HCl Molecules Research Articles

Development of phase-change absorbent for hydrogen chloride with hydrogen and chlorine generation by electrolysis

To reduce the energy consumption of regeneration for HCl absorption, and to recover HCl to high-value products, a sustainable phase-change system was constructed with N-methyldiethanolamine (MDEA) and polyethylene glycol dimethyl ether (NHD) in this paper. The MDEA/NHD phase change absorbent for HCl absorption is optimized by the ternary phase diagram and phase behavior of MDEA/NHD/HCl system. The results demonstrate that the biphasic system can be constructed with the mass fraction of HCl less than 28% and NHD component in the range of 23.0% ∼ 95.3%. Because of the higher stability of protonated MDEA·HCl than that of NHD·HCl, HCl molecules are mainly enriched in MDEA phase containing the volume ratio of less than 1/3 and partition coefficient over 100 at the neutral point. Therefore, only MDEA phase needs to be recycled, which results in reducing the circulation of regeneration by approximately 68%. Moreover, concentrated HCl in anhydrous MDEA phase could further prevent the side reaction of OER and improve the Faradaic efficiency toward HER and CER to reach 98.5% and 90.5% at 55 °C, respectively. And the energy consumption of regeneration is reduced to 0.37 GJ/t(absorbed HCl) in MDEA/NHD biphasic absorbent compared with that of 2.3 GJ/tCO2 by DMX™ phase change absorption for CO2. By enhancing the conductivity and decreasing the viscosity of MDEA phase, introducing water in MDEA/NHD/HCl solution within 5% could significantly promote the current density and maintain high Faradaic efficiency toward HER and CER as 89.0% and 86.8%, respectively. Therefore, it is a promising technology to be applied in industry.

Plasma Parameters and Kinetics of Reactive Ion Etching of SiO2 and Si3N4 in an HBr/Cl2/Ar Mixture

The parameters of the gas phase and the kinetics of reactive ion etching of SiO2 and Si3N4 under conditions of an induction RF (13.56 MHz) discharge with a varying HBr/Cl2 ratio is studied. The study includes plasma diagnostics using Langmuir probes, plasma modeling to find stationary concentrations of active particles, measuring velocities, and analyzing etching mechanisms in the effective interaction prob-ability approximation. It is found that the substitution of HBr by Cl2 at a constant argon content (a) is accompanied by a noticeable change in the electrical parameters of the plasma; (b) leads to a weak increase in the intensity of ion bombardment of the treated surface; and (c) causes a significant increase in the total concentration and flux density of reactive particles. It is shown that the etching rates of SiO2 and Si3N4 increase monotonically as the proportion of Cl2 increases in a mixture, while the main etching mechanism is an ion-stimulated chemical reaction. The model description of the kinetics of such a reaction in the first approximation assumes (a) the additive contribution of bromine and chlorine atoms and (b) the direct pro-portional dependence of their effective interaction probabilities on the intensity of ion bombardment. The existence of an additional channel of heterogeneous interaction with the participation of HCl molecules is proposed.

Construction of Highly Dispersed Cu–P/Cl Active Sites Using Methyldiphenyloxophosphine for Efficient Acetylene Hydrochlorination

To overcome the disadvantages of Cu-based catalysts, such as the low dispersion of active components and insufficient active species, several 15% Cu-Lx/AC catalysts for acetylene hydrochlorination were synthesized based on strong interactions between a ligand and CuCl2 precursors. The introduction of the methyldiphenyloxophosphine (MDPO) ligand effectively modulated the electronic properties of the metal centers, which contributed to the construction of a highly dispersed Cu–P/Cl local structure with Cu1+/Cu2+ as a plausible active center. The sintering of active components in the catalyst may be one of the main reasons for the decrease in catalytic performance. Meanwhile, the enhanced adsorption and activation of the catalyst for C2H2 and HCl molecules resulted in improved coking resistance. The most active catalyst (15% Cu8MDPO1/AC) could achieve a stable acetylene conversion of 97% at 180 °C, a gas hourly space velocity (GHSV) (C2H2) of 180 h–1, and a feed volume ratio (VHCl/VC2H2) of 1.15, outperforming the benchmark catalyst. The excellent activity and stability in a 300 h laboratory test at a high GHSV and a 3414 h industrial sideline test at an industrial GHSV render the 15% Cu8MDPO1/AC catalyst as a reference for the construction of other catalysts from an environmental, economic, and application prospect perspective.

