Hydrogen Chloride Molecule Research Articles

Preserving the symmetry of cis-1,2-difluoroethylene in the gas-phase heterodimer with hydrogen chloride: A microwave rotational study revealing a novel structure.

The microwave spectra of three isotopologues of the gas-phase heterodimer formed between cis-1,2-difluoroethylene and hydrogen chloride are obtained in the 5-21GHz region using Fourier transform microwave spectroscopy. The molecular structure, determined from the analysis of the spectra and supported by quantum chemistry calculations, has the hydrogen atom of the hydrogen chloride molecule interacting with both fluorine atoms of the fluoroethylene and no interaction between the chlorine atom and the olefin. Although the equilibrium structure has two inequivalent H⋯F interactions, zero-point motion averages over the two equivalent choices for these interactions, rendering the pairs of like atoms (C, H, and F) of the fluoroethylene equivalent, retaining the C2v symmetry of the olefin. This results in only one unique singly substituted 13C isotopologue and in the observed effects on transition intensities due to nuclear spin statistics. The heterodimer structure allows for a strong, linear hydrogen bond between the HCl donor and the fluoroethylene acceptor that is more important here than in the analogous acetylene containing complex, where the interaction between the π electrons of acetylene and an electrophilic hydrogen atom on the olefin compensates for the loss of linearity required for binding to a geminal F/H pair.

Effect of annealing on corrosion resistance and mechanical properties of Cr–Fe–Ni–Co–Mo–Si–B amorphous coating

Cr–Fe–Ni–Co–Mo–Si–B amorphous coating was successfully prepared on 316 L steel using atmospheric plasma spraying (APS). The effects of different annealing temperatures on the crystallization process of amorphous coatings, thus on the corrosion resistance and mechanical properties of coatings were studied. The results indicated that heat treatment can increase the hardness of the amorphous coating by 12.5% and reduce the wear rate by 30%. In addition, compared to heat-treated coatings, the amorphous coating had the highest corrosion voltage (−0.506V) and lower corrosion current (5.609 × 10−6 A). The passivation film on the amorphous coating provided the best protection due to the relatively high content of Cr2O3. The molecular dynamics (MD) calculation results also indicated that the adsorption energy of hydrogen chloride molecules on Cr–Fe–Ni–Co–Mo–Si–B amorphous coating (−90.94 kcal/mol) was greater than that of 316 L (−293.03 kcal/mol).

Stereoselectivity of Acetylene Hydrochlorination over Supported PdCl<sub>2</sub>/С Catalysts

The products of catalytic hydrochlorination of acetylene-D2 over palladium chloride complexes supported on activated carbon are a mixture of vinyl chloride stereoisomers resulting from syn- and anti-addition of the hydrogen chloride molecule to the triple bond. The reaction is accompanied by isomerization of primary trans-vinyl chloride into its cis-stereoisomer, but the characteristic isomerization times exceed significantly the duration of acetylene hydrochlorination. This fact allowed us to estimate the portion of products formed exclusively during the catalytic reaction, the difference in the effective activation energies of the syn- and anti-addition routes (~21 kJ/mol), and to demonstrate a monotonic increase in the part of the syn-addition product with increasing mass loading ω of the active metal, reaching saturation at ω 2 wt %.

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 ${\mathrm{cm}}^{3}$.

Photoinduced 6π‐electrocyclization of 2,5‐dichlorothiophene containing benzofuranylacrylonitriles as efficient method for the generation of hydrogen chloride

AbstractThe photochemical 6π‐electrocyclization of 1,3,5‐hexatriene system containing benzofuran and 2,5‐dichlorothiophene fragments was investigated. It was shown that considered photoreaction regiospecifically leads to the formation of substituted benzo[b]thieno[2,3‐g]benzofurans. Along with the formation of polyheterocyclic products the studied process is accompanied by the elimination of hydrogen chloride molecule. Based on the suggested transformation an efficient method for the photogeneration of strong acid was implemented. As a result, the starting thienyl substituted benzofurans can be used as photoacid generators (PAGs). The structure of one of the final products was established by X‐ray diffraction.

