Ammonium Carboxylate Research Articles

Investigation of synthesis of some ionic liquids from nitrogen compounds and fatty acids of waste oils

In order to reduce the environmental pollution and the dependence on fossil fuel resource which is depleting, the utilization of waste vegetable oils for preparation of valuable products are of concern. Four ionic liquids triethyl ammonium carboxylate ([TEA][WO]), octyl ammonium carboxylate ([OcA][WO]), trialkyl methyl ammonium carboxylate ([Aliquat][WO]) and n-octyl methyl imidazolium carboxylate ([OMIM][WO]) were synthesized from four different nitrogen compounds and fatty acids of waste vegetable oils. The influence of some parameters such as solvent, reaction temperature, reaction time and molar ratio of acid and nitrogen compound (NC) on ionic liquid synthesis yields was investigated. The results show that the structure of nitrogen compounds effects on the synthesis performance and governs the parameters of processes. This is due to the nitrogen compounds as starting materials control not only their activity in reaction with fatty acids but also the solubility and the melting points of corresponding ionic liquids. Certain suitable conditions were chosen for each ionic liquid.

Room temperature self-healable ionic polymers by incorporating ammonium and carboxylate salt

In this study, we report the fabrication and characteristics of a self-healing polymer forming an ionically bonded network based on carboxylic acids and alkyl amines. The self-healing polymer forming an ionically bonded network is prepared from acrylic acid-containing carboxylic groups in the main chain and ammonium carboxylate salts derived from alkyl amines of varying lengths. The nature of the ion bonding between alkyl amines and carboxylic acids within the polymer matrix was analyzed using Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FT-IR). The self-healing polymer, incorporating ionically bound entities like ammonium carboxylate salts, demonstrated 100% self-healing efficiency at room temperature overnight, in contrast to the reference polymer without ion bonding. Various lengths of alkyl amines used to form ammonium carboxylate salts exhibited remarkable properties such as over 500% elongation at break, adhesive strength exceeding 300 gf, and light transmittance of over 90%, all dependent on the length of the alkyl chain.

Concentration-tuned diverse response to selective biogenic amines using a reusable fluorophore: monitoring protein-rich food spoilage.

Maintaining the freshness of food is essential for a healthy and quality life. Nevertheless, it remains a global challenge. Hence, an easy detection and monitoring protocol would be highly desirable. A cyanoacrylic acid (CAA)-based fluorophore is manifested as a reusable platform that responds diversely against different concentrations of selective aliphatic biogenic amines (BAs) in both solution and vapor phases. Slow spoilage of the protein-rich food is progressively monitored through emission shifts visible to the naked eye. This fluorophore provides easy and naked-eye detection of the BA vapor through a change in emission, i.e., red → orange → orange-yellow → cyan → green and quantum yield enhancement, which occur in stepwise increments of vapor concentrations. The probe design includes π-conjugated functionalized fluorescent molecules linked to multiple twisting sites, resulting in both solid and solution-state emission. The attached carboxylic acid responds quickly with selective BAs, mainly putrescine (PUT), cadaverine (CAD), and spermidine (SPM), where the concentration-based emission variation has appeared to be distinct and prominent against PUT [sensitivity (μM): 2 (solution); 3.3 (vapour)]. The selectivity towards diamine can be clarified by the formation of carboxylic acid salts and the consequent proton exchanges between free and protonated amines. In addition, -CN···H interaction is likely to develop within this ammonium carboxylate system, providing extra stability. Such ammonium carboxylate salt formation and gradual change in the molecular arrangement, resulting in symmetry development, are validated by FT-IR and wide-angle X-ray diffraction studies. Besides, this fact is supported by DFT studies that validate intramolecular H-atom exchange between free amine and ammonium salt units. A fluorophore-coated coverslip, filter paper, or silica gel-coated Al-plate is fruitfully utilized to detect the freshness of fish and chicken, which reveals the potential of this probe to prevent food waste and control food safety.