Detection of HCl molecules by resonantly enhanced sum-frequency mixing of mid- and near-infrared laser pulses

We perform experimental studies of resonantly enhanced sum-frequency mixing (SFM), driven by tunable, spectrally narrowband mid-infrared and fixed-frequency nanosecond laser pulses, aiming at applications in molecular gas detection. The mid-infrared pulses are tuned in the vicinity of two-photon rovibrational transitions in the electronic ground state to provide strong resonance enhancements of the nonlinear susceptibility, while a probe laser at shorter wavelength uses an off-resonant single-photon coupling to excited electronic states. This SFM approach benefits from the advantageous combination of typically small detunings among the mid-infrared, vibrational transitions and the typically large transition dipole moment for couplings of electronic states. Moreover, compared to resonantly enhanced third harmonic generation (THG), a signal wave at much shorter wavelength permits simple and efficient detection. We demonstrate resonantly enhanced SFM via rovibrational states in gaseous hydrogen chloride molecules and compare its features to THG. The SFM spectra offer a large signal-to-noise ratio of 4 orders of magnitude and a detection limit down to a pressure of 0.1 mbar, corresponding to a particle density of $0.35\ifmmode\times\else\texttimes\fi{}{10}^{15}$ per ${\mathrm{cm}}^{3}$.

Perovskite Nanowire Laser for Hydrogen Chloride Gas Sensing.

Detection of hazardous volatile organic and inorganic species is a crucial task for addressing human safety in the chemical industry. Among these species, there are hydrogen halides (HX, X = Cl, Br, I) vastly exploited in numerous technological processes. Therefore, the development of a cost-effective, highly sensitive detector selective to any HX gas is of particular interest. Herein, we demonstrate the optical detection of hydrogen chloride gas with solution-processed halide perovskite nanowire lasers grown on a nanostructured alumina substrate. An anion exchange reaction between a CsPbBr3 nanowire and vaporized HCl molecules results in the formation of a structure consisting of a bromide core and thin mixed-halide CsPb(Cl,Br)3 shell. The shell has a lower refractive index than the core does. Therefore, the formation and further expansion of the shell reduce the field confinement for experimentally observed laser modes and provokes an increase in their frequency. This phenomenon is confirmed by the coherency of the data derived from XPS spectroscopy, EDX analysis, in situ XRD experiments, HRTEM images, and fluorescent microspectroscopy, as well as numerical modeling for Cl- ion diffusion and the shell-thickness-dependent spectral position of eigenmodes in a core-shell perovskite nanowire. The revealed optical response allows the detection of HCl molecules in the 5-500 ppm range. The observed spectral tunability of the perovskite nanowire lasers can be employed not only for sensing but also for their precise spectral tuning.

Evaluation of newly synthesized phosphoramide derivatives as mild steel anti-corrosions using experimental and theoretical approaches

