydrocarbon condensate, suspended solids, amine degradation products, corrosion inhibitors and operating parameters. To prevent foaming in the scrubber, it is important to use filter coalescers, activated carbon, and precoat filters that can remove solid particles and hydrocarbon mists from the feed gas and amine solution. It is also recommended to maintain the amine inlet temperature at 5–10 °C above the dew point of the feed gas to prevent the hydrocarbons from condensing in the scrubber. Foaming can be significantly influenced by unsaturated fatty acids even in small amounts of 10 ppm in the amine solution. Acetic acid and octanoic acid are also notable amine degradation byproducts that can reduce foam volume by 25% and 23%, respectively. On the other hand, piperazine and bicine are other amine byproducts that can significantly impact the foam breaking time by 467% and 344%, respectively. To prevent amine degradation, it is recommended to maintain the temperature of the amine at 125–130 °C in the stripper and at 40–45 °C in the scrubber. To effectively manage and control foaming in amine solutions, a comprehensive procedure is advised to control and mitigate this issue. Lastly, future areas of research have been identified to address the problem of foam in amine systems.

The use of Liquid Organic Hydrogen Carriers (LOHC) is one of the potential options to store hydrogen. Today, the vast majority of compounds used as LOHC come from the oil industry. Using biosourced LOHC would be a step forward in the development of this CO2-free solution. This article looks at LOHC candidates that can be obtained from biomass. The special case of formic acid and methanol, which do not fall within the definition of LOHC, is also considered. The synthesis of alcohols, polyols, amines, aminoalcohols and N-heterocyclic compounds from biosourced compounds is reviewed.

In the title molecule, C21H17N3O2, the five-membered ring is slightly ruffled and dihedral angles between the pendant six-membered rings and the central, fivemembered ring vary between 50.78 (4) and 86.78 (10)°. The exocyclic nitrogen lone pair is involved in conjugated π bonding to the five-membered ring. In the crystal, a layered structure is generated by O--H...N and N--H...O hydrogen bonds plus C--H...π(ring) and weak π-stacking interactions. [ABSTRACT FROM AUTHOR]

C-scorpionate metal complexes, specifically, [NiCl2(tpm)]·3H2O, [CoCl2(tpm)]·3H2O and [PdCl2(tpm)] [tpm = hydrotris(1H-pyrazol-1-yl)methane], were effective in the N-formylation and N-methylation of amines using carbon dioxide, as carbon source, in the presence of sodium borohydride. Various parameters were studied, including reaction time, temperature, solvent volume, presence of additives, and catalyst amount. These parameters were found to have a significant impact on the selectivity of the product. [NiCl2(tpm)]·3H2O exhibited good conversion at 80 °C, but its selectivity towards formamide decreased with prolonged reaction time. Increasing the amount of [NiCl2(tpm)]·3H2O, the selectivity changed. [PdCl2(tpm)] showed different selectivity compared to [NiCl2(tpm)]·3H2O, while [CoCl2(tpm)]·3H2O presented poor results. Monitoring the reaction course by 1H NMR revealed the presence of an intermediate species that influenced product formation. These results highlight the versatility and catalytic potential of C-scorpionate metal complexes in the N-formylation/N-methylation of amines in the catalytic system (NaBH4/MeCN/CO2). [ABSTRACT FROM AUTHOR]