Ammonium carboxylates in the ammonia-Ugi reaction: one-pot synthesis of α,α-disubstituted amino acid derivatives including unnatural dipeptides.

Despite the remarkable developments of the Ugi reaction and its variants, the use of ammonia in the Ugi reaction has long been recognized as impractical and unsuccessful. Indeed, the ammonia-Ugi reaction often requires harsh reaction conditions, such as heating and microwave irradiation, and competes with the Passerini reaction, thereby resulting in low yields. This study describes a robust and practical ammonia-Ugi reaction protocol. Using originally prepared ammonium carboxylates in trifluoroethanol, the ammonia-Ugi reaction proceeded at room temperature in high yields and showed a broad substrate scope, thus synthesizing a variety of α,α-disubstituted amino acid derivatives, including unnatural dipeptides. The reaction required no condensing agents and proceeded without racemization of the chiral stereocenter of α-amino acids. Furthermore, using this protocol, we quickly synthesized a novel dipeptide, D-Leu-Aic-NH-CH2Ph(p-F), which exhibited a potent inhibitory activity against α-chymotrypsin with a Ki value of 0.091 μM.

Ammonium carboxylate salts: the additivity of intermolecular interaction energies in charged organic compounds

The supramolecular organization of organic salts has been widely researched, revealing recurring patterns in crystalline lattices that describe their supramolecular properties.

Super-Structured Wet-Adhesive Hydrogel with Ultralow Swelling, Ultrahigh Burst Pressure Tolerance, and Anti-Postoperative Adhesion Properties for Tissue Adhesion.

Wet-adhesive hydrogels have been developed as an attractive strategy for tissue repair. However, achieving simultaneously low swelling and high burst pressure tolerance of wet-adhesive hydrogels is crucial for in vivo application which remains challenges. Herein, a novel super-structured porous hydrogel (denoted as PVA/PAAc-N+ ) is designed via facile moisture-induced phase separation-solvent exchange process for obtaining porous polyvinyl alcohol (PVA) hydrogel as dissipative layer and in situ photocuring technology for entangling quaternary ammonium-functionalized poly(acrylic acid)-based wet-adhesive layer (PAAc-N+ ) with the porous surface of PVA layer. Benefitting from the ionic crosslinking between quaternary ammonium ions and carboxylate ions in PAAc-N+ wet-adhesive layer as well as the high crystallinity induced by abundant hydrogen bonds of PVA layer, the hydrogel has unique ultralow swelling property (0.29) without sacrificing adhesion strength (63.1kPa). The porous structure of PVA facilitates the mechanical interlock at the interface between PAAc-N+ wet-adhesive layer and tough PVA dissipative layer, leading to the ultrahigh burst pressure tolerance up to 493mm Hg and effective repair for porcine heart rupture; the PVA layer surface of PVA/PAAc-N+ hydrogel can prevent postoperative adhesion. By integrating ultralow swelling, ultrahigh burst pressure tolerance, and anti-postoperative adhesion properties, PVA/PAAc-N+ hydrogel shows an appealing application prospect for tissue repair.

Characterization of Particle Size Distributions and Water-Soluble Ions in Particulate Matter Measured at a Broiler Farm

The chemical composition and size distribution of particulate matter produced at broiler poultry houses is not well understood, so this is a novel study to understand the particulate size distributions at a poultry house as well as the ionic composition of the particulate matter using real-time methods. Two optical particle counters provided particle size distributions inside and outside the house. An ambient ion monitor and a particle-in-liquid sampler analyzed the ionic chemical composition of the particulate matter in the house while a scanning mobility particle sizer provided size information in the nanoparticle range. Ammonia concentrations in the house were measured using a chemical sensor. Ammonia concentrations in the house were consistently in the lower part of the per million range 2–20 ppm. The optical particle counter and ion chromatography measurements both showed a strong diurnal variation of particulate matter concentration in the house throughout the study, associated with the lights being on and animal activity. Particulate mass concentration inside the house was dominated by coarse mode particles as opposed to the outdoor sampler which showed much smaller sizes. A few new particle formation and growth events were observed in the house. Ionic constituents detected by chromatography made up a small fraction of the overall mass concentration. The composition of the ionic constituents was similar for most of the study with typical ions being ammonium, sodium, potassium, chloride, sulfate, nitrate, nitrite, phosphate, and several carboxylates (formate, acetate, propionate, and butyrate.) At the end of the study, bromide was also detected during the last several days. Overall, we determined that the ionic components of the particulate matter formed through secondary particle formation was small, but also that some ionic constituents can be associated with management practices.