Three new phosphoramide derivatives with the general formula of (R)2P(O)[C9H21N2] (R= Ph, A), (R= OPh, B) (R= OEt, C) were synthesized and characterized by using spectroscopy methods. The inhibition effectiveness of synthesized compounds was inspected using potentiodynamic polarization (PDP), impedance measurement spectroscopy (EIS) and scanning electron microscopy (SEM). The synthesized compounds demonstrated acceptable protection power for the erosion of mild steel in 1 M HCl at room temperature. The PDP studies illustrated that the new phosphoramide derivatives behaved as mixed-type inhibitors. Density functional theory and molecular dynamics (MD) simulations were employed to support experimental results. The molecular electrostatic potential plot, the highest occupied molecular orbital and the lowest unoccupied molecular orbital profiles, thermochemical parameters, and quantum chemical descriptors such as electronic electronegativity, chemical hardness of the ground state, and electrophilicity index were calculated and discussed from a corrosion inhibition view point. With the aim of identifying the most stable configuration of inhibitor-HCl, the HCl molecule was approached to all probable reactive sites of inhibitors determined by MEP plots. The molecule A with the most inhibition efficiency (87.25%) and negative inhibitor-HCl interaction energy (-2.56 kcal mol−1) was chosen to study its adsorption behavior on the Fe (1 1 0) using MD simulations at T = 298, 308, and 318 K and in the presence of n = 1-4 inhibitor molecules. The corrosion behavior was investigated with the help of binding energies, radial distribution function analysis, equilibrated configurations, and mean square displacement (MSD) analysis. The theoretical results were in good accordance with the experimental results.

Relativistic solutions of the morse potential via the formula method

The Dirac equation is solved using the Formula method. A non-relativistic mapping gives energy eigenvalues, in this limit, for a Hamiltonian including the Morse potential. The energies of the H2, LiH, HCl, CO, ScH, ScN, ScF and I2 molecules for both low and high-lying states are computed. Our results are found to be consistent with the literature. Also, new high-lying states for the Morse potential are also reported in the present study. The results of this study indicate that for the energy Eigen values of the H2 molecule, the deviation from the literature becomes more pronounced for the states (n, l) = (5, 20) and (6, 20).

Triphenylamine derivatives functionalized di-ureasil hybrids for information encipherment

Realizing information protection in low cost and large-scale fabrication still casts tough challenges in various aspects primarily involving material synthesis and engineering. Herein, to circumvent these challenges, the method of reversible protonation reactions of triphenylamine (TPA) derivatives grafted with pyridyl groups is intentionally introduced into the di-ureasil hybrids to functionalize the materials with targeted features. The results reveal that the reversible protonation reactions are still observed after homogenously distributing the TPA derivatives into the di-ureasil hybrids because of the organic-inorganic skeleton structure supplying the channels for the penetrations of NH3·H2O and HCl molecules, leading to an obvious emission color switch between red and cyan-green. Moreover, by replacing the pyridyl group with the pyridinium group in a similar molecule structure, the TPA derivatives are able to achieve an eye-cheated optical performance with very closing UV-Vis and emission spectra but lose the stimuli responsive optical performance. Capitalizing on the special features, the strategies designed for information encipherment applications based on the TPA derivatives functionalized di-ureasil hybrids were estimated through direct coating or preparing the inks for the fountain pens to write. This work successfully endows values of the as-synthesized TPA derivatives for the particular application. To compare with the most analogous powder materials applied for information protection applications, the portable security inks show a bright future for commercial applications offering simple operation, easy visual detection, and large-scale fabrications. In addition, the di-ureasil hybrids doped with TPA derivatives also present good performance as warming white-light-emitting films, showing potential for light electronics’ displays.

ВЗАИМОДЕЙСТВИЕ КАНАЛА OMPF ПОРИНА YERSINIA PSEUDOTUBERCULOSIS С НОРФЛОКСАЦИНОМ

This work is devoted to the study of the interaction of Yersinia pseudotuberculosis OmpF porin with norfloxacin hydrochoride (Nf•HCL), a derivative of a fluoroquinolone antibiotic. Using the bilayer lipid membrane (BLM) method, it was found that water-soluble Nf•HCL molecules dissociate into ions and, binding for a short time to sites inside the channel, block the ion current through the OmpF porin pore. The study of the kinetic characteristics of this process, together with the use of the molecular docking method, made it possible to construct a model that explains the pattern of this interaction. It is proposed that inside the porin channel, on opposite sides of the constriction zone, there are two binding sites with the Nf•H+ ion, stabilized mainly by electrostatic interactions. At the same time, binding to the site located inside the channel near the vestibule formed by the outer loops of the porin leads to blocking of the current, due to the creation of spatial difficulties for the movement of K+ and Cl- ions, while binding to the site located at the exit from the channel does not prevent the passage of current.

