Formation Of Hydronium Ion Research Articles

Science in a cup of coffee: A structural study of a trigonelline aqueous solution

Bioactive trigonelline is one of the important components of coffee, contributing to its characteristic undue bitterness. In this report we looked at the structure of an aqueous solution of trigonelline by means of Neutron Diffraction with Isotopic Substitution (NDIS). This experimental approach has been coupled with a Monte Carlo simulation to get an atom-level description of the solution. The rationale behind the present study is to investigate the solvent-solute and the solute-solute interactions; these have implications relevant also to other bioactive molecules and, in addition, can provide basic information on the extraction efficiency and on the solubility of important molecules in coffee. Results indicate a limited short-ranged involvement of the solute trigonelline with the water solvent and a not negligible clustering of trigonelline molecules. The investigated solution contains both positively charged and zwitterionic trigonelline, along with Cl− and H+, with this latter ion involved in hydronium ion formation. Here it is found that the observed structures are compatible with a Zundel-like cation, thus contributing to the still on-going debate on the presence of either Zundel or Eigen complexes in acidic solution. The role of a Zundel-like cation, along with its interaction with the chloride ion, might be related to the extraction and solubility of important molecules in coffee, in order to define the best water composition resulting in the best coffee.

A microfluidic proton flow reactor system: In-situ visualisation of hydrogen evolution and storage in carbon-based slurry electrodes

A Proton flow reactor (PFR) system stores energy in the form of hydrogen in porous carbon particles in slurry electrodes. However, the hydrogen storage mechanisms and the reactions in this system are not well understood. In this study, we design and fabricate a microfluidic proton flow reactor (MPFR) as a small-scale PFR to enable in-situ visualisation of the key processes underlying PFR operations. We observe the behaviour of slurries and water in both hydrogen and oxygen sides with emphasis on processes in the vicinity of membranes. We use fluorescence microscopy with quinine to visualize hydronium transport from the oxygen to the hydrogen side and employ in-situ Raman spectroscopy to analyze surface structural changes in carbon particles before and after charging. Fluorescence microscopy demonstrates the formation of hydronium ions on the oxygen side and their subsequent migration to the hydrogen side, proving that the oxygen evolution reaction occurs on the oxygen side. Raman heat maps prove the formation of carbon–hydrogen bonding in particles after they are charged with PFR. Although the MPFR is operated at non-optimal slurry concentrations to allow optical access, we demonstrate that it provides maximum hydrogen storage capacity of 0.64 wt%.

Reduced graphite oxide-pure water supercapacitor: A futuristic water based energy storage device

With the ever-increasing use of supercapcitors, there is a need for exploring more environment friendly active material-electrolyte combinations. Herein, we report an environmentally benign supercapacitor employing reduced graphite oxide obtained by hydrazine reduction of graphite oxide as active material and pure water (HPLC grade) as ‘electrolyte’. We could achieve a specific capacitance of 333 Fg -1 at a galvanostatic charge-discharge current of 0.3 Ag -1 . Maximum energy and power density values are 29.6 Whrkg −1 and 266.2 Wkg -1 respectively. Energy storage mechanism is the diffusion of hydronium ions within the interlayer region of the active material. Hydronium ions are produced by the hydrolysis of hydroxyl groups at the active material - water interface. This supercapacitor exhibits good cycle stability. Concentration of hydroxyl groups is found to be crucial in determining the electrochemical performance. This supercapacitor is thermally self-chargeable with a thermoelectric coefficient of 4.07 mV°C −1 which makes it even more futuristic and environment friendly. • Novel supercapacitor using pure water as electrolyte. • Storage of electrical energy at reduced-graphite oxide-water interface. • Hydrolysis of hydroxyl groups lead to formation of hydronium ions. • Storage mechanism is the diffusion of hydronium ions within the interlayer region of the active material. • Supercapacitor is thermally self-chargeable.