Zwitterionic cellular polymer enabled reductive fixation of CO2 for N-methylation of amines

Using heterogeneous catalysts to promote the construction of the C–N bond between amines and CO2 under mild conditions is a challenge yet. Herein, we synthesized a novel zwitterionic polymer (PDDC) with a cellular structure via self-complexation of copolymer bearing both quaternary ammonium cation and carboxylate anion. PDDC was employed as a recyclable catalyst for N-methylation of atmospheric CO2 and various amines with hydrosilane as a reductant, affording more than 17 ​N-methylamines in good to excellent yields (up to 99%) under mild conditions. The behavior of PDDC in the reaction medium was disclosed by using a dynamic light scattering study, revealing that the decreased hydraulic radius of particle size contributes to exposing more active sites and increasing reaction activity. Utilizing a series of designed experiments and density functional theory calculations uncovered the crucial role of the prepared zwitterionic polymer during the reaction procedure of CO2 conversion.

Cation controlled rotation in anionic pillar[5]arenes and its application for fluorescence switch

Controlling molecular motion is one of hot topics in the field of chemistry. Molecular rotors have wide applications in building nanomachines and functional materials, due to their controllable rotations. Hence, the development of novel rotor systems, controlled by external stimuli, is desirable. Pillar[n]arenes, a class of macrocycles, have a unique planar chirality, in which two stable conformational isomers pR and pS would interconvert by oxygen-through-the-annulus rotations of their hydroquinone rings. We observe the differential kinetic traits of planar chirality transformation in sodium carboxylate pillar[5]arene (WP5-Na) and ammonium carboxylate pillar[5]arene (WP5-NH4), which inspire us to construct a promising rotary platform in anionic pillar[5]arenes (WP5) skeletons. Herein, we demonstrate the non-negligible effect of counter cations on rotational barriers of hydroquinone rings in WP5, which enables a cation grease/brake rotor system. Applications of this tunable rotor system as fluorescence switch and anti-counterfeiting ink are further explored.

Waste organic acid treatment with polyethyleneimine grafted polystyrene resin

AbstractOrganic acid is a kind of important fine chemicals with wide application, while impropriate discharges would cause serious damage to environment. In this report, two polyethyleneimine (PEI‐600, 1800) functionalized polystyrene (PS) resins were facilely prepared to remediate common organic acids. The heavier PEI‐1800 resulted in surprisingly lower nitrogen loading of PSPEI under optimal conditions due to more significant extra grafting. Therefore, PSPEI‐600 was used to adsorb two groups (aliphatic and aromatic) of eight common organic acids, and showed highest adsorptive capacities toward salicylic acid (SA) and trifluoroacetic acid (TFA). The adsorption of TFA was faster and was mainly due to strong acid–base interactions by forming ammonium carboxylate. SA possessed lower acidity, but its additional π‐π stacking and hydrogen bonding interactions with the PSPEI resin led to a slower but overall higher uptake. Kinetic studies indicated that both acid adsorptions conformed to pseudo‐second‐order kinetics, and the adsorption rate was controlled by intraparticle diffusion. The adsorptions followed Langmuir isotherms and were identified as a spontaneous endothermic process.

