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All-inorganic CsPbI2Br inverted perovskite solar cells (PSCs) have drawn increasing attention because of their outstanding thermal stability and compatible process with tandem cells. However, relatively low open circuit voltage (Voc) has lagged their progress far behind theoretical limits. Herein, we introduce phenylmethylammonium iodide and 4-trifluoromethyl phenylmethylammonium iodide (CFPMAI) on the surface of a CsPbI2Br perovskite film and investigate their passivation effects. It is found that CFPMAI with a –CF3 substituent significantly decreases the trap density of the perovskite film by forming interactions with the under-coordinated Pb2+ ions and effectively suppresses the non-radiative recombination in the resulting PSC. In addition, CFPMAI surface passivation facilitates the optimization of energy-level alignment at the CsPbI2Br perovskite/[6,6]-phenyl C61 butyric acid methyl ester interface, resulting in improved charge extraction from the perovskite to the charge transport layer. Consequently, the optimized inverted CsPbI2Br device exhibits a markedly improved champion efficiency of 14.43% with a Voc of 1.12 V, a Jsc of 16.31 mA/cm2, and a fill factor of 79.02%, compared to the 10.92% (Voc of 0.95 V) efficiency of the control device. This study confirms the importance of substituent groups on surface passivation molecules for effective passivation of defects and optimization of energy levels, particularly for Voc improvement. [ABSTRACT FROM AUTHOR]

A comparative study of experimentally established structures, stability and energetic performance of ammonium and hydrazinium salts of 4H-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazole (triazolofurazan, TF) as well as its N-oxide and N-nitroimide was performed. The aim of this study was to reveal the structure–property relationships of heterocyclic systems by the example of triazolofurazan derivatives. It was shown that the introduction of N-oxide oxygen into position 5 of the TF anion led to a small loss in enthalpy of formation (4 kcal mol−1) while the introduction of the N–NO2 (N-nitroimido) group in the same position added a significant amount of energy into the molecule (36 kcal mol−1). Both substituents improved the oxygen balance and increased the density (0.065–0.22 g cm−3) of the final salts; however, only N-oxide enhanced the thermal stability by ca. 35–45 °C, while N-nitroimide either remained unchanged or decreased the heat resistance compared to unsubstituted analogues. [ABSTRACT FROM AUTHOR]

Aliphatic quaternary ammonium salts (QASs) with intrinsic photoluminescence (PL) have drawn increasing attention due to the importance of exploring the mechanism of ionic emissive clusters, whereas it remains challenging to clarify structure–property relationships. Here, the effective modulation of photophysical properties of gemini aliphatic QASs (n‐BTADB) is managed by altering the alkyl chain length. Boosted quantum yields (up to 24.6%), prolonged phosphorescence lifetimes (up to 515.2 ms), and varied PL colors are achieved by manipulating the aggregation states of the compounds. Interlaced herringbone packing patterns and strong ionic interactions facilitate the intersystem crossing process and stabilize the triplets. The confluence of varied hydrophobic interactions and chain flexibility results in the fluctuation of phosphorescence lifetimes as the alkyl chain lengthens. Furthermore, the single‐component white‐light emission is obtained in 12‐HBTADB crystals by introducing electron‐rich hydroxyls. These results shed new light on the structure–property relationships of ionic emissive clusters and the rational design of nonconventional ionic luminophores. [ABSTRACT FROM AUTHOR]

Key to the success of the ground bait spray application method ('attract and kill') against Bactrocera oleae is to effectively suppress its population by inducing good levels of attraction and stimulate flies to ingest a lethal dose of the toxicant. A 2-year long field bioassay (fly captures to sticky panels) was developed to evaluate the exposure and response of olive flies to hydrolyzed protein based and ammonium salt baits in combination with various insecticides. A significantly higher attractive response of fruit flies was recorded in the case of the protein Entomella/phosmet combinations among protein bait/combination. Though next year, an enhanced attractive effect and a longer residual activity of ammonium salts compared to the tested protein to the olive fruit fly was clearly demonstrated. Especially in the case of beta-cyfluthrin mixed with ammonium salts, the mean number of captured flies were at least 3 to 11-fold (depending on the salt) higher compared to the respective protein-containing mixture baits instead of the organophosphate phosmet. Ammonium salts can successfully replace proteins in bait sprays. [ABSTRACT FROM AUTHOR]

Aluminum‐air battery (AAB) with alkaline‐based aqueous electrolyte have attracted intensive research interests due to high‐capacity density, low cost, and high safety. However, severe hydrogen evolution reaction (HER) of Al anode in alkaline electrolyte extremely restricts its large‐scale application. In this work, ZnO with a group of quaternary ammonium salts (QAS, denoted as C1, C2, C4, C6, and C8 depending on the length of non‐polar group) are introduced into electrolytes to inhibit HER. It is revealing that capacity density initially increases with C1, C2, or C4, up to 2564 mAh gAl−1 with anodic utilization rate of 86.0%, and then follows by a decline (C6 and C8). The addition of QAS creates "physical‐hydrophobic interface" by non‐polar group owing to its electrophilic property and constructs "chemical‐hydrophobic interface" with polar group by reducing water activity. QAS also promotes the uniform growth of Zn‐based film, as a barrier against H2O. Thus, HER is effectively inhibited to improve the capacity density. With further increasing non‐polar group length (C6 or C8), the bonding status of the film deteriorates with enhanced H2O activity, leading to the recurrence of HER. This work explores the effect of non‐polar groups on inhibiting HER and opens the door to stable anodes for alkaline‐based batteries. [ABSTRACT FROM AUTHOR]

Newly synthesized gemini quaternary ammonium salts (QAS) with different counterions (bromide, hydrogen chloride, methylcarbonate, acetate, lactate), chain lengths (C12, C14, C16) and methylene linker (3xCH2) were tested. Dihydrochlorides and dibromides with 12 carbon atoms in hydrophobic chains were characterized by the highest biological activity against planktonic forms of yeast and yeast-like fungi. The tested gemini surfactants also inhibited the production of filaments by C. albicans. Moreover, they reduced the adhesion of C. albicans cells to the surfaces of stainless steel, silicone and glass, and slightly to polystyrene. In particular, the gemini compounds with 16-carbon alkyl chains were most effective against biofilms. It was also found that the tested surfactants were not cytotoxic to yeast cells. Moreover, dimethylcarbonate (2xC12MeCO3G3) did not cause hemolysis of sheep erythrocytes. Dihydrochlorides, dilactate and diacetate showed no mutagenic potential. [ABSTRACT FROM AUTHOR]