Construction of multistage porous carbon materials for the hydrochlorination of acetylene: Impact of nitrogen incorporation

The benchmark carbon-based catalyst, activated carbon (AC), has a low catalytic activity due to its uniform surface charge distribution and stable structure. To overcome these problems, melamine-phenol-formaldehyde (MPF) resin, which is rich in pyridinic N and pyrrolic N, multi-porous C-N materials rich with defect sites were synthesized in situ by heat treatment using silica sol as the template and phenol, melamine, and formaldehyde as the carbon and nitrogen sources. The experimental results and characterization techniques revealed that carbon materials with abundant hierarchical pores and local C-N active sites were constructed by incorporating heteroatom-containing groups. Hydrogen chloride and acetylene molecules were activated due to the high electronegativity of defective sites, and the synergistic interactions between pyridinic N and π-containing functional groups (C=C, triazine ring, etc.). The structure-performance relationship was also clarified using DFT calculations. In addition, the strong interactions between heteroatomic sites and metal species also made MPF-800 an admirable metal catalyst support. Overall, the disadvantages of acetylene hydrochlorination catalyzed by benchmark AC were resolved.

Morse potential specific heat with applications: an integral equations theory based

The specific heat in its molar form or mass form is a significant thermal property in the study of the thermal capacity of the described system. There are two basic methods for the determination of the molar specific heat capacity, one of them is the experimental procedure and the other is the theoretical procedure. The present study deals with finding a formula of the molar specific heat capacity using the theory of the integral equations for Morse interaction which is a very important potential for the study of the general oscillations in the quantum mechanics. We use the approximation (Mean-Spherical) for finding the total energy of the compositions described by Morse interaction. We find two formulas of the heat capacity, one at a constant pressure and the other at a constant volume. We conclude that the Morse molar specific heat is temperature dependent via the inverse square low with respect to temperature. Besides, we find that the Morse molar specific heat is proportional to the square of the Morse interaction well depth. Also, we find that the Morse molar specific heat depends on the particles’ diameter, the bond distance of Morse interaction, the width parameter of Morse interaction, and the volumetric density of the system. We apply the formula of the specific heat for finding the specific heat of the vibrational part for two dimer which are the lithium and caesium dimers and for the hydrogen fluoride, hydrogen chloride, nitrogen, and hydrogen molecules.

Bulk modulus for Morse potential interaction with the distribution function based

The bulk modulus is a significant coefficient for the study of the compressible behaviour of the materials in the bulk case. The bulk moduli can be determined via the experimental method by measuring of the elastic parameters, via the semi-empirical procedures from the equation of state, or from theoretical images as in the theory of the integral equations. In this work we find a relationship of the bulk modulus for the Morse interaction potential employing the Fourier transformation and the mean-spherical approximation for the Morse interaction. We find that the bulk modulus of the Morse potential is composed of two terms, one from the kinetic part, and the other from the internal interaction of the particles composing the described-system. We find that the bulk modulus of the Morse interaction depends on the absolute temperature of the described composition and the compact factor. Besides, we find that the Bulk modulus formula which we derived of Morse potential, depends on the diameter of the particles in the system, and depends on the Morse interaction parameters. The formula which we derive is, in general, applied for the systems described by the Morse interaction in the vibrational case such as the hydrogen chloride and hydrogen fluoride molecules.

Metal-free transfer hydrochlorination of internal C-C triple bonds with a bicyclo[3.1.0]hexane-based surrogate releasing two molecules of hydrogen chloride.