Epoxy resins find extensive utility across diverse applications owing to their exceptional adhesion capabilities and robust mechanical and thermal characteristics. However, the demanding reaction conditions, including extended reaction times and elevated reaction temperature requirements, pose significant challenges when using epoxy resins, particularly in advanced applications seeking superior material properties. To surmount these limitations, the conventional approach involves incorporating organic catalysts. Within the ambit of this investigation, we explored the catalytic potential of metallic powders, specifically bismuth (Bi) and silver (Ag), in epoxy resins laden with various curing agents, such as diacids, anhydrides, and amines. Metallic powders exhibited efficacious catalytic activity in epoxy–diacid and epoxy–anhydride systems. In contrast, their influence on epoxy–amine systems was rendered negligible, attributed to the absence of requisite carboxylate functional groups. Additionally, the catalytic performance of Bi and Ag are different, with Bi displaying superior efficiency owing to the presence of inherent metal oxide layers on its powder surfaces. Remarkably, the thermal and mechanical properties of uncatalyzed, fully cured epoxy resins closely paralleled those of their catalyzed counterparts. These findings accentuate the potential of Bi and Ag metal catalysts, particularly in epoxy–diacid and epoxy–anhydride systems, spanning a spectrum of epoxy-based applications. In summary, this investigation elucidates the catalytic capabilities of Bi and Ag metal powders, underscoring their ability to enhance the curing rate of epoxy resin systems involving diacids and anhydrides but not amines. This research points toward a promising trajectory for multifarious epoxy-related applications. [ABSTRACT FROM AUTHOR]

Water-wash section(s) effectively reduce amine compound emissions in amine-based carbon capture processes. Reliable predictions of the behavior of these emission control technologies depend on detailed understanding of the vapor-liquid equilibrium (VLE) of water wash system. However, existing vapor-liquid equilibrium data in the literature focus primarily on solvent-like amine concentrations in amine–CO2–H2O systems; hence, new low-concentration VLE data are needed. In this work, the CO2 solubility in low-concentration solutions of monoethanolamine (MEA), piperazine (PZ), 2-amino-2-methyl-1-propanol (AMP), and AMP/PZ blend (CESAR-1) was investigated for temperatures between 303 and 353 K at atmospheric pressure. Additionally, amine volatility measurements for CO2-loaded low-concentration solutions of MEA, PZ, AMP and CESAR-1 were performed in the range of 313–373 K and 8–96 kPa. Overall, the data show that the CO2 partial pressure increases with increasing CO2 loading and temperature. Similarly, the amine partial pressure increases with increasing pressure and temperature. The new experimental data were compared with two existing VLE models using electrolyte non-random two-liquid activity coefficient models to evaluate the ability of the latter to predict vapor-liquid equilibrium behavior. Both CO2 solubility and amine volatility predictions by the models tend to show significant deviations. The comparison highlight the need for such low-concentration data for all systems studied. This data shall serve to improve existing water-wash modeling tools.

Coupled electrochemical systems for the direct capture and conversion of CO2 have garnered significant attention owing to their potential to enhance energy- and cost-efficiency by circumventing the amine regeneration step. However, optimizing the coupled system is more challenging than handling separated systems because of its complexity, caused by the incorporation of solvent and heterogeneous catalysts. Nevertheless, the deployment of machine learning can be immensely beneficial, reducing both time and cost owing to its ability to simulate and describe complex systems with numerous parameters involved. In this review, we summarized the machine learning techniques employed in the development of CO2 capture solvents such as amine and ionic liquids, as well as electrochemical CO2 conversion catalysts. To optimize a coupled electrochemical system, these two separately developed systems will need to be combined via machine learning techniques in the future.

Background: Particularly developed ingredients that are easily manufactured and utilized for additional exploitation are used in organic synthetic chemistry. Thionyl chloride serves as a significant illustration of such an ingredient. The usefulness of which has been discussed in a huge number of peer-reviewed papers. Aim: The literature that has been released since the previous assessment in 1980, which mainly focused on the responses of active methylene compounds, is where this review places its focus. In the present overview, we also discuss O- and N-nucleophiles. For the most part, patents have been disregarded in this analysis in order to keep it feasible. Conclusion: The authors concluded that SOCl2 has a variety of behaviors, including the ability to function as an initiator or a reactant, which makes it essential for the synthesis of many chemically reactive intermediates and final products. Additionally, SOCl2 can speed up and reduce the duration of traditionally long reactions, thereby raising its importance.