Amidation of lactobionic acid with N,N-dimethylaminopropyltriamine was conducted to obtain N-(3′-dimethylaminopropyl)-lactamido-3-aminopropane (DDLPD), which was quaternized with bromoalkanes of different carbon chain lengths to synthesize double-stranded lactosylamide quaternary ammonium salt N-[N′[3-(lactosylamide)]propyl-N′-alkyl] propyl-N,N-dimethyl-N-alkylammonium bromide (CnDDLPB, n = 8, 10, 12, 14, 16). The surface activity and the adsorption and aggregation behaviors of the surfactants were investigated via equilibrium surface tension, dynamic light scattering, and cryo-electron microscopy measurements in an aqueous solution. The application properties of the products in terms of wettability, emulsification, foam properties, antistatic, salt resistance, and bacteriostatic properties were tested. CnDDLPB exhibited a low equilibrium surface tension of 27.82 mN/m. With an increase in the carbon chain length, the critical micellar concentration of CnDDLPBD decreased. Cryo-electron microscopy revealed that all products except C8DDLPB formed stable monolayer, multi-layer, and multi-compartmental vesicle structures in an aqueous solution. C14DDLPB has the best emulsification performance on soybean oil, with a time of 16.6 min; C14DDLPB has good wetting and spreading properties on polytetrafluoroethylene (PTFE) when the length of carbon chain is from 8 to 14, and the contact angle can be lowered to 33°~40°; CnDDLPB has low foam, which is typical of low-foaming products; C8DDLPB and C10DDLPB both show good antistatic properties. C8DDLPB and C14DDLPB have good salt resistance, and C12DDLPB has the best antimicrobial property, with the inhibition rate of 99.29% and 95.28% for E. coli and Gluconococcus aureus, respectively, at a concentration of 350 ppm. [ABSTRACT FROM AUTHOR]

Gemini-type imidazoline quaternary ammonium salt is a new type of environmentally friendly corrosion inhibitor has been widely used in engineering materials. However, most of them are hazardous/toxic compounds derived from petroleum-based products, which did harm to environment. In this work, an environmentally friendly Gemini-shaped imidazoline quaternary ammonium salt corrosion inhibitor (G211) was synthesized using cheap fatty acid recycled from dimer acid industry as feedstock. The corrosion inhibition effects of G211 on Q235 steel in 1 M HCl solution were investigated through weight loss experiments, potential polarization curves, and alternating current impedance spectroscopy experiments. The results show that the inhibition rate of G211 as a mixed-type inhibitor is up to 94.4% and the concentration drop as low as 500 ppm at 25 ℃. The adsorption of G211 on Q235 surface follows Langmuir adsorption isothermal curve. The chemical composition of the Q235 steel surface was analyzed through scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Furthermore, the possible corrosion inhibition mechanism of G211 on the surface of Q235 steel is proposed. This article not only presents an outstanding solution for safeguarding Q235 steel against corrosion but also introduces a feasible method for high-value utilization of monomer acid (MA). [ABSTRACT FROM AUTHOR]

C−H metalation is the most efficient method to prepare aryl–zinc and –aluminium complexes that are ubiquitous nucleophiles. Virtually all C−H metalation routes to form Al/Zn organometallics require stoichiometric, strong Brønsted bases with no base‐catalyzed reactions reported. Herein we present a catalytic in amine/ammonium salt (Et3N/[(Et3N)H]+) C−H metalation process to form aryl‐zinc and aryl‐aluminium complexes. Key to this approach is coupling an endergonic C−H metalation step with a sufficiently exergonic dehydrocoupling step between the ammonium salt by‐product of C−H metalation ([(Et3N)H]+) and a Zn−H or Al−Me containing complex. This step, forming H2/MeH, makes the overall cycle exergonic while generating more of the reactive metal electrophile. Mechanistic studies supported by DFT calculations revealed metal‐specific dehydrocoupling pathways, with the divergent reactivity due to the different metal valency (which impacts the accessibility of amine‐free cationic metal complexes) and steric environment. Notably, dehydrocoupling in the zinc system proceeds through a ligand‐mediated pathway involving protonation of the β‐diketiminate Cγ position. Given this process is applicable to two disparate metals (Zn and Al), other main group metals and ligand sets are expected to be amenable to this transition metal‐free, catalytic C−H metalation. [ABSTRACT FROM AUTHOR]

Alkylation reactions are pivotal in organic chemistry, with wide‐ranging utilization across various fields of applied synthetic chemistry. However, conventional reagents employed in alkylations often pose substantial health and exposure risks. Quaternary ammonium salts (QAS) present a promising alternative for these transformations offering significantly reduced hazards as they are non‐cancerogenic, non‐mutagenic, non‐flammable, and non‐corrosive. Despite their potential, their use in direct organic transformations remains relatively unexplored. This review outlines strategies for utilizing QAS as alternative reagents in alkylation reactions, providing researchers with safer approaches to chemical synthesis. [ABSTRACT FROM AUTHOR]

C−H metalation is the most efficient method to prepare aryl–zinc and –aluminium complexes that are ubiquitous nucleophiles. Virtually all C−H metalation routes to form Al/Zn organometallics require stoichiometric, strong Brønsted bases with no base‐catalyzed reactions reported. Herein we present a catalytic in amine/ammonium salt (Et3N/[(Et3N)H]+) C−H metalation process to form aryl‐zinc and aryl‐aluminium complexes. Key to this approach is coupling an endergonic C−H metalation step with a sufficiently exergonic dehydrocoupling step between the ammonium salt by‐product of C−H metalation ([(Et3N)H]+) and a Zn−H or Al−Me containing complex. This step, forming H2/MeH, makes the overall cycle exergonic while generating more of the reactive metal electrophile. Mechanistic studies supported by DFT calculations revealed metal‐specific dehydrocoupling pathways, with the divergent reactivity due to the different metal valency (which impacts the accessibility of amine‐free cationic metal complexes) and steric environment. Notably, dehydrocoupling in the zinc system proceeds through a ligand‐mediated pathway involving protonation of the β‐diketiminate Cγ position. Given this process is applicable to two disparate metals (Zn and Al), other main group metals and ligand sets are expected to be amenable to this transition metal‐free, catalytic C−H metalation. [ABSTRACT FROM AUTHOR]

The necessary use of large amounts of a homogeneous electrolyte represents a major issue and challenge for the whole sustainability of electrosynthetic procedures. Herein, we report the use of a solid ammonium salt (e.g. Amberlyst-400-Cl, Amb-400-Cl) as a reusable electrolyte with excellent performance in the representative electrosynthesis of 2-arylbenzoxazoles. Amb-400-Cl works efficiently without adding any additional supporting electrolytes or mediators, and it can be reused without the need for a regeneration procedure. Exploiting this finding, a sustainable electro-promoted protocol has been developed under batch and flow conditions, which proves that the reported chemical and technological innovation leads to significant improvements compared to the literature processes. Extensive green metrics analysis has also been reported to fully quantify the advances in terms of sustainability. [ABSTRACT FROM AUTHOR]