Proton Transfer Reaction in Water: Hydronium Ion Formation

The current ongoing scientific debate deals with accumulation of hydronium ions (H3O+) on water surface. Elevated interfacial concentration measured by using Raman spectroscopy. A strong surface affinity of H3O+ indicated by Raman spectroscopy under similar conditions. Ion adsorption phenomena, H3O+ formation and its structural activity emphasized in our study. Asymmetric water ion adsorption clearly observed in our research.

Perfluorosulfonyl Imide versus Perfluorosulfonic Acid Ionomers in Proton-Exchange Membrane Fuel Cells at Low Relative Humidity.

Designing highly conductive ionomers at high temperature and low relative humidity is challenging in proton-exchange membrane fuel cells. Perfluorosulfonyl imide ionomers were believed to achieve this goal, owing to their exceptional acidity and excellent thermal stability. Perfluorosulfonyl imide ionomers are less conductive than the analogous perfluorosulfonic acids despite similar membrane microstructure. In this study, the distinct behavior is rationalized by in situ synchrotron infrared spectroscopy during hydration. The protonation mechanism, formation of the protonic moiety and water clustering are totally different for the two different families of membranes. The ionization mediated by trans-to-cis conformational transition of the perfluorosulfonyl imide ionomer is not accompanied by the formation of hydronium ions. In contrast, Zundel-ion entities were identified as the elementary protonic complex, which is stable over the hydration range. The H-bond network of surrounding water molecules appears to be less connected and the protons remain highly localized and unavailable for efficient structural transport. The delocalization of protons and their mitigated interaction with the surrounding medium are prominent effects that negatively impact conductivity.

Effect of hydration and structure on the fragmentation of 2,2-(propane-1,3-diyl)bis(isoindoline-1,3-dione) and 2,2-(ethane-1,2-diyl)bis(isoindoline-1,3-dione) in electron impact ionization-mass spectrometry: A theoretical and experimental study

Two bis-phthalimide derivatives, 2,2-(ethane-1,2-diyl)bis(isoindoline-1,3-dione) (3) and 2,2-(propane-1,3-diyl)bis(isoindoline-1,3-dione) (4) were synthesized and characterized by 1H NMR, 13C NMR and electron impact ionization-mass spectrometry (EI-MS). Effect of the alkyl length on the fragmentation of the compounds 3 and 4 was investigated and it was found that molecular ion of 3 with a CH2–CH2 group is almost completely decomposed, so that a small peak was observed for its molecular ion at m/z of 320. On the other hand, an intense peak with m/z of 334 was observed for the molecular ion of 4 indicating the stability of 4+ ion. The results were interpreted using computational method at B3LYP/6-31 + G(d) level of theory. Also, comparison of the mass spectra showed that the cation 4+ is tri-hydrated while 3+ is not hydrated. From the optimized structures of 4+(H2O)1-3 clusters, it was found that the extra stability of 4+(H2O)3 is due to formation of hydronium ion (H2O)2H3O+.

Degradation kinetic study of cholesterol lowering statin drug using sono-hybrid techniques initiated by metal-free polymeric catalyst

Abstract The present study addressed the degradation kinetics of cholesterol lowering statin drug using metal-free polymeric catalyst g-C3N4 synthesized through sonochemical method followed by thermal condensation. The photocatalytic experiments were performed to assess the catalytic activity of the synthesized g-C3N4 catalyst. The results revealed that the g-C3N4 possesses high oxidation properties and able to degrade ∼93% of lovastatin within a short span of time 10 min under sono-hybrid technique with a rate constant of 15.1 × 10–2 min–1. On the other hand, the maximum synergy index was attained when the ultrasound was applied with g-C3N4 nanoparticles. A significant enhancement of 2.25 folds higher degradation efficiency was achieved as compared to the sonolysis process alone. This enhancement is due to the addition of catalyst which facilitates more nucleation sites for cavitation bubbles and promoted cavitation phenomenon in the system. The study of adsorption and oxidation processes revealed that the degradation of lovastatin was primarily by oxidation reaction. When the experiments were performed at low pH, a significant degradation was observed – which is due to the formation of hydronium ions (H3O+). This H3O+ produces alternative and reactive species such as •OH, •O, HO 2 • in the presence of free electrons in the reaction solution. The maximum synergy was seen for (US+g-C3N4) process followed by (US+g-C3N4+H2O2+UVC) and (US+UVC). The experimental results of stability and reusability of the catalyst also confirmed that the catalyst could be easily regenerated and reused for several times without losing any catalytic activity – which might be useful for reducing the total operating cost for a wastewater treatment plant.