Optical parametric oscillator and amplifier providing tunable, narrowband nanosecond laser pulses in the mid-infrared with mJ pulse energy

We report on an all-solid-state light source for nanosecond (ns) laser pulses, with broad tunability in the mid-infrared, spectral bandwidth close to the Fourier transform limit, and pulse energy in the mJ regime. To this end, we extend a tunable, continuous wave (cw) singly resonant optical parametric oscillator by an optical parametric pre-amplifier with a periodically poled lithium niobate crystal and a power amplifier stage with two bulk lithium niobate crystals. We demonstrate pulse energies beyond 1 mJ in a tuning range between 3.3 and 3.8 upmu mathrm {m} center wavelength, with options for even larger output pulse energy and tuning range. The total conversion efficiency in the power amplifier reaches 20%. From measurements of absorption spectroscopy, we determine a very narrow linewidth of 108 MHz (full width at half maximum, FWHM), which is only a factor of 1.4 above the Fourier limit. We demonstrate the applicability and versatility of the laser system for nonlinear spectroscopy by resonantly enhanced third harmonic generation and sum frequency mixing in a gas sample of HCl molecules.

On the hydrolysis of iron ions: DFT-based molecular dynamics perspective

Fe[(H2O)6]3+ and Fe[(H2O)6]2+ are the two stable forms of iron aqua complexes with six water molecules surrounding a central metal. In aqueous media, these complexes undergo hydrolysis reactions. Previous DFT studies of this reaction have focused predominantly on single point calculations and geometry optimization. Nevertheless, little attention has been paid to the dynamical behavior of molecules during this reaction. This study provides a comprehensive understanding of the dynamic reaction of both iron aqua complexes. To investigate the behavior of complexes in this regard, DFT-based molecular dynamics simulations were conducted. Prior to any calculation, the multiplicity corresponding to the stable form and the frontier orbital (LUMO) of each complex were determined. The complex is simulated dynamically in the presence of two distinct molecules: water and a negative ion. Two negative ions with distinct nucleophilicity were considered: Cl- and OH-. Each complex exhibited no reaction with the water molecule. Conversely, both complexes interacted with both negative ions and subsequently, two molecules of HCl and a reduced complex are produced during this reaction. In an aqueous medium, the HCl molecule dissociated to produce hydronium and chloride ions. Additionally, simulations of the reactions between the produced complex and negative ions were performed. Each negative ion hydrolyzed each complex to a certain extent. This investigation has revealed that the negative ion (except OH-) is a spectator ion in the series of hydrolysis reactions. In addition, the presence of more nucleophilic negative ions has led to the inclusion of additional steps to the hydrolysis reaction.

Positronium collisions with polar molecules

We calculate elastic and positronium (Ps) break-up cross sections for collisions of Ps with the polar molecules CO, HCl, and LiF in the fixed-nuclei approximation. We incorporate electron exchange and correlation for these processes by using the free-electron-gas model developed earlier for Ps scattering by rare-gas atoms, ${\mathrm{N}}_{2}$, ${\mathrm{O}}_{2}$, and ${\mathrm{CO}}_{2}$ molecules. The present target molecules provide a range of dipole moments from the weakly polar CO to the strongly polar LiF. We find that Ps scattering is similar to electron scattering when the cross sections are plotted as a function of projectile velocity for the targets with smaller dipole moments (CO, HCl). However, we do not see such a similarity for LiF which has a large dipole moment. Below the Ps break-up threshold we observe resonance structures similar to those obtained earlier for the other molecular targets that we have studied.