Luminescent materials with multiple emission centers are attracting more and more attentions due to their potential applications in multicolor displays, polychromatic imaging, information encryption, and ratiometric chemical sensing. Organic molecules with phosphorescence behavior at room temperature (RTP) provide idea candidate for constructing luminescent materials with multiple emission centers, which show great potentials for application in ratiometric chemical sensing owing to its long‐lived emission and high signal‐to‐noise ratio. However, developing RTP materials with multiple emission centers and their application in aqueous solutions remains a huge challenge. Herein, two chromophore isomers (p‐N‐DPC·(PF6)2 and m‐N‐DPC·(PF6)2) based on carbazole and naphthalene units are prepared by using pyridine quaternary ammonium salt as link to improve their solubility in water and form electron deficient centers to facilitate charge transfer (CT). p‐N‐DPC·(PF6)2 displayed multiple emissions behavior, including monomer fluorescence, dimer fluorescence, monomer phosphorescence, dimer phosphorescence, and CT phosphorescence. Especially, p‐N‐DPC·(PF6)2 exhibits monomer fluorescence, dimer fluorescence, and CT phosphorescence in an aqueous solution, which is successfully applied as self‐calibrated dual ratio luminescent sensor for phosphate detection. This study not only provides a strategy to construct luminophore with multiple emissions but also develops a fluorescence/ phosphorescence dual ratio luminescent sensor in an aqueous solution. [ABSTRACT FROM AUTHOR]

The direct palladium‐catalyzed C−H arylation of 1,3,4‐oxadiazoles with challenging aryl chloride substrates is promoted by the use of a specifically designed electron‐rich ferrocenyl diphosphane. This protocol employs 0.5 to 1.0 mol % catalyst loading without any additives such as copper or ammonium salts, and equally tolerates electron‐donating and electron‐withdrawing substituents on the (heteroaryl)aryl halides, as illustrated by the efficient synthesis in 86 % yield of the anti‐tubercular agent PHOXPY (2‐(5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)pyrazine) by a late‐stage arylation using 2‐chloropyrazine. [ABSTRACT FROM AUTHOR]

Double epoxy group double quaternary ammonium salts (DEpDQAS) were synthesized by epichlorohydrin (ECH) reacting with N,N,N'N'-tetramethylethylenediamine (TMEDA) and N,N,N'N'-tetramethyl-1,6-hexanediamine (TMHDA), respectively. The results of orthogonal experiments showed that temperature and time were the key factors influencing on epoxy value and quaternarization ratio respectively. The optimal condition for higher epoxy value was the reaction temperature at 15 °C and methanol as solvent. The reaction kinetic process was determined by conductivity, which showed that the reaction had a short induction period and appeared discontinuity in progress that the reaction rate of the first stage was almost constant, while the reaction rate of the second stage decreased gradually. The product was characterized by infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). The results of surface tension testing showed that DEpDQAS-6 with longer spacer chain had better surface activity and lowered the solution surface tension to 26 mN·m−1 at 25 °C and CMC 0.27 mol·L−1. The thermodynamic parameters of micellization were obtained basing on charged pseudo-phase model. The studies of cytotoxicity in vitro and antibacterial activity showed that DEpDQAS was biocompatible and its antibacterial activity was more effective against Escherichia coli than against Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Under-deposit corrosion is widely present in the pipelines of oil and gas production, causing significant corrosion damage. In this paper, a novel electrochemical cathodic-polarization method was carried out to accelerate the formation of CaCO3 scale on a X65 steel surface in a simulated solution containing scaling ions. Subsequently, pre-scaled X65 steel was placed in a high temperature and pressure autoclave to conduct corrosion weight-loss experiments and in situ electrochemical measurements. The study mainly compared the corrosion inhibition behavior of four quaternary ammonium salt corrosion inhibitors, pyridinium quaternary salt (BPC), quinolinium quaternary salt (BQC), 8-hydroxyquinolinium quaternary salt (BHQ) and pyridinium (1-chloromethyl naphthalene) quaternary salt (1-CPN), in a simulated oilfield scale under corrosive conditions. The results of the weight-loss experiments demonstrated that the inhibition efficiencies of the corrosion inhibitors from high to low were as follows: 1-CPN < BHQ < BQC < BPC. The in situ electrochemical measurements showed that the immersion time and type of corrosion inhibitor had a pronounced influence on the corrosion and corrosion inhibition behavior of X65 steel with CaCO3 coating. It was also proved using both EIS and PC that 1-CPN shows the best inhibition performance in all. Lastly, the inhibition mechanism of corrosion inhibitors at under-deposit conditions was analyzed via a surface morphology observation of SEM. [ABSTRACT FROM AUTHOR]

The fibers from four wheat varieties (FT, XW 26, XW 45, and KW 1701) were selected and chemically modified with NaOH, epichlorohydrin, and dimethylamine to improve the adsorption capacity for anionic dye. The structure of the fibers with or without modification was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectrometry. The modified products were studied from the aspects of adsorption capacities, adsorption kinetics, and thermodynamics to provide a reference for the utilization of wheat bran. By SEM, more porous and irregular structures were found on the modified fibers. The XRD results showed that the crystals from the original fibers were destroyed in the modification process. The changes in fibers' infrared spectra before and after modification suggested that quaternary ammonium salts were probably formed in the modification process. The maximum adsorption capacity of wheat bran fibers for Congo red within 120 min was 20 mg/g for the unmodified fiber (XW 26) and 93.46 mg/g for the modified one (XW 45). The adsorption kinetics of Congo red by modified wheat bran fiber was in accord with the pseudo-second-order kinetic model at 40 °C, 50 °C, and 60 °C, indicating that the adsorption process might be mainly dominated by chemisorption. The adsorption was more consistent with the Langmuir isothermal adsorption model, implying that this process was monolayer adsorption. The thermodynamic parameters suggested that the adsorption occurred spontaneously, and the temperature increase was favorable to the adsorption. As mentioned above, this study proved that the wheat bran fiber could possess good adsorption capacities for anion dye after chemical modification. [ABSTRACT FROM AUTHOR]

Esterquats constitute a unique group of quaternary ammonium salts (QASs) that contain an ester bond in the structure of the cation. Despite the numerous advantages of this class of compounds, only two mini-reviews discuss the subject of esterquats: the first one (2007) briefly summarizes their types, synthesis, and structural elements required for a beneficial environmental profile and only briefly covers their applications whereas the second one only reviews the stability of selected betaine-type esterquats in aqueous solutions. The rationale for writing this review is to critically reevaluate the relevant literature and provide others with a "state-of-the-art" snapshot of choline-type esterquats and betaine-type esterquats. Hence, the first part of this survey thoroughly summarizes the most important scientific reports demonstrating effective synthesis routes leading to the formation of both types of esterquats. In the second section, the susceptibility of esterquats to hydrolysis is explained, and the influence of various factors, such as the pH, the degree of salinity, or the temperature of the solution, was subjected to thorough analysis that includes quantitative components. The next two sections refer to various aspects associated with the ecotoxicity of esterquats. Consequently, their biodegradation and toxic effects on microorganisms are extensively analyzed as crucial factors that can affect their commercialization. Then, the reported applications of esterquats are briefly discussed, including the functionalization of macromolecules, such as cotton fabric as well as their successful utilization on a commercial scale. The last section demonstrates the most essential conclusions and reported drawbacks that allow us to elucidate future recommendations regarding the development of these promising chemicals. [ABSTRACT FROM AUTHOR]

