Acetate Molecules Research Articles

Solvation Structures and Transport Mechanisms of Cations in Water-in-Bisalt Electrolytes for High-Concentration Lithium-Ion Batteries Revealed by Molecular Dynamics Simulations.

The development of safe and cost-effective electrolytes for rechargeable batteries is currently underway. While water-based electrolytes hold promise, their restricted electrochemical stability window poses a challenge. Combining multiple ionic species emerges as a promising strategy to broaden this stability window and optimize Li-ion battery performance. This study focuses on dual-cation electrolytes, which blend lithium and potassium acetates to enhance the electrochemical characteristics of the solution at high concentrations. We investigated the solvation structure of each ion and its interactions on a molecular level. Our analysis reveals that ion clusters and aggregates are formed through shared acetate and water molecules at high salt concentrations. Furthermore, the residence time analyses of atom pairs indicate that cations diffuse in vehicular mode at low concentrations. In contrast, they switch to a structural mode at high concentrations due to diminishing water content. This study offers a comprehensive model for exploring diverse solvation structures of cations and gaining insights into their diffusion mechanisms within water-in-bisalt electrolytes for aqueous Li-ion batteries.

Influence of Selective Carbon 1s Excitation on Auger-Meitner Decay in the ESCA Molecule.

Two-dimensional spectral mapping is used to visualize how resonant Auger-Meitner spectra are influenced by the site of the initial core-electron excitation and the symmetry of the core-excited state in the trifluoroethyl acetate molecule (ESCA). We observe a significant enhancement of electron yield for excitation of the COO 1s → π* and CF3 1s → σ* resonances unlike excitation at resonances involving the CH3 and CH2 sites. The CF3 1s → π* and CF3 1s → σ* resonance spectra are very different from each other, with the latter populating most valence states equally. Two complementary electronic structure calculations for the photoelectron cross section and Auger-Meitner intensity are shown to effectively reproduce the site- and state-selective nature of the resonant enhancement features. The site of the core-electron excitation and the respective final state hole locality increase the sensistivity of the photoelectron signal at specific functional group sites. This showcases resonant Auger-Meitner decay as a potentially powerful tool for selectively probing structural changes at specific functional group sites of polyatomic molecules.

Replacing syngas by formic acid and acetic anhydride with advantages: tandem carbonylation of renewable terpenes and propenylbenzenes

The introduction of aldehyde and acetate functionalities in renewable terpenes and propenylbezenes provides useful feedstocks for fine chemicals, especially in the flavor and fragrance segment. Herein we report the rhodium catalyzed hydroformylation and the tandem hydroformylation/hydrogenation/O-acylation of biomass based propenylbenzenes and terpenes with a mixture of formic acid (FA) and acetic anhydride (Ac2O) as a cheaper and less dangerous alternative for flammable and toxic syngas (carbon monoxide and hydrogen mixture) used in the conventional hydroformylation. In addition, we were able to perform the consecutive aldehyde hydrogenation, followed by O-acetylation, formally adding a methyl acetate molecule in a C-C double bond in a tandem process, which was not feasible with the conventional hydroformylation. For propenylbenzenes containing a phenol moiety, the parallel acetoxylation of this group also took place. The protocol allowed to obtain aldehydes and mono- or diacetate esters, which are potentially valuable as fragrance components.

Combining a Drug and a Nutraceutical: A New Cocrystal of Praziquantel and Curcumin

This study explores the co-crystallization between the drug praziquantel (PZQ) and the nutraceutical curcumin (CU). The investigation revealed two novel solid forms: a cocrystal solvate with ethyl acetate and a non-solvated cocrystal. This novel drug–nutraceutical cocrystal is a praziquantel–curcumin (2:1) cocrystal. The cocrystal solvate has ethyl acetate molecules occupying the voids with minimal interactions within the crystal lattice. The application of heat treatment induces solvent removal and prompts the transition to the non-solvated cocrystal, as highlighted by variable-temperature X-ray powder diffraction (VT-XRPD). Thermal analyses demonstrate the stability of the cocrystal solvate up to approximately 100 °C, beyond which it transforms into the non-solvated phase, which eventually melts at 130 °C.