The development and application of a transfer hydrochlorination reagent based on a trichlorinated bicyclo[3.1.0]hexane core that transfers two molecules of HCl per molecule of surrogate to a π-basic substrate under B(C6F5)3 catalysis is reported. Lewis acid-assisted chloride abstraction followed by thermal electrocyclic cyclopropyl-to-allyl cation ring opening releases ring strain as a previously unexploited driving force.

The bond length of the improved Rosen Morse potential, applying for: Cesium, hydrogen, hydrogen fluoride, hydrogen chloride, lithium, and nitrogen molecules

One of the generalized vibrational potentials is the improved Rosen Morse potential (IRMP), which is used in vibrational interactions studies, especially, for the study of the vibrations of the diatomic systems or dimers. The IRMP interaction has three independent fitting parameters which are the bond equilibrium length of the IRMP, the energy well depth of the IRMP, and the range of the well of potential parameter. In this study, the principles of the integral equation theory of the simple fluids are employed with the boundary conditions for deriving a simple formula between the bond equilibrium length of the IRMP and the other two fitting parameters of the IRMP interaction. We investigate the relation between the bond equilibrium length of the IRMP interaction and the absolute temperature. We find that the bond equilibrium length of the IRMP interaction depends on the absolute temperature of the system, and increases slowly with the absolute temperature. Also, we find that the bond equilibrium length of the IRMP interaction depends on the diameter of the particles in the system, and also increases with the diameter of the particles for different temperature values and for different values of the depth of the IRMP well. We find that the bond equilibrium length of the IRMP interaction decreases when the depth of the IRMP well increases for different values of temperature, also we find that this bond length increases when the range of the well of the IRMP parameter increases for different values of temperature and for different values of the depth of the IRMP well. We apply our formula of the bond equilibrium length of the IRMP interaction for six different molecules and dimers, which are the caesium dimer (Cs2), the lithium dimer (Li2), the hydrogen chloride (HCl), the hydrogen fluoride (HF), the nitrogen molecule (N2), and the hydrogen molecule (H2). We find that, in general, the bond equilibrium length of the IRMP interaction for these molecules and dimers is between 0.9 Å and 7Å for a wide range of temperatures, and the largest value is for the caesium dimer and the lowest value is for the hydrogen fluoride molecule. The formula which we derive for the bond equilibrium length of the IRMP interaction can be applied further to a wide range of molecules and dimers.

Impact on Poly(Vinyl chloride) of trimethoprim schiff bases as stabilizers

Poly(vinyl chloride) PVC materials are used in many industrial and household outdoor applications which exposed to sunlight ultraviolet. This exposure motivates photo-degradation of the PVC and hence, reduces its life time and leads to undesirable physical properties. Herein, three new Schiff bases containing a trimethoprim moiety were investigated as photo-stabilizers for poly(vinyl chloride) against photo-decomposition. Merely 0.5% by weight of these Schiff bases was mixed with the polymer to form blend films with thickness of (40 µm). The films were irradiated for a period of time from 0 to 300 h and the irradiation impact on the PVC stabilization was monitored every 50 h. The efficiency of these additives as photo-stabilizers was investigated as a function of different parameters during the course of irradiation, such as weight loss, growing carbonyl and alkene groups as well as the surface morphology of the prepared films. The changes during irradiation were obvious for the blank films in comparison to the films containing the new additives. Therefore, these Schiff bases were found to act as photo-degradation inhibitors through reducing the elimination of hydrogen chloride molecules and as free radical scavengers or peroxide decomposers.

Purification of polyynes via carbides

The synthesis of carbyne has remained an elusive goal for decades. One of the significant reasons is that high-purity and high-concentration hydrogen end-capped polyynes (C2nH2) as the most important model molecule and precursors for carbyne have been not widely prepared. Herein, we develop a facile and universal strategy to obtain high-purity and high-concentration C8-18H2 molecules using solid linear carbon chains with silver atom ending-capped (Ag2C8-18) as reaction precursors. The purified and concentrated C8-18H2 solution and Ag2C8-18 powder are evaluated by a combination of X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, Raman spectroscopy, UV–vis–NIR spectroscopy and transmission electron microscope. These results confirm that the high-purity and high-concentration C2nH2 are obtained through the reaction of metal carbides solid and hydrogen chloride molecule. Our strategy for investigating unprotected linear carbon chains in solid and the successful preparation of high-concentration C2nH2 from solid carbides provide a new avenue for the research of linear carbon chains.