Triprotic Ammonium Oleate Ionic Liquid Crystal Lubricant for Copper-Copper Friction and Wear Reduction

The triprotic ammonium carboxylate ionic liquid crystal (2-hydroxyethyl)ammonium oleate (MO) has been studied as a neat lubricant and as a lubricant additive in two base oils, PAO6 and 100N. The lubricants have been used in commercially pure copper-OFHC copper balls on disk reciprocating sliding contact at room temperature. Neat MO presents a very good lubricating performance, with a friction coefficient of 0.06 and a wear rate of OFHC copper disk of 4.15 × 10−7 mm3/N·m. These results are, respectively, 94% and 98% lower than those obtained for PAO6, with similar reductions obtained with respect to 100N. MO has also been studied as an additive in 2wt.% proportion. The severe abrasive wear mechanism that takes place in the presence of neat base oils is reduced by the MO additive.

Base-functionalized polymeric chemisorbents for succinic acid recovery from aqueous solution

New base-functionalized polymers are synthesized and assessed for their ability to chemisorb succinic acid (SA) from dilute aqueous solution. A hydrogel comprised predominantly of poly(2-N,N-dimethylaminoethylacrylamide) absorbs 0.17 g·SA /g·polymer, representing just 21% of the maximum theoretical yield. The lower-than-expected basicity is attributed to confinement of polymer-bound amine functionality by the swollen crosslink network, which inhibits the solvation needed to stabilize ammonium carboxylate ion pairs. These gel effects are avoided by synthesizing a 1-vinyl-3-dodecylimidizolium based polyionic liquid (PIL) bearing a hydroxide counter ion. This linear, water-insoluble PIL absorbs 0.20 g·SA /g·polymer, and functions effectively at the near-neutral pHs required of most biocatalysts. As such, the material is sufficiently basic to extract succinic acid during its bioproduction, while also facilitating feed-back control of aqueous solution pH.

GS-2: A Novel Broad-Spectrum Agent for Environmental Microbial Control.

The environmental control of microbial pathogens currently relies on compounds that do not exert long-lasting activity on surfaces, are impaired by soil, and contribute to the growing problem of antimicrobial resistance. This study presents the scientific development and characterization of GS-2, a novel, water-soluble ammonium carboxylate salt of capric acid and L-arginine that demonstrates activity against a range of bacteria (particularly Gram-negative bacteria), fungi, and viruses. In real-world surface testing, GS-2 was more effective than a benzalkonium chloride disinfectant at reducing the bacterial load on common touch-point surfaces in a high-traffic building (average 1.6 vs. 32.6 CFUs recovered from surfaces 90 min after application, respectively). Toxicology testing in rats confirmed GS-2 ingredients were rapidly cleared and posed no toxicities to humans or animals. To enhance the time-kill against Gram-positive bacteria, GS-2 was compounded at a specific ratio with a naturally occurring monoterpenoid, thymol, to produce a water-based antimicrobial solution. This GS-2 with thymol formulation could generate a bactericidal effect after five minutes of exposure and a viricidal effect after 10 min of exposure. Further testing of the GS-2 and thymol combination on glass slides demonstrated that the compound retained bactericidal activity for up to 60 days. Based on these results, GS-2 and GS-2 with thymol represent a novel antimicrobial solution that may have significant utility in the long-term reduction of environmental microbial pathogens in a variety of settings.

Formation of metal carboxylates in diesel fuel by cation metathesis

Fuel filter plugging by metal carboxylates (“soaps”) is a worldwide issue that affects vehicles of all duty cycles. It is a problem that is both systemic in its origins and elusive in its emergence which has made it particularly difficult to ascertain the mechanism of formation. Herein, we report on a method to produce and replicate plugging in a fashion that is reasonably close to conditions that would exist in the field. Metals and bases from oils and salts were tested and this examination thoroughly shows that oil is not a viable source of base or metal regarding metal carboxylate formation in the field. This study does show that certain ordinary salts undergo metathesis with an ammonium carboxylate intermediate already in the fuel to induce plugging in a manner analogous to the mechanism below.