The present study aimed to investigate the effect of catalase (CAT) on the growth performance, antioxidation, and microbial metabolism of weaned rabbits. Dietary treatments consisted of control and CAT supplementation at 100 (T1), 150 (T2), and 200 IU/kg of diet (T3). A total of 240 weaned rabbits were randomly assigned to 4 groups with 6 replicates of 10 rabbits each. The feeding trial lasted for 28 days. Results showed that T2 and T3 increased (P < 0.05) body weight gain and gain/feed ratio, and decreased (P < 0.05) diarrhoea rate, compared to the control. Also, serum antioxidative parameters and oxidative stress products were beneficially regulated (P < 0.05) by the dietary CAT administration. Faecal microbiota including Bacteroidetes, Prevotella, and Bifidobacterium in T2 or T3 was increased (P < 0.05). Dietary CAT with changed microbiota further influenced the metabolites from carbohydrates and proteins, evidenced by increased lactic acid, acetate, branched-chain fatty acids, and short-chain fatty acids, and decreased valerate, isovalerate, methylamine, tryptamine, putrescine, cadaverine, spermidine, and total amines. It is concluded that CAT can be used to improve growth performance by beneficially regulating the antioxidation, microbiota, and metabolites in weaned rabbits.

Rechargeable aluminium (Al) batteries (RABs) have long-been pursued due to the high sustainability and three-electron-transfer properties of Al metal. However, limited redox chemistry is available for rechargeable Al batteries, which restricts the exploration of cathode materials. Herein, we demonstrate an efficient Al-amine battery based on a quaternization reaction, in which nitrogen (radical) cations (R3 N.+ or R4 N+ ) are formed to store the anionic Al complex. The reactive aromatic amine molecules further oligomerize during cycling, inhibiting amine dissolution into the electrolyte. Consequently, the constructed Al-amine battery exhibits a high reversible capacity of 135 mAh g-1 along with a superior cycling life (4000 cycles), fast charge capability and a high energy efficiency of 94.2 %. Moreover, the Al-amine battery shows excellent stability against self-discharge, far beyond conventional Al-graphite batteries. Our findings pave an avenue to advance the chemistry of RABs and thus battery performance.

Mass transfer performance of CO2 absorption is based on selecting an effective amine solvent, hence, an examination of the overall mass transfer coefficient (KGav) and CO2 removal efficiency, is significant for obtaining the most favorable CO2 capture performance. This study compared KGavand CO2 removal efficiency of the highly concentrated ternary amines solvent at various concentrations with the benchmark monoethanolamine (MEA) in a laboratory scale CO2 absorption packed-column. The six blends of 2-amino-2-methyl-1-propanol (AMP), piperazine (PZ), and MEA are formulated as ternary solvents at high PZ/AMP molar ratio (1.25–3.75) and total amine concentration (6M and 7M). Be noted that the solvent precipitation was not observed in this study. The absorption experiment was operated at 303 K temperature, 12% CO2 by volume, and CO2 loading of 0.25 mol CO2/mol amine. The experimental results showed that KGavand CO2 removal efficiency for AMP-PZ-MEA and MEA solvents increased as total amine concentration increased. Also, KGavand CO2 removal efficiency of the PZ-AMP-MEA solvent are greater than those of 5M MEA. An increase of PZ/AMP molar ratio had a positive influence on the absorption performance for ternary amines. In comparison with the benchmark 5M MEA, all the studied AMP-PZ-MEA solvents showed an outperformance. The two suggested formulae, which are 0.95:3.55:1.5 (6M) and 0.95:3.55:2.5 (7M), possessed approximately 1.5 and 2.5 times higher KGavand 17.34% and 17.63% greater CO2 removal efficiency compared with the benchmark 5M MEA.