Mass spectrum of heavy quarkonium for screened Kratzer potential (SKP) using series expansion method

In this study, the radial Schrodinger equation is solved with the screened Kratzer potential using the series expansion method. The bound state energy spectra are obtained. To check the correctness of the result obtained from this method, we carry out suitable adjustments to the screened Kratzer potential parameters resulting in potential models, such as the Kratzer and Coulomb potentials are deduced as special cases. The numerical values of the energy spectra of the special cases (Kratzer potential) for hydrogen chloride and lithium hydride diatomic molecules are computed for different quantum numbers; n and l and the results are in consonance with the theoretical works of similar investigation. The expression for the energy spectra is applied to obtain the mass spectra of heavy quarkonium systems (charmonium and bottomonium). The numerical results agree with the experimental values and theoretical studies in previous works. Our results will have possible applications in high energy physics, molecular physics, etc.

Validation of SMILES HCl profiles over a wide range from the stratosphere to the lower thermosphere

Abstract. Hydrogen chloride (HCl) is the most abundant (more than 95 %) among inorganic chlorine compounds Cly in the upper stratosphere. The HCl molecule is observed to obtain long-term quantitative estimations of the total budget of the stratospheric chlorine compounds. In this study, we provided HCl vertical profiles at altitudes of 16–100 km using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) from space. The HCl vertical profile from the upper troposphere to the lower thermosphere is reported for the first time from SMILES observations; the data quality is quantified by comparison with other measurements and via theoretical error analysis. We used the SMILES level-2 research product version 3.0.0. The period of the SMILES HCl observation was from 12 October 2009 to 21 April 2010, and the latitude coverage was 40∘ S–65∘ N. The average HCl vertical profile showed an increase with altitude up to the stratopause (∼ 45 km), approximately constant values between the stratopause and the upper mesosphere (∼ 80 km), and a decrease from the mesopause to the lower thermosphere (∼ 100 km). This behavior was observed in all latitude regions and reproduced by the Whole Atmosphere Community Climate Model in the specified dynamics configuration (SD-WACCM). We compared the SMILES HCl vertical profiles in the stratosphere and lower mesosphere with HCl profiles from Microwave Limb Sounder (MLS) on the Aura satellite, as well as from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) on SCISAT and the TErahertz and submillimeter LImb Sounder (TELIS) (balloon borne). The TELIS observations were performed using the superconductive limb emission technique, as used by SMILES. The globally averaged vertical HCl profiles of SMILES agreed well with those of MLS and ACE-FTS within 0.25 and 0.2 ppbv between 20 and 40 km (within 10 % between 30 and 40 km; there is a larger discrepancy below 30 km), respectively. The SMILES HCl concentration was smaller than those of MLS and ACE-FTS as the altitude increased from 40 km, and the difference was approximately 0.4–0.5 ppbv (12 %–15 %) at 50–60 km. The difference between SMILES and TELIS HCl observations was about 0.3 ppbv in the polar winter region between 20 and 34 km, except near 26 km. SMILES HCl error sources that may cause discrepancies with the other observations are investigated by a theoretical error analysis. We calculated errors caused by the uncertainties of spectroscopic parameters, instrument functions, and atmospheric temperature profiles. The Jacobian for the temperature explains the negative bias of the SMILES HCl concentrations at 50–60 km.