Investigation of intermolecular interactions in butyl acetate using vibrational spectroscopy and non-empirical calculations

In this work, on the example of butyl acetate, the nature of intermolecular interactions was studied using vibrational spectroscopy (Raman and FTIR) and non-empirical calculations. The geometric structures of the most stable dimer and trimer aggregates of butyl acetate were optimized using the Density Functional Theory (DFT) method based on the B3LYP/6-311++G(d,p) basis set. Molecular aggregations in liquid butyl acetate were shown to be formed by dipole-dipole interactions and weak C-H…O hydrogen bonds. A potential energy distribution (PED) analysis was performed for the butyl acetate molecule, and experimental and calculated frequencies were found to be in good agreement. Frontier molecular orbitals such as the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the butyl acetate molecule were analyzed.

How the spin state tunes the slow magnetic relaxation field dependence in spin crossover cobalt(II) complexes.

A novel family of cobalt(II) compounds with tridentate pyridine-2,6-diiminephenyl type ligands featuring electron-withdrawing substituents of general formula [Co(n-XPhPDI)2](ClO4)2·S [n-XPhPDI = 2,6-bis(N-n-halophenylformimidoyl)pyridine with n = 4 (1-3) and 3 (4); X = I (1), Br (2 and 4) and Cl (3); S = MeCN (1 and 2) and EtOAc (3)] has been synthesised and characterised by single-crystal X-ray diffraction, electron paramagnetic resonance, and static (dc) and dynamic (ac) magnetic measurements combined with theoretical calculations. The structures of 1-4 consist of mononuclear bis(chelating) cobalt(II) complex cations, [CoII(n-XPhPDI)2]2+, perchlorate anions, and acetonitrile (1 and 2) or ethyl acetate (3) molecules of crystallisation. This unique series of mononuclear six-coordinate octahedral cobalt(II) complexes displays both thermally-induced low-spin (LS)/high-spin (HS) transition and field-induced slow magnetic relaxation in both LS and HS states. A complete LS ↔ HS transition occurs for 1 and 2, while it is incomplete for 4, one-third of the complexes being HS at low temperatures. In contrast, 3 remains HS in all the temperature range. 1 and 2 show dual spin relaxation dynamics under the presence of an applied dc magnetic field (Hdc), with the occurrence of faster- (FR) and slower-relaxing (SR) processes at lower (Hdc = 1.0 kOe) and higher fields (Hdc = 2.5 kOe), respectively. On the contrary, 3 and 4 exhibit only SR and FR relaxations, regardless of Hdc. Overall, the distinct field-dependence of the single-molecule magnet (SMM) behaviour along with this family of spin-crossover (SCO) cobalt(II)-n-XPhPDI complexes is dominated by Raman mechanisms and, occasionally, with additional temperature-independent Intra-Kramer [LS or HS (D > 0)] or Quantum Tunneling of Magnetisation mechanisms [HS (D < 0)] also contributing.

Synthesis of carbonyl compounds dibenzo-18- crown-6 by the Grinard reaction

In this article, Grignard reactions of 4´,4´´-diiododibenzo-18- crown-6 were carried out to obtain carbonyl compounds in an inert argon atmosphere. An aldehyde, 4´,4´´-diformyldiioddibenzo-18-crown-6, and a ketone, 4´,4´´-diacetyldibenzo-18-crown-6, were obtained. The reactivity and geometry of ethyl acetate, acetic anhydride, and acetic acid chloride molecules were analyzed, which was reflected in the difference in the yields of the target product: ester (22%) &lt;anhydride (37%) &lt;acid chloride (48%). It was determined that tertiary alcohols and various oxidation products are by-products of the reaction. A quantum-chemical calculation and comparison of the spectra of carbonyl compounds, diacetyldibenzo-18- crown-6 were performed. The obtained compounds were identified using 1H-13C-NMR and IR spectroscopy.

Synthesis, crystal structure and Hirshfeld surface analysis of di-acetato-bis-[4-(2-amino-eth-yl)morpholine]cadmium tetra-hydrate.