Myristyl-γ-picolinium chloride (MGPC) is an alkyl pyridine quaternary ammonium salt and a popular preservative in injectables such as Depo-Medrol (Methylprednisolone acetate). Herein we describe a successful high-p,T,c chemical intensification of MGPC synthesis from neat myristyl chloride and γ-picoline in continuous flow. The process is atom economical, scalable with low reactor footprint and under optimized conditions, consistently affords MGPC in 45 min (instead of 8–12 h reported in literature for a conventional batch process) with excellent yield (> 90%) and purity (> 99%). [ABSTRACT FROM AUTHOR]

The preparation of two tri-iodide salts, C7H11N2+·I3−·0.5H2O (1) and (C2H5)4N+·I3− (2), synthesized by the slow diffusion method in solution, is reported. Their structures have been characterized by means of single-crystal X-ray diffraction. They consist of two different arrangements of tri-iodide ions, organized in a one-dimensional linear chain for 1 and in two-dimensional T-shaped sheets for 2, stabilized by 4-dimethylaminopyridinium and tetraethylammonium ligands. An asymmetry of the tri-iodide anions is observed in both structures, and is associated to the I⋯I halogen and hydrogen bonding interactions. The generation of the resulting supramolecular networks for these compounds was found to be driven by hydrogen-bond assisted self-assembly. The crystal structures of the two compounds were found to be supported essentially by H⋯I interactions between organic molecules and tri-iodide anions. For compound 2, an additionally stabilization by O⋯H/H⋯O interactions due to the presence of water molecules occurs. The dominant intermolecular interactions and their directionality have been examined by Hirshfeld surfaces and fingerprint analysis. Both compounds were characterized further by FT-IR and Raman spectroscopy, TGA/DTG and UV-visible absorption by means of thin film methods. The target compounds were also studied computationally using density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches to explore their potential performances and to rationalize the experimental results. An electronic transition from 3σg to has been proven to dominate intramolecular charge transfer occurring for both 1 and 2. This electronic communication leads to an HOMO–LUMO energy gap of 4.208 eV for 1 and 4.255 eV for 2. [ABSTRACT FROM AUTHOR]

Amino acid-derived quaternary ammonium salts were successfully applied in the asymmetric aza-Henry reaction of nitromethane to N-Boc trifluoromethyl ketimines. a-Trifluoromethyl p-nitroamines were synthesized in good to excellent yields with moderate to good enantioselectivities. This reaction is distinguished by its mild conditions, low catalyst loading (1 mol%), and catalytic base. It also proceeded on a gram scale without loss of enantioselectivity. The products were transformed to a series of adamantane- type compounds containing chiral trifluoromethylamine fragments. The potent anticancer activities of these compounds against liver cancer HepG2 and melanoma B16F10 were evaluated. Six promising compounds with notable efficacy have potential for further development. [ABSTRACT FROM AUTHOR]

The use of molecular photoswitches has spread to virtually every field of pure and applied chemistry because of the extraordinary level of control they provide over the behavior of matter at the smallest scales. Photoswitches possess at least two different states with distinct structures and/or electronics and further functionalization of their core chromophore structures is needed to tailor them for a specific application. In this work we present a different concept for the generation and use of molecular photoswitches. It allows not only simultaneous establishment of photochromism and functionalization, but also full recyclability of a non‐photochromic precursor material. Using a high‐yielding and reversible ammonium salt formation, a functional group is introduced into a symmetric precursor while at the same time a strong electronic push‐pull character is established in the structure. The resulting desymmetrization leads to efficient photoswitching capacity and the functional group can be fully removed subsequently by a simple heating step recovering the precursor for another functionalization round. We finally demonstrate feasibility of this concept over two consecutive closed loop functionalization/photoswitching/recovery steps. This concept offers great potential in any chemical research and application driven area but especially for the creation of responsive reprogrammable materials, no‐background photoswitch labeling, and sustainable chemistry. [ABSTRACT FROM AUTHOR]

This review provides a comprehensive overview of mono‐alkylation methodologies targeting crucial nitrogen moieties – amines, amides, and sulfonamides – found in organic building blocks and pharmaceuticals. Emphasizing the intersection of chemical precision with drug discovery, the central challenge addressed is achieving one‐pot mono‐selective short‐chain N‐alkylations (methylations, ethylations, and n‐propylations), preventing undesired overalkylation. Additionally, sustainable, safe, and benign alternatives to traditional alkylating agents, including alcohols, carbon dioxide, carboxylic acids, nitriles, alkyl phosphates, quaternary ammonium salts, and alkyl carbonates, are explored. This review, categorized by the nature of the alkylating agent, aids researchers in selecting suitable methods for mono‐selective N‐alkylation. [ABSTRACT FROM AUTHOR]

The air filtration materials with high efficiency, low resistance, and extra antibacterial property are crucial for personal health protection. Herein, a tree‐like polyvinylidene fluoride (PVDF) nanofibrous membrane with hierarchical structure (trunk fiber of 447 nm, branched fiber of 24.7 nm) and high filtration capacity is demonstrated. Specifically, 2‐hydroxypropyl trimethyl ammonium chloride terminated hyperbranched polymer (HBP‐HTC) with near‐spherical three‐dimensional molecular structure and adjustable terminal positive groups is synthesized as an additive for PVDF electrospinning to enhance the jet splitting and promote the formation of branched ultrafine nanofibers, achieving a coverage rate of branched nanofibers over 90% that is superior than small molecular quaternary ammonium salts. The branched nanofibers network enhances mechanical properties and filtration efficiency (99.995% for 0.26 µm sodium chloride particles) of the PVDF/HBP‐HTC membrane, which demonstrates reduced pressure drop (122.4 Pa) and a quality factor up to 0.083 Pa−1 on a 40 µm‐thick sample. More importantly, the numerous quaternary ammonium salt groups of HBP‐HTC deliver excellent antibacterial properties to the PVDF membranes. Bacterial inhibitive rate of 99.9% against both S. aureus and E. coli is demonstrated in a membrane with 3.0 wt% HBP‐HTC. This work provides a new strategy for development of high‐efficiency and antibacterial protection products. [ABSTRACT FROM AUTHOR]