Bonding, structural and thermodynamic analysis of dissociative adsorption of H3O+ ion onto calcite (101⁻4) surface: CPMD and DFT calculations.

We used density functional theory (DFT) and Car-Parrinello molecular dynamics (CPMD) simulation to investigate the adsorption and bond formation of hydronium ion (H3O+) onto a [Formula: see text] calcite surface. For surface coverage of 25% to 100%, the nature of H3O+ interaction was explored through electron density and energetics in the context of bond critical points. The adsorbate-adsorbent structure was studied by simulation ofpair correlation function. The results revealed that dissociation into water molecule(s) and proton(s) complements H3O+ ion(s) adsorbtion. The H2O molecule adsorbs onto the surface via its O atom, and interacts with surface calcium in a closed-shell mode; the H+ ion makes a covalent bond to the surface oxygen while maintaining H-bonding with water. Adsorption energies were diminished by 70-90kJmol-1 when Obridge-bonded H+ ions transferred to the Oterminal manually. While dissociative adsorption of H3O+ ions is spontaneous at all surface coverages tested, the free energy was lowest at 75% coverage. Also, protonation of a completely pre-hydrated calcite surface leads to stronger interaction of water molecules with the surface. This unique outlook on hydrating calcite provides specific insights into biomineralization of this mineral, and helps depict further pH consequences in the field of biomaterial adsorption. Graphical abstract Dissociative adsorption of hydronium ion onto the surface of calcite.

Ab initio calculation of hydration and proton transfer on sulfonated nata de coco

The repeating unit of sulfonated “ nata de coco” is D-glucose sulfonate. This research aims to determine the most stable structures of sulfonated nata de coco polymer membrane, the energy and hydrogen bonds, in order to understand the characteristics, local hydration, and proton transfer on the membrane on the ab initio electronic structure calculation. The minimum energy structure for its monomer (two, three, four and five) are calculated by B3LYP/6-311G (d) method. The calculations show that there is no significant energy change on the structure interaction of two, three, four and five monomer of sulfonated nata de coco with one water molecule, which is about -18.82 kcal/mole. Those calculations that two monomers form of sulfonated nata de coco might be used to further calculation and research, because it can be considered as the representative for their polymer. The optimization and B3LYP/6-311G (d) calculation shows the amount of water molecule used for proton transfer is closely related to the formation of hydrogen bonding with sulfonic group. By the addition of one or two water molecule, the dissociated proton is stabilized by formation of hydronium ion. For further addition of water molecule (three to ten water molecules), the proton dissociation is also stabilized by the formation of Zundel ion and Eigen ion. The calculation of interaction energy with n water molecule ( n = 1-10) shows that both energy change ( ∆E ), and enthalpy change ( ∆H ) are more negative. This implies that the interaction with water molecule is stronger. The bonding energy is about 14.0-16.5 kcal/mole per water molecule. On the addition of four and eight water molecules, proton dissociation forms two Zundel ion and two Eigen ions and causes lower bonding energy about 2 kcal/mole. Those optimization and energy calculations conclude that the formation of hydrogen bonding among water molecule and sulfonic group affects proton transfer on sulfonated nata de coco membrane.

Acceleration of Acid-Catalyzed Hydrolysis in a Biphasic System by Sodium Tetracyanocyclopentadienides.

The hydrolysis of tert-butyldimethylsilyl L-menthyl ether (3) in a CH2Cl2-1 M HCl biphasic solvent system was accelerated by the addition of sodium tetracyanocyclopentadienides 1. Particularly, the reaction rate was enhanced using sodium salt 1a-c with a lipophilic substituent on the cyclopentadienide ring. From the results obtained by a triphasic experiment, hydrolysis proceeds via the formation of hydronium ion 2 in the aqueous phase by ion exchange, followed by the transfer of 2 to the CH2Cl2 phase.