The title coordination compound, [Cd(C2H3O2)2(C6H14N2O)2]·4H2O, was synthesized by mixing 2 moles of 4-(2-amino-eth-yl)morpholine and 1 mole of cadmium acetate in double-distilled water. The Cd atom is octa-hedrally coord-inated by two N,N'-bidentate ligands [4-(2-amino-eth-yl)morpholine] and two trans-located acetate mol-ecules. The Cd atom is located on a center of inversion, whereas the 4-(2-amino-eth-yl)morpholine and four water mol-ecules are adjacent to the acetate mol-ecules. The chair conformation of the morpholine mol-ecules is confirmed. In the crystal, adjacent metal complexes and uncoord-inated water mol-ecules are linked via N-H⋯O and O-H⋯O hydrogen-bonding inter-actions, generating R 2 2(6), R 6 6(16), R 6 6(20) and S 1 1(6) motifs and forming a three-dimensional network. A Hirshfeld surface analysis indicated the contributions of various contacts: H⋯H (71.8%), O⋯H/H⋯O (27.1%), and C⋯H/H⋯C (1.0%).

Effect of acetate ions and pH on the morphology of cerium oxide nanoparticles

Cerium oxide nanoparticles (CeNPs) are recognized as functional materials with suitability in diverse applications. Conventional synthesis of CeNPs involves direct addition of alkaline solutions and/or precipitating agents to cerium solutions. Rapid changes in solution concentrations and ligand introduction result in less control over particle size and dispersity. Here, we report a simple hydrothermal synthesis of cubic shaped CeNPs through homogenous precipitation, achieved by introduction of acetate molecules. A distinct trend in CeNPs transitioning from octahedral to cubic morphologies was observed through a series of experiments. Results from experimental and computational studies have demonstrated that acetate plays an important role in directing the morphological transition of CeNPs and providing a pH-buffered environment. The formation of Ce(IV)-acetate complexes not only stabilizes aqueous Ce(IV) but also inhibits its hydrolysis in conditions of lower pH. The stabilization of Ce(IV) ions is also favorably weakened during the hydrothermal treatment, leading to successful homogeneous precipitation and the formation of mono-dispersed cubic-shaped CeNPs.

Computational Study on Piperazine‐1,4‐Diium Acetate Using Dft Investigations: Structural Aspects, Topological and Nonlinear Optical Properties

AbstractThe work aims to investigate the nonlinear optical (NLO) activity of piperazine‐1,4‐diium acetate (PAA) molecule utilizing computational techniques. The computational calculations are performed using density functional theory (DFT) to explore the vibrational modes, electronic and NLO properties of PAA by comparing them with piperazine and acetic acid molecules. The natural bond orbital analysis is performed to identify hydrogen bonding and charge transfer interaction. A vibrational analysis is carried out and the assignment of fundamental modes is done using the vibrational energy distribution analysis (VEDA) program. Molecular electrostatic potential, frontier molecular orbital, electron localization function, localized orbital locator and Fukui analysis are carried out to identify chemical reactivity and charge transfer interaction. The UV–visible analysis is performed to obtain the electronic absorption spectrum. The hole–electron analysis is performed for the first five excitations to identify the type of excitation. The atoms in molecules, reduced density gradient and independent gradient model are performed to identify the hydrogen bonding, steric and van der Waals interactions. Hirshfeld analysis is performed to explore the intermolecular interactions within the PAA molecule. The NLO calculation is performed to evaluate the NLO parameters. The obtained results show that the PAA molecule is suitable for NLO applications.

Combination of peracetic acid dosing with diffused aeration in municipal wastewater treatment.

Wastewater aeration is an important unit operation that provides dissolved oxygen for microorganisms in wastewater treatment. In this study, the impact of peracetic acid (PAA) dosing on wastewater aeration was assessed in terms of oxygen transfer, visual observation of bubble size changes, and evolution of dissolved oxygen from PAA (and H2O2) decomposition. Oxygen transfer coefficients improved with PAA concentrations of up to 7 mg/L, which was probably due to the smaller bubbles being formed from the aeration diffuser and evolution of small bubbles from PAA (and H2O2) decomposition. At a PAA concentration higher than 7 mg/L, the accumulation of acetate molecules to the gas-liquid interface of bubbles likely began to counteract the positive impact of bubble size decrease by increasing the mass transfer resistance of oxygen from bubbles to water. Finally, a continuous bench-scale primary effluent aeration experiment demonstrated that at a continuous PAA dosing of 1 mg/L, the air input by a compressor could be decreased by 54%, while keeping the oxygen level constant at approximately 1.5 mg/L. PAA dosing could be combined, for example, with aerated grit removal to enhance the primary effluent aeration together with additional benefits of partial disinfection and odor formation prevention.