A series of quaternary ammonium or phosphonium salts were applied as zeolite growth modifiers in the synthesis of hierarchical ZSM-5 zeolite. The results showed that the use of methyltriphenylphosphonium bromide (MTBBP) could yield nano-sized hierarchical ZSM-5 zeolite with a "rice crust" morphology feature, which demonstrates a better catalytic performance than other disinfect candidates. It was confirmed that the addition of MTBBP did not cause discernable adverse effects on the microstructures or acidities of ZSM-5, but it led to the creation of abundant meso- to marco- pores as a result of aligned tiny particle aggregations. Moreover, the generation of the special morphology was believed to be a result of the coordination and competition between MTBBP and Na+ cations. The as-synthesized hierarchical zeolite was loaded with Zn and utilized in the propane aromatization reaction, which displayed a prolonged lifetime (1430 min vs. 290 min compared with conventional ZSM-5) and an enhanced total turnover number that is four folds of the traditional one, owing to the attenuated hydride transfer reaction and slow coking rate. This work provides a new method to alter the morphological properties of zeolites with low-cost disinfectants, which is of great potential for industrial applications. [ABSTRACT FROM AUTHOR]

The purpose of this research is to improve the stability of α-amylase from Aspergillus fumigatus by chemical modification with citraconic anhydride. The α-amylase was isolated using a centrifugation technique, followed by purification using precipitation and dialysis of ammonium sulfate salt. The experimental results demonstrate that the purity of purified α-amylase is 13.41 times higher than that of the crude extract. A significant increase in the optimum temperature was also achieved, in which the optimum temperature of 50 °C was found for native α-amylase, while for modified α-amylase, the optimum temperature of 60 °C was found. Similarly, an increase in half-life was also evident, which is 38.72 min found for the native enzyme to 256.67–330.00 min for modified α-amylase, depending on the volume of citraconic anhydride used. Modification also resulted in increased free energy values (ΔGi) from 104.348 for the native enzyme to 109.585–110.281 kJ mol−1 for modified α-amylase, indicating that modified α-amylase is stiffer than native α-amylase. The results obtained in this work demonstrate that citric anhydride is a very promising modifying agent to improve the stability and performance of α-amylase enzyme isolated from A. fumigatus. The findings of this study also offer an opportunity for the application of citric anhydride for other enzymes. [ABSTRACT FROM AUTHOR]

The double skeleton interpenetrating network fixed the quaternary ammonium salt, and various internal conduction modes cooperated to promote the transport of hydroxide ions. [Display omitted] The alkaline solid-state electrolytes have received widespread attention for their good safety and electrochemical stability. However, they still suffer from low conductivity and poor mechanical properties. Herein, we report the synthesis of double-network featured hydroxide-conductive membranes fabricated by polyvinyl alcohol (PVA) and chitosan (CS) as the double-skeletons. Then, we implanted quaternary ammonium salt guar hydroxypropyltrimonium chloride (GG) as the OH− conductor for high-performance electrochemical devices. By virtue of the unique stripe-like structure shared from the double skeleton with a high degree of compatibility and stronger hydrogen bond interactions, the polyvinyl alcohol/chitosan-guar hydroxypropyltrimonium chloride (PCG) solid-state electrolytes achieved optimal thermal stability (> 300 °C), mechanical property (∼ 34.15 MPa), dimensional stability (at any bending angle), and high ionic conductivity (13 mS cm−1) and ion mobility number (t ion ∼ 0.90) compared with chitosan-guar hydroxypropyltrimonium chloride (CG) and polyvinyl alcohol-guar hydroxypropyltrimonium chloride (PG) electrolyte membrane. As a proof-of-concept application, the "sandwich"-type zinc-air battery (ZAB) assembled using PCG membrane as the electrolyte realized a high open-circuit voltage (1.39 V) and an excellent power density (128 mW cm−2). Notably, in addition to its long-term cycle life (30 h, 2 mA cm−2) and stable discharge plateau (12 h, 5 mA cm−2), it could even enable a flexible ZAB (F-ZAB) to readily power light-emitting diodes (LED) at any bending angle. These merits afford the PCG membrane a promising electrolyte for improving the performance of solid-state batteries. [ABSTRACT FROM AUTHOR]

Low-permeability sandstone reservoirs with low clay content are prone to water-sensitive damage during the fracturing process. In field applications, serious formation damage occurred with the conventional fracturing fluid system using KCl clay stabilizer. The introduction of SP clay stabilizer into the fracturing fluid formulation system significantly reduced the water-sensitive damage during fracturing and improved the reservoir transformation and production enhancement effect. In this paper, the clay stabilization mechanism of two substances, inorganic clay stabilizer KCl and organic ammonium salts with low molar weight SP, is studied by tests of swelling inhibition, ζ-potential test, and scanning electron microscope test to compare. On this basis, the adsorption behavior of SP on the surface of clay minerals is also studied in depth by isothermal adsorption and desorption experiments to explain mechanistically the difference of two different clay stabilizers on the fracturing effect, which helps to solve the formation damage problem in the fracturing and production enhancement process of low-permeability sandstone reservoirs with low clay content. [ABSTRACT FROM AUTHOR]

Quaternary ammonium salts of metal derivatives of polyoxometalates [XW11O39M(H2O)]n− (X = P, Si; M = Cr, Mn, Co, Ni, Zn) were successfully tested instead of quaternary ammonium halides as catalysts in the cycloaddition of CO2 to styrene oxide. Remarkably, they gave very satisfactory yields of styrene carbonate at moderate temperature (80 °C). [ABSTRACT FROM AUTHOR]

Fixing the greenhouse gas CO2 through epoxide helps to mitigate worldwide ecological troubles. The applications of metal‐free and solvent‐free catalysts remain a challenge for CO2 catalytic conversion. In this work, an array of quaternary ammonium salts derived from polyethyleneimine with hydroxyl groups ([PEI‐GDMAB‐Cn]Br) were constructed by the reaction of branched PEI with a molecular weight of 10000 and glycidyl alkyl dimethylammonium bromide. A range of experiments were designed to demonstrate that [PEI‐GDMAB‐Cn]Br can be considered as a valid metal‐free and solvent‐free homogeneous catalyst for the CO2‐epoxide cycloaddition reaction. Among of [PEI‐GDMAB‐Cn]Br, [PEI‐GDMAB‐C18]Br catalyzed the model reaction of CO2 and epichlorohydrin under optimized reaction conditions (T=80 °C, 1.0 atm CO2, catalyst 1 mol%, ECH 15 mmol, 16 h) and the conversion achieved at 97.5 %. Moreover, the catalyst exhibited stable reusability and broad substrate applicability, which was used in the following cycle succinctly, because of self‐separated properties by temperature control. The [PEI‐GDMAB‐C18]Br catalyzed reaction process was detected as a pseudo‐first‐order reaction after kinetic studies and an Ea was calculated to be 50.65 kJ/mol. A combinatorial catalytic mechanism of hydrogen bonding and bromide ions is suggested to explain the remarkable catalytic performance of this bifunctional catalyst. [ABSTRACT FROM AUTHOR]