The title compound, systematic name 4,4′,6,6′-tetrachloro-2,2′-{[(2-methoxyethyl)azanediyl]bis(methylene)}diphenol (C17H17Cl4NO, 1), was prepared via a modified Mannich reaction between 2-methoxyethylamine, 2,4-dichlorophenol, and aqueous formaldehyde. The resulting amine bis(phenol) provides an interesting comparison to related species as a result of the electron-withdrawing substituents on the phenol rings, in combination with similar steric parameters. One of the Cl atoms was modeled as a two-component disorder with partial occupancies of 0.49 (3) and 0.51 (3), while the pendant ether group was modeled as a two-component disorder with partial occupancies of 0.867 (3) and 0.133 (3). A comparison of metrical parameters for the title compound and closely related structures provides insight into the use of these species as ligands to support transition-metal complexes for applications as homogeneous catalysts.

Ammonium and polyamines are essential nitrogen metabolites in all living organisms. Crosstalk between ammonium and polyamines through their metabolic pathways has been demonstrated in plants and animals, while no research has been directed to explore this relationship in algae or to investigate the underlying molecular mechanisms. Previous research demonstrated that high concentrations of ammonium and putrescine were among the active substances in bacteria-derived algicide targeting dinoflagellates, suggesting that the biochemical inter-connection and/or interaction of these nitrogen compounds play an essential role in controlling these ecologically important algal species. In this research, putrescine, ammonium, or a combination of putrescine and ammonium was added to cultures of three dinoflagellate species to explore their effects. The results demonstrated the dose-dependent and species-specific synergistic effects of putrescine and ammonium on these species. To further explore the molecular mechanisms behind the synergistic effects, transcriptome analysis was conducted on dinoflagellate Karlodinium veneficum treated with putrescine or ammonium vs. a combination of putrescine and ammonium. The results suggested that the synergistic effects of putrescine and ammonium disrupted polyamine homeostasis and reduced ammonium tolerance, which may have contributed to the cell death of K. veneficum. There was also transcriptomic evidence of damage to chloroplasts and impaired photosynthesis of K. veneficum. This research illustrates the molecular mechanisms underlying the synergistic effects of the major nitrogen metabolites, ammonium and putrescine, in dinoflagellates and provides direction for future studies on polyamine biology in algal species. [ABSTRACT FROM AUTHOR]

Recent research on atmospheric particle formation has shown substantial discrepancies between observed and modeled atmospheric sulfate levels. This is because models mostly consider sulfate originating from S O 2 oxidation by •OH radicals in mechanisms catalyzed by solar radiation while ignoring other pathways of non-radical S O 2 oxidation that would substantially alter atmospheric sulfate levels. Herein, we use high-level quantum chemical calculations based on density functional theory and coupled cluster theory to show that monoethanolamine (MEA), a typical alkanolamine pollutant released from C O 2 capture technology, can facilitate the conversion of atmospheric S O 2 to sulfate in a non – •OH – radical oxidation mechanism. The initial process is the MEA-induced S O 2 hydrolysis leading to the formation of H O S O 2 − • M E A H + . The latter entity is thereafter oxidized by ozone ( O 3 ) and nitrogen dioxide ( N O 2 ) to form H S O 4 − • M E A H + , which is an identified stabilizing entity in sulfate-based aerosol formation. Results show that the H O S O 2 − • M E A H + reaction with O 3 is kinetically and thermodynamically more feasible than the reaction with N O 2 . The presence of an additional water molecule further promotes the H O S O 2 − • M E A H + reaction with O 3 , which occurs in a barrierless process, while it instead favors HONO formation in the reaction with N O 2 . The investigated pathway highlights the potential role alkanolamines may play in S O 2 oxidation to sulfate, especially under conditions that are not favorable for •OH production, thereby providing an alternative sulfate source for aerosol modeling. The studied mechanism is not only relevant to sulfate formation and may effectively compete with reactions with sulfur dioxide and hydroxyl radicals under heavily polluted and highly humid conditions such as haze events, but also an important pathway in MEA removal processes. [ABSTRACT FROM AUTHOR]