Simultaneous degradation of microplastics and sludge during wet air oxidation

Microplastics (MPs) generated from daily life are commonly collected by urban sewage pipe networks and then transfer to sludge in wastewater treatment plants. Conventional biochemical treatment processes cannot degrade MPs effectively, causing an ecological risk via sludge land use. Wet air oxidation (WAO) is a promising sludge treatment technology with a strong ability to decompose complex organic matter, but its potential for the removal of MPs in sludge was unclear. In this study, three common MPs (polyethylene, polystyrene, and polyethylene terephthalate, which are called PEMPs, PSMPs, and PETMPs) were added into the sludge samples (1 g MP in 180 mL sludge), to test the effects of WAO on sludge and MPs. The results showed that WAO simultaneously degraded sludge and the PEMPs, and the two degradation processes were relatively independent when oxygen was supplied adequately. The dissolution of PSMPs and organic matter in sludge was not affected by each other, but the degradation rate was slowed down due to the interaction of ketones and benzene compounds. The hydrolysis of sludge and PETMPs was accelerated, while the hydrolyzed products such as terephthalic acid were oxidized without interfering with each other. No obvious MPs remained in the effluent, and volatile fatty acids (VFAs) were the main components, among which acetic acid accounted for 90%. When the sludge was treated with PEMPs, PSMPs, or PETMPs, the concentration of acetic acid finally accounted for 45%, 21%, and 18% of DOC. Overall, MPs can be degraded or even mineralized during sludge WAO, and humic acid derivatives, acetate, and other small molecules of alcohols, ketones, or aldehydes were the typical intermediates.

PH-Dependent Binding and Releasing Mechanism of Acetate in the Inner Water Cavity of Heliorhodopsin.

The high-resolution structure of heliorhodopsin crystallized at low pH reveals the presence of a planar triangle molecule, acetate, in the inner water cavity. Here, we investigate how the acetate molecule is stabilized at the counterion Glu107 moiety, using molecular dynamics (MD) simulations and a quantum mechanical/molecular mechanical (QM/MM) approach. QM/MM calculations indicate that the density is best described as acetate among triangle acids, including nitric acid and bicarbonate. The calculated protonation state indicates that protonated acetate donates an H-bond to deprotonated Glu107 in the low-pH crystal structure. The observed red-shift of ∼30 nm in the absorption wavelength with pKa ≈ 4 is likely due to the His23/His80 protonation, rather than the Glu107 protonation. MD simulations also show that acetate can exist at the Glu107 moiety only when it is protonated. When ionized, acetate is released from the Glu107 moiety via Asn101 at the channel bottleneck and Arg91 on the intracellular protein surface. These observations could explain how acetate binds at low pH and releases at high pH.

Preparation and Characterization of Porous Cellulose Acetate Nanofiber Hydrogels.

The currently reported methods for preparing cellulose acetate hydrogels use chemical reagents as cross-linking agents, and the prepared ones are non-porous structured cellulose acetate hydrogels. Nonporous cellulose acetate hydrogels limit the range of applications, such as limiting cell attachment and nutrient delivery in tissue engineering. This research creatively proposed a facile method to prepare cellulose acetate hydrogels with porous structures. Water was added to the cellulose acetate-acetone solution as an anti-solvent to induce the phase separation of the cellulose acetate-acetone solution to obtain a physical gel with a network structure, where the cellulose acetate molecules undergo re-arrangement during the replacement of acetone by water to obtain hydrogels. The SEM and BET test results showed that the hydrogels are relatively porous. The maximum pore size of the cellulose acetate hydrogel is 380 nm, and the specific surface area reaches 62 m2/g. The porosity of the hydrogel is significantly higher than that of the cellulose acetate hydrogel reported in the previous literature. The XRD results show that the nanofibrous morphology of cellulose acetate hydrogels is caused by the deacetylation reaction of cellulose acetate.