This article provides a summary of the progress made in the enantioselective synthesis of axially chiral cycloalkylidenes. Chiral structures are important in natural products and drug molecules, and the construction of chiral structures is a key topic in organic chemistry. The article explores various methods for the synthesis of chiral cycloalkylidenes, including asymmetric reactions such as Horner-Wadsworth-Emmons reactions and transition-metal-catalyzed reactions. The potential applications of these compounds in fields such as circular dichroism research and liquid-crystal-based optical switches are also discussed. However, the widespread application of these compounds is limited due to the requirement of stoichiometric chiral reagents or auxiliaries, and further research is needed to develop more effective strategies for their synthesis. [Extracted from the article]

Water-soluble ammonium salts were prepared by the reaction of new sterically hindered isatin derivatives with analogues of Girard's reagents. The resulting isatin-3-hydrazones exhibit high antimicrobial and antiaggregation activity with low hemotoxicity. The dependence of physiological activity on the volume of the benzyl substituent was established. [ABSTRACT FROM AUTHOR]

With the (re)advent of eutectic mixtures within the field of deep eutectic solvents, special attention has been given to the measurement of solid–liquid equilibrium (SLE) phase diagrams, supported by the relevant information they can provide on the molecular interactions and melting temperature depression of any given system. As such, this work investigates the SLE phase diagrams of mixtures between ionic liquids and tetraalkylammonium chlorides (methyl, ethyl, and propyl), with the goal of decreasing the melting temperature of ionic liquids and ammonium salts, thus, expanding their application scope. Results show that tetraalkylammonium salts exhibit negative deviations from thermodynamic ideality when mixed with ionic liquids, which are increased by increasing their alkyl chain length and are interpreted in terms of anion exchange mechanisms. In turn, this nonideality contributes greatly to depression of the melting point of the ionic liquids examined. Overall, this work demonstrates that the correct combination of tetraalkylammonium/ILs anions and cations can lead to significant melting point depressions in both species, thus creating new ionic liquid mixtures using an approach akin to that used to form deep eutectic solvents. [ABSTRACT FROM AUTHOR]

The selective fixation of CO2 and epoxides into cyclic carbonates offers an atom-economical approach towards promising utilization of anthropogenic CO2 gas. This work demonstrates the development of recyclable organic–inorganic hybrid TBAI@CuO catalyst containing quaternary ammonium (TBAI) salt as active organic groups and CuO flowers as the inorganic component. Initially, CuO flowers was synthesized using a simple oxidation-precipitation method followed by immobilization of TBAI groups using impregnation method. The impregnated TBAI groups functioned as the active basic centers, whereas CuO flowers with effective surface area provided heterogeneity, Lewis acidic sites, facilitated better dispersion and strong interaction of TBAI. Resultantly, hybrid TBAI@CuO catalyst consisted of dual-active sites which played a decisive role in manipulating catalytic activity without requirement of a co-catalyst. With styrene oxide and CO2 as model substrates, the present catalyst system delivered 95% conversion and 97% selectivity towards styrene carbonate under solvent-free and milder reaction conditions when compared to other single metal oxide catalysts. The homogeneously dispersed TBAI groups in strong interaction with CuO flowers provided simultaneous access to both Lewis acidic as well as basic sites and hence resulted in superior catalytic activity. Meanwhile, hybrid TBAI@CuO catalyst showed catalytic adequacy for various terminal and internal epoxides. This catalytic system also presented good reusability without prominent loss in activity and no leaching of active TBAI groups. Based on characterization results, a plausible reaction mechanism was predicted to support the cycloaddition reaction with hybrid TBAI@CuO catalyst. It was proposed that inorganic Lewis acidic CuO activated the epoxide whereas the immobilized TBAI groups activated the inert CO2 molecule and stabilized the epoxide after ring opening. Therefore, the CuO flowers acting in concert with the immobilized TBAI groups showed exceptional acid–base cooperativity and provided high selectivity towards cyclic carbonates. The hybrid TBAI@CuO catalyst in this effort bridges the gap between homogeneous and heterogeneous catalysis for sustainable transformation of CO2 and epoxides to cyclic carbonates under solvent-free and comparatively mild reaction conditions [ABSTRACT FROM AUTHOR]

In the article, the results of the study of the quaternary ammonium salt formed by hexadecanoic acid, a monobasic carbonic acid, with monoethanolamine, in laboratory conditions, in distilled, drinking, and sea waters contaminated with Balakhani oil with different degrees of mineralization, are given. The surface activity property of the products of different concentrations of this complex was studied using a tensiometer, the element composition was calculated by calculation, and the composition and structure were confirmed by infrared spectroscopy. The result of investigating the composition of the complexes formed by hexadecanoic acid with monoethanolamine by infrared spectroscopy proves that the reaction proceeds according to the scheme indicated in the article. As a result of the research, it was determined that the mass share of carbon in the salt obtained on the basis of hexadecanoic acid and monoethanolamine is 68%, the share of hydrogen is 12.6%, the share of oxygen is 15%, and the share of nitrogen is 4.4%. The salt obtained on the basis of hexadecanoic acid and monoethanolamine shows high surface activity by reducing the surface tension at the water-air interface from 71.98 mN/m to 30.9 mN/m. The synthesized reagent has strong oil-collecting and oil-dispersing properties. With the application of this complex, it is possible to remove thin layers of oil from the water surface. The obtained complex is well soluble in ethyl and isopropyl alcohols. [ABSTRACT FROM AUTHOR]

Particulate matter (PM), usually formed as aerosols suspended in atmosphere, is becoming a carrier of viruses and bacteria, accelerating the spread of respiratory diseases. Hence, air filtration devices are widely utilized for removing PM. In this study, a regenerated cellulose (RC) film was prepared with the properties of good mechanical strength, antibacterial, and highly efficient filtration (EF) properties, through cellulose dissolution and further crosslinking with P(AGE-DMDAAC)/ZnO. Results exhibited that the Young's modulus of the composite membrane was nearly 4.3 GPa. Additionally, the antibacterial performance against Escherichia coli and Staphylococcus aureus, was up to 99.89% and 99.67%, respectively. Meanwhile, RC composite filter exhibited a high PM 2.5 capture efficiency (over 99.91%). This study introduces an interesting approach to produce antibacterial films with the characteristics of notably good mechanical performance and high fine particle EF that can be utilized in a high humidity environment. [ABSTRACT FROM AUTHOR]