An algorithm for fractional Schrödinger equation in case of Morse potential

Based on methods of numerical integration and Riemann–Liouville definition of the fractional derivatives, we find a numerical algorithm to find solutions of the time independent fractional Schrödinger equation for Morse potential or the quantum oscillator potential in one dimension, and the iteration formula is applied for multiple values of the fractional parameter of the space dependent fractional Schrödinger equation and multiple values of energy. We define and use the dimensionless form of the space dependent fractional Schrödinger equation of Morse potential. We employ the iteration formula of the time independent fractional Schrödinger equation of Morse potential to find the wave functions in the case of hydrogen chloride and hydrogen fluoride molecules for a certain value of the fractional parameter of the space dependent fractional Schrödinger equation and for many values of the dimensionless energy of each molecule.

Experimental and theoretical study on the behaviour of a pickling solution: The role of ferrous ions

Abstract The existence of ferrous ions plays an important role in the performance of pickling liquor as well as the recovery of hydrochloric acid from waste pickling liquor. The promotion mechanism and the interaction between ferrous ions and hydrogen chloride molecules have remained largely unsolved. In this research, the fundamental aspects of a simulated hydrochloric acid pickling solution with different concentrations of ferrous ions were experimentally and theoretically studied. The experimental results showed that the existence of ferrous ions in the pickling liquor effectively inhibited the volatilisation of hydrogen chloride from solution and that the inhibition of volatilisation enhanced with an increase in concentration of ferrous ions. To understand the interaction between ferrous ions and hydrogen chloride molecules, the structure and thermodynamic properties of possible hydration structures were obtained by using molecular simulation. The results showed that a new type of cluster, hydrogen chloride-ferrous ion-water, was formed in the presence of ferrous ions, which made the hydrogen chloride molecules in the pickling liquor more stable compared to the same condition without ferrous ions. The existence of ferrous ions in pickling liquor benefits the pickling process from an economic and environmental aspect.

Экспериментальное и теоретическое изучение фрагментации дихлор-3-арил-2,1-бензизоксазолов

2,1-Benzisoxazoles or anthranyls have different types of biological activity, are used to obtain monomers for polymeric materials, dyes and other heterocyclic compounds. In addition, 2,1-benzisoxazoles attract the attention of researchers due to the presence of a weak N-O bond, which is a potential place for the opening of the cycle in the reactions of reduction, oxidation, and various transformations. Therefore, it is very important to study their structure, methods of identification and reactivity in the processes taking place with their participation. One of the most effective modern research methods in chemistry is chromatography-mass spectrometry and quantum-chemical modeling. And since the fragmentation of molecules during their electron impact ionization depends on the nature of the compounds and characterizes their reactivity in various types of chemical reactions, the aim of this work was to experimentally and theoretically study the fragmentation of dichloro-3-phenyl-2,1-benzisoxazoles. For this, the corresponding dichloro-3-aryl-2,1-benzisoxazoles were synthesized by condensation of nitroarenes with arylacetonitriles in the presence of an excess of sodium hydroxide. The chromatography-mass spectrometry method was used to study the directions of fragmentation of their molecular ions. It was found that for all the compounds studied, similar fragment fragments are observed in the mass spectra, which indicates similar patterns of their fragmentation. Based on the data of quantum chemical modeling using the PC GAMESS/FireFly 8.2 software package using the density func-tional theory method, it was suggested that even before the decay of the molecular ions of dichloro-3-aryl-2,1-benzisoxazoles, they rapidly transform into the corresponding cation radicals of dichloroacridinones with the same atomic composition. Further decomposition of dichloroacridinone ions is accompanied by the release of a chlorine atom, carbon monoxide and skeletal rearrangement with the formation of the corresponding chlorocarbazole ions. Chlorocarbazole ions then eject a hydrogen chloride molecule to form a cation with m/z 164 and atomic composition C12H6N.