Polypyrrole Microwires as Toxic Gas Sensors for Ammonia and Hydrogen Sulphide

Polypyrrole (PPy) microwires synthesized via template assisted chemical polymerization method were investigated as gas sensors for ammonia (NH3) and hydrogen sulphide (H2S) toxic gases. The sensor was fabricated by a facile technique in which polypyrrole microwires were packed between a pair of indium tin oxide (ITO) coated glass slides acting as electrodes. Electrical conductivity of sensor, containing polypyrrole microwires, was examined with the exposure of the toxic gases at room temperature. It was observed that microwires detect the presence of toxic gases in terms of change in electrical conductivity. These microwires can be used as selective toxic gas sensor because conductivity decreases in the presence of NH3 gas and increases in the case of H2S gas. In both the cases, the change in conductivity was found to be reversible and a drift in recovery from the original value of electrical resistance (conductivity) was also observed on the removal of toxic gas environment. This happens as a consequence of the formation of hydronium ion because of the moisture present in the ambient air.

Effect of microhydration on dissociation of trifluoroacetic acid.

First-principle-based electronic structure calculations were carried out on microhydrated trifluoroacetic acid clusters (CF3COOH, tfa) to understand its molecular level interaction with water and subsequent ionic dissociation to form CF3COO(-) ion. From several geometrical inputs, the global minimum energy structure of hydrated cluster, tfa · nH2O (n = 1-7), was obtained adopting dispersion-corrected density functional, namely, ωB97X-D, and a set of correlated atomic basis function, aug-cc-pVDZ. It was predicted that tfa requires at least six H2O molecules to dissociate. Energy parameters of these hydrated clusters were improved by applying MP2 as well as CCSD(T) methods. A linear variation was observed for calculated solvent stabilization energy profile with the number of solvent H2O molecules present in the hydrated cluster. However, the calculated interaction energy profile showed the characteristic feature indicating the formation of contact ion-pair on the addition of six H2O molecules to tfa. On the basis of energy decomposition analysis, it was observed that the major interaction between tfa and H2O molecules was of electrostatic nature. On successive addition of water molecules, the electrostatic component of the interaction between solute and solvent molecules depicted a sudden increase when moving from penta- to hexahydrated cluster. This observed nature of energy profile coincided with the formation of hydronium ion in the case of hexahydrated cluster. The formation of H3O(+) was manifested in simulated IR spectra of tfa·6H2O and tfa · 7H2O clusters. A large red shift in IR peak positions corresponding to O-H stretching of tfa was predicted on microhydration.

Mechanochemical Wear of Soda Lime Silica Glass in Humid Environments

The mechanochemical wear of multicomponent glasses was studied under controlled humidity conditions using a reciprocating ball‐on‐flat tribometer. For dry conditions, the surfaces were extensively damaged by scratching for all of the glasses, while for humid conditions the wear behavior varied with the glass composition suggesting a chemical effect on scratch behaviors of glass surfaces. The wear of soda lime silica (also called sodium calcium silicate) glass was suppressed with increasing humidity, while the borosilicate and barium boroaluminosilicate glasses showed an increase in wear volume with increasing humidity. The unique humidity dependence of the observed mechanochemical wear of soda lime silica glass supports the hypothesis that hydronium ion formation in the sodium‐leached sites of the soda lime glass enhances its wear resistance.