Stabilization of Component-Pure α-FAPbI3 via Volatile Additives for Stable Photovoltaics

State-of-the-art high-performance perovskite solar cells are mainly based on formamidinium (FA)-dominated perovskites because of their narrow band gap and remarkable thermal resistance. However, photoactive α-FAPbI3 is prone to transit to the photoinactive phase, and pioneering phase stabilization strategies can induce undesirable band gap broadening or phase segregation, seriously restricting the efficiency and long-term stability of the resultant photovoltaics. Herein, a small molecule of ammonium acetate (NH4Ac) was introduced as an additive in a modified ripening method to fabricate component-pure α-FAPbI3. Owing to the strong interaction between NH4Ac and PbI2, FAI via Pb-O coordination, and N-H···N hydrogen bonding, vertically oriented perovskites with relaxed crystal strain were first generated, which were fully converted to α-FAPbI3 in a further ripening process. The NH4Ac was fully volatized after the perovskite formation, resulting in component-pure α-FAPbI3 with a band gap of 1.48 eV and remarkable stability under light illumination. Ultimately, a champion device efficiency of above 21% was obtained based on the component-pure α-FAPbI3 and over 95% of the initial efficiency can be maintained after 1000 h of aging.

The Perspective of Using the System Ethanol-Ethyl Acetate in a Liquid Organic Hydrogen Carrier (LOHC) Cycle

Starting from bioethanol it is possible, by using an appropriate catalyst, to produce ethyl acetate in a single reaction step and pure hydrogen as a by-product. Two molecules of hydrogen can be obtained for each molecule of ethyl acetate produced. The mentioned reaction is reversible, therefore, it is possible to hydrogenate ethyl acetate to reobtain ethanol, so closing the chemical cycle of a Liquid Organic Hydrogen Carrier (LOHC) process. In other words, bioethanol can be conveniently used as a hydrogen carrier. Many papers have been published in the literature dealing with both the ethanol dehydrogenation and the ethyl acetate hydrogenation to ethanol so demonstrating the feasibility of this process. In this review all the aspects of the entire LOHC cycle are considered and discussed. We examined in particular: the most convenient catalysts for the two main reactions, the best operative conditions, the kinetics of all the reactions involved in the process, the scaling up of both ethanol dehydrogenation and ethyl acetate hydrogenation from the laboratory to industrial plant, the techno-economic aspects of the process and the perspective for improvements. In particular, the use of bioethanol in a LOHC process has three main advantages: (1) the hydrogen carrier is a renewable resource; (2) ethanol and ethyl acetate are both green products benign for both the environment and human safety; (3) the processes of hydrogenation and dehydrogenation occur in relatively mild operative conditions of temperature and pressure and with high energetic efficiency. The main disadvantage with respect to other more conventional LOHC systems is the relatively low hydrogen storage density.

Recyclable Co3O4/NaF for hydrogen generation from ethyl acetate: The promoting effect between Co3O4 and NaF

Secondary reforming of oxygenated organic compounds is the key to opening up the industrial chain of hydrogen production from organic matter. In this work, a low-cost and high-efficiency Co3O4/NaF catalyst with recyclable re-preparation was developed to solve the application bottleneck that existing commercial reforming catalysts were expensive and difficult to recycle after deactivation and discarded. Ethyl acetate was selected as the representative oxygenated organic compound for hydrogen generation via autothermal reforming was studied. The results showed that the Co3O4/NaF catalysts efficiently produced hydrogen from ethyl acetate, and the 7.5 %-Co3O4/NaF catalyst achieved 82.7 % hydrogen yield at 600 °C, 100 % ethyl acetate conversion and 16 h running stability. And the used catalyst after once recyclable re-preparation is restored to the initial hydrogen production level of fresh catalyst. Combined with XRD, N2 adsorption/desorption, FE-SEM, H2-TPR and in situ DRIFTS analysis, it was found that the surface micro-structure of the Co3O4/NaF catalyst was dense, and its specific surface area was ultra-small less than 0.5 m2·g−1, which broke through the limitation that low specific surface catalyst was difficult to obtain high-mass catalytic activity. The hydrogen production from ethyl acetate via autothermal reforming over the Co3O4/NaF catalyst was a rapid surface reaction. In addition, DFT calculations confirmed that NaF could effectively adsorb ethyl acetate molecule with an adsorption energy of −0.438 eV/molecule, and the combination of Co3O4 and NaF promoted more efficient adsorption of ethyl acetate molecules by Co3O4/NaF, with an adsorption energy of −0.836 eV/molecule. The F atom in NaF can induce electrons migration from the Co atom in Co3O4 to the F atom, which improved the redox properties and hydrogen production activity of the Co3O4/NaF catalyst.