A comparative computational study of binary complexes of the structural isomers, propargylimine and acrylonitrile, with small molecules in the interstellar medium (ism)

A comparative density functional theory (DFT) study of model binary complexes of the structural isomers, Z-propargylimine (Z-PGIM) and acrylonitrile, with the diatomic molecules HF, HCl, ArH+ and CN─ was undertaken. All interacting species are found in the interstellar medium (ISM), with Z-PGIM being discovered as recently as 2020. Twenty stable dyads were obtained and characterized. Natural bond orbital (NBO) analyses were used to assess the charge redistribution in these complexes and is consistent with the structural and spectroscopic changes identified in this work. Hydrogen bonding is the dominant non-covalent interaction and the frequency shifts were found to be a sensitive indicator for each dyad, especially for the Lewis acids HF and HCl, and would therefore be useful for the spectroscopic identification of these complexes.

Internal Electric Field-Induced Formation of Exotic Linear Acetonitrile Chains.

The application of external electric and magnetic fields is a powerful tool for aligning molecules in a controlled way, if the thermal fluctuations are small. Here we demonstrate that the same holds for internal electric fields in a molecular cluster. The electric field of a single molecular dipole, HCl, is used to manipulate the aggregation mechanism of subsequently added acetonitrile molecules. As a result, we could form exotic linear acetonitrile (CH3CN) chains at 0.37 K, as confirmed by infrared spectroscopy in superfluid helium nanodroplets. These linear chains are not observed in the absence of HCl and can be observed only when the internal electric field created by an HCl molecule is present. The accompanying simulations provide mechanistic insights into steric control, explain the selectivity of the process, and show that non-additive electronic polarization effects systematically enhance the dipole moment of these linear chains. Thus, adding more CH3CN monomers even supports further quasi-linear chain growth.

Heteroatom-containing phosphoramides as carbon steel corrosion inhibitors: Density functional theory and molecular dynamics simulations

In an attempt to introduce a new class of carbon steel corrosion inhibitors, the anti-corrosion properties of two heteroatom-containing phosphoramides; N-(5-methylisoxazol-3-yl)-P,P-diphenylphosphinic amide (MAPP) and diphenyl (5-methylisoxazol-3-yl)phosphoramidate (PMAP) were theoretically investigated. Density functional theory (DFT) calculations were performed using B3LYP functional and 6–31+G(d,p) basis set to evaluate the inhibition efficacy of MAPP and PMAP in the presence of HCl molecule. Based on the frontier molecular orbitals energy gap (Eg), dipole moment, global hardness, electrophilicity, and nucleophilicity values, we concluded that PMAP acts as a strong anti-corrosion. With the aim of identifying the most stable configuration of inhibitor-HCl, the HCl molecule was approached to all probable reactive sites of inhibitors determined by molecular electrostatic potential plots. It was revealed that molecule PMAP forms a stronger hydrogen bond with the HCl molecule and has a higher ΔH (-4.33 kcal.mol−1) than MAPP (ΔH = -3.50 kcal.mol−1). Adsorption behavior of MAPP and PMAP on a Fe (1 1 0) superlattice was studied using molecular dynamics (MD) simulations at T = 298, 308, and 318 K and in the presence of n = 1–4 molecules of MAPP and PMAP. Radial pair distribution function analysis revealed that molecules MAPP and PMAP have the ability to form a chemical bond with metal, and thus protect it from corrosion. The best anti-corrosion performance occurs at T = 298 K and higher concentrations of inhibitors. The adsorption energy of the PMAP molecule on the steel surface (-258.8 kcal.mol−1 at 298 K and for n = 4) is more negative than that of MAPP (-239.5 kcal.mol−1) at the same conditions, indicating that PMAP can be used as an effective corrosion inhibitor for carbon steel in acidic media.