Functional ionic liquids have been widely used in the fields of synthetic chemistry, analytical chemistry, electrochemistry and material chemistry owing to their excellent properties such as easy structure modification and adjustable properties. In this work, a series of basic functionalized ionic liquids were prepared from 1, 4-diazabicyclo [2.2.2] octane (DABCO) or hexamethylenetetramine (HMTA) with various halogenated hydrocarbons, then these functional ionic liquids and water were used as solvent-catalyst system in the Knoevenagel reaction of various aldehydes with ethyl cyanoacetate or malononitrile, the influence of the structure of the ionic liquid and the content of water was investigated. The results showed that the composite solvent-catalyst system mixed by the functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo [2.2.2] octane bromide with water can effectively promote the Knoevenagel reaction and the alkalinity of amine and hydrogen bond play an important role. Aromatic aldehydes with electron-donating or electron-withdrawing groups can obtain the target product at an excellent yield (79-99%). It is worth noting that the polycyclic aromatic aldehydes with high steric hindrance, 86%-95% yields of the object products were also obtained after 15 h-25 h. Furthermore, the catalyst could be reused for 6 times without any loss in its catalytic activity. The composite solvent-catalyst system mixed by the Functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo[2.2.2]octane bromide with water can effectively promote the Knoevenagel reaction, even for the electron-rich aromatic aldehydes with poor reactivity, high yields of the target products and fast reaction rate were also obtained at room temperature. [ABSTRACT FROM AUTHOR]

Nanosheets of layered perovskite-like oxides attract researchers as building blocks for the creation of a wide range of demanded nanomaterials. However, Ruddlesden–Popper phases are difficult to separate into nanosheets quantitatively via the conventional liquid-phase exfoliation procedure in aqueous solutions of bulky organic bases. The present study has considered systematically a relatively novel and efficient approach to a high-yield preparation of concentrated suspensions of perovskite nanosheets. For this, the Ruddlesden–Popper titanates HLnTiO4 and H2Ln2Ti3O10 (Ln = La, Nd) have been intercalated by n-alkylamines with various chain lengths, exposed to sonication in aqueous tetrabutylammonium hydroxide (TBAOH) and centrifuged to separate the nanosheet-containing supernatant. The experiments included variations of a wide range of conditions, which allowed for the achievement of impressive nanosheet concentrations in suspensions up to 2.1 g/L and yields up to 95%. The latter were found to strongly depend on the length of intercalated n-alkylamines. Despite the less expanded interlayer space, the titanates modified with short-chain amines demonstrated a much higher completeness of liquid-phase exfoliation as compared to those with long-chain ones. It was also shown that the exfoliation efficiency depends more on the sample stirring time in the TBAOH solution than on the sonication duration. Analysis of the titanate nanosheets obtained by means of dynamic light scattering, electron and atomic force microscopy revealed their lateral sizes of 30–250 nm and thickness of 2–4 nm. The investigated exfoliation strategy appears to be convenient for the high-yield production of perovskite nanosheet-based materials for photocatalytic hydrogen production, environmental remediation and other applications. [ABSTRACT FROM AUTHOR]

Catalytic transfer hydrogenation has emerged as a pivotal chemical process with transformative potential in various industries. This review highlights the significance of catalytic transfer hydrogenation, a reaction that facilitates the transfer of hydrogen from one molecule to another, using a distinct molecule as the hydrogen source in the presence of a catalyst. Unlike conventional direct hydrogenation, catalytic transfer hydrogenation offers numerous advantages, such as enhanced safety, cost-effective hydrogen donors, byproduct recyclability, catalyst accessibility, and the potential for catalytic asymmetric transfer hydrogenation, particularly with chiral ligands. Moreover, the diverse range of hydrogen donor molecules utilized in this reaction have been explored, shedding light on their unique properties and their impact on catalytic systems and the mechanism elucidation of some reactions. Alcohols such as methanol and isopropanol are prominent hydrogen donors, demonstrating remarkable efficacy in various reductions. Formic acid offers irreversible hydrogenation, preventing the occurrence of reverse reactions, and is extensively utilized in chiral compound synthesis. Unconventional donors such as 1,4-cyclohexadiene and glycerol have shown a good efficiency in reducing unsaturated compounds, with glycerol additionally serving as a green solvent in some transformations. The compatibility of these donors with various catalysts, substrates, and reaction conditions were all discussed. Furthermore, this paper outlines future trends which include the utilization of biomass-derived hydrogen donors, the exploration of hydrogen storage materials such as metal-organic frameworks (MOFs), catalyst development for enhanced activity and recyclability, and the utilization of eco-friendly solvents such as glycerol and ionic liquids. Innovative heating methods, diverse base materials, and continued research into catalyst-hydrogen donor interactions are aimed to shape the future of catalytic transfer hydrogenation, enhancing its selectivity and efficiency across various industries and applications. [ABSTRACT FROM AUTHOR]