Regulation of alanine racemase activity by carboxylates and the d-type substrate d-alanine.

Alanine racemases (ALRs) are essential for d-alanine (d-Ala) production in bacteria, and many ALRs have a conserved carbamylated lysine residue in the active site. Although short-chain carboxylates inhibit ALRs harbouring this lysine residue as substrate analogues, in an ALR variant with an alanine residue at this position, carboxylates behave as activators; however, this activation mechanism remains unclear. Here, we performed kinetic and structural analyses of U1ALR, an ALR from Latilactobacillus sakei UONUMA harbouring a glycine residue (Gly134) in the site of the carbamylated lysine residue. U1ALR was activated by various carboxylates and also by a G134K mutation, both of which caused a significant decrease in Km , indicating an increase in substrate affinity. The U1ALR crystal structure revealed the presence of an acetate molecule bound in a position and at an orientation resembling the conformation of the carbamylated lysine side chain observed in the structures of other ALRs. These results suggest a regulatory mechanism for U1ALR activity involving two carboxylate-binding sites: one with high affinity near Gly134, where an acetate molecule is observed in the crystal structure and carboxylate binding results in enzyme activation; the other is the substrate-binding site, where carboxylate binding inhibits enzyme activity. Furthermore, we observed no carboxylate/G134K-mediated activation in the presence of d-Ala at high concentrations, implying that d-Ala also exhibits low-affinity binding in the first carboxylate-binding site and prevents carboxylate/G134K-induced activation. Such regulation of enzyme activity by carboxylates and d-Ala may be ubiquitous in many ALRs from lactic acid bacteria sharing the same sequence characteristics.

Highly Efficient Flexible Perovskite Solar Cells through Pentylammonium Acetate Modification with Certified Efficiency of 23.35.

Among the emerging photovoltaic technologies, rigid perovskite solar cells (PSCs) have made tremendous development owing to their exceptional power conversion efficiency (PCE) of up to25.7%. However, the record PCE of flexible PSCs (≈22.4%) still lags far behind their rigid counterparts and their mechanical stabilities are also not satisfactory. Herein, through modifying the interface between perovskite and hole transport layer via pentylammonium acetate (PenAAc) molecule a highly efficient and stable flexible inverted PSC is reported. Through synthetic manipulation of anion and cation, it is shown that the PenA+ and Ac- have strong chemical binding with both acceptor and donor defects of surface-terminating ends on perovskite films. The PenAAc-modified flexible PSCs achieve a record PCE of23.68% (0.08 cm2 , certified: 23.35%) with a high open-circuit voltage (VOC ) of1.17V. Large-area devices (1.0 cm2 ) also realized an exceptional PCE of21.52%. Moreover, the fabricated devices show excellent stability under mechanical bending, with PCE remaining above91% of the original PCE even after5000 bends.

An Intermolecular interaction in binary liquid mixture of Ethyl Aceto Acetate with o, m, p - Xylene: An Volumetric and Viscometric study

The density and viscosity in binary mixture of Ethyl Aceto Acetate with o, m, p - xylene have been measured over the whole composition range at 303.15K. From these data some of excess viscosity and excess molar volume of o, m, p - xylene in Ethyl Aceto Acetate were calculated using the value of density and viscosity. The results are interpreted in term of molecular interaction between the components of the mixture. It has been observed that molecular interaction existing in the system is highly disturbed by the polar Ethyl Aceto Acetate molecule and depressive type interaction are existing in the system