This work presents the synthesis of alginate-coated magnetite nanoparticle (MNP) containing aminoenriched moieties for the immobilization of palladium (Pd), and its use as a recyclable catalyst for the reduction of 4-nitrophenol (4NP) in water. The alginate grafted onto the surface of MNP contained carboxylate anions that served as coordination sites for Pd. Additionally, the incorporation of aminoenriched components, such as poly(vinyl amine) (PVAm) and 2-(dimethyl amino)ethyl methacrylate (DMAEMA), onto the alginate-coated MNPs resulted in additional interactions, including the formation of carboxylate-ammonium salts. In this study, the influence of these amino groups on the efficiency of Pd immobilization, catalytic activity and reusability of nanosorbents for 4NP reduction was investigated. The existence of Pd in the nanosorbents was detected by inductively coupled plasma atomic emission spectroscopy, transmission electron microscopy, and energy-dispersive X-ray techniques. The average size of MNPs was approximately 12.3 ± 2.9 nm, and for Pd, it was about 3.9 ± 0.8 nm. It was found that the incorporation of these amino-enriched moieties into the particles significantly enhanced the catalytic activity of the nanosorbents. Notably, MNP containing extended DMAEMA units exhibited excellent tolerance to 4NP reduction, with an insignificant loss of catalytic performance even after 20 consecutive reuses, maintaining a conversion of over 98 %. [ABSTRACT FROM AUTHOR]

The antioxidant activity of chitosan (CS) and three water-soluble derivatives was analyzed comparatively by in vitro and in vivo experiments, including hydroxypropyl chitosan (HPCS), quaternary ammonium salt of chitosan (HACC), and carboxymethyl chitosan (CMCS). The results show that chitosan and its water-soluble derivatives have a scavenging ability on DPPH radicals, superoxide radicals, and hydroxyl radicals, and a reducing ability. A remarkable difference (p < 0.05) was found for HACC and HPCS compared with CS on DPPH radicals, hydroxyl radicals, and reducing ability. The antioxidant ability of the four chitosan samples was in the order of HPCS > HACC > CMCS > CS. Furthermore, antioxidant activity of all samples increased gradually in a concentration-dependent manner. The in vivo result indicates that oral CS and its derivatives samples result in a decrease in lipid peroxides (LPO) and free fatty acids (FFA) levels in serum with an increase in superoxide dismutase (SOD) activity. Especially for the HPCS and HACC groups, the LPO, FFA, and SOD activity in serum was different significantly in comparison with the high-fat controlgroup (HF) (p < 0.05). These results indicate that chitosan and its derivatives can be used as good antioxidants, and the antioxidant activity might be related to the molecular structure of chitosan derivatives. [ABSTRACT FROM AUTHOR]

At present, one of the major factors limiting the further improvement of inverted (p‐i‐n) perovskite solar cells (PSCs) is trap‐assisted non‐radiative recombination at the perovskite/electron transporting layer (ETL) interface. Surface passivation with organic ammonium salt is a powerful strategy to improve the performance of PSCs. Herein, an effective method by using propylamine hydroiodide (PAI) and 1,3‐diaminopropane dihydroiodide (PDADI) is reported to modify the perovskite/ETL interface. These two ammonium salts do not form new perovskite but directly passivate the defects on the perovskite surface after annealing. The results show that the PDADI‐modified perovskite films possess a lower surface defect density and less non‐radiative recombination as well as improved charge carrier transport. Based on this strategy, the PDADI‐modified p‐i‐n PSCs deliver an impressive efficiency of 25.09% (certified 24.58%) with an open‐circuit voltage of 1.184 V. Furthermore, the unencapsulated PDADI‐modified PSCs also exhibit good storage stability, retaining 91% of initial PCE at 65 °C in a N2 glove box for 1300 h. This strategy provides an efficient route to fabricate highly efficient and stable inverted p‐i‐n structured PSCs. [ABSTRACT FROM AUTHOR]

The rational synthesis of zeolites with designed morphology is a highly challenging task. In this study, we propose 1,5-bis(methylpiperidine)pentylammonium hydroxide (BMPPAOH) as an organic structure-directing agent (OSDA) based on theoretical calculations. The morphology of zeolite samples is characterized by XRD, SEM, TEM, N2 sorption isotherms, and UV Raman spectroscopy. This simple bis-quaternary ammonium salt favored the formation of spiral morphology in Beta zeolite spheres (S-Beta). The crystallization of zeolite in the presence of BMMPAOH is a two-stage process, where nanoparticles agglomerate into spheres in the early stages followed by the emergence of S-Beta crystals with spiral morphology. The synthesized Pt-S-Beta catalysts show higher catalytic activity in VOC abatement compared with other Pt-Beta samples. [ABSTRACT FROM AUTHOR]

Electrospray ionization mass spectrometry (ESI-MS) analysis is frequently associated with noncovalent adduct formation, both in positive and negative modes. Anion binding and sensing by mass spectrometry, notably more challenging compared to cation binding, will have major research potential with the development of appropriate sensors. Here, we demonstrated identification of stable bisquaternary dication adducts with trifluoroacetate (TFA−), Cl− and HSO4− in positive-mode ESI-MS analysis. The observed adducts were stable in MS/MS mode, leading to the formation of characteristic fragment ions containing a covalently bound anion, which requires bond reorganization. This phenomenon was confirmed by computational methods. Furthermore, given that anion detection and anion sensor chemistry have gained significant prominence in chemistry, we conducted an analysis of the fluorescent properties of bisquaternary ammonium compound as a potential anion sensor. [ABSTRACT FROM AUTHOR]

Controllable fluorination of silicate materials has been hardly accomplished mainly due to the high reactivity of fluorinating substances. In this study, the introduction of fluorinating substances into the interlayer space of magadiite in neutral form was attempted to induce an in situ fluorination reaction preferably on the interlayer surface of layered silicates. Two types of fluorinating substances, inorganic ammonium fluoride salts and organic 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride (Floulead), were successfully intercalated into the interlayer space of magadiite without any significant deterioration of the framework. Subsequent in situ fluorination reactions led to the preferred fluorination of the layered silanol groups that was envisioned successfully in the XRD pattern, FT-IR spectrum, TG/DTA curve, and cation exchange capacity. This study demonstrates that the silicate materials could be fluorinated selectively through intercalation and subsequent in situ localized reactions of various fluorinating substances. [ABSTRACT FROM AUTHOR]

New ammonium hydrazones have been synthesized by the reaction of Girard's reagents T and P with isatin derivatives that contain various alkyl or geranyl substituents in position 1. A pronounced anti-anthropo- and antiphyto-pathogenic effect of resulting compounds has been revealed. The n-octyl and octadiene derivatives have the highest selectivity for resistant strains of Staphylococcus aureus when there is no negative effect on the hemostasis system. The aggregation and adsorption properties of the compounds have been studied using tensiometry, conductometry, and UV spectroscopy. The found values of the critical micelle concentration of amphiphilic ammonium hydrazones are an order of magnitude lower than those of quaternary ammonium salts. [ABSTRACT FROM AUTHOR]

Wood is a naturally porous material prone to microbial erosion and degradation in outdoor environments. Therefore, the development of an environmentally friendly wood preservative with excellent antibacterial effects and low toxicity is urgently needed. In this study, nitrogen-doped carbon quantum dots (N-CQDs) with excellent antifungal performance and fluorescent properties were synthesized using a one-step hydrothermal method with chitosan quaternary ammonium salt (HACC) as the raw material. The fluorescence characteristics of N-CQD preservatives can help track their position and distribution in wood. The minimum inhibitory concentration (MIC) of N-CQDs is 1.8 mg/mL, which was nearly 22 times lower than that of HACC (40.0 mg/mL) in the PDA medium. The decay resistance test demonstrated that wood treated with N-CQDs showed a considerably reduced decay degree and its mass loss rate decreased from 46 ± 0.5% to 3.8 ± 0.5%. Biological transmission electron microscopy revealed that N-CQDs effectively destroyed fungal cell structures, thereby hindering the growth of Coriolus versicolor. N-CQDs synthesized using the one-step hydrothermal method can be used as an efficient wood preservative that can effectively improve the utilization and service life of wood. [ABSTRACT FROM AUTHOR]

The structures of five ammonium salt forms of monosulfonated azo dyes, derivatives of 4‐(2‐phenyldiazen‐1‐yl)benzenesulfonate, with the general formula [NH4][O3S(C6H4)NN(C6H3)RR′]·XH2O [R = OH, NH2 or N(C2H4OH)2; R′ = H or OH] are presented. All form simple layered structures with alternating hydrophobic (organic) and hydrophilic (cation, solvent and polar groups) layers. To assess for isostructural behaviour of the ammonium cation with M+ ions, the packing of these structures is compared with literature examples. To aid this comparison, the corresponding structures of four potassium salt forms of the monosulfonated azo dyes are also presented herein. Of the five ammonium salts it is found that three have isostructural equivalents. In two cases this equivalent is a potassium salt form and in one case it is a rubidium salt form. The isostructurality of ion packing and of unit‐cell symmetry and dimensions tolerates cases where the ammonium ions form somewhat different interaction types with coformer species than do the potassium or rubidium ions. No sodium salt forms are found to be isostructural with any ammonium equivalent. However, similarities in the anion packing within a single hydrophobic layer are found for a group that consists of the ammonium and rubidium salt forms of one azo anion species and the sodium and silver salt forms of a different azo species. [ABSTRACT FROM AUTHOR]

γ-Al 2 O 3 with a high density of active sites has been widely used. In this study, γ-Al 2 O 3 powder with a high specific surface area and a high purity is prepared through facile ammonium salt-assisted calcination. During the calcination process, the gases (NH 3 and CO 2) generated from ammonium salts can manipulate the pore and crystal structures to obtain active γ-Al 2 O 3 with a high purity of above 99.99 %. The results demonstrate that the specific surface areas of γ-Al 2 O 3 obtained by the use of ammonium carbonate (AC), ammonium bicarbonate (AB), and ammonium acetate (AA) are 441.35, 459.23, and 427.32 m2 g−1, respectively. Moreover, the γ-Al 2 O 3 obtained with ammonium salt shows a higher content of AlO 6 than the blank group, contributing to the formation of a sponge-like morphology and more active sites. Furthermore, the active γ-Al 2 O 3 exhibits good performance in adsorption and desorption, making it highly valuable in various applications. [ABSTRACT FROM AUTHOR]

We herein report a protocol for the asymmetric 1,4‐addition of hydantoins to various Michael acceptors by utilizing Cinchona alkaloid‐based chiral quaternary ammonium salt catalysts. Various products were obtained with moderate to good enantioselectivities and accompanying computational investigations helped to identify key interactions responsible for the observed selectivity. DFT calculations along with non‐covalent interaction plots reveal the presence of numerous stabilizing non‐classical hydrogen bonding interactions along with other non‐covalent interactions between the chiral quaternary ammonium salt and hydantoin molecule in the C−C bond forming transition states leading to the formation of the products. In addition, a first proof‐of‐concept for an analogous a‐sulfanylation reaction, albeit with poor selectivity, is reported as well. [ABSTRACT FROM AUTHOR]

Additive manufacturing is still the fastest-developing technology in the modern world. Three-dimensional printing has become popular due to the method's numerous advantages, such as its short time and low cost, compared to conventional methods such as injection molding. Therefore, the demand for new materials and material systems that will be characterized by the desired functional properties is clearly growing. As part of this work, work was carried out on the development and preparation of new polymer composites dedicated to 3D printing applications, especially in FDM/FFF/MEM technologies. The influence of the content and amount of fillers, such as silica modified with alumina (S) and bentonite modified with a quaternary ammonium salt (B), on the functional properties of a commercially available fiber made of traditional plastic, such as polycarbonate, obtained in the form of a filament (PCF), was determined. It was found that the addition of B significantly increased the fluidity of the polymer, the introduction of a filler in the amount of 1.5% allowed to obtain a result that was 6% higher compared to PCF (16.8 g/10 min), while the amount of 3% was 20% higher. The obtained mass melt flow rate (MFR) results were confirmed by determining the viscosity of the produced polymer composites. Satisfactory results of mechanical properties were obtained, including the following: it was found that the introduced modified fillers increased the elasticity of the material. The introduction of modified silica resulted in a reduction in Young's modulus by 10.02% at the content of 0.5% S and at 1% S by 8.64% compared to the polymer. The introduced modified filler S significantly increased the thermostability of polycarbonate (T5% equal to 449 °C) by 23 °C for PCF/0.5% S and 14 °C for PCF/1% S, respectively. The SEM and WAXS results confirmed the appropriate dispersion of the fillers in the polymer matrix, which indicates well-selected conditions for the homogenization process of the components and the subsequent production of samples. Detailed characterization of the influence of selected fillers on the functional properties of the polymer matrix-polycarbonate allowed for an increase in the range of polymer composites and their use in rapid prototyping technologies, as well as supplementing the literature on databases regarding the characteristics of the obtained materials. [ABSTRACT FROM AUTHOR]

Polybutylene terephthalate (PBT) nanocomposites loaded with two different types of organoclays are fabricated using the melt mixing technique in a twin-screw extruder. Quaternary ammonium salts with dimethyl, benzyl, hydrogenated tallow, and dimethyl, dehydrogenated tailed modified organoclays are blended with PBT matrix at the compositions of 1%, 3%, 5%, and 10% weight ratios. Test samples are shaped using a lab-scale injection molding device. Mechanical, thermo-mechanical, thermal stability, melt flow, structural, and morphological behaviors of the nanocomposite samples are investigated by performing tensile, impact, and shore hardness tests, dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA), melt flow rate measurements, X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM) methods, respectively. According to the findings, NC 130 clay gave better results than NC 140 in terms of tensile, hardness, and melt flow behaviors, whereas NC 140 showed higher performances as impact resistance, thermo-mechanical, and density, since the reduction in density and weight lowering are highly required for mainly transportation sector, and thermal properties were considered. [ABSTRACT FROM AUTHOR]