Hydrogen chloride adsorption on large defective PAHs modeling soot surfaces and influence on water trapping: A DFT and AIMD study

DFT calculations both at 0 K in energy optimization procedure and at finite temperature in ab initio molecular dynamics (AIMD) calculations are used to characterize the adsorption of the hydrogen chloride molecule on a carbonaceous cluster in which a carbon vacancy has been created by removing one carbon atom. This aims at modeling the defective surface of the small graphitic basic structural units that constitute soot nanoparticles, as experimentally evidenced. The results show that HCl can be easily dissociated at the vacancy site of the surface, resulting in the formation of a chlorinated site at the carbonaceous surface, which could have different structures depending on the thermodynamics of the reactions. Then, the resulting chlorinated carbonaceous surfaces are used as model substrates to characterize the first stages of the adsorption of water molecules on chlorinated soot. It is thus shown that adsorbed chlorine atoms may act as an efficient nucleation center for water trapping at the surface of soot. These results represent a new step towards a better understanding of the soot behavior in industrial or domestic fire situations, as well as in marine atmospheric environment where oxidant and chlorinated species are ubiquitous.

Кинетика и механизм реакций ацильного переноса. Часть 15. Квантово-химическое моделирование механизмов реакций сульфонилирования N-этиланилина

The RHF/6-31G(d) quantum chemical simulation of the mechanism of the interaction of the secondary fatty aromatic amine N-ethylaniline with benzenesulfonyl chloride under conditions of non-specific water solvation, using the continuum model of the solvent, as well as of sulfonylation reactions of N-ethylaniline solvation complexes containing one water molecule, modeled specific solvation of N-ethylaniline with water, and one molecule of water and one of dioxane, which simulate the solvation of the amine with aqueous dioxane. Three-dimensional potential energy surface of these processes is calculated. It is shown that in the case of a reaction proceeding under conditions of non-specific solvation of reagents, the route with axial attack of the N-ethylaniline molecule to the sulfonyl reaction center is realized, in the two other cases the reactions proceed along a single route, starting as an axial attack of the nucleophile, which goes further with decreasing of the attack angle as reagent molecules approach each other. It was established that all the simulated reactions proceed in accordance with bimolecular coordinated mechanism of nucleophilic substitution SN2, which implies the formation of a single transition state in the reaction path. It was found that geometrical configuration of the reaction center in the transition state of N-ethylaniline reaction with benzenesulfonyl chloride under non-specific solvation by water is close to trigonal-bipyramidal, which is determined by the axial direction of the nucleophilic attack, in the two other cases it is medium between the trigonal-bipyramidal and tetragonal-pyramidal, which is associated with the change in the angle of N-ethylaniline attack as the reactant molecules approach each other. In a reaction involving N-ethylaniline monohydrate, a water molecule forms a 6-membered cyclic structure with reagent molecules in the transition state, in which the transfer of a proton from N-ethylaniline amino group to a hydrogen chloride molecule occurs via a relay mechanism involving the water molecule. The activation energy values of the studied processes were calculated; it is shown that both specific and universal solvation significantly lower the energy barrier of the reaction compared to the reaction occurring in gas phase, which is consistent with the data obtained earlier for related processes.

Dissociative frustrated multiple ionization of hydrogen chloride in intense femtosecond laser fields

The dissociative frustrated multiple ionization of hydrogen chloride (HCl) molecules in intense femtosecond laser fields is investigated by employing the coincidence measurement technique in cold target recoil ion momentum spectroscopy. Various dissociative frustrated multiple ionization channels caused by populating one or two electrons to highly excited Rydberg states can be clearly distinguished for HCl in linearly polarized intense laser fields. The excited charged fragmentations, depending on their occupied principle quantum numbers, can be either directly identified forming a ``knee'' structure in the kinetic energy release spectrum, or singly ionized by the weak electric field in the spectrometer, or by blackbody radiation after the conclusion of the laser pulse. The inherent feature of the potential energy curves of HCl plays an important role in the strong-field dissociative frustrated multiple ionization process.