A C-N cross-coupling approach involving oxidative amidations of aromatic aldehydes in the presence of an amide-based nickel(II) pincer catalyst (2) is demonstrated. Upon optimization, quick reaction times (15 min) and an ideal temperature (25 °C) were established and implemented for the conversion of 33 different amide products using only 0.2 mol% of catalyst. Moderate to good turnover numbers (TONs) were obtained for secondary benzamide products, and moderate TONs were obtained for tertiary benzamide products, with the highest turnover number calculated for the 4-chloro-N-(3-phenylpropyl)benzamide product (4i, 309). Gas chromatographic–mass spectrometric (GC–MS) analysis also indicates the formation of alcohols in different reactions, indicating an oxidative amidation process. Kinetic studies were performed by varying the amount of catalyst, aldehyde, LiHMDS base, and amine substrate to determine the order of reaction for each component. Benzaldehyde and benzaldehyde-d6 were reacted with benzylamine, and the kH/kD ratio was determined to understand the rate-determining step. Isotope labeling further revealed that deuterium was being transferred to both the alcohol side product and the target amide product. With the help of kinetic data and UV–visible spectra, a mechanism for the amidation process via the catalyst (2) is proposed through a Ni(I)–Ni(III) pathway. [ABSTRACT FROM AUTHOR]

Aim. To synthesize cyclobutane-derived amines and carboxylic acids bearing CH2F or CHF2 groups in the α position; to determine the regularities of the effect of fluoroalkyl substituents on the acid-base properties of the title compounds. Results and discussion. Synthetic approaches to 1-(fluoromethyl)- and 1-(difluoromethyl)cyclobutanamines, 1-(fluoromethyl)- and 1-(difluoromethyl)cyclobutanecarboxylic acids have been developed. It has been found that the pKa (pKa(H)) values measured for the title compounds, as well as for their non-substituted and CF3-substituted analogues, are consistent with the electron-withdrawing effect of the corresponding fluoroalkyl substituents. Experimental part. The synthesis of the title compounds commenced from the known ethyl 1-(hydroxymethyl)cyclobutanecarboxylate or the product of its Swern oxidation (the corresponding aldehyde) and included fluorination, alkaline ester hydrolysis (for carboxylic acids), and modified Curtius rearrangement (for amines). The pKa value was determined from the pre-equivalence point part of the titration curve using the standard acid-base titration. Conclusions. A newly developed synthetic approach to 1-(fluoromethyl)- and 1-(difluoromethyl)cyclobutanamines, 1-(fluoromethyl)- and 1-(difluoromethyl)cyclobutanecarboxylic acids allows to obtain the title compounds in multigram quantities (up to 97 g). With a single exception, the acid-base properties of these products, as well as their parent non-substituted and CF3-substituted analogues, change in a monotonous manner in accordance with inductive electronic effect of the fluorine atom(s).

The title complex, [PdCl2(C9H13N)2], comprises a single molecule in the asymmetric unit. The PdII atom is tetracoordinated by two N atoms from two trans-aligned organic ligands and two Cl ligands, forming a square-planar metal coordination environment. The distances from the ortho-H atoms on the phenyl ring to the central PdII atom fall within the range 4.70–5.30 Å, precluding any significant intramolecular Pd...H interactions.