Dissociative Chemisorption of Water onto Silica Surfaces and Formation of Hydronium Ions

Dissociative Chemisorption of Water onto Silica Surfaces and Formation of Hydronium Ions

Molecular Dynamics Simulations of the Structure of Nanoconfined Water in Porous Silica and Enhanced Hydronium Ion Formation

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Dissociative Chemisorption of Water onto Silica Surfaces and Formation of Hydronium Ions

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionDissociative Chemisorption of Water onto Silica Surfaces and Formation of Hydronium Ions and S. H. GarofaliniCite this: J. Phys. Chem. C 2008, 112, 14, 5694Publication Date (Web):March 13, 2008Publication History Published online13 March 2008Published inissue 1 April 2008https://doi.org/10.1021/jp8015134Copyright © 2008 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views424Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (5 KB) Get e-Alerts Get e-Alerts

Dissociative Chemisorption of Water onto Silica Surfaces and Formation of Hydronium Ions

Molecular dynamics (MD) computer simulation of the adsorption of water molecules onto the vitreous silica surface was performed using a new dissociative water potential.58 The simulations showed dissociative chemisorption of water molecules onto the silica surface, forming silanol (SiOH) groups at a concentration consistent with experimental data. Water penetration and silanol formation ∼7−8 Å below the outermost oxygen are observed. Because of the dissociative nature of the water potential, formation of hydronium ions is allowed, and, whereas seldom observed in the simulations of bulk water, hydronium ions are formed during the reactions causing the formation of the silanols. The formation of hydronium ions has also been observed in ab initio calculations of water adsorption onto silica surfaces. The time evolution of the reactions involving hydronium ions in our MD simulations is similar to that observed in first-principles MD calculations. Hydronium ions offer a mechanism by which initially singly coordinated terminal oxygen (Si−O-) receives a H+ ion from a relatively distant chemisorbed H2O molecule via multiple H+ ion transfer, creating two SiOH sites.

Spectroscopic Probes of the Quasi-Liquid Layer on Ice

Raman spectra of the water OH-stretch region were acquired at air-ice and air-water interfaces at a glancing angle, which allowed observation of surface characteristics. The shapes of the OH-stretch bands indicate that the environment at the air-ice interface is different from that at the air-water interface and from that seen in bulk water. Water spectra measured at the surface of dodecane under low relative humidity indicate that this method is sensitive to fewer than 50 monolayers of water. Changes in the local environment of the surfacial water molecules may be induced by the presence of different solute species, giving rise to changes in the shape of the band. Dissolved sodium chloride disrupts hydrogen bonding in liquid water and has the same effect at the air-ice interface. However, when either HCl or HNO(3) is adsorbed from the gas phase onto an ice surface, the opposite effect is seen: Their presence appears to increase the extent of hydrogen bonding at the ice surface. At the same time, shifts in the laser-induced fluorescence spectra of acridine, a fluorescent pH-probe present at the air-ice interface, indicate that dissociation of acids occurs there. These observations suggest that the formation of hydronium ions at the air-ice interface enhances the hydrogen bonding of surfacial water molecules.

Hydronium ion formation during the hydrometallurgical formation of valentinite (Sb2O3)

Hydronium ion formation during the hydrometallurgical formation of valentinite (Sb₂O₃)

Thermodynamics of Nafion™–vapor interactions. I. Water vapor

Interaction between water vapor and Nafion™ perfluorosulfonate ionomer has been investigated via combined flow microcalorimetry and isothermal sorption over a wide range of water relative pressure. The molar enthalpy of sorption was determined for the untreated polymer, the residual polymer after extraction by aqueous propanol, and the extracted fraction. The extract appears to be low molecular weight Nafion™ but with an equivalent weight more than double that of the unextracted polymer. The equivalent weight of the residual polymer is slightly lower than that of the original Nafion™, apparently due to partial alkylation. Molar enthalpy for formation of the sulfonic acid monohydrate is about the same for the residual and unextracted polymers, but much greater for the extracted fraction. For untreated Nafion™, the magnitude and concentration dependence of the molar enthalpy indicates that sorption of water exhibits a clear progression from hydronium ion formation (≤1 H 2O/SO 3H) through growth of isolated hydrated clusters (≤6 H 2O/SO 3H) to a continuous internal water phase. A more complicated process occurs for the extract and residual polymer fractions in that an endotherm associated with elastic compression of the polymer matrix surrounding isolated water clusters is superimposed on the hydration exotherm over the concentration range of cluster growth. There is only a minor indication of this endotherm for unextracted Nafion™ because of more facile relaxation of the polymer structure due to plasticization by the low molecular weight fraction.