Organic carboxylate salt-enabled alternative synthetic routes for bio-functional cyclic carbonates and aliphatic polycarbonates

A cyclic carbonate with an ammonium carboxylate residue was found to serve as a nucleophile for esterification with alkyl bromides via the SN2 mechanism.

Supramolecular Assembly and Reversible Transition and of Chitosan Fluorescent Micelles by Noncovalent Modulation

Chitosan-based intelligent artificial systems have been of increasing interest for their biocompatibility, multifunctionality, biological activity, and low cost. Herein, we report the fabrication of supramolecular nanoparticles based on water-soluble chitosan (WCS) and 1,1 ′ ,1 ″ ,1 ″ ′ -(ethene-1,1,2,2-tetrayl)tetrakis(benzene-4,1-diyl) tetrakis(azanediyl)tetraacetic acid (TPE-(N-COOH)4), which is capable of reversible transition between polyion complexes (PICs) and hydrogen bonding complexes (HBCs) with tunable aggregation-induced emission driven by pH value. The PIC micelles could be formed via electrostatic interaction between ammonium cations and carboxylate anions under mild alkaline conditions. The formation of the micelles dramatically blocks the nonradiative pathway and enhances the fluorescence of TPE moieties, and the maximum fluorescence intensity was achieved near the isoelectric point due to the restriction of intramolecular motion. In addition, the fluorescence intensity and size of the PIC micelles exhibited a temperature response in the range from 20 to 80°C. Upon adjusting the solution pH to 2, the PIC micelles were reconstructed into hydrogen-bonding complexes while the hydrogen bonding interaction between the protonated carboxyl groups of TPE-(N-COOH)4 and chitosan. Moreover, the size of the micelles underwent a remarkable decrease, whereas the fluorescence emission was further enhanced by ~6.25-fold. The pH actuated micellar transition from PIC to HBC with tunable fluorescence performance is fully reversible. This study provides novel multifunctional materials that are of great importance for their potential application in the fields of optoelectronic devices and chemical and biomedical sensors.

Gold and Silver-Catalyzed Reductive Amination of Aromatic Carboxylic Acids to Benzylic Amines

The reductive amination of benzoic acid and its derivatives would be an effective addition to current synthesis methods for benzylamine. However, with current technology it is very difficult to keep the aromaticity intact when starting from benzoic acid, and salt wastes are often generated in the process. Here, we report a heterogeneous catalytic system for such a reductive amination, requiring solely H2 and NH3 as the reactants. The Ag/TiO2 or Au/TiO2 catalysts can be used multiple times, and very little noble metal is required, only 0.025 mol % Au. The catalysts are bifunctional: the support catalyzes the dehydration of both the ammonium carboxylate to the amide and of the amide to the nitrile, while the sites at the metal-support interface promote the hydrogenation of the in situ generated nitrile. Yields of up to 92% benzylamine were obtained.

Design of Chemoresponsive Soft Matter Using Hydrogen-Bonded Liquid Crystals.