Novel compounds derived from hydantoin were synthesized using a chloroacetyl chloride linker in conjunction with terminal compounds of sulphonamides and amines. The compounds were subjected to various analytical techniques, including LC-MS/MS, 1H NMR, 13C NMR, FT-IR, and determination of melting point. Subsequently, the synthesized compounds were evaluated for their potential anti-cancer properties (against) breast cancer (MCF-7) and lung cancer (A549) cell lines by the MTT assay. Additionally, the compounds' anticonvulsant activity was assessed using pentylenetetrazol (PTZ)-induced seizure in mice. Furthermore, the inhibitory activity of selected compounds against the PI3Kα enzyme at a concentration of 100 µM was investigated. The biological evaluation of the compounds did not show the expected anticonvulsant effect when tested at various doses (5, 10, and 20 mg/kg b.w using the intraperitoneal injection), with all mice showing a seizure score of 5. MTT assay showed moderate anti-cancer activity against, the (A549) cell line, with compound 37 exhibiting the highest inhibition of cell viability at 55.1%. In the case of the breast cancer cell line, compounds 37, 40, 42, and 45 demonstrated inhibition percentages ranging from 64% to 74%. Moreover, the compounds displayed a relatively limited inhibitory effect on PI3Kα activity during the in-vitro evaluation compared to staurosporine. These findings suggest that further optimization and modification of the synthesized compounds may be necessary to enhance their anticonvulsant and anti-cancer properties, particularly regarding PI3Kα inhibition.

A new method for making use of the catalytic ending PdII-H for the relay-catalytic cycle for dicarbonylation of amines has been developed in a buffer condition, which shows an excellent compatible ability to allow two incompatible catalytic systems working simultaneously in the same catalytic system. [Display omitted] • A novel method for making use of the catalytic ending PdII-H into the next relay-catalytic cycle for dicarbonylation of amines in a buffer condition has been developed. • Two incompatible catalytic systems to work simultaneously in the same catalytic system. • This protocol features excellent regioselectivity and broad substrate scope. A new method for making use of the catalytic ending PdII-H for the relay-catalytic cycle for dicarbonylation of amines has been developed in a buffer condition, which shows an excellent compatible ability to allow two incompatible catalytic systems working simultaneously in the same catalytic system. This protocol features excellent regioselectivity and broad substrate scope. Our combined experimental and computational studies indicated that the reaction proceeds through a Pd0/PdII-H relay-catalytic cycle. [ABSTRACT FROM AUTHOR]

This work describes the spray pyrolysis deposition of PbSe films, using as-prepared PbSe colloids as the starting solution. The PbSe colloids were prepared by using the alkahest approach, where Pb and Se precursors were made to react with the following green polyols: glycerin, ethylene glycol, and propylene glycol, to subsequently spray them onto glass substrates. The results of the characterization indicated that amine or thiol groups-free and single-phase rock-salt cubic PbSe powder was obtained, producing nanocrystals 16–30 nm in size. X-ray diffraction also showed that the PbSe films containing PbSeO3 and PbO·xH2O as impurity phases were produced during the deposition. The morphology of the powders and films was developed by a self-assembly process, in which the primary PbSe nanoparticles self-assemble to produce peanut-like microstructures. Additionally, a non-continuous and porous feature was formed in the thick films. Certain films revealed optical structures characterized by broad- and low-intensity bands resembling an exciton-like behavior. This could be attributed to the presence of nanocrystals with a size less than the Bohr radius, indicating reminiscent quantum effects. The results suggest that the usage of colloidal dispersions as spray solutions represents an effective approach to forming PbSe films, as well as that the synthesis method allows for the elimination of thiol and amine groups before deposition, significantly simplifying the process. [ABSTRACT FROM AUTHOR]