Atomistic kinetic Monte Carlo simulation on atomic layer deposition of TiN thin film

The atomic layer deposition (ALD) process of TiN thin films is widely used in microelectronics, but the detailed growth mechanism is still elusive at the atomistic level. In the present computational study, we carry out kinetic Monte Carlo (kMC) simulations on the ALD process using TiCl4 and NH3 precursors. Based on the on-lattice model, we sort out key reactions relevant for the ALD process such as adsorption/desorption of precursors, generation of surface Cl atoms, and evolution of free HCl and Cl2 molecules. The reaction energies considering local environments are calculated at the level of density functional theory (DFT) while the activation barriers are linearly fitted to sampled cases among distinct reaction families. The resulting kMC model produces the temperature-dependent growth rates and the amounts of Cl residues in reasonable agreement with experiments. The detailed growth pathway is discussed based on the simulation results, which underscores the critical role of surface Cl atoms in the ALD process by generating HCl gas molecules. By revealing the atomistic mechanisms in the TiN-ALD process, the present work would help optimize material properties of TiN thin films.

Solutions of the Schrödinger equation with Hulthén-screened Kratzer potential: Application to Diatomic Molecules

In this study, the Schrödinger equation with the Hulthén plus screened Kratzer potentials (HSKP) are solved via the Nikiforov-Uvarov (NU) and the series expansion methods. We obtained the energy equation and the wave function in closed form with Greene-Aldrich approximation via the NU method. The series expansion method was also used to obtain the energy equation of HSKP. Three distinct cases were obtained from the combined potentials. The energy eigenvalues of HSKP for HCl, LiH, H2, and NO diatomic molecules were computed for various quantum states. To test the accuracy of our results, we computed the bound states energy of HCl and LiH, for a special case of Kratzer and screened Kratzer potentials, which are in excellent agreement with the report of other researchers.

55‐3: Development of Low‐Temperature Metal Dry‐Etching Equipment via ECR Plasma Source

This paper presents the dry etching performance and expectation of highly conductive thin metal films that are hardly etched at low temperature with conventional plasma dry etching equipment. Dry etching is performed using a combination of H2 and HCl gases in a reactive ion etching system with low temperature susceptor and electron cyclotron resonance (ECR) plasma source. We could achieve high electron temperature enough to dissociate and ionize H and Cl radicals from H2 and HCl molecules.

Reduction of HgCl2 to Hg0 in flue gas at high temperature. Part Ⅰ: Influences of oxidative species

The reduction of gaseous oxidized mercury Hg2+(g) to elemental mercury Hg0(g) is a key technology to obtain the total flue gas mercury in the mercury continuous emission monitoring system (Hg-CEMS). Investigation of the reduction of HgCl2(g) to Hg0(g) in the high-temperature decomposition (HTD) was conducted with/without oxidative components in a fixed bed reactor. The chemical reaction path was discussed in-depth by thermodynamic calculation and theoretical analysis. The results show that the higher the temperature, the higher the efficiency of HgCl2(g) reduction. The chlorine species produced in the HTD process inhibit the conversion rate because of re-oxidation on Hg0(g). For eliminating the negative effect of Cl radicals and promoting the reactive sites, a quartz filler with appropriate size demonstrates a good performance for enhancing the decomposition of HgCl2(g). However, the presence of O2 and HCl leads to the complete failure of HgCl2(g) HTD because O2 greatly promotes the combination of Hg0(g) with chlorine. Compared with HCl molecules, Cl atoms are more active in thermodynamic favor in speeding up re-oxidation of Hg0(g). Active Cl atoms are the most crucial factor hindering HTD reaction due to their high reaction initiative and low activation energy.

Differential Ionization Cross Sections of HCl Molecule

In this article, the differential ionization cross-sections of the HCl molecule in the gas phase is investigated. The single differential ionization cross-section (SDCS) as a function of loss of incident electron energy and Double Differential Cross Section (DDCS) as a function of energy loss of incident electron and incident angle, is calculated. To reach exact values of differential ionization cross sections for HCl molecule, a modified semi-empirical approach of Jain and Khare is used. Partial and total absolute ionization cross-section of HCl is available but there is no data for differential ionization crosssections. So, first time, the results for single and double differential ionization cross-sections for HCl molecule is investigated.