Soft matter that undergoes programmed macroscopic responses to molecular analytes has potential utility in a range of health and safety-related contexts. In this study, we report the design of a nematic liquid crystal (LC) composition that forms through dimerization of carboxylic acids and responds to the presence of vapors of organoamines by undergoing a visually distinct phase transition to an isotropic phase. Specifically, we screened mixtures of two carboxylic acids, 4-butylbenzoic acid and trans-4-pentylcyclohexanecarboxylic acid, and found select compositions that exhibited a nematic phase from 30.6 to 111.7 °C during heating and 110.6 to 3.1 °C during cooling. The metastable nematic phase formed at ambient temperatures was found to be long-lived (>5 days), thus enabling the use of the LC as a chemoresponsive optical material. By comparing experimental infrared (IR) spectra of the LC phase with vibrational frequencies calculated using density functional theory (DFT), we show that it is possible to distinguish between the presence of monomers, homodimers and heterodimers in the mixture, leading us to conclude that a one-to-one heterodimer is the dominant species within this LC composition. Further support for this conclusion is obtained by using differential scanning calorimetry. Exposure of the LC to 12 ppm triethylamine (TEA) triggers a phase transition to an isotropic phase, which we show by IR spectroscopy to be driven by an acid-base reaction, leading to the formation of ammonium carboxylate salts. We characterized the dynamics of the phase transition and found that it proceeds via a characteristic spatiotemporal pathway involving the nucleation, growth, and coalescence of isotropic domains, thus amplifying the atomic-scale acid-base reaction into an information-rich optical output. In contrast to TEA, we determined via both experiment and computation that neither hydrogen bonding donor or acceptor molecules, such as water, dimethyl methylphosphonate, ethylene oxide or formaldehyde, disrupt the heterodimers formed in the LC, hinting that the phase transition (including spatial-temporal characteristics of the pathway) induced in this class of hydrogen bonded LC may offer the basis of a facile and chemically selective way of reporting the presence of volatile amines. This proposal is supported by exploratory experiments in which we show that it is possible to trigger a phase transition in the LC by exposure to volatile amines emitted from rotting fish. Overall, these results provide new principles for the design of chemoresponsive soft matter based on hydrogen bonded LCs that may find use as the basis of low-cost visual indicators of chemical environments.

Synthesis and Characterization of Cationic Dendrimer‐PDMS Hybrids

A modular strategy for the synthesis of dendron-linear polymer hybrids comprised of a flexible polydimethylsiloxane (PDMS) midblock with cationic 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) dendron end groups is developed. The invention of a scalable methodology to access quaternary ammonium carboxylate building blocks and their direct use in esterification chemistry enables rapid access to cationic bis-MPA dendrons. The convergent click coupling of highly charged dendrons to hydrophobic PDMS chain-ends gives a 12-membered family of hybrids that are comprised of different dendron generations (G1-3) and quaternary ammonium alkyl chain lengths (C4 , C8 , C12 , C16 ). This provides a library of materials with variable hydrophobicity, charge density, and chain-end valency. The physical behavior of the dendron-linear PDMS hybrid copolymers significantly changes after introduction of the cationic dendron end-groups and leads to soft-solid materials as a result of inhibited chain mobility. These PDMS-dendron hybrids are expected to behave as surface-active antimicrobial additives in bulk cross-linked silicone systems.

Restorable Neutralization of Poly(acrylic acid) Binders toward Balanced Processing Properties and Cycling Performance for Silicon Anodes in Lithium-Ion Batteries.

Neutralization of poly(acrylic acid) (PAA)-based binders using lithium hydroxide is a common strategy for fabricating silicon anode laminates, which improves rheological properties of slurries toward high-quality electrode laminates. However, the significantly increased basicity causes degradation of Si particles while the irreversible conversion of carboxylic acid groups to lithium carboxylates undermines the binding strength, collectively leading to adverse cycling performance of the fabricated Si anodes. Herein, a novel neutralization process for PAA binders is developed. A weak base, ammonia (NH3), was discovered as a neutralizing agent that still promotes rheological response of binder solutions but results in a reduced pH increase. Interestingly, the resulting ammonium carboxylate groups may cleave during the drying process to restore the neutralized PAA (PAA-NH3) binders to their pristine states. The best-performing composition of 50% neutralization (PAA-50%NH3) provides comparable rheological response as a PAA-Li binder as well as much improved cycling performance. The half-cells using the PAA-50%NH3 binder can deliver 60% capacity retention over 100 cycles at C/3 rate, affording a 23.8% increase compared to PAA-Li half-cells. This restorable neutralization process of PAA binders represents an innovative strategy of mitigating issues from slurry processing of Si particles to achieve concurrent improvements in high-quality lamination and